title: A transposable element-mediated gene divergence that directly produces a novel type bovine Bcnt protein including the endonuclease domain of RTE-1.
abstract: Ruminant Bcnt protein with a molecular mass of 97 kDa (designated p97Bcnt) includes a region derived from the endonuclease domain of a retrotransposable element RTE-1. Human and mouse Bcnt proteins lack the corresponding region but have a highly conserved 82-amino acid region at the C-terminus that is not present in p97Bcnt. By screening a bovine BAC library, we found two more bcnt-related genes: human-type bcnt (h-type bcnt) and its processed pseudogene. Whereas the pseudogene is localized on chromosome 26, both bcntp97 and the h-type bcnt genes are found on bovine chromosome 18, a synteny region of human chromosome 16 on which human BCNT is localized. Complete nucleotide sequencing of the BAC clone reveals that the bcntp97 and h-type bcnt genes are located just 6 kb apart in a tandem manner. The two h-type bcnt and bcntp97genes are active at both the transcriptional level and the protein level. H-type bovine Bcnt is more like human BCNT than p97Bcnt, when compared at their N-terminal regions. However, phylogenetic analysis using the N-terminal region of the bcnt gene family revealed that the duplication of bovine genes occurred within the bovine lineage with significantly accelerated substitution in bcntp97. This acceleration was not ascribed definitely to positive selection. After duplication, one of the bovine bcnt genes recruited the endonuclease domain of an intronic RTE-1 repeat accompanied by the accelerated substitution at the 5'-ORF, resulting in creation of a novel type of Bcnt protein in bovine.
authors.affiliation: Mitsubishi Kagaku Institute of Life Sciences (MITILS), Tokyo, Japan. siwast@libra.ls.m-kagaku.co.jp
authors.forename: Shintaro
authors.initials: S
authors.lastname: Iwashita
authors.forename: Naoki
authors.initials: N
authors.lastname: Osada
authors.forename: Tomohito
authors.initials: T
authors.lastname: Itoh
authors.forename: Mariko
authors.initials: M
authors.lastname: Sezaki
authors.forename: Kenshiro
authors.initials: K
authors.lastname: Oshima
authors.forename: Etsuko
authors.initials: E
authors.lastname: Hashimoto
authors.forename: Yuko
authors.initials: Y
authors.lastname: Kitagawa-Arita
authors.forename: Ichiro
authors.initials: I
authors.lastname: Takahashi
authors.forename: Tohru
authors.initials: T
authors.lastname: Masui
authors.forename: Katsuyuki
authors.initials: K
authors.lastname: Hashimoto
authors.forename: Wojciech
authors.initials: W
authors.lastname: Makalowski
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002417:Cattle / Q000235:genetics*; D002874:Chromosome Mapping; D022202:Chromosomes, Artificial, Bacterial; D002885:Chromosomes, Human, Pair 16 / Q000235:genetics; D004251:DNA Transposable Elements; D004720:Endonucleases; D019143:Evolution, Molecular; D005091:Exons; D015723:Gene Library; D014644:Genetic Variation; D006801:Humans; D007438:Introns; D020084:Long Interspersed Nucleotide Elements; D051379:Mice; D008969:Molecular Sequence Data; D009687:Nuclear Proteins; D010750:Phosphoproteins / Q000235:genetics*; D011544:Pseudogenes; D018626:Retroelements / Q000235:genetics*; D012418:Ruminants / Q000235:genetics; D017386:Sequence Homology, Amino Acid
chemical_list: C104422:CFDP1 protein, human; D004251:DNA Transposable Elements; D009687:Nuclear Proteins; D010750:Phosphoproteins; D018626:Retroelements; D004720:Endonucleases