Figure 1.

(A) Schematic of C. elegans adult germline. The stem and progenitor cell region resides at the distal end followed by the transition zone where cells switch from mitosis to meiosis. Next is the pachytene region where germ cells undergo meiosis and the oocytes are located at the proximal end. (B) The regulatory network that controls the decision between stem cell proliferation and differentiation (mitotic and meiotic cell cycles). GLP-1/Notch signaling activated by a somatic distal tip cell (yellow) promotes mitotic divisions in the stem cell region of the worm germline (blue). FBF-1 and FBF-2 proteins bind and repress mRNAs that would initiate meiosis or differentiation. The GLD-1/NOS-3 and GLD-2/3 pathways promote entry into meiosis (maroon). We hypothesize that DLC-1 (green) promotes GLD-1 function.