Huibregtse J M, Good P D, Marczynski G T, Jaehning J A, Engelke D R
Department of Biological Chemistry, University of Michigan, Ann Arbor 48109-0606.
J Biol Chem. 1993 Oct 25;268(30):22219-22.
The Saccharomyces cerevisiae GAL2 gene upstream activator sequence (UAS) region was examined for protein bound in vivo by chromatin footprinting at high resolution. Gal4 transcriptional activator protein binds to the two consensus UAS sites whether GAL2 expression is induced, uninduced, or repressed by growth with different carbon sources. Although wild type strains show loss of the Gal4 protein-specific footprint in repressing media containing glucose, constitutive high level expression of Gal4 protein restores the GAL2 UAS footprints without fully derepressing GAL2 transcription. Thus binding of the Gal4 activator to target sites in the DNA is required but not sufficient for GAL2 derepression and induction. Gal4-independent protein-DNA complexes were also detected in the region, including one over the previously noted centromere-binding protein (CP1) site upstream of the Gal4 complexes.
利用高分辨率染色质足迹法检测了酿酒酵母GAL2基因上游激活序列（UAS）区域在体内结合的蛋白质。无论GAL2表达是通过不同碳源生长诱导、未诱导还是被抑制，Gal4转录激活蛋白都能结合到两个共有UAS位点。尽管野生型菌株在含有葡萄糖的抑制培养基中显示出Gal4蛋白特异性足迹的丧失，但Gal4蛋白的组成型高水平表达可恢复GAL2 UAS足迹，而不会完全解除对GAL2转录的抑制。因此，Gal4激活剂与DNA中靶位点的结合是GAL2去抑制和诱导所必需的，但并不充分。在该区域还检测到了不依赖Gal4的蛋白质-DNA复合物，包括在Gal4复合物上游先前发现的着丝粒结合蛋白（CP1）位点上的一种复合物。
