title: Phosphorylation sites of the E2 transcriptional regulatory proteins of bovine papillomavirus type 1.
abstract: The E2 open reading frame of bovine papillomavirus type 1 (BPV-1) encodes three transcriptional regulatory proteins. The full-length open reading frame encodes a protein of 410 amino acids which functions as a transcriptional transactivator. Two transcriptional repressor proteins, E2-TR and E8/E2, contain the C-terminal 249 and 204 amino acids, respectively. We have expressed both the full-length E2 protein and the E2-TR repressor protein in insect cells, by using recombinant baculoviruses, and in mammalian COS-1 cells, by using a chimeric simian virus 40/BPV-1 virus. Analysis of the E2 proteins revealed that both the transactivator and repressor forms are phosphorylated predominately on serine residues at similar sites in both expression systems. By a combination of peptide mapping and site-directed mutagenesis techniques, the serine residues at positions 298 and 301 were determined to be the major phosphorylation sites of the BPV-1 E2 proteins.
authors.affiliation: Laboratory of Tumor Virus Biology, National Cancer Institute, Bethesda, Maryland 20892.
authors.forename: A A
authors.initials: AA
authors.lastname: McBride
authors.forename: J B
authors.initials: JB
authors.lastname: Bolen
authors.forename: P M
authors.initials: PM
authors.lastname: Howley
mesh_terms: D000595:Amino Acid Sequence; D000596:Amino Acids / Q000032:analysis; D000818:Animals; D001483:Base Sequence; D052688:Bovine papillomavirus 1 / Q000235:genetics* / Q000378:metabolism; D002460:Cell Line; D004279:DNA, Viral / Q000235:genetics; D015870:Gene Expression; D005814:Genes, Viral; D005822:Genetic Vectors; D007304:Insect Viruses / Q000235:genetics; D008969:Molecular Sequence Data; D009154:Mutation; D027383:Papillomaviridae / Q000235:genetics*; D010449:Peptide Mapping; D010766:Phosphorylation; D010957:Plasmids; D012097:Repressor Proteins / Q000235:genetics* / Q000378:metabolism; D015534:Trans-Activators / Q000235:genetics* / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism; D015678:Viral Structural Proteins / Q000235:genetics
chemical_list: D000596:Amino Acids; D004279:DNA, Viral; D012097:Repressor Proteins; D015534:Trans-Activators; D014157:Transcription Factors; D015678:Viral Structural Proteins