Fig. 4. Restoration of oocyte–granulosa-cell coupling in Cx37-deficient follicles by replacement with Cx43. Injection of Lucifer yellow into oocytes (O) of follicles from Cx37-deficient mice (A,B) did not result in dye transfer to the surrounding granulosa cells. By contrast, dye injected into oocytes of follicles from Cx37-deficient mice carrying the transgene (C,D) and from wild-type mice (E,F) passed readily into the surrounding granulosa cells. Bar, 50 µm.