@article {49600, title = {Diarrhea in young children from low-income countries leads to large-scale alterations in intestinal microbiota composition.}, volume = {15}, year = {2014}, month = {2014}, pages = {R76}, abstract = {

BACKGROUND: Diarrheal diseases continue to contribute significantly to morbidity and mortality in infants and young children in developing countries. There is an urgent need to better understand the contributions of novel, potentially uncultured, diarrheal pathogens to severe diarrheal disease, as well as distortions in normal gut microbiota composition that might facilitate severe disease.

RESULTS: We use high throughput 16S rRNA gene sequencing to compare fecal microbiota composition in children under five years of age who have been diagnosed with moderate to severe diarrhea (MSD) with the microbiota from diarrhea-free controls. Our study includes 992 children from four low-income countries in West and East Africa, and Southeast Asia. Known pathogens, as well as bacteria currently not considered as important diarrhea-causing pathogens, are positively associated with MSD, and these include Escherichia/Shigella, and Granulicatella species, and Streptococcus mitis/pneumoniae groups. In both cases and controls, there tend to be distinct negative correlations between facultative anaerobic lineages and obligate anaerobic lineages. Overall genus-level microbiota composition exhibit a shift in controls from low to high levels of Prevotella and in MSD cases from high to low levels of Escherichia/Shigella in younger versus older children; however, there was significant variation among many genera by both site and age.

CONCLUSIONS: Our findings expand the current understanding of microbiota-associated diarrhea pathogenicity in young children from developing countries. Our findings are necessarily based on correlative analyses and must be further validated through epidemiological and molecular techniques.

}, keywords = {Bangladesh, Base Sequence, Case-Control Studies, Child, Preschool, Diarrhea, Infantile, Dysentery, Feces, Female, Gambia, HUMANS, Infant, Infant, Newborn, Intestines, Kenya, Male, Mali, Microbiota, Molecular Typing, Poverty, RNA, Bacterial, RNA, Ribosomal, 16S}, issn = {1474-760X}, doi = {10.1186/gb-2014-15-6-r76}, author = {Pop, Mihai and Walker, Alan W and Paulson, Joseph and Lindsay, Brianna and Antonio, Martin and Hossain, M Anowar and Oundo, Joseph and Tamboura, Boubou and Mai, Volker and Astrovskaya, Irina and Corrada Bravo, Hector and Rance, Richard and Stares, Mark and Levine, Myron M and Panchalingam, Sandra and Kotloff, Karen and Ikumapayi, Usman N and Ebruke, Chinelo and Adeyemi, Mitchell and Ahmed, Dilruba and Ahmed, Firoz and Alam, Meer Taifur and Amin, Ruhul and Siddiqui, Sabbir and Ochieng, John B and Ouma, Emmanuel and Juma, Jane and Mailu, Euince and Omore, Richard and Morris, J Glenn and Breiman, Robert F and Saha, Debasish and Parkhill, Julian and Nataro, James P and Stine, O Colin} } @article {49644, title = {Genomic organization and expression profile of the mucin-associated surface protein (masp) family of the human pathogen Trypanosoma cruzi.}, journal = {Nucleic Acids Res}, volume = {37}, year = {2009}, month = {2009 Jun}, pages = {3407-17}, abstract = {

A novel large multigene family was recently identified in the human pathogen Trypanosoma cruzi, causative agent of Chagas disease, and corresponds to approximately 6\% of the parasite diploid genome. The predicted gene products, mucin-associated surface proteins (MASPs), are characterized by highly conserved N- and C-terminal domains and a strikingly variable and repetitive central region. We report here an analysis of the genomic organization and expression profile of masp genes. Masps are not randomly distributed throughout the genome but instead are clustered with genes encoding mucin and other surface protein families. Masp transcripts vary in size, are preferentially expressed during the trypomastigote stage and contain highly conserved 5{\textquoteright} and 3{\textquoteright} untranslated regions. A sequence analysis of a trypomastigote cDNA library reveals the expression of multiple masp variants with a bias towards a particular masp subgroup. Immunofluorescence assays using antibodies generated against a MASP peptide reveals that the expression of particular MASPs at the cell membrane is limited to subsets of the parasite population. Western blots of phosphatidylinositol-specific phospholipase C (PI-PLC)-treated parasites suggest that MASP may be GPI-anchored and shed into the medium culture, thus contributing to the large repertoire of parasite polypeptides that are exposed to the host immune system.

}, keywords = {3{\textquoteright} Flanking Region, 5{\textquoteright} Flanking Region, Amino Acid Sequence, Animals, Base Sequence, Conserved Sequence, Gene Expression Profiling, Genes, Protozoan, Genome, Protozoan, Membrane Proteins, Molecular Sequence Data, Mucins, Multigene Family, Protozoan Proteins, RNA, Messenger, Trypanosoma cruzi}, issn = {1362-4962}, doi = {10.1093/nar/gkp172}, author = {Bartholomeu, Daniella C and Cerqueira, Gustavo C and Le{\~a}o, Ana Carolina A and daRocha, Wanderson D and Pais, Fabiano S and Macedo, Camila and Djikeng, Appolinaire and Teixeira, Santuza M R and El-Sayed, Najib M} } @article {49748, title = {A practical algorithm for finding maximal exact matches in large sequence datasets using sparse suffix arrays.}, journal = {Bioinformatics}, volume = {25}, year = {2009}, month = {2009 Jul 1}, pages = {1609-16}, abstract = {

MOTIVATION: High-throughput sequencing technologies place ever increasing demands on existing algorithms for sequence analysis. Algorithms for computing maximal exact matches (MEMs) between sequences appear in two contexts where high-throughput sequencing will vastly increase the volume of sequence data: (i) seeding alignments of high-throughput reads for genome assembly and (ii) designating anchor points for genome-genome comparisons.

RESULTS: We introduce a new algorithm for finding MEMs. The algorithm leverages a sparse suffix array (SA), a text index that stores every K-th position of the text. In contrast to a full text index that stores every position of the text, a sparse SA occupies much less memory. Even though we use a sparse index, the output of our algorithm is the same as a full text index algorithm as long as the space between the indexed suffixes is not greater than a minimum length of a MEM. By relying on partial matches and additional text scanning between indexed positions, the algorithm trades memory for extra computation. The reduced memory usage makes it possible to determine MEMs between significantly longer sequences.

AVAILABILITY: Source code for the algorithm is available under a BSD open source license at http://compbio.cs.princeton.edu/mems. The implementation can serve as a drop-in replacement for the MEMs algorithm in MUMmer 3.

}, keywords = {algorithms, Base Sequence, Genomics, sequence alignment, Sequence Analysis, DNA}, issn = {1367-4811}, doi = {10.1093/bioinformatics/btp275}, author = {Khan, Zia and Bloom, Joshua S and Kruglyak, Leonid and Singh, Mona} } @article {49642, title = {Members of a large retroposon family are determinants of post-transcriptional gene expression in Leishmania.}, journal = {PLoS Pathog}, volume = {3}, year = {2007}, month = {2007 Sep 7}, pages = {1291-307}, abstract = {

Trypanosomatids are unicellular protists that include the human pathogens Leishmania spp. (leishmaniasis), Trypanosoma brucei (sleeping sickness), and Trypanosoma cruzi (Chagas disease). Analysis of their recently completed genomes confirmed the presence of non-long-terminal repeat retrotransposons, also called retroposons. Using the 79-bp signature sequence common to all trypanosomatid retroposons as bait, we identified in the Leishmania major genome two new large families of small elements--LmSIDER1 (785 copies) and LmSIDER2 (1,073 copies)--that fulfill all the characteristics of extinct trypanosomatid retroposons. LmSIDERs are approximately 70 times more abundant in L. major compared to T. brucei and are found almost exclusively within the 3{\textquoteright}-untranslated regions (3{\textquoteright}UTRs) of L. major mRNAs. We provide experimental evidence that LmSIDER2 act as mRNA instability elements and that LmSIDER2-containing mRNAs are generally expressed at lower levels compared to the non-LmSIDER2 mRNAs. The considerable expansion of LmSIDERs within 3{\textquoteright}UTRs in an organism lacking transcriptional control and their role in regulating mRNA stability indicate that Leishmania have probably recycled these short retroposons to globally modulate the expression of a number of genes. To our knowledge, this is the first example in eukaryotes of the domestication and expansion of a family of mobile elements that have evolved to fulfill a critical cellular function.

}, keywords = {3{\textquoteright} Untranslated Regions, Animals, Base Sequence, Biological Evolution, Down-Regulation, Gene Expression Regulation, Genome, Protozoan, Leishmania, Leishmania major, Molecular Sequence Data, Retroelements, RNA, Messenger, sequence alignment, Trypanosoma brucei brucei, Trypanosoma cruzi}, issn = {1553-7374}, doi = {10.1371/journal.ppat.0030136}, author = {Bringaud, Frederic and M{\"u}ller, Michaela and Cerqueira, Gustavo Coutinho and Smith, Martin and Rochette, Annie and el-Sayed, Najib M A and Papadopoulou, Barbara and Ghedin, Elodie} } @article {49681, title = {Spliceosomal small nuclear RNA genes in 11 insect genomes.}, journal = {RNA}, volume = {13}, year = {2007}, month = {2007 Jan}, pages = {5-14}, abstract = {

The removal of introns from the primary transcripts of protein-coding genes is accomplished by the spliceosome, a large macromolecular complex of which small nuclear RNAs (snRNAs) are crucial components. Following the recent sequencing of the honeybee (Apis mellifera) genome, we used various computational methods, ranging from sequence similarity search to RNA secondary structure prediction, to search for putative snRNA genes (including their promoters) and to examine their pattern of conservation among 11 available insect genomes (A. mellifera, Tribolium castaneum, Bombyx mori, Anopheles gambiae, Aedes aegypti, and six Drosophila species). We identified candidates for all nine spliceosomal snRNA genes in all the analyzed genomes. All the species contain a similar number of snRNA genes, with the exception of A. aegypti, whose genome contains more U1, U2, and U5 genes, and A. mellifera, whose genome contains fewer U2 and U5 genes. We found that snRNA genes are generally more closely related to homologs within the same genus than to those in other genera. Promoter regions for all spliceosomal snRNA genes within each insect species share similar sequence motifs that are likely to correspond to the PSEA (proximal sequence element A), the binding site for snRNA activating protein complex, but these promoter elements vary in sequence among the five insect families surveyed here. In contrast to the other insect species investigated, Dipteran genomes are characterized by a rapid evolution (or loss) of components of the U12 spliceosome and a striking loss of U12-type introns.

}, keywords = {Animals, Base Sequence, Bees, Computational Biology, Diptera, Evolution, Molecular, Genes, Insect, Genome, Insect, Molecular Sequence Data, Nucleic Acid Conformation, Phylogeny, Promoter Regions, Genetic, RNA Splicing, RNA, Small Nuclear, Sequence Analysis, RNA, Spliceosomes}, issn = {1355-8382}, doi = {10.1261/rna.259207}, author = {Mount, Stephen M and Gotea, Valer and Lin, Chiao-Feng and Hernandez, Kristina and Makalowski, Wojciech} } @article {49679, title = {SplicePort--an interactive splice-site analysis tool.}, journal = {Nucleic Acids Res}, volume = {35}, year = {2007}, month = {2007 Jul}, pages = {W285-91}, abstract = {

SplicePort is a web-based tool for splice-site analysis that allows the user to make splice-site predictions for submitted sequences. In addition, the user can also browse the rich catalog of features that underlies these predictions, and which we have found capable of providing high classification accuracy on human splice sites. Feature selection is optimized for human splice sites, but the selected features are likely to be predictive for other mammals as well. With our interactive feature browsing and visualization tool, the user can view and explore subsets of features used in splice-site prediction (either the features that account for the classification of a specific input sequence or the complete collection of features). Selected feature sets can be searched, ranked or displayed easily. The user can group features into clusters and frequency plot WebLogos can be generated for each cluster. The user can browse the identified clusters and their contributing elements, looking for new interesting signals, or can validate previously observed signals. The SplicePort web server can be accessed at http://www.cs.umd.edu/projects/SplicePort and http://www.spliceport.org.

}, keywords = {Base Sequence, Chromosome mapping, Computational Biology, Computer simulation, DNA, Genome, HUMANS, Internet, Models, Genetic, Molecular Sequence Data, Pattern Recognition, Automated, RNA Splice Sites, sequence alignment, Sequence Analysis, DNA, User-Computer Interface}, issn = {1362-4962}, doi = {10.1093/nar/gkm407}, author = {Dogan, Rezarta Islamaj and Getoor, Lise and Wilbur, W John and Mount, Stephen M} } @article {49641, title = {Analysis of fat body transcriptome from the adult tsetse fly, Glossina morsitans morsitans.}, journal = {Insect Mol Biol}, volume = {15}, year = {2006}, month = {2006 Aug}, pages = {411-24}, abstract = {

Tsetse flies (Diptera: Glossinidia) are vectors of pathogenic African trypanosomes. To develop a foundation for tsetse physiology, a normalized expressed sequence tag (EST) library was constructed from fat body tissue of immune-stimulated Glossina morsitans morsitans. Analysis of 20,257 high-quality ESTs yielded 6372 unique genes comprised of 3059 tentative consensus (TC) sequences and 3313 singletons (available at http://aksoylab.yale.edu). We analysed the putative fat body transcriptome based on homology to other gene products with known functions available in the public domain. In particular, we describe the immune-related products, reproductive function related yolk proteins and milk-gland protein, iron metabolism regulating ferritins and transferrin, and tsetse{\textquoteright}s major energy source proline biosynthesis. Expression analysis of the three yolk proteins indicates that all are detected in females, while only the yolk protein with similarity to lipases, is expressed in males. Milk gland protein, apparently important for larval nutrition, however, is primarily synthesized by accessory milk gland tissue.

}, keywords = {Adipose Tissue, Animals, Base Sequence, Computational Biology, DNA Primers, Egg Proteins, Expressed Sequence Tags, Female, Gene Expression Profiling, Insect Vectors, Male, Molecular Sequence Data, Reverse Transcriptase Polymerase Chain Reaction, Sequence Analysis, DNA, Sex Factors, Tsetse Flies}, issn = {0962-1075}, doi = {10.1111/j.1365-2583.2006.00649.x}, author = {Attardo, G M and Strickler-Dinglasan, P and Perkin, S A H and Caler, E and Bonaldo, M F and Soares, M B and El-Sayeed, N and Aksoy, S} } @article {38287, title = {Genome analysis of multiple pathogenic isolates of Streptococcus agalactiae: implications for the microbial "pan-genome"}, journal = {Proceedings of the National Academy of Sciences of the United States of AmericaProceedings of the National Academy of Sciences of the United States of America}, volume = {102}, year = {2005}, note = {http://www.ncbi.nlm.nih.gov/pubmed/16172379?dopt=Abstract}, type = {10.1073/pnas.0506758102}, abstract = {The development of efficient and inexpensive genome sequencing methods has revolutionized the study of human bacterial pathogens and improved vaccine design. Unfortunately, the sequence of a single genome does not reflect how genetic variability drives pathogenesis within a bacterial species and also limits genome-wide screens for vaccine candidates or for antimicrobial targets. We have generated the genomic sequence of six strains representing the five major disease-causing serotypes of Streptococcus agalactiae, the main cause of neonatal infection in humans. Analysis of these genomes and those available in databases showed that the S. agalactiae species can be described by a pan-genome consisting of a core genome shared by all isolates, accounting for approximately 80\% of any single genome, plus a dispensable genome consisting of partially shared and strain-specific genes. Mathematical extrapolation of the data suggests that the gene reservoir available for inclusion in the S. agalactiae pan-genome is vast and that unique genes will continue to be identified even after sequencing hundreds of genomes.}, keywords = {Amino Acid Sequence, Bacterial Capsules, Base Sequence, Gene expression, Genes, Bacterial, Genetic Variation, Genome, Bacterial, Molecular Sequence Data, Phylogeny, sequence alignment, Sequence Analysis, DNA, Streptococcus agalactiae, virulence}, author = {Tettelin, Herv{\'e} and Masignani, Vega and Cieslewicz, Michael J. and Donati, Claudio and Medini, Duccio and Ward, Naomi L. and Angiuoli, Samuel V. and Crabtree, Jonathan and Jones, Amanda L. and Durkin, A. Scott and DeBoy, Robert T. and Davidsen, Tanja M. and Mora, Marirosa and Scarselli, Maria and Margarit y Ros, Immaculada and Peterson, Jeremy D. and Hauser, Christopher R. and Sundaram, Jaideep P. and Nelson, William C. and Madupu, Ramana and Brinkac, Lauren M. and Dodson, Robert J. and Rosovitz, Mary J. and Sullivan, Steven A. and Daugherty, Sean C. and Haft, Daniel H. and J. Selengut and Gwinn, Michelle L. and Zhou, Liwei and Zafar, Nikhat and Khouri, Hoda and Radune, Diana and Dimitrov, George and Watkins, Kisha and O{\textquoteright}Connor, Kevin J. B. and Smith, Shannon and Utterback, Teresa R. and White, Owen and Rubens, Craig E. and Grandi, Guido and Madoff, Lawrence C. and Kasper, Dennis L. and Telford, John L. and Wessels, Michael R. and Rappuoli, Rino and Fraser, Claire M.} } @article {49636, title = {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.}, journal = {Gene}, volume = {346}, year = {2005}, month = {2005 Feb 14}, pages = {153-61}, abstract = {

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.

}, keywords = {Amino Acid Sequence, Animals, Base Sequence, Chromosomes, Chromosomes, Artificial, Bacterial, DNA, Protozoan, Genes, Protozoan, Glycoproteins, Molecular Sequence Data, Multigene Family, Neuraminidase, Pseudogenes, Retroelements, Sequence Homology, Amino Acid, Sequence Homology, Nucleic Acid, Telomere, Trypanosoma cruzi}, issn = {0378-1119}, doi = {10.1016/j.gene.2004.10.014}, author = {Kim, Dong and Chiurillo, Miguel Angel and El-Sayed, Najib and Jones, Kristin and Santos, M{\'a}rcia R M and Porcile, Patricio E and Andersson, Bj{\"o}rn and Myler, Peter and da Silveira, Jose Franco and Ram{\'\i}rez, Jos{\'e} Luis} } @article {38165, title = {Comparison of the genome of the oral pathogen Treponema denticola with other spirochete genomes}, journal = {Proceedings of the National Academy of Sciences of the United States of AmericaProceedings of the National Academy of Sciences of the United States of America}, volume = {101}, year = {2004}, note = {http://www.ncbi.nlm.nih.gov/pubmed/15064399?dopt=Abstract}, type = {10.1073/pnas.0307639101}, abstract = {We present the complete 2,843,201-bp genome sequence of Treponema denticola (ATCC 35405) an oral spirochete associated with periodontal disease. Analysis of the T. denticola genome reveals factors mediating coaggregation, cell signaling, stress protection, and other competitive and cooperative measures, consistent with its pathogenic nature and lifestyle within the mixed-species environment of subgingival dental plaque. Comparisons with previously sequenced spirochete genomes revealed specific factors contributing to differences and similarities in spirochete physiology as well as pathogenic potential. The T. denticola genome is considerably larger in size than the genome of the related syphilis-causing spirochete Treponema pallidum. The differences in gene content appear to be attributable to a combination of three phenomena: genome reduction, lineage-specific expansions, and horizontal gene transfer. Genes lost due to reductive evolution appear to be largely involved in metabolism and transport, whereas some of the genes that have arisen due to lineage-specific expansions are implicated in various pathogenic interactions, and genes acquired via horizontal gene transfer are largely phage-related or of unknown function.}, keywords = {ATP-Binding Cassette Transporters, Bacterial Proteins, Base Sequence, Borrelia burgdorferi, Genes, Bacterial, Genome, Bacterial, Leptospira interrogans, Models, Genetic, Molecular Sequence Data, Mouth, Sequence Homology, Amino Acid, Treponema, Treponema pallidum}, author = {Seshadri, Rekha and Myers, Garry S. A. and Tettelin, Herv{\'e} and Eisen, Jonathan A. and Heidelberg, John F. and Dodson, Robert J. and Davidsen, Tanja M. and DeBoy, Robert T. and Fouts, Derrick E. and Haft, Dan H. and J. Selengut and Ren, Qinghu and Brinkac, Lauren M. and Madupu, Ramana and Kolonay, Jamie and Durkin, A. Scott and Daugherty, Sean C. and Shetty, Jyoti and Shvartsbeyn, Alla and Gebregeorgis, Elizabeth and Geer, Keita and Tsegaye, Getahun and Malek, Joel and Ayodeji, Bola and Shatsman, Sofiya and McLeod, Michael P. and Smajs, David and Howell, Jerrilyn K. and Pal, Sangita and Amin, Anita and Vashisth, Pankaj and McNeill, Thomas Z. and Xiang, Qin and Sodergren, Erica and Baca, Ernesto and Weinstock, George M. and Norris, Steven J. and Fraser, Claire M. and Paulsen, Ian T.} } @article {49634, title = {The ingi and RIME non-LTR retrotransposons are not randomly distributed in the genome of Trypanosoma brucei.}, journal = {Mol Biol Evol}, volume = {21}, year = {2004}, month = {2004 Mar}, pages = {520-8}, abstract = {

The ingi (long and autonomous) and RIME (short and nonautonomous) non--long-terminal repeat retrotransposons are the most abundant mobile elements characterized to date in the genome of the African trypanosome Trypanosoma brucei. These retrotransposons were thought to be randomly distributed, but a detailed and comprehensive analysis of their genomic distribution had not been performed until now. To address this question, we analyzed the ingi/RIME sequences and flanking sequences from the ongoing T. brucei genome sequencing project (TREU927/4 strain). Among the 81 ingi/RIME elements analyzed, 60\% are complete, and 7\% of the ingi elements (approximately 15 copies per haploid genome) appear to encode for their own transposition. The size of the direct repeat flanking the ingi/RIME retrotransposons is conserved (i.e., 12-bp), and a strong 11-bp consensus pattern precedes the 5{\textquoteright}-direct repeat. The presence of a consensus pattern upstream of the retroelements was confirmed by the analysis of the base occurrence in 294 GSS containing 5{\textquoteright}-adjacent ingi/RIME sequences. The conserved sequence is present upstream of ingis and RIMEs, suggesting that ingi-encoded enzymatic activities are used for retrotransposition of RIMEs, which are short nonautonomous retroelements. In conclusion, the ingi and RIME retroelements are not randomly distributed in the genome of T. brucei and are preceded by a conserved sequence, which may be the recognition site of the ingi-encoded endonuclease.

}, keywords = {Amino Acid Sequence, Animals, Base Sequence, Consensus Sequence, Genome, Protozoan, Molecular Sequence Data, Retroelements, Sequence Analysis, Trypanosoma brucei brucei}, issn = {0737-4038}, doi = {10.1093/molbev/msh045}, author = {Bringaud, Frederic and Biteau, Nicolas and Zuiderwijk, Eduard and Berriman, Matthew and El-Sayed, Najib M and Ghedin, Elodie and Melville, Sara E and Hall, Neil and Baltz, Th{\'e}o} } @article {38514, title = {Structural flexibility in the Burkholderia mallei genome}, journal = {Proceedings of the National Academy of Sciences of the United States of AmericaProceedings of the National Academy of Sciences of the United States of America}, volume = {101}, year = {2004}, note = {http://www.ncbi.nlm.nih.gov/pubmed/15377793?dopt=Abstract}, type = {10.1073/pnas.0403306101}, abstract = {The complete genome sequence of Burkholderia mallei ATCC 23344 provides insight into this highly infectious bacterium{\textquoteright}s pathogenicity and evolutionary history. B. mallei, the etiologic agent of glanders, has come under renewed scientific investigation as a result of recent concerns about its past and potential future use as a biological weapon. Genome analysis identified a number of putative virulence factors whose function was supported by comparative genome hybridization and expression profiling of the bacterium in hamster liver in vivo. The genome contains numerous insertion sequence elements that have mediated extensive deletions and rearrangements of the genome relative to Burkholderia pseudomallei. The genome also contains a vast number (>12,000) of simple sequence repeats. Variation in simple sequence repeats in key genes can provide a mechanism for generating antigenic variation that may account for the mammalian host{\textquoteright}s inability to mount a durable adaptive immune response to a B. mallei infection.}, keywords = {Animals, Base Composition, Base Sequence, Burkholderia mallei, Chromosomes, Bacterial, Cricetinae, Genome, Bacterial, Glanders, Liver, Mesocricetus, Molecular Sequence Data, Multigene Family, Oligonucleotide Array Sequence Analysis, Open Reading Frames, virulence}, author = {Nierman, William C. and DeShazer, David and Kim, H. Stanley and Tettelin, Herv{\'e} and Nelson, Karen E. and Feldblyum, Tamara and Ulrich, Ricky L. and Ronning, Catherine M. and Brinkac, Lauren M. and Daugherty, Sean C. and Davidsen, Tanja D. and DeBoy, Robert T. and Dimitrov, George and Dodson, Robert J. and Durkin, A. Scott and Gwinn, Michelle L. and Haft, Daniel H. and Khouri, Hoda and Kolonay, James F. and Madupu, Ramana and Mohammoud, Yasmin and Nelson, William C. and Radune, Diana and Romero, Claudia M. and Sarria, Saul and J. Selengut and Shamblin, Christine and Sullivan, Steven A. and White, Owen and Yu, Yan and Zafar, Nikhat and Zhou, Liwei and Fraser, Claire M.} } @article {38168, title = {The complete genome sequence of the Arabidopsis and tomato pathogen Pseudomonas syringae pv. tomato DC3000}, journal = {Proceedings of the National Academy of Sciences of the United States of AmericaProceedings of the National Academy of Sciences of the United States of America}, volume = {100}, year = {2003}, note = {http://www.ncbi.nlm.nih.gov/pubmed/12928499?dopt=Abstract}, type = {10.1073/pnas.1731982100}, abstract = {We report the complete genome sequence of the model bacterial pathogen Pseudomonas syringae pathovar tomato DC3000 (DC3000), which is pathogenic on tomato and Arabidopsis thaliana. The DC3000 genome (6.5 megabases) contains a circular chromosome and two plasmids, which collectively encode 5,763 ORFs. We identified 298 established and putative virulence genes, including several clusters of genes encoding 31 confirmed and 19 predicted type III secretion system effector proteins. Many of the virulence genes were members of paralogous families and also were proximal to mobile elements, which collectively comprise 7\% of the DC3000 genome. The bacterium possesses a large repertoire of transporters for the acquisition of nutrients, particularly sugars, as well as genes implicated in attachment to plant surfaces. Over 12\% of the genes are dedicated to regulation, which may reflect the need for rapid adaptation to the diverse environments encountered during epiphytic growth and pathogenesis. Comparative analyses confirmed a high degree of similarity with two sequenced pseudomonads, Pseudomonas putida and Pseudomonas aeruginosa, yet revealed 1,159 genes unique to DC3000, of which 811 lack a known function.}, keywords = {Arabidopsis, Base Sequence, Biological Transport, Genome, Bacterial, Lycopersicon esculentum, Molecular Sequence Data, Plant Growth Regulators, Plasmids, Pseudomonas, Reactive Oxygen Species, Siderophores, virulence}, author = {Buell, C. Robin and Joardar, Vinita and Lindeberg, Magdalen and J. Selengut and Paulsen, Ian T. and Gwinn, Michelle L. and Dodson, Robert J. and DeBoy, Robert T. and Durkin, A. Scott and Kolonay, James F. and Madupu, Ramana and Daugherty, Sean and Brinkac, Lauren and Beanan, Maureen J. and Haft, Daniel H. and Nelson, William C. and Davidsen, Tanja and Zafar, Nikhat and Zhou, Liwei and Liu, Jia and Yuan, Qiaoping and Khouri, Hoda and Fedorova, Nadia and Tran, Bao and Russell, Daniel and Berry, Kristi and Utterback, Teresa and Aken, Susan E. van and Feldblyum, Tamara V. and D{\textquoteright}Ascenzo, Mark and Deng, Wen-Ling and Ramos, Adela R. and Alfano, James R. and Cartinhour, Samuel and Chatterjee, Arun K. and Delaney, Terrence P. and Lazarowitz, Sondra G. and Martin, Gregory B. and Schneider, David J. and Tang, Xiaoyan and Bender, Carol L. and White, Owen and Fraser, Claire M. and Collmer, Alan} } @article {49687, title = {The draft genome of Ciona intestinalis: insights into chordate and vertebrate origins.}, journal = {Science}, volume = {298}, year = {2002}, month = {2002 Dec 13}, pages = {2157-67}, abstract = {

The first chordates appear in the fossil record at the time of the Cambrian explosion, nearly 550 million years ago. The modern ascidian tadpole represents a plausible approximation to these ancestral chordates. To illuminate the origins of chordate and vertebrates, we generated a draft of the protein-coding portion of the genome of the most studied ascidian, Ciona intestinalis. The Ciona genome contains approximately 16,000 protein-coding genes, similar to the number in other invertebrates, but only half that found in vertebrates. Vertebrate gene families are typically found in simplified form in Ciona, suggesting that ascidians contain the basic ancestral complement of genes involved in cell signaling and development. The ascidian genome has also acquired a number of lineage-specific innovations, including a group of genes engaged in cellulose metabolism that are related to those in bacteria and fungi.

}, keywords = {Alleles, Animals, Apoptosis, Base Sequence, Cellulose, Central Nervous System, Ciona intestinalis, Computational Biology, Endocrine System, Gene Dosage, Gene Duplication, genes, Genes, Homeobox, Genome, Heart, Immunity, Molecular Sequence Data, Multigene Family, Muscle Proteins, Organizers, Embryonic, Phylogeny, Polymorphism, Genetic, Proteins, Sequence Analysis, DNA, Sequence Homology, Nucleic Acid, Species Specificity, Thyroid Gland, Urochordata, Vertebrates}, issn = {1095-9203}, doi = {10.1126/science.1080049}, author = {Dehal, Paramvir and Satou, Yutaka and Campbell, Robert K and Chapman, Jarrod and Degnan, Bernard and De Tomaso, Anthony and Davidson, Brad and Di Gregorio, Anna and Gelpke, Maarten and Goodstein, David M and Harafuji, Naoe and Hastings, Kenneth E M and Ho, Isaac and Hotta, Kohji and Huang, Wayne and Kawashima, Takeshi and Lemaire, Patrick and Martinez, Diego and Meinertzhagen, Ian A and Necula, Simona and Nonaka, Masaru and Putnam, Nik and Rash, Sam and Saiga, Hidetoshi and Satake, Masanobu and Terry, Astrid and Yamada, Lixy and Wang, Hong-Gang and Awazu, Satoko and Azumi, Kaoru and Boore, Jeffrey and Branno, Margherita and Chin-Bow, Stephen and DeSantis, Rosaria and Doyle, Sharon and Francino, Pilar and Keys, David N and Haga, Shinobu and Hayashi, Hiroko and Hino, Kyosuke and Imai, Kaoru S and Inaba, Kazuo and Kano, Shungo and Kobayashi, Kenji and Kobayashi, Mari and Lee, Byung-In and Makabe, Kazuhiro W and Manohar, Chitra and Matassi, Giorgio and Medina, Monica and Mochizuki, Yasuaki and Mount, Steve and Morishita, Tomomi and Miura, Sachiko and Nakayama, Akie and Nishizaka, Satoko and Nomoto, Hisayo and Ohta, Fumiko and Oishi, Kazuko and Rigoutsos, Isidore and Sano, Masako and Sasaki, Akane and Sasakura, Yasunori and Shoguchi, Eiichi and Shin-i, Tadasu and Spagnuolo, Antoinetta and Stainier, Didier and Suzuki, Miho M and Tassy, Olivier and Takatori, Naohito and Tokuoka, Miki and Yagi, Kasumi and Yoshizaki, Fumiko and Wada, Shuichi and Zhang, Cindy and Hyatt, P Douglas and Larimer, Frank and Detter, Chris and Doggett, Norman and Glavina, Tijana and Hawkins, Trevor and Richardson, Paul and Lucas, Susan and Kohara, Yuji and Levine, Michael and Satoh, Nori and Rokhsar, Daniel S} } @article {49630, title = {Identification of non-autonomous non-LTR retrotransposons in the genome of Trypanosoma cruzi.}, journal = {Mol Biochem Parasitol}, volume = {124}, year = {2002}, month = {2002 Sep-Oct}, pages = {73-8}, abstract = {

As observed for most eukaryotic cells, trypanosomatids contains non-LTR retrotransposons randomly inserted in the nuclear genome. Autonomous retroelements which, code for their own transposition, have been characterized in Trypanosoma brucei (ingi) and Trypanosoma cruzi (L1Tc), whereas non-autonomous retroelements have only been characterized in T. brucei (RIME). Here, we have characterized in the genome of Trypanosoma cruzi four complete copies of a non-autonomous non-LTR retrotransposon, called NARTc. This 0.26 kb NARTc element has the characteristics of non-LTR retrotransposons: the presence a poly(dA) tail and of a short flanking duplicated motif. Analysis of the Genome Survey Sequence databases indicated that the Trypanosoma cruzi haploid genome contains about 140 NARTc copies and about twice as many L1Tc copies. Interestingly, the NARTc and L1Tc retroelements share, with the Trypanosoma brucei ingi and RIME retrotransposons, a common sequence (the first 45 bp with 91\% identity), whereas the remaining sequences are very divergent. This suggests that these four trypanosome non-LTR retrotransposons were derived from the same common ancester and the sequence of their 5{\textquoteright}-extremity may have a functional role. In addition, the genome of Leishmania major contains the same conserved motif present in the trypanosome retroelements, whicle no transposable elements have been detected so far in Leishmania sp.

}, keywords = {Animals, Base Sequence, Computational Biology, Genome, Protozoan, Long Interspersed Nucleotide Elements, Molecular Sequence Data, Retroelements, Short Interspersed Nucleotide Elements, Trypanosoma cruzi}, issn = {0166-6851}, author = {Bringaud, Frederic and Garc{\'\i}a-P{\'e}rez, Jos{\'e} Luis and Heras, Sara R and Ghedin, Elodie and El-Sayed, Najib M and Andersson, Bj{\"o}rn and Baltz, Th{\'e}o and Lopez, Manuel C} } @article {49631, title = {A new, expressed multigene family containing a hot spot for insertion of retroelements is associated with polymorphic subtelomeric regions of Trypanosoma brucei.}, journal = {Eukaryot Cell}, volume = {1}, year = {2002}, month = {2002 Feb}, pages = {137-51}, abstract = {

We describe a novel gene family that forms clusters in subtelomeric regions of Trypanosoma brucei chromosomes and partially accounts for the observed clustering of retrotransposons. The ingi and ribosomal inserted mobile element (RIME) non-LTR retrotransposons share 250 bp at both extremities and are the most abundant putatively mobile elements, with about 500 copies per haploid genome. From cDNA clones and subsequently in the T. brucei genomic DNA databases, we identified 52 homologous gene and pseudogene sequences, 16 of which contain a RIME and/or ingi retrotransposon inserted at exactly the same relative position. Here these genes are called the RHS family, for retrotransposon hot spot. Comparison of the protein sequences encoded by RHS genes (21 copies) and pseudogenes (24 copies) revealed a conserved central region containing an ATP/GTP-binding motif and the RIME/ingi insertion site. The RHS proteins share between 13 and 96\% identity, and six subfamilies, RHS1 to RHS6, can be defined on the basis of their divergent C-terminal domains. Immunofluorescence and Western blot analyses using RHS subfamily-specific immune sera show that RHS proteins are constitutively expressed and occur mainly in the nucleus. Analysis of Genome Survey Sequence databases indicated that the Trypanosoma brucei diploid genome contains about 280 RHS (pseudo)genes. Among the 52 identified RHS (pseudo)genes, 48 copies are in three RHS clusters located in subtelomeric regions of chromosomes Ia and II and adjacent to the active bloodstream form expression site in T. brucei strain TREU927/4 GUTat10.1. RHS genes comprise the remaining sequence of the size-polymorphic "repetitive region" described for T. brucei chromosome I, and a homologous gene family is present in the Trypanosoma cruzi genome.

}, keywords = {Amino Acid Sequence, Animals, Base Sequence, Cloning, Molecular, DNA Primers, DNA, Protozoan, Escherichia coli, Genes, Protozoan, Molecular Sequence Data, Multigene Family, Mutagenesis, Insertional, Phylogeny, Polymorphism, Genetic, Protozoan Proteins, Pseudogenes, Retroelements, sequence alignment, Sequence Homology, Amino Acid, Telomere, Trypanosoma brucei brucei, Trypanosoma cruzi}, issn = {1535-9778}, author = {Bringaud, Frederic and Biteau, Nicolas and Melville, Sara E and Hez, St{\'e}phanie and El-Sayed, Najib M and Leech, Vanessa and Berriman, Matthew and Hall, Neil and Donelson, John E and Baltz, Th{\'e}o} } @article {49632, title = {Trypanosoma cruzi: RNA structure and post-transcriptional control of tubulin gene expression.}, journal = {Exp Parasitol}, volume = {102}, year = {2002}, month = {2002 Nov-Dec}, pages = {123-33}, abstract = {

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{\textquoteright} 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{\textquoteright} 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.

}, keywords = {Animals, Base Sequence, Blotting, Northern, DNA, Complementary, DNA, Protozoan, Gene Expression Regulation, Half-Life, Life Cycle Stages, Molecular Sequence Data, RNA Processing, Post-Transcriptional, RNA, Messenger, RNA, Protozoan, Transcription, Genetic, Transfection, Trypanosoma cruzi, Tubulin}, issn = {0014-4894}, author = {Bartholomeu, Daniella C and Silva, Rosiane A and Galv{\~a}o, Lucia M C and el-Sayed, Najib M A and Donelson, John E and Teixeira, Santuza M R} } @article {49695, title = {AT-AC introns: an ATtACk on dogma.}, journal = {Science}, volume = {271}, year = {1996}, month = {1996 Mar 22}, pages = {1690-2}, keywords = {Animals, Base Composition, Base Sequence, Consensus Sequence, HUMANS, Introns, Molecular Sequence Data, Mutation, RNA Precursors, RNA Splicing, RNA, Small Nuclear, Spliceosomes}, issn = {0036-8075}, author = {Mount, S M} } @article {49696, title = {Genetic enhancement of RNA-processing defects by a dominant mutation in B52, the Drosophila gene for an SR protein splicing factor.}, journal = {Mol Cell Biol}, volume = {15}, year = {1995}, month = {1995 Nov}, pages = {6273-82}, abstract = {

SR proteins are essential for pre-mRNA splicing in vitro, act early in the splicing pathway, and can influence alternative splice site choice. Here we describe the isolation of both dominant and loss-of-function alleles of B52, the gene for a Drosophila SR protein. The allele B52ED was identified as a dominant second-site enhancer of white-apricot (wa), a retrotransposon insertion in the second intron of the eye pigmentation gene white with a complex RNA-processing defect. B52ED also exaggerates the mutant phenotype of a distinct white allele carrying a 5{\textquoteright} splice site mutation (wDR18), and alters the pattern of sex-specific splicing at doublesex under sensitized conditions, so that the male-specific splice is favored. In addition to being a dominant enhancer of these RNA-processing defects, B52ED is a recessive lethal allele that fails to complement other lethal alleles of B52. Comparison of B52ED with the B52+ allele from which it was derived revealed a single change in a conserved amino acid in the beta 4 strand of the first RNA-binding domain of B52, which suggests that altered RNA binding is responsible for the dominant phenotype. Reversion of the B52ED dominant allele with X rays led to the isolation of a B52 null allele. Together, these results indicate a critical role for the SR protein B52 in pre-mRNA splicing in vivo.

}, keywords = {Alleles, Amino Acid Sequence, Animals, Base Sequence, DNA Primers, Drosophila melanogaster, Drosophila Proteins, Frameshift Mutation, Genes, Dominant, Genes, Insect, Molecular Sequence Data, Nuclear Proteins, Phosphoproteins, Point Mutation, Protein Structure, Tertiary, Proteins, RNA Splicing, RNA-Binding Proteins, Sequence Deletion, Sex Determination Analysis}, issn = {0270-7306}, author = {Peng, X and Mount, S M} } @article {49697, title = {Localization of sequences required for size-specific splicing of a small Drosophila intron in vitro.}, journal = {J Mol Biol}, volume = {253}, year = {1995}, month = {1995 Oct 27}, pages = {426-37}, abstract = {

Many introns in Drosophila and other invertebrates are less than 80 nucleotides in length, too small to be recognized by the vertebrate splicing machinery. Comparison of nuclear splicing extracts from human HeLa and Drosophila Kc cells has revealed species-specificity, consistent with the observed size differences. Here we present additional results with the 68 nucleotide fifth intron of the Drosophila myosin heavy chain gene. As observed with the 74 nucleotide second intron of the Drosophila white gene, the wild-type myosin intron is accurately spliced in a homologous extract, and increasing the size by 16 nucleotides both eliminates splicing in the Drosophila extract and allows accurate splicing in the human extract. In contrast to previous results, however, an upstream cryptic 5{\textquoteright} splice site is activated when the wild-type myosin intron is tested in a human HeLa cell nuclear extract, resulting in the removal of a 98 nucleotide intron. The size dependence of splicing in Drosophila extracts is also intron-specific; we noted that a naturally larger (150 nucleotide) intron from the ftz gene is efficiently spliced in Kc cell extracts that do not splice enlarged introns (of 84, 90, 150 or 350 nucleotides) derived from the 74 nucleotide white intron. Here, we have exploited that observation, using a series of hybrid introns to show that a region of 46 nucleotides at the 3{\textquoteright} end of the white intron is sufficient to confer the species-specific size effect. At least two sequence elements within this region, yet distinct from previously described branchpoint and pyrimidine tract signals, are required for efficient splicing of small hybrid introns in vitro.

}, keywords = {Animals, Base Sequence, Cell Line, DNA, Drosophila, Genes, Insect, HeLa Cells, HUMANS, Introns, Molecular Sequence Data, Myosin Heavy Chains, RNA Splicing, Species Specificity}, issn = {0022-2836}, doi = {10.1006/jmbi.1995.0564}, author = {Guo, M and Mount, S M} } @article {49699, title = {P element-mediated in vivo deletion analysis of white-apricot: deletions between direct repeats are strongly favored.}, journal = {Genetics}, volume = {136}, year = {1994}, month = {1994 Mar}, pages = {1001-11}, abstract = {

We have isolated and characterized deletions arising within a P transposon, P[hswa], in the presence of P transposase. P[hswa] carries white-apricot (wa) sequences, including a complete copia element, under the control of an hsp70 promoter, and resembles the original wa allele in eye color phenotype. In the presence of P transposase, P[hswa] shows a high overall rate (approximately 3\%) of germline mutations that result in increased eye pigmentation. Of 234 derivatives of P[hswa] with greatly increased eye pigmentation, at least 205 carried deletions within copia. Of these, 201 were precise deletions between the directly repeated 276-nucleotide copia long terminal repeats (LTRs), and four were unique deletions. High rates of transposase-induced precise deletion were observed within another P transposon carrying unrelated 599 nucleotide repeats (yeast 2 mu FLP; recombinase target sites) separated by 5.7 kb. Our observation that P element-mediated deletion formation occurs preferentially between direct repeats suggests general methods for controlling deletion formation.

}, keywords = {Alleles, Animals, Animals, Genetically Modified, Base Sequence, Crosses, Genetic, DNA, DNA Transposable Elements, Drosophila, Eye Color, Female, Genes, Insect, Male, Molecular Sequence Data, Nucleotidyltransferases, PHENOTYPE, Recombination, Genetic, Repetitive Sequences, Nucleic Acid, Sequence Deletion, Transformation, Genetic, Transposases}, issn = {0016-6731}, author = {Kurkulos, M and Weinberg, J M and Roy, D and Mount, S M} } @article {49698, title = {Suppressor U1 snRNAs in Drosophila.}, journal = {Genetics}, volume = {138}, year = {1994}, month = {1994 Oct}, pages = {365-78}, abstract = {

Although the role of U1 small nuclear RNAs (snRNAs) in 5{\textquoteright} splice site recognition is well established, suppressor U1 snRNAs active in intact multicellular animals have been lacking. Here we describe suppression of a 5{\textquoteright} splice site mutation in the Drosophila melanogaster white gene (wDR18) by compensatory changes in U1 snRNA. Mutation of positions -1 and +6 of the 5{\textquoteright} splice site of the second intron (ACG[GTGAGT to ACC]GTGAGC) results in the accumulation of RNA retaining this 74-nucleotide intron in both transfected cells and transgenic flies. U1-3G, a suppressor U1 snRNA which restores base-pairing at position +6 of the mutant intron, increases the ratio of spliced to unspliced wDR18 RNA up to fivefold in transfected Schneider cells and increases eye pigmentation in wDR18 flies. U1-9G, which targets position -1, suppresses wDR18 in transfected cells less well. U1-3G,9G has the same effect as U1-3G although it accumulates to lower levels. Suppression of wDR18 has revealed that the U1b embryonic variant (G134 to U) is active in Schneider cells and pupal eye discs. However, the combination of 9G with 134U leads to reduced accumulation of both U1b-9G and U1b-3G,9G, possibly because nucleotides 9 and 134 both participate in a potential long-range intramolecular base-pairing interaction. High levels of functional U1-3G suppressor reduce both viability and fertility in transformed flies. These results show that, despite the difficulties inherent in stably altering splice site selection in multicellular organisms, it is possible to obtain suppressor U1 snRNAs in flies.

}, keywords = {Alternative Splicing, Animals, Base Sequence, Cell Line, Cell Nucleus, DNA Primers, Drosophila melanogaster, Female, Genes, Suppressor, Genetic Variation, GENOTYPE, Introns, Male, Molecular Sequence Data, Mutagenesis, Site-Directed, Nucleic Acid Conformation, Oligodeoxyribonucleotides, PHENOTYPE, Recombinant Proteins, Ribonucleoprotein, U1 Small Nuclear, RNA, Small Nuclear, Transfection, Transformation, Genetic}, issn = {0016-6731}, author = {Lo, P C and Roy, D and Mount, S M} } @article {49701, title = {Species-specific signals for the splicing of a short Drosophila intron in vitro.}, journal = {Mol Cell Biol}, volume = {13}, year = {1993}, month = {1993 Feb}, pages = {1104-18}, abstract = {

The effects of branchpoint sequence, the pyrimidine stretch, and intron size on the splicing efficiency of the Drosophila white gene second intron were examined in nuclear extracts from Drosophila and human cells. This 74-nucleotide intron is typical of many Drosophila introns in that it lacks a significant pyrimidine stretch and is below the minimum size required for splicing in human nuclear extracts. Alteration of sequences of adjacent to the 3{\textquoteright} splice site to create a pyrimidine stretch was necessary for splicing in human, but not Drosophila, extracts. Increasing the size of this intron with insertions between the 5{\textquoteright} splice site and the branchpoint greatly reduced the efficiency of splicing of introns longer than 79 nucleotides in Drosophila extracts but had an opposite effect in human extracts, in which introns longer than 78 nucleotides were spliced with much greater efficiency. The white-apricot copia insertion is immediately adjacent to the branchpoint normally used in the splicing of this intron, and a copia long terminal repeat insertion prevents splicing in Drosophila, but not human, extracts. However, a consensus branchpoint does not restore the splicing of introns containing the copia long terminal repeat, and alteration of the wild-type branchpoint sequence alone does not eliminate splicing. These results demonstrate species specificity of splicing signals, particularly pyrimidine stretch and size requirements, and raise the possibility that variant mechanisms not found in mammals may operate in the splicing of small introns in Drosophila and possibly other species.

}, keywords = {Animals, Base Sequence, Cell Nucleus, Consensus Sequence, DNA, DNA Transposable Elements, Drosophila, Drosophila Proteins, Electrophoresis, Polyacrylamide Gel, HeLa Cells, HUMANS, Introns, Molecular Sequence Data, Mutation, Peptide Hydrolases, Proteins, Regulatory Sequences, Nucleic Acid, Retroelements, RNA Splicing, Species Specificity}, issn = {0270-7306}, author = {Guo, M and Lo, P C and Mount, S M} } @article {49702, title = {Splicing signals in Drosophila: intron size, information content, and consensus sequences.}, journal = {Nucleic Acids Res}, volume = {20}, year = {1992}, month = {1992 Aug 25}, pages = {4255-62}, abstract = {

A database of 209 Drosophila introns was extracted from Genbank (release number 64.0) and examined by a number of methods in order to characterize features that might serve as signals for messenger RNA splicing. A tight distribution of sizes was observed: while the smallest introns in the database are 51 nucleotides, more than half are less than 80 nucleotides in length, and most of these have lengths in the range of 59-67 nucleotides. Drosophila splice sites found in large and small introns differ in only minor ways from each other and from those found in vertebrate introns. However, larger introns have greater pyrimidine-richness in the region between 11 and 21 nucleotides upstream of 3{\textquoteright} splice sites. The Drosophila branchpoint consensus matrix resembles C T A A T (in which branch formation occurs at the underlined A), and differs from the corresponding mammalian signal in the absence of G at the position immediately preceding the branchpoint. The distribution of occurrences of this sequence suggests a minimum distance between 5{\textquoteright} splice sites and branchpoints of about 38 nucleotides, and a minimum distance between 3{\textquoteright} splice sites and branchpoints of 15 nucleotides. The methods we have used detect no information in exon sequences other than in the few nucleotides immediately adjacent to the splice sites. However, Drosophila resembles many other species in that there is a discontinuity in A + T content between exons and introns, which are A + T rich.

}, keywords = {Animals, Base Sequence, Consensus Sequence, Databases, Factual, Drosophila, Introns, Molecular Sequence Data, RNA Splicing, RNA, Messenger, software}, issn = {0305-1048}, author = {Mount, S M and Burks, C and Hertz, G and Stormo, G D and White, O and Fields, C} } @article {49703, title = {Polyadenylylation in copia requires unusually distant upstream sequences.}, journal = {Proc Natl Acad Sci U S A}, volume = {88}, year = {1991}, month = {1991 Apr 15}, pages = {3038-42}, abstract = {

Retroviruses and related genetic elements generate terminally redundant RNA products by differential polyadenylylation within a long terminal repeat. Expression of the white-apricot (wa) allele of Drosophila melanogaster, which carries an insertion of the 5.1-kilobase retrovirus-like transposable element copia in a small intron, is influenced by signals within copia. By using this indicator, we have isolated a 518-base-pair deletion, 312 base pairs upstream of the copia polyadenylylation site, that is phenotypically like much larger deletions and eliminates RNA species polyadenylylated in copia. This requirement of distant upstream sequences for copia polyadenylylation has implications for the expression of many genetic elements bearing long terminal repeats.

}, keywords = {Animals, Base Sequence, Blotting, Northern, DNA Transposable Elements, Drosophila melanogaster, Eye Color, Molecular Sequence Data, Oligonucleotides, Polymerase Chain Reaction, Regulatory Sequences, Nucleic Acid, Repetitive Sequences, Nucleic Acid, RNA Processing, Post-Transcriptional, RNA, Messenger}, issn = {0027-8424}, author = {Kurkulos, M and Weinberg, J M and Pepling, M E and Mount, S M} } @article {49704, title = {Drosophila melanogaster genes for U1 snRNA variants and their expression during development.}, journal = {Nucleic Acids Res}, volume = {18}, year = {1990}, month = {1990 Dec 11}, pages = {6971-9}, abstract = {

We have cloned and characterized a complete set of seven U1-related sequences from Drosophila melanogaster. These sequences are located at the three cytogenetic loci 21D, 82E, and 95C. Three of these sequences have been previously studied: one U1 gene at 21D which encodes the prototype U1 sequence (U1a), one U1 gene at 82E which encodes a U1 variant with a single nucleotide substitution (U1b), and a pseudogene at 82E. The four previously uncharacterized genes are another U1b gene at 82E, two additional U1a genes at 95C, and a U1 gene at 95C which encodes a new variant (U1c) with a distinct single nucleotide change relative to U1a. Three blocks of 5{\textquoteright} flanking sequence similarity are common to all six full length genes. Using specific primer extension assays, we have observed that the U1b RNA is expressed in Drosophila Kc cells and is associated with snRNP proteins, suggesting that the U1b-containing snRNP particles are able to participate in the process of pre-mRNA splicing. We have also examined the expression throughout Drosophila development of the two U1 variants relative to the prototype sequence. The U1c variant is undetectable by our methods, while the U1b variant exhibits a primarily embryonic pattern reminiscent of the expression of certain U1 variants in sea urchin, Xenopus, and mouse.

}, keywords = {Animals, Base Sequence, Blotting, Southern, Cloning, Molecular, Drosophila melanogaster, Gene Expression Regulation, genes, Genetic Variation, Molecular Sequence Data, Nucleic Acid Conformation, Pseudogenes, Restriction Mapping, RNA, Small Nuclear}, issn = {0305-1048}, author = {Lo, P C and Mount, S M} } @article {49707, title = {Sequence of a cDNA from the Drosophila melanogaster white gene.}, journal = {Nucleic Acids Res}, volume = {18}, year = {1990}, month = {1990 Mar 25}, pages = {1633}, keywords = {Amino Acid Sequence, Animals, Base Sequence, DNA, Drosophila melanogaster, Eye Color, genes, Molecular Sequence Data}, issn = {0305-1048}, author = {Pepling, M and Mount, S M} } @article {49706, title = {Structure and expression of the Drosophila melanogaster gene for the U1 small nuclear ribonucleoprotein particle 70K protein.}, journal = {Mol Cell Biol}, volume = {10}, year = {1990}, month = {1990 Jun}, pages = {2492-502}, abstract = {

A genomic clone encoding the Drosophila U1 small nuclear ribonucleoprotein particle 70K protein was isolated by hybridization with a human U1 small nuclear ribonucleoprotein particle 70K protein cDNA. Southern blot and in situ hybridizations showed that this U1 70K gene is unique in the Drosophila genome, residing at cytological position 27D1,2. Polyadenylated transcripts of 1.9 and 3.1 kilobases were observed. While the 1.9-kilobase mRNA is always more abundant, the ratio of these two transcripts is developmentally regulated. Analysis of cDNA and genomic sequences indicated that these two RNAs encode an identical protein with a predicted molecular weight of 52,879. Comparison of the U1 70K proteins predicted from Drosophila, human, and Xenopus cDNAs revealed 68\% amino acid identity in the most amino-terminal 214 amino acids, which include a sequence motif common to many proteins which bind RNA. The carboxy-terminal half is less well conserved but is highly charged and contains distinctive arginine-rich regions in all three species. These arginine-rich regions contain stretches of arginine-serine dipeptides like those found in transformer, transformer-2, and suppressor-of-white-apricot proteins, all of which have been identified as regulators of mRNA splicing in Drosophila melanogaster.

}, keywords = {Amino Acid Sequence, Animals, Base Sequence, Blotting, Northern, Blotting, Southern, Cloning, Molecular, DNA, Drosophila melanogaster, Gene expression, Gene Library, genes, HUMANS, Molecular Sequence Data, Molecular Weight, Oligonucleotide Probes, Poly A, Ribonucleoproteins, Ribonucleoproteins, Small Nuclear, RNA, RNA, Messenger, Sequence Homology, Nucleic Acid, Xenopus}, issn = {0270-7306}, author = {Mancebo, R and Lo, P C and Mount, S M} } @article {49708, title = {Partial revertants of the transposable element-associated suppressible allele white-apricot in Drosophila melanogaster: structures and responsiveness to genetic modifiers.}, journal = {Genetics}, volume = {118}, year = {1988}, month = {1988 Feb}, pages = {221-34}, abstract = {

The eye color phenotype of white-apricot (wa), a mutant allele of the white locus caused by the insertion of the transposable element copia into a small intron, is suppressed by the extragenic suppressor suppressor-of-white-apricot (su(wa] and enhanced by the extragenic enhancers suppressor-of-forked su(f] and Enhancer-of-white-apricot (E(wa]. Derivatives of wa have been analyzed molecularly and genetically in order to correlate the structure of these derivatives with their response to modifiers. Derivatives in which the copia element is replaced precisely by a solo long terminal repeat (sLTR) were generated in vitro and returned to the germline by P-element mediated transformation; flies carrying this allele within a P transposon show a nearly wild-type phenotype and no response to either su(f) or su(wa). In addition, eleven partial phenotypic revertants of wa were analyzed. Of these, one appears to be a duplication of a large region which includes wa, three are new alleles of su(wa), two are sLTR derivatives whose properties confirm results obtained using transformation, and five are secondary insertions into the copia element within wa. One of these, waR84h, differs from wa by the insertion of the most 3{\textquoteright} 83 nucleotides of the I factor. The five insertion derivatives show a variety of phenotypes and modes of interaction with su[f) and su(wa). The eye pigmentation of waR84h is affected by su(f) and E(wa), but not su(wa). These results demonstrate that copia (as opposed to the interruption of white sequences) is essential for the wa phenotype and its response to genetic modifiers, and that there are multiple mechanisms for the alteration of the wa phenotype by modifiers.

}, keywords = {Alleles, Animals, Base Sequence, DNA Transposable Elements, Drosophila melanogaster, Enhancer Elements, Genetic, GENOTYPE, Molecular Sequence Data, Mutation, Suppression, Genetic}, issn = {0016-6731}, author = {Mount, S M and Green, M M and Rubin, G M} } @article {49710, title = {Complete nucleotide sequence of the Drosophila transposable element copia: homology between copia and retroviral proteins.}, journal = {Mol Cell Biol}, volume = {5}, year = {1985}, month = {1985 Jul}, pages = {1630-8}, abstract = {

We have determined the complete nucleotide sequence of the copia element present at the white-apricot allele of the white locus in Drosophila melanogaster. This transposable element is 5,146 nucleotides long and contains a single long open reading frame of 4,227 nucleotides. Analysis of the coding potential of the large open reading frame, which appears to encode a polyprotein, revealed weak homology to a number of retroviral proteins, including a protease, nucleic acid-binding protein, and reverse transcriptase. Better homology existed between another part of the copia open reading frame and a region of the retroviral pol gene recently shown to be distinct from reverse transcriptase and required for the integration of circular DNA forms of the retroviral genome to form proviruses. Comparison of the copia sequence with those of the Saccharomyces cerevisiae transposable element Ty, several vertebrate retroviruses, and the D. melanogaster copia-like element 17.6 showed that Ty was most similar to copia, sharing amino acid sequence homology and organizational features not found in the other genetic elements.

}, keywords = {Amino Acid Sequence, Animals, Base Sequence, Codon, DNA Helicases, DNA Transposable Elements, Drosophila melanogaster, Gene Expression Regulation, Gene Products, gag, Integrases, Repetitive Sequences, Nucleic Acid, Retroviridae, RNA-Directed DNA Polymerase, Viral Envelope Proteins, Viral Proteins}, issn = {0270-7306}, author = {Mount, S M and Rubin, G M} } @article {49715, title = {Pseudogenes for human small nuclear RNA U3 appear to arise by integration of self-primed reverse transcripts of the RNA into new chromosomal sites.}, journal = {Cell}, volume = {32}, year = {1983}, month = {1983 Feb}, pages = {461-72}, abstract = {

We find that both human and rat U3 snRNA can function as self-priming templates for AMV reverse transcriptase in vitro. The 74 base cDNA is primed by the 3{\textquoteright} end of intact U3 snRNA, and spans the characteristically truncated 69 or 70 base U3 sequence found in four different human U3 pseudogenes. The ability of human and rat U3 snRNA to self-prime is consistent with a U3 secondary structure model derived by a comparison between rat U3 snRNA and the homologous D2 snRNA from Dictyostelium discoideum. We propose that U3 pseudogenes are generated in vivo by integration of a self-primed cDNA copy of U3 snRNA at new chromosomal sites. We also consider the possibility that the same cDNA mediates gene conversion at the 5{\textquoteright} end of bona fide U3 genes where, over the entire region spanned by the U3 cDNA, the two rat U3 sequence variants U3A and U3B are identical.

}, keywords = {Animals, Base Sequence, DNA, genes, HUMANS, Nucleic Acid Conformation, Rats, Recombination, Genetic, Repetitive Sequences, Nucleic Acid, RNA, RNA, Small Nuclear, RNA-Directed DNA Polymerase, Templates, Genetic, Transcription, Genetic}, issn = {0092-8674}, author = {Bernstein, L B and Mount, S M and Weiner, A M} } @article {49712, title = {RNA processing. Sequences that signal where to splice.}, journal = {Nature}, volume = {304}, year = {1983}, pages = {309-10}, keywords = {Base Sequence, RNA Splicing, Saccharomyces cerevisiae}, issn = {0028-0836}, author = {Mount, S M} } @article {49716, title = {Small ribonucleoproteins from eukaryotes: structures and roles in RNA biogenesis.}, journal = {Cold Spring Harb Symp Quant Biol}, volume = {47 Pt 2}, year = {1983}, month = {1983}, pages = {893-900}, keywords = {Animals, Base Sequence, HeLa Cells, HUMANS, Mice, Molecular Weight, Nucleic Acid Conformation, Nucleic Acid Hybridization, Nucleoproteins, Ribonucleoproteins, Ribonucleoproteins, Small Nuclear, RNA Polymerase III, Transcription, Genetic}, issn = {0091-7451}, author = {Steitz, J A and Wolin, S L and Rinke, J and Pettersson, I and Mount, S M and Lerner, E A and Hinterberger, M and Gottlieb, E} } @article {49711, title = {Splicing of messenger RNA precursors is inhibited by antisera to small nuclear ribonucleoprotein.}, journal = {Cell}, volume = {35}, year = {1983}, month = {1983 Nov}, pages = {101-7}, abstract = {

A mouse monoclonal antibody and human autoimmune sera directed against various classes of small ribonucleoprotein particles have been tested for inhibition of mRNA splicing in a soluble in vitro system. The splicing of the first and second leader exons of adenovirus late RNA was inhibited only by those sera that reacted with U1 RNP. Both U1 RNP-specific human autoimmune serum and sera directed against the Sm class of small nuclear RNPs, including a mouse monoclonal antibody, specifically inhibited splicing. Antisera specific for U2 RNP had no effect on splicing nor did antisera specific for the La or Ro class of small RNPs. These results suggest that U1 RNP is essential for the splicing of mRNA precursors.

}, keywords = {Adenoviruses, Human, Antigens, Autoantigens, Base Sequence, Cell Extracts, HeLa Cells, HUMANS, Immune Sera, Nucleic Acid Precursors, Ribonucleoproteins, Ribonucleoproteins, Small Nuclear, RNA, RNA Precursors, RNA Splicing, RNA, Messenger, RNA, Small Cytoplasmic, RNA, Viral, Transcription, Genetic}, issn = {0092-8674}, author = {Padgett, R A and Mount, S M and Steitz, J A and Sharp, P A} } @article {49714, title = {The U1 small nuclear RNA-protein complex selectively binds a 5{\textquoteright} splice site in vitro.}, journal = {Cell}, volume = {33}, year = {1983}, month = {1983 Jun}, pages = {509-18}, abstract = {

The ability of purified U1 small nuclear RNA-protein complexes (U1 snRNPs) to bind in vitro to two RNAs transcribed from recombinant DNA clones by bacteriophage T7 RNA polymerase has been studied. A transcript which contains sequences corresponding to the small intron and flanking exons of the major mouse beta-globin gene is bound in marked preference to an RNA devoid of splice site sequences. The site of U1 snRNP binding to the globin RNA has been defined by T1 ribonuclease digestion of the RNA-U1 snRNP complex. A 15-17-nucleotide region, including the 5{\textquoteright} splice site, remains undigested and complexed with the snRNP such that it can be co-precipitated by antibodies directed against the U1 snRNP. Partial proteinase K digestion of the U1 snRNP abolishes interaction with the globin RNA, indicating that the snRNP proteins contribute significantly to RNA binding. No RNA cleavage, splicing, or recognition of the 3{\textquoteright} splice site by U1 snRNPs has been detected. Our results are discussed in terms of the probable role of U1 snRNPs in the messenger RNA splicing of eucaryotic cell nuclei.

}, keywords = {Base Sequence, DNA-Directed RNA Polymerases, HUMANS, Nucleoproteins, Ribonuclease T1, Ribonucleoproteins, Ribonucleoproteins, Small Nuclear, RNA, RNA Splicing, T-Phages}, issn = {0092-8674}, author = {Mount, S M and Pettersson, I and Hinterberger, M and Karmas, A and Steitz, J A} } @article {49717, title = {A catalogue of splice junction sequences.}, journal = {Nucleic Acids Res}, volume = {10}, year = {1982}, month = {1982 Jan 22}, pages = {459-72}, abstract = {

Splice junction sequences from a large number of nuclear and viral genes encoding protein have been collected. The sequence CAAG/GTAGAGT was found to be a consensus of 139 exon-intron boundaries (or donor sequences) and (TC)nNCTAG/G was found to be a consensus of 130 intron-exon boundaries (or acceptor sequences). The possible role of splice junction sequences as signals for processing is discussed.

}, keywords = {Animals, Base Sequence, genes, Genes, Viral, HUMANS, Repetitive Sequences, Nucleic Acid, RNA Splicing, Species Specificity}, issn = {0305-1048}, author = {Mount, S M} } @article {49719, title = {Sequence of U1 RNA from Drosophila melanogaster: implications for U1 secondary structure and possible involvement in splicing.}, journal = {Nucleic Acids Res}, volume = {9}, year = {1981}, month = {1981 Dec 11}, pages = {6351-68}, abstract = {

U1 RNA from cultured Drosophila melanogaster cells (Kc) was identified by its ability to be recognized, as an RNP, by anti-(U1)RNP antibodies from human lupus patients. Its sequence was deduced largely from direct analysis of the RNA molecule and then confirmed by DNA sequence determinations on a genomic clone isolated by hybridization to Drosophila U1 RNA. The Drosophila U1 RNA sequence exhibits 72\% agreement with human U1 RNA. Nucleotides 3-11, which are complementary to the entire consensus sequence for donor (5{\textquoteright}) splice junctions in hnRNA, and to part of the acceptor (3{\textquoteright}) consensus, are exactly conserved. However, nucleotides 14-21, postulated to interact only with acceptor junctions, differ. Comparison of the Drosophila U1 sequence with vertebrate U1 sequences allows a particular secondary structure model to be preferred over others. These results are consistent with the hypothesis that U1 snRNPs are involved in splicing, but suggest specific modifications of the model detailing molecular interactions between U1 RNA and hnRNA during the splicing reaction.

}, keywords = {Animals, Antibodies, Autoimmune Diseases, Base Sequence, Cells, Cultured, Cloning, Molecular, Drosophila melanogaster, HUMANS, Lupus Erythematosus, Systemic, Nucleic Acid Conformation, Nucleic Acid Hybridization, Ribonuclease T1, Ribonucleoproteins, RNA, RNA, Small Nuclear}, issn = {0305-1048}, author = {Mount, S M and Steitz, J A} } @article {49721, title = {Are snRNPs involved in splicing?}, journal = {Nature}, volume = {283}, year = {1980}, month = {1980 Jan 10}, pages = {220-4}, keywords = {Animals, Base Sequence, Cell Line, Chickens, Erythrocytes, HUMANS, Liver, Lupus Erythematosus, Systemic, Molecular Weight, Nucleic Acid Precursors, Nucleoproteins, Ribonucleoproteins, RNA, Heterogeneous Nuclear, Species Specificity}, issn = {0028-0836}, author = {Lerner, M R and Boyle, J A and Mount, S M and Wolin, S L and Steitz, J A} }