Acta Veterinaria et Zootechnica Sinica ›› 2024, Vol. 55 ›› Issue (11): 5035-5049.doi: 10.11843/j.issn.0366-6964.2024.11.021

• Animal Biotechnology and Reproduction • Previous Articles     Next Articles

The Study of Regulatory Effect of Differentially Expressed microRNAs on the Npm2 Expression in Pig Oocytes

Helin LI1,3(), Yufen JIANG1,3(), Na CHENG1,3, Yuchen HAN1,3, Xiaoying HUO2,3, Hongding SU3, Yue CHANG1,3, Yuzhu FANG2,3, Pei WANG1,3, Baoyu JIA2,3, Hongjiang WEI2,3,*(), Wenmin CHENG1,3,*()   

  1. 1. College of Animal Science and Technology, Yunnan Agricultural University, Kunming 650201, China
    2. College of Veterinary Medicine, Yunnan Agricultural University, Kunming 650201, China
    3. Yunnan Key Laboratory of Porcine Gene Editing and Xenotransplantation, Kunming 650201, China
  • Received:2024-03-29 Online:2024-11-23 Published:2024-11-30
  • Contact: Hongjiang WEI, Wenmin CHENG E-mail:sonnyspike@163.com;2962181956@qq.com;hongjiangwei@126.com;cheng_8097@163.com

Abstract:

This study aimed to explore the regulatory effect of differentially expressed microRNAs on Npm2 (nucleoplasmin 2) in pig oocytes. The GV-stage oocytes were collected from slaughterhouse ovaries, cultured in vitro. The expression levels of screened miRNA in GV and MⅡstage oocytes were detected using qPCR. The dual-luciferase reporter experiment was performed to verify the binding site of predicted miRNA with target gene Npm2. Further, miRNAs mimics/inhibitors were added to in vitro maturation medium to evaluate the effect of miRNA on the developmental ability of oocytes and parthenogenetic activated embryos. After the optimal concentration of miRNAs mimics/inhibitors were added, peanut agglutinin staining test was used to detect cortical granule distribution and Npm2 mRNA expression level was detected using qPCR. The results showed that, compared with GV stage oocytes, the expression levels of miR-150 and miR-7138-5p were significantly higher (P < 0.05) and the expression levels of miR-296-3p and miR-423-3p were significantly lower in MⅡ oocytes (P < 0.01), which were consistent with the previous sequencing results. There was no significant difference in the expression levels of miR-32 (P>0.05). The double luciferase assay showed that miR-32, miR-7138-5p, miR-296-3p and miR-150 had binding sites with Npm2, while the fluorescence intensity was significantly down-regulated (P < 0.05). There was no binding site between miR-296-5p, miR-423-3p and Npm2, as the fluorescence intensity was comparable (P>0.05). The optimal concentration of miRNAs mimics/inhibitors was determined. After addition of miR-32 inhibitor, miR-296-5p mimics, miR-296-5p inhibitor, miR-423-3p mimics, miR-423-3p inhibitor, miR-7138 inhibitor, miR-150 mimics and miR-150 inhibitor, cortical particle fluorescence intensity was significantly decreased (P < 0.01). The cortical particle fluorescence intensity was significantly decreased after the addition of miR-296-3p inhibitor and miR-7138-5p mimics (P < 0.05). The expression of Npm2 mRNA in MⅡ oocytes was significantly higher than that in GV oocytes, and after the addition of the optimal concentration of miR-150, miR-296-3p, miR-296-5p, miR-7138-5p mimics and/or inhibitors, the expression of Npm2 in MⅡ oocytes had significant differences compared with the GV oocytes (P < 0.05). There was no significant difference in the expression of Npm2 mRNA after miR-32 and miR-423-3p mimics/inhibitors in MⅡ oocytes compared with control group (P>0.05). These findings indicated that the screened miRNAs may affect oocyte maturation and early embryo development in vitro by regulating Npm2 expression.

Key words: pig, oocyte, microRNA, Npm2

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