Effect of INSM1-specific siRNA on HSV-1 replication. HEp-2 cells were transfected with siRNA specific for human INSM1 and a scrambled oligomer. At 24 h after transfection, HEp-2 cells were infected with HSV-1(F) (MOI = 1), and total RNA was extracted 6 h after infection. INSM1 mRNA was amplified by RT-PCR as described in Methods. GAPDH was used as a control (A). At 48 h after transfection, cells were infected with HSV-1(F) (MOI = 0.01), and the amount of the major capsid protein VP5 (B) and infectivity (C) were measured at 48 h after infection by Western blotting and plaque assays, respectively. Results of viral titers are shown as mean ± SD. *P < 0.05 (Student's t test) relative to the scrambled control oligomer.