Transcriptional repression directed by the yeast alpha 2 protein in vitro.
The alpha 2 protein, a homeodomain protein involved in specifying cell type in the budding yeast Saccharomyces cerevisiae, is a transcriptional repressor. alpha 2 binds cooperatively with Mcm1, a serum response factor-related protein, to the a-specific gene operator. The alpha 2-Mcm1 complex in turn recruits Ssn6 and Tup1 to the operator, and we believe that these latter two proteins are responsible for the transcriptional repression. Placement of the a-specific gene operator in any of a variety of positions upstream of a test promoter leads to repression of that promoter in vivo. In this respect, the a-specific gene operator resembles a negatively acting enhancer. Here we describe the in vitro reconstitution of this example of negative control from a distance. We observe repression in vitro in the absence of exogenously added activator protein and on templates that lack binding sites for known activator proteins, and we infer that alpha 2-directed repression acts on the general transcription machinery.
Herschbach
B M
BM
Department of Biochemistry and Biophysics, University of California, San Francisco 94143-448.
Arnaud
M B
MB
Johnson
A D
AD
D004268:DNA-Binding Proteins / Q000378:metabolism*; D004926:Escherichia coli; D005656:Fungal Proteins / Q000378:metabolism*; D018398:Homeodomain Proteins; D009687:Nuclear Proteins; D009875:Operator Regions, Genetic; D017354:Point Mutation; D011994:Recombinant Proteins; D012097:Repressor Proteins / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins; D013698:Templates, Genetic; D014158:Transcription, Genetic
C065455:CYC8 protein, S cerevisiae; D004268:DNA-Binding Proteins; D005656:Fungal Proteins; D018398:Homeodomain Proteins; C062928:MATA2 protein, S cerevisiae; D009687:Nuclear Proteins; D011994:Recombinant Proteins; D012097:Repressor Proteins; D029701:Saccharomyces cerevisiae Proteins; C066502:TUP1 protein, S cerevisiae