The C. elegans sex determination protein MOG-3 functions in meiosis and binds to the CSL co-repressor CIR-1.

In the germ line of the Caenorhabditis elegans hermaphrodite, nuclei either proliferate through mitosis or initiate meiosis, finally differentiating as spermatids or oocytes. The production of oocytes requires repression of the fem-3 mRNA by cytoplasmic FBF and nuclear MOG proteins. Here we report the identification of the sex determining gene mog-3 and show that in addition to its role in gamete sex determination, it is necessary for meiosis by acting downstream of GLP-1/Notch.

Roles of the C. elegans cyclophilin-like protein MOG-6 in MEP-1 binding and germline fates.

The switch from spermatogenesis to oogenesis in the Caenorhabditis elegans hermaphrodite requires mog-6, which post-transcriptionally represses the fem-3 RNA. In this study, we show that mog-6 codes for a divergent nuclear cyclophilin, in that a conserved domain is not required for its function in the sperm-oocyte switch. MOG-6 binds to the nuclear zinc finger protein MEP-1 through two separate domains that are essential for the role of MOG-6 in the sperm-oocyte switch.

RNA and sex determination in Caenorhabditis elegans. Post-transcriptional regulation of the sex-determining tra-2 and fem-3 mRNAs in the Caenorhabditis elegans hermaphrodite.

The Caenorhabditis elegans hermaphrodite sequentially produces sperm and oocytes from a single pool of precursors. Therefore, the hermaphrodite's germ line is the site of two major cell fate decisions: a germ cell precursor first undergoes a mitosis/meiosis decision and then a sperm/oocyte decision. While the mitosis/meiosis decision is governed by Notch/GLP-1 signalling, the sperm/oocyte decision relies on post-transcriptional regulation of two key mRNAs, tra-2 and fem-3.