Induction of σB-dependent general stress genes by amino acid starvation in a spo0H mutant of Bacillus subtilis
Induction of σB-dependent general stress genes by amino acid starvation in a spo0H mutant of Bacillus subtilis
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DOI：
10.1016/s0378-1097(01)00187-2
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发表时间：
2001-05-30
影响因子：
2.1
通讯作者：
Hecker, M
中科院分区：
文献类型：
--
作者：
Eymann, C;Hecker, M
单独依赖sigma (B)的基因，如gsiB和gspA，在氨基酸缺乏的野生型细胞中没有明显的诱导作用，因为氨基酸饥饿不会触发sigma (B)的激活。一般应激基因yvyD受到sigma (B)和sigma (H)的控制，因此在sigma (H)依赖的启动子上表现出对氨基酸饥饿的诱导反应。令人惊讶的是，在缺乏sigma (H)活性的菌株中，YvyD、GsiB和GspA蛋白在氨基酸匮乏的细胞中被显著诱导。转录研究提供的证据表明，在氨基酸饥饿期间，spo0H突变体确实诱导了sigma (B)依赖性转录，并且依赖于RsbP而不依赖于RsbU，这表明这种诱导不需要胁迫信号转导。在spo0A缺失突变体的氨基酸缺乏细胞中观察到类似的sigma (B)活化现象。spo0H突变体中的sigma (B)依赖性转录进一步需要一个活跃的RelA蛋白，该蛋白负责在氨基酸饥饿（严格反应）后对看家基因的强烈抑制。我们的数据表明，在缺乏sigma (H)和引发严格反应的条件下，依赖rbp的活性sigma (B)水平可以更有效地竞争增加的游离RNA聚合酶核心酶水平，从而诱导可能最强的sigma (B)依赖基因。(C) 2001年欧洲微生物学会联合会。Elsevier Science B.V.版权所有。
Solely sigma (B)-dependent genes like gsiB and gspA are not significantly induced in amino acid-starved wild-type cells, since amino acid starvation does not trigger activation of sigma (B). The general stress gene yvyD is subject to the control of both sigma (B) and sigma (H) therefore displaying induction in response to amino acid starvation at the sigma (H)-dependent promoter. Surprisingly, the proteins YvyD, GsiB and GspA were significantly induced in amino acid-starved cells of a strain lacking sigma (H) activity. Transcriptional studies provided evidence that sigma (B)-dependent transcription is indeed induced in a spo0H mutant during amino acid starvation and depends on RsbP but not on RsbU indicating that the stress signal transduction is not required for this induction. A similar phenomenon of sigma (B) activation was observed in amino acid-starved cells of a spo0A deletion mutant. The sigma (B)-dependent transcription in a spo0H mutant further needs an active RelA protein which is responsible for strong repression of house-keeping genes after amino acid starvation (stringent response). Our data indicate that in the absence of sigma (H) and under conditions which provoke the stringent response, RsbP-dependent levels of active sigma (B) can more effectively compete for increased levels of free RNA polymerase core enzyme leading to the induction of the probably strongest sigma (B)-dependent genes. (C) 2001 Federation of European Microbiological Societies. Published by Elsevier Science B.V. All rights reserved.