Fig. 5. Ovary and oocyte morphology in adult wild-type (WT) and N-Zfp36l2 mutant females. (A,B) Secondary follicles in which the small oocytes are surrounded by cuboidal cells. (C,D) Tertiary follicles are shown in which the cuboidal cells have divided actively, forming a stratified layer around the oocyte. Irregular spaces have appeared, forming the follicular antrum. (E,F) Graafian follicles, in which the large follicular cavity is distended with fluid, and the cumulus oophorus contains a mature oocyte surrounded by a thick zona pelucida and well-formed corona radiata. (G,H) The corpora lutea, which appear to form normally after ovulation. Scale bars: 40 µm in A-D; 100 µm in E-H.