An interaction between human papillomavirus 16 E2 and TopBP1 is required for optimum viral DNA replication and episomal genome establishment

Mary M. Donaldson, Lorna J. Mackintosh, Jason M. Bodily, Edward S. Dornan, Laimonis A. Laimins, Iain M. Morgan*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

34 Scopus citations

Abstract

In human papillomavirus DNA replication, the viral protein E2 forms homodimers and binds to 12-bp palindromic DNA sequences surrounding the origin of DNA replication. Via a protein-protein interaction, it then recruits the viral helicase E1 to an A/T-rich origin of replication, whereupon a dihexamer forms, resulting in DNA replication initiation. In order to carry out DNA replication, the viral proteins must interact with host factors that are currently not all known. An attractive cellular candidate for regulating viral replication is TopBP1, a known interactor of the E2 protein. In mammalian DNA replication, TopBP1 loads DNA polymerases onto the replicative helicase after the G1-to-S transition, and this process is tightly cell cycle controlled. The direct interaction between E2 and TopBP1 would allow E2 to bypass this cell cycle control, resulting in DNA replication more than once per cell cycle, which is a requirement for the viral life cycle. We report here the generation of an HPV16 E2 mutant compromised in TopBP1 interaction in vivo and demonstrate that this mutant retains transcriptional activation and repression functions but has suboptimal DNA replication potential. Introduction of this mutant into a viral life cycle model results in the failure to establish viral episomes. The results present a potential new antiviral target, the E2-TopBP1 interaction, and increase our understanding of the viral life cycle, suggesting that the E2-TopBP1 interaction is essential.

Original languageEnglish (US)
Pages (from-to)12806-12815
Number of pages10
JournalJournal of virology
Volume86
Issue number23
DOIs
StatePublished - Dec 2012

ASJC Scopus subject areas

  • Microbiology
  • Immunology
  • Insect Science
  • Virology

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