Negative regulation of the heat shock response in Streptomyces

Citation
P. Servant et P. Mazodier, Negative regulation of the heat shock response in Streptomyces, ARCH MICROB, 176(4), 2001, pp. 237-242
Citations number
38
Language
INGLESE
art.tipo
Review
Categorie Soggetti
Microbiology
Journal title
ARCHIVES OF MICROBIOLOGY
ISSN journal
0302-8933 → ACNP
Volume
176
Issue
4
Year of publication
2001
Pages
237 - 242
Database
ISI
SICI code
0302-8933(200110)176:4<237:NROTHS>2.0.ZU;2-9
Abstract
All organisms respond to a sudden increase in temperature by inducing the s ynthesis of a set of proteins called heat shock proteins (HSPs). Although t he induction of HSPs is a universal response, a diversity of mechanisms con trol HSP synthesis in different organisms. In Streptomyces, the synthesis o f major HSPs, such as the widespread molecular chaperones DnaK, ClpB, GroEL and HSP18, is negatively controlled at the transcriptional level by at lea st three different repressors. The control of groE gene expression involves an inverted repeat (called the CIRCE element) that is highly conserved amo ng eubacteria, and the HrcA repressor. The dnaK operon and clpB belong to t he HspR /HAIR regulon. The HspR repressor-HAIR operator system is used in s ome bacteria but is not widespread. In particular, it has not been found in gram-positive bacteria with low G+C content. Transcription of hsp18, which encodes a small HSP, is regulated by the RheA repressor. This repressor, w hich has intrinsic thermosensor activity, has to date been identified only in Streptomyces.