Department of Pathology, New York University School of Medicine, New York, New York, USA.
Department of Molecular Biology, Massachusetts General Hospital, Boston, Massachusetts, USA; Department of Genetics, Harvard Medical School, Boston, Massachusetts, USA.
J Biol Chem. 2021 Jan-Jun;296:100170. doi: 10.1074/jbc.RA120.015876. Epub 2020 Dec 13.
Elongin is an RNA polymerase II (RNAPII)-associated factor that has been shown to stimulate transcriptional elongation in vitro. The Elongin complex is thought to be required for transcriptional induction in response to cellular stimuli and to ubiquitinate RNAPII in response to DNA damage. Yet, the impact of the Elongin complex on transcription in vivo has not been well studied. Here, we performed comprehensive studies of the role of Elongin A, the largest subunit of the Elongin complex, on RNAPII transcription genome-wide. Our results suggest that Elongin A localizes to actively transcribed regions and potential enhancers, and the level of recruitment correlated with transcription levels. We also identified a large group of factors involved in transcription as Elongin A-associated factors. In addition, we found that loss of Elongin A leads to dramatically reduced levels of serine2-phosphorylated, but not total, RNAPII, and cells depleted of Elongin A show stronger promoter RNAPII pausing, suggesting that Elongin A may be involved in the release of paused RNAPII. Our RNA-seq studies suggest that loss of Elongin A did not alter global transcription, and unlike prior in vitro studies, we did not observe a dramatic impact on RNAPII elongation rates in our cell-based nascent RNA-seq experiments upon Elongin A depletion. Taken together, our studies provide the first comprehensive analysis of the role of Elongin A in regulating transcription in vivo. Our studies also revealed that unlike prior in vitro findings, depletion of Elongin A has little impact on global transcription profiles and transcription elongation in vivo.
elongin 是一种 RNA 聚合酶 II（RNAPII）相关因子，已被证明可在体外刺激转录延伸。 elongin 复合物被认为是细胞刺激反应中转录诱导所必需的，并且可响应 DNA 损伤泛素化 RNAPII。然而， elongin 复合物对体内转录的影响尚未得到很好的研究。在这里，我们对 elongin A（elongin 复合物的最大亚基）在全基因组范围内对 RNAPII 转录的作用进行了全面研究。我们的结果表明， elongin A 定位于活跃转录区域和潜在增强子，募集水平与转录水平相关。我们还鉴定了一大组参与转录的因子作为 elongin A 相关因子。此外，我们发现 elongin A 的缺失导致丝氨酸 2 磷酸化的，但不是总，RNAPII 的水平显著降低，并且耗尽 elongin A 的细胞显示更强的启动子 RNAPII 暂停，表明 elongin A 可能参与暂停的 RNAPII 的释放。我们的 RNA-seq 研究表明，eloin A 的缺失并没有改变全局转录，并且与之前的体外研究不同，我们在基于细胞的新生 RNA-seq 实验中没有观察到 elongin A 耗尽后 RNAPII 延伸率的显著影响。总之，我们的研究提供了 elongin A 在调节体内转录中的作用的首次全面分析。我们的研究还表明，与之前的体外发现不同，eloin A 的耗尽对体内全局转录谱和转录延伸几乎没有影响。
