a/Alpha-specific repression by MAT alpha 2.
The product of the MAT alpha 2 gene is a DNA-binding protein that acts as a repressor of two different sets of cell type-specific genes. In alpha cells, the alpha 2 protein represses the transcription of several a-specific genes. In a/alpha cells, the alpha 2 protein acts together with the product of the MATa1 gene, the a1 protein, to repress several genes used by haploids in the mating process. In addition to the mat alpha 2 mutations that result in defects in both types of regulation, other mat alpha 2 alleles have been described that result in defects in the repression of a-specific genes but that do not affect the ability of the alpha 2 and a1 proteins to interact to repress the haploid-specific genes. We report here the isolation of a new class of mat alpha 2 mutations that do not affect the ability of the alpha 2 protein to repress a-specific genes, but that interfere with the ability of the alpha 2 protein to interact with the a1 protein to repress the haploid-specific genes and establish the a/alpha cell type. These mutations may help determine the means by which the a1 protein interacts with alpha 2 to expand the set of genes under its control.
Strathern
J
J
Laboratory of Eukaryotic Gene Expression, National Cancer Institute-Frederick Cancer Research Facility, Maryland 21701.
Shafer
B
B
Hicks
J
J
McGill
C
C
D000595:Amino Acid Sequence; D001483:Base Sequence; D004262:DNA Restriction Enzymes; D004268:DNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism; D005796:Genes; D005800:Genes, Fungal; D008969:Molecular Sequence Data; D009154:Mutation; D010957:Plasmids; D012097:Repressor Proteins / Q000235:genetics*; D012441:Saccharomyces cerevisiae / Q000235:genetics*; D014157:Transcription Factors / Q000235:genetics*
D004268:DNA-Binding Proteins; D012097:Repressor Proteins; D014157:Transcription Factors; D004262:DNA Restriction Enzymes