A ste12 allele having a differential effect on a versus alpha cells

Area of Science:

• Molecular Biology
• Yeast Genetics
• Cellular Signaling

Background:

• The transcriptional activator Ste12p is crucial for yeast pheromone response, regulating mating and cell fusion.
• Ste12p activity depends on protein-protein interactions to activate specific gene sets (non-cell-type, a-specific, and alpha-specific).

Purpose of the Study:

• To isolate and characterize a novel ste12 allele affecting alpha-specific gene activation.
• To investigate the role of Ste12p in determining cell-type-specific gene expression during mating.

Main Methods:

• Isolation and characterization of a partially functional ste12 allele (ste12-T50).
• Genetic analysis using yeast mating assays, specifically in mat alpha 2 mutant cells.
• Phenotypic analysis of the ste12-T50 mutation's effect on mating behavior.

Main Results:

• A partially functional ste12 allele, ste12-T50, was identified, which is specifically defective in activating alpha-specific genes.
• In mat alpha 2 mutant cells, ste12-T50 shifts gene expression balance towards a-specific genes, resulting in an a mating phenotype.
• Additional ste12 mutants conferring an a mating phenotype on mat alpha 2 cells were also isolated.

Conclusions:

• The ste12-T50 mutation selectively impairs alpha-specific gene activation, highlighting Ste12p's differential roles in gene regulation.
• This study provides insights into the complex protein-protein interactions governing cell-type-specific gene expression in yeast mating pathways.
• The findings contribute to understanding the genetic control of mating behavior and cell-type determination in Saccharomyces cerevisiae.