HspR is a global negative regulator of heat shock gene expression in Deinococcus radiodurans

Summary The HspR protein functions as a negative regulator of chaperone and protease gene expression in a diversity of bacteria. Here we have identified, cloned and deleted the Deinococcus radiodurans HspR homologue, DR0934. ΔhspR mutants exhibit moderate growth defects when shifted to mild heat sho...

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Bibliographic Details
Published in:Molecular microbiology 2005-03, Vol.55 (5), p.1579-1590
Main Authors: Schmid, Amy K., Howell, Heather A., Battista, John R., Peterson, Scott N., Lidstrom, Mary E.
Format: Article
Language:English
Subjects:
5' Untranslated Regions
Bacterial Proteins - physiology
Bacteriology
Biological and medical sciences
Deinococcus - genetics
Deinococcus radiodurans
Fundamental and applied biological sciences. Psychology
Gene expression
Gene Expression Regulation, Bacterial
Heat-Shock Proteins - genetics
Heat-Shock Proteins - physiology
Microbiology
Miscellaneous
Molecular Chaperones - metabolism
Proteins
Repressor Proteins - physiology
Transcription, Genetic
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Summary:Summary The HspR protein functions as a negative regulator of chaperone and protease gene expression in a diversity of bacteria. Here we have identified, cloned and deleted the Deinococcus radiodurans HspR homologue, DR0934. ΔhspR mutants exhibit moderate growth defects when shifted to mild heat shock temperatures, but are severely impaired for survival at 48°C. Using quantitative reverse transcription polymerase chain reaction and global transcriptional analysis, we have identified 14 genes that are derepressed in the absence of stress in the ΔhspR background, 11 of which encode predicted chaperones and proteases, including dnaKJgrpE, ftsH, lonB, hsp20 and clpB. Promoter mapping indicated that the transcription of these genes initiates from a promoter bearing a σ70‐type consensus, and that putative HspR binding sites (HAIR) were present in the 5′‐untranslated regions. Electrophoretic mobility shift assays indicated that HspR binds to these promoters at the HAIR site in vitro. These results strongly suggest that DR0934 encodes the HspR‐like global negative regulator of D. radiodurans that directly represses chaperone and protease gene expression by binding to the HAIR site in close proximity to promoter regions.
ISSN:0950-382X
1365-2958
DOI:10.1111/j.1365-2958.2005.04494.x