Ohba R, Tabuchi H, Hirose S
Department of Genetics, Graduate University for Advanced Studies, Mishima, Japan.
Biochem Biophys Res Commun. 1992 Jul 31;186(2):963-9. doi: 10.1016/0006-291x(92)90840-h.
Assembly of nucleosomes on the adenovirus major late promoter blocked initiation of transcription by RNA polymerase II. However, the formation of transcription preinitiation complexes prevented subsequent assembly of promoter sequences into nucleosomes and allowed transcription on the chromatin templates. When the formation of preinitiation complexes was in competition with nucleosome assembly, transcription on linear or relaxed closed circular DNA was inactivated by nucleosome assembly over the promoter region. However, transcription on partially supercoiled DNA (mean superhelical density of -0.036) remained active because the rapid formation of preinitiation complexes prevented subsequent assembly of promoter sequences into nucleosomes.
腺病毒主要晚期启动子上核小体的组装阻碍了RNA聚合酶II介导的转录起始。然而，转录前起始复合物的形成可防止启动子序列随后组装成核小体，并允许在染色质模板上进行转录。当转录前起始复合物的形成与核小体组装相互竞争时，线性或松弛闭环DNA上的转录会因启动子区域的核小体组装而失活。然而，部分超螺旋DNA（平均超螺旋密度为-0.036）上的转录仍保持活性，因为转录前起始复合物的快速形成可防止启动子序列随后组装成核小体。
