DNA Methylation Is Dispensable for the Growth and Survival of the Extraembryonic Lineages
DNA Methylation Is Dispensable for the Growth and Survival of the Extraembryonic Lineages
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DOI：
10.1016/j.cub.2010.06.050
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发表时间：
2010-08-24
期刊：
影响因子：
9.2
通讯作者：
Okano, Masaki
中科院分区：
文献类型：
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作者：
Sakaue, Morito;Ohta, Hiroshi;Okano, Masaki
DNA甲基化调节哺乳动物的发育和许多表观遗传过程[1]，并且它是体细胞生长和存活所必需的[2，3]。相比之下，胚胎干细胞（ES）可以自我更新而无需DNA甲基化[4-6]。目前尚不清楚是否有任何谱系定型细胞可以在没有DNA甲基化机制的情况下存活。与体细胞不同，DNA甲基化是胚胎外谱系中印记和X失活的关键[7-12]。在ES细胞中，DNA甲基化阻止分化为滋养外胚层命运[13]。在这里，我们通过核移植（NT）创建了缺乏活性DNA甲基转移酶Dnmt 1，Dnmt 3a和Dnmt 3b（TKO）的三重敲除（TKO）小鼠胚胎，并检查了它们的发育。在嵌合TKO-NT和WT胚胎中，在胚胎中发现很少TKO细胞，但它们有助于胚外组织。TKO ES细胞在分化成上胚层谱系期间显示出增加的细胞死亡，但在分化成胚外谱系期间没有。此外，我们成功地建立了滋养层干细胞（ntTS细胞）从TKO-NT囊胚。这些TKO ntTS细胞可以自我更新，并且它们保留了干细胞的基本基因表达模式。我们的研究结果表明，胚胎外谱系细胞可以在DNA甲基转移酶的情况下生存和增殖，细胞对表观基因组损伤应激的反应是细胞类型依赖性的。
DNA methylation regulates development and many epigenetic processes in mammals [1], and it is required for somatic cell growth and survival [2, 3]. In contrast, embryonic stem (ES) cells can self-renew without DNA methylation [4-6]. It remains unclear whether any lineage-committed cells can survive without DNA-methylation machineries. Unlike in somatic cells, DNA methylation is dispensable for imprinting and X-inactivation in the extraembryonic lineages [7-12]. In ES cells, DNA methylation prevents differentiation into the trophectodermal fate [13]. Here, we created triple-knockout (TKO) mouse embryos deficient for the active DNA methyltransferases Dnmt1, Dnmt3a, and Dnmt3b (TKO) by nuclear transfer (NT), and we examined their development. In chimeric TKO-NT and WT embryos, few TKO cells were found in the embryo proper, but they contributed to extraembryonic tissues. TKO ES cells showed increasing cell death during their differentiation into epiblast lineages, but not during differentiation into extraembryonic lineages. Furthermore, we successfully established trophoblastic stem cells (ntTS cells) from TKO-NT blastocysts. These TKO ntTS cells could self-renew, and they retained the fundamental gene expression patterns of stem cells. Our findings indicated that extraembryonic-lineage cells can survive and proliferate in the absence of DNA methyltransferases and that a cell's response to the stress of epigenomic damage is cell type dependent.