Szent-Györgyi C, Finkelstein D B, Garrard W T
J Mol Biol. 1987 Jan 5;193(1):71-80. doi: 10.1016/0022-2836(87)90628-0.
In both induced and basally transcribed states, the chromatin structure of the yeast HSP82 heat-shock locus exhibits a remarkable degree of organization with respect to DNA sequence. The promoter region contains a constitutive DNase I hypersensitive site. The transcription unit is markedly sensitive to DNase I, and exhibits a sharp transition from a phased half- to a whole nucleosomal cleavage periodicity at the 3' end. Distant upstream and downstream regions are also organized into distinct arrays of phased nucleosomes. Each array is demarcated by DNase I hypersensitive sites that display internal protected regions, suggesting the presence of DNA binding proteins. In addition, since these sites are of mononucleosomal DNA length, they may acquire a nucleosomal structure under certain environmental conditions without disrupting flanking nucleosomal phasing frames. Thus, the HSP82 locus is organized into specific, phased, chromatin structures that appear to function in transcriptional initiation, RNA polymerase passage, transcriptional termination, and the establishment of chromatin-domain microenvironments.
在诱导状态和基础转录状态下，酵母HSP82热休克基因座的染色质结构在DNA序列方面都表现出显著的组织程度。启动子区域包含一个组成型DNase I超敏位点。转录单元对DNase I明显敏感，并在3'端呈现从阶段性半核小体切割周期到完整核小体切割周期的急剧转变。遥远的上游和下游区域也被组织成不同的阶段性核小体阵列。每个阵列由显示内部保护区域的DNase I超敏位点划定界限，这表明存在DNA结合蛋白。此外，由于这些位点是单核小体DNA长度，它们可能在某些环境条件下获得核小体结构而不破坏侧翼核小体的相位框架。因此，HSP82基因座被组织成特定的、阶段性的染色质结构，这些结构似乎在转录起始、RNA聚合酶通过、转录终止以及染色质域微环境的建立中发挥作用。
