Ohnuma M, Fujita N, Ishihama A, Tanaka K, Takahashi H
Institute of Molecular and Cellular Biosciences, The University of Tokyo, Yayoi 1-1-1, Bunkyo-ku, Tokyo 113-0032, Japan.
J Bacteriol. 2000 Aug;182(16):4628-31. doi: 10.1128/JB.182.16.4628-4631.2000.
sigma(38) (or sigma(S), the rpoS gene product) is a sigma subunit of RNA polymerase in Escherichia coli and directs transcription from a number of stationary-phase promoters as well as osmotically inducible promoters. In this study, we analyzed the function of the carboxy-terminal 16-amino-acid region of sigma(38) (residues 315 to 330), which is well conserved among the rpoS gene products of enteric bacterial species. Truncation of this region was shown to result in the loss of sigma activity in vivo using promoter-lacZ fusion constructs, but the mutant sigma(38) retained the binding activity in vivo to the core enzyme. The in vitro transcription analysis revealed that the transcription activity of sigma(38) holoenzyme under high potassium glutamate concentrations was significantly decreased by the truncation of the carboxy-terminal tail element.
σ（38）（或σ（S），rpoS基因产物）是大肠杆菌中RNA聚合酶的一个σ亚基，它指导来自多个稳定期启动子以及渗透诱导型启动子的转录。在本研究中，我们分析了σ（38）羧基末端16个氨基酸区域（残基315至330）的功能，该区域在肠道细菌物种的rpoS基因产物中高度保守。使用启动子-lacZ融合构建体表明，该区域的截短会导致体内σ活性丧失，但突变型σ（38）在体内仍保留与核心酶的结合活性。体外转录分析表明，羧基末端尾部元件的截短显著降低了高谷氨酸钾浓度下σ（38）全酶的转录活性。
