To study the action of CYP51 on germ cell cyst breakdown that occurs around birth (19.5 dpc) in mice ovaries, 14.5 dpc ovaries were cultured for 8 days (equaling 3 dpp, when primordial follicle formation completed) through either knockdown of Cyp51 or inhibition of CYP51 activity. The gene discussed is CYP51A1; the disease is cyst.