Open AccessThe Saccharomyces cerevisiae Hap5p Homolog from Fission Yeast Reveals Two Conserved Domains That Are Essential for Assembly of Heterotetrameric CCAAT-Binding Factor
Author(s) -
David S. McNabb,
Kuo-Yun Tseng,
Leonard Guarente
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.17.12.7008
Subject(s) - schizosaccharomyces pombe , biology , schizosaccharomyces , heterotetramer , transcription factor , caat box , saccharomyces cerevisiae , conserved sequence , promoter , binding site , genetics , microbiology and biotechnology , gene , protein subunit , peptide sequence , gene expression
The CCAAT-binding factor is an evolutionarily conserved heteromeric transcription factor that binds to CCAAT box-containing upstream activation sites within the promoters of numerous eukaryotic genes. The CCAAT-binding factor from Saccharomyces cerevisiae is a heterotetramer that contains the subunits Hap2p, Hap3p, Hap4p, and Hap5p and that functions in the activation of genes involved in respiratory metabolism. Here we describe the isolation of the cDNA encoding the Schizosaccharomyces pombe homolog of Hap5p, designated php5+. We have shown that Php5p is a subunit of the CCAAT-binding factor in fission yeast and is required for transcription of the S. pombe cyc1+ gene. Analysis of the evolutionarily conserved regions of Hap5p, Php5p, and the mammalian homolog CBF-C revealed two essential domains within Hap5p that are required for DNA binding and transcriptional activation. One is an 87-amino-acid core domain that is conserved among Hap5p, Php5p, and CBF-C and that is required for the assembly of the Hap2p-Hap3p-Hap5p heterotrimer both in vitro and in vivo. A second domain that is essential for the recruitment of Hap4p into the CCAAT-binding complex was identified in Hap5p and Php5p.