Tiny molecules called miRNAs influence fertility of female mice besides regulating the conversion of genetic information to proteins, a new study has indicated.
miRNAs are usually generated naturally by the body, which is a complex process that involves a protein known as Dicer.
In the study, by Jiahuai Han and colleagues at The Scripps Research Institute, La Jolla, females of mice expressing substantially lower levels of Dicer than normal mice (Dicerd/d mice), were found to be infertile.
It was found that infertility was caused due to impaired functioning of the corpus luteum, the structure that forms at the site of release of the fertilized egg and that is required to maintain pregnancy at the early stages.
After detailed analysis it was found that the functioning of the corpus luteum was impaired because it was unable to form new blood vessels, and that this was associated with increased expression of the protein TIMP1, which inhibits blood vessel formation.
When the miRNAs miR17-5p and let7b were injected into the ovaries of Dicerd/d mice, the expression of TIMP1 was decreased and the number of blood vessels in the corpus luteum increased.
This made the authors conclude that the development and function of the corpus luteum in mice is tightly regulated by miRNAs.
The study is published in the Journal of Clinical Investigation.