Fig. 6.

Comparison of the inhibitory effects of CR-31-B (−) and Silvestrol on reporter gene expression constructs containing different viral 5′-UTRs. (A) Effects of 5 and 10 nM Silvestrol or CR-31-B (−) on reporter gene expression in the context of 5′-UTRs from coronaviruses HCoV-229E and MERS-CoV as well as EBOV VP30 and VP35. The VP35 5′-terminal hairpin and the VP35 hairpin with (AG)₅ extensions were also analyzed. The predicted RNA secondary structures of the indicated 5′-UTRs are shown. Asterisks mark the positions of purines as part of the polypurine stretch in the VP35 hairpin. (B) The 5′-UTR of HEV and derivatives thereof were analyzed towards their sensitivity against 5 and 10 nM Silvestrol and CR-31-B (−) treatment in a dual luciferase assay. (AG)₁₅ and (AC)₁₅ sequences were used as positive and negative controls, respectively. Predicted RNA secondary structures of the HEV 5′-UTRs are shown. The reporter gene expression data were normalized to the transfection efficiencies and the corresponding DMSO controls. Blue circles indicate the mutated nucleotides in HEVgt3c-G4C and HEVgt3c-G4CC6A. Asterisks mark the positions of purines as part of the polypurine stretch in HEVgt3c-Purine. Standard errors of the mean of at least three independent experiments are shown. MFE = minimal free energy (kcal/mol).