Lin Jun, Chen Zhong-Zhong, Tian Bing, Hua Yue-Jin
Institute of Nuclear-Agricultural Sciences, Zhejiang University, Kaixuan Road 268, Hangzhou 310029, China.
Gene. 2007 Jan 31;387(1-2):15-20. doi: 10.1016/j.gene.2006.07.031. Epub 2006 Aug 18.
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.
RecX通过与RecA蛋白或RecA丝相互作用来调节RecA的活性。在各种各样的细菌以及一些植物（如拟南芥和水稻）的基因组中发现了编码RecX的基因。我们的比较基因组分析表明，虽然RecX家族的成员存在于许多细菌物种中，但在古细菌中未发现，而在真核生物中发现的唯一基因可能源自细菌基因组。因此，有人提出RecX起源于细菌，并且该基因存在于细菌的共同祖先中。此外，细菌RecX和植物RecX结构域是同源的，植物中的RecX结构域可能通过未知途径源自细菌。植物类RecX蛋白是由植物细胞内一个未知来源的独特N端结构域与RecX结构域之间的基因融合事件形成的。最后，讨论了从细菌到植物的三种可能进化途径。
