The Rockefeller University, New York, NY 10065, USA.
Cell. 2010 Feb 19;140(4):491-503. doi: 10.1016/j.cell.2009.12.050.
Genetic and cell-based studies have implicated the PAF1 complex (PAF1C) in transcription-associated events, but there has been no evidence showing a direct role in facilitating transcription of a natural chromatin template. Here, we demonstrate an intrinsic ability of human PAF1C (hPAF1C) to facilitate activator (p53)- and histone acetyltransferase (p300)-dependent transcription elongation from a recombinant chromatin template in a biochemically defined RNA polymerase II transcription system. This represents a PAF1C function distinct from its established role in histone ubiquitylation and methylation. Importantly, we further demonstrate a strong synergy between hPAF1C and elongation factor SII/TFIIS and an underlying mechanism involving direct hPAF1C-SII interactions and cooperative binding to RNA polymerase II. Apart from a distinct PAF1C function, the present observations provide a molecular mechanism for the cooperative function of distinct transcription elongation factors in chromatin transcription.
遗传和基于细胞的研究表明 PAF1 复合物（PAF1C）参与转录相关事件，但没有证据表明其在促进天然染色质模板转录中具有直接作用。在这里，我们证明了人源 PAF1C（hPAF1C）在生化定义的 RNA 聚合酶 II 转录系统中从重组染色质模板上促进激活剂（p53）和组蛋白乙酰转移酶（p300）依赖性转录延伸的内在能力。这代表了 PAF1C 的一种不同于其在组蛋白泛素化和甲基化中已有作用的功能。重要的是，我们进一步证明了 hPAF1C 与延伸因子 SII/TFIIS 之间存在强烈的协同作用，其潜在机制涉及直接的 hPAF1C-SII 相互作用和与 RNA 聚合酶 II 的协同结合。除了具有独特的 PAF1C 功能外，目前的观察结果还为不同转录延伸因子在染色质转录中的协同功能提供了分子机制。
