FIG 7.

Defects in cap-independent translation attenuate DTMUV replicons and viruses. (A and C) Schematic presentation of DTMUV replicons (A) and genomes (C) harboring mutations in the 3′ UTR. WT residues and their positions in the genome of DTMUV are shown; mutated residues are indicated in red. C₃₄, region encoding a truncated capsid protein; E₃₀, region encoding 30 C-terminal residues of E glycoprotein; FMDV, foot-and-mouth disease virus; NLuc, region encoding the nanoluciferase reporter. The intron shown in panel C is present only in the icDNA plasmid and is removed by splicing upon viral rescue. (B) BHK-21 cells were transfected with the indicated plasmids. At 12, 24, 48, and 72 h p.t., the cells were lysed, and NLuc activities were measured. The data are presented as means plus SD (n = 3). (D) BHK-21 cells were transfected with pCMV-icDTMUV, pCMV-icDTMUV-DB2mut3, or pCMV-icDTMUV-SLmut5. The rescue of the recombinant viruses at 48 and 72 h p.t. was assessed using a mouse anti-DTMUV polyclonal antibody.