An RNA virus, designated hepatitis G virus (HGV), was identified from the plasma of a patient with chronic hepatitis. Extension from an immunoreactive complementary DNA clone yielded the entire genome (9392 nucleotides) encoding a polyprotein of 2873 amino acids. The virus is closely related to GB virus C (GBV-C) and distantly related to hepatitis C virus, GBV-A, and GBV-B. HGV was associated with acute and chronic hepatitis. Persistent viremia was detected for up to 9 years in patients with hepatitis. The virus is transfusion-transmissible. It has a global distribution and is present within the volunteer blood donor population in the United States.

No abstract

We determined the nucleotide and deduced amino acid sequence of the 5' terminus of the hepatitis G virus (HGV) genome from isolates of varied geographical origins. Our analysis showed that the putative 5' non-coding region (NCR) contains several blocks of highly conserved sequences that may be useful for the development of a reverse transcriptase-polymerase chain reaction (RT-PCR) assay for detection of HGV RNA. Overall, the degree of conservation within the 669-nucleotide (nt) 5'terminal sequence was found to range from 99.5% to 86% sequence identity. We also showed that the HGV NCR from some isolates contained conserved insertions or deletions that altered the translational reading frames at the 5'-end of the genome, resulting in different sizes of predicted polyproteins encoded by genomes of individual isolates. Specifically, the insertions/deletions affected the size of the peptide preceding the putative first envelope (E1) protein. Phylogenetic analysis of the nucleotide sequences suggested that the isolates examined can be classified into distinct groups that may be useful for studying the molecular evolution of HGV and possible relationships between isolate sequence characteristics and infection patterns.

Two sets of cDNAs encoding mouse synexin were isolated from a liver cDNA library and sequenced. The coding regions of synexin clones show 99% identity. By contrast, the two mouse synexin cDNAs differ in a number of ways in both 5′ and 3′ non-coding regions. The two sets of cDNA encode a polypeptide of 463 amino acid residues which has a deduced molecular mass of 50 kDa. The amino acid sequence of mouse synexin shows a high degree of similarity to both the unique N-terminal domain and the highly conserved C-terminal domain of previously cloned human synexin. Northern-blot analysis using mouse liver polyadenylated RNA revealed two transcripts of 1.8 kb and 2.6 kb, corresponding to group I and group II respectively. Further hybridization analysis using specific sequences from each set of clones showed that the two sizes of mRNAs differ in the length of the 3′ non-coding region which corresponded to the cDNAs. Both mouse liver synexin and recombinant mouse synexin expressed in Escherichia coli reacted after Western-blot analysis with a goat antibody against bovine synexin. Only in the larger group-II cDNAs do we find point mutations leading to amino acid replacements of Ser to Ala at residue 145 in the unique N-terminal domain, and of Ala to Gly at residue 304 in the transition zone between repeats II and III. We conclude from a comparison of mouse, human and Dictyostelium synexins that changes occur predominantly in the hydrophobic N-terminal domain, or, in the C-terminal region at the ends of some predicted alpha-helices, on the hydrophobic face of the amphipathic C-helices, and within a lengthy non-helical domain connecting major repeats II and III.