Figure 2.

Signal transduction pathways that regulate the initiation of meiosis in fission yeast. Four pathways that regulate expression of the ste11 gene, which encodes a transcription factor crucial for sexual development, are schematically depicted. From left to right: The cAMP pathway response to glucose; the TORC1 pathway response to nitrogen sources; the MAP kinase pathway response to mating pheromones; and the MAP kinase pathway response to environmental stresses. The former two pathways down-regulate, whereas the latter two up-regulate, ste11 expression. Reproduced from Ref. 25 with some modifications.