Stetter G, Montenarh M
Department of Biochemistry, University of Ulm, Federal Republic of Germany.
Oncogene. 1989 Nov;4(11):1353-7.
SV40 large T antigen interacts specifically with three different DNA sequences within the SV40 control region namely site I, II and III, in order to regulate the viral DNA replication and the stimulation of late, or repression of early viral transcription. We define three different plasmids, containing either site I alone, site II with SV40 specific flanking sequences or both sites I and II with additional neighbouring sequences which were used to study the interaction of T antigen with each of its binding sites. We found that binding of T antigen to site II reduced binding of T antigen to site I as opposed to the interaction of T antigen with site I alone. These results were supported by our findings that T antigen from an SV40 temperature-sensitive mutant, tsA58, which is heat-sensitive for binding to site II, exhibited the same binding affinity for site I as for the DNA fragment containing both binding sites. Thus, binding of T antigen to binding site II seems to interfere with binding to site I, thereby influencing the regulatory functions of T antigen in the repression of early viral gene transcription.
SV40大T抗原与SV40控制区域内的三个不同DNA序列特异性相互作用，即位点I、II和III，以调节病毒DNA复制以及晚期病毒转录的刺激或早期病毒转录的抑制。我们定义了三种不同的质粒，分别单独包含位点I、包含SV40特异性侧翼序列的位点II或同时包含位点I和II以及额外相邻序列，用于研究T抗原与其每个结合位点的相互作用。我们发现，与T抗原单独与位点I相互作用相反，T抗原与位点II的结合降低了T抗原与位点I的结合。我们的研究结果支持了这些结果，即来自SV40温度敏感突变体tsA58的T抗原，其对位点II的结合对热敏感，对位点I的结合亲和力与对包含两个结合位点的DNA片段的结合亲和力相同。因此，T抗原与结合位点II的结合似乎会干扰与位点I的结合，从而影响T抗原在抑制早期病毒基因转录中的调节功能。
