The present study was designed to investigate the comprehensive function of maternal factors of primordial germ cell 7 (PGC7) and POU5F1-POU class 5 homeobox 1 (OCT4), as well as the epigenetic modification roles on the mitosis for the extrusion of first polar body (PB1) in pig maturated oocytes. First, the common distribution of histone modifications, including H3K4me2, H3K27me3, H3K9me2, and H4K12ac and DNA methylation, were detected at the high level in the nucleus. However, only one part of the chromosome was higher methylated or acetylated when the mitosis happened to extrude the PB1. When the mitosis was inhibited by the cytochalasin B (CB) treatment, the expression of PGC7, OCT4, DNA methyltransferase1 (DNMT1), DNA methyltransferase3b (DNMT3b), tet methylcytosine dioxygenase 1 (TET1), tet methylcytosine dioxygenase 2 (TET2), and tet methylcytosine dioxygenase 3 (TET3) could be inhibited (p < 0.01), and no concentrated expression of the PGC7 and OCT4 was observed on the chromosome, but the levels of H3K9me2 and H4K12ac were higher. In addition, when the trichostatin A was performed on the in vitro maturation, the extrusion of the PB1 was inhibited too. And the histone methylation (H3K9me2 and H3K27me3) could be detected all the time with relative higher level and no demethylation could be observed. However, the expression of PGC7 and OCT4 was lower in the chromosome. It might indicate that the maternal factor of PGC7 and histone modification that included H4K12ac and H3K9me2 could regulate the extrusion of the PB1 and play an important role in the maturation of pig oocytes.

中文翻译：

---

表观遗传变化对猪卵母细胞体外成熟过程中第一极体挤出的影响。


本研究旨在探讨原始生殖细胞7（PGC7）和POU5F1-POU 5类同源盒1（OCT4）母体因素的综合功能，以及表观遗传修饰对有丝分裂第一极体挤出的作用。 (PB1) 在猪成熟卵母细胞中。首先，在细胞核中检测到高水平的组蛋白修饰的常见分布，包括 H3K4me2、H3K27me3、H3K9me2 和 H4K12ac 以及 DNA 甲基化。然而，当有丝分裂碰巧挤出PB1时，只有一部分染色体被高度甲基化或乙酰化。当细胞松弛素 B (CB) 处理抑制有丝分裂时，PGC7、OCT4、DNA 甲基转移酶 1 (DNMT1)、DNA 甲基转移酶 3b (DNMT3b)、tet 甲基胞嘧啶双加氧酶 1 (TET1)、tet 甲基胞嘧啶双加氧酶 2 (TET2) 和tet甲基胞嘧啶双加氧酶3（TET3）受到抑制（p < 0.01），染色体上未观察到PGC7和OCT4的集中表达，但H3K9me2和H4K12ac的水平较高。另外，曲古抑菌素A进行体外成熟时，PB1的挤出也受到抑制。并且组蛋白甲基化（H3K9me2和H3K27me3）始终可以检测到，且水平相对较高，并且没有观察到去甲基化。然而，PGC7和OCT4在染色体中的表达较低。这可能表明PGC7的母体因子和包括H4K12ac和H3K9me2在内的组蛋白修饰可以调节PB1的挤出并在猪卵母细胞的成熟中发挥重要作用。