Navarro-Lloréns Juana María, Martínez-García Esteban, Tormo Antonio
Departamento de Bioquímica y Biología Molecular I, Facultad de Ciencias Biológicas, Universidad Complutense de Madrid, 28040 Madrid, Spain.
Arch Microbiol. 2002 Dec;179(1):33-41. doi: 10.1007/s00203-002-0493-4. Epub 2002 Oct 31.
The upstream region of the Enterobacter cloacae strain CECT960 rpoS gene was sequenced. An IS 10R element was found within the nlpD gene, between rpoSp and rpoS. The rpoS promoter, although functional, did not drive transcription of the gene in this strain. However, rpoS transcription depended on this promoter in strains that lacked the insertion sequence in nlpD. rpoSp showed growth-phase-dependent, sigma(S)-independent regulation. Transcription from rpoSp was strongly inhibited by glucose even though it was cAMP-receptor-protein (CRP)-independent. Its functionality was also independent of both integration host factor (IHF) and the alarmone ppGpp. RpoS-dependent resistance to some environmental stresses showed a quantitative response to RpoS levels under some conditions (alkaline pH and high osmolarity) but not others (acidic pH, high temperature, and UV irradiation).
对阴沟肠杆菌CECT960菌株rpoS基因的上游区域进行了测序。在nlpD基因内、rpoSp和rpoS之间发现了一个IS 10R元件。rpoS启动子虽然具有功能，但在该菌株中并未驱动该基因的转录。然而，在nlpD中缺乏插入序列的菌株中，rpoS转录依赖于该启动子。rpoSp表现出与生长阶段相关的、不依赖于σ(S)的调控。即使rpoSp不依赖于环磷酸腺苷受体蛋白(CRP)，葡萄糖也会强烈抑制其转录。其功能也独立于整合宿主因子(IHF)和警报素ppGpp。在某些条件下(碱性pH值和高渗透压)，RpoS依赖性对某些环境压力的抗性对RpoS水平表现出定量反应，但在其他条件下(酸性pH值、高温和紫外线照射)则不然。
