THE ENTIRE NUCLEOTIDE-SEQUENCES OF 2 GB-VIRUS-C HEPATITIS-G VIRUS ISOLATES OF DISTINCT GENOTYPES FROM JAPAN

Recently, putative viral agents responsible for human non-A to E hepat itis have been independently reported by two groups of investigators a nd designated GB virus C (GBV-C) and hepatitis G virus (HGV), respecti vely, The entire nucleotide sequences were determined for two viral ge nomes isolated from Japanese blood donors with GBV-C RNA. One of them (GT230) had a total genomic length of 9390 nucleotides (nt) with 5' an d 3' untranslated regions of 551 and 313 nt, while the other (GT110) h ad genomic lengths of 9395, 281 and 315 nt, respectively. They both ha d a single long open reading frame, encoding 2842 amino acids (aa) in GT230 and 2933 aa in GT110, Surprisingly, they both lacked a clearly i dentifiable core gene, and possessed the E1/E2 gene with only four pot ential N-linked glycosylation sites, Pairwise comparison and phylogene tic analysis of the entire sequence indicated that the prototype GBV-C and two HGV isolates reported, as well as GT230 and GT110, are the sa me virus possibly of different genotypes, The five GBV-C/HGV isolates were variable up to 13.8% in the genomic nucleotide sequence, and cont ained deletions and insertions within the 5'-terminal 518-593 nt, whic h resulted in four different sizes of predicted polyproteins encoded b y genomes of individual isolates. By contrast, the 3' untranslated reg ion was well conserved, The high degree of sequence conservation withi n this region would favour it as a target for sensitive detection of G BV-C/HGV RNA.