title: Targeted degradation of the retinoblastoma protein by human papillomavirus E7-E6 fusion proteins.
abstract: The E6 and the E7 proteins of the oncogenic human papillomavirus types 16 and 18 can stably associate with p53 and the retinoblastoma protein, respectively. The E6-p53 interaction results in the accelerated degradation of p53 in vitro via the ubiquitin-dependent proteolysis system. In this study we demonstrate that a fusion protein consisting of the N-terminal half of the HPV-16 E7 protein and the full length HPV-16 E6 protein promotes the in vitro degradation of the retinoblastoma protein. This indicates that the property of the HPV-16 E6 protein to stimulate the degradation of p53 can be targeted to other proteins. Unlike the HPV-16 or HPV-18 E6 protein, the E6 proteins of HPV-6 and 11 do not bind to p53 and consequently do not target p53 for degradation. Analogous E7-E6 fusion proteins using the E6 proteins of HPV-6 and HPV-11, however, also have the ability to promote the degradation of the retinoblastoma protein, indicating that the property to target associated proteins for degradation is shared by the anogenital specific HPV E6 proteins.
authors.affiliation: Laboratory of Tumor Virus Biology, National Cancer Institute, Bethesda, MD 20892.
authors.forename: M
authors.initials: M
authors.lastname: Scheffner
authors.forename: K
authors.initials: K
authors.lastname: Münger
authors.forename: J M
authors.initials: JM
authors.lastname: Huibregtse
authors.forename: P M
authors.initials: PM
authors.lastname: Howley
mesh_terms: D001483:Base Sequence; D004247:DNA; D004268:DNA-Binding Proteins; D004591:Electrophoresis, Polyacrylamide Gel; D006801:Humans; D006868:Hydrolysis; D008969:Molecular Sequence Data; D009856:Oncogene Proteins, Viral / Q000378:metabolism*; D027383:Papillomaviridae / Q000378:metabolism*; D050725:Papillomavirus E7 Proteins; D010957:Plasmids; D011233:Precipitin Tests; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D012097:Repressor Proteins; D016160:Retinoblastoma Protein / Q000378:metabolism*; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism
chemical_list: D004268:DNA-Binding Proteins; C068651:E6 protein, Human papillomavirus type 16; C052633:E7 protein, Human papillomavirus type 18; D009856:Oncogene Proteins, Viral; D050725:Papillomavirus E7 Proteins; D011993:Recombinant Fusion Proteins; D012097:Repressor Proteins; D016160:Retinoblastoma Protein; D016159:Tumor Suppressor Protein p53; C059731:oncogene protein E7, Human papillomavirus type 16; D004247:DNA