Differential recruitment of methylated CpG binding domains by the orphan receptor GCNF initiates the repression and silencing of Oct4 expression (Retracted article. See vol. 29, pg. 1987, 2009)
Differential recruitment of methylated CpG binding domains by the orphan receptor GCNF initiates the repression and silencing of Oct4 expression (Retracted article. See vol. 29, pg. 1987, 2009)
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DOI：
10.1128/mcb.00898-06
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发表时间：
2006-12-01
影响因子：
5.3
通讯作者：
Cooney, Austin J.
中科院分区：
文献类型：
--
作者：
Gu, Peili;Le Menuet, Damien;Cooney, Austin J.
多能因子Oct 4是维持胚胎干细胞自我更新的关键转录因子，在胚胎干细胞分化时下调，在体细胞中沉默。顺式元件、转录因子和表观遗传修饰（如DNA甲基化）的组合参与Oct 4基因表达的调节。在这里，我们表明，孤儿核受体GCNF启动Oct 4阻遏和DNA甲基化的差异招聘MBD（甲基化CpG结合域）的启动子因子。与野生型ES细胞和原肠胚相比，RA分化的GCNF（-/-）ES细胞中Oct 4阻遏消失，其近端启动子显著低甲基化。Oct 4基因在GCNF（-/-）胚胎的一些体细胞中重新表达，表明它没有被适当地沉默，同时其启动子的DNA甲基化降低。对GCNF的抑制功能和Oct 4启动子的DNA甲基化的介体的表征工作确定了甲基DNA结合蛋白MBD 3和MBD 2为GCNF相互作用因子。在P19和ES细胞中，在分化时，内源性GCNF与Oct 4近端启动子结合，并差异性地募集MBD 3和MBD 2。在分化的GCNF（-/-）ES细胞中，MBD 3和MBD 2向Oct 4启动子的募集丢失，并且不能发生Oct 4表达和DNA甲基化的抑制。RNA干扰介导的MBD 3和/或MBD 2表达的敲低导致分化的P19和ES细胞中Oct 4抑制减少。Oct 4表达的抑制和MBD 3的募集在从头DNA甲基化缺陷的ES细胞（Dnmt 3A/3B缺失细胞）中得以维持，而MBD 2募集丧失。因此，GCNF对MBD 3和MBD 2的募集将基因特异性抑制和DNA甲基化这两个事件联系起来，这两个事件在Oct 4启动子处发生差异。GCNF在ES细胞分化过程中启动Oct 4基因的阻遏和表观遗传修饰。
The pluripotent factor Oct4 is a key transcription factor that maintains embryonic stem (ES) cell self-renewal and is down-regulated upon the differentiation of ES cells and silenced in somatic cells. A combination of cis elements, transcription factors, and epigenetic modifications, such as DNA methylation, are involved in the regulation of Oct4 gene expression. Here we show that the orphan nuclear receptor GCNF initiates Oct4 repression and DNA methylation by the differential recruitment of MBD (methylated CpG binding domain) factors to the promoter. Compared with wild-type ES cells and gastrulating embryos, Oct4 repression is lost and its proximal promoter is significantly hypomethylated in RA-differentiated GCNF(-/-) ES cells. The Oct4 gene is reexpressed in some somatic cells of GCNF(-/-) embryos, showing that it has not been properly silenced coincident with reduced DNA methylation of its promoter. Efforts to characterize mediators of GCNF's repressive function and DNA methylation of the Oct4 promoter identified methyl-DNA binding proteins, MBD3 and MBD2, as GCNF-interacting factors. In P19 and ES cells, upon differentiation, endogenous GCNF binds to the Oct4 proximal promoter and differentially recruits MBD3 and MBD2. In differentiated GCNF(-/-) ES cells, recruitment of MBD3 and MBD2 to the Oct4 promoter is lost, and repression of Oct4 expression and DNA methylation fails to occur. RNA interference-mediated knockdown of MBD3 and/or MBD2 expression results in reduced Oct4 repression in differentiated P19 and ES cells. Repression of Oct4 expression and recruitment of MBD3 are maintained in de novo DNA methylation-deficient ES cells (Dnmt3A/3B-null cells), while MBD2 recruitment is lost. Thus, recruitment of MBD3 and MBD2 by GCNF links two events, gene-specific repression and DNA methylation, which occur differentially at the Oct4 promoter. GCNF initiates the repression and epigenetic modification of Oct4 gene during ES cell differentiation.