title: Chicken CD1 genes are located in the MHC: CD1 and endothelial protein C receptor genes constitute a distinct subfamily of class-I-like genes that predates the emergence of mammals.
abstract: Mammals have several major histocompatibility complex (MHC) class-I-like genes. Although some of them are assumed to have originated before the emergence of mammals, the origin of class-I-like genes is poorly understood. We analyzed here the recently released chicken draft genome sequence and identified two families of class-I-like genes: CD1 and PROCR (the gene for the endothelial protein C receptor). Chickens have two CD1 genes, designated CD1.1 and CD1.2, located in tandem approximately 840 bp apart from each other. Chicken CD1.1 and CD1.2 are neither group 1- nor group 2-like, indicating that the two groups of CD1 emerged in a mammalian lineage. Although the database provides no information as to their chromosomal localization, we found that chicken CD1 genes are located adjacent to the previously characterized MHC B system contig on chromosome 16. We confirmed the linkage of CD1 to the B system by dual-color fluorescence in situ hybridization. Chickens have a single copy of PROCR. Among known class-I-like genes, PROCR is most closely related to CD1, indicating that CD1 and PROCR constitute a distinct subfamily of class-I-like genes that predates the emergence of mammals.
authors.affiliation: Department of Pathology, Division of Pathophysiological Science, Hokkaido University Graduate School of Medicine, Sapporo, Japan.
authors.forename: Takako
authors.initials: T
authors.lastname: Maruoka
authors.forename: Hideyuki
authors.initials: H
authors.lastname: Tanabe
authors.forename: Marin
authors.initials: M
authors.lastname: Chiba
authors.forename: Masanori
authors.initials: M
authors.lastname: Kasahara
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D015703:Antigens, CD; D018949:Antigens, CD1 / Q000235:genetics*; D001483:Base Sequence; D002645:Chickens / Q000235:genetics*; D002874:Chromosome Mapping; D018076:DNA, Complementary / Q000302:isolation & purification; D000074283:Endothelial Protein C Receptor; D004730:Endothelium, Vascular / Q000378:metabolism*; D005805:Genes, MHC Class I; D006023:Glycoproteins / Q000235:genetics; D008285:Major Histocompatibility Complex; D008969:Molecular Sequence Data; D011956:Receptors, Cell Surface
chemical_list: D015703:Antigens, CD; D018949:Antigens, CD1; D018076:DNA, Complementary; D000074283:Endothelial Protein C Receptor; D006023:Glycoproteins; C478370:PROCR protein, human; D011956:Receptors, Cell Surface