Phenotypic analysis of bovine papillomavirus type 1 E2 repressor mutants.
The bovine papillomavirus type 1 (BPV-1) E2 open reading frame encodes three proteins: the E2 transcriptional transactivator, the E2 transcriptional repressor (E2-TR), and the E8/E2 fusion peptide. In this study, we describe the phenotypes of BPV-1 mutants which are disrupted in their capacity to encode either the E2 transcriptional repressor or the E8/E2 fusion peptide. We also describe experiments which demonstrate that the E8/E2 gene product functions similarly to E2-TR. In the context of the entire viral genome, disruption of E8/E2 expression had little effect on viral processes, whereas disruption of E2-TR expression resulted in a complex phenotype marked by a 10- to 20-fold increase in viral DNA plasmid copy number as well as increased transformation potential. A double mutant, defective in the expression of both E8/E2 and E2-TR proteins, had high levels of E2 transactivation activity yet had reduced plasmid replication capacity and a delayed capacity to transform rodent cells.
Lambert
P F
PF
Laboratory of Tumor Virus Biology, National Cancer Institute Bethesda, Maryland 20892.
Monk
B C
BC
Howley
P M
PM
D000818:Animals; D001483:Base Sequence; D052688:Bovine papillomavirus 1 / Q000235:genetics*; D002460:Cell Line; D002471:Cell Transformation, Neoplastic; D004279:DNA, Viral / Q000138:chemical synthesis / Q000235:genetics; D005809:Genes, Regulator; D005814:Genes, Viral; D008969:Molecular Sequence Data; D009154:Mutation; D015345:Oligonucleotide Probes / Q000138:chemical synthesis / Q000235:genetics; D027383:Papillomaviridae / Q000235:genetics*; D010641:Phenotype; D010957:Plasmids; D012097:Repressor Proteins / Q000235:genetics; D015183:Restriction Mapping; D015534:Trans-Activators / Q000235:genetics; D014158:Transcription, Genetic; D015678:Viral Structural Proteins / Q000235:genetics*
D004279:DNA, Viral; D015345:Oligonucleotide Probes; D012097:Repressor Proteins; D015534:Trans-Activators; D015678:Viral Structural Proteins