Complete nucleotide sequence of a cytopathic hepatitis A virus strain isolated in Italy

The molecular basis of the cytopathic effect induced in cell culture by some hepatitis A virus (HAV) strains and variants has not been determined. In order to assess the molecular mechanism(s) underlying this particular phenotype the genome of an Italian cytopathic isolate (strain FG) was sequenced from cDNAs obtained by RT-PCR. Sequence analysis revealed the presence of mutations common to either adapted or cytopathic variants of HAV. In particular, amino acid deletions in proteins VP1 and 3A were detected. Expression of protein 3A in E. coli showed that the N-terminal deletion renders this protein toxic to bacteria.