TY - JOUR T1 - Therapeutic relevance of the protein phosphatase 2A in cancer JF - Oncotarget.com Y1 - 2016 A1 - Cunningham, Chelsea E. A1 - Li, Shuangshuang A1 - Vizeacoumar, Frederick S. A1 - Bhanumathy, Kalpana Kalyanasundaram A1 - Lee, Joo Sang A1 - Parameswaran, Sreejit A1 - Furber, Levi A1 - Abuhussein, Omar A1 - Paul, James M. A1 - McDonald, Megan A1 - Templeton, Shaina D. A1 - Shukla, Hersh A1 - El Zawily, Amr M. A1 - Boyd, Frederick A1 - Alli, Nezeka A1 - Mousseau, Darrell D. A1 - Geyer, Ron A1 - Bonham, Keith A1 - Anderson, Deborah H. A1 - Yan, Jiong A1 - Yu-Lee, Li-Yuan A1 - Weaver, Beth A. A1 - Uppalapati, Maruti A1 - Ruppin, Eytan A1 - Sablina, Anna A1 - Freywald, Andrew A1 - Vizeacoumar, Franco J. UR - https://www.oncotarget.com/article/11399 J1 - Oncotarget M3 - 10.18632/oncotarget.11399 ER - TY - JOUR T1 - Transcriptome Remodeling in Trypanosoma cruzi and Human Cells during Intracellular Infection. JF - PLoS Pathog Y1 - 2016 A1 - Li, Yuan A1 - Shah-Simpson, Sheena A1 - Okrah, Kwame A1 - Belew, A Trey A1 - Choi, Jungmin A1 - Caradonna, Kacey L A1 - Padmanabhan, Prasad A1 - Ndegwa, David M A1 - Temanni, M Ramzi A1 - Corrada Bravo, Hector A1 - El-Sayed, Najib M A1 - Burleigh, Barbara A AB -

Intracellular colonization and persistent infection by the kinetoplastid protozoan parasite, Trypanosoma cruzi, underlie the pathogenesis of human Chagas disease. To obtain global insights into the T. cruzi infective process, transcriptome dynamics were simultaneously captured in the parasite and host cells in an infection time course of human fibroblasts. Extensive remodeling of the T. cruzi transcriptome was observed during the early establishment of intracellular infection, coincident with a major developmental transition in the parasite. Contrasting this early response, few additional changes in steady state mRNA levels were detected once mature T. cruzi amastigotes were formed. Our findings suggest that transcriptome remodeling is required to establish a modified template to guide developmental transitions in the parasite, whereas homeostatic functions are regulated independently of transcriptomic changes, similar to that reported in related trypanosomatids. Despite complex mechanisms for regulation of phenotypic expression in T. cruzi, transcriptomic signatures derived from distinct developmental stages mirror known or projected characteristics of T. cruzi biology. Focusing on energy metabolism, we were able to validate predictions forecast in the mRNA expression profiles. We demonstrate measurable differences in the bioenergetic properties of the different mammalian-infective stages of T. cruzi and present additional findings that underscore the importance of mitochondrial electron transport in T. cruzi amastigote growth and survival. Consequences of T. cruzi colonization for the host include dynamic expression of immune response genes and cell cycle regulators with upregulation of host cholesterol and lipid synthesis pathways, which may serve to fuel intracellular T. cruzi growth. Thus, in addition to the biological inferences gained from gene ontology and functional enrichment analysis of differentially expressed genes in parasite and host, our comprehensive, high resolution transcriptomic dataset provides a substantially more detailed interpretation of T. cruzi infection biology and offers a basis for future drug and vaccine discovery efforts.

VL - 12 CP - 4 M3 - 10.1371/journal.ppat.1005511 ER - TY - JOUR T1 - The Theory and Practice of Genome Sequence Assembly JF - Annu Rev Genomics Hum GenetAnnu Rev Genomics Hum Genet Y1 - 2015 A1 - Simpson, J. T. A1 - Pop, M. KW - algorithm KW - Bioinformatics KW - genome sequencing KW - sequence assembly KW - shotgun sequencing AB - The current genomic revolution was made possible by joint advances in genome sequencing technologies and computational approaches for analyzing sequence data. The close interaction between biologists and computational scientists is perhaps most apparent in the development of approaches for sequencing entire genomes, a feat that would not be possible without sophisticated computational tools called genome assemblers (short for genome sequence assemblers). Here, we survey the key developments in algorithms for assembling genome sequences since the development of the first DNA sequencing methods more than 35 years ago. VL - 16 SN - 1545-293X (Electronic)
1527-8204 (Linking) N1 - Simpson, Jared T
Pop, Mihai
eng
2015/05/06 06:00
Annu Rev Genomics Hum Genet. 2015 Aug 24;16:153-72. doi: 10.1146/annurev-genom-090314-050032. Epub 2015 Apr 22. ER - TY - Generic T1 - Transcriptomic profiling of gene expression and RNA processing during Leishmania major differentiation. Y1 - 2015 A1 - Dillon, Laura A L A1 - Okrah, Kwame A1 - Hughitt, V Keith A1 - Suresh, Rahul A1 - Li, Yuan A1 - Fernandes, Maria Cecilia A1 - Belew, A Trey A1 - Corrada Bravo, Hector A1 - Mosser, David M A1 - El-Sayed, Najib M AB -

Protozoan parasites of the genus Leishmania are the etiological agents of leishmaniasis, a group of diseases with a worldwide incidence of 0.9-1.6 million cases per year. We used RNA-seq to conduct a high-resolution transcriptomic analysis of the global changes in gene expression and RNA processing events that occur as L. major transforms from non-infective procyclic promastigotes to infective metacyclic promastigotes. Careful statistical analysis across multiple biological replicates and the removal of batch effects provided a high quality framework for comprehensively analyzing differential gene expression and transcriptome remodeling in this pathogen as it acquires its infectivity. We also identified precise 5' and 3' UTR boundaries for a majority of Leishmania genes and detected widespread alternative trans-splicing and polyadenylation. An investigation of possible correlations between stage-specific preferential trans-splicing or polyadenylation sites and differentially expressed genes revealed a lack of systematic association, establishing that differences in expression levels cannot be attributed to stage-regulated alternative RNA processing. Our findings build on and improve existing expression datasets and provide a substantially more detailed view of L. major biology that will inform the field and potentially provide a stronger basis for drug discovery and vaccine development efforts.

JA - Nucleic Acids Res VL - 43 CP - 14 M3 - 10.1093/nar/gkv656 ER - TY - JOUR T1 - TIPP:Taxonomic Identification and Phylogenetic Profiling JF - BioinformaticsBioinformatics Y1 - 2014 A1 - Nguyen, Nam-phuong A1 - Mirarab, Siavash A1 - Liu, Bo A1 - Pop, Mihai A1 - Warnow, Tandy AB - Motivation: Abundance profiling (also called “phylogenetic profiling”) is a crucial step in understanding the diversity of a metagenomic sample, and one of the basic techniques used for this is taxonomic identification of the metagenomic reads.Results: We present TIPP (taxon identification and phylogenetic profiling), a new marker-based taxon identification and abundance profiling method. TIPP combines SEPP, a phylogenetic placement method, with statistical techniques to control the classification precision and recall, and results in improved abundance profiles. TIPP is highly accurate even in the presence of high indel errors and novel genomes, and matches or improves on previous approaches, including NBC, mOTU, PhymmBL, MetaPhyler, and MetaPhlAn.Availability: Software and supplementary materials are available at http://www.cs.utexas.edu/users/phylo/software/sepp/tipp-submission/.Contact: warnow@illinois.edu ER - TY - JOUR T1 - Three independent determinants of protein evolutionary rate JF - J Mol EvolJ Mol EvolJ Mol Evol Y1 - 2013 A1 - Choi, S. S. A1 - Sridhar Hannenhalli KW - *Evolution, Molecular KW - *Mutation Rate KW - Animals KW - Genes/physiology KW - Genetic Fitness KW - HUMANS KW - Models, Genetic KW - Protein Biosynthesis/genetics KW - Protein Folding KW - Protein Interaction Domains and Motifs/genetics KW - Proteins/chemistry/*genetics/metabolism AB - One of the most widely accepted ideas related to the evolutionary rates of proteins is that functionally important residues or regions evolve slower than other regions, a reasonable outcome of which should be a slower evolutionary rate of the proteins with a higher density of functionally important sites. Oddly, the role of functional importance, mainly measured by essentiality, in determining evolutionary rate has been challenged in recent studies. Several variables other than protein essentiality, such as expression level, gene compactness, protein-protein interactions, etc., have been suggested to affect protein evolutionary rate. In the present review, we try to refine the concept of functional importance of a gene, and consider three factors-functional importance, expression level, and gene compactness, as independent determinants of evolutionary rate of a protein, based not only on their known correlation with evolutionary rate but also on a reasonable mechanistic model. We suggest a framework based on these mechanistic models to correctly interpret the correlations between evolutionary rates and the various variables as well as the interrelationships among the variables. VL - 76 SN - 1432-1432 (Electronic)
0022-2844 (Linking) N1 - Choi, Sun Shim
Hannenhalli, Sridhar
eng
R01GM085226/GM/NIGMS NIH HHS/
Research Support, N.I.H., Extramural
Research Support, Non-U.S. Gov't
Review
Germany
2013/02/13 06:00
J Mol Evol. 2013 Mar;76(3):98-111. doi: 10.1007/s00239-013-9543-6. Epub 2013 Feb 12. J1 - Journal of molecular evolutionJournal of molecular evolution ER - TY - JOUR T1 - TIGRFAMs and Genome Properties in 2013. JF - Nucleic Acids Res Y1 - 2013 A1 - Haft, Daniel H A1 - Selengut, Jeremy D A1 - Richter, Roland A A1 - Harkins, Derek A1 - Basu, Malay K A1 - Beck, Erin KW - Databases, Protein KW - Genome, Archaeal KW - Genome, Bacterial KW - Genomics KW - Internet KW - Markov chains KW - Molecular Sequence Annotation KW - Proteins KW - sequence alignment AB -

TIGRFAMs, available online at http://www.jcvi.org/tigrfams is a database of protein family definitions. Each entry features a seed alignment of trusted representative sequences, a hidden Markov model (HMM) built from that alignment, cutoff scores that let automated annotation pipelines decide which proteins are members, and annotations for transfer onto member proteins. Most TIGRFAMs models are designated equivalog, meaning they assign a specific name to proteins conserved in function from a common ancestral sequence. Models describing more functionally heterogeneous families are designated subfamily or domain, and assign less specific but more widely applicable annotations. The Genome Properties database, available at http://www.jcvi.org/genome-properties, specifies how computed evidence, including TIGRFAMs HMM results, should be used to judge whether an enzymatic pathway, a protein complex or another type of molecular subsystem is encoded in a genome. TIGRFAMs and Genome Properties content are developed in concert because subsystems reconstruction for large numbers of genomes guides selection of seed alignment sequences and cutoff values during protein family construction. Both databases specialize heavily in bacterial and archaeal subsystems. At present, 4284 models appear in TIGRFAMs, while 628 systems are described by Genome Properties. Content derives both from subsystem discovery work and from biocuration of the scientific literature.

VL - 41 CP - Database issue M3 - 10.1093/nar/gks1234 ER - TY - JOUR T1 - TIGRFAMs and Genome Properties in 2013 JF - Nucleic acids researchNucleic Acids Research Y1 - 2013 A1 - Haft, Daniel H. A1 - J. Selengut A1 - Richter, Roland A. A1 - Harkins, Derek A1 - Basu, Malay K. A1 - Beck, Erin KW - Databases, Protein KW - Genome, Archaeal KW - Genome, Bacterial KW - Genomics KW - Internet KW - Markov chains KW - Molecular Sequence Annotation KW - Proteins KW - sequence alignment AB - TIGRFAMs, available online at http://www.jcvi.org/tigrfams is a database of protein family definitions. Each entry features a seed alignment of trusted representative sequences, a hidden Markov model (HMM) built from that alignment, cutoff scores that let automated annotation pipelines decide which proteins are members, and annotations for transfer onto member proteins. Most TIGRFAMs models are designated equivalog, meaning they assign a specific name to proteins conserved in function from a common ancestral sequence. Models describing more functionally heterogeneous families are designated subfamily or domain, and assign less specific but more widely applicable annotations. The Genome Properties database, available at http://www.jcvi.org/genome-properties, specifies how computed evidence, including TIGRFAMs HMM results, should be used to judge whether an enzymatic pathway, a protein complex or another type of molecular subsystem is encoded in a genome. TIGRFAMs and Genome Properties content are developed in concert because subsystems reconstruction for large numbers of genomes guides selection of seed alignment sequences and cutoff values during protein family construction. Both databases specialize heavily in bacterial and archaeal subsystems. At present, 4284 models appear in TIGRFAMs, while 628 systems are described by Genome Properties. Content derives both from subsystem discovery work and from biocuration of the scientific literature. VL - 41 N1 - http://www.ncbi.nlm.nih.gov/pubmed/23197656?dopt=Abstract ER - TY - CONF T1 - Topological properties of chromosome conformation graphs reflect spatial proximities within chromatin T2 - Proceedings of the International Conference on Bioinformatics, Computational Biology and Biomedical Informatics Y1 - 2013 A1 - Hao Wang A1 - Geet Duggal A1 - Rob Patro A1 - Michelle Girvan A1 - Sridhar Hannenhalli A1 - Carl Kingsford JA - Proceedings of the International Conference on Bioinformatics, Computational Biology and Biomedical Informatics PB - ACM CY - Wshington DC, USA U1 - 2506633 ER - TY - JOUR T1 - Temporal and Spatial Variability in the Distribution of Vibrio vulnificus in the Chesapeake Bay: A Hindcast Study JF - EcoHealthEcoHealth Y1 - 2012 A1 - Banakar, V. A1 - Constantin de Magny, G. A1 - Jacobs, J. A1 - Murtugudde, R. A1 - Huq, A. A1 - J. Wood, R. A1 - Rita R. Colwell AB - Vibrio vulnificus, an estuarine bacterium, is the causative agent of seafood-related gastroenteritis, primary septicemia, and wound infections worldwide. It occurs as part of the normal microflora of coastal marine environments and can be isolated from water, sediment, and oysters. Hindcast prediction was undertaken to determine spatial and temporal variability in the likelihood of occurrence of V. vulnificus in surface waters of the Chesapeake Bay. Hindcast predictions were achieved by forcing a multivariate habitat suitability model with simulated sea surface temperature and salinity in the Bay for the period between 1991 and 2005 and the potential hotspots of occurrence of V. vulnificus in the Chesapeake Bay were identified. The likelihood of occurrence of V. vulnificus during high and low rainfall years was analyzed. From results of the study, it is concluded that hindcast prediction yields an improved understanding of environmental conditions associated with occurrence of V. vulnificus in the Chesapeake Bay. ER - TY - Generic T1 - Transcript expression analysis of putative Trypanosoma brucei GPI-anchored surface proteins during development in the tsetse and mammalian hosts. Y1 - 2012 A1 - Savage, Amy F A1 - Cerqueira, Gustavo C A1 - Regmi, Sandesh A1 - Wu, Yineng A1 - El Sayed, Najib M A1 - Aksoy, Serap KW - Animals KW - Computational Biology KW - Gastrointestinal Tract KW - Gene Expression Profiling KW - GPI-Linked Proteins KW - HUMANS KW - Male KW - Membrane Proteins KW - Protozoan Proteins KW - Real-Time Polymerase Chain Reaction KW - Salivary Glands KW - Trypanosoma brucei brucei KW - Trypanosomiasis, African KW - Tsetse Flies AB -

Human African Trypanosomiasis is a devastating disease caused by the parasite Trypanosoma brucei. Trypanosomes live extracellularly in both the tsetse fly and the mammal. Trypanosome surface proteins can directly interact with the host environment, allowing parasites to effectively establish and maintain infections. Glycosylphosphatidylinositol (GPI) anchoring is a common posttranslational modification associated with eukaryotic surface proteins. In T. brucei, three GPI-anchored major surface proteins have been identified: variant surface glycoproteins (VSGs), procyclic acidic repetitive protein (PARP or procyclins), and brucei alanine rich proteins (BARP). The objective of this study was to select genes encoding predicted GPI-anchored proteins with unknown function(s) from the T. brucei genome and characterize the expression profile of a subset during cyclical development in the tsetse and mammalian hosts. An initial in silico screen of putative T. brucei proteins by Big PI algorithm identified 163 predicted GPI-anchored proteins, 106 of which had no known functions. Application of a second GPI-anchor prediction algorithm (FragAnchor), signal peptide and trans-membrane domain prediction software resulted in the identification of 25 putative hypothetical proteins. Eighty-one gene products with hypothetical functions were analyzed for stage-regulated expression using semi-quantitative RT-PCR. The expression of most of these genes were found to be upregulated in trypanosomes infecting tsetse salivary gland and proventriculus tissues, and 38% were specifically expressed only by parasites infecting salivary gland tissues. Transcripts for all of the genes specifically expressed in salivary glands were also detected in mammalian infective metacyclic trypomastigotes, suggesting a possible role for these putative proteins in invasion and/or establishment processes in the mammalian host. These results represent the first large-scale report of the differential expression of unknown genes encoding predicted T. brucei surface proteins during the complete developmental cycle. This knowledge may form the foundation for the development of future novel transmission blocking strategies against metacyclic parasites.

JA - PLoS Negl Trop Dis VL - 6 CP - 6 M3 - 10.1371/journal.pntd.0001708 ER - TY - JOUR T1 - Temperature regulation of virulence factors in the pathogen Vibrio coralliilyticus JF - The ISME JournalThe ISME journal Y1 - 2011 A1 - Kimes, Nikole E. A1 - Grim, Christopher J. A1 - Johnson, Wesley R. A1 - Hasan, Nur A. A1 - Tall, Ben D. A1 - Kothary, Mahendra H. A1 - Kiss, Hajnalka A1 - Munk, A. Christine A1 - Tapia, Roxanne A1 - Green, Lance A1 - Detter, Chris A1 - Bruce, David C. A1 - Brettin, Thomas S. A1 - Rita R. Colwell A1 - Morris, Pamela J. KW - ecophysiology KW - ecosystems KW - environmental biotechnology KW - geomicrobiology KW - ISME J KW - microbe interactions KW - microbial communities KW - microbial ecology KW - microbial engineering KW - microbial epidemiology KW - microbial genomics KW - microorganisms AB - Sea surface temperatures (SST) are rising because of global climate change. As a result, pathogenic Vibrio species that infect humans and marine organisms during warmer summer months are of growing concern. Coral reefs, in particular, are already experiencing unprecedented degradation worldwide due in part to infectious disease outbreaks and bleaching episodes that are exacerbated by increasing SST. For example, Vibrio coralliilyticus, a globally distributed bacterium associated with multiple coral diseases, infects corals at temperatures above 27 °C. The mechanisms underlying this temperature-dependent pathogenicity, however, are unknown. In this study, we identify potential virulence mechanisms using whole genome sequencing of V. coralliilyticus ATCC (American Type Culture Collection) BAA-450. Furthermore, we demonstrate direct temperature regulation of numerous virulence factors using proteomic analysis and bioassays. Virulence factors involved in motility, host degradation, secretion, antimicrobial resistance and transcriptional regulation are upregulated at the higher virulent temperature of 27 °C, concurrent with phenotypic changes in motility, antibiotic resistance, hemolysis, cytotoxicity and bioluminescence. These results provide evidence that temperature regulates multiple virulence mechanisms in V. coralliilyticus, independent of abundance. The ecological and biological significance of this temperature-dependent virulence response is reinforced by climate change models that predict tropical SST to consistently exceed 27 °C during the spring, summer and fall seasons. We propose V. coralliilyticus as a model Gram-negative bacterium to study temperature-dependent pathogenicity in Vibrio-related diseases. VL - 6 SN - 1751-7362 ER - TY - JOUR T1 - Transcriptional Regulation Via TF-Modifying Enzymes: An Integrative Model-Based Analysis JF - Nucleic Acids ResearchNucl. Acids Res.Nucleic Acids ResearchNucl. Acids Res. Y1 - 2011 A1 - Everett, Logan J. A1 - Jensen, Shane T. A1 - Sridhar Hannenhalli AB - Transcription factor activity is largely regulated through post-translational modification. Here, we report the first integrative model of transcription that includes both interactions between transcription factors and promoters, and between transcription factors and modifying enzymes. Simulations indicate that our method is robust against noise. We validated our tool on a well-studied stress response network in yeast and on a STAT1-mediated regulatory network in human B cells. Our work represents a significant step toward a comprehensive model of gene transcription. VL - 39 SN - 0305-1048, 1362-4962 ER - TY - JOUR T1 - Tackling the widespread and critical impact of batch effects in high-throughput data JF - Nature reviews. GeneticsNature reviews. Genetics Y1 - 2010 A1 - Leek, Jeffrey T. A1 - Scharpf, Robert B. A1 - Héctor Corrada Bravo A1 - Simcha, David A1 - Langmead, Benjamin A1 - Johnson, W. Evan A1 - Geman, Donald A1 - Baggerly, Keith A1 - Irizarry, Rafael A. KW - biotechnology KW - Computational Biology KW - Genomics KW - Oligonucleotide Array Sequence Analysis KW - Periodicals as Topic KW - Research Design KW - Sequence Analysis, DNA AB - High-throughput technologies are widely used, for example to assay genetic variants, gene and protein expression, and epigenetic modifications. One often overlooked complication with such studies is batch effects, which occur because measurements are affected by laboratory conditions, reagent lots and personnel differences. This becomes a major problem when batch effects are correlated with an outcome of interest and lead to incorrect conclusions. Using both published studies and our own analyses, we argue that batch effects (as well as other technical and biological artefacts) are widespread and critical to address. We review experimental and computational approaches for doing so. VL - 11 N1 - http://www.ncbi.nlm.nih.gov/pubmed/20838408?dopt=Abstract ER - TY - JOUR T1 - Three genomes from the phylum Acidobacteria provide insight into the lifestyles of these microorganisms in soils. JF - Appl Environ Microbiol Y1 - 2009 A1 - Ward, Naomi L A1 - Challacombe, Jean F A1 - Janssen, Peter H A1 - Henrissat, Bernard A1 - Coutinho, Pedro M A1 - Wu, Martin A1 - Xie, Gary A1 - Haft, Daniel H A1 - Sait, Michelle A1 - Badger, Jonathan A1 - Barabote, Ravi D A1 - Bradley, Brent A1 - Brettin, Thomas S A1 - Brinkac, Lauren M A1 - Bruce, David A1 - Creasy, Todd A1 - Daugherty, Sean C A1 - Davidsen, Tanja M A1 - DeBoy, Robert T A1 - Detter, J Chris A1 - Dodson, Robert J A1 - Durkin, A Scott A1 - Ganapathy, Anuradha A1 - Gwinn-Giglio, Michelle A1 - Han, Cliff S A1 - Khouri, Hoda A1 - Kiss, Hajnalka A1 - Kothari, Sagar P A1 - Madupu, Ramana A1 - Nelson, Karen E A1 - Nelson, William C A1 - Paulsen, Ian A1 - Penn, Kevin A1 - Ren, Qinghu A1 - Rosovitz, M J A1 - Selengut, Jeremy D A1 - Shrivastava, Susmita A1 - Sullivan, Steven A A1 - Tapia, Roxanne A1 - Thompson, L Sue A1 - Watkins, Kisha L A1 - Yang, Qi A1 - Yu, Chunhui A1 - Zafar, Nikhat A1 - Zhou, Liwei A1 - Kuske, Cheryl R KW - Anti-Bacterial Agents KW - bacteria KW - Biological Transport KW - Carbohydrate Metabolism KW - Cyanobacteria KW - DNA, Bacterial KW - Fungi KW - Genome, Bacterial KW - Macrolides KW - Molecular Sequence Data KW - Nitrogen KW - Phylogeny KW - Proteobacteria KW - Sequence Analysis, DNA KW - Sequence Homology KW - Soil Microbiology AB -

The complete genomes of three strains from the phylum Acidobacteria were compared. Phylogenetic analysis placed them as a unique phylum. They share genomic traits with members of the Proteobacteria, the Cyanobacteria, and the Fungi. The three strains appear to be versatile heterotrophs. Genomic and culture traits indicate the use of carbon sources that span simple sugars to more complex substrates such as hemicellulose, cellulose, and chitin. The genomes encode low-specificity major facilitator superfamily transporters and high-affinity ABC transporters for sugars, suggesting that they are best suited to low-nutrient conditions. They appear capable of nitrate and nitrite reduction but not N(2) fixation or denitrification. The genomes contained numerous genes that encode siderophore receptors, but no evidence of siderophore production was found, suggesting that they may obtain iron via interaction with other microorganisms. The presence of cellulose synthesis genes and a large class of novel high-molecular-weight excreted proteins suggests potential traits for desiccation resistance, biofilm formation, and/or contribution to soil structure. Polyketide synthase and macrolide glycosylation genes suggest the production of novel antimicrobial compounds. Genes that encode a variety of novel proteins were also identified. The abundance of acidobacteria in soils worldwide and the breadth of potential carbon use by the sequenced strains suggest significant and previously unrecognized contributions to the terrestrial carbon cycle. Combining our genomic evidence with available culture traits, we postulate that cells of these isolates are long-lived, divide slowly, exhibit slow metabolic rates under low-nutrient conditions, and are well equipped to tolerate fluctuations in soil hydration.

VL - 75 CP - 7 M3 - 10.1128/AEM.02294-08 ER - TY - JOUR T1 - Three genomes from the phylum Acidobacteria provide insight into the lifestyles of these microorganisms in soils JF - Applied and environmental microbiologyApplied and environmental microbiology Y1 - 2009 A1 - Ward, Naomi L. A1 - Challacombe, Jean F. A1 - Janssen, Peter H. A1 - Henrissat, Bernard A1 - Coutinho, Pedro M. A1 - Wu, Martin A1 - Xie, Gary A1 - Haft, Daniel H. A1 - Sait, Michelle A1 - Badger, Jonathan A1 - Barabote, Ravi D. A1 - Bradley, Brent A1 - Brettin, Thomas S. A1 - Brinkac, Lauren M. A1 - Bruce, David A1 - Creasy, Todd A1 - Daugherty, Sean C. A1 - Davidsen, Tanja M. A1 - DeBoy, Robert T. A1 - Detter, J. Chris A1 - Dodson, Robert J. A1 - Durkin, A. Scott A1 - Ganapathy, Anuradha A1 - Gwinn-Giglio, Michelle A1 - Han, Cliff S. A1 - Khouri, Hoda A1 - Kiss, Hajnalka A1 - Kothari, Sagar P. A1 - Madupu, Ramana A1 - Nelson, Karen E. A1 - Nelson, William C. A1 - Paulsen, Ian A1 - Penn, Kevin A1 - Ren, Qinghu A1 - Rosovitz, M. J. A1 - J. Selengut A1 - Shrivastava, Susmita A1 - Sullivan, Steven A. A1 - Tapia, Roxanne A1 - Thompson, L. Sue A1 - Watkins, Kisha L. A1 - Yang, Qi A1 - Yu, Chunhui A1 - Zafar, Nikhat A1 - Zhou, Liwei A1 - Kuske, Cheryl R. KW - Anti-Bacterial Agents KW - bacteria KW - Biological Transport KW - Carbohydrate Metabolism KW - Cyanobacteria KW - DNA, Bacterial KW - Fungi KW - Genome, Bacterial KW - Macrolides KW - Molecular Sequence Data KW - Nitrogen KW - Phylogeny KW - Proteobacteria KW - Sequence Analysis, DNA KW - Sequence Homology KW - Soil Microbiology AB - The complete genomes of three strains from the phylum Acidobacteria were compared. Phylogenetic analysis placed them as a unique phylum. They share genomic traits with members of the Proteobacteria, the Cyanobacteria, and the Fungi. The three strains appear to be versatile heterotrophs. Genomic and culture traits indicate the use of carbon sources that span simple sugars to more complex substrates such as hemicellulose, cellulose, and chitin. The genomes encode low-specificity major facilitator superfamily transporters and high-affinity ABC transporters for sugars, suggesting that they are best suited to low-nutrient conditions. They appear capable of nitrate and nitrite reduction but not N(2) fixation or denitrification. The genomes contained numerous genes that encode siderophore receptors, but no evidence of siderophore production was found, suggesting that they may obtain iron via interaction with other microorganisms. The presence of cellulose synthesis genes and a large class of novel high-molecular-weight excreted proteins suggests potential traits for desiccation resistance, biofilm formation, and/or contribution to soil structure. Polyketide synthase and macrolide glycosylation genes suggest the production of novel antimicrobial compounds. Genes that encode a variety of novel proteins were also identified. The abundance of acidobacteria in soils worldwide and the breadth of potential carbon use by the sequenced strains suggest significant and previously unrecognized contributions to the terrestrial carbon cycle. Combining our genomic evidence with available culture traits, we postulate that cells of these isolates are long-lived, divide slowly, exhibit slow metabolic rates under low-nutrient conditions, and are well equipped to tolerate fluctuations in soil hydration. VL - 75 N1 - http://www.ncbi.nlm.nih.gov/pubmed/19201974?dopt=Abstract ER - TY - JOUR T1 - Toward reconstructing the evolution of advanced moths and butterflies (Lepidoptera: Ditrysia): an initial molecular study JF - BMC Evol BiolBMC Evol Biol Y1 - 2009 A1 - Regier, J. C. A1 - Zwick, A. A1 - Michael P. Cummings A1 - Kawahara, A. Y. A1 - Cho, S. A1 - Weller, S. A1 - Roe, A. A1 - Baixeras, J. A1 - Brown, J. W. A1 - Parr, C. A1 - Davis, D. R. A1 - Epstein, M. A1 - Hallwachs, W. A1 - Hausmann, A. A1 - Janzen, D. H. A1 - Kitching, I. J. A1 - Solis, M. A. A1 - Yen, S. H. A1 - Adam L. Bazinet A1 - Mitter, C. AB - BACKGROUND: In the mega-diverse insect order Lepidoptera (butterflies and moths; 165,000 described species), deeper relationships are little understood within the clade Ditrysia, to which 98% of the species belong. To begin addressing this problem, we tested the ability of five protein-coding nuclear genes (6.7 kb total), and character subsets therein, to resolve relationships among 123 species representing 27 (of 33) superfamilies and 55 (of 100) families of Ditrysia under maximum likelihood analysis. RESULTS: Our trees show broad concordance with previous morphological hypotheses of ditrysian phylogeny, although most relationships among superfamilies are weakly supported. There are also notable surprises, such as a consistently closer relationship of Pyraloidea than of butterflies to most Macrolepidoptera. Monophyly is significantly rejected by one or more character sets for the putative clades Macrolepidoptera as currently defined (P < 0.05) and Macrolepidoptera excluding Noctuoidea and Bombycoidea sensu lato (P < or = 0.005), and nearly so for the superfamily Drepanoidea as currently defined (P < 0.08). Superfamilies are typically recovered or nearly so, but usually without strong support. Relationships within superfamilies and families, however, are often robustly resolved. We provide some of the first strong molecular evidence on deeper splits within Pyraloidea, Tortricoidea, Geometroidea, Noctuoidea and others.Separate analyses of mostly synonymous versus non-synonymous character sets revealed notable differences (though not strong conflict), including a marked influence of compositional heterogeneity on apparent signal in the third codon position (nt3). As available model partitioning methods cannot correct for this variation, we assessed overall phylogeny resolution through separate examination of trees from each character set. Exploration of "tree space" with GARLI, using grid computing, showed that hundreds of searches are typically needed to find the best-feasible phylogeny estimate for these data. CONCLUSION: Our results (a) corroborate the broad outlines of the current working phylogenetic hypothesis for Ditrysia, (b) demonstrate that some prominent features of that hypothesis, including the position of the butterflies, need revision, and (c) resolve the majority of family and subfamily relationships within superfamilies as thus far sampled. Much further gene and taxon sampling will be needed, however, to strongly resolve individual deeper nodes. VL - 9 ER - TY - JOUR T1 - Two alternatively spliced isoforms of the Arabidopsis SR45 protein have distinct roles during normal plant development. JF - Plant Physiol Y1 - 2009 A1 - Zhang, Xiao-Ning A1 - Mount, Stephen M KW - Alternative Splicing KW - Amino Acid Sequence KW - Arabidopsis KW - Arabidopsis Proteins KW - Carrier Proteins KW - Flowers KW - Molecular Sequence Data KW - Mutation KW - Plant Roots KW - Protein Isoforms KW - Ribonucleoproteins KW - RNA-Binding Proteins KW - sequence alignment AB -

The serine-arginine-rich (SR) proteins constitute a conserved family of pre-mRNA splicing factors. In Arabidopsis (Arabidopsis thaliana), they are encoded by 19 genes, most of which are themselves alternatively spliced. In the case of SR45, the use of alternative 3' splice sites 21 nucleotides apart generates two alternatively spliced isoforms. Isoform 1 (SR45.1) has an insertion relative to isoform 2 (SR45.2) that replaces a single arginine with eight amino acids (TSPQRKTG). The biological implications of SR45 alternative splicing have been unclear. A previously described loss-of-function mutant affecting both isoforms, sr45-1, shows several developmental defects, including defects in petal development and root growth. We found that the SR45 promoter is highly active in regions with actively growing and dividing cells. We also tested the ability of each SR45 isoform to complement the sr45-1 mutant by overexpression of isoform-specific green fluorescent protein (GFP) fusion proteins. As expected, transgenic plants overexpressing either isoform displayed both nuclear speckles and GFP fluorescence throughout the nucleoplasm. We found that SR45.1-GFP complements the flower petal phenotype, but not the root growth phenotype. Conversely, SR45.2-GFP complements root growth but not floral morphology. Mutation of a predicted phosphorylation site within the alternatively spliced segment, SR45.1-S219A-GFP, does not affect complementation. However, a double mutation affecting both serine-219 and the adjacent threonine-218 (SR45.1-T218A + S219A-GFP) behaves like isoform 2, complementing the root but not the floral phenotype. In conclusion, our study provides evidence that the two alternatively spliced isoforms of SR45 have distinct biological functions.

VL - 150 CP - 3 M3 - 10.1104/pp.109.138180 ER - TY - JOUR T1 - Transesterification activity of a novel lipase from Acinetobacter venetianus RAG-1 JF - Antonie van LeeuwenhoekAntonie van Leeuwenhoek Y1 - 2008 A1 - Snellman, E. A. A1 - Rita R. Colwell AB - Transesterification activity and the industrial potential of a novel lipase prepared from Acinetobacter ventiatus RAG-1 were evaluated. Purified lipase samples were dialyzed against pH 9.0 buffer in a single optimization step prior to lyophilization. The enzyme and organic phase were pre-equilibrated (separately) to the same thermodynamic water activities (a w) ranging from a w 0.33 to 0.97. Production of 1-octyl butyrate by lipase-catalyzed transesterification of vinyl butyrate with 1-octanol in hexane was monitored by gas chromatography. Production of 1-octyl butyrate and initial rate of reaction depended on water activity. Product synthesis and rate of transesterification increased sharply with increase from a w 0.33 to 0.55. Highest product concentration (218 mM) and rate of reaction (18.7 μmol h−1 · 10 μg protein) were measured at a w 0.86. Transesterification activity in hexane represented 32% of comparable hydrolytic activity in aqueous buffer. VL - 94 ER - TY - JOUR T1 - A Tutorial of the Poisson Random Field Model in Population Genetics JF - Advances in BioinformaticsAdvances in Bioinformatics Y1 - 2008 A1 - Sethupathy, Praveen A1 - Sridhar Hannenhalli AB - Population genetics is the study of allele frequency changes driven by various evolutionary forces such as mutation, natural selection, and random genetic drift. Although natural selection is widely recognized as a bona-fide phenomenon, the extent to which it drives evolution continues to remain unclear and controversial. Various qualitative techniques, or so-called “tests of neutrality”, have been introduced to detect signatures of natural selection. A decade and a half ago, Stanley Sawyer and Daniel Hartl provided a mathematical framework, referred to as the Poisson random field (PRF), with which to determine quantitatively the intensity of selection on a particular gene or genomic region. The recent availability of large-scale genetic polymorphism data has sparked widespread interest in genome-wide investigations of natural selection. To that end, the original PRF model is of particular interest for geneticists and evolutionary genomicists. In this article, we will provide a tutorial of the mathematical derivation of the original Sawyer and Hartl PRF model. VL - 2008 SN - 1687-8027, 1687-8035 ER - TY - JOUR T1 - TIGRFAMs and Genome Properties: tools for the assignment of molecular function and biological process in prokaryotic genomes JF - Nucleic acids researchNucleic Acids Research Y1 - 2007 A1 - J. Selengut A1 - Haft, Daniel H. A1 - Davidsen, Tanja A1 - Ganapathy, Anurhada A1 - Gwinn-Giglio, Michelle A1 - Nelson, William C. A1 - Richter, R. Alexander A1 - White, Owen KW - Archaeal Proteins KW - Bacterial Proteins KW - Databases, Protein KW - Genome, Bacterial KW - Genomics KW - Internet KW - Phylogeny KW - software KW - User-Computer Interface AB - TIGRFAMs is a collection of protein family definitions built to aid in high-throughput annotation of specific protein functions. Each family is based on a hidden Markov model (HMM), where both cutoff scores and membership in the seed alignment are chosen so that the HMMs can classify numerous proteins according to their specific molecular functions. Most TIGRFAMs models describe 'equivalog' families, where both orthology and lateral gene transfer may be part of the evolutionary history, but where a single molecular function has been conserved. The Genome Properties system contains a queriable set of metabolic reconstructions, genome metrics and extractions of information from the scientific literature. Its genome-by-genome assertions of whether or not specific structures, pathways or systems are present provide high-level conceptual descriptions of genomic content. These assertions enable comparative genomics, provide a meaningful biological context to aid in manual annotation, support assignments of Gene Ontology (GO) biological process terms and help validate HMM-based predictions of protein function. The Genome Properties system is particularly useful as a generator of phylogenetic profiles, through which new protein family functions may be discovered. The TIGRFAMs and Genome Properties systems can be accessed at http://www.tigr.org/TIGRFAMs and http://www.tigr.org/Genome_Properties. VL - 35 N1 - http://www.ncbi.nlm.nih.gov/pubmed/17151080?dopt=Abstract ER - TY - JOUR T1 - TREMOR—a tool for retrieving transcriptional modules by incorporating motif covariance JF - Nucleic acids researchNucleic Acids Research Y1 - 2007 A1 - Singh, L. N. A1 - Wang, L. S. A1 - Sridhar Hannenhalli PB - Oxford Univ Press VL - 35 ER - TY - JOUR T1 - Toxigenic Vibrio Cholerae in the Aquatic Environment of Mathbaria, Bangladesh JF - Applied and Environmental MicrobiologyAppl. Environ. Microbiol.Applied and Environmental MicrobiologyAppl. Environ. Microbiol. Y1 - 2006 A1 - Alam, Munirul A1 - Sultana, Marzia A1 - Nair, G. Balakrish A1 - Sack, R. Bradley A1 - Sack, David A. A1 - Siddique, A. K. A1 - Ali, Afsar A1 - Huq, Anwar A1 - Rita R. Colwell AB - Toxigenic Vibrio cholerae, rarely isolated from the aquatic environment between cholera epidemics, can be detected in what is now understood to be a dormant stage, i.e., viable but nonculturable when standard bacteriological methods are used. In the research reported here, biofilms have proved to be a source of culturable V. cholerae, even in nonepidemic periods. Biweekly environmental surveillance for V. cholerae was carried out in Mathbaria, an area of cholera endemicity adjacent to the Bay of Bengal, with the focus on V. cholerae O1 and O139 Bengal. A total of 297 samples of water, phytoplankton, and zooplankton were collected between March and December 2004, yielding eight V. cholerae O1 and four O139 Bengal isolates. A combination of culture methods, multiplex-PCR, and direct fluorescent antibody (DFA) counting revealed the Mathbaria aquatic environment to be a reservoir for V. cholerae O1 and O139 Bengal. DFA results showed significant clumping of the bacteria during the interepidemic period for cholera, and the fluorescent micrographs revealed large numbers of V. cholerae O1 in thin films of exopolysaccharides (biofilm). A similar clumping of V. cholerae O1 was also observed in samples collected from Matlab, Bangladesh, where cholera also is endemic. Thus, the results of the study provided in situ evidence for V. cholerae O1 and O139 in the aquatic environment, predominantly as viable but nonculturable cells and culturable cells in biofilm consortia. The biofilm community is concluded to be an additional reservoir of cholera bacteria in the aquatic environment between seasonal epidemics of cholera in Bangladesh. VL - 72 SN - 0099-2240, 1098-5336 ER - TY - JOUR T1 - Transcriptional Genomics Associates FOX Transcription Factors With Human Heart Failure JF - CirculationCirculation Y1 - 2006 A1 - Sridhar Hannenhalli A1 - Putt, Mary E. A1 - Gilmore, Joan M. A1 - Wang, Junwen A1 - Parmacek, Michael S. A1 - Epstein, Jonathan A. A1 - Morrisey, Edward E. A1 - Margulies, Kenneth B. A1 - Cappola, Thomas P. AB - Background— Specific transcription factors (TFs) modulate cardiac gene expression in murine models of heart failure, but their relevance in human subjects remains untested. We developed and applied a computational approach called transcriptional genomics to test the hypothesis that a discrete set of cardiac TFs is associated with human heart failure.Methods and Results— RNA isolates from failing (n=196) and nonfailing (n=16) human hearts were hybridized with Affymetrix HU133A arrays, and differentially expressed heart failure genes were determined. TF binding sites overrepresented in the −5-kb promoter sequences of these heart failure genes were then determined with the use of public genome sequence databases. Binding sites for TFs identified in murine heart failure models (MEF2, NKX, NF-AT, and GATA) were significantly overrepresented in promoters of human heart failure genes (P<0.002; false discovery rate 2% to 4%). In addition, binding sites for FOX TFs showed substantial overrepresentation in both advanced human and early murine heart failure (P<0.002 and false discovery rate <4% for each). A role for FOX TFs was supported further by expression of FOXC1, C2, P1, P4, and O1A in failing human cardiac myocytes at levels similar to established hypertrophic TFs and by abundant FOXP1 protein in failing human cardiac myocyte nuclei.Conclusions— Our results provide the first evidence that specific TFs identified in murine models (MEF2, NKX, NFAT, and GATA) are associated with human heart failure. Moreover, these data implicate specific members of the FOX family of TFs (FOXC1, C2, P1, P4, and O1A) not previously suggested in heart failure pathogenesis. These findings provide a crucial link between animal models and human disease and suggest a specific role for FOX signaling in modulating the hypertrophic response of the heart to stress in humans. VL - 114 ER - TY - JOUR T1 - The Trypanosoma cruzi L1Tc and NARTc non-LTR retrotransposons show relative site specificity for insertion. JF - Mol Biol Evol Y1 - 2006 A1 - Bringaud, Frederic A1 - Bartholomeu, Daniella C A1 - Blandin, Gaëlle A1 - Delcher, Arthur A1 - Baltz, Théo A1 - el-Sayed, Najib M A A1 - Ghedin, Elodie KW - Animals KW - DNA, Protozoan KW - DNA-(Apurinic or Apyrimidinic Site) Lyase KW - Mutagenesis, Insertional KW - Retroelements KW - Sequence Deletion KW - Trypanosoma cruzi AB -

The trypanosomatid protozoan Trypanosoma cruzi contains long autonomous (L1Tc) and short nonautonomous (NARTc) non-long terminal repeat retrotransposons. NARTc (0.25 kb) probably derived from L1Tc (4.9 kb) by 3'-deletion. It has been proposed that their apparent random distribution in the genome is related to the L1Tc-encoded apurinic/apyrimidinic endonuclease (APE) activity, which repairs modified residues. To address this question we used the T. cruzi (CL-Brener strain) genome data to analyze the distribution of all the L1Tc/NARTc elements present in contigs larger than 10 kb. This data set, which represents 0.91x sequence coverage of the haploid nuclear genome ( approximately 55 Mb), contains 419 elements, including 112 full-length L1Tc elements (14 of which are potentially functional) and 84 full-length NARTc. Approximately half of the full-length elements are flanked by a target site duplication, most of them (87%) are 12 bp long. Statistical analyses of sequences flanking the full-length elements show the same highly conserved pattern upstream of both the L1Tc and NARTc retrotransposons. The two most conserved residues are a guanine and an adenine, which flank the site where first-strand cleavage is performed by the element-encoded endonuclease activity. This analysis clearly indicates that the L1Tc and NARTc elements display relative site specificity for insertion, which suggests that the APE activity is not responsible for first-strand cleavage of the target site.

VL - 23 CP - 2 M3 - 10.1093/molbev/msj046 ER - TY - JOUR T1 - The Trypanosoma cruzi L1Tc and NARTc non-LTR retrotransposons show relative site specificity for insertion JF - Molecular biology and evolutionMolecular biology and evolution Y1 - 2006 A1 - Bringaud, F. A1 - Bartholomeu, D. C. A1 - Blandin, G. A1 - Delcher, A. A1 - Baltz, T. A1 - Najib M. El‐Sayed A1 - Ghedin, E. VL - 23 ER - TY - JOUR T1 - Trypanosoma cruzi mitochondrial maxicircles display species- and strain-specific variation and a conserved element in the non-coding region JF - BMC GenomicsBMC Genomics Y1 - 2006 A1 - Westenberger, Scott A1 - Cerqueira, Gustavo A1 - Najib M. El‐Sayed A1 - Zingales, Bianca A1 - Campbell, David A1 - Sturm, Nancy AB - BACKGROUND:The mitochondrial DNA of kinetoplastid flagellates is distinctive in the eukaryotic world due to its massive size, complex form and large sequence content. Comprised of catenated maxicircles that contain rRNA and protein-coding genes and thousands of heterogeneous minicircles encoding small guide RNAs, the kinetoplast network has evolved along with an extreme form of mRNA processing in the form of uridine insertion and deletion RNA editing. Many maxicircle-encoded mRNAs cannot be translated without this post-transcriptional sequence modification.RESULTS:We present the complete sequence and annotation of the Trypanosoma cruzi maxicircles for the CL Brener and Esmeraldo strains. Gene order is syntenic with Trypanosoma brucei and Leishmania tarentolae maxicircles. The non-coding components have strain-specific repetitive regions and a variable region that is unique for each strain with the exception of a conserved sequence element that may serve as an origin of replication, but shows no sequence identity with L. tarentolae or T. brucei. Alternative assemblies of the variable region demonstrate intra-strain heterogeneity of the maxicircle population. The extent of mRNA editing required for particular genes approximates that seen in T. brucei. Extensively edited genes were more divergent among the genera than non-edited and rRNA genes. Esmeraldo contains a unique 236-bp deletion that removes the 5'-ends of ND4 and CR4 and the intergenic region. Esmeraldo shows additional insertions and deletions outside of areas edited in other species in ND5, MURF1, and MURF2, while CL Brener has a distinct insertion in MURF2.CONCLUSION:The CL Brener and Esmeraldo maxicircles represent two of three previously defined maxicircle clades and promise utility as taxonomic markers. Restoration of the disrupted reading frames might be accomplished by strain-specific RNA editing. Elements in the non-coding region may be important for replication, transcription, and anchoring of the maxicircle within the kinetoplast network. VL - 7 SN - 1471-2164 ER - TY - JOUR T1 - Trypanosoma cruzi mitochondrial maxicircles display species- and strain-specific variation and a conserved element in the non-coding region. JF - BMC Genomics Y1 - 2006 A1 - Westenberger, Scott J A1 - Cerqueira, Gustavo C A1 - El-Sayed, Najib M A1 - Zingales, Bianca A1 - Campbell, David A A1 - Sturm, Nancy R KW - Amino Acid Sequence KW - Animals KW - Animals, Inbred Strains KW - Base Composition KW - Conserved Sequence KW - DNA, Kinetoplast KW - Frameshifting, Ribosomal KW - Gene Deletion KW - Gene Order KW - Genetic Variation KW - Leishmania KW - Models, Biological KW - Molecular Sequence Data KW - Muscle Proteins KW - NADH Dehydrogenase KW - Open Reading Frames KW - Regulatory Elements, Transcriptional KW - RNA Editing KW - Sequence Homology, Amino Acid KW - Species Specificity KW - Trypanosoma brucei brucei KW - Trypanosoma cruzi KW - Ubiquitin-Protein Ligases KW - Untranslated Regions AB -

BACKGROUND: The mitochondrial DNA of kinetoplastid flagellates is distinctive in the eukaryotic world due to its massive size, complex form and large sequence content. Comprised of catenated maxicircles that contain rRNA and protein-coding genes and thousands of heterogeneous minicircles encoding small guide RNAs, the kinetoplast network has evolved along with an extreme form of mRNA processing in the form of uridine insertion and deletion RNA editing. Many maxicircle-encoded mRNAs cannot be translated without this post-transcriptional sequence modification.

RESULTS: We present the complete sequence and annotation of the Trypanosoma cruzi maxicircles for the CL Brener and Esmeraldo strains. Gene order is syntenic with Trypanosoma brucei and Leishmania tarentolae maxicircles. The non-coding components have strain-specific repetitive regions and a variable region that is unique for each strain with the exception of a conserved sequence element that may serve as an origin of replication, but shows no sequence identity with L. tarentolae or T. brucei. Alternative assemblies of the variable region demonstrate intra-strain heterogeneity of the maxicircle population. The extent of mRNA editing required for particular genes approximates that seen in T. brucei. Extensively edited genes were more divergent among the genera than non-edited and rRNA genes. Esmeraldo contains a unique 236-bp deletion that removes the 5'-ends of ND4 and CR4 and the intergenic region. Esmeraldo shows additional insertions and deletions outside of areas edited in other species in ND5, MURF1, and MURF2, while CL Brener has a distinct insertion in MURF2.

CONCLUSION: The CL Brener and Esmeraldo maxicircles represent two of three previously defined maxicircle clades and promise utility as taxonomic markers. Restoration of the disrupted reading frames might be accomplished by strain-specific RNA editing. Elements in the non-coding region may be important for replication, transcription, and anchoring of the maxicircle within the kinetoplast network.

VL - 7 M3 - 10.1186/1471-2164-7-60 ER - TY - JOUR T1 - Telomere and subtelomere of Trypanosoma cruzi chromosomes are enriched in (pseudo)genes of retrotransposon hot spot and trans-sialidase-like gene families: the origins of T. cruzi telomeres. JF - Gene Y1 - 2005 A1 - Kim, Dong A1 - Chiurillo, Miguel Angel A1 - El-Sayed, Najib A1 - Jones, Kristin A1 - Santos, Márcia R M A1 - Porcile, Patricio E A1 - Andersson, Björn A1 - Myler, Peter A1 - da Silveira, Jose Franco A1 - Ramírez, José Luis KW - Amino Acid Sequence KW - Animals KW - Base Sequence KW - Chromosomes KW - Chromosomes, Artificial, Bacterial KW - DNA, Protozoan KW - Genes, Protozoan KW - Glycoproteins KW - Molecular Sequence Data KW - Multigene Family KW - Neuraminidase KW - Pseudogenes KW - Retroelements KW - Sequence Homology, Amino Acid KW - Sequence Homology, Nucleic Acid KW - Telomere KW - Trypanosoma cruzi AB -

Here, we sequenced two large telomeric regions obtained from the pathogen protozoan Trypanosoma cruzi. These sequences, together with in silico assembled contigs, allowed us to establish the general features of telomeres and subtelomeres of this parasite. Our findings can be summarized as follows: We confirmed the presence of two types of telomeric ends; subtelomeric regions appeared to be enriched in (pseudo)genes of RHS (retrotransposon hot spot), TS (trans-sialidase)-like proteins, and putative surface protein DGF-1 (dispersed gene family-1). Sequence analysis of the ts-like genes located at the telomeres suggested that T. cruzi chromosomal ends could have been the site for generation of new gp85 variants, an important adhesin molecule involved in the invasion of mammalian cells by T. cruzi. Finally, a mechanism for generation of T. cruzi telomere by chromosome breakage and telomere healing is proposed.

VL - 346 M3 - 10.1016/j.gene.2004.10.014 ER - TY - JOUR T1 - Temperature-Driven Campylobacter Seasonality in England and Wales JF - Applied and Environmental MicrobiologyAppl. Environ. Microbiol.Applied and Environmental MicrobiologyAppl. Environ. Microbiol. Y1 - 2005 A1 - Louis, Valérie R. A1 - Gillespie, Iain A. A1 - O'Brien, Sarah J. A1 - Russek-Cohen, Estelle A1 - Pearson, Andrew D. A1 - Rita R. Colwell AB - Campylobacter incidence in England and Wales between 1990 and 1999 was examined in conjunction with weather conditions. Over the 10-year interval, the average annual rate was determined to be 78.4 ± 15.0 cases per 100,000, with an upward trend. Rates were higher in males than in females, regardless of age, and highest in children less than 5 years old. Major regional differences were detected, with the highest rates in Wales and the southwest and the lowest in the southeast. The disease displayed a seasonal pattern, and increased campylobacter rates were found to be correlated with temperature. The most marked seasonal effect was observed for children under the age of 5. The seasonal pattern of campylobacter infections indicated a linkage with environmental factors rather than food sources. Therefore, public health interventions should not be restricted to food-borne approaches, and the epidemiology of the seasonal peak in human campylobacter infections may best be understood through studies in young children. VL - 71 SN - 0099-2240, 1098-5336 ER - TY - JOUR T1 - Transcriptional profiling of the hyperthermophilic methanarchaeon Methanococcus jannaschii in response to lethal heat and non-lethal cold shock. JF - Environ Microbiol Y1 - 2005 A1 - Boonyaratanakornkit, Boonchai B A1 - Simpson, Anjana J A1 - Whitehead, Timothy A A1 - Fraser, Claire M A1 - el-Sayed, Najib M A A1 - Clark, Douglas S KW - Adaptation, Physiological KW - Archaeal Proteins KW - Cold Temperature KW - Gene Expression Profiling KW - Gene Expression Regulation, Archaeal KW - Heat-Shock Proteins KW - Hot Temperature KW - Methanococcus KW - Temperature KW - Transcription, Genetic AB -

Temperature shock of the hyperthermophilic methanarchaeon Methanococcus jannaschii from its optimal growth temperature of 85 degrees C to 65 degrees C and 95 degrees C resulted in different transcriptional responses characteristic of both the direction of shock (heat or cold shock) and whether the shock was lethal. Specific outcomes of lethal heat shock to 95 degrees C included upregulation of genes encoding chaperones, and downregulation of genes encoding subunits of the H+ transporting ATP synthase. A gene encoding an alpha subunit of a putative prefoldin was also upregulated, which may comprise a novel element in the protein processing pathway in M. jannaschii. Very different responses were observed upon cold shock to 65 degrees C. These included upregulation of a gene encoding an RNA helicase and other genes involved in transcription and translation, and upregulation of genes coding for proteases and transport proteins. Also upregulated was a gene that codes for an 18 kDa FKBP-type PPIase, which may facilitate protein folding at low temperatures. Transcriptional profiling also revealed several hypothetical proteins that respond to temperature stress conditions.

VL - 7 CP - 6 M3 - 10.1111/j.1462-2920.2005.00751.x ER - TY - JOUR T1 - Transcriptional profiling of the hyperthermophilic methanarchaeon Methanococcus jannaschii in response to lethal heat and non‐lethal cold shock JF - Environmental MicrobiologyEnvironmental Microbiology Y1 - 2005 A1 - Boonyaratanakornkit, Boonchai B. A1 - Simpson, Anjana J. A1 - Whitehead, Timothy A. A1 - Fraser, Claire M. A1 - Najib M. El‐Sayed A1 - Clark, Douglas S. AB - Temperature shock of the hyperthermophilic methanarchaeon Methanococcus jannaschii from its optimal growth temperature of 85°C to 65°C and 95°C resulted in different transcriptional responses characteristic of both the direction of shock (heat or cold shock) and whether the shock was lethal. Specific outcomes of lethal heat shock to 95°C included upregulation of genes encoding chaperones, and downregulation of genes encoding subunits of the H+ transporting ATP synthase. A gene encoding an α subunit of a putative prefoldin was also upregulated, which may comprise a novel element in the protein processing pathway in M. jannaschii. Very different responses were observed upon cold shock to 65°C. These included upregulation of a gene encoding an RNA helicase and other genes involved in transcription and translation, and upregulation of genes coding for proteases and transport proteins. Also upregulated was a gene that codes for an 18 kDa FKBP-type PPIase, which may facilitate protein folding at low temperatures. Transcriptional profiling also revealed several hypothetical proteins that respond to temperature stress conditions. VL - 7 SN - 1462-2920 ER - TY - CHAP T1 - A Tangled Bank: Reflections on the Tree of Life and Human Health T2 - Assembling the Tree of LifeAssembling the Tree of Life Y1 - 2004 A1 - Rita R. Colwell JA - Assembling the Tree of LifeAssembling the Tree of Life PB - Oxford University Press SN - 9780195172348 ER - TY - JOUR T1 - The TIGRFAMs database of protein families JF - Nucleic acids researchNucleic Acids Research Y1 - 2003 A1 - Haft, Daniel H. A1 - J. Selengut A1 - White, Owen KW - Animals KW - Databases, Protein KW - Markov chains KW - Mixed Function Oxygenases KW - Phylogeny KW - Proteins KW - Pyruvate Carboxylase KW - Sequence Homology, Amino Acid AB - TIGRFAMs is a collection of manually curated protein families consisting of hidden Markov models (HMMs), multiple sequence alignments, commentary, Gene Ontology (GO) assignments, literature references and pointers to related TIGRFAMs, Pfam and InterPro models. These models are designed to support both automated and manually curated annotation of genomes. TIGRFAMs contains models of full-length proteins and shorter regions at the levels of superfamilies, subfamilies and equivalogs, where equivalogs are sets of homologous proteins conserved with respect to function since their last common ancestor. The scope of each model is set by raising or lowering cutoff scores and choosing members of the seed alignment to group proteins sharing specific function (equivalog) or more general properties. The overall goal is to provide information with maximum utility for the annotation process. TIGRFAMs is thus complementary to Pfam, whose models typically achieve broad coverage across distant homologs but end at the boundaries of conserved structural domains. The database currently contains over 1600 protein families. TIGRFAMs is available for searching or downloading at www.tigr.org/TIGRFAMs. VL - 31 N1 - http://www.ncbi.nlm.nih.gov/pubmed/12520025?dopt=Abstract ER - TY - JOUR T1 - The transcription factor Eyes absent is a protein tyrosine phosphatase JF - NatureNature Y1 - 2003 A1 - Tootle, Tina L. A1 - Silver, Serena J. A1 - Davies, Erin L. A1 - Newman, Victoria A1 - Latek, Robert R. A1 - Mills, Ishara A. A1 - J. Selengut A1 - Parlikar, Beth E. W. A1 - Rebay, Ilaria KW - Amino Acid Motifs KW - Amino Acid Sequence KW - Animals KW - Antibodies, Phospho-Specific KW - Drosophila melanogaster KW - Drosophila Proteins KW - Embryonic Induction KW - eye KW - Eye Proteins KW - Gene Expression Regulation KW - Kinetics KW - Mice KW - Models, Molecular KW - Molecular Sequence Data KW - Mutation KW - Phosphorylation KW - Protein Conformation KW - Protein Tyrosine Phosphatases KW - Substrate Specificity KW - Transcription Factors AB - Post-translational modifications provide sensitive and flexible mechanisms to dynamically modulate protein function in response to specific signalling inputs. In the case of transcription factors, changes in phosphorylation state can influence protein stability, conformation, subcellular localization, cofactor interactions, transactivation potential and transcriptional output. Here we show that the evolutionarily conserved transcription factor Eyes absent (Eya) belongs to the phosphatase subgroup of the haloacid dehalogenase (HAD) superfamily, and propose a function for it as a non-thiol-based protein tyrosine phosphatase. Experiments performed in cultured Drosophila cells and in vitro indicate that Eyes absent has intrinsic protein tyrosine phosphatase activity and can autocatalytically dephosphorylate itself. Confirming the biological significance of this function, mutations that disrupt the phosphatase active site severely compromise the ability of Eyes absent to promote eye specification and development in Drosophila. Given the functional importance of phosphorylation-dependent modulation of transcription factor activity, this evidence for a nuclear transcriptional coactivator with intrinsic phosphatase activity suggests an unanticipated method of fine-tuning transcriptional regulation. VL - 426 N1 - http://www.ncbi.nlm.nih.gov/pubmed/14628053?dopt=Abstract ER - TY - JOUR T1 - Transcriptional regulation of protein complexes and biological pathways JF - Mammalian GenomeMammalian Genome Y1 - 2003 A1 - Sridhar Hannenhalli A1 - Levy, Samuel AB - The cis-element profile (or cis-profile) of a gene refers to the collection of transcription factor binding sites (TFBS) regulating the transcription of the gene. Underlying the various published studies that attempt to discover cis-elements in the vicinity of co-expressed genes via pattern detection algorithms, there is an implicit assumption that a correlation exists between co-expressed genes and their cis-profiles. In this study, we show that the cis-similarity, defined as the proportion of shared TFBS between two cis-element profiles, is higher for functionally linked interacting proteins as well as for members of a signal transduction pathway. A similar analysis of the enzymes catalyzing the conversion of adjacent substrates to products in a collection of metabolic pathways, did not reveal higher cis-similarity. The analysis is based on three distinct sources of publicly available data, namely, 1) the BIND database of interacting proteins, 2) known interactions in NMDAR protein complex, 3) the apoptosis pathway and nine pathways related to metabolism of cofactors and vitamins all from KEGG. Additionally, we analyze the cis-element profiles of all the genes in the glutamate receptor (GR) sub-complex of NMDAR complex to detect a set of cis-elements that occur adjacent to a majority of the genes. We show that most of the corresponding transcription factors are known to be involved in GR regulation by comparing our findings with the published biomedical literature. In addition, we were able to detect transcripts whose gene products associate with GR by searching for transcripts that share the same regulatory signals as those detected for GR. This suggests a novel computational methodology for constructing high-order gene regulatory models and detecting co-regulated gene products. VL - 14 SN - 0938-8990 ER - TY - JOUR T1 - Trypanosoma cruzi: RNA structure and post-transcriptional control of tubulin gene expression JF - Experimental ParasitologyExperimental Parasitology Y1 - 2002 A1 - Bartholomeu, Daniella C. A1 - Silva, Rosiane A. A1 - Galvão, Lucia M. C. A1 - Najib M. El‐Sayed A1 - Donelson, John E. A1 - Teixeira, Santuza M. R. AB - Changes in tubulin expression are among the biochemical and morphological adaptations that occur during the life cycle of Trypanosomatids. To investigate the mechanism responsible for the differential accumulation of tubulin mRNAs in Trypanosoma cruzi, we determine the sequences of [alpha]- and [beta]-tubulin transcripts and analyzed their expression during the life cycle of the parasite. Two [beta]-tubulin mRNAs of 1.9 and 2.3 kb were found to differ mainly by an additional 369 nucleotides at the end of the 3' untranslated region (UTR). Although their transcription rates are similar in epimastigotes and amastigotes, [alpha]- and [beta]-tubulin transcripts are 3- to 6-fold more abundant in epimastigotes than in trypomastigotes and amastigotes. Accordingly, the half-lives of [alpha]- and [beta]-tubulin mRNAs are significantly higher in epimastigotes than in amastigotes. Transient transfection experiments indicated that positive regulatory elements occur in the 3' UTR plus downstream intergenic region of the [alpha]-tubulin gene and that both positive and negative elements occur in the equivalent regions of the [beta]-tubulin gene.Index Descriptions and Abbreviations: Kinetoplastida; Trypanosoma cruzi; tubulin; gene regulation; PCR, polymerase chain reaction; UTR, untranslated region; IR, intergenic region; SL, spliced leader; BAC, bacterial artificial chromosome. VL - 102 SN - 0014-4894 ER - TY - JOUR T1 - Trypanosoma cruzi: RNA structure and post-transcriptional control of tubulin gene expression. JF - Exp Parasitol Y1 - 2002 A1 - Bartholomeu, Daniella C A1 - Silva, Rosiane A A1 - Galvão, Lucia M C A1 - el-Sayed, Najib M A A1 - Donelson, John E A1 - Teixeira, Santuza M R KW - Animals KW - Base Sequence KW - Blotting, Northern KW - DNA, Complementary KW - DNA, Protozoan KW - Gene Expression Regulation KW - Half-Life KW - Life Cycle Stages KW - Molecular Sequence Data KW - RNA Processing, Post-Transcriptional KW - RNA, Messenger KW - RNA, Protozoan KW - Transcription, Genetic KW - Transfection KW - Trypanosoma cruzi KW - Tubulin AB -

Changes in tubulin expression are among the biochemical and morphological adaptations that occur during the life cycle of Trypanosomatids. To investigate the mechanism responsible for the differential accumulation of tubulin mRNAs in Trypanosoma cruzi, we determine the sequences of alpha- and beta-tubulin transcripts and analyzed their expression during the life cycle of the parasite. Two beta-tubulin mRNAs of 1.9 and 2.3 kb were found to differ mainly by an additional 369 nucleotides at the end of the 3' untranslated region (UTR). Although their transcription rates are similar in epimastigotes and amastigotes, alpha- and beta-tubulin transcripts are 3- to 6-fold more abundant in epimastigotes than in trypomastigotes and amastigotes. Accordingly, the half-lives of alpha- and beta-tubulin mRNAs are significantly higher in epimastigotes than in amastigotes. Transient transfection experiments indicated that positive regulatory elements occur in the 3' UTR plus downstream intergenic region of the alpha-tubulin gene and that both positive and negative elements occur in the equivalent regions of the beta-tubulin gene.

VL - 102 CP - 3-4 ER - TY - JOUR T1 - Transforming cabbage into turnip: polynomial algorithm for sorting signed permutations by reversals JF - J. ACMJ. ACM Y1 - 1999 A1 - Sridhar Hannenhalli A1 - Pevzner, Pavel A. KW - Computational Biology KW - Genetics AB - Genomes frequently evolve by reversals &rgr;(i,j) that transform a gene order &pgr;1 … &pgr;i&pgr;i+1 … &pgr;j-1&pgr;j … &pgr;n into &pgr;1 … &pgr;i&pgr;j-1 … &pgr;i+1&pgr;j … &pgr;n. Reversal distance between permutations &pgr; and &sgr;is the minimum number of reversals to transform &pgr; into &Agr;. Analysis of genome rearrangements in molecular biology started in the late 1930's, when Dobzhansky and Sturtevant published a milestone paper presenting a rearrangement scenario with 17 inversions between the species of Drosophilia. Analysis of genomes evolving by inversions leads to a combinatorial problem of sorting by reversals studied in detail recently. We study sorting of signed permutations by reversals, a problem that adequately models rearrangements in a small genomes like chloroplast or mitochondrial DNA. The previously suggested approximation algorithms for sorting signed permutations by reversals compute the reversal distance between permutations with an astonishing accuracy for both simulated and biological data. We prove a duality theorem explaining this intriguing performance and show that there exists a “hidden” parameter that allows one to compute the reversal distance between signed permutations in polynomial time. VL - 46 SN - 0004-5411 ER - TY - JOUR T1 - Trends in the early careers of life scientists - Preface and executive summary JF - Mol Biol CellMol Biol Cell Y1 - 1998 A1 - Tilghman, S. A1 - Astin, H. S. A1 - Brinkley, W. A1 - Chilton, M. D. A1 - Michael P. Cummings A1 - Ehrenberg, R. G. A1 - Fox, M. F. A1 - Glenn, K. A1 - Green, P. J. A1 - Hans, S. A1 - Kelman, A. A1 - LaPidus, J. A1 - Levin, B. A1 - McIntosh, J. R. A1 - Riecken, H. A1 - Stephen, P. E. VL - 9 ER - TY - JOUR T1 - Testing simple polygons JF - Computational GeometryComputational Geometry Y1 - 1997 A1 - Arkin, Esther M. A1 - Belleville, Patrice A1 - Mitchell, Joseph S. B. A1 - Mount, Dave A1 - Romanik, Kathleen A1 - Salzberg, Steven A1 - Souvaine, Diane KW - probing KW - Testing KW - Verifying AB - We consider the problem of verifying a simple polygon in the plane using “test points”. A test point is a geometric probe that takes as input a point in Euclidean space, and returns “+” if the point is inside the object being probed or “−” if it is outside. A verification procedure takes as input a description of a target object, including its location and orientation, and it produces a set of test points that are used to verify whether a test object matches the description. We give a procedure for verifying an n-sided, non-degenerate, simple target polygon using 5n test points. This testing strategy works even if the test polygon has n + 1 vertices, and we show a lower bound of 3n + 1 test points for this case. We also give algorithms using O(n) test points for simple polygons that may be degenerate and for test polygons that may have up to n + 2 vertices. All of these algorithms work for polygons with holes. We also discuss extensions of our results to higher dimensions. VL - 8 SN - 0925-7721 ER - TY - Generic T1 - To cut… or not to cut (applications of comparative physical maps in molecular evolution) T2 - Proceedings of the seventh annual ACM-SIAM symposium on Discrete algorithms Y1 - 1996 A1 - Sridhar Hannenhalli A1 - Pevzner, Pavel JA - Proceedings of the seventh annual ACM-SIAM symposium on Discrete algorithms T3 - SODA '96 PB - Society for Industrial and Applied Mathematics CY - Philadelphia, PA, USA SN - 0-89871-366-8 ER - TY - CHAP T1 - Towards a computational theory of genome rearrangements T2 - Computer Science TodayComputer Science Today Y1 - 1995 A1 - Sridhar Hannenhalli A1 - Pevzner, Pavel ED - van Leeuwen, Jan AB - Analysis of genome rearrangements in molecular biology started in the late 1930's, when Dobzhansky and Sturtevant published a milestone paper presenting a rearrangement scenario with 17 inversions for the species of Drosophila. However, until recently there were no computer science results allowing a biologist to analyze genome rearrangements. The paper describes combinatorial problems motivated by genome rearrangements, surveys recently developed algorithms for genomic sequence comparison and presents applications of these algorithms to analyze rearrangements in herpes viruses, plant organelles, and mammalian chromosomes. JA - Computer Science TodayComputer Science Today T3 - Lecture Notes in Computer Science PB - Springer Berlin / Heidelberg VL - 1000 SN - 978-3-540-60105-0 ER - TY - Generic T1 - Transforming cabbage into turnip: polynomial algorithm for sorting signed permutations by reversals T2 - Proceedings of the twenty-seventh annual ACM symposium on Theory of computing Y1 - 1995 A1 - Sridhar Hannenhalli A1 - Pevzner, Pavel JA - Proceedings of the twenty-seventh annual ACM symposium on Theory of computing T3 - STOC '95 PB - ACM CY - New York, NY, USA SN - 0-89791-718-9 ER - TY - THES T1 - Transforming men into mice (a computational theory of genome rearrangements) Y1 - 1995 A1 - Sridhar Hannenhalli PB - The Pennsylvania State University ER - TY - Generic T1 - Transforming men into mice (polynomial algorithm for genomic distance problem) T2 - Foundations of Computer Science, Annual IEEE Symposium on Y1 - 1995 A1 - Sridhar Hannenhalli A1 - Pevzner, P. A. KW - biology computing KW - combinatorial properties KW - comparative physical mapping data KW - computable parameters KW - duality (mathematics) KW - duality theorem KW - evolution (biological) KW - Genetics KW - genome rearrangement algorithm KW - genomic distance problem KW - genomic rearrangements KW - human-mouse evolution KW - mammalian evolution KW - multi chromosomal genomes KW - parsimonious rearrangement scenarios KW - pattern matching KW - polynomial algorithm KW - polynomial time algorithm KW - set theory KW - sorting KW - string matching KW - strings KW - zoo fish AB - Many people believe that transformations of humans into mice happen only in fairy tales. However, despite some differences in appearance and habits, men and mice are genetically very similar. In the pioneering paper, J.H. Nadeau and B.A. Taylor (1984) estimated that surprisingly few genomic rearrangements (178/spl plusmn/39) happened since the divergence of human and mouse 80 million years ago. However, their analysis is nonconstructive and no rearrangement scenario for human-mouse evolution has been suggested yet. The problem is complicated by the fact that rearrangements in multi chromosomal genomes include inversions, translocations, fusions and fissions of chromosomes, a rather complex set of operations. As a result, at first glance, a polynomial algorithm for the genomic distance problem with all these operations looks almost as improbable as the transformation of a (real) man into a (real) mouse. We prove a duality theorem which expresses the genomic distance in terms of easily computable parameters reflecting different combinatorial properties of sets of strings. This theorem leads to a polynomial time algorithm for computing most parsimonious rearrangement scenarios. Based on this result and the latest comparative physical mapping data we have constructed a scenario of human-mouse evolution with 131 reversals/translocaitons/fusions/fissions. A combination of the genome rearrangement algorithm with the recently proposed experimental technique called ZOO FISH suggests a new constructive approach to the 100 year old problem of reconstructing mammalian evolution. JA - Foundations of Computer Science, Annual IEEE Symposium on PB - IEEE Computer Society CY - Los Alamitos, CA, USA ER - TY - JOUR T1 - Transmission patterns of eukaryotic transposable elements - arguments for and against horizontal transfer JF - Trends Ecol EvolTrends Ecol Evol Y1 - 1994 A1 - Michael P. Cummings AB - Recent studies have demonstrated that several classes of transposable elements are widely distributed within eukaryotes. Horizontal transmission of these transposable elements has often been invoked in order to explain the observed variation and relationships within and between species. These same patterns of variation and relationships, however, may originate from processes that do not involve the lateral transfer of genetic material across species. VL - 9 ER - TY - JOUR T1 - Transcription of cloned tRNA and 5S RNA genes in a Drosophila cell free extract. JF - Nucleic Acids Res Y1 - 1981 A1 - Dingermann, T A1 - Sharp, S A1 - Appel, B A1 - DeFranco, D A1 - Mount, S A1 - Heiermann, R A1 - Pongs, O A1 - Söll, D KW - Animals KW - Cell-Free System KW - Cloning, Molecular KW - Drosophila KW - In Vitro Techniques KW - RNA KW - RNA Polymerase III KW - RNA, Transfer KW - Transcription, Genetic KW - Xenopus laevis AB -

We describe the preparation of a cell-free extract from Drosophila Kc cells which allows transcription of a variety of cloned eukaryotic RNA polymerase III genes. The extract has low RNA-processing nuclease activity and thus the major products obtained are primary transcripts.

VL - 9 CP - 16 ER -