For in-cell pull-down assays, clarified whole cell lysates (WCL) transfected with plasmid constructs expressing HA- or Flag-tagged protein were preincubated with NeutrAvidin beads for 2 h (Pierce). Biotin-labeled Poly (I:C) was added, and WCL were incubated for an additional 4 h at 4°C. For cell-free pull-down assays, WCL transfected with HA- or Flag-tagged protein were incubated with anti-HA or anti-Flag beads (Sigma), and proteins were eluted from the beads using the corresponding peptide. The purified proteins were then added to the NeutrAvidin beads and coincubated with Poly(I:C) for 4 h. After incubation, protein complexes were washed 5 times, boiled in 4X loading buffer, and subjected to SDS-PAGE.