Genes for the SMC family proteins in a common vole Microtus arvalis

Genes for four subfamilies of SMC (structural maintenance of chromosomes) p roteins have been isolated from the genome of a common vole Microtus arvali s. The high degree of homology between representatives of each SMC protein subfamily of different classes of organisms has been demonstrated. The full -sized copy of a mammalian gene encoding SMC4 protein has been isolated and analyzed for the first time. The SMC proteins enter into the composition o f complexes responsible for cohesion of sister chromatids, formation of mit otic chromosomes, recombination, DNA repair, and regulation of gene express ion. We discuss the possible participation of the SMC proteins in inactivat ion of the X chromosome in mammalian females. Common voles of genus Microtu s group "arvalis" serve a unique model for the study of the inactivation pr ocess.