Deng Tao, Kuang Ying, Zhang Dan, Wang Long, Sun Ruilin, Xu Guojiang, Wang Zhugang, Fei Jian
Laboratory of Molecular Cell Biology, Institute of Biochemistry and Cell Biology and Model Organism Research Center, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China.
Dev Growth Differ. 2007 Sep;49(7):603-10. doi: 10.1111/j.1440-169X.2007.00955.x. Epub 2007 Jul 17.
The completely embryonic stem (ES) cell-derived mice (ES mice) produced by tetraploid embryo complementation provide us with a rapid and powerful approach for functional genome analysis. However, inbred ES cell lines often fail to generate ES mice. The genome of mouse ES cells is extremely unstable during in vitro culture and passage, and the expression of the imprinted genes is most likely to be affected. Whether the ES mice retain or repair the abnormalities of the donor ES cells has still to be determined. Here we report that the inbred ES mice were efficiently produced with the inbred ES cell line (SCR012). The ES fetuses grew more slowly before day 17.5 after mating, but had an excessive growth from day 17.5 to birth. Five imprinted genes examined (H19, Igf2, Igf2r, Peg1, Peg3) were expressed abnormally in ES fetuses. Most remarkably, the expression of H19 was dramatically repressed in the ES fetuses through the embryo developmental stage, and this repression was associated with abnormal biallelic methylation of the H19 upstream region. The altered methylation pattern of H19 was further demonstrated to have arisen in the donor ES cells and persisted on in vivo differentiation to the fetal stage. These results indicate that the ES fetuses did retain the epigenetic alterations in imprinted genes from the donor ES cells.
通过四倍体胚胎互补技术产生的完全由胚胎干细胞（ES细胞）衍生而来的小鼠（ES小鼠），为我们提供了一种快速且强大的功能基因组分析方法。然而，近交ES细胞系常常无法产生ES小鼠。小鼠ES细胞的基因组在体外培养和传代过程中极其不稳定，印记基因的表达很可能受到影响。ES小鼠是否保留或修复了供体ES细胞的异常情况仍有待确定。在此我们报告，利用近交ES细胞系（SCR012）高效产生了近交ES小鼠。ES胎儿在交配后17.5天之前生长较为缓慢，但从17.5天到出生则过度生长。所检测的五个印记基因（H19、Igf2、Igf2r、Peg1、Peg3）在ES胎儿中表达异常。最显著的是，H19的表达在ES胎儿整个胚胎发育阶段都受到显著抑制，且这种抑制与H19上游区域异常的双等位基因甲基化有关。H19甲基化模式的改变进一步证明是在供体ES细胞中出现的，并在体内分化至胎儿阶段时持续存在。这些结果表明，ES胎儿确实保留了来自供体ES细胞的印记基因的表观遗传改变。
