The alpha 2 protein of S. cerevisiae, the product of the MAT alpha 2 gene, represses a set of cell-type-specific genes (the a-specific genes) by binding to an operator sequence upstream of each gene. We demonstrate that a second yeast regulatory protein, a1, the product of the MATa1 gene, can alter the binding specificity of alpha 2 so that it no longer recognizes the a-specific gene operator, but instead acquires the ability to recognize a different operator sequence found upstream of haploid-specific genes. Thus, under the influence of a1, alpha 2 can repress haploid-specific genes. An alpha cell expresses alpha 2 but not a1, so that alpha 2 turns off only the a-specific genes. An a/alpha cell makes both a1 and alpha 2, in a ratio that ensures that alpha 2 is distributed between two distinct binding modes: the alpha 2 binding mode and the a1-alpha 2 binding mode. Thus in an a/alpha cell, alpha 2 represses two distinct classes of genes.
|Evidence ID||Analyze ID||Interactor||Interactor Systematic Name||Interactor||Interactor Systematic Name||Type||Assay||Annotation||Action||Modification||Phenotype||Source||Reference||Note|
|Evidence ID||Analyze ID||Gene||Gene Systematic Name||Gene Ontology Term||Gene Ontology Term ID||Qualifier||Aspect||Method||Evidence||Source||Assigned On||Annotation Extension||Reference|
|Evidence ID||Analyze ID||Gene||Gene Systematic Name||Phenotype||Experiment Type||Experiment Type Category||Mutant Information||Strain Background||Chemical||Details||Reference|
|Evidence ID||Analyze ID||Regulator||Regulator Systematic Name||Target||Target Systematic Name||Experiment||Assay||Construct||Conditions||Strain Background||Reference|