生物
西格玛因子
细胞生物学
RPO
运动性
生物膜
基因表达调控
基因表达
RNA聚合酶
大肠杆菌
遗传学
基因
发起人
细菌
作者
Christina Pesavento,Gisela Becker,Nicole Sommerfeldt,Alexandra Possling,Natalia Tschowri,Anika Mehlis,Regine Hengge
出处
期刊:Genes & Development
[Cold Spring Harbor Laboratory]
日期:2008-09-01
卷期号:22 (17): 2434-2446
被引量:321
摘要
During the transition from post-exponential to stationary phase, Escherichia coli changes from the motile-planktonic to the adhesive-sedentary "lifestyle." We demonstrate this transition to be controlled by mutual inhibition of the FlhDC/motility and sigma(S)/adhesion control cascades at two distinct hierarchical levels. At the top level, motility gene expression and the general stress response are inversely coordinated by sigma(70)/sigma(FliA)/sigma(S) competition for core RNA polymerase and the FlhDC-controlled FliZ protein acting as a sigma(S) inhibitor. At a lower level, the signaling molecule bis-(3'-5')-cyclic-diguanosine monophosphate (c-di-GMP) reduces flagellar activity and stimulates transcription of csgD, which encodes an essential activator of adhesive curli fimbriae expression. This c-di-GMP is antagonistically controlled by sigma(S)-regulated GGDEF proteins (mainly YegE) and YhjH, an EAL protein and c-di-GMP phosphodiesterase under FlhDC/FliA control. The switch from motility-based foraging to the general stress response and curli expression requires sigma(S)-modulated down-regulation of expression of the flagellar regulatory cascade as well as proteolysis of the flagellar master regulator FlhDC. Control of YhjH by FlhDC and of YegE by sigma(S) produces a fine-tuned checkpoint system that "unlocks" curli expression only after down-regulation of flagellar gene expression. In summary, these data reveal the logic and sequence of molecular events underlying the motile-to-adhesive "lifestyle" switch in E. coli.
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