Cryptosporidium follows an intrinsic developmental program where it counts down to obligate sexual reproduction. The parasite propagates asexually for three consecutive 12-hour cycles before transitioning to male and female gamete development in the fourth cycle. We discovered that transcription factor Myb-M is a master regulator of Cryptosporidium male fate and is both necessary and sufficient to drive male gametogenesis (Walzer et al., Nature, 2024). But how Myb-M initiates the male developmental program remains unknown. Our lab is currently investigating the targets and binding partners of Myb-M and other male-specific transcription factors.

Our single-cell analyses revealed the male-specific expression of three putative RNA-binding proteins (RBPs) in early-, mid-, and late-stage Cryptosporidium males. We denote these genes as RBP-M1, RBP-M2, and RBP-M3. Interestingly, the transcriptional profile of RBP-M1 closely matches Myb-M, suggesting it is a co-regulator of male fate determination. Our lab is currently investigating how RBP-M1 regulates male fate transcripts, including Myb-M, and reinforces a positive feedback loop for male differentiation. While our initial focus is on RBP-M1, our next experiments will examine the roles of RBP-M2 and RBP-M3 in male transcriptional stability and translational control.