Postnatal folliculogenesis in the Cx43 null mutant ovary

Connexin43 (Cx43) is one of the connexins involved in ovarian inter-granulosa cell communication. As the Cx43 null mutant mouse ( Gjal-/-) dies shortly after birth, I chose to explore postnatal folliculogenesis by employing an ovarian grafting procedure. I have shown that Gjal-/- folliculogenesis arrests in early stages, unlike grafted Gjal+/+ ovaries. Ultrastructural studies showed that these Gjal -/- contain many abnormalities and in vitro maturation and fertilization studies demonstrated that the oocytes from the Gjal-/- ovaries are not maturable or fertilizable. The granulosa cells from the Gjal-/- ovaries are able to transfer dye from cell to cell as was assayed via a preloading/dye coupling assay, suggesting that these granulosa cells are able to form gap junctions composed of other connexins. These data suggest that proper communication between the granulosa cells via Cx43-containing gap junctions is fundamental for their proliferation and that the proper growth of these cells is necessary for the growth the oocyte.