The human stimulator of
interferon gene (
STING) is an important molecule in innate immunity that stimulates
type I interferon (IFN) production. However, the role of duck
STING (duSTING) in innate immunity has yet to be explained. In this study, the full length of the duSTING
cDNA sequence (1149bp), which encodes 382
amino acid (aa) residues, was reported and showed the highest sequence similarity with chicken
STINGs. The phylogenetic analysis based on
STING aa showed that duSTING was grouped onto the birds clade. According to the tissue distribution spectrum analysis, duSTING was highly present in the bursa of Fabricius, glandular stomach, liver, pancreas, and small intestine of ducklings, as well as in the blood and pancreas of the adult duck. DuSTING mainly colocalized with the endoplasmic reticulum (ER) and mitochondria in transfected Baby Hamster Syrian Kidney (BHK21) and duck embryo fibroblasts (
DEF) cells by an indirect immunofluorescence assay. The transfection of the DEFs with duSTING activated NF-κB, which induced the transcription of IFN-β, and the activated IFN induced the
interferon-stimulated response element (ISRE). Furthermore, the overexpression of duSTING significantly upregulated the
mRNA level of duck IFN-β and IFN-stimulated genes (ISGs), such as duMx and duOASL and inhibited the replication of the
double-stranded DNA duck
plague virus (DPV) in vitro. In addition, the knockdown of endogenous duSTING by
shRNA significantly reduced the
poly (I:C) (pIC),
poly (dA:dT), and Tembusu virus (TMUV), induced IFN-β production and significantly promoted DPV replication in vitro. In general, these data demonstrate that duSTING is vital for duck
type I interferon induction and plays an important role in the host defence of DPV
infection.