| Title | Factors Influencing Preferential Utilization of RNA Polymerase Containing Sigma-38 in Stationary-Phase Gene Expression in Escherichia coli |
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| Author | Eun Young Kim 1 , Min-Sang Shin 1 , Joon Haeng Rhee 1 and Hyon E. Choy 1 , * |
| Address | 1 Genome Research Center for Enteropathogenic Bacteria, and Dept. of Microbiology, Chonnam National University Medical College, Hak-1-Dong, Dong-Gu, Kwang-Ju, Korea 501-746 |
| Bibliography | Journal of Microbiology, 42(2),103-110, 2004, |
| DOI | |
| Key Words | RNA polymerase, 6S RNA, in vitro transcription, sigma factor |
| Abstract | In order to understand the molecular basis of selective expression of stationary-phase genes by RNA polymerase containing [sigma]^38 (E[sigma]^38) in Escherichia coli, we examined transcription from the stationaryphase promoters, katEP, bolAP, hdeABP, csgBAP, and mcbP, in vivo and in vitro. Although these promoters are preferentially recognized in vivo by E[sigma]^38, they are transcribed in vitro by both E[sigma]^38 and E[sigma]^70 containing the major exponential [sigma], [sigma]^70. In the presence of high concentrations of glutamate salts, however, only E[sigma]^38 was able to efficiently transcribe from these promoters, which supports the concept that the promoter selectivity of [sigma]^38 -containing RNA polymerase is observed only under specific reaction conditions. The examination of 6S RNA, which is encoded by the ssr1 gene in vivo, showed that it reduced E[sigma]^70 activity during the stationary phase, but this reduction of activity did not result in the elevation of E[sigma]^38 activity. Thus, the preferential expression of stationary-phase genes by E[sigma]^38 is unlikely the consequence of selective inhibition of E[sigma]^70 by 6S RNA. |
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