Transcriptional activation of the adenoviral genome is mediated by capsid protein VI

PLoS Pathog. 2012 Feb;8(2):e1002549. doi: 10.1371/journal.ppat.1002549. Epub 2012 Feb 23.

Abstract

Gene expression of DNA viruses requires nuclear import of the viral genome. Human Adenoviruses (Ads), like most DNA viruses, encode factors within early transcription units promoting their own gene expression and counteracting cellular antiviral defense mechanisms. The cellular transcriptional repressor Daxx prevents viral gene expression through the assembly of repressive chromatin remodeling complexes targeting incoming viral genomes. However, it has remained unclear how initial transcriptional activation of the adenoviral genome is achieved. Here we show that Daxx mediated repression of the immediate early Ad E1A promoter is efficiently counteracted by the capsid protein VI. This requires a conserved PPxY motif in protein VI. Capsid proteins from other DNA viruses were also shown to activate the Ad E1A promoter independent of Ad gene expression and support virus replication. Our results show how Ad entry is connected to transcriptional activation of their genome in the nucleus. Our data further suggest a common principle for genome activation of DNA viruses by counteracting Daxx related repressive mechanisms through virion proteins.

MeSH terms

  • Adaptor Proteins, Signal Transducing / genetics
  • Adaptor Proteins, Signal Transducing / physiology
  • Adenoviridae / genetics*
  • Amino Acid Motifs / genetics
  • Amino Acid Motifs / physiology
  • Capsid Proteins / chemistry
  • Capsid Proteins / genetics
  • Capsid Proteins / metabolism
  • Capsid Proteins / physiology*
  • Cells, Cultured
  • Co-Repressor Proteins
  • Gene Expression Regulation, Viral
  • Genes, Viral / physiology
  • Genetic Fitness / physiology
  • Genome, Viral* / genetics
  • Humans
  • Molecular Chaperones
  • Mutant Proteins / chemistry
  • Mutant Proteins / genetics
  • Mutant Proteins / metabolism
  • Mutant Proteins / physiology
  • Nuclear Proteins / genetics
  • Nuclear Proteins / physiology
  • Transcription Factors / genetics
  • Transcription Factors / metabolism
  • Transcription Factors / physiology
  • Transcriptional Activation / genetics*
  • Transfection
  • Viral Proteins / chemistry
  • Viral Proteins / metabolism
  • Viral Proteins / physiology
  • Virus Replication / genetics

Substances

  • Adaptor Proteins, Signal Transducing
  • Capsid Proteins
  • Co-Repressor Proteins
  • DAXX protein, human
  • Molecular Chaperones
  • Mutant Proteins
  • Nuclear Proteins
  • Transcription Factors
  • Viral Proteins