The development of mature eggs in the ovaries is a complex process driven by multiple genes, cascades of chemical signals, and the interactions of many different types of cells. By determining the roles of all the different players in this process, scientists can learn how the system breaks down to cause infertility.
Studies have suggested that two signaling molecules, called GATA-4 and GATA-6, regulate genes involved in female fertility. However, scientists do not yet fully understand exactly how these specific molecules affect fertility.
To learn more, researchers funded by the Fertility and Infertility Branch blocked the genes that code for GATA-4 and GATA-6 in female mice to see what would happen when those genes were missing. They found that the mice missing both molecules didn’t ovulate and were completely infertile. Mice that were missing only GATA-4 had lowered fertility, and those missing only GATA-6 seemed to have normal fertility.
The researchers also gathered information about the levels of other signaling molecules to learn how GATA-4 and GATA-6 fit in with the larger system of signals that control egg development. They found that GATA-4 boosts the effects of a critical hormone that drives the maturation of ovarian follicles so that they can release mature eggs.
The results show that GATA-4 and GATA-6 have slightly different, but overlapping, roles and have major effects on the development of eggs (PMID: 22434075).