IDENTIFICATION OF TRANSCRIPTIONAL START SITES AND THE ROLE OF PPGPP IN THE EXPRESSION OF RPOS, THE STRUCTURAL GENE FOR THE SIGMA(S) SUBUNIT OF RNA-POLYMERASE IN ESCHERICHIA-COLI
IDENTIFICATION OF TRANSCRIPTIONAL START SITES AND THE ROLE OF PPGPP IN THE EXPRESSION OF RPOS, THE STRUCTURAL GENE FOR THE SIGMA(S) SUBUNIT OF RNA-POLYMERASE IN ESCHERICHIA-COLI
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DOI：
10.1128/jb.177.16.4676-4680.1995
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发表时间：
1995-08-01
影响因子：
3.2
通讯作者：
HENGGEARONIS, R
中科院分区：
文献类型：
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作者：
LANGE, R;FISCHER, D;HENGGEARONIS, R
rpoS是RNA聚合酶σ（5）亚基的结构基因，其控制大肠杆菌中大量基因的表达，所述基因在进入稳定期期间或响应于增加的介质渗透压浓度而被诱导。使用引物延伸实验和rpoS上游区域的5 ′缺失分析的组合，我们发现rpoS的转录主要由位于rpoS上游nlpD基因内的单个启动子（rpoSp（1））驱动（两个相对较弱的nlpD启动子导致在指数生长期早期rpoS表达水平较低）。此外，我们证明，在ppGpp缺陷型relA spoT突变体中，转录和翻译rpoS：：lacZ融合体的表达以及源自rpoSp的rpoS mRNA的水平均强烈降低。然而，用5'缺失构建体进行的实验表明，缺乏ppGpp确实影响转录延伸而不是起始。
rpoS is the structural gene for the sigma(5) subunit of RNA polymerase which controls the expression of a large number of genes in Escherichia coli that are induced during entry into stationary phase or in response to increased medium osmolarity, Using a combination of primer extension experiments and a 5' deletion analysis of the region upstream of rpoS, we show that rpoS transcription is mainly driven by a single promoter (rpoSp(1)) located within the nlpD gene upstream of rpoS (the two relatively weak nlpD promoters contribute to the low level of rpoS expression during early exponential phase), In addition, we demonstrate that the expression of both transcriptional and translational rpoS::lacZ fusions as well as the level of rpoS mRNA originating at rpoSp, is strongly reduced in ppGpp-deficient relA spoT mutants. However, experiments with the 5' deletion constructs indicate that a lack of ppGpp does affect transcriptional elongation rather than initiation.