Fig. 7. Enhancement of oogenesis by physiological apoptosis. (A) Apoptosis facilitates progeny production in car-1(RNAi) and cpb-3(RNAi) hermaphrodites. Brood size was only modestly reduced by RNAi depletion of either car-1 or cpb-3 in the N2 background, but was dramatically decreased when RNAi was performed in ced-3(n717) animals. In this representative experiment, N2, n=10; cpb-3(RNAi), n=21; car-1(RNAi), n=19; ced-3, n=10; ced-3;cpb-3(RNAi), n=20; ced-3;cpb-3(RNAi), n=21. Among multiple experiments, the brood size of ced-3(n717) varied between 92% and 98% of wild type, always within the range of statistical insignificance. Importantly, in each experiment car-1 and cpb-3 RNAi resulted in consistent reductions in brood size in the wild-type and ced-3 backgrounds. Error bars represent one standard deviation; asterisks denote P<0.05 by t-test comparing the results of car-1 or cpb-3 RNAi depletion with either N2 or ced-3(n717) controls. (B-F) Nomarski images of ced-3 and RNAi hermaphrodites. (B) One-day-old ced-3(n717);car-1(RNAi) hermaphrodites accumulate abnormal oocytes at the proximal gonad end. DAPI staining (insert) reveals that these proximal oocytes are arrested in diakinesis. A white bar indicates the approximate region from which the DAPI image was obtained from a fixed whole animal. (C) A one-day-old ced-3(n717) hermaphrodite gonad, depicted as in B, is indistinguishable from wild type. (D) A four-day-old ced-3(n717) hermaphrodite gonad. Compared with in the gonad in C, the pachytene region extends further proximally. Note that only three oocytes are present. (E) One-day-old ced-3(n717);cpb-3(RNAi) hermaphrodite gonads have an extended pachytene region (see DAPI staining insert) and fewer oocytes than normal. (F) A three-day-old ced-3(n717);cpb-3(RNAi) hermaphrodite gonad. The extended pachytene region is maintained but abnormal oocytes accumulate proximally, many of which are in diakinesis (not shown). Oocytes are outlined by dashed lines in B,D-F.