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Updated: Aug 5, 2026

A High Resolution Method to Monitor Phosphorylation-dependent Activation of IRF3
Published on: January 24, 2016
Functional characterization of interferon regulatory factor 3a (IRF-3a), an alternative splice isoform of IRF-3
A Y Karpova1, L V Ronco, P M Howley
1Department of Pathology, Harvard Medical School, Boston, Massachusetts 02115, USA.
Abstract:
Virus infection of numerous cell types results in the transcriptional induction of a subset of virus- and interferon (IFN)-stimulated genes. The beta IFN (IFN-beta) gene is one of these rapidly induced genes; it serves as a fundamental component of the cellular defense response in eliciting potent antiviral, immunomodulatory, and antiproliferative effects. One of the transcription factors involved in the stringent regulation of IFN-beta production following virus infection is interferon regulatory factor (IRF) 3 (IRF-3). We have characterized an alternatively spliced isoform of IRF-3 that we have called IRF-3a. IRF-3a can selectively and potently inhibit virus-induced activation of the IFN-beta promoter. IRF-3a lacks half of the DNA binding domain found in IRF-3 and is unable to bind to the classical IRF binding elements, IFN-stimulated response elements. These studies suggest that IRF-3a may act as a modulator of IRF-3.
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