A BRD4-mediated elongation control point primes transcribing RNA polymerase II for 3'-processing and termination [ChIP-seq]. A BRD4-mediated elongation control point primes transcribing RNA polymerase II for 3'-processing and termination [ChIP-seq]

In this study, we reveal that BRD4 underlies a general 5'-elongation checkpoint that primes transcribing RNA polymerase II for 3'-RNA processing and transcription termination. BRD4-specific degradation impairs Pol II pause release, induces massive readthrough transcription, and RNA cleavage defects. Acute loss of BRD4 disrupts the recruitment of 3'-RNA processing factors. Overall design: ChIP-Rx measurements for Pol II, Pol II Ser2-P, SPT5, PAF1, FIP1, CPSF73 and CstF64 upon DMSO (control) and dTAG7 (BRD4 degradation) treatment in K562 dTAG-BRD4 cells (two biological replicate measurements and matched input controls for each condition).

本研究揭示，BRD4介导了一类通用的5'端延伸检查点，可使正在转录的RNA聚合酶II（RNA polymerase II）为3'端RNA加工与转录终止做好准备。特异性降解BRD4会削弱Pol II的暂停释放过程，诱导大规模通读转录，并引发RNA切割缺陷。BRD4的急性缺失会破坏3'端RNA加工因子的招募。实验设计概述：在K562 dTAG-BRD4细胞中，分别以二甲基亚砜（DMSO，对照组）与dTAG7（诱导BRD4降解）处理后，针对Pol II、Ser2磷酸化Pol II（Pol II Ser2-P）、SPT5、PAF1、FIP1、CPSF73及CstF64开展ChIP-Rx检测；每个处理组均设置两次生物学重复及匹配的输入对照。