MicroRNA in the ovary and female reproductive tract.

Posttranscriptional gene regulation plays a vital role in male and female germ cell function, but our understanding of this regulatory process in somatic cells and its effect on reproductive tissue development and function is not understood. In mammalian cells, microRNA (miRNA) are key posttranscriptional regulators and function by modulating translation or degradation of their target mRNA. Mature miRNA are synthesized through a multi-step process that concludes with the cleavage of stem-loop pre-miRNA by the RNase III enzyme, Dicer1. To determine the extent of miRNA regulation and establish a baseline, miRNA profiling has indicated the presence of large numbers of miRNA within reproductive tissues and cells. Moreover, several studies have indicated that miRNA expression in reproductive tissues varies in response to pituitary and gonadal hormones. To understand the role that miRNA-mediated posttranscriptional gene regulation plays in female reproduction, a global Dicer1 hypomorph mouse and several tissue-specific Dicer1 knockout mice have been studied. Interestingly, when Dicer1 expression is decreased in reproductive tissues or cells, the females are infertile. This review discusses all the work regarding miRNA regulation within the mammalian female reproductive system published to date.