PDF(Pubmed)
Abstract：
RNA polymerase I (Pol I) is the most specialized eukaryotic Pol. It is only responsible for the synthesis of pre-ribosomal RNA (rRNA), the precursor of 18S, 5.8S and 28S rRNA, the most abundant cellular RNA types. Aberrant Pol I transcription is observed in a wide variety of cancers and its down-regulation is associated with several genetic disorders. The regulation and mechanism of Pol I transcription is increasing in clarity given the numerous high-resolution Pol I structures that have helped bridge seminal genetic and biochemical findings in the field. Here, we review the multifunctional roles of an important TFIIF- and TFIIE-like subcomplex composed of the Pol I subunits A34.5 and A49 in yeast, and PAF49 and PAF53 in mammals. Recent analyses have revealed a dynamic interplay between this subcomplex at nearly every step of the Pol I transcription cycle in addition to new roles in chromatin traversal and the existence of a new helix-turn-helix (HTH) within the A49/PAF53 linker domain that expands its dynamic functions during the Pol I transcription process.
摘要：
RNA聚合酶I(PolI)是最特化的真核Pol。它只负责前核糖体RNA（rRNA）的合成，18S的前身，5.8S和28SrRNA，最丰富的细胞RNA类型。在多种癌症中观察到异常的PolI转录，其下调与几种遗传性疾病有关。鉴于许多高分辨率的PolI结构有助于弥合该领域的开创性遗传和生化发现，PolI转录的调节和机制越来越清晰。这里,我们回顾了酵母中由PolI亚基A34.5和A49组成的重要TFIIF和TFIIE样亚复合物的多功能作用，以及哺乳动物的PAF49和PAF53。最近的分析显示，在PolI转录周期的几乎每个步骤中，该亚复合物之间都存在动态的相互作用，除了在染色质遍历中的新作用以及A49/PAF53接头域中存在新的螺旋-转角-螺旋（HTH）外，在PolI转录过程中扩展了其动态功能。
