Serial passage in mosquito cells of virus with different codons for amino acids 87 and 88 of nsP1.

<p><b>A:</b> Passage of virus with a CUG codon for Leu 87 or a CUG codon (as in SVlm21) and wt nsP4 or SVpzf nsP4. <b>B:</b> Passage of virus with an AGA codon for Arg 87 or a CGU codon (as in SVwt), and wt nsP4 or SVpzf nsP4. Viruses were constructed and passaged as described for Fig. 2.