AN INFECTIOUS CDNA COPY OF THE GENOME OF A NON-CARDIOVIRULENT COXSACKIEVIRUS B3 STRAIN - ITS COMPLETE SEQUENCE-ANALYSIS AND COMPARISON TO THE GENOMES OF CARDIOVIRULENT COXSACKIEVIRUSES

The genome of the non-cardiovirulent coxsackievirus B3 (CVB3) strain C VB3/0 was cloned and sequenced to aid in the elucidation of the viral genetic basis for the CVB3 cardiovirulent phenotype. Reverse-transcrib ed sub-genomic complementary DNA (cDNA) fragments were enzymatically a mplified using generic oligonucleotide primers and were assembled as a complete infectious genomic copy (pCVB3-0) downstream of the T7 RNA p olymerase promoter. Positive-strand viral RNA transcribed from pCVB3-0 using T7 RNA polymerase and transfected into HeLa cells produced infe ctious virus (CVB3/0c). No differences in phenotype were observed comp aring growth of CVB3/0c to the parental CVB3/0 in HeLa single-step gro wth curves, virus yields, or plaque size. When inoculated into C3H/HeJ mice, CVB3/0c achieved cardiac titers equivalent to the parental CVB3 /0 and like the parental virus, demonstrated a non-cardiovirulent phen otype. The nucleotide sequence of the cloned CVB3/0 genome was determi ned and compared to the genomes of infectious cDNA clones of cardiovir ulent CVB3 strains. Two consistent differences among nucleotides in no n-translated regions and 8 amino acid differences relative to two well -characterized infectious cDNA copies of genomes from cardiovirulent C VB3 strains were identified.