Chemical synthesis of human papillomavirus type 16 E7 oncoprotein: autonomous protein domains for induction of cellular DNA synthesis and for trans activation.
The human papillomavirus type 16 E7 protein belongs to a family of nuclear oncoproteins that share amino acid sequences and functional homology. To localize biochemical activities associated with E7, we chemically synthesized the full-length 98-amino-acid polypeptide and several deletion mutant peptides. We show that the E7 polypeptide is biologically active and possesses at least two functional domains; the first induces cellular DNA synthesis in quiescent rodent cells, and the second trans activates the adenovirus E1A-inducible early E2 promoter and binds zinc. Further, each domain is autonomous and can function on separate peptides. DNA synthesis induction activity maps within the N-terminal portion of the molecule, which contains sequences related to adenovirus E1A conserved domains 1 and 2 required for cell transformation and binding of the retinoblastoma gene product. trans-Activation and Zn-binding activities map within the C-terminal portion of the molecule, a region which contains Cys-X-X-Cys motifs. trans Activation does not require protein synthesis, implying a mechanism that involves interaction with a preexisting cellular factor(s). E7 trans activates the adenovirus E2 promoter but not other E1A-inducible viral promoters, suggesting the possibility that E7 trans activation involves interaction, directly or indirectly, with cellular transcription factor E2F.
Rawls
J A
JA
Institute for Molecular Virology, St. Louis University Medical Center, Missouri 63110.
Pusztai
R
R
Green
M
M
D000260:Adenoviruses, Human / Q000235:genetics*; D000595:Amino Acid Sequence; D002472:Cell Transformation, Viral; D005814:Genes, Viral; D006367:HeLa Cells / Q000378:metabolism; D006801:Humans; D007700:Kinetics; D008969:Molecular Sequence Data; D008970:Molecular Weight; D009856:Oncogene Proteins, Viral / Q000138:chemical synthesis* / Q000378:metabolism; D027383:Papillomaviridae / Q000235:genetics* / Q000378:metabolism; D050725:Papillomavirus E7 Proteins; D010455:Peptides / Q000138:chemical synthesis; D011401:Promoter Regions, Genetic; D011485:Protein Binding; D011505:Protein-Tyrosine Kinases / Q000138:chemical synthesis; D015533:Transcriptional Activation; D015032:Zinc / Q000378:metabolism
D009856:Oncogene Proteins, Viral; D050725:Papillomavirus E7 Proteins; D010455:Peptides; C059731:oncogene protein E7, Human papillomavirus type 16; D011505:Protein-Tyrosine Kinases; D015032:Zinc