Fig. 2.

Antiviral activities of the synthetic rocaglate CR-31-B (−) against HCoV-229E and MERS-CoV. (A) Western blot analysis of HCoV-229E N protein accumulation (top panel) in cells treated with different enantiomers of CR-31-B. β-Actin (lower panel) was used as a loading control. (B) Total (genomic and subgenomic) viral RNA produced in HCoV-229E-infected MRC-5 cells treated with the two enantiomers of CR-31-B. Relative changes in viral RNA levels were determined by RT-qPCR. The data were normalized to infected but untreated cells as well as GAPDH mRNA using the comparative ΔΔCt method. (C) HCoV-229E and MERS-CoV titers in supernatants collected from infected MRC-5 cells (MOI = 0,1) at 24 hpi. Cells were treated with CR-31-B (−/+) as indicated. Data from three independent experiments were used to calculate EC₅₀ values (2.88 nM for HCoV-229E- and 1.87 nM for MERS-CoV).