Regulation of sexual differentiation initiation in Schizosaccharomyces pombe.

The fission yeast Schizosaccharomyces pombe is an excellent model organism to explore cellular events owing to rich tools in genetics, molecular biology, cellular biology, and biochemistry. S. pombe proliferates continuously when nutrients are abundant, but arrests in G1 phase upon depletion of nutrients such as nitrogen and glucose. When cells of opposite mating types are present, cells conjugate, fuse, undergo meiosis, and finally form four spores. This sexual differentiation process in S. pombe has been studied extensively. To execute sexual differentiation, the glucose-sensing cAMP-PKA pathway, nitrogen-sensing TOR and SAPK pathways are crucial, and the MAPK cascade is essential for pheromone sensing. These signals regulate ste11 at the transcriptional and translational levels, and Ste11 is modified in multiple ways. This review summarizes the initiation of sexual differentiation in S. pombe based on results I have helped to obtain including the work of many excellent researchers.