Beard P, Bruggmann H
Swiss Institute for Experimental Cancer Research, Lausanne.
J Virol. 1988 Nov;62(11):4296-302. doi: 10.1128/JVI.62.11.4296-4302.1988.
We have characterized a transcription factor, obtained from simian virus 40 (SV40) chromosomes, which activates transcription from the SV40 late promoter in vitro. The late promoter-activating factor was distinct from SV40 T antigen as judged by its behavior on chromatography on hydroxylapatite; it was not recognized by anti-T antibodies, while T antigen itself was recognized. T antigen from SV40 chromosomes, on the other hand, abolished transcription in vitro from the early promoter. In DNase I footprinting experiments, a partially purified late promoter-activating factor preparation protected a region of DNA centered on SV40 nucleotide 270, which is between the repeated 72-base-pair enhancer and the major late RNA start site. Proteins from HeLa cells did not give the same footprint at this position. Gel mobility shift assays showed that proteins from SV40-infected CV-1 cells form a complex with DNA containing this binding site. The complex has a different rate of gel migration and a higher stability than complexes formed with proteins from uninfected cells.
我们已鉴定出一种从猿猴病毒40（SV40）染色体中获得的转录因子，它在体外可激活SV40晚期启动子的转录。通过其在羟基磷灰石层析上的行为判断，晚期启动子激活因子与SV40 T抗原不同；抗T抗体无法识别它，而T抗原本身可被识别。另一方面，SV40染色体中的T抗原在体外可消除早期启动子的转录。在DNA酶I足迹实验中，一种部分纯化的晚期启动子激活因子制剂保护了以SV40核苷酸270为中心的一段DNA区域，该区域位于重复的72碱基对增强子和主要晚期RNA起始位点之间。来自HeLa细胞的蛋白质在该位置没有给出相同的足迹。凝胶迁移率变动分析表明，来自SV40感染的CV-1细胞的蛋白质与含有该结合位点的DNA形成复合物。与未感染细胞的蛋白质形成的复合物相比，该复合物具有不同的凝胶迁移速率和更高的稳定性。
