Antagonistic regulation of motility and transcriptome expression by RpoN and RpoS in Escherichia coli
Antagonistic regulation of motility and transcriptome expression by RpoN and RpoS in Escherichia coli
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DOI：
10.1111/j.1365-2958.2010.07449.x
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发表时间：
2011-01-01
影响因子：
3.6
通讯作者：
Schellhorn, Herb
中科院分区：
文献类型：
--
作者：
Dong, Tao;Yu, Rosemary;Schellhorn, Herb
细菌通常具有多个sigma因子，基于结构和功能的相似性，分为两个家族：sigma 70和sigma N。许多研究已经揭示了sigma 70家族中sigma因子的竞争，而sigma N和sigma 70家族之间的竞争尚未得到充分探讨。在这里，我们报告了两个替代西格玛因子，西格玛N（RpoN）和西格玛70家族蛋白质西格玛S（RpoS）之间的基因表达的全局拮抗作用。发现rpoS和rpoN中的突变对许多细胞性状产生负向影响，例如鞭毛基因的表达、在贫氮源上的sigma N控制的生长以及sigma S指导的酸性磷酸酶AppA的表达。转录组分析表明，RpoN调节子中约60%的基因受到相互RpoS的控制。此外，RpoN的丢失导致RpoS水平增加，而RpoN水平不受rpoS突变的影响。鞭毛σ F因子（FliA）（另一种σ 70家族蛋白）的表达受RpoN正控制，但受RpoS负控制。RpoN的这种阳性控制可能是通过鞭毛调节因子FlhDC介导的，FlhDC的表达是RpoN依赖性的。这些发现揭示了sigma N，sigma S和sigma F之间复杂的调节相互作用，其调节运动性，氮利用，应激反应和许多其他细胞功能。
P>Bacteria generally possess multiple sigma factors that, based on structural and functional similarity, divide into two families: sigma 70 and sigma N. Many studies have revealed sigma factor competition within the sigma 70 family, while the competition between sigma N and sigma 70 families has yet to be fully explored. Here we report a global antagonistic effect on gene expression between two alternative sigma factors, sigma N (RpoN) and a sigma 70 family protein sigma S (RpoS). Mutations in rpoS and rpoN were found to inversely affect a number of cellular traits, such as the expression of flagellar genes, sigma N-controlled growth on poor nitrogen sources, and sigma S-directed expression of acid phosphatase AppA. Transcriptome analysis reveals that about 60% of genes in the RpoN regulon are under reciprocal RpoS control. Furthermore, loss of RpoN led to increased levels of RpoS, while RpoN levels were unaffected by the rpoS mutation. Expression of the flagellar sigma F factor (FliA), another sigma 70 family protein, is controlled positively by RpoN but negatively by RpoS. This positive control by RpoN is likely mediated through the flagellar regulator FlhDC, whose expression is RpoN-dependent. These findings unveil a complex regulatory interaction among sigma N, sigma S and sigma F, which modulates motility, nitrogen utilization, stress response and many other cellular functions.