■大量工作在结构上详细揭示了负责mRNA基因转录起始的机制的组成部分。这些包括一般转录因子(GTF),在辅因子和位点特异性转录因子(TF)的活性的帮助下,它们与RNA聚合酶II(PolII)一起在启动子处组装以形成预起始复合物(PIC)。然而,人们对体内PIC组装途径及其动力学了解较少,了解这一点对于在机理水平上确定体内RNA合成的速率如何建立以及辅因子和TFs如何影响它们至关重要。
■我们使用竞争ChIP来获得五个GTF的停留时间的基因组规模估计:TBP,TFIIA,TFIIB,出芽酵母中的TFIIE和TFIIF。虽然许多GTF-染色质相互作用是短暂的(<1分钟),有许多相互作用与停留时间在几分钟的范围内。具有共享功能的基因组也共享GTF动力学行为的相似模式。TFIIE,在组装过程后期进入PIC的GTF,停留时间与RNA合成速率相关。
■此处报告的数据集和结果提供了该生物体中大多数PolII驱动基因的动力学信息,因此为探索PIC组装之间的机制关系提供了丰富的资源,基因调控,和转录。基因功能和GTF动力学之间的关系表明,共享的TF集可调节PIC组装动力学以确保适当的表达水平。
UNASSIGNED: A great deal of work has revealed in structural detail the components of the machinery responsible for mRNA gene transcription initiation. These include the general transcription factors (GTFs), which assemble at promoters along with RNA Polymerase II (Pol II) to form a preinitiation complex (PIC) aided by the activities of cofactors and site-specific transcription factors (TFs). However, less well understood are the in vivo PIC assembly pathways and their kinetics, an understanding of which is vital for determining on a mechanistic level how rates of in vivo RNA synthesis are established and how cofactors and TFs impact them.
UNASSIGNED: We used competition ChIP to obtain genome-scale estimates of the residence times for five GTFs: TBP, TFIIA, TFIIB, TFIIE and
TFIIF in budding yeast. While many GTF-chromatin interactions were short-lived (< 1 min), there were numerous interactions with residence times in the several minutes range. Sets of genes with a shared function also shared similar patterns of GTF kinetic behavior. TFIIE, a GTF that enters the PIC late in the assembly process, had residence times correlated with RNA synthesis rates.
UNASSIGNED: The datasets and results reported here provide kinetic information for most of the Pol II-driven genes in this organism and therefore offer a rich resource for exploring the mechanistic relationships between PIC assembly, gene regulation, and transcription. The relationships between gene function and GTF dynamics suggest that shared sets of TFs tune PIC assembly kinetics to ensure appropriate levels of expression.