Fig. 5. Genetic pathways for germ cell apoptosis in C. elegans. (A) The genetic pathway for constitutive germ cell apoptosis. The genes lin-35, dpl-1, efl-2 and, most likely, efl-1, promote constitutive germ cell apoptosis by blocking the function of the anti-apoptotic gene ced-9 or by enhancing the function of the pro-apoptotic genes ced-4 and ced-3, respectively. Furthermore, a lin-35, dpl-1, efl-1 and efl-2-independent pathway most likely acts in parallel to lin-35, dpl-1, efl-1 and efl-2 to promote constitutive germ cell apoptosis. Solid lines represent confirmed genetic interactions. (B) The genetic pathway for DNA damage-induced germ cell apoptosis. lin-35, dpl-1 and efl-2 function downstream of or in parallel to cep-1 to cause DNA damage-induced germ cell apoptosis by controlling the expression of unknown target genes. See text for details.