Song Zhenhua, Min Lingjiang, Pan Qingjie, Shi Qinghua, Shen Wei
Qingdao Agricultural University, China.
Biochem Biophys Res Commun. 2009 Oct 2;387(4):800-5. doi: 10.1016/j.bbrc.2009.07.131. Epub 2009 Jul 30.
Epigenetic regulation of gene expression is critical for oogenesis in mammals. In this study, a simple and efficient method was used to obtain the oocytes from cultured fetal mouse ovaries of 12.5dpc. The methylation pattern of these oocytes was examined. The results showed that the establishment of imprinting of Igf2r and Peg3 in oocytes derived from cultured fetal mouse germ cells in vitro follows a slower time course than that of oocytes in vivo. However, oocytes in vitro and in vivo share similar methylation patterns. Igf2r was gradually de novo methylated, and the methylation covers 80% CpG sites in oocytes cultured for 28days. However, only 45% of the CpG sites is methylated in Peg3 at the same stage. Furthermore, it demonstrated that the degree of DNA methylation is positively correlated with the size of oocytes in vitro and in vivo, indicating a progressive methylation process during oocyte growth.
基因表达的表观遗传调控对哺乳动物的卵子发生至关重要。在本研究中，采用一种简单有效的方法从12.5天妊娠龄的培养胎鼠卵巢中获取卵母细胞。检测了这些卵母细胞的甲基化模式。结果表明，体外培养的胎鼠生殖细胞来源的卵母细胞中Igf2r和Peg3印记的建立比体内卵母细胞的时间进程要慢。然而，体外和体内的卵母细胞具有相似的甲基化模式。Igf2r逐渐发生从头甲基化，在培养28天的卵母细胞中，甲基化覆盖80%的CpG位点。然而，在同一阶段，Peg3中只有45%的CpG位点发生甲基化。此外，研究表明，体外和体内卵母细胞中DNA甲基化程度与卵母细胞大小呈正相关，表明卵母细胞生长过程中存在渐进性甲基化过程。
