In vivo analysis of the 3' untranslated region of the hepatitis C virus after in vitro mutagenesis of an infectious cDNA clone - PubMed (original) (raw)

In vivo analysis of the 3' untranslated region of the hepatitis C virus after in vitro mutagenesis of an infectious cDNA clone

M Yanagi et al. Proc Natl Acad Sci U S A. 1999.

Abstract

Large sections of the 3' untranslated region (UTR) of hepatitis C virus (HCV) were deleted from an infectious cDNA clone, and the RNA transcripts from seven deletion mutants were tested sequentially for infectivity in a chimpanzee. Mutants lacking all or part of the 3' terminal conserved region or the poly(U-UC) region were unable to infect the chimpanzee, indicating that both regions are critical for infectivity in vivo. However, the third region, the variable region, was able to tolerate a deletion that destroyed the two putative stem-loop structures within this region. Mutant VR-24 containing a deletion of the proximal 24 nt of the variable region of the 3' UTR was viable in the chimpanzee and seemed to replicate as well as the undeleted parent virus. The chimpanzee became viremic 1 week after inoculation with mutant VR-24, and the HCV genome titer increased over time during the early acute infection. Therefore, the poly(U-UC) region and the conserved region, but not the variable region, of the 3' UTR seem to be critical for in vivo infectivity of HCV.

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Figures

Figure 1

(On the opposite page.) The 3′ UTR deletion mutants of an infectious cDNA clone of HCV (pCV-H77C; ref. ; figure adapted from Kolykhalov et al., ref. 6). The deleted sequences are shown in black bars. Sequences are shown starting at position 9,363 in the NS5B. The 3′ UTR of H77C has 225 nt, consisting of the ORF stop codon, a short sequence of 40 nt (variable region), a poly(U–UC) region of 81 nt, and a 3′ terminal sequence of 101 nt (conserved region). Sequences in the 3′ end of NS5B and in the variable region of the 3′ UTR could potentially form two stem–loop structures, and sequences of the conserved region of the 3′ UTR could potentially form three stem–loop structures.

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In vivo analysis of the 3' untranslated region of the hepatitis C virus after in vitro mutagenesis of an infectious cDNA clone - PubMed (original) (raw)