title: Isolation and mapping the chicken zona pellucida genes: an insight into the evolution of orthologous genes in different species.
abstract: The avian oocyte is surrounded by a specialized extracellular glycoproteinaceous matrix, the perivitelline membrane, which is equivalent to the zona pellucida (ZP) in mammals and the chorion in teleosts. A number of related ZP genes encode the proteins that make up this matrix. These proteins play an important role in the sperm/egg interaction and may be involved in speciation. The human genome is known to contain ZP1, ZP2, ZP3, and ZPB genes, while a ZPAX gene has also been identified in Xenopus. The rapid evolution of these genes has confused the nomenclature and thus orthologous relationships across species. In order to clarify these homologies, we have identified ZP1, ZP2, ZPC, ZPB, and ZPAX genes in the chicken and mapped them to chromosomes 5, 14, 10, 6, and 3, respectively, establishing conserved synteny with human and mouse. The amino acid sequences of these genes were compared to the orthologous genes in human, mouse, and Xenopus, and have given us an insight into the evolution of these genes in a variety of different species. The presence of the ZPAX gene in the chicken has highlighted a pattern of probable gene loss by deletion in mouse and gene inactivation by deletion, and base substitution in human.
authors.affiliation: Division of Genomics and Bioinformatics, Roslin Institute, Roslin (Edinburgh), Midlothian EH25 9PS, Scotland, United Kingdom. Jacqueline.Smith@bbsrc.ac.uk
authors.forename: Jacqueline
authors.initials: J
authors.lastname: Smith
authors.forename: Ian R
authors.initials: IR
authors.lastname: Paton
authors.forename: David C
authors.initials: DC
authors.lastname: Hughes
authors.forename: David W
authors.initials: DW
authors.lastname: Burt
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002645:Chickens / Q000235:genetics* / Q000378:metabolism; D002874:Chromosome Mapping; D004527:Egg Proteins / Q000235:genetics*; D019143:Evolution, Molecular; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D008562:Membrane Glycoproteins / Q000235:genetics*; D051379:Mice; D008969:Molecular Sequence Data; D010802:Phylogeny; D011956:Receptors, Cell Surface / Q000235:genetics*; D016415:Sequence Alignment; D017385:Sequence Homology; D013084:Sperm-Ovum Interactions / Q000235:genetics; D015044:Zona Pellucida / Q000378:metabolism*; D000072216:Zona Pellucida Glycoproteins
chemical_list: D004527:Egg Proteins; D008562:Membrane Glycoproteins; D011956:Receptors, Cell Surface; C000606514:ZP1 protein, human; C000606515:ZP2 protein, human; C000606517:ZP3 protein, human; D000072216:Zona Pellucida Glycoproteins; C000606519:Zp1 protein, mouse; C000606520:Zp2 protein, mouse; C000606521:Zp3 protein, mouse