Pheromonal Regulation of Development in Saccharomyces cerevisiae

Abstract

INTRODUCTION
Mating of the two different haploid cell types of baker’s yeast Saccharomyces cerevisiae to form a diploid provides a relatively simple system for studying the biochemical basis of intercellular signaling and developmental control in eukaryotic cells. Conjugation occurs efficiently when cultures of opposite mating type are mixed but only exceedingly rarely when cultures of the same haploid cell type are mixed. Thus, there must be specific biochemical features that distinguish and define the mating type of a yeast cell and that mediate the intercellular interactions occurring between them to permit conjugation. Indeed, substantial progress has been made over the last 10 years in describing events in the mating process at the molecular level (for reviews, see Crandall 1977for reviews, see Crandall 1978; Crandall et al. 1977; Manney and Meade 1977; MacKay 1978; Goodenough 1980; Thorner 1980; Manney et al. 1981). One exciting outcome of these investigations is the demonstration that reciprocal exchange of diffusible oligopeptide pheromones is the intercellular stimulus that initiates the physiological changes in haploid cells that culminate in mating. In this paper, mating will be discussed in light of recent advances in our understanding of the cellular and molecular biology of yeast. Where possible, the identification and biochemical mode of action of cell-type-specific gene products that function in this developmental process will be emphasized, particularly the pivotal role of the mating pheromones.

AN OVERVIEW OF MATING EVENTS
A diagrammatic representation of the conjugation process is shown in Figure 1 and is based on the observations of a large number...