CGGBP1 is a repeat-binding protein with diverse functions in the regulation of gene expression, cytosine methylation, repeat silencing and genomic integrity. CGGBP1 has also been identified as a cooperator of histone-modifying enzymes and as a component of CTCF-containing complexes that regulate the enhancer–promoter looping. CGGBP1–CTCF cross talk in chromatin regulation has been hitherto unknown. Here, we report that the occupancy of CTCF at repeats depends on CGGBP1. Using ChIP-sequencing for CTCF, we describe its occupancy at repetitive DNA. Our results show that endogenous level of CGGBP1 ensures CTCF occupancy preferentially on repeats over canonical CTCF motifs. By combining CTCF ChIP-sequencing results with ChIP sequencing for three different kinds of histone modifications (H3K4me3, H3K9me3 and H3K27me3), we show that the CGGBP1-dependent repeat-rich CTCF-binding sites regulate histone marks in flanking regions. CGGBP1 affects the pattern of CTCF occupancy. Our results posit CGGBP1 as a regulator of CTCF and its binding sites in interspersed repeats.

中文翻译：

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CGGBP1重复调节CTCF的占用。

CGGBP1是一种重复结合蛋白，在调节基因表达，胞嘧啶甲基化，重复沉默和基因组完整性方面具有多种功能。CGGBP1还被认为是组蛋白修饰酶的合作者，并且是含有CTCF的复合物的组成部分，该复合物可调节增强子-启动子环。迄今为止，在染色质调节中的CGGBP1–CTCF串扰是未知的。在这里，我们报告重复的CTCF占用取决于CGGBP1。使用CTIP的ChIP测序，我们描述了其在重复DNA上的占有率。我们的结果表明，内源性CGGBP1水平可确保CTCF在重复序列上的占有率优先于规范CTCF基序。通过将CTCF ChIP测序结果与ChIP测序相结合，可用于三种不同类型的组蛋白修饰（H3K4me3，H3K9me3和H3K27me3），我们表明依赖CGGBP1的重复丰富的CTCF结合位点调节侧翼区域中的组蛋白标记。CGGBP1影响CTCF的占用模式。我们的结果假定CGGBP1作为CTCF及其散布重复序列中的结合位点的调节剂。