Fig. 4: Quickfold-predicted RNA structures of the HA cleavage sites and luciferase activity in DF-1 cells.

DF-1 cells were transfected with plasmid. The predicted RNA secondary structures of each HA cleavage site motif and amino acids corresponding to each codon are shown. Nucleotides different from the PARSSR/G-motif are shown in red. a Luciferase activities were expressed relative to the Link30-PARSSR plasmid and compared among the reporter plasmids containing the different linkers, including Link28-PARSSR, Link29-PARSSR, Link29-PSRSSR, Link29-PAKSSR, Link29-PAKSKR, Link29-PAASDR, Link29-PAKKKR, Link29-PAKSKR-NL, and Link29-PAKKKR-NL. Each point on the curve is the mean ± standard deviation from three independent experiments. The independent-samples t test was used for analysis. b The linker 29 and 30 polynucleotides were inserted between a start codon and the firefly luciferase gene lacking its start codon. c Quickfold-prediction RNA structures of the HACS sequences. The predicted RNA secondary structure of rV08-PARSSR (i), rV08-PAKSSR (ii), rV08-PSRSSR (iii), rV08-PAASDR (iv), rV08-PAKSKR (v), rV08-PAKSKR-NL (vi), rV08-PAKKKR (vii), and rV08-PAKKKR-NL (viii) are shown. Nucleotides different from the parental rV08-PARSSR are shown in red.