title: Sequence, organization, and evolution of Rh50 glycoprotein genes in nonhuman primates.
abstract: The human RHAG locus encodes Rh50 glycoprotein, a polytopic protein that modulates expression of Rh antigens carried by Rh30 polypeptides. Rh50 is almost invariant, whereas Rh30 shows high polymorphism. To assess the relative conservation and phylogenetic relationship of RHAG genes, we characterized their protein expression, transcript structure, genomic organization, and noncoding regions (promoter and introns) in seven nonhuman primate species. Western blot showed that only ape Rh50 glycoproteins are recognized by the antibody 2D10 specific for the human counterpart. Analysis of RHAG gene and its transcript showed a high degree of sequence identity and features of interspecific diversity. The nonhuman primate RHAG genes are highly similar in promoter region and identical in exon-intron organization. Genomic sequencing identified one retro-transposon-like element in intron 2 and three types of Alu elements in intron 4 and 9, with varying copies of minisatellites. Reconstruction of coding and noncoding sequence trees revealed concordances and discordances with regard to the branching of RHAG-like genes in higher primates. A joined tree of Rh50 glycoproteins and Rh30 polypeptides shows that the former evolved at a rate about two times slower than the latter. Statistical tests demonstrated that at least a portion of the RHAG gene was subjected to a positive selection during evolution of anthropoids.
authors.affiliation: Laboratory of Biochemistry and Molecular Genetics, Lindsley F. Kimball Research Institute, New York Blood Center, New York, NY 10021, USA.
authors.forename: C H
authors.initials: CH
authors.lastname: Huang
authors.forename: Z
authors.initials: Z
authors.lastname: Liu
authors.forename: P A
authors.initials: PA
authors.lastname: Apoil
authors.forename: A
authors.initials: A
authors.lastname: Blancher
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001798:Blood Proteins / Q000235:genetics*; D015139:Blotting, Southern; D017124:Conserved Sequence; D004912:Erythrocytes / Q000502:physiology; D019143:Evolution, Molecular; D005091:Exons; D018628:Gene Dosage; D014644:Genetic Variation; D006023:Glycoproteins / Q000235:genetics*; D006801:Humans; D007438:Introns; D008562:Membrane Glycoproteins / Q000235:genetics; D008969:Molecular Sequence Data; D010802:Phylogeny; D011323:Primates / Q000235:genetics*; D011401:Promoter Regions, Genetic; D012204:Rh-Hr Blood-Group System; D017421:Sequence Analysis
chemical_list: D001798:Blood Proteins; D006023:Glycoproteins; D008562:Membrane Glycoproteins; C498523:RHAG protein, human; C066468:RHCE protein, human; D012204:Rh-Hr Blood-Group System