microRNAs are necessary for procreation
Recently discovered microRNAs provide one of the mechanisms for regulating gene expression – the conversion of genetic information into proteins. New data obtained by scientists at the Scripps Research Institute, working under the leadership of Dr. Jiahuai Han, indicate that microRNAs affect the ability of mice to reproduce offspring.
microRNA synthesis is a complex process involving the enzyme Dicer1. The authors found that transgenic mice of the Dicer d/d line, characterized by significantly reduced levels of Dicer1 protein compared to the norm, have one defect – their females are infertile. The cause of infertility in this case is a violation of the functioning of the corpus luteum – a structure that forms in the ovary at the site of the released fertilized egg and synthesizes hormones necessary to maintain pregnancy in the early stages.
A detailed analysis showed that the functioning of the corpus luteum is impaired as a result of the inability to form new blood vessels associated with the lack of two microRNAs: miR17-5p and let7b, regulating the expression of tissue metalloproteinase-1 inhibitor (TIMP1), suppressing angiogenesis.
The introduction of these microRNAs into the ovaries of experimental animals reduced the expression of TIMP1 and increased the number of blood vessels in the corpus luteum. Based on these results, the authors concluded that the development and functioning of the corpus luteum is regulated by microRNAs.
Become Motoyuki Otsuka et al. "Impacted microRNA processing causes corpus luteum insufficiency and infertility in mice" published in the Journal of Clinical Investigation on April 8, 2008.