The Myxococcus xanthus socE and csgA genes are regulated by the stringent response
The Myxococcus xanthus socE and csgA genes are regulated by the stringent response
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DOI：
10.1046/j.1365-2958.2000.02039.x
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发表时间：
2000-08-01
影响因子：
3.6
通讯作者：
Shimkets, LJ
中科院分区：
文献类型：
--
作者：
Crawford, EW;Shimkets, LJ
破坏黄色粘球菌 socE 基因可以绕过 CsgA 介导的细胞接触依赖性 C 信号系统的要求，并恢复子实体形态发生和孢子分化。 socE基因已通过遗传互补得到鉴定、克隆和测序。 SocE 具有高度碱性、独特性，预计是一种分子大小为 53.6 kDa 的可溶性蛋白质。 socE 和 csgA 基因在 M. xanthus 生命周期中具有相反的转录模式。 socE 表达在生长细胞中较高，并在发育早期阶段下降。 csgA 的表达在营养细胞中较低，并在发育过程中增加。 socE 转录受到严格反应的负调控，严格反应是 M. xanthus 中的主要氨基酸感应途径。 relA 无效突变消除了严格反应，防止了通常在发育开始时观察到的 socE 表达下降。 CsgA 受严格反应正向调节，并受 socE 负向调节。 relA 突变实际上消除了发育过程中的 csgA 表达。大肠杆菌中 socE 的表达导致 relA(-) 细胞在稳定期迅速丧失活力，表明与严格反应有关。
Disruption of the Myxococcus xanthus socE gene bypasses the requirement for the cell contact-dependent C-signalling system mediated by CsgA and restores fruiting body morphogenesis and spore differentiation. The socE gene has been identified by genetic complementation, cloned and sequenced. SocE is highly basic, unique and is predicted to be a soluble protein with a molecular size of 53.6 kDa. The socE and csgA genes have opposite transcription patterns during the M. xanthus life cycle. socE expression is high in growing cells and declines during the early stages of development. Expression of csgA is low in vegetative cells and increases during development. socE transcription is negatively regulated by the stringent response, the major amino acid-sensing pathway in M. xanthus. A relA null mutation, which eliminates the stringent response, prevents the decline in socE expression normally observed at the onset of development. CsgA is positively regulated by the stringent response and is negatively regulated by socE. A relA mutation virtually eliminates developmental csgA expression. Expression of socE in Escherichia coli leads to a rapid loss of viability in relA(-) cells during stationary phase, suggesting a relationship with the stringent response.