title: Evolutionary pathways of an ancient gene recX.
abstract: RecX is a regulator of RecA activity by interacting with RecA protein or RecA filaments. Genes encoding RecX were found in genomes of a wide diversity of bacteria and some plants (e.g., Arabidopsis thaliana and Oryza sativa). Our comparative genome analysis showed that although members of the RecX family are found in many bacterial species, they are not found in archaea and the only gene found in eukaryotes is likely derived from bacteria genomes. It is therefore proposed that RecX is of bacterial origin, and the gene had presented in the common ancestor of bacteria. Moreover, bacterial RecX and plant RecX domain are homologues, and RecX domain in plants may have derived from bacteria via unknown pathways. Plant RecX-like protein was formed by a gene fusion event between a unique N-terminal domain of unknown origin and RecX domain within plant cells. Finally, three possible evolutionary pathways from bacteria to plant were discussed.
authors.affiliation: Institute of Nuclear-Agricultural Sciences, Zhejiang University, Kaixuan Road 268, Hangzhou 310029, China.
authors.forename: Jun
authors.initials: J
authors.lastname: Lin
authors.forename: Zhong-Zhong
authors.initials: ZZ
authors.lastname: Chen
authors.forename: Bing
authors.initials: B
authors.lastname: Tian
authors.forename: Yue-Jin
authors.initials: YJ
authors.lastname: Hua
mesh_terms: D001426:Bacterial Proteins / Q000145:classification / Q000235:genetics / Q000378:metabolism*; D004260:DNA Repair; D019143:Evolution, Molecular; D010802:Phylogeny; D011938:Rec A Recombinases / Q000235:genetics; D011995:Recombination, Genetic
chemical_list: D001426:Bacterial Proteins; C430523:RecX protein, Xanthomonas campestris; D011938:Rec A Recombinases