China Animal Husbandry and Veterinary Medicine ›› 2022, Vol. 49 ›› Issue (7): 2661-2668.doi: 10.16431/j.cnki.1671-7236.2022.07.024

• Genetics and Breeding • Previous Articles     Next Articles

Effects of miR-449b on Early Embryo Development in Sheep

REN Xiumeiao1,2, YAO Xudong1,2, MENG Yaqi1,2, GUO Yanhua2, TANG Hong2, ZHANG Yiyuan2, ZHAO Xingwang3, WANG Limin2, ZHOU Ping1,2   

  1. 1. College of Animal Science and Technology, Shihezi University, Shihezi 832000, China;
    2. State Key Laboratory of Sheep Genetic Improvement and Healthy Production, Xinjiang Academy of Agricultural Reclamation Sciences, Shihezi 832000, China;
    3. Agricultural Service Development Center of Shihezi General Farm, Shihezi 832000, China
  • Received:2021-12-15 Online:2022-07-05 Published:2022-06-29

Abstract: 【Objective】 The study was to investigate the effect of miR-449b on early embryo development in sheep.【Method】 Purified sheep sperm and mature oocytes were obtained by Percoll density gradient centrifugation and in vitro maturation of cumulus-oocyte complexes (COCs) for 16-18 h,respectively.And fibroblasts were isolated from the ear tissues of one-month-old Suffolk sheep.Firstly,the relative expression of miR-449b in sperms,mature oocytes and fibroblasts were compared by Real-time quantitative PCR.Mature oocytes were injected with 0.9% normal saline (Con group),NC mimic (NC mimic group) and miR-449b mimic (miR-449b mimic group) by microinjection,respectively.Then the embryonic cleavage rate and blastocyst rate were counted on the 2nd and 7th day after parthenogenetic activation. Mature oocytes were fertilized in vitro (IVF), 2-cell embryos in IVF, Con, NC mimic and miR-449b mimic groups were collected, and the changes of histone H3K9me3 were compared by immunofluorescence method. 【Result】 The expression of miR-449b in sperm was significantly higher than that in mature oocytes and fibroblasts (P<0.05). Compared with Con group, the cleavage rates of embryos in miR-449b mimic and NC mimic groups were significantly decreased (P<0.05), and the cleavage rate of embryos in NC mimic group was significantly lower than that of miR-449b mimic group (P<0.05). The blastocyst rate of embryos in miR-449b mimic group was increased, but the difference was not significant (P>0.05). Histone H3K9me3 was expressed in 2-cell embryos in IVF, Con, NC mimic and miR-449b mimic groups, and was expressed in the nucleus. Compared with Con group, the expression level of histone H3K9me3 in 2-cell embryos in NC mimic group was significantly increased (P<0.05), and was significantly decreased in miR-449b mimic group (P<0.05). The expression level of histone H3K9me3 in 2-cell embryos in NC mimic group was significantly higher than that in miR-449b mimic group (P<0.05), but there was no significant difference between miR-449b mimic and IVF groups (P>0.05). 【Conclusion】 miR-449b could significantly increase the development rate of early sheep embryos and reduce the expression of H3K9me3 in early embryos.

Key words: miR-449b; early embryo; H3K9me3; sperm

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