Fig. 3. Progesterone treatment of wild-type worms mimics phenotypes caused by cholesterol deprivation. (A,C) Normaski micrographs of wild-type worms grown on normal plates. (B,D) Normaski micrographs of representative wild-type worms cultured on low-sterol NGM plates containing 20 µg/ml progesterone. The phenotypes of Gen 1 adults are presented (see Materials and methods). (A) Normal gonadal cell migration. (B) Abnormal gonadal cell migration in animals cultured on progesterone plates. The distal tip cell migrated on the ventral side all the way up to the pharynx, failing to make either of the programmed turns. The black arrow indicates the direction of dtc migration. (C) Under normal conditions, the sperm (white arrowheads) are enclosed within spermatheca (sp). (D) Loose sperm in N2 animals cultured on progesterone plates. White arrowheads indicate sperm found within pseudocoelomic space, probably owing to rupture of the basement membrane surrounding the somatic gonad. Scale bars: 20 µm.