Ssn6-Tup1 is a general repressor of transcription in yeast.
The homeodomain protein alpha 2 and the SRF-like protein Mcm1 are required to establish cell type in the yeast Saccharomyces cerevisiae. Together, these regulatory proteins recognize a specific DNA operator, marking a set of genes for transcriptional repression. In this paper, we show that occupancy of the operator by alpha 2-Mcm1 is not sufficient to bring about repression. Rather, repression is effected only when Ssn6 (a TPR protein) and Tup1 (a beta-transducin repeat protein) are also present in the cell. We show that Ssn6 represses transcription when brought to a promoter by a bacterial DNA-binding domain and that Tup1 is required for this repression. Based on these and other results, we propose that Ssn6-Tup1 is a general repressor of transcription in yeast, recruited to target promoters by a variety of sequence-specific DNA-binding proteins.
Keleher
C A
CA
Department of Biochemistry and Biophysics, University of California, San Francisco 94143.
Redd
M J
MJ
Schultz
J
J
Carlson
M
M
Johnson
A D
AD
D015151:Immunoblotting; D008957:Models, Genetic; D010957:Plasmids; D012097:Repressor Proteins / Q000235:genetics*; D012441:Saccharomyces cerevisiae / Q000235:genetics*; D014158:Transcription, Genetic
D012097:Repressor Proteins