Figure 3

Germ-cell nests persisted in Amhr2-Cre/+;Notch2^flox/- mice. (A, B) Germ-cell nests in (A) littermate control and (B) 8-day-old Amhr2-Cre/+;Notch2^flox/- mouse. (B) In the mutant mouse, the germ-cell nests were still visible (black arrows), whereas in (A) the nests had broken down and the oocytes were assembled into primordial follicles. Slides were stained using the Periodic-Acid-Schiff (PAS) (C) By postnatal day (PND)3, most oocytes expressing the cytoplasmic germ-cell marker Vasa (orange) in the cortical region of the ovary had been recruited into primordial follicles in the control littermate mice. (D) However, Vasa-positive germ cells in the cortical region of the Amhr2-Cre/+;Notch2^flox/- mice were still in germ-cell nests (white arrows) at PND3. Cuboidal granulosa cells of primary follicles in the medulla of both littermate and mutant ovaries expressed anti-Müllerian hormone (AMH; green). Cell nuclei were counterstained with 4',6-diamidino-2-phenylindole (DAPI) (blue). (E) Laminin immunostaining (green) showed that by PND3, primordial follicles in the cortex of the ovary of control littermate mice were surrounded by a layer of basement membrane. (F) However, in Amhr2-Cre/+;Notch2^flox/- mice ovaries at the same stage, the oocytes remained in germ-cell cysts and were not individually surrounded by a basement membrane. Scale bar: (A, B): 20 μm; (C-F): 50 μm.