Regulation of sexual agglutinability in <italic>Saccharomyces cerevisiae</italic> of α and α types by sex-specific factors produced by their respective opposite mating types

Abstract

The sexual agglutinability of haploid cells of heterothallic Saccharomyces cerevisiae was repressed when they were cultured in the absence of easily fermentable sugars, such as glucose and mannose. The repression was reversed by the action of hormone-like substances of the opposite mating types. The substance produced by α mating type cells was identical to α subtsance-I which is known to induce sexual agglutinability of inducible α mating type cells. The α mating type cells produce a new hormone-like substance which induces or enhances sexual agglutinability of α mating type cells. A crude fraction of the α mating type-specific substance (α substance-I) was obtained by passing the culture filtrate of α mating type cells through Amberlite CG-50 (H+ form), followed by elution with 1.5 M ammonia.