MOLECULAR-CLONING OF THE DAC2/FUS3 GENE ESSENTIAL FOR PHEROMONE-INDUCED G1-ARREST OF THE CELL-CYCLE IN SACCHAROMYCES-CEREVISIAE

Mating pheromones, known as a and α-factors, arrest the division of cells of opposite mating types, α and a respectively, in Saccharomyces cerevisiae. I have cloned the DAC2 gene, which is required for both pheromone-induced division-arrest and cell-fusion during conjugation. The constructed dac2::LEU2 null mutation leads to defects in both pheromone-induced divisionarrest and cell-fusion during conjugation; it also suppresses the growth defect caused by the gpal mutation (a mutation in the α subunit of the S. cerevisiae G protein). These results indicate that DAC2 may be the same gene as FUS3, which was recently isolated by Elion et al. (1990) as a gene essential for cell-fusion during conjugation. The dac2::LEU2 null mutant also showed morphological alterations in response to mating pheromones. I show here that the DAC2 product plays an essential role in both the division-arrest signalling pathway of the yeast pheromone response and in cell-fusion during conjugation. © 1990 Springer-Verlag.