title: Human Papillomavirus 16 E6 Upregulates APOBEC3B via the TEAD Transcription Factor.
abstract: The cytidine deaminase APOBEC3B (A3B) underlies the genetic heterogeneity of several human cancers, including cervical cancer, which is caused by human papillomavirus (HPV) infection. We previously identified a region within the A3B promoter that is activated by the viral protein HPV16 E6 in human keratinocytes. Here, we discovered three sites recognized by the TEAD family of transcription factors within this region of the A3B promoter. Reporter assays in HEK293 cells showed that exogenously expressed TEAD4 induced A3B promoter activation through binding to these sites. Normal immortalized human keratinocytes expressing E6 (NIKS-E6) displayed increased levels of TEAD1/4 protein compared to parental NIKS. A series of E6 mutants revealed that E6-mediated degradation of p53 was important for increasing TEAD4 levels. Knockdown of TEADs in NIKS-E6 significantly reduced A3B mRNA levels, whereas ectopic expression of TEAD4 in NIKS increased A3B mRNA levels. Finally, chromatin immunoprecipitation assays demonstrated increased levels of TEAD4 binding to the A3B promoter in NIKS-E6 compared to NIKS. Collectively, these results indicate that E6 induces upregulation of A3B through increased levels of TEADs, highlighting the importance of the TEAD-A3B axis in carcinogenesis.IMPORTANCEThe expression of APOBEC3B (A3B), a cellular DNA cytidine deaminase, is upregulated in various human cancers and leaves characteristic, signature mutations in cancer genomes, suggesting that it plays a prominent role in carcinogenesis. Viral oncoproteins encoded by human papillomavirus (HPV) and polyomavirus have been reported to induce A3B expression, implying the involvement of A3B upregulation in virus-associated carcinogenesis. However, the molecular mechanisms causing A3B upregulation remain unclear. Here, we demonstrate that exogenous expression of the cellular transcription factor TEAD activates the A3B promoter. Further, the HPV oncoprotein E6 increases the levels of endogenous TEAD1/4 protein, thereby leading to A3B upregulation. Since increased levels of TEAD4 are frequently observed in many cancers, an understanding of the direct link between TEAD and A3B upregulation is of broad oncological interest.
authors.affiliation: Pathogen Genomics Center, National Institute of Infectious Diseases, Tokyo, Japan moris@nih.go.jp.
authors.forename: Seiichiro
authors.initials: S
authors.lastname: Mori
authors.affiliation: Pathogen Genomics Center, National Institute of Infectious Diseases, Tokyo, Japan.
authors.forename: Takamasa
authors.initials: T
authors.lastname: Takeuchi
authors.affiliation: Pathogen Genomics Center, National Institute of Infectious Diseases, Tokyo, Japan.
authors.forename: Yoshiyuki
authors.initials: Y
authors.lastname: Ishii
authors.affiliation: Division of Carcinogenesis and Cancer Prevention, National Cancer Center Research Institute, Tokyo, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Yugawa
authors.affiliation: Division of Carcinogenesis and Cancer Prevention, National Cancer Center Research Institute, Tokyo, Japan.
authors.forename: Tohru
authors.initials: T
authors.lastname: Kiyono
authors.affiliation: Department of Developmental and Regenerative Biology, Medical Research Institute, Tokyo Medical and Dental University, Tokyo, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Nishina
authors.affiliation: Pathogen Genomics Center, National Institute of Infectious Diseases, Tokyo, Japan.
authors.forename: Iwao
authors.initials: I
authors.lastname: Kukimoto
mesh_terms: D002460:Cell Line; D047369:Chromatin Immunoprecipitation; D003564:Cytidine Deaminase / Q000096:biosynthesis*; D004268:DNA-Binding Proteins / Q000378:metabolism*; D004847:Epithelial Cells / Q000821:virology; D015870:Gene Expression; D055785:Gene Knockdown Techniques; D054884:Host-Pathogen Interactions; D052162:Human papillomavirus 16 / Q000502:physiology*; D006801:Humans; D015778:Minor Histocompatibility Antigens / Q000096:biosynthesis*; D009124:Muscle Proteins / Q000378:metabolism*; D009687:Nuclear Proteins / Q000378:metabolism*; D009856:Oncogene Proteins, Viral / Q000378:metabolism*; D059748:Proteolysis; D012097:Repressor Proteins / Q000378:metabolism*; D000091262:TEA Domain Transcription Factors; D014157:Transcription Factors / Q000378:metabolism*; D014158:Transcription, Genetic; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism; D015854:Up-Regulation
chemical_list: D004268:DNA-Binding Proteins; C068651:E6 protein, Human papillomavirus type 16; D015778:Minor Histocompatibility Antigens; D009124:Muscle Proteins; D009687:Nuclear Proteins; D009856:Oncogene Proteins, Viral; D012097:Repressor Proteins; D000091262:TEA Domain Transcription Factors; C057182:TEAD1 protein, human; C486309:TEAD4 protein, human; D014157:Transcription Factors; D016159:Tumor Suppressor Protein p53; C495794:APOBEC3B protein, human; D003564:Cytidine Deaminase
keywords: APOBEC3B; E6; TEAD; papillomavirus