Recombinant virus genomes were amplified and sequenced in the
regions that were mutagenized, that is, from the 3 end of the spike gene into the
5 end of the EGFP coding region. Reverse transcriptase-mediated PCR (RTPCR)
amplification was carried out, using as templates cytoplasmic RNA extracted
from virus-infected L2 cells and the primers FIJ81 and RIJ84