This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Reprints and Permissions Copyright Information Books from ASM Press MicrobeWorld Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Zhou, Y. N. Articles by Jin, D. J. Search for Related Content PubMed PubMed Citation Articles by Zhou, Y. N. Articles by Jin, D. J.

 Previous Article  |  Next Article 

J. Bacteriol., Jul 1997, 4292-4298, Vol 179, No. 13
Copyright © 1997, American Society for Microbiology

RNA polymerase beta mutations have reduced sigma70 synthesis leading to a hyper-temperature-sensitive phenotype of a sigma70 mutant

YN Zhou and DJ Jin
Laboratory of Molecular Biology, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892, USA.

This work describes a mutational analysis of the interaction between the beta and sigma subunits of Escherichia coli RNA polymerase. The rpoD800 mutant has a temperature-sensitive growth phenotype because the mutant sigma70 polypeptide is not stable at a high temperature. Some rpoB mutations, including rpoB114, enhanced the temperature sensitivity of the rpoD800 mutant. We determined the mechanism by which the rpoB114 rpoD800 double mutant becomes hyper-temperature sensitive for growth. We found that the levels of the mutant sigma70 in the rpoB114 rpoD800 mutant were dramatically reduced compared to that in the rpoD800 mutant after temperature shift-up. The rate of synthesis of the sigma70 polypeptide was reduced in the rpoB114 rpoD800 double mutant compared to the rpoD800 mutant, whereas the half-life of the mutant sigma70 polypeptide after temperature shift-up was the same in both strains. We conclude that because of the reduction of expression of rpoD800 by rpoB114, in concert with the intrinsic instability of the mutant sigma70 polypeptide, the amount of holoenzyme containing sigma70 becomes limiting upon temperature shift-up. This results in the hyper- temperature sensitivity of the rpoB114 rpoD800 double mutant. Furthermore, the effect of rpoB114 on the expression of sigma70 is independent of the rpoD800 allele and is at the transcriptional level. In vitro transcription assays showed that the mutant RNA polymerase RpoB114 was defective in transcribing the two major promoters of the rpoD operon specifically. The effects of these rpoB mutations on gene expression are discussed.

This article has been cited by other articles:

• Cabrera, J. E., Cagliero, C., Quan, S., Squires, C. L., Jin, D. J. (2009). Active Transcription of rRNA Operons Condenses the Nucleoid in Escherichia coli: Examining the Effect of Transcription on Nucleoid Structure in the Absence of Transertion. J. Bacteriol. 191: 4180-4185 [Abstract] [Full Text]  
• Roberts, J. W. (2009). Promoter-specific control of E. coli RNA polymerase by ppGpp and a general transcription factor. Genes Dev. 23: 143-146 [Abstract] [Full Text]  
• Durfee, T., Hansen, A.-M., Zhi, H., Blattner, F. R., Jin, D. J. (2008). Transcription Profiling of the Stringent Response in Escherichia coli. J. Bacteriol. 190: 1084-1096 [Abstract] [Full Text]  
• Zhi, H., Wang, X., Cabrera, J. E., Johnson, R. C., Jin, D. J. (2003). Fis Stabilizes the Interaction between RNA Polymerase and the Ribosomal Promoter rrnB P1, Leading to Transcriptional Activation. J. Biol. Chem. 278: 47340-47349 [Abstract] [Full Text]  
• Magnusson, L. U., Nystrom, T., Farewell, A. (2003). Underproduction of sigma 70 Mimics a Stringent Response. A PROTEOME APPROACH. J. Biol. Chem. 278: 968-973 [Abstract] [Full Text]  
• Myers, J. M., Myers, C. R. (2000). Role of the Tetraheme Cytochrome CymA in Anaerobic Electron Transport in Cells of Shewanella putrefaciens MR-1 with Normal Levels of Menaquinone. J. Bacteriol. 182: 67-75 [Abstract] [Full Text]  
• Zhou, Y. N., Jin, D. J. (1998). The rpoB mutants destabilizing initiation complexes at stringently controlled promoters behave like "stringent" RNA polymerases in Escherichia coli. Proc. Natl. Acad. Sci. USA 95: 2908-2913 [Abstract] [Full Text]