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 Gross, C A Search for Related Content PubMed PubMed Citation Articles by Zhou, Y N Articles by Gross, C A

research-article

How a mutation in the gene encoding sigma 70 suppresses the defective heat shock response caused by a mutation in the gene encoding sigma 32.

Department of Bacteriology, University of Wisconsin, Madison 53706.

ABSTRACT

In Escherichia coli, transcription of the heat shock genes is regulated by sigma 32, the alternative sigma factor directing RNA polymerase to heat shock promoters. sigma 32, encoded by rpoH (htpR), is normally present in limiting amounts in cells. Upon temperature upshift, the amount of sigma 32 transiently increases, resulting in the transient increase in transcription of the heat shock genes known as the heat shock response. Strains carrying the rpoH165 nonsense mutation and supC(Ts), a temperature-sensitive suppressor tRNA, do not exhibit a heat shock response. This defect is suppressed by rpoD800, a mutation in the gene encoding sigma 70. We have determined the mechanism of suppression. In contrast to wild-type strains, the level of sigma 32 and the level of transcription of heat shock genes remain relatively constant in an rpoH165 rpoD800 strain after a temperature upshift. Instead, the heat shock response in this strain results from an approximately fivefold decrease in the cellular transcription carried out by the RNA polymerase holoenzyme containing mutant RpoD800 sigma 70 coupled with an overall increase in the translational efficiency of all mRNA species.

This article has been cited by other articles:

• Grigorova, I. L., Phleger, N. J., Mutalik, V. K., Gross, C. A. (2006). Insights into transcriptional regulation and {sigma} competition from an equilibrium model of RNA polymerase binding to DNA. Proc. Natl. Acad. Sci. USA 103: 5332-5337 [Abstract] [Full Text]  
• King, T., Seeto, S., Ferenci, T. (2006). Genotype-by-Environment Interactions Influencing the Emergence of rpoS Mutations in Escherichia coli Populations. Genetics 172: 2071-2079 [Abstract] [Full Text]  
• Mooney, R. A., Landick, R. (2003). Tethering {sigma}70 to RNA polymerase reveals high in vivo activity of {sigma} factors and {sigma}70-dependent pausing at promoter-distal locations. Genes Dev. 17: 2839-2851 [Abstract] [Full Text]  
• Maeda, H., Fujita, N., Ishihama, A. (2000). Competition among seven Escherichia coli {sigma} subunits: relative binding affinities to the core RNA polymerase. Nucleic Acids Res 28: 3497-3503 [Abstract] [Full Text]  
• Sharp, M. M., Chan, C. L., Lu, C. Z., Marr, M. T., Nechaev, S., Merritt, E. W., Severinov, K., Roberts, J. W., Gross, C. A. (1999). The interface of sigma with core RNA polymerase is extensive, conserved, and functionally specialized. Genes Dev. 13: 3015-3026 [Abstract] [Full Text]  
• Arthur, T. M., Burgess, R. R. (1998). Localization of a sigma 70 Binding Site on the N Terminus of the Escherichia coli RNA Polymerase beta ' Subunit. J. Biol. Chem. 273: 31381-31387 [Abstract] [Full Text]