...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Journal of bacteriology >Evidence for involvement of proteins HU and RpoS in transcription of the osmoresponsive proU operon in Escherichia coli.
【24h】

Evidence for involvement of proteins HU and RpoS in transcription of the osmoresponsive proU operon in Escherichia coli.

机译：蛋白质HU和RpoS参与大肠杆菌中渗透反应性proU操纵子转录的证据。

获取原文
   

获取外文期刊封面封底 >>

       
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

Transcription of the proU operon of Escherichia coli is induced several hundred-fold upon growth at elevated osmolarity, but the underlying mechanisms are incompletely understood. Three cis elements appear to act additively to mediate proU osmoresponsivity: (i) sequences around a promoter, P1, which is situated 250 bp upstream of the first structural gene proV; (ii) sequences around another (sigma 70-dependent) promoter, P2, which is situated 60 bp upstream of proV; and (iii) a negative regulatory element present within the proV coding region. These three cis elements are designated, respectively, P1R, P2R, and NRE. trans-acting mutants with partially derepressed proU expression have been obtained earlier, and a vast majority of the mutations affect the gene encoding the nucleoid protein HNS. In this study we employed a selection for trans-acting mutants with reduced proU+ expression, and we obtained a derivative that had suffered mutations in two separate loci designated dpeA and dpeB. The dpeB mutation caused a marked reduction in promoter P1 expression and was allelic to rpoS, the structural gene for the stationary-phase-specific sigma factor of RNA polymerase. Expression from P1 was markedly induced, in an RpoS-dependent manner, in stationary-phase cultures. In contrast to the behavior of the isolated P1 promoter, transcription from a construct carrying the entire proU cis-regulatory region (P1R plus P2R plus NRE) was not significantly affected by either growth phase or RpoS. The dpeA locus was allelic to hupB, which along with hupA encodes the nucleoid protein HU. hupA hupB double mutants exhibited a pronounced reduction in proU osmotic inducibility. HU appears to affect proU regulation through the P2R mechanism, whereas the effect of HNS is mediated through the NRE.
机译：大肠杆菌的proU操纵子在高渗透压下生长时被诱导数百倍的转录，但是其潜在的机理尚不完全清楚。三个顺式元件似乎起着加和作用，以介导proU渗透性响应：（i）启动子P1周围的序列，该序列位于第一个结构基因proV上游250 bp; （ii）位于proV上游60 bp的另一个（依赖sigma 70的）启动子P2周围的序列; （iii）在proV编码区内存在的负调控元件。这三个顺式元素分别指定为P1R，P2R和NRE。早已获得了部分被抑制的proU表达的反式突变体，绝大多数突变影响编码类核蛋白HNS的基因。在这项研究中，我们选择了具有减少的proU +表达的反式突变体，并获得了在两个分别命名为dpeA和dpeB的基因座中发生突变的衍生物。 dpeB突变导致启动子P1表达显着降低，并与rpoS等位基因等位基因，rpoS是RNA聚合酶固定相特异性sigma因子的结构基因。在稳定期培养中，以RpoS依赖性方式明显诱导了P1的表达。与分离的P1启动子的行为相反，从携带整个proU顺式调控区（P1R加P2R加NRE）的构建体的转录不受生长期或RpoS的影响。 dpeA基因座与hupB等位基因，后者与hupA一起编码类核蛋白HU。 hupA hupB双突变体在proU渗透诱导性上显示出明显的降低。 HU似乎通过P2R机制影响proU调节，而HNS的作用是通过NRE介导的。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号