CTCFL/BORIS is a methylation-independent DNA-binding protein that preferentially binds to the paternal H19 differentially methylated region.
CTCFL/BORIS is a methylation-independent DNA-binding protein that preferentially binds to the paternal H19 differentially methylated region.
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CTCFL/BORIS是一种与甲基化无关的DNA结合蛋白，优先结合父亲H19差异甲基化区域。
DOI：
10.1158/0008-5472.can-08-1005
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发表时间：
2008-07-15
期刊：
影响因子：
11.2
通讯作者：
Gius D
中科院分区：
文献类型：
--
作者：
Nguyen P;Cui H;Bisht KS;Sun L;Patel K;Lee RS;Kugoh H;Oshimura M;Feinberg AP;Gius D
CTCF paraminoboris（印记位点调节器的兄弟）是一种绝缘体DNA结合蛋白，被认为在染色质组织和基因表达中发挥作用。在正常生理条件下，BORIS主要在胚胎雄性生殖细胞发育期间表达;然而，它也在肿瘤和肿瘤细胞系中表达，因此，已被分类为癌-生殖系或癌-睾丸基因。有人认为BORIS可能是一个促增殖因子，而CTCF有利于抗增殖。BORIS和CTCF具有相似的锌指DNA结合结构域，似乎与相同的靶序列结合。因此，一个关键的问题是当这两种蛋白质都存在于肿瘤细胞中时，控制这两种蛋白质的DNA结合特异性的机制。染色质免疫沉淀（ChIP）在HCT 116细胞和他们的高甲基化的变体表明，BORIS结合甲基化的DNA序列，而CTCF结合非甲基化的DNA。使用全细胞提取物和体外翻译的CTCF和BORIS蛋白的电迁移率变化测定以及甲基化特异性ChIP PCR表明，BORIS是一种甲基化非依赖性DNA结合蛋白。最后，在含有母本或父本人类11号染色体的鼠杂交细胞中的实验表明，BORIS优先结合甲基化的父本H19差异甲基化区域，表明CTCF对未甲基化的母本等位基因的亲和力指导BORIS与父本等位基因的DNA结合的机制。
The CTCF paralog BORIS (brother of the regulator of imprinted sites) is an insulator DNA-binding protein thought to play a role in chromatin organization and gene expression. Under normal physiologic conditions, BORIS is predominantly expressed during embryonic male germ cell development; however, it is also expressed in tumors and tumor cell lines and, as such, has been classified as a cancer-germline or cancer-testis gene. It has been suggested that BORIS may be a pro-proliferative factor, whereas CTCF favors antiproliferation. BORIS and CTCF share similar zinc finger DNA-binding domains and seem to bind to identical target sequences. Thus, one critical question is the mechanism governing the DNA-binding specificity of these two proteins when both are present in tumor cells. Chromatin immunoprecipitation (ChIP) in HCT116 cells and their hypermethylated variant showed that BORIS binds to methylated DNA sequences, whereas CTCF binds to unmethylated DNA. Electromobility shift assays, using both whole-cell extracts and in vitro translated CTCF and BORIS protein, and methylation-specific ChIP PCR showed that BORIS is a methylation-independent DNA-binding protein. Finally, experiments in murine hybrid cells containing either the maternal or paternal human chromosome 11 showed that BORIS preferentially binds to the methylated paternal H19 differentially methylated region, suggesting a mechanism in which the affinity of CTCF for the unmethylated maternal allele directs the DNA binding of BORIS toward the paternal allele.