Minor and major zygotic genome activation (ZGA) are crucial for preimplantation development. During this process, histone variants and methylation influence chromatin accessibility and consequently regulated the expression of zygotic genes. However, the detailed exchanges of these modifications during ZGA remain to be determined. In the present study, the epigenetic modifications of histone 3 on lysine 9 (H3K9), 27 (H3K27) and 36 (H3K36), as well as four histone variants were determined during minor and major ZGA and in post-ZGA stages of mouse embryos. Firstly, microH2A1, H3K27me3 and H3K36me3 were asymmetrically stained in the female pronucleus during minor ZGA but lost staining in major ZGA. Secondly, H3K9me2 and H3K9me3 were strongly stained in the female pronucleus, but weakly stained in the male pronucleus and disappeared after ZGA. Thirdly, H2A.Z and H3.3 were symmetrically stained in male and female pronuclei during minor ZGA. Moreover, H3K27me2 was not statistically changed during mouse early development, while H3K36me2 was only detected in 2- and 4-cell embryos. In conclusion, our data revealed dynamics of histone methylation and variants during mice ZGA and provided details of their exchange in mice embryogenesis. Moreover, we further inferred that macroH2A1, H2A.Z, H3K9me2/3 and H3K27me2/3 may play crucial roles during mouse ZGA.

次要和主要合子基因组激活（ZGA）对于植入前的发展至关重要。在此过程中，组蛋白变体和甲基化会影响染色质的可及性，从而调节合子基因的表达。但是，在ZGA期间这些修改的详细交换还有待确定。在本研究中，确定了组蛋白3在赖氨酸9（H3K9），27（H3K27）和36（H3K36）的表观遗传修饰以及四个组蛋白变体在小鼠胚胎的次要和主要ZGA以及ZGA后阶段。首先，microH2A1，H3K27me3和H3K36me3在未成年人ZGA期间在女性原核中不对称染色，但在主要ZGA中丢失了染色。其次，H3K9me2和H3K9me3在雌性原核中被强烈染色，而在雄性原核中被弱染色，并在ZGA后消失。第三，H2A.Z和H3.3在未成年人ZGA期间在男性和女性原核中对称染色。此外，H3K27me2在小鼠早期发育过程中没有统计学变化，而H3K36me2仅在2细胞和4细胞胚胎中检测到。总之，我们的数据揭示了小鼠ZGA期间组蛋白甲基化和变异的动力学，并提供了它们在小鼠胚胎发生中的交换细节。此外，我们进一步推断macroH2A1，H2A.Z，H3K9me2 / 3和H3K27me2 / 3在小鼠ZGA期间可能起关键作用。我们的数据揭示了小鼠ZGA期间组蛋白甲基化和变异的动力学，并提供了它们在小鼠胚胎发生中的交换细节。此外，我们进一步推断macroH2A1，H2A.Z，H3K9me2 / 3和H3K27me2 / 3在小鼠ZGA期间可能起关键作用。我们的数据揭示了小鼠ZGA期间组蛋白甲基化和变异的动力学，并提供了它们在小鼠胚胎发生中的交换细节。此外，我们进一步推断macroH2A1，H2A.Z，H3K9me2 / 3和H3K27me2 / 3在小鼠ZGA期间可能起关键作用。