Open AccessHir1p and Hir2p Function as Transcriptional Corepressors To Regulate Histone Gene Transcription in the Saccharomyces cerevisiae Cell Cycle
Author(s) -
Mona S. Spector,
Amanda Raff,
Heshani DeSilva,
Kenneth Lee,
Mary Ann Osley
Publication year - 1997
Publication title -
molecular and cellular biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.14
H-Index - 327
eISSN - 1067-8824
pISSN - 0270-7306
DOI - 10.1128/mcb.17.2.545
Subject(s) - biology , corepressor , transcription (linguistics) , promoter , transcriptional regulation , transcription coregulator , general transcription factor , saccharomyces cerevisiae , transcription factor , histone , histone methylation , genetics , microbiology and biotechnology , repressor , gene , gene expression , dna methylation , linguistics , philosophy
The HIR/HPC (histone regulation/histone periodic control) negative regulators play important roles in the transcription of six of the eight core histone genes during the Saccharomyces cerevisiae cell cycle. The phenotypes of hir1 and hir2 mutants suggested that the wild-type HIR1 and HIR2 genes encode transcriptional repressors that function in the absence of direct DNA binding. When Hir1p and Hir2p were artificially tethered to yeast promoters, each protein repressed transcription, suggesting that they represent a new class of transcriptional corepressors. The two proteins might function as a complex in vivo: Hir2p required both Hir1p and another Hir protein, Hir3p, to repress transcription when it was tethered to an HTA1-lacZ reporter gene, and Hir1p and Hir2p could be coimmunoprecipitated from yeast cell extracts. Tethered Hir1p also directed the periodic transcription of the HTA1 gene and repressed HTA1 transcription in response to two cell cycle regulatory signals. Thus, it represents the first example of a transcriptional corepressor with a direct role in cell cycle-regulated transcription.