Papillomavirus E7 oncoproteins share functions with polyomavirus small T antigens

Elizabeth A. White, Rebecca E. Kramer, Justin H. Hwang, Arun T. Pores Fernando, Nana Naetar, William C. Hahn, Thomas M. Roberts, Brian S. Schaffhausen, David M. Livingston, Peter M. Howley

Research output: Contribution to journalArticlepeer-review

12 Scopus citations


Many of the small DNA tumor viruses encode transforming proteins that function by targeting critical cellular pathways involved in cell proliferation and survival. In this study, we have examined whether some of the functions of the polyomavirus small T antigens (ST) are shared by the E6 and E7 oncoproteins of two oncogenic papillomaviruses. Using three different assays, we have found that E7 can provide some simian virus 40 (SV40) or murine polyomavirus (PyV) ST functions. Both human papillomavirus 16 (HPV16) and bovine papillomavirus (BPV1) E7 proteins are capable of partially substituting for SV40 ST in a transformation assay that also includes SV40 large T antigen, the catalytic subunit of cellular telomerase, and oncogenic Ras. Like SV40 ST, HPV16 E7 has the ability to override a quiescence block induced by mitogen deprivation. Like PyV ST, it also has the ability to inhibit myoblast differentiation. At least two of these activities are dependent upon the interaction of HPV16 E7 with retinoblastoma protein family members. For small T antigens, interaction with PP2A is needed for each of these functions. Even though there is no strong evidence that E6 or E7 share the ability of small T to interact with PP2A, E7 provides these functions related to cellular transformation.

Original languageEnglish (US)
Pages (from-to)2857-2865
Number of pages9
JournalJournal of virology
Issue number5
StatePublished - 2015
Externally publishedYes

Bibliographical note

Publisher Copyright:
© 2015, American Society for Microbiology.


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