Increase in cell viability by polyamines through stimulation of the synthesis of ppGpp regulatory protein and ω protein of RNA polymerase in Escherichia coli
Increase in cell viability by polyamines through stimulation of the synthesis of ppGpp regulatory protein and ω protein of RNA polymerase in Escherichia coli
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多胺通过刺激大肠杆菌中 RNA 聚合酶的 ppGpp 调节蛋白和 ω 蛋白的合成来提高细胞活力
DOI：
10.1016/j.biocel.2011.11.017
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发表时间：
2012
期刊：
影响因子：
--
通讯作者：
et al
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文献类型：
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作者：
Terui;Y.;et al
众所周知，多胺通过刺激由所谓的“多胺模块”编码的几种蛋白质的合成来促进细胞生长。我们最近报道，多胺还通过刺激核糖体调节因子（多胺调节因子的一个组成部分）的合成来增加细胞生长稳定期的细胞活力。因此，我们寻找与细胞活力有关的其他蛋白质，其合成受到多胺的刺激。研究发现，多胺在翻译水平上刺激ppGpp调节蛋白(SpoT)和RNA聚合酶ω蛋白(RpoZ)的合成。多胺刺激 SpoT 和 RpoZ 的合成是由于 spoT mRNA 中低效的起始密码子 UUG 以及 rpoZ mRNA 中 Shine-Dalgarno (SD) 序列的不寻常位置。因此，spoT 和 rpoZ 基因是参与细胞活力的多胺模块的组成部分。修饰的 spoT 和 rpoZ 基因的合成不受多胺影响，可防止多胺缺乏引起的细胞活力降低。在这些条件下，ppGpp 水平随着 SpoT 蛋白的增加而增加。结果表明，多胺刺激 SpoT 和 RpoZ 的合成，通过 SpoT 刺激 ppGpp 合成和 ppGpp-RpoZ 复合物调节 RNA 合成，对细胞活力发挥重要作用。
It is known that polyamines increase cell growth through stimulation of the synthesis of several kinds of proteins encoded by the so-called “polyamine modulon”. We recently reported that polyamines also increase cell viability at the stationary phase of cell growth through stimulation of the synthesis of ribosome modulation factor, a component of the polyamine modulon. Accordingly, we looked for other proteins involved in cell viability whose synthesis is stimulated by polyamines. It was found that the synthesis of ppGpp regulatory protein (SpoT) and ω protein of RNA polymerase (RpoZ) was stimulated by polyamines at the level of translation. Stimulation of the synthesis of SpoT and RpoZ by polyamines was due to an inefficient initiation codon UUG in spoT mRNA and an unusual location of a Shine–Dalgarno (SD) sequence in rpoZ mRNA. Accordingly, the spoT and rpoZ genes are components of the polyamine modulon involved in cell viability. Reduced cell viability caused by polyamine deficiency was prevented by modified spoT and rpoZ genes whose synthesis was not influenced by polyamines. Under these conditions, the level of ppGpp increased in parallel with increase of SpoT protein. The results indicate that polyamine stimulation of synthesis of SpoT and RpoZ plays important roles for cell viability through stimulation of ppGpp synthesis by SpoT and modulation of RNA synthesis by ppGpp–RpoZ complex.