Fig. 5.

RIG-I splice variant inhibits virus-induced RIG-I multimerization and RIG-I-MAVS complex formation. (A) The important role of the C-terminal RD of RIG-I splice variant for its inhibitory activity. After transfection with vector, RIG-I SV, or its mutants (K₂₇₀A or C₈₁₀,₈₁₃A) together with IFN-β luciferase and pGK-β-gal, HEK293T cells were mock-infected or infected with SeV (50 HA units/ml) for 15 h. Data represent the mean ± SD (n = 3). (B) RIG-I splice variant interacts with RIG-I WT. After transfection with Flag-RIG-I WT, Flag-RIG-I SV, or Flag-RIG-I T₅₅I together with Myc-RIG-I WT, HEK293T were mock-infected or infected with SeV (50 HA units per ml) for 15 h and WCLs were used for IP with α-Myc, followed by IB with α-Flag. (C) RIG-I splice variant interferes with virus-induced RIG-I multimerization. Upon expression of Flag-RIG-I SV or RIG-I T₅₅I, Myc-RIG-I WT multimerization was determined by IB with α-Myc in native PAGE. To detect RIG-I monomer, the lower part of the membrane was exposed for a longer period of time (second from top). (D) RIG-I splice variant inhibits RIG-I-MAVS-interaction. HEK293T were cotransfected with MAVS-CARD-PRD-Flag and Myc-RIG-I WT together with vector, V5-RIG-I SV, or V5-RIG-I T₅₅I and subsequently either mock-treated or infected with SeV (50 HA units per ml) for 15 h. WCLs were subjected to IP with α-Myc, followed by IB with α-Flag.