PDF(Pubmed)
Abstract：
Enhancer-gene communication is dependent on topologically associating domains (TADs) and boundaries enforced by the CCCTC-binding factor (CTCF) insulator, but the underlying structures and mechanisms remain controversial. Here, we investigate a boundary that typically insulates fibroblast growth factor (FGF) oncogenes but is disrupted by DNA hypermethylation in gastrointestinal stromal tumors (GISTs). The boundary contains an array of CTCF sites that enforce adjacent TADs, one containing FGF genes and the other containing ANO1 and its putative enhancers, which are specifically active in GIST and its likely cell of origin. We show that coordinate disruption of four CTCF motifs in the boundary fuses the adjacent TADs, allows the ANO1 enhancer to contact FGF3, and causes its robust induction. High-resolution micro-C maps reveal specific contact between transcription initiation sites in the ANO1 enhancer and FGF3 promoter that quantitatively scales with FGF3 induction such that modest changes in contact frequency result in strong changes in expression, consistent with a causal relationship.
摘要：
增强子-基因通讯取决于拓扑关联域（TAD）和由CCCTC结合因子（CTCF）绝缘体强制执行的边界，但是潜在的结构和机制仍然存在争议。这里,我们研究了在胃肠道间质瘤(GIST)中通常隔离成纤维细胞生长因子(FGF)癌基因但被DNA甲基化破坏的边界.边界包含一组CTCF站点，这些站点强制相邻的TAD，一个含有FGF基因，另一个含有ANO1及其推定的增强子，在GIST及其可能的起源细胞中特别活跃。我们表明，边界中四个CTCF基序的坐标破坏会融合相邻的TAD，允许ANO1增强子接触FGF3，并引起其强大的诱导。高分辨率micro-C图谱揭示了ANO1增强子和FGF3启动子中转录起始位点之间的特定接触，该启动子与FGF3诱导定量缩放，从而使接触频率的适度变化导致表达的强烈变化。符合因果关系。
