HSP-CBF is an NF-Y-dependent Coactivator of the Heat Shock Promoters CCAAT Boxes

Carol Imbriano, Fabrizio Bolognese, Aymone Gurtner, Giulia Piaggio, Roberto Mantovani

Research output: Contribution to journalArticlepeer-review

Abstract

The cellular response to toxic stimuli is elicited through the expression of heat shock proteins, a transcriptional process that relies upon conserved DNA elements in the promoters: the Heat Shock Elements, activated by the heat shock factors, and the CCAAT boxes. The identity of the CCAAT activator(s) is unclear because two distinct entities, NF-Y and HSP-CBF, have been implicated in the HSP70 system. The former is a conserved ubiquitous trimer containing histone-like subunits, the latter a 110-kDa protein with an acidic N-terminal. We analyzed two CCAAT-containing promoters, HSP70 and HSP40, with recombinant NF-Y and HSP-CBF using electrophoretic mobility shift assay, protein-protein interactions, transfections and chromatin immunoprecipitation assays (ChIP) assays. Both recognize a common DNA-binding protein in nuclear extracts, identified in vitro and in vivo as NF-Y. Both CCAAT boxes show high affinity for recombinant NF-Y but not for HSP-CBF. However, HSP-CBF does activate HSP70 and HSP40 transcription under basal and heat shocked conditions; for doing so, it requires an intact NF-Y trimer as judged by cotransfections with a diagnostic NF-YA dominant negative vector. HSP-CBF interacts in solution and on DNA with the NF-Y trimer through an evolutionary conserved region. In yeast two-hybrid assays HSP-CBF interacts with NF-YB. These data implicate HSP-CBF as a non-DNA binding coactivator of heat shock genes that act on a DNA-bound NF-Y.

Original languageEnglish
Pages (from-to)26332-26339
Number of pages8
JournalJournal of Biological Chemistry
Volume276
Issue number28
DOIs
Publication statusPublished - Jul 13 2001

ASJC Scopus subject areas

  • Biochemistry

Fingerprint Dive into the research topics of 'HSP-CBF is an NF-Y-dependent Coactivator of the Heat Shock Promoters CCAAT Boxes'. Together they form a unique fingerprint.

Cite this