IFN-regulatory factor 3-dependent gene expression is defective in Tbk1-deficient mouse embryonic fibroblasts
Department of Molecular and Cellular Biology; Department of Medicine, Division of Infectious Diseases and Immunology
Immunology and Infectious Disease | Life Sciences | Medicine and Health Sciences
Virus infection, double-stranded RNA, and lipopolysaccharide each induce the expression of genes encoding IFN-alpha and -beta and chemokines, such as RANTES (regulated on activation, normal T cell expressed and secreted) and IP-10 (IFN-gamma inducible protein 10). This induction requires the coordinate activation of several transcription factors, including IFN-regulatory factor 3 (IRF3). The signaling pathways leading to IRF3 activation are triggered by the binding of pathogen-specific products to Toll-like receptors and culminate in the phosphorylation of specific serine residues in the C terminus of IRF3. Recent studies of human cell lines in culture have implicated two noncanonical IkappaB kinase (IKK)-related kinases, IKK-epsilon and Traf family member-associated NF-kappaB activator (TANK)-binding kinase 1 (TBK1), in the phosphorylation of IRF3. Here, we show that purified recombinant IKK-epsilon and TBK1 directly phosphorylate the critical serine residues in IRF3. We have also examined the expression of IRF3-dependent genes in mouse embryonic fibroblasts (MEFs) derived from Tbk1(-/-) mice, and we show that TBK1 is required for the activation and nuclear translocation of IRF3 in these cells. Moreover, Tbk1(-/-) MEFs show marked defects in IFN-alpha and -beta, IP-10, and RANTES gene expression after infection with either Sendai or Newcastle disease viruses or after engagement of the Toll-like receptors 3 and 4 by double-stranded RNA and lipopolysaccharide, respectively. Finally, TRIF (TIR domain-containing adapter-inducing IFN-beta), fails to activate IRF3-dependent genes in Tbk1(-/-) MEFs. We conclude that TBK1 is essential for IRF3-dependent antiviral gene expression.
DOI of Published Version
Proc Natl Acad Sci U S A. 2004 Jan 6;101(1):233-8. Epub 2003 Dec 16. Link to article on publisher's site
Proceedings of the National Academy of Sciences of the United States of America
McWhirter SM, Fitzgerald KA, Rosains J, Rowe DC, Golenbock DT, Maniatis T. (2003). IFN-regulatory factor 3-dependent gene expression is defective in Tbk1-deficient mouse embryonic fibroblasts. GSBS Student Publications. https://doi.org/10.1073/pnas.2237236100. Retrieved from https://escholarship.umassmed.edu/gsbs_sp/843