FIG 3.

HTLV-1 Tax interacts with RIP1. (A) S. cerevisiae strain AH109 was cotransformed with Tax, together with the indicated prey plasmids. Only cells coexpressing Tax and RIP1 grew under high-stringency selection conditions, indicating interaction. (B) Schematic diagram of RIP1 and RIP1 deletion mutants. (C) Coimmunoprecipitation (Co-IP) analyses were performed in 293T cells after cotransfecting Tax and FLAG-tagged RIP1 mutants using anti-FLAG antibody. IB analysis detected the indicated proteins. (D) IF assays detected expression of Tax (red) and RIP1(green) in Tax-inducible Jurkat T cells or primary ATL cells after treating with doxycycline (1 μg/ml) for 24 h. (E) Luciferase reporter assays were performed in 293T cells after transfecting IFN-β-luc, PRD-III luciferase, or PRD-II luciferase reporter plasmids, expression vectors encoding FLAG-TRIF, and increasing amounts of Tax. (F) Co-IP analyses were performed in 293T cells after cotransfecting expression plasmids encoding Tax and the FLAG-TRIF or FLAG-RIP1 variant (aa 301 to 588). After 36 h, the cell lysates were pulled down using anti-FLAG antibody and IB analysis was performed using anti-Tax antibody. Error bars, ±SD.