Aberrant expression and methylation status of putatively imprinted genes in placenta of cloned piglets.
Aberrant expression and methylation status of putatively imprinted genes in placenta of cloned piglets.
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DOI：
10.1089/cell.2009.0090
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发表时间：
2010-04
影响因子：
1.6
通讯作者：
Yanchang Wei;Jiang Zhu;Yanjun Huan;Zhongfeng Liu;Cai-Xia Yang;Xinmiao Zhang;Y. Mu;P. Xia;
中科院分区：
文献类型：
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作者：
Yanchang Wei;Jiang Zhu;Yanjun Huan;Zhongfeng Liu;Cai-Xia Yang;Xinmiao Zhang;Y. Mu;P. Xia;
与受精产生的胚胎不同，大多数克隆胚胎在植入后发育过程中死亡，而那些存活到足月的胚胎往往有缺陷。许多观察到的缺陷都涉及胎盘。一些克隆物种的胎盘异常已被描述。印记基因是胎盘生长的重要调节因子，并且可能在体细胞核移植过程中遭受错误的重编程。我们的目的是确定活克隆仔猪和死亡仔猪胎盘中印记基因的表达水平和甲基化模式。实时定量逆转录聚合酶链式反应 (RT-PCR) 分析显示，与活克隆仔猪和对照胎盘相比，死亡克隆仔猪胎盘中所有四种印记基因（IGF2、H19、PEG3 和 GRB10）的表达均显着降低（p < 0.05）。活体克隆中这些基因的转录水平与仔猪和胎盘中的对照几乎没有差异。对H19基因的IGF2和CTCF3的DMR2甲基化状态的检查表明，与活克隆和对照的胎盘相比，死克隆的胎盘中这两个基因都表现出显着高的甲基化水平。相比之下，与对照相比，这两个基因在活体克隆仔猪及其胎盘中均显示出正常的差异甲基化模式。重要的是，死亡的克隆仔猪也表现出正常的模式。我们的研究结果表明，胎盘中印记基因的异常表达可能导致猪体细胞核移植（SCNT）的发育失败，这可能是由于SCNT期间不完全重编程导致印记基因差异甲基化区域（DMR）的异常甲基化模式引起的。
Unlike embryos derived from fertilization, most cloned embryos die during postimplantation development, and those that survive to term are frequently defective. Many of the observed defects involve placenta. Abnormal placentation has been described in several cloned species. Imprinted genes are important regulators of placenta growth, and may be subjected to faulty reprogramming during somatic cell nuclear transfer. We aimed to determine the expression levels and methylation patterns of imprinted genes in placentas of live cloned piglets and dead ones. Quantitative real-time reverse transcriptase-polymerase chain reaction (RT-PCR) analysis showed that the expression of all four imprinted genes (IGF2, H19, PEG3, and GRB10) was significantly reduced in placentas of dead clones compared with placentas of live cloned piglets and controls (p 0.05). Transcript levels for these genes in live clones rarely differed from those of controls in both piglets and placentas. Examination of the methylation status of DMR2 of IGF2 and CTCF3 of H19 genes revealed that both genes exhibited significant high methylation levels in placentas of dead clones compared with placentas of live clones and controls. In contrast, both genes showed a normal differential methylation pattern in live cloned piglets and their placentas compared with controls. Importantly, dead cloned piglets also showed a normal pattern. Our results suggest that abnormal expression of imprinted genes in placenta may contribute to the development failure in pig somatic cell nuclear transfer (SCNT), which may be caused by abnormal methylation patterns in differentially methylated regions (DMRs) of imprinted genes as a result of incomplete reprogramming during SCNT.