[Frontiers in Bioscience 18, 588-597, January 1, 2013]

miR-143 is critical for the formation of primordial follicles in mice

Jianfang Zhang, Xiaowen Ji, Doudou Zhou, Yueqin Li, Junkai Lin, Jiali Liu, Haoshu Luo, Sheng Cui

State Key Laboratory for Agro-biotechnology, College of Biological Sciences, China Agricultural University, Beijing, 100193, P.R. China


1. Abstract
2. Introduction
3. Materials and methods
3.1 .Animals (ethics statement)
3.2. In situ hybridization
3.3. Real-time polymerase chain reaction assay
3.4. Isolation, electrotransfection and cultivation of mouse ovaries
3.5. Immunohistochemistry
3.6. Ovarian follicle counts
3.7. BrdU analysis
3.8. Cell culture and miRNA transfection
3.9. Statistical analysis
4. Results
4.1. miR-143 expression during the formation of primordial follicles
4.2. Electroporation transfection of miR-143 mimics and miR-143 inhibitors
4.3. miR-143 inhibits the formation of primordial follicles
4.4. miR-143 inhibits the proliferation of pregranulosa cells
4.5. Effects of miR-143 on the expression of genes related to the cell cycle
5. Discussion
6. Acknowledgements
7. References


Although microRNAs (miRNAs) have been implicated in fine-tuning gene networks, the roles of mmu-mir-143 (miR-143) in mammalian ovary development have not been studied in vitro. We investigated the expression and function of miR-143 in the mouse ovary during primordial follicle formation. Real-time polymerase chain reaction analysis showed that miR-143 expression increased during primordial follicle formation from 15.5 days post-coitus to 4 days post-partum. miR-143 was located in pregranulosa cells by in situ hybridization. To study the function of miR-143 in primordial follicle formation we established an electroporation transfection model in vitro that allowed miR-143 expression to be efficiently upregulated and inhibited in cultured ovaries. Further studies showed that miR-143 inhibited the formation of primordial follicles by suppressing pregranulosa cell proliferation and downregulating the expression of genes related to the cell cycle. These findings suggest that miR-143 is critical for the formation of primordial follicles and regulates ovarian development and function.