High and low levels of cottontail rabbit papillomavirus E2 protein generate opposite effects on gene expression

J Biol Chem. 2001 Jan 12;276(2):867-74. doi: 10.1074/jbc.M007120200.

Abstract

The papillomavirus E2 protein plays an important role in viral transcriptional regulation and replication. We chose to study the cottontail rabbit papillomavirus (CRPV) E2 protein as a transcriptional regulator because of the availability of an animal model for papilloma formation, which may be relevant for human papillomavirus (HPV) infection and replication. We studied the effect of expression levels of E2 on the long control region, which contains transcriptional promoter and enhancer elements, and synthetic E2-dependent artificial promoters in which the E2 was the dominant factor in the transcriptional activation. These experiments indicated that high levels of E2 were inhibitory and low levels were stimulatory for transactivation. In addition, we showed that the complex formed between CRPV E2 and the cognate binding site was less stable than the complex formed between HPV E2 and the same cognate binding site. Furthermore, we showed that CRPV E2 binding to its transcriptional regulatory sequence was stabilized by other proteins such as E1, which produced increments in transcriptional activation of E2-dependent genes. The data may be used to define conditions in which the rabbit model can be used for the screening of drugs which are inhibitory to the HPV and CRPV replication and gene expression.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Base Sequence
  • Binding Sites
  • Cell Line
  • Cottontail rabbit papillomavirus / genetics*
  • Cottontail rabbit papillomavirus / physiology
  • Gene Expression Regulation, Viral*
  • Genes, Reporter
  • Molecular Sequence Data
  • Oncogene Proteins / genetics*
  • Oncogene Proteins / metabolism*
  • Polymerase Chain Reaction
  • Promoter Regions, Genetic
  • Rabbits
  • Recombinant Proteins / metabolism
  • Regulatory Sequences, Nucleic Acid
  • Spodoptera
  • Transcription Factors / genetics*
  • Transcription Factors / metabolism*
  • Transcription, Genetic
  • Transcriptional Activation
  • Transfection
  • Viral Proteins / genetics*
  • Viral Proteins / metabolism*

Substances

  • E2 protein, Cottontail rabbit papillomavirus
  • Oncogene Proteins
  • Recombinant Proteins
  • Transcription Factors
  • Viral Proteins