Cellular differentiation is controlled largely by specific gene expression programs. In the fission yeast Schizosaccharomyces pombe, the high mobility group (HMG) protein Ste11 is the main transcription factor responsible for the switch from cellular proliferation to sexual differentiation (Sugimoto et al., 1991; Mata and Bähler, 2006). Ste11 activates many genes that are required for the initiation of sexual differentiation, including the mating-type genes and mei2, the latter of which encodes a master regulator of meiosis. Expression of ste11 is under the control of several signaling pathways, which respond to external factors, such as nutrition, stresses and mating pheromones. They include the cyclic adenosine monophosphate (cAMP) pathway, the target of rapamycin (TOR) complex 1 (TORC1) pathway and the two mitogen-activated protein kinase (MAPK) pathways (Yamamoto et al., 1997; Otsubo and Yamamoto, 2010). Recently, it has become apparent that phosphorylation of the C-terminal domain (CTD) of RNA polymerase II (Pol II) by CTD kinase I (Ctdk1) specifically affects the expression of ste11 (Coudreuse et al., 2010; Sukegawa et al., 2011). It has also been shown that the meiotic regulator Mei2, the expression of which is governed by Ste11, enhances expression of ste11 through a positivefeedback loop (Sukegawa et al., 2011). These new discoveries, together with previous findings, illustrate that a number of signal transduction pathways orchestrate the regulation of ste11 expression in response to intricate environmental changes. In this Cell Science at a Glance article, we summarize the current knowledge of these signaling pathways, and in the accompanying poster we present a comprehensive scheme showing the regulation of ste11 expression.