LARP-1 promotes oogenesis by repressing fem-3 in the C. elegans germline.
LA-related protein 1 (LARP-1) belongs to an RNA-binding protein family containing a LA motif. Here, we identify LARP-1 as a regulator of sex determination. In C. elegans hermaphrodites, a complex regulatory network regulates the switch from sperm to oocyte production. We find that simultaneous depletion of larp-1 and the Nanos homologue nos-3 results in germline masculinization. This phenotype is accompanied by a strong reduction of the levels of TRA-1, a GLI-family transcription factor that promotes oogenesis. TRA-1 levels are regulated by CBC(FEM-1), a ubiquitin ligase consisting of the FEM proteins, FEM-1, FEM-2 and FEM-3 and the cullin CUL-2. We show that both the masculinization phenotype and the reduction of TRA-1 levels observed in nos-3;larp-1 mutants require fem-3 activity, suggesting that nos-3 and larp-1 regulate the sperm-oocyte switch by inhibiting the fem genes. Consistently, fem-3 mRNA levels are increased in larp-1 mutants. By contrast, levels of fem-3 mRNA are not affected in nos-3 mutants. Therefore, our data indicate that LARP-1 and NOS-3 promote oogenesis by regulating fem-3 expression through distinct mechanisms.
Zanin
Esther
E
ETH Zurich, Institute of Biochemistry, Zurich, Switzerland.
Pacquelet
Anne
A
Scheckel
Claudia
C
Ciosk
Rafal
R
Gotta
Monica
M
D000818:Animals; D017173:Caenorhabditis elegans / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D029742:Caenorhabditis elegans Proteins / Q000235:genetics / Q000378:metabolism*; D005260:Female; D020935:MAP Kinase Signaling System; D008297:Male; D019950:Mitogen-Activated Protein Kinase 1 / Q000235:genetics / Q000378:metabolism; D009154:Mutation; D009865:Oocytes / Q000502:physiology; D009866:Oogenesis / Q000235:genetics / Q000502:physiology*; D010802:Phylogeny; D016601:RNA-Binding Proteins / Q000378:metabolism*; D019849:Sex Determination Processes / Q000502:physiology*; D013094:Spermatozoa / Q000502:physiology
D029742:Caenorhabditis elegans Proteins; C529876:LARP-1 protein, C elegans; D016601:RNA-Binding Proteins; C075059:fem-3 protein, C elegans; D019950:Mitogen-Activated Protein Kinase 1; C085697:mpk-1 protein, C elegans