Extended Data Fig. 1: RIG-I undergoes LLPS in response to infection of RNA virus.

a, Schematics illustrate the RIG-I-MAVS signalling pathway. b, Left: Domain structure and the low-complexity sequence containing region (R) of RIG-I. Right: Bacterially purified GFP-RIG-I-Strep and RIG-I-Strep proteins were analysed by SDS–PAGE and detected by Coomasssie blue staining. c–e, 20 μM GFP-RIG-I were treated with 5% Hex (c), 100 μg/ml Proteinase K for 30 min at 40 °C (d), or treated with heated-inactivated (5 min at 95 °C and immediately put on ice for 5 min) (e), and then subjected to droplet formation assay in vitro (150 mM NaCl, pH 7.5, room temperature); n = 8 for each experiment. f, Related to Fig. 1g, percentage of cells with puncta was shown; n = 3. g, In vivo fusion of Cy3-labelled 5′ triphosphate double-stranded RNA (5′ppp-dsRNA, hereinafter called dsRNA) and GFP-RIG-I condensate. After 6 h of SeV stimulation, Cy3–dsRNA was transfected into HeLa cells for 6 h. h, Immunofluorescence microscopy and DAPI staining of HeLa cells showed puncta of RIG-I after transfection of Cy3-SARS-CoV-2 RNA for 12 h. i, Left: immunofluorescence microscopy and DAPI staining of GFP-RIG-I with Cy3- dsRNA in HeLa and U2OS cells. Middle and Right: quantitative line profile of co-localization along a white arrow of the left image. j, Representative micrographs of mCherry–MAVS recruited to GFP-RIG-I puncta in HeLa cell infected with SeV for 6 h. Quantitative line profile of colocalization along a white arrow of the right image (left). k, Representative micrographs (middle), and quantification (right) of mouse lung tissue showed puncta of endogenous RIG-I after infection with VSV (2 × 10⁹ p.f.u. per mouse, nasal inhalation); n = 3. Data are representative of at least three independent experiments. Scale bar, 20 μm (c–e), 10 µm (g–j), 50 µm (k). Mean ± s.d., statistical analysis was performed using two-tailed Student’s t-test (c–f,k); ****P < 0.0001. Exact P values, source numerical data are provided.

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