Tp. Leary et al., THE SEQUENCE AND GENOMIC ORGANIZATION OF A GB VIRUS-A VARIANT ISOLATED FROM CAPTIVE TAMARINS, Journal of General Virology, 78, 1997, pp. 2307-2313
Recently, gene fragments of several novel variants of GB virus A were
isolated from the serum of distinct monkey species that had not been e
xperimentally inoculated with an infectious agent, These variants appe
ared to be species-specific in that sequences isolated within a specie
s were virtually identical, though sequences were strikingly different
when compared between each species. In the present study, the nucleot
ide sequence of one of these variants, GBV-A(lab), was extended to nea
r-genome length, Similar to the other GB viruses, GBV-A(lab) appears t
o encode a single large polyprotein of 2967 amino acids that is post-t
ranslationally cleaved by cellular and viral proteases into the indivi
dual viral proteins, The structural proteins are found at the N-termin
al end of the polyprotein, while the nonstructural proteins are found
at the C teminus. Amino acid sequence comparisons of the large polypro
tein demonstrate that GBV-A(lab) is 74% identical to GBV-A and 48% ide
ntical to GBV-C, sharing only marginal identity with GBV-B and HCV-1 a
t 27%. Examination of the GBV-A,,, polyprotein reveals that structural
motifs are conserved for a protease, a helicase and a replicase, Phyl
ogenetic analysis of the polyprotein confirms previous results that GB
V-A(lab) is a member of the Flaviviridae, distinct from GBV-B and HCV,
though more closely related to GBV-A and GBV-C.