Epigenetic and genomic imprinting analysis in nuclear transfer derived Bos gaurus/Bos taurus hybrid fetuses
Epigenetic and genomic imprinting analysis in nuclear transfer derived Bos gaurus/Bos taurus hybrid fetuses
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DOI：
10.1095/biolreprod.103.025775
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发表时间：
2004-08-01
影响因子：
3.6
通讯作者：
Piedrahita, JA
中科院分区：
文献类型：
--
作者：
Dindot, SV;Farin, PW;Piedrahita, JA
牛的体细胞核移植（NT）是一个效率低下的过程，由此小牛的生产受到低妊娠率以及胎儿和胎盘异常的阻碍。种间模型先前已被用于促进基因编码区内的单核苷酸多态性（SNP）的鉴定，以区分后代中的亲本等位基因。在这里，我们报告使用牛种间模型（Bos gaurus x Bos taurus）的表观遗传修饰和基因组印记的评估和表征在第40天的女性NT衍生的胎儿和胎盘。NT和对照妊娠的分析表明，在X失活特异性转录（XIST）位点的绒毛膜，但不是克隆胎儿的基因组印迹中断，而适当的等位基因表达的胰岛素样生长因子II（IGF 2）和基因陷阱位点2（GTL 2）位点保持在胎儿和胎盘。克隆中XIST差异甲基化区域（DMR）的分析表明甲基化的正常模式，然而，卫星I重复元件和表皮细胞角蛋白启动子的亚硫酸氢盐测序表明与对照相比，克隆的绒毛膜中的超甲基化。在胎儿中未检测到甲基化水平的差异。这些结果表明，核转移过程中的滋养外胚层和内细胞团来源的组织中的基因表达模式的影响在不同程度上。
Somatic cell nuclear transfer (NT) in cattle is an inefficient process, whereby the production of calves is hindered by low pregnancy rates as well as fetal and placental abnormalities. Interspecies models have been previously used to facilitate the identification of single nucleotide polymorphisms (SNPs) within coding regions of genes to discriminate between parental alleles in the offspring. Here we report the use of a bovine interspecies model (Bos gaurus x Bos taurus) for the assessment and characterization of epigenetic modifications and genomic imprinting in Day 40-old female NT-derived fetuses and placenta. Analysis of NT and control pregnancies indicated disruption of genomic imprinting at the X inactivation-specific transcript (XIST) locus in the chorion, but not the fetus of clones, whereas proper allelic expression of the insulin-like growth factor II (IGF2) and gene trap locus 2 (GTL2) loci was maintained in both the fetus and placenta. Analysis of the XIST differentially methylated region (DMR) in clones indicated normal patterns of methylation; however, bisulfite sequencing of the satellite I repeat element and epidermal cytokeratin promoter indicated hypermethylation in the chorion of clones when compared with controls. No differences were detected in methylation levels in the fetus proper. These results indicate that the nuclear transfer process affects gene expression patterns in the trophectoderm- and inner cell mass-derived tissues to different extents.