Garcia-Carranca A, Thierry F, Yaniv M
Genética y Biologia Molecular, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional, D.F. México.
J Virol. 1988 Nov;62(11):4321-30. doi: 10.1128/JVI.62.11.4321-4330.1988.
The long control region of human genital papillomavirus type 18 harbors transcription regulatory elements, such as the E6 promoter and a cell type-specific enhancer independent of the E2 protein. By performing DNase I footprint experiments in vitro with protein extracts from different cell lines and tissues we searched for cellular factors interacting with the totality of the control region. We detected a total of eight different protected sites; most of them were found with all the extracts. Two of these sites, one in the enhancer and the other in the sequences proximal to the E6 cap site, interact with a member of the activator protein 1 family. However, in the absence of fine mutational analysis, we cannot readily discern an exact functional role for the different binding sites. We also characterized two regions, which are protected only in the presence of E2, corresponding to the perfect palindromes ACCGN4CGGT and present either 500 nucleotides or tandemly repeated about 70 nucleotides upstream of the E6 cap site. This last protected area covers a large part of the putative TATA box of the E6 promoter and could explain its repression by bovine papilloma virus type 1 E2, which could interfere with binding of the TFII D ubiquitous transcription factor to the TATA sequence of the promoter.
人乳头瘤病毒18型的长控制区含有转录调控元件，如E6启动子和一个不依赖E2蛋白的细胞类型特异性增强子。通过用来自不同细胞系和组织的蛋白质提取物在体外进行DNA酶I足迹实验，我们寻找与整个控制区相互作用的细胞因子。我们总共检测到八个不同的保护位点；其中大多数在所有提取物中都能找到。其中两个位点，一个在增强子中，另一个在E6帽位点近端的序列中，与激活蛋白1家族的一个成员相互作用。然而，在没有精细突变分析的情况下，我们无法轻易辨别不同结合位点的确切功能作用。我们还鉴定了两个区域，它们仅在存在E2时受到保护，对应于完美回文序列ACCGN4CGGT，位于E6帽位点上游500个核苷酸处或串联重复约70个核苷酸。最后这个受保护区域覆盖了E6启动子假定TATA盒的很大一部分，并且可以解释其被1型牛乳头瘤病毒E2抑制的原因，E2可能会干扰TFII D普遍转录因子与启动子TATA序列的结合。
