Functional interactions of RNA-capping enzyme with factors that positively and negatively regulate promoter escape by RNA polymerase II
Functional interactions of RNA-capping enzyme with factors that positively and negatively regulate promoter escape by RNA polymerase II
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DOI：
10.1073/pnas.0401493101
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发表时间：
2004-05-18
影响因子：
11.1
通讯作者：
Reinberg, D
中科院分区：
文献类型：
--
作者：
Mandal, SS;Chu, C;Reinberg, D
新生 RNA 聚合酶 II 转录物 5' 末端的加帽是所有真核细胞中的第一个前 mRNA 加工事件。通过 RNA 聚合酶 II 最大亚基羧基末端结构域 Ser-5 的磷酸化启动后，加帽酶 (CE) 很快被招募到转录复合物中。在这里，我们分析了 CE 在启动子清除中的作用及其与启动子清除中涉及的不同因素的功能相互作用。 FCP1 介导的羧基末端结构域去磷酸化导致共转录加帽效率急剧下降，但 DRB 敏感性诱导因子 (DSIF) 的存在可以逆转这种情况。这些结果表明 DSIF 参与了 CE 招募。重要的是，CE 可减轻负延伸因子的转录抑制，表明 CE 在启动子清除过程中的延伸检查点控制机制中发挥着关键作用。 CE 和负延伸因子之间的这种功能性相互作用证明了 CE 在启动子清除中的动态作用超出了其催化活性。
Capping of the 5' ends of nascent RNA polymerase II transcripts is the first pre-mRNA processing event in all eukaryotic cells. Capping enzyme (CE) is recruited to transcription complexes soon after initiation by the phosphorylation of Ser-5 of the carboxyl-terminal domain of the largest subunit of RNA polymerase II. Here, we analyze the role of CE in promoter clearance and its functional interactions with different factors that are involved in promoter clearance. FCP1-mediated dephosphorylation of the carboxyl-terminal domain results in a drastic decrease in cotranscriptional capping efficiency but is reversed by the presence of DRB sensitivity-inducing factor (DSIF). These results suggest involvement of DSIF in CE recruitment. Importantly, CE relieves transcriptional repression by the negative elongation factor, indicating a critical role of CE in the elongation checkpoint control mechanism during promoter clearance. This functional interaction between CE and the negative elongation factor documents a dynamic role of CE in promoter clearance beyond its catalytic activities.