Identification of unusual E6 and E7 proteins within avian papillomaviruses: Cellular localization, biophysical characterization, and phylogenetic analysis

Koenraad Van Doorslaer, Abdellahi Ould M.hamed Ould Sidi, Katia Zanier, Vladimir Rybin, François Deryckère, Annabel Rector, Robert D. Burk, E. Kurt Lienau, Marc Van Ranst, Gilles Travé

Research output: Contribution to journalArticle

23 Scopus citations

Abstract

Papillomaviruses (PVs) are a large family of small DNA viruses infecting mammals, reptiles, and birds. PV infection induces cell proliferation that may lead to the formation of orogenital or skin tumors. PV-induced cell proliferation has been related mainly to the expression of two small oncoproteins, E6 and E7. In mammalian PVs, E6 contains two 70-residue zinc-binding repeats, whereas E7 consists of a natively unfolded N-terminal region followed by a zinc-binding domain which folds as an obligate homodimer. Here, we show that both the novel francolin bird PV Francolinus leucoscepus PV type 1 (FlPV-1) and the chaffinch bird PV Fringilla coelebs PV contain unusual E6 and E7 proteins. The avian E7 proteins contain an extended unfolded N terminus and a zinc-binding domain of reduced size, whereas the avian E6 proteins consist of a single zinc-binding domain. A comparable single-domain E6 protein may have existed in a common ancestor of mammalian and avian PVs. Mammalian E6 C-terminal domains are phylogenetically related to those of single-domain avian E6, whereas mammalian E6 N-terminal domains seem to have emerged by duplication and subsequently diverged from the original ancestral domain. In avian and mammalian cells, both FlPV-1 E6 and FlPV-1 E7 were evenly expressed in the cytoplasm and the nucleus. Finally, samples of full-length FlPV-1 E6 and the FlPV-1 E7 C-terminal zinc-binding domain were prepared for biophysical analysis. Both constructs were highly soluble and well folded, according to nuclear magnetic resonance spectroscopy measurements.

Original languageEnglish (US)
Pages (from-to)8759-8770
Number of pages12
JournalJournal of virology
Volume83
Issue number17
DOIs
StatePublished - Sep 22 2009

ASJC Scopus subject areas

  • Microbiology
  • Immunology
  • Insect Science
  • Virology

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    Van Doorslaer, K., Sidi, A. O. M. H. O., Zanier, K., Rybin, V., Deryckère, F., Rector, A., Burk, R. D., Lienau, E. K., Van Ranst, M., & Travé, G. (2009). Identification of unusual E6 and E7 proteins within avian papillomaviruses: Cellular localization, biophysical characterization, and phylogenetic analysis. Journal of virology, 83(17), 8759-8770. https://doi.org/10.1128/JVI.01777-08