SR-B1 and LDLR have a redundant role in HCV entry.

(A) Expressions of SR-B1 and LDLR in parental, SR-KO, LD-KO and SR/LD-DKO Huh7 cells were determined by immunoblotting analysis (upper panel). Cells were infected with HCVcc at an MOI of 1, and intracellular HCV RNA levels were determined at 24 h post-infection by qRT-PCR (lower panel). (B) Parental, SR-KO, LD-KO and SR/LD-DKO Huh7 cells were infected with HCVcc at an MOI of 1, and intracellular HCV RNA levels were determined at 24, 48 and 72 h post-infection by qRT-PCR. (C, D) Fluorescence localizations in parental, SR-KO, LD-KO and SR/LD-KO Huh7 cells were observed with a confocal microscope, upon infection with HCVcc at an MOI of 1 at 12, 24, 36, 48 and 60 h post-infection. The frequency is shown as the ratio of infected cells to total cells. (E) SR-B1 and LDLR were exogenously expressed in parental, SR-KO, LD-KO and SR/LD-DKO Huh7 cells by infection with lentiviral vectors. Expressions of SR-B1 and LDLR in these cells were determined by immunoblotting analysis (left panel). Cells were infected with HCVcc at an MOI of 1 and intracellular HCV RNA levels were determined at 24 h post-infection by qRT-PCR (right panel). (F) SR-B1 and LDLR were exogenously expressed in SR/LD-DKO Huh7 cells by infection with different amount of lentiviral vectors. Expressions of SR-B1 and LDLR in these cells were determined by immunoblotting analysis (upper panel). Cells were infected with HCVcc at an MOI of 1 and intracellular HCV RNA levels were determined at 24 h post-infection by qRT-PCR (lower panel). Asterisks indicate significant differences (*P<0.05; **P<0.01) versus the results for control cells.