[Frontiers in Bioscience E4, 2579-2585, June 1, 2012]

MicroRNA-27a activity is not suppressed in porcine oocytes

Li Chen1, Xiaoxiang Hu1, Yunping Dai2, Qinghe Li1, Xiaobo Wang3, Qiuyan Li2, Kai Xue4,Yan Li2, Jingwen Liang1, Yuanyuan Wang1, Xiaojuan Liu1, Ning Li1

1State Key Laboratory for AgroBiotechnology, College of Biological Sciences, China Agricultural University, Beijing 100193, China, 2Ji Pulin biotech Ltd, Beijing 100193, China, 3Center for Cardiovascular Sciences, Albany Medical College, Albany, NY 12208, 4Dalian Medical University, Dalian 116044, China

TABLE OF CONTENTS

1. Abstract
2. Introduction
3. Materials and methods
3.1. Oocyte collection and culture
3.2. Evaluation of meiotic stages of porcine oocytes
3.3. MicroRNA expression profiling assay and analysis
3.4. Taqman real-time PCR of miRNAs
3.5. Bioinformatics method
3.6. Microinjection
3.7. Western blot analysis
3.8. Transfection and luciferase assay
3.9. Statistical analysis
4. Results
4.1. Meiotic stages of porcine oocytes during in vitro maturation
4.2. miRNA expression profiling during porcine oocyte maturation
4.3. miR-27a facilitates the first cell cleavage
4.4. miR-27a represses translation of MAP2K4
5. Discussion
6. Acknowledgment
7. References

1. ABSTRACT

MicroRNAs (miRNAs) are a class of small noncoding RNAs involved in multiple cellular processes. Recent findings indicate that miRNA activity is globally suppressed in mouse oocytes. However, whether miRNAs are expressed and function in porcine oocytes remains unknown. In this study, our aims were to ascertain if miRNA biogenesis occurs and whether miRNA activity is globally suppressed during porcine oocyte maturation. First, to identify if miRNA biogenesis occurred, a TaqMan low-density array containing 365 mature human miRNAs was used to examine miRNA expression. This analysis revealed dynamic changes in miRNA expression, suggesting miRNA biogenesis during porcine oocyte maturation. Then, to identify if miRNA activity was globally suppressed in porcine oocytes, we focused on miR-27a, which functions in the cell cycle. miR-27a was found to facilitate the first cleavage and repress the translation of its messenger RNA target (MAP2K4), suggesting that miR-27a activity was not suppressed in porcine oocytes. Taken together, our results suggest that miRNA activity was not globally suppressed in porcine oocytes, at least for miR-27a. However, because we only investigated the activity of miR-27a, further experiments are definitely required to ascertain this point.