Fig. 7.

Schematic representation of secondary structures which predicted by Mfold program from 5′ UTR swapping mutants. (A) The secondary structure of the 5′- proximal 280 bp of chimeric pTLV8 was displayed, the TRS-L was shaded gray and the ORF1 translational initiation codon was shown in box. “E” denoted European type (type 1), “C” denoted chimeric. (B) The secondary structure of the 5′- proximal 260 bp of chimeric pSHSP5 was shown, the TRS-L was also shaded gray and “AUG” was shown in box. “N” indicated North American type (type 2), “C′” also indicated chimeric.