Kubik Slawomir, Bruzzone Maria Jessica, Shore David
Department of Molecular Biology and Institute of Genetics and Genomics in Geneva (iGE3), University of Geneva, Geneva, Switzerland.
Bioessays. 2017 May;39(5). doi: 10.1002/bies.201600237. Epub 2017 Mar 27.
Improvements in deep sequencing, together with methods to rapidly deplete essential transcription factors (TFs) and chromatin remodelers, have recently led to a more detailed picture of promoter nucleosome architecture in yeast and its relationship to transcriptional regulation. These studies revealed that ∼40% of all budding yeast protein-coding genes possess a unique promoter structure, where we propose that an unusually unstable nucleosome forms immediately upstream of the transcription start site (TSS). This "fragile" nucleosome (FN) promoter architecture relies on the combined action of the essential RSC (Remodels Structure of Chromatin) nucleosome remodeler and pioneer transcription factors (PTFs). FNs are associated with genes whose expression is high, coupled to cell growth, and characterized by low cell-to-cell variability (noise), suggesting that they may promote these features. Recent studies in metazoans suggest that the presence of dynamic nucleosomes upstream of the TSS at highly expressed genes may be conserved throughout evolution.
深度测序技术的改进，以及快速耗尽必需转录因子（TFs）和染色质重塑因子的方法，最近使我们对酵母中启动子核小体结构及其与转录调控的关系有了更详细的了解。这些研究表明，所有出芽酵母蛋白质编码基因中约40%具有独特的启动子结构，我们认为在转录起始位点（TSS）上游会形成一个异常不稳定的核小体。这种“脆弱”核小体（FN）启动子结构依赖于必需的RSC（重塑染色质结构）核小体重塑因子和先锋转录因子（PTF）的共同作用。FN与那些表达水平高、与细胞生长相关且细胞间变异性（噪音）低的基因相关，这表明它们可能促进了这些特征。后生动物的最新研究表明，在高表达基因的TSS上游存在动态核小体这一现象可能在整个进化过程中都是保守的。
