Gasson M J, Willetts N S
J Bacteriol. 1977 Aug;131(2):413-20. doi: 10.1128/jb.131.2.413-420.1977.
Flac mutants insensitive to transfer inhibition by R factors. JR66a and R485 were isolated and characterized. Representative mutations were cis dominant and are therefore presumed to be at the sites of action, fisU and fisV, respectively, of the FinU and FinV transfer inhibition systems encoded by JR66a and R485. The mutants were used to confirm that the FinU and FinV fertility inhibition systems are different from each other and from the FinOP, FinQ, and FinW systems of R100, R62, and R455, respectively. Together with traO and fisQ mutants of Flac, the new mutants were also used to investigate the nature of the F fertility inhibition systems encoded by a further group of "unusual" Fin+ plasmids. Of these, two incompatibility group X plasmids were found to carry finO+ genes, and of five incompatibility group I plasmids, three encoded FinQ systems, one the FinU system, and one a new system (FinR). Transfer of a variety of derepressed F-like plasmids was inhibited by the FinQ, FinU, and FinV systems, but a quantitatively very different levels; this emphasizes the differences as well as the similarities between the conjugation systems of F-like plasmids.
对R因子介导的转移抑制不敏感的Flac突变体。分离并鉴定了JR66a和R485。代表性突变是顺式显性的，因此推测分别位于由JR66a和R485编码的FinU和FinV转移抑制系统的作用位点fisU和fisV处。这些突变体用于证实FinU和FinV育性抑制系统彼此不同，且分别与R100、R62和R455的FinOP、FinQ和FinW系统不同。与Flac的traO和fisQ突变体一起，这些新突变体还用于研究另一组“异常”Fin+质粒编码的F育性抑制系统的性质。其中，发现两个不相容群X质粒携带finO+基因，在五个不相容群I质粒中，三个编码FinQ系统，一个编码FinU系统，一个编码新系统（FinR）。多种去阻遏的F样质粒的转移受到FinQ、FinU和FinV系统的抑制，但抑制水平在数量上有很大差异；这强调了F样质粒接合系统之间的差异和相似性。
