Albrecht G, Devaux B, Kedinger C
Laboratoire de Génétique Moléculaire des Eucaryotes du CNRS, Faculté de Médecine, Strasbourg, France.
Mol Cell Biol. 1988 Apr;8(4):1534-9. doi: 10.1128/mcb.8.4.1534-1539.1988.
We used DNase I footprinting assays on nuclei isolated from adenovirus-infected cells to examine the nucleoprotein configuration of a 250-base-pair segment which encompasses the adenovirus type 5 major late (ML) and IVa2 promoters. At 12 and 20 h postinfection (p.i.), fine DNase I digestion mapping of wild-type adenovirus-infected cells revealed specific sequences protected from digestion which corresponded to promoter elements required for expression of the ML gene in vivo. At 12 h p.i., a G+C-rich region which lies upstream of the IVa2 cap site and is important for maximal IVa2 activity was also found masked to nuclease activity. At 20 h p.i., however, this element became more sensitive to nuclease attack, while the ML promoter elements stayed protected. No major changes in DNA-protein interactions were detected in the region spanning the ML and IVa2 cap sites upon promoter activation, suggesting that the binding properties of the cognate factors for this region are not modified during the process.
我们对从腺病毒感染细胞中分离出的细胞核进行了DNA酶I足迹分析，以检查一个250碱基对片段的核蛋白结构，该片段包含腺病毒5型主要晚期（ML）和IVa2启动子。在感染后12小时和20小时，对野生型腺病毒感染细胞进行精细的DNA酶I消化图谱分析，发现有特定序列受到保护不被消化，这些序列对应于体内ML基因表达所需的启动子元件。在感染后12小时，还发现位于IVa2帽位点上游的一个富含G+C的区域对核酸酶活性有屏蔽作用，该区域对最大程度的IVa2活性很重要。然而，在感染后20小时，这个元件对核酸酶攻击变得更敏感，而ML启动子元件仍受到保护。在启动子激活后，跨越ML和IVa2帽位点的区域未检测到DNA-蛋白质相互作用的重大变化，这表明该区域同源因子的结合特性在这个过程中没有改变。
