Fedor M J, Lue N F, Kornberg R D
Department of Cell Biology, Stanford University School of Medicine, CA 94305.
J Mol Biol. 1988 Nov 5;204(1):109-27. doi: 10.1016/0022-2836(88)90603-1.
Arrays of nucleosomes were positioned with respect to the GAL1-GAL10 intergenic region inserted into Saccharomyces cerevisiae minichromosomes. Deletions of DNA flanking the upstream activation sequence left the array unaltered, showing that nucleosome positioning was not a consequence of sequence-specific histone-DNA interactions but depended on proximity to the galactose-responsive upstream activation sequence (UASG). Replacement of the upstream activation sequence by synthetic oligonucleotides with different protein-binding properties identified a short sequence within this region that is responsible for the ordered array. This sequence overlaps a binding site for GAL4 protein, a positive regulator of transcription, but exerts its effect on chromatin structure independently of GAL4, probably through binding a novel factor that is not GAL-specific.
核小体阵列相对于插入酿酒酵母微型染色体中的GAL1 - GAL10基因间区域进行定位。上游激活序列侧翼的DNA缺失并未改变阵列，这表明核小体定位不是序列特异性组蛋白 - DNA相互作用的结果，而是取决于与半乳糖响应性上游激活序列（UASG）的接近程度。用具有不同蛋白质结合特性的合成寡核苷酸替换上游激活序列，确定了该区域内负责有序阵列的短序列。该序列与转录正调控因子GAL4蛋白的结合位点重叠，但独立于GAL4对染色质结构发挥作用，可能是通过结合一种非GAL特异性的新因子来实现的。
