Phase variation in Salmonella: analysis of Hin recombinase and hix recombination site interaction in vivo.
Phase variation in Salmonella: analysis of Hin recombinase and hix recombination site interaction in vivo.
复制标题
沙门氏菌的相变：体内 Hin 重组酶和 hix 重组位点相互作用的分析。
DOI：
10.1101/gad.2.8.937
复制
发表时间：
1988
影响因子：
10.5
通讯作者：
Simon,MI
中科院分区：
文献类型：
--
作者：
Hughes,KT;Youderian,P;Simon,MI
使用基于噬菌体P22的挑战阶段选择来表征沙门氏菌Hin重组酶与野生型hixL和hixR重组位点以及突变体和合成hix序列在体内的结合。Hin重组酶与hixL或hixR重组位点结合，并抑制攻击噬菌体系统中上游启动子的转录。Hin介导的阻遏是由于Hin在结合之前或在hix操纵基因位点的结合过程中结合到多聚体中（协同性）。当hix 13-bp半位点通过在它们之间插入4 bp而旋转到DNA螺旋的相对侧时，Hin多聚体抑制转录的能力被消除。在半位点之间插入Ibp降低了总体阻遏。Hin还结合hixL半位点之一来抑制转录，但仅当细胞中存在高水平的Hin蛋白时。已经在hix位点中鉴定了损害Hin结合的突变。在hix位点的26个bp中有5个是关键的;在这5个位置具有碱基对取代的位点显示出大大降低的结合。三个额外的碱基对对结合的贡献很小。这些结果与Hin和hix位点之间的体外结合研究结果一致。
The bacteriophage P22-based challenge phase selection was used to characterize the binding of Salmonella Hin recombinase to the wild-type hixL and hixR recombination sites, as well as to mutant and synthetic hix sequences in vivo. Hin recombinase binds to the hixL or hixR recombination sites and represses transcription from an upstream promoter in the challenge phage system. Hin-mediated repression results from Hin associating into multimers either prior to binding or during the binding process at the hix operator sites (cooperativity). The ability of Hin multimers to repress transcription is eliminated when the hix 13-bp half-sites are rotated to opposite sides of the DNA helix by inserting 4 bp between them. Insertion of 1 bp between half-sites reduces overall repression. Hin also binds one of the hixL half-sites to repress transcription, but only when high levels of Hin protein are present in the cell. Mutations have been identified in the hix sites that impair Hin binding. Five of the 26 bp in the hix sites are critical; sites with base-pair substitutions at these five positions show greatly reduced binding. Three additional base pairs make minor contributions to binding. These results are consistent with the results of binding studies between Hin and the hix sites in vitro.