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Interaction between JCV large T-antigen and beta-catenin

Dai-Di Gan1, Kamel Khalili

  • 1Center for Neurovirology and Cancer Biology, Temple University, 1900 North 12th Street, 015-96, Room 203, Philadelphia, PA 19122, USA.

Oncogene
|January 16, 2004
PubMed

Insights

The John Cunningham virus (JCV) T-antigen interacts with beta-catenin, stabilizing it and promoting its nuclear entry. This interaction activates Wnt signaling, contributing to cerebellar tumor development.

Area of Science:

  • Neuro-oncology
  • Viral oncology
  • Molecular biology

Background:

  • John Cunningham virus (JCV) T-antigen expression causes cerebellar tumors in mice.
  • JCV is associated with human primitive neuroectodermal tumors (PNETs).
  • The Wnt signaling pathway is implicated in cerebellar tumor development.

Purpose of the Study:

  • To investigate the interaction between JCV T-antigen and beta-catenin, a key Wnt pathway protein.
  • To elucidate the mechanism by which T-antigen influences beta-catenin activity.
  • To identify a novel oncogenic pathway for JCV T-antigen.

Main Methods:

  • Investigated physical interaction between T-antigen and beta-catenin using specific protein domains.
  • Assessed beta-catenin levels and cellular localization in the presence of T-antigen.
  • Measured downstream target gene promoter activity (e.g., c-myc) upon T-antigen and beta-catenin coexpression.

Main Results:

  • Demonstrated direct physical interaction between JCV T-antigen (residues 82-628) and beta-catenin (residues 695-781).
  • T-antigen binding increases beta-catenin stability and promotes its nuclear translocation.
  • Coexpression of T-antigen and beta-catenin enhances transcription of Wnt-dependent promoters, including c-myc.

Conclusions:

  • JCV T-antigen physically interacts with beta-catenin, stabilizing it and facilitating its nuclear import.
  • This interaction represents a novel oncogenic pathway for JCV, contributing to tumor formation.
  • JCV T-antigen can deregulate the Wnt pathway by stabilizing beta-catenin, offering a new mechanism for viral oncogenesis.

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