@article {49595,
	title = {Developmental expression of chicken FOXN1 and putative target genes during feather development.},
	volume = {58},
	year = {2014},
	month = {2014},
	pages = {57-64},
	abstract = {<p>FOXN1 is a member of the forkhead box family of transcription factors. FOXN1 is crucial for hair outgrowth and thymus differentiation in mammals. Unlike the thymus, which is found in all amniotes, hair is an epidermal appendage that arose after the last shared common ancestor between mammals and birds, and hair and feathers differ markedly in their differentiation and gene expression. Here, we show that FOXN1 is expressed in embryonic chicken feathers, nails and thymus, demonstrating an evolutionary conservation that goes beyond obvious homology. At embryonic day (ED) 12, FOXN1 is expressed in some feather buds and at ED13 expression extends along the length of the feather filament. At ED14 FOXN1 mRNA is restricted to the proximal feather filament and is not detectable in distal feather shafts. At the base of the feather, FOXN1 is expressed in the epithelium of the feather sheath and distal barb and marginal plate, whereas in the midsection FOXN1 transcripts are mainly detected in the barb plates of the feather filament. FOXN1 is also expressed in claws; however, no expression was detected in skin or scales. Despite expression of FOXN1 in developing feathers, examination of chick homologs of five putative mammalian FOXN1 target genes shows that, while these genes are expressed in feathers, there is little similarity to the FOXN1 expression pattern, suggesting that some gene regulatory networks may have diverged during evolution of epidermal appendages.</p>},
	keywords = {Amino Acid Sequence, Animals, Biological Evolution, Blotting, Western, Cell Differentiation, Cells, Cultured, Chick Embryo, Chickens, Cloning, Molecular, Embryo, Nonmammalian, Epidermis, Feathers, Forkhead Transcription Factors, Gene Expression Regulation, Developmental, In Situ Hybridization, Molecular Sequence Data, Morphogenesis, Phylogeny, Real-Time Polymerase Chain Reaction, Reverse Transcriptase Polymerase Chain Reaction, RNA, Messenger, Sequence Homology, Amino Acid},
	issn = {1696-3547},
	doi = {10.1387/ijdb.130023sy},
	author = {Darnell, Diana K and Zhang, Li S and Hannenhalli, Sridhar and Yaklichkin, Sergey Y}
}
@article {49628,
	title = {Detection of alloantigens during preimplantation development and early trophoblast differentiation in the mouse by immunoperoxidase labeling.},
	journal = {J Exp Med},
	volume = {143},
	year = {1976},
	month = {1976 Feb 1},
	pages = {348-59},
	abstract = {<p>An immunoperoxidase-labeling technique allowing visualization of antibody binding to the cell surface at the electron microscopical level has been employed an an analysis of H-2 and non-H-2 alloantigen expression on the early mouse embryo. The presence of non-H-2 antigenic determinants has been confirmed on eight-cell, morula, and blastocyst stages of development. Contrary to previous reports, however, low levels of H-2 antigen have also been detected on the blastocyst. This is the earliest stage at which H-2 has been shown to be expressed on the fertilized mouse egg and may reflect the greater resolution of the immunoperoxidase technique. Using two different models to study the critical peri-implantation stages, those of experimentally induced blastocyst activation and blastocyst outgrowth in vitro, it has been demonstrated that antigen loss occurs on the trophectoderm at the time of implantation, and that this is not necessarily dependent upon maternal influence. It is suggested that the loss may be an important factor in the prevention of maternal immune rejection during the establishment of the fetal allograft. The two major components of the early postimplantation conceptus display a striking differential in antigenic status. The embryonic sac shows a high degree of peroxidase labeling, while the ectoplacental cone trophoblast is unlabeled. These findings add support to the concept of antigenic neutrality of the early trophoblast and its role in the maintenance of a normal fetomaternal immunological equilibrium.</p>},
	keywords = {Animals, Binding Sites, Antibody, Blastocyst, Cell Differentiation, Cell Membrane, Embryo Implantation, Embryonic Development, Epitopes, Female, Histocompatibility Antigens, HLA Antigens, Horseradish Peroxidase, Mice, Mice, Inbred Strains, Pregnancy, Pregnancy, Animal, Trophoblasts},
	issn = {0022-1007},
	author = {Searle, R F and Sellens, M H and Elson, J and Jenkinson, E J and Billington, W D}
}
