FIG. 4.

Nucleotide sequences of the long stem-loop structures of 3′SLs present in WNmutC2 (A) and WNmutA2 (B) RNAs are depicted in comparison to WNmutC1 and WNmutA1 3′SLs, respectively. Boldface type indicates nucleotides derived from the wt WN virus 3′SL sequence. Roman type, nucleotides derived from the wt DEN2 3′SL sequence. The 5-bp TEF-binding domain in C1 and A2 RNAs is indicated by brackets and an asterisk. Nucleotides included in the 11-bp ds segment previously shown to be required for DEN2 virus replication (42) are underlined. Arrows indicate that the TEF-binding domain was deleted from the C1 3′SL to generate the C2 3′SL. Similarly, arrows indicate that the TEF-binding domain was inserted into the A1 3′SL where shown in order to generate the A2 3′SL. Dashed lines delineate both the boundary between top and bottom portions of the WN virus 3′SL and the boundary between WN and DEN2 (DN) nucleotide sequences. (+), mutant RNA replicated efficiently after transfection of BHK (and Vero) cells compared to wt RNA; (−), transfected cells remained negative by IFA for 20 days posttransfection.