Duck RIG-I CARD Domain Induces the Chicken IFN-β by Activating NF-κB

Biomed Res Int. 2015:2015:348792. doi: 10.1155/2015/348792. Epub 2015 Mar 30.

Abstract

Retinoic acid-inducible gene I- (RIG-I-) like receptors (RLRs) have recently been identified as cytoplasmic sensors for viral RNA. RIG-I, a member of RLRs family, plays an important role in innate immunity. Although previous investigations have proved that RIG-I is absent in chickens, it remains largely unknown whether the chicken can respond to RIG-I ligand. In this study, the eukaryotic expression vectors encoding duRIG-I full length (duck RIG-I, containing all domains), duRIG-I N-terminal (containing the two caspase activation and recruitment domain, CARDs), and duRIG-I C-terminal (containing helicase and regulatory domains) labeled with 6∗His tags were constructed successfully and detected by western blotting. Luciferase reporter assay and enzyme-linked immunosorbent assay (ELISA) detected the duRIG-I significantly activated NF-κB and induced the expression of IFN-β when polyinosinic-polycytidylic acid (poly[I:C], synthetic double-stranded RNA) challenges chicken embryonic fibroblasts cells (DF1 cells), while the duRIG-I was inactive in the absence of poly[I:C]. Further analysis revealed that the CARDs (duRIG-I-N) induced IFN-β production regardless of the presence of poly[I:C], while the CARD-lacking duRIG-I (duRIG-I-C) was not capable of activating downstream signals. These results indicate that duRIG-I CARD domain plays an important role in the induction of IFN-β and provide a basis for further studying the function of RIG-I in avian innate immunity.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Animals
  • CARD Signaling Adaptor Proteins / genetics*
  • CARD Signaling Adaptor Proteins / metabolism
  • Chickens
  • Ducks
  • Gene Expression Regulation / genetics
  • Immunity, Innate / genetics*
  • Interferon-beta / biosynthesis*
  • Interferon-beta / genetics
  • NF-kappa B / biosynthesis*
  • NF-kappa B / genetics
  • RNA Helicases / genetics*
  • RNA Helicases / metabolism
  • RNA, Viral / genetics

Substances

  • CARD Signaling Adaptor Proteins
  • NF-kappa B
  • RNA, Viral
  • Interferon-beta
  • RNA Helicases