SK inhibition does not interfere with the viral entry step.

<p>(A and B) MDCK cells were infected with influenza virus (1 MOI) for 1 hr, followed by washing with PBS. Cells were then treated with SKI-II (10 µM) (A) or DMS (5 µM) (B) at 1, 2, 3, or 4 hpi. The expression of viral proteins M1 and M2 was detected by Western blot analysis at 8 hpi. (C and D) MDCK cells were treated with solvent or SKI-II (10 µM) upon influenza virus infection at an MOI of 1. The synthesis of (+) or (-) viral PB2 (C) or NP (D) RNA was analyzed by qPCR at 1 or 2 hpi. The RNA level at 1 hpi was set as 1.0. Values are means ± SEM of three reactions per sample. (E) A549 cells were treated with solvent, DMS (5 µM), or SKI-II (10 µM) and infected with influenza virus at an MOI of 10. The virus was allowed to attach to the cells at 4^°C for 1 hr and the cells were incubated at 37^°C for an additional 1 hr. Western blot analysis was performed to detect internalized viral M1 and GAPDH. The relative intensities for each band of viral M1 are shown.