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

Mol Gen Genet. 1995 Jan 6;246(1):80-90. doi: 10.1007/BF00290136.

Abstract

The transcriptional activator Ste12p is a key component of the yeast pheromone response pathway: phosphorylated as a consequence of signal transduction, it activates transcription of genes that promote mating and the subsequent fusion of the two cell types a and alpha. Activation by Ste12p requires three types of protein-protein interaction between DNA-binding activator proteins: (1) Ste12p by itself can induce non-cell-type-specific genes involved in mating; (2) cooperation of the transactivator Mcm1p with Ste12p induces a-specific genes; and (3) formation of a complex of the activator proteins Mcm1p and alpha 1 (a transcriptional activator of alpha-specific genes) with Ste12p is believed to induce alpha-specific genes. We isolated and characterized a partially functional ste12 allele (ste12-T50), that is defective only in the activation of alpha-specific genes. ste12-T50 was isolated as a second-site mutation conferring the a mating phenotype on mat alpha 2 mutant cells. In mat alpha 2 cells, where due to the lack of repressor, alpha 2, both sets of cell-type-specific genes are expressed, ste12-T50 apparently tips the balance in favor of a-specific gene expression. Thus, mat alpha 2 ste12-T50 cells mate like a cells. Additional ste12 mutants that confer the a mating phenotype on mat alpha 2 cells have also been isolated.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Alleles
  • Cell Line
  • DNA-Binding Proteins / genetics
  • DNA-Binding Proteins / metabolism
  • Fungal Proteins / genetics*
  • Fungal Proteins / metabolism
  • Gene Expression Regulation, Fungal*
  • Genes, Fungal*
  • Minichromosome Maintenance 1 Protein
  • Phenotype
  • Point Mutation*
  • Saccharomyces cerevisiae / genetics
  • Saccharomyces cerevisiae / physiology
  • Saccharomyces cerevisiae Proteins*
  • Sex Attractants / biosynthesis
  • Sex Attractants / genetics
  • Trans-Activators / metabolism
  • Transcription Factors / genetics*
  • Transcription Factors / metabolism

Substances

  • DNA-Binding Proteins
  • Fungal Proteins
  • Minichromosome Maintenance 1 Protein
  • STE12 protein, S cerevisiae
  • Saccharomyces cerevisiae Proteins
  • Sex Attractants
  • Trans-Activators
  • Transcription Factors