The effects of postovulatory aging of mouse oocytes on methylation and expression of imprinted genes at mid-term gestation
The effects of postovulatory aging of mouse oocytes on methylation and expression of imprinted genes at mid-term gestation
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小鼠卵母细胞排卵后衰老对妊娠中期印记基因甲基化和表达的影响
DOI：
10.1093/molehr/gar018
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发表时间：
2011-09-01
影响因子：
4
通讯作者：
Sun, Qing-Yuan
中科院分区：
文献类型：
--
作者：
Liang, Xing-Wei;Ge, Zhao-Jia;Sun, Qing-Yuan
前人和我们的研究表明，卵母细胞中印迹基因的甲基化模式在排卵后衰老过程中发生了改变。本研究的目的是评估小鼠卵母细胞排卵后老化对妊娠中期印迹基因甲基化和表达的影响。在hcg后13 h（新鲜卵母细胞组）或22 h（老化卵母细胞组）进行人工授精。发情的雌性与雄性交配作为对照组。在交配后第10.5天采集胚胎和胎盘，分别提取DNA和RNA。分别采用PCR和实时荧光定量RT-PCR对Igf2r和H19的甲基化和总表达进行定量分析。我们的研究结果显示，无论人工授精新鲜或衰老的卵母细胞，胚胎和胎盘中差异甲基化区（DMR）的甲基化和Igf2r的总表达都没有显著变化，胚胎发育10.5 dpc时的H19甲基化与对照组相比没有显著变化。相比之下，衰老卵母细胞组的胎盘在H19 DMR中的甲基化水平显著降低。此外，我们观察到衰老卵母细胞组胎盘中H19表达的增加与H19 DMR的显著低甲基化有关。这些结果表明，小鼠卵母细胞的排卵后老化对妊娠中期胎盘中H19的甲基化和表达有不利影响。
Previous studies by others and ourselves have suggested that the methylation pattern of imprinted genes in oocytes is altered during postovulatory aging. The purpose of the current study was to evaluate the effects of postovulatory aging of mouse oocytes on methylation and expression of imprinted genes at the mid-gestation development stages. Proestrous females were artificially inseminated at 13 h (fresh-oocyte group) or 22 h (aged-oocyte group) post-hCG. Estrous females were mated with males as a control group. On dpc (day post coitus) 10.5 of development, embryos and placentas were collected and DNA and RNA were extracted, respectively. Methylation and total expression of Igf2r and H19 was investigated by quantitative analysis of methylation by PCR and quantitative real-time RT-PCR, respectively. Our results showed no significant changes of methylation in the differentially methylated region (DMR) and total expression of Igf2r in embryos and placentas, and no significant changes in methylation of H19 in embryos at dpc 10.5 of development compared with the control group regardless of artificial insemination of fresh or aged oocytes. In contrast, placentas of the aged-oocyte group exhibited significantly lower methylation levels in the H19 DMR. Furthermore, we observed that the increased expression of H19 in placentas of the aged-oocyte group was associated with significant hypomethylation of H19 DMR. These results suggest that postovulatory aging of mouse oocytes has adversed effects on methylation and expression of H19 in placentas at the mid-gestation development stage.