Key Laboratory of Animal Cellular and Genetic Engineering of Heilongjiang Province, College of Life Science, Northeast Agricultural University, Harbin 150030, China.
Key Laboratory of Animal Resistance Biology of Shandong Province, College of Life Science, Shandong Normal University, Jinan 250014, China.
Biol Reprod. 2023 Jun 9;108(6):902-911. doi: 10.1093/biolre/ioad029.
N6-methyladenosine (m6A), an epigenetic modification on RNAs, plays an important role in many physiological and pathological processes. However, the involvement of m6A in goat uterus during early pregnancy remains largely unknown. In this study, we found that the total m6A level was increasing in goat uterus as early pregnancy progressed. Methyltransferase-like 3 (METTL3) is a core catalytic subunit of the m6A methyltransferase. We thus determined the expression and regulation of METTL3 in goat uterus. METTL3 was highly expressed in the luminal and glandular epithelia from day 16 (D16) to D25 of pregnancy, and it could be up-regulated by estrogen and progesterone in goat uterus and primary endometrial epithelial cells (EECs). In EECs, knockdown or overexpression of METTL3 resulted in a significant decrease or increase of cell proliferation, respectively. METTL3 knockdown reduced the m6A level of not only total RNA but also connective tissue growth factor (CTGF) mRNA. Luciferase assay suggested that METTL3 might target the potential m6A sites in the 3'untranslated region (3'UTR) of CTGF mRNA. Moreover, METTL3 positively regulated CTGF expression, and CTGF knockdown significantly counteracted the promoting effect of METTL3 overexpression on EEC proliferation. Collectively, METTL3 is dynamically expressed in goat uterus and can affect EEC proliferation by regulating CTGF in an m6A-dependent manner. Our results will lay a foundation for further studying the crucial mechanism of METTL3-mediated m6A modification in goat uterus during early pregnancy.
N6-甲基腺苷（m6A）是 RNA 上的一种表观遗传修饰，在许多生理和病理过程中发挥着重要作用。然而，m6A 在山羊子宫早期妊娠中的参与仍然知之甚少。在这项研究中，我们发现随着早期妊娠的进展，山羊子宫中的总 m6A 水平逐渐增加。甲基转移酶样 3（METTL3）是 m6A 甲基转移酶的核心催化亚基。因此，我们确定了 METTL3 在山羊子宫中的表达和调节。METTL3 在妊娠第 16 天（D16）至第 25 天的腔上皮和腺上皮中高度表达，并且可以在山羊子宫和原代子宫内膜上皮细胞（EEC）中被雌激素和孕激素上调。在 EEC 中，METTL3 的敲低或过表达分别导致细胞增殖显著减少或增加。METTL3 敲低不仅降低了总 RNA 的 m6A 水平，也降低了结缔组织生长因子（CTGF）mRNA 的 m6A 水平。荧光素酶报告基因实验表明，METTL3 可能靶向 CTGF mRNA 3'非翻译区（3'UTR）中的潜在 m6A 位点。此外，METTL3 正向调节 CTGF 的表达，而 CTGF 的敲低显著抵消了 METTL3 过表达对 EEC 增殖的促进作用。总之，METTL3 在山羊子宫中动态表达，可通过调节 CTGF 以 m6A 依赖的方式影响 EEC 增殖。我们的研究结果将为进一步研究 METTL3 介导的 m6A 修饰在山羊子宫早期妊娠中的关键机制奠定基础。
