Tinker-Kulberg R L, Fu T J, Geiduschek E P, Kassavetis G A
Department of Biology and Center for Molecular Genetics, University of California, San Diego, La Jolla 92093-0634, USA.
EMBO J. 1996 Sep 16;15(18):5032-9.
Bacteriophage T4 gene 45 protein, gp45, serves as the sliding clamp of viral DNA replication and as the activator of T4 late gene transcription. In the latter context, DNA tracking is an essential feature of the unique mechanism of action. T4 late promoters, which consist of a simple TATA box, TATAAATA, are recognized by the small sigma-family gene 55 protein, gp55, which binds to Escherichia coli RNA polymerase core. A direct and RNA polymerase-independent interaction of gp45 with gp55 has been demonstrated in two ways. (i) gp45 tracks along DNA; co-tracking of gp55 requires the previously documented DNA-loading process of gp45, and can be detected by photochemical crosslinking. (ii) The dynamics of DNA tracking by gp45 can be followed by footprinting; the catenated DNA-tracking state of gp45 is short-lived, but is stabilized by gp55. The ability of this topologically linked DNA-tracking transcriptional activator to interact directly with a promoter recognition protein suggests the existence of multiple pathways of promoter location, which are discussed.
噬菌体T4基因45蛋白（gp45）作为病毒DNA复制的滑动夹以及T4晚期基因转录的激活因子。在后一种情况下，DNA追踪是其独特作用机制的一个基本特征。由简单的TATA框（TATAAATA）组成的T4晚期启动子由小的sigma家族基因55蛋白（gp55）识别，gp55与大肠杆菌RNA聚合酶核心结合。已通过两种方式证明了gp45与gp55之间存在直接且不依赖RNA聚合酶的相互作用。（i）gp45沿着DNA追踪；gp55的共同追踪需要先前记录的gp45的DNA加载过程，并且可以通过光化学交联检测到。（ii）可以通过足迹法追踪gp45对DNA的追踪动态；gp45的连环DNA追踪状态是短暂的，但会被gp55稳定。这种拓扑连接的DNA追踪转录激活因子直接与启动子识别蛋白相互作用的能力表明存在多种启动子定位途径，对此进行了讨论。
Zotero 插件
