MCB
Home Help [Feedback] [For Subscribers] [Archive] [Search] [Contents]
This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrowReprints and Permissions
Right arrow Copyright Information
Right arrow Books from ASM Press
Right arrow MicrobeWorld
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Farkas, T.
Right arrow Articles by Zimarino, V.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Farkas, T.
Right arrow Articles by Zimarino, V.

Mol Cell Biol, February 1998, p. 906-918, Vol. 18, No. 2
0270-7306/98/$04.00+0
Copyright © 1998, American Society for Microbiology. All rights reserved.

Intramolecular Repression of Mouse Heat Shock Factor 1

Thomas Farkas, Yulia A. Kutskova, and Vincenzo Zimarino*

Biological and Technological Research Department (DIBIT), San Raffaele Scientific Institute, Milan, Italy

Received 16 October 1997/Accepted 13 November 1997

The pathway leading to transcriptional activation of heat shock genes involves a step of heat shock factor 1 (HSF1) trimerization required for high-affinity binding of this activator protein to heat shock elements (HSEs) in the promoters. Previous studies have shown that in vivo the trimerization is negatively regulated at physiological temperatures by a mechanism that requires multiple hydrophobic heptad repeats (HRs) which may form a coiled coil in the monomer. To investigate the minimal requirements for negative regulation, in this work we have examined mouse HSF1 translated in rabbit reticulocyte lysate or extracted from Escherichia coli after limited expression. We show that under these conditions HSF1 behaves as a monomer which can be induced by increases in temperature to form active HSE-binding trimers and that mutations of either HR region cause activation in both systems. Furthermore, temperature elevations and acidic buffers activate purified HSF1, and mild proteolysis excises fragments which form HSE-binding oligomers. These results suggest that oligomerization can be repressed in the monomer, as previously proposed, and that repression can be relieved in the apparent absence of regulatory proteins. An intramolecular mechanism may be central for the regulation of this transcription factor in mammalian cells, although not necessarily sufficient.

* Corresponding author. Mailing address: Biological and Technological Research Department (DIBIT), San Raffaele Scientific Institute, Room 4-A2-46, Via Olgettina 58, 20132 Milan, Italy. Phone: (39) 2 26 43 48 96. Fax: (39) 2 26 43 48 44. E-mail: zimarie{at}dibit.hsr.it.




This article has been cited by other articles:



Home Help [Feedback] [For Subscribers] [Archive] [Search] [Contents]
J. Bacteriol. J. Virol. Eukaryot. Cell
Microbiol. Mol. Biol. Rev. Clin. Vaccine Immunol. All ASM Journals

Copyright © 1998 by the American Society for Microbiology. All rights reserved.