MAT alpha 1 protein, a yeast transcription activator, binds synergistically with a second protein to a set of cell-type-specific genes.
We show by electrophoresis mobility shift and by DNAase I footprinting assays that the alpha 1 product of the yeast alpha mating-type locus binds to homologous sequences within the control regions of the three known alpha-specific genes. Binding requires both alpha 1 and a second yeast protein(s) (called PRTF) that is present in all three cell types (a, alpha, and a/alpha); neither protein binds alone. Binding and competition experiments using synthetic oligonucleotides indicate that PRTF binds to only part of the homology found at alpha-specific genes and imply that alpha 1 binds to the remainder. Our results suggest that alpha 1 renders gene expression alpha-specific by creating a binding site for PRTF. Similar experiments lead to the idea that PRTF also plays a role in transcription of a-specific genes. Perhaps a-specificity is achieved through the occlusion of the PRTF binding site by alpha 2, the negative regulator encoded by the alpha mating-type locus.
Bender
A
A
Sprague
G F
GF
D001483:Base Sequence; D001665:Binding Sites; D001667:Binding, Competitive; D004271:DNA, Fungal / Q000378:metabolism*; D004274:DNA, Recombinant; D003850:Deoxyribonuclease I / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D004926:Escherichia coli / Q000235:genetics; D005656:Fungal Proteins / Q000378:metabolism*; D005786:Gene Expression Regulation; D000072235:Mating Factor; D010455:Peptides / Q000235:genetics / Q000378:metabolism*; D010957:Plasmids; D012441:Saccharomyces cerevisiae / Q000235:genetics*; D014158:Transcription, Genetic
D004271:DNA, Fungal; D004274:DNA, Recombinant; D005656:Fungal Proteins; D010455:Peptides; D000072235:Mating Factor; D003850:Deoxyribonuclease I