Induction of sexual agglutinability of α mating-type cells as the primary action of the peptidyl sex factor from α mating-type cells in Saccharomyces cerevisiae

Abstract

The effect of a pure preparation of α substance-I_A (αS-I_A) whose amino acid sequence is identical to that of one of the α factor peptides (α2), on sexual agglutinability and DNA synthesis was comparatively studied. The optimum concentration of αS-I_A for the induction of sexual agglutinability of cells of an inducible α strain was 1 ng/ml. The inducing action of αS-I_A was detected in 20 min and reached a maximum in 60 min. Only 8.7% inhibition of DNA synthesis by αS-I_A in the same strain was detected in 1 hr and 40.4% inhibition in 2 hr at a concentration of 1 μg/ml. These results suggest that the primary action of the peptidyl α sex fractor on a mating-type cells is the induction of sexual agglutinabiity.