BCLX_L is a critical survival factor against flavivirus infection.

(A) Expression of BCLXL, MCL1, BAK, and BAX in parental, BCLXKO and MCL1KO Huh7 cells was determined by immunoblotting. (B) Parental, BCLXKO and MCL1KO Huh7 cell lines were infected with lentiviruses expressing the indicated BIM-mutants, then cultured in the presence of puromycin. Remaining adherent cells were visualized by Giemsa staining. (C) Deficiency of BCLXL accelerates cell death upon infection with flaviviruses. Parental, BCLXKO and MCL1KO Huh7 cell lines were infected with JEV (MOI = 5), DENV (MOI = 3) or ZIKV (MOI = 1). Cell viability was assessed at the indicated time points. (D) Parental and BCLXKO Huh7 cell lines were infected with JEV (100 FFU), DENV (100 FFU) or ZIKV (500 FFU). At 2 days post-infection, the cells were stained with methylene blue or Giemsa staining. Images are representative of two independent experiments performed with a culture representative of each cell line (A,B,D). The data represent the mean ± SD of three independent experiments performed with a culture representative of each cell line (C).