Hengge-Aronis R, Lange R, Henneberg N, Fischer D
Department of Biology, University of Konstanz, Germany.
J Bacteriol. 1993 Jan;175(1):259-65. doi: 10.1128/jb.175.1.259-265.1993.
The rpoS gene, which encodes a putative alternative sigma factor (sigma S), is essential for the expression of a variety of stationary-phase-induced genes as well as for stationary-phase-specific multiple-stress resistance. As previously shown for the otsA and otsB genes (R. Hengge-Aronis, W. Klein, R. Lange, M. Rimmele, and W. Boos, J. Bacteriol. 173:7918-7924, 1991), we demonstrate here that additional rpoS-controlled genes (bolA, csi-5) as well as at least 18 proteins on two-dimensional O'Farrell gels could be induced in growing cells by osmotic upshift via an rpoS-dependent mechanism. Also, rpoS-dependent thermotolerance and resistance against hydrogen peroxide could be osmotically stimulated. In contrast, the expression of glgS, while exhibiting strong stationary-phase induction, was only weakly increased by elevated osmolarity, and several rpoS-dependent proteins previously identified on two-dimensional gels were not osmotically induced. During osmotic induction of rpoS-dependent genes, rpoS transcription and the level of sigma S remained unchanged. We conclude that osmotically regulated genes represent a subfamily within the rpoS regulon that requires differential regulation in addition to that provided by sigma S.
rpoS基因编码一种假定的替代σ因子（σS），对于多种稳定期诱导基因的表达以及稳定期特异性多重胁迫抗性至关重要。正如之前对otsA和otsB基因所显示的那样（R. Hengge-Aronis、W. Klein、R. Lange、M. Rimmele和W. Boos，《细菌学杂志》173:7918 - 7924，1991年），我们在此证明，通过rpoS依赖机制，在生长细胞中，额外的rpoS调控基因（bolA、csi - 5）以及二维O'Farrell凝胶上的至少18种蛋白质可通过渗透压升高诱导产生。此外，rpoS依赖的耐热性和对过氧化氢的抗性也可被渗透压刺激。相比之下，glgS的表达虽然在稳定期有强烈诱导，但仅在渗透压升高时微弱增加，并且先前在二维凝胶上鉴定出的几种rpoS依赖蛋白质未被渗透压诱导。在rpoS依赖基因的渗透压诱导过程中，rpoS转录和σS水平保持不变。我们得出结论，渗透压调控基因代表rpoS调控子内的一个亚家族，除了σS提供的调控外，还需要差异调控。
