Tissue-specific elevated genomic cytosine methylation levels are associated with an overgrowth phenotype of bovine fetuses derived by in vitro techniques
Tissue-specific elevated genomic cytosine methylation levels are associated with an overgrowth phenotype of bovine fetuses derived by in vitro techniques
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DOI：
10.1095/biolreprod.103.026062
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发表时间：
2004-07-01
影响因子：
3.6
通讯作者：
Wolf, E
中科院分区：
文献类型：
--
作者：
Hiendleder, S;Mund, C;Wolf, E
表观遗传扰动被认为是负责异常观察胎儿和后代衍生的体外技术。我们设计了一项通过体细胞核移植（SCNT）、体外受精（IVF）和人工授精（AI）产生的牛第80天胎儿的实验，以确定胎儿表型与全基因组5-甲基胞嘧啶（5mC）含量之间的关系。与人工智能对照组相比，SCNT和IVF胎儿的体重（61%和28%）、肝脏重量（100%和36%）和胸围（20%和11%）均显著增加。冠臀长：胸围比减小（SCNT为1.175 +/- 0.017，IVF为1.292 bb0 0.018， AI为1.390 +/- 0.018,P < 0.001和P < 0.002）是这种不成比例过度生长表型的外部标志。与AI对照组相比，SCNT胎儿肝脏DNA高甲基化显著（3.46% +/- 0.08% vs. 3.17% +/- 0.09% 5mC, P < 0.03），体外受精胎儿胞嘧啶甲基化水平（3.34% +/- 0.09%）在表型参数上与其他组居中。胎儿体重、肝重、胸围对肝脏DNA 5mC含量的回归呈正相关（P < 0.073 ~ 0.079）。肝5mC与冠臀长胸围比呈显著负回归（P < 0.021）。胎盘子叶DNA中5mC的含量比肝脏DNA低46% (P < 0.0001)，但各组间差异不显著。这些数据与最近报道的SCNT胎儿DNA低甲基化形成鲜明对比，表明胎儿组织（而不是胎盘）的高甲基化与牛SCNT和体外受精胎儿的过度生长表型有关。
Epigenetic perturbations are assumed to be responsible for abnormalities observed in fetuses and offspring derived by in vitro techniques. We have designed an experiment with bovine Day 80 fetuses generated by somatic cell nuclear transfer (SCNT), in vitro fertilization (IVF), and artificial insemination (AI) to determine the relationship between fetal phenotype and genome-wide 5-methylcytosine (5mC) content. When compared with AI controls, SCNT and IVF fetuses displayed significantly increased body weight (61% and 28%), liver weight (100% and 36%), and thorax circumference (20% and 11%). A reduced crown-rump length:thorax circumference ratio (1.175 +/- 0.017 in SCNT and 1.292 > 0.018 in IVF vs. 1.390 +/- 0.018 in AI, P < 0.001 and P < 0.002) was the external hallmark of this disproportionate overgrowth phenotype. The SCNT fetuses showed significant hypermethylation of liver DNA in comparison with AI controls (3.46% +/- 0.08% vs. 3.17% +/- 0.09% 5mC, P < 0.03), and the cytosine methylation levels for IVF fetuses (3.34% +/- 0.09%) were, as observed for phenotypic parameters, intermediate to the other groups. Regressions of fetal body and liver weight and thorax circumference on 5mC content of liver DNA were positive (P < 0.073-0.079). Furthermore, a significant negative regression (P < 0.021) of the crown-rump length:thorax circumference ratio on liver 5mC was observed. The 5mC content of placental cotyledon DNA was 46% lower than in liver DNA (P < 0.0001) but did not differ among groups. These data are in striking contrast with the recently reported hypomethylation of DNA from SCNT fetuses and indicate that hypermethylation of fetal tissue, but not placenta, is linked to the overgrowth phenotype in bovine SCNT and IVF fetuses.