Vigilin interacts with CCCTC-binding factor (CTCF) and is involved in CTCF-dependent regulation of the imprinted genes Igf2 and H19
Vigilin interacts with CCCTC-binding factor (CTCF) and is involved in CTCF-dependent regulation of the imprinted genes Igf2 and H19
复制标题
Vigilin 与 CCCTC 结合因子 (CTCF) 相互作用，并参与印迹基因 Igf2 和 H19 的 CTCF 依赖性调节
DOI：
10.1111/febs.12816
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发表时间：
2014-06-01
期刊：
影响因子：
5.4
通讯作者：
Qin, Yang
中科院分区：
文献类型：
--
作者：
Liu, Qiuying;Yang, Bo;Qin, Yang
CCCTC结合因子（CCCTC binding factor，CTCF）是一种高度保守的锌指蛋白，是基因组空间组织的主要组织者，具有多种基因调控功能。越来越多的证据表明，CTCF调节印迹基因Igf 2和H19的组织染色质在Igf 2/H19位点，虽然CTCF进行这种功能的机制还没有完全理解。通过酵母双杂交筛选，我们确定了一个多KH结构域蛋白vigilin作为CTCF的新伴侣。随后的免疫共沉淀和谷胱甘肽S-转移酶下拉实验证实，vigilin与CTCF相互作用。此外，Vigilin存在于几个已知的CTCF靶位点，如c-myc和BRCA 1的启动子区、β-珠蛋白的基因座控制区和Igf 2/H19基因座内的几个区域。在体内消耗vigilin不影响CTCF结合，但是，敲低CTCF减少vigilin结合到H19印迹控制区。此外，在HepG 2，CNE 1和HeLa细胞中，vigilin的异位表达显著下调Igf 2和上调H19，而vigilin的缺失上调Igf 2和下调H19。这些结果揭示了Vigilin和CTCF的功能相关性，并表明CTCF-Vigilin复合物有助于Igf 2/H19的调节。
CCCTC-binding factor (CTCF), a highly conserved zinc finger protein, is a master organizer of genome spatial organization and has multiple functions in gene regulation. Mounting evidence indicates that CTCF regulates the imprinted genes Igf2 and H19 by organizing chromatin at the Igf2/H19 locus, although the mechanism by which CTCF carries out this function is not fully understood. By yeast two-hybrid screening, we identified vigilin, a multi-KH-domain protein, as a new partner of CTCF. Subsequent coimmunoprecipitation and glutathione S-transferase pulldown experiments confirmed that vigilin interacts with CTCF. Moreover, vigilin is present at several known CTCF target sites, such as the promoter regions of c-myc and BRCA1, the locus control region of beta-globin, and several regions within the Igf2/H19 locus. In vivo depletion of vigilin did not affect CTCF binding; however, knockdown of CTCF reduced vigilin binding to the H19 imprinting control region. Furthermore, ectopic expression of vigilin significantly downregulated Igf2 and upregulated H19, whereas depletion of vigilin upregulated Igf2 and downregulated H19, in HepG2, CNE1 and HeLa cells. These results reveal the functional relevance of vigilin and CTCF, and show that the CTCF-vigilin complex contributes to regulation of Igf2/H19.