Fig. 4. Oocyte-granulosa cell coupling is maintained in the absence of Cx43. Wild type (A,B) and Cx43-deficient (C,D) follicles were isolated, cultured, and oocytes were microinjected with the gap-junction-permeable dye, Lucifer yellow. Dye transferred throughout the wild-type follicle after oocyte injection (B), whereas dye spread to only the first layer of granulosa cells directly in contact with the oocyte in Cx43-deficient follicles (D). Bar=50 µm.