Author contributions
Jie Jin designed the study and performed almost all the experiments except those contributed by others listed below. Jie Jin analyzed the data, prepared the figures, and wrote the original draft. Xianbin Meng assisted in the LC-MS/MS analysis. Yi Yuan provided assistance in the daily experiments such as protein purification and molecular cloning. Haiteng Deng and Yi Huo contributed the plasmid encoding ISG15 conjugating system including ISG15, UBE1L, UBCH8, and HERC5. Xuliang Deng and Jia Song contributed the plasmid encoding RIG-I. Xiaoyun Liu supervised the study, obtained the funding, and rewrote the manuscript.