Carrillo Elba, Garrido Efrain, Gariglio Patricio
Departamento de Genética y Biología Molecular, CINVESTAV-IPN, DF, México.
Intervirology. 2004;47(6):342-9. doi: 10.1159/000080878.
The bovine and human papillomavirus (BPV/HPV) E2 proteins bind specifically to palindromic sequences ACCGN4CGGT that are concentrated within the viral long control region, where they regulate viral oncogene transcription. E2 can activate viral promoters over relatively large distances within the viral genome and was shown to cooperate with a number of cellular transcription factors. Transcriptional activator proteins, such as E2, are thought to act, at least in part, by influencing the assembly and/or stability of preinitiation complexes and it has been suggested that the transcription factor IID, composed by the TATA-binding protein (TBP) and numerous TBP-associated factors (TAFs), is a possible target of this important viral protein. In this paper, we demonstrate that E2 proteins associate in vitro with several TAFs, in particular with TAFII250 and TAFII80. In addition, we observed that the association of TAFII250 with BPV1 E2 is stronger than with HPV18 E2 and that the carboxy terminal domain of both viral proteins is involved in this interaction. On the other hand, TAFII80 binds with similar strength to both E2 proteins through their amino terminal region. These observations may help to explain the different behavior of bovine and human E2 proteins, since BPV E2 is a stronger transcriptional activator than HPV18 E2.
牛乳头瘤病毒和人乳头瘤病毒（BPV/HPV）的E2蛋白特异性结合回文序列ACCGN4CGGT，这些序列集中在病毒的长控制区域内，在那里它们调节病毒癌基因的转录。E2可以在病毒基因组内相对较长的距离上激活病毒启动子，并已证明它能与多种细胞转录因子协同作用。转录激活蛋白，如E2，被认为至少部分地通过影响起始前复合物的组装和/或稳定性来发挥作用，并且有人提出，由TATA结合蛋白（TBP）和众多TBP相关因子（TAFs）组成的转录因子IID是这种重要病毒蛋白的一个可能靶点。在本文中，我们证明E2蛋白在体外与几种TAFs结合，特别是与TAFII250和TAFII80结合。此外，我们观察到TAFII250与BPV1 E2的结合比与HPV18 E2的结合更强，并且两种病毒蛋白的羧基末端结构域都参与了这种相互作用。另一方面，TAFII80通过其氨基末端区域以相似的强度与两种E2蛋白结合。这些观察结果可能有助于解释牛和人E2蛋白的不同行为，因为BPV E2是比HPV18 E2更强的转录激活剂。
