DNA甲基化状态及组蛋白乙酰化水平影响克隆胚胎再程序化过程，组蛋白甲基化与DNA甲基化密切相关，三甲基组蛋白3赖氨酸9（H3K9me3）甲基化程度最高，是最难以重构化的表观遗传标记之一，而JMJD2B基因是一种特异性H3K9Me3去甲基化酶。本研究拟构建功能性及突变体JMJD2B-EGFP表达载体，及结合siRNA技术在牛成纤维细胞中过量或沉默JMJD2B基因表达，并检测功能性及突变体JMJD2B过表达，JMJD2B沉默后成纤维细胞基因组甲基化水平，Oct4基因启动子甲基化水平，H3K9me3及组蛋白乙酰化（AcH3K9，AcH4K5）水平、并检测JMJD2B过表细胞构建重组早期胚胎H3K9me3及全能性相关基因Oct4基因表达水平，探讨JMJD2B过表达及沉默表达后、H3K9me3去甲基化及组蛋白乙酰化间的相关性，及其对核移植重组胚胎发育全能性重塑的影响。

The status of DNA methylation and histone acetylation affect the reprogramming of SCNT nucleus, the status of histone methylation is closely associated to the DNA methylation levels, H3K9me3 is one of the highest forms of histone methylation ,and also it is one ofthe hardest epigenetic markers to remove during the reprogramming of SCNT nucleus.As we know that the JMJD2B gene is one type of specific demethylase have effect on the demethylation of H3K9me3.In this studies, we try to construct two kinds of the functional and mutant JMJD2B gene expression vectors,through flp-in system,the inducible functional and mutant JMJD2B-EGFP gene was overexpression in these cells,and combined with the siRNA technique to knockout JMJD2B gene mRNA expression,through these methods,we try to quantify the DNA methylation levels of global genomic DNA,methylation levels of Oct4 gene promotor area and H3K9me3 levels and histone acetylation levels in bovine fibroblast cells respectively.As results, we can systemly to discuss the relationship between overexpression and knockout of JMJD2B gene and the regulation of H3K9me3 and Histone acetylation in fibroblast cells, and also study the effects of overexpression of JMJD2B gene on the demethylation of H3K9me3 and expression levels of pluripotency related genes like Oct4, of cloned embryos,which can contribute to further study the mechanism of nucleus reprogramming.