Samarin Azin Mohagheghi, Samarin Azadeh Mohagheghi, Waghmare Swapnil Gorakh, Danielsen Marianne, Møller Hanne Søndergård, Policar Tomáš, Linhart Otomar, Dalsgaard Trine Kastrup
South Bohemian Research Center of Aquaculture and Biodiversity of Hydrocenoses, Research Institute of Fish Culture and Hydrobiology, Faculty of Fisheries and Protection of Waters, University of South Bohemia in Ceske Budejovice, 389 25 Vodňany, České Budějovice, Czech Republic.
Department of Food Science, Aarhus University, Agro Food Park 48, 8200, Aarhus, Denmark.
Fish Physiol Biochem. 2024 Oct;50(5):2013-2024. doi: 10.1007/s10695-023-01273-7. Epub 2023 Nov 29.
Delayed fertilization leads to the ageing of post-ovulatory oocytes and reduces the developmental competence of arising embryos. Little information is available about the molecular processes during fish oocyte ageing. The current study investigated the functional consequences of oocyte ageing in grass carp Ctenopharyngodon idella embryos. In addition, the dynamics of selected post-transcriptionally modified histones (acetylation of H3K9, H3K14, H4K5, H4K8, H4K12, and H4K16) were analyzed during oocyte ageing. Ovulated oocytes were aged in vitro for 4 h in the laboratory incubator at 20 °C and studied for selected post-translational modification of histones. In addition, histone acetyltransferase activity was investigated as an important regulator of histone acetylation modification. The results indicated a significant decrease in oocyte fertilizing ability through 1 h of post-ovulatory ageing, and a complete loss of egg fertilizing abilities was detected at 4-h aged oocytes. Furthermore, post-ovulatory oocyte ageing for 1 and 4 h led to decreased levels of H4K12 acetylation. The activity of histone acetyltransferases increased significantly after ageing of the oocytes for 30 h in vitro. This modification may partly contribute to explaining the failures of egg viability and embryo development in the offspring from the aged oocytes. The results are the first to report histone modifications as a crucial epigenetic regulator during oocyte ageing in fish and might also benefit other vertebrates.
延迟受精会导致排卵后卵母细胞老化，并降低所产生胚胎的发育能力。关于鱼类卵母细胞老化过程中的分子机制，目前所知甚少。本研究调查了草鱼（Ctenopharyngodon idella）卵母细胞老化对胚胎的功能影响。此外，还分析了在卵母细胞老化过程中，选定的转录后修饰组蛋白（H3K9、H3K14、H4K5、H4K8、H4K12和H4K16的乙酰化）的动态变化。将排卵后的卵母细胞在实验室培养箱中于20°C体外老化4小时，并研究组蛋白的选定翻译后修饰。此外，还研究了组蛋白乙酰转移酶活性作为组蛋白乙酰化修饰的重要调节因子。结果表明，排卵后老化1小时，卵母细胞受精能力显著下降，老化4小时的卵母细胞则完全丧失了受精能力。此外，排卵后卵母细胞老化1小时和4小时会导致H4K12乙酰化水平降低。卵母细胞在体外老化30小时后，组蛋白乙酰转移酶的活性显著增加。这种修饰可能部分有助于解释老化卵母细胞后代的卵子活力和胚胎发育失败的原因。这些结果首次报道了组蛋白修饰是鱼类卵母细胞老化过程中的关键表观遗传调节因子，也可能对其他脊椎动物有益。
