A dominant negative 14-3-3 mutant in Schizosaccharomyces pombe distinguishes the binding proteins involved in sexual differentiation and check point.

The homothallic fission yeast Schizosaccharomyces pombe undergoes sexual differentiation when starved, but sam (skips the requirement of starvation for mating) mutants such as those carrying mutations in adenylate cyclase (cyr1) or protein kinase A (pka1) mate without starvation. Here, we identified sam3, a dominant negative allele of rad24, encoding one of two 14-3-3 proteins. Genetic mapping and whole-genome sequencing showed that the sam3 mutation comprises a change in nucleotide at position 959 from guanine to adenine, which switches the amino acid at position 185 from glutamic acid to lysine (E185K).