MOLECULAR-CLONING AND NUCLEOTIDE-SEQUENCE DETERMINATION OF 3 ENVELOPEGENES OF CLASSICAL SWINE FEVER VIRUS TAIWAN ISOLATE P97

A strain of classical swine fever virus (CSFV) has been isolated in Ta iwan. The cDNA coding for three envelope glycoproteins E1, E2 and E3 w ere molecularly cloned from purified viral particles using the reverse transcription-polymerase chain reaction (RT-PCR) method and sequence- specific primers. The resulting PCR products (1113 bp for El, 699 bp f or E2 and 567 bp for E3) were cloned into the SmaI site of pUC19 and t hen subjected to DNA sequence analysis. Data showed that nucleotide se quence of the three envelope genes shared a 82-83%, homology with the corresponding genes of three other strains (Alfort, Brescia and Weybri dge). However, the homology of the deduced amino acid sequence was gre ater than 90% among the four strains. The potential asparagine-linked glycosylation sites for E1 (5 sites), E2 (7 sites) and E3 (2 sites) we re conserved. This suggests that the Taiwan p97 strain is distinct fro m other three strains described. The variations may have implications for future vaccine development. The sequence has been submitted to Gen Bank. The accession numbers are U43924 and U03290.