Fig. 4.
Analysis of TBEV mutants expressing the 3Cpro cleavage site and the 3Cpro on the same construct. (a) Schematic of TBEV full-length mutants with the PV-2AΔ3 insertion within the C-terminal region of protein C, the heparan sulphate mutation in E and the 3Cpro. (b) IF analysis of viral protein expression and viral infectivity. BHK-21 cells were transfected with mutant RNAs or were mock transfected, and viral protein expression was detected by IF with the polyclonal serum 1 day post-transfection (top). Supernatants harvested 1 day post-electroporation were also transferred onto fresh BHK-21 cells (arrows), and viral protein expression monitored by IF 1 day post-infection (bottom).