title: Expression of intracellular interferon constitutively activates ISGF3 and confers resistance to EMC viral infection.
abstract: The mechanism(s) by which interferon (IFN)-alpha confers resistance to viruses is currently being characterized. Previous studies have shown that binding of IFN-alpha to its high-affinity receptor activates transcription factor interferon-stimulated gene factor 3 (ISGF3), which positively regulates a number of antiviral genes including 2'-5'-oligoadenylate synthetase (2-5A synthetase). We show that mouse L cells expressing nonsecreted (intracellular) type I human IFN are less susceptible to encephalomyocarditis (EMC) virus infection and have increased levels of 2-5A synthetase. The 2-5A synthetase promoter is constitutively induced, and the antiviral effects are most likely mediated through activation of ISGF3, which occurs constitutively in cell lines expressing intracellular interferon. These data suggest that the internalization of IFN-alpha may play a role in the antiviral properties associated with IFN.
authors.affiliation: Department of Molecular and Medical Genetics, University of Toronto, Ontario, Canada.
authors.forename: M N
authors.initials: MN
authors.lastname: Rutherford
authors.forename: A
authors.initials: A
authors.lastname: Kumar
authors.forename: B
authors.initials: B
authors.lastname: Coulombe
authors.forename: D
authors.initials: D
authors.lastname: Skup
authors.forename: D H
authors.initials: DH
authors.lastname: Carver
authors.forename: B R
authors.initials: BR
authors.lastname: Williams
mesh_terms: D015088:2',5'-Oligoadenylate Synthetase / Q000235:genetics*; D000818:Animals; D000998:Antiviral Agents / Q000378:metabolism*; D018188:Cardiovirus Infections / Q000503:physiopathology*; D004268:DNA-Binding Proteins / Q000378:metabolism*; D004686:Encephalomyocarditis virus / Q000502:physiology*; D006801:Humans; D007113:Immunity, Innate; D050832:Interferon-Stimulated Gene Factor 3; D050834:Interferon-Stimulated Gene Factor 3, gamma Subunit; D016898:Interferon-alpha / Q000096:biosynthesis* / Q000378:metabolism; D007739:L Cells; D051379:Mice; D014157:Transcription Factors / Q000378:metabolism*; D014158:Transcription, Genetic
chemical_list: D000998:Antiviral Agents; D004268:DNA-Binding Proteins; C494227:IRF9 protein, human; D050832:Interferon-Stimulated Gene Factor 3; D050834:Interferon-Stimulated Gene Factor 3, gamma Subunit; D016898:Interferon-alpha; C494228:Isgf3g protein, mouse; D014157:Transcription Factors; D015088:2',5'-Oligoadenylate Synthetase