Genomic Medicine Institute, Lerner Research Institute, Cleveland Clinic, Cleveland, OH, USA.
Taussig Cancer Institute, Cleveland Clinic, Cleveland, OH, USA.
Hum Mol Genet. 2019 Sep 1;28(17):2826-2834. doi: 10.1093/hmg/ddz112.
Control of gene expression is one of the most complex yet continuous physiological processes impacting cellular homeostasis. RNA polymerase II (Pol II) transcription is tightly regulated at promoter-proximal regions by intricate dynamic processes including Pol II pausing, release into elongation and premature termination. Pol II pausing is a phenomenon where Pol II complex pauses within 30-60 nucleotides after initiating the transcription. Negative elongation factor (NELF) and DRB sensitivity inducing factor (DSIF) contribute in the establishment of Pol II pausing, and positive transcription elongation factor b releases (P-TEFb) paused complex after phosphorylating DSIF that leads to dissociation of NELF. Pol II pausing is observed in most expressed genes across the metazoan. The precise role of Pol II pausing is not well understood; however, it's required for integration of signals for gene regulation. In the present study, we investigated the role of phosphatase and tensin homolog (PTEN) in genome-wide transcriptional regulation using PTEN overexpression and PTEN knock-down models. Here we identify that PTEN alters the expression of hundreds of genes, and its restoration establishes genome-wide Pol II promoter-proximal pausing in PTEN null cells. Furthermore, PTEN re-distributes Pol II occupancy across the genome and possibly impacts Pol II pause duration, release and elongation rate in order to enable precise gene regulation at the genome-wide scale. Our observations demonstrate an imperative role of PTEN in global transcriptional regulation that will provide a new direction to understand PTEN-associated pathologies and its management.
基因表达的控制是影响细胞内稳态的最复杂但又是持续不断的生理过程之一。RNA 聚合酶 II(Pol II)转录在启动子近端区域受到复杂的动态过程的严格调节,包括 Pol II 暂停、进入延伸和过早终止的释放。Pol II 暂停是 Pol II 复合物在起始转录后 30-60 个核苷酸内暂停的现象。负延伸因子(NELF)和 DRB 敏感性诱导因子(DSIF)有助于 Pol II 暂停的建立,而磷酸化 DSIF 后释放的正转录延伸因子 b(P-TEFb)会使 NELF 解离,从而使暂停复合物释放。Pol II 暂停在大多数后生动物的表达基因中都观察到。Pol II 暂停的确切作用尚不清楚;然而,它是基因调控信号整合所必需的。在本研究中,我们使用 PTEN 过表达和 PTEN 敲低模型研究了磷酸酶和张力蛋白同源物(PTEN)在全基因组转录调控中的作用。在这里,我们确定了 PTEN 改变了数百个基因的表达,其恢复在 PTEN 缺失细胞中建立了全基因组 Pol II 启动子近端暂停。此外,PTEN 在整个基因组中重新分配 Pol II 占据,并可能影响 Pol II 暂停持续时间、释放和延伸率,以在全基因组范围内实现精确的基因调控。我们的观察表明,PTEN 在全局转录调控中起着至关重要的作用,这将为理解与 PTEN 相关的病理学及其管理提供新的方向。
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