XerCD/dif位点特异性重组

Progress on XerCD/dif site-specific recombination

大约10%~15%的大肠杆菌在染色体复制过程中会形成染色体二聚体。大肠杆菌染色体编码的重组酶XerC和XerD作用于染色体复制终点区的dif序列,以同源重组的方式将染色体二聚体解离为单体,使细菌得以正常复制分裂。编码霍乱毒素的噬菌体CTXΦ以位点特异的方式整合入霍乱弧菌染色体,但其基因组中不含有任何重组酶基因,其整合过程需要细菌染色体编码的XerC和XerD重组酶,且整合位点与大肠杆菌dif序列相似。XerCD重组酶基因和dif位点在细菌染色体广泛存在,表明其可能是染色体二聚体解离,噬菌体及其他外源基因成分整合入染色体过程中一种广泛存在的途径。文章对XerCD/dif位点特异性重组在细菌染色体二聚体解离。

In Escherichia coli,10% to 15% of growing bacteria produce chromosome dimers during DNA replication.These dimers are resolved by XerC and XerD,two chromosome recombinases that target the dif sequence in the replication terminus of chromosome.Phage CTXΦ integrates into vibrio cholerae chromosome in a site-specific manner.However,CTXΦ genome does not encode any recombinase,while recombinase XerC and XerD,which is coded by vibrio cholerae chromosome are required for the integration of CTXΦ into the vibrio cholerae chromosome.The CTXΦ integration site overlaps with the dif site.The wide distribution of XerCD recombinase and dif site among bacteria genome suggests that it may be universal in resolve of chromosome dimers and phage integration.In this article,we reviewed the research progresses on chromosome dimer resolve and phage integration through XerCD/dif site-specific recombination