MOLECULAR-CLONING AND CHARACTERIZATION OF A GB VIRUS-C ISOLATE FROM APATIENT WITH NON-A-E HEPATITIS

Recently, the isolation of a novel virus, GB virus C (GBV-C), associat ed with cryptogenic hepatitis has been reported. Following the molecul ar cloning of this virus genome, it became apparent that the genomic s equence did not encode a protein resembling a nucleocapsid or core-lik e protein similar to those observed in other flaviviruses, pestiviruse s, hepatitis C virus (HCV) and GB virus B. Similar findings were subse quently observed in the cloning of two viral genomes representing isol ates of GBV-C, namely hepatitis G virus (HGV). To verify the presence or absence of a viral nucleocapsid protein, identify conserved protein motifs and determine the overall genomic variability, an additional v irus isolate has been characterized. Here we report the full-length ge nomic sequence of GBV-C(EA), isolated from an East African suffering f rom acute non-A-E hepatitis, GBV-C(EA) was compared with the prototype West African isolate (GBV-C) and the two HGV isolates from the United States. The analyses demonstrate several characteristics of these nov el viruses. (1) The degree of variability within the 5' nontranslated region (NTR) approximates that observed between HCV isolates. (2) The nucleotide sequence of the coding region and the 3' NTR is highly cons erved between these isolates, in contrast to the extensive variability observed between HCV isolates from distinct geographical locations. ( 3) There is a high degree of amino acid conservation across the precur sor polyproteins of these isolates; most striking is the lack of 'hype rvariable' regions within the envelope proteins. (4) There appears to be no nucleocapsid protein near the amino terminus of the GBV-C/HGV po lyproteins.