Promoter DNA sequence guides factors that position the +1 nucleosome and facilitate TBP binding [sequencing]

Here we present evidence that precise positioning of the +1 promoter nucleosome in yeast is critical for efficient TBP binding and pre-initiation complex assembly, and is determined, at least in part, by the action of two key factors, the essential chromatin remodeler RSC and one (or more) of a small set of ubiquitous pioneer transcription factors (PTFs). Despite their widespread co-localization, we show that RSC and PTFs often act independently to generate accessible chromatin. Furthermore, we present evidence that RSC binding, as well as the strength and directionality of its action on nucleosomes, depends upon the arrangement of two specific DNA motifs relative to nearby PTF binding sites. Our results provide insights into how promoter DNA sequence instructs trans-acting factors to precisely control nucleosome architecture and stimulate transcription initiation.本研究提供证据表明，酵母中+1启动子核小体的精确定位对于高效结合TBP（TATA盒结合蛋白，TATA-binding protein）以及预起始复合物组装至关重要，且该定位至少部分由两类关键因子的作用所决定：一类是必需的染色质重塑因子RSC，另一类是一小类遍在先锋转录因子（PTFs）中的一个或多个。尽管RSC与PTFs存在广泛的共定位现象，本研究证实二者通常可独立发挥作用以形成开放染色质。此外，本研究提供证据显示，RSC的结合及其对核小体作用的强度与方向性，取决于两个特定DNA基序相对于邻近PTF结合位点的排布方式。本研究结果为启动子DNA序列如何指导反式作用因子精准调控核小体架构并促进转录起始提供了新的见解。