Streptomyces A-Factor is a microbial hormone found in Streptomyces griseus. A-factor triggers streptomycin biosynthesis and cell differentiation by binding a repressor-type receptor protein (ArpA) and dissociating it from DNA.
The alpha factor pheromone arrests yeast in the G1 phase of their cell cycle. Alpha Factor Mating Pheromone induces the expression of mating genes, changes in nuclear architecture, and polarzes growth toward the mating partner.