Lodwick D, Strike P
Department of Genetics and Microbiology, Liverpool University, UK.
Mol Gen Genet. 1991 Sep;229(1):27-30. doi: 10.1007/BF00264209.
Mutagenic DNA repair is a function of many naturally occurring plasmids belonging to several different incompatibility groups. A DNA probe corresponding to the impCAB operon of the IncI1 plasmid TP110, which encodes such functions, was used to investigate the distribution of homologous sequences in both related and unrelated plasmids. Southern blotting was used to demonstrate considerable sequence conservation amongst a number of plasmid types, with imp-related sequences being found on plasmids belonging to the I1, I1/B, B and FIV incompatibility groups. However, no homology was detected amongst plasmids of the N and L/M incompatibility groups, many of which carry functionally similar gene clusters. It appears that sequences determining mutagenic repair functions have been largely conserved within any one incompatibility group, but that significant divergent evolution has occurred between groups.
诱变DNA修复是许多属于不同不相容群的天然存在质粒的一种功能。与IncI1质粒TP110的impCAB操纵子相对应的DNA探针（该操纵子编码此类功能）被用于研究相关和不相关质粒中同源序列的分布。Southern印迹法被用于证明许多质粒类型之间存在相当程度的序列保守性，在属于I1、I1/B、B和FIV不相容群的质粒上发现了与imp相关的序列。然而，在N和L/M不相容群的质粒之间未检测到同源性，其中许多质粒携带功能相似的基因簇。看来决定诱变修复功能的序列在任何一个不相容群内已基本保守，但不同群之间已发生了显著的趋异进化。
