Fig. 5. Expression of constitutively active Foxo3a in mouse oocytes leads to significantly reduced oocyte size. Zp3-Foxo3a Tg mice, or their WT littermates, were sacrificed at PD8 and PD13, and oocyte diameters measured. The mean diameter of oocytes from type 3b follicles was 24.27±3.06 µm for WT mice (WT3b), and 19.47±3.14 µm for Tg mice (Tg3b). Mean oocyte diameter in type 4 follicles was 34.36±4.21 µm for WT mice (WT4) and 24.08±6.29 µm for Tg mice (Tg4). Different lowercase letters (a, b, c) indicate significant differences (P<0.001). For each genotype and each follicle type, 100 oocytes were measured from ovarian sections.