[Frontiers in Bioscience 14, 3239-3245, January 1, 2009]

A network of miRNAs expressed in the ovary are regulated by FSH

Nan Yao1,2,3, Cai-ling Lu2,3, Jian-jun Zhao1,2,3, Hong-fei Xia1,3, Da-guang Sun1,2,3, Xin-quan Shi1,3, Chong Wang1,2,3, Dan Li1,2,3, Yi Cui1,3, Xu Ma1,2,3

1Graduate School of Peking Union Medical College, Beijing, China, 2Department of Genetics, National Research Institute for Family Planning, Beijing, China, 3World Health Organization Collaborative Center for Research in Human Reproduction, Beijing, China

TABLE OF CONTENTS

1. Abstract
2. Introduction
3. Materials and methods
3.1. Tissue collection and processing
3.2. Northern blotting
3.3. Locked nucleic acid (LNA)-modified-In situ hybridization for miRNAs
3.4. Cell culture
3.5. TaqMan miRNA expression assays
4. Results
4.1. miRNA expression in tissues of adult female mice
4.2. Expression of miRNAs in the follicles of adult female mice
4.3. Regulation of the expression of miRNAs by FSH
5. Discussion
6. Acknowledgments
7. References

1. ABSTRACT

The process of folliculogenesis requires a tightly regulated series of gene expression that are a pre-requisite to the development of ovarian follicle. Among these genes, follicle-stimulating hormone (FSH) is notable for its dual role in proliferation and development of follicles as well as differentiation of granulosa cells. The post-transcriptional expression of these genes is under the control of microRNAs (miRNAs), a class of small, endogenous RNAs that negatively impact gene expression. This study was carried out to determine the role of several miRNAs including mir-143, let-7a, mir-125b, let-7b, let-7c, mir-21 in follicular development in the mouse. The expression of these RNAs was very low in primordial follicles but these became readily detectable in the granulosa cells of primary, secondary and antral follicles. We show that this expression is under negative control of FSH. FSH inhibited the expression of some (mir-143, let-7a, mir-125b) but not all of these RNAs. Together, these findings suggest that FSH regulates folliculogenesis by a network of miRNAs.