title: Adeno-associated virus major Rep78 protein disrupts binding of TATA-binding protein to the p97 promoter of human papillomavirus type 16.
abstract: Adeno-associated virus type 2 (AAV) is known to inhibit the promoter activities of several oncogenes and viral genes, including the human papillomavirus type 16 (HPV-16) E6 and E7 transforming genes. However, the target elements of AAV on the long control region (LCR) upstream of E6 and E7 oncogenes are elusive. A chloramphenicol acetyltransferase assay was performed to study the effect of AAV on the transcription activity of the HPV-16 LCR in SiHa (HPV-positive) and C-33A (HPV-negative) cells. The results reveal that (i) AAV inhibited HPV-16 LCR activity in a dose-dependent manner, (ii) AAV-mediated inhibition did not require the HPV gene products, and (iii) the AAV replication gene product Rep78 was involved in the inhibition. Deletion mutation analyses of the HPV-16 LCR showed that regulatory elements outside the core promoter region of the LCR may not be direct targets of AAV-mediated inhibition. Further study with the electrophoretic mobility shift assay demonstrated that Rep78 interfered with the binding of TATA-binding protein (TBP) to the TATA box of the p97 core promoter more significantly than it disrupted the preformed TBP-TATA complex. These data thus suggest that Rep78 may inhibit transcription initiation of the HPV-16 LCR by disrupting the interaction between TBP and the TATA box of the p97 core promoter.
authors.affiliation: Division of Cancer Research, Institute of Biomedical Sciences, Academia Sinica, Taiwan, Republic of China.
authors.forename: P F
authors.initials: PF
authors.lastname: Su
authors.forename: S Y
authors.initials: SY
authors.lastname: Chiang
authors.forename: C W
authors.initials: CW
authors.lastname: Wu
authors.forename: F Y
authors.initials: FY
authors.lastname: Wu
mesh_terms: D002460:Cell Line; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000378:metabolism*; D000229:Dependovirus / Q000737:chemistry / Q000378:metabolism*; D006801:Humans; D009154:Mutation; D027383:Papillomaviridae / Q000235:genetics*; D011401:Promoter Regions, Genetic; D035181:TATA-Box Binding Protein; D020079:Terminal Repeat Sequences / Q000235:genetics; D014157:Transcription Factors / Q000378:metabolism*; D014158:Transcription, Genetic; D014764:Viral Proteins / Q000737:chemistry / Q000378:metabolism*
chemical_list: D004268:DNA-Binding Proteins; D035181:TATA-Box Binding Protein; D014157:Transcription Factors; D014764:Viral Proteins; C068734:rep proteins, Adeno-associated virus 2