Genome-wide analysis of Groucho in Drosophila Kc167 and S2R+ cell lines

In this study we have used ChIP followed by high throughput sequencing to profile the genome-wide recruitment of wildtype and non-oligomerizing Groucho (Gro) at high resolution in single cell types (Kc167 and S2R+) using Drosophila cell culture. Our results reveal that Gro is typically recruited to discrete peaks in active chromatin and that blocking Gro oligomerization does not change the width of the peaks to which it is recruited. We have also investigated acetylated histone H3 and H4 and RNA polymerase II profiles around Gro binding sites, along with gene expression, in wildtype and Gro knockdown Kc167 cells and found that Gro associates with chromatin containing hypoacetylated histones and frequently overlaps the transcription start sites of expressed genes that exhibit strong RNA polymerase pausing.

本研究采用染色质免疫共沉淀（ChIP）结合高通量测序（high throughput sequencing）技术，以果蝇细胞培养体系中的单一细胞类型（Kc167与S2R+）为研究对象，以高分辨率绘制了野生型与非寡聚化格鲁乔（Groucho, Gro）的全基因组招募图谱。研究结果表明，格鲁乔通常会被招募至活性染色质上的离散结合峰区域，且阻断格鲁乔的寡聚化并不会改变其招募结合峰的宽度。本研究同时针对野生型与格鲁乔敲低的Kc167细胞，分析了格鲁乔结合位点周围的乙酰化组蛋白H3、H4以及RNA聚合酶II（RNA polymerase II）的分布特征，并结合基因表达数据开展联合分析，结果发现格鲁乔可与携带低乙酰化组蛋白修饰的染色质相结合，且其结合位点常与存在显著RNA聚合酶暂停（RNA polymerase pausing）的表达基因的转录起始位点（transcription start sites）存在重叠。