FIG 1.

HSP90 activity is required for efficient growth of MeV. (A to E) Inhibition of HSP90 activity with geldanamycin, 17-DMAG, or NVP-AUY922 abolishes MeV growth. Vero cells were infected with a recombinant MeV coding for GFP as a viral reporter at an MOI of 0.5 and treated with geldanamycin (A, B), 17-DMAG (C, D), or NVP-AUY922 (E) or not treated. Viral infection was assessed at 24 hpi by measuring GFP expression by flow cytometry (A, C, E) or by measuring MeV production (B, D). 17-DMAG or NVP-AUY922 treatment did not kill cells during 24 h of treatment, as shown by the limited reduction of cellular reductase activity observed at high concentrations with alamarBlue reagent (F, G). (H) Reduction of HSP90 expression by siRNA reduces MeV growth in simian Vero and human HeLa cells. Vero and HeLa cells were transfected with a siRNA targeting the HSP90 mRNA (siHSP90) or a control siRNA (siCtrl) and infected 1 day later with MeV (Schwarz strain) at an MOI of 1. The expression of HSP90 and MeV N protein was assessed by Western blotting (top) at 1 day postinfection, and the impact on MeV production was assessed by the TCID₅₀ titration method (bottom).