title: Simian virus 40 large T antigen induces IFN-stimulated genes through ATR kinase.
abstract: Polyomaviruses encode a large T Ag (LT), a multifunctional protein essential for the regulation of both viral and host cell gene expression and productive viral infection. Previously, we have shown that stable expression of LT protein results in upregulation of genes involved in the IFN induction and signaling pathway. In this study, we focus on the cellular signaling mechanism that leads to the induction of IFN responses by LT. Our results show that ectopic expression of SV40 LT results in the induction of IFN-stimulated genes (ISGs) in human fibroblasts and confers an antiviral state. We describe a LT-initiated DNA damage response (DDR) that activates IFN regulatory factor 1, causing IFN-β production and consequent ISG expression in human cells. This IFN-β and ISG induction is dependent on ataxia-telangiectasia mutated and Rad3-related (ATR) kinase, but independent of ATM. ATR kinase inhibition using a selective kinase inhibitor (ETP-46464) caused a decrease in IFN regulatory factor 1 stabilization and ISG expression. Furthermore, expression of a mutant LT that does not induce DDR also does not induce IFN-β and ISGs. These results show that, in the absence of viral infection, LT-initiated activation of ATR-dependent DDR is sufficient for the induction of an IFN-β-mediated innate immune response in human cells. Thus, we have uncovered a novel and critical role for ATR as a mediator of antiviral responses utilizing LT.
authors.affiliation: Cancer Virology Program, University of Pittsburgh Cancer Institute, Pittsburgh, PA 15213; Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, University of Pittsburgh, Pittsburgh, PA 15213;
authors.forename: Adriana
authors.initials: A
authors.lastname: Forero
authors.affiliation: Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA 15213; and.
authors.forename: Nicholas S
authors.initials: NS
authors.lastname: Giacobbi
authors.affiliation: Cancer Virology Program, University of Pittsburgh Cancer Institute, Pittsburgh, PA 15213; Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, University of Pittsburgh, Pittsburgh, PA 15213;
authors.forename: Kevin D
authors.initials: KD
authors.lastname: McCormick
authors.affiliation: Cancer Virology Program, University of Pittsburgh Cancer Institute, Pittsburgh, PA 15213; Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, University of Pittsburgh, Pittsburgh, PA 15213;
authors.forename: Ole V
authors.initials: OV
authors.lastname: Gjoerup
authors.affiliation: Department of Radiation Oncology, University of Pittsburgh School of Medicine, University of Pittsburgh, Pittsburgh, PA 15213.
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Bakkenist
authors.affiliation: Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA 15213; and.
authors.forename: James M
authors.initials: JM
authors.lastname: Pipas
authors.affiliation: Cancer Virology Program, University of Pittsburgh Cancer Institute, Pittsburgh, PA 15213; Department of Microbiology and Molecular Genetics, University of Pittsburgh School of Medicine, University of Pittsburgh, Pittsburgh, PA 15213; saumen@pitt.edu.
authors.forename: Saumendra N
authors.initials: SN
authors.lastname: Sarkar
mesh_terms: D000952:Antigens, Polyomavirus Transforming / Q000235:genetics / Q000276:immunology*; D064007:Ataxia Telangiectasia Mutated Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000276:immunology; D004249:DNA Damage / Q000235:genetics / Q000276:immunology*; D057809:HEK293 Cells; D006801:Humans; D050856:Interferon Regulatory Factor-1 / Q000235:genetics / Q000276:immunology*; D016899:Interferon-beta / Q000235:genetics / Q000276:immunology*; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D055550:Protein Stability / Q000187:drug effects; D013539:Simian virus 40 / Q000235:genetics / Q000276:immunology*
chemical_list: D000952:Antigens, Polyomavirus Transforming; C494257:IRF1 protein, human; D050856:Interferon Regulatory Factor-1; D047428:Protein Kinase Inhibitors; D016899:Interferon-beta; C576597:ATR protein, human; D064007:Ataxia Telangiectasia Mutated Proteins