title: Gene structure and evolution of testicular haploid germ cell-specific genes, Oxct2a and Oxct2b.
abstract: OXCT/SCOT is the rate-determining enzyme in ketolysis in mitochondria of many extrahepatic organs. Two testicular isoforms, Oxct2a and Oxct2b, are highly homologous and specifically expressed in haploid spermatids of the mouse. In this report, we analyzed the structure and evolution of Oxct2a and Oxct2b. Both Oxct2's are single-copy intronless genes, of which nucleotide sequences are conserved with Oxct, indicating that these genes are transposons generated from Oxct. A CpG island was found within both Oxct2's. Oxct2a and Oxct2b are located in the third introns of Bmp8a and Bmp8b, and they are positioned within a 240-kb region in a tail-to-tail orientation on chromosome 4. This structural feature was also conserved in a syntenic region of human 1p34.3. Structural similarity between mice and humans indicated that these two sets of genes were generated by a segmental gene duplication, which occurred before the primate-rodent split. Dot matrix and phylogenetic tree analyses demonstrated that multiple rounds of intrachromosomal gene conversion between the two loci occurred in each species independently.
authors.affiliation: Department of Science for Laboratory Animal Experimentation, Research Institute for Microbial Diseases, Osaka University, 3-1 Yamadaoka, Suita City, Osaka 565-0871, Japan.
authors.forename: Masayoshi
authors.initials: M
authors.lastname: Onishi
authors.forename: Teruo
authors.initials: T
authors.lastname: Yasunaga
authors.forename: Hiromitsu
authors.initials: H
authors.lastname: Tanaka
authors.forename: Yoshitake
authors.initials: Y
authors.lastname: Nishimune
authors.forename: Masami
authors.initials: M
authors.lastname: Nozaki
mesh_terms: D000818:Animals; D001483:Base Sequence; D015139:Blotting, Southern; D019485:Bone Morphogenetic Proteins / Q000378:metabolism; D002894:Chromosomes, Human, Pair 4 / Q000378:metabolism; D015256:Coenzyme A-Transferases / Q000235:genetics*; D018899:CpG Islands; D017931:DNA Primers / Q000737:chemistry; D018076:DNA, Complementary / Q000378:metabolism; D019143:Evolution, Molecular; D016678:Genome; D006238:Haploidy; D006801:Humans; D007438:Introns; D008297:Male; D051379:Mice; D008957:Models, Genetic; D008969:Molecular Sequence Data; D016366:Open Reading Frames; D010802:Phylogeny; D011061:Poly A / Q000378:metabolism; D012313:RNA / Q000737:chemistry; D017422:Sequence Analysis, DNA; D012689:Sequence Homology, Nucleic Acid; D013045:Species Specificity; D013087:Spermatids / Q000378:metabolism; D013737:Testis / Q000378:metabolism*; D014158:Transcription, Genetic
chemical_list: C405632:BMP8B protein, human; C485772:Bmp8a protein, mouse; D019485:Bone Morphogenetic Proteins; D017931:DNA Primers; D018076:DNA, Complementary; D011061:Poly A; D012313:RNA; D015256:Coenzyme A-Transferases; C021460:3-ketoacid CoA-transferase