title: Hepatitis C virus IRES efficiency is unaffected by the genomic RNA 3'NTR even in the presence of viral structural or non-structural proteins.
abstract: Hepatitis C virus (HCV) translation is mediated by an IRES structure. Instead of a poly(A) tail, the 3' end of the genome contains a tripartite 3'NTR composed of a non-conserved region, a polypyrimidine tract and a highly conserved stretch of 98 nt, termed the 3'X region. Using a set of bicistronic recombinant DNA constructs expressing two reporter genes separated by the HCV IRES, it was determined whether the HCV 3'NTR sequence, in the presence or absence of HCV proteins, played a role in the efficiency of HCV IRES-dependent translation ex vivo. Bicistronic expression cassettes were transfected into hepatic and non-hepatic cell lines. These results show that neither the entire 3'NTR nor the 3'X sequence alters IRES-dependent translation efficiency, whatever the cell line tested. A potential effect of the 3'NTR on IRES-dependent translation in the presence of HCV proteins was investigated further. Neither non-structural nor structural HCV proteins had any effect on the efficiency of IRES in this system. In addition, in order to mimic HCV genome organization, monocistronic expression cassettes containing the IRES and a Core-DsRed fusion gene were constructed with or without the 3'NTR. In this context, no effect of the 3'NTR on IRES translation efficiency was observed, even in the presence of HCV proteins. These data demonstrate that HCV translation is not modulated by the viral genomic 3'NTR sequence, even in the presence of HCV structural or non-structural proteins.
authors.affiliation: INSERM U544, Institut de Virologie, 3 rue Koeberlé, 67000 Strasbourg, France.
authors.forename: Isabelle
authors.initials: I
authors.lastname: Imbert
authors.affiliation: INSERM U544, Institut de Virologie, 3 rue Koeberlé, 67000 Strasbourg, France.
authors.forename: Maria
authors.initials: M
authors.lastname: Dimitrova
authors.affiliation: INSERM U544, Institut de Virologie, 3 rue Koeberlé, 67000 Strasbourg, France.
authors.forename: François
authors.initials: F
authors.lastname: Kien
authors.affiliation: INSERM U544, Institut de Virologie, 3 rue Koeberlé, 67000 Strasbourg, France.
authors.forename: Marie Paule
authors.initials: MP
authors.lastname: Kieny
authors.affiliation: INSERM U544, Institut de Virologie, 3 rue Koeberlé, 67000 Strasbourg, France.
authors.forename: Catherine
authors.initials: C
authors.lastname: Schuster
mesh_terms: D020413:3' Untranslated Regions; D000256:Adenoviridae / Q000235:genetics; D002460:Cell Line; D016679:Genome, Viral; D016174:Hepacivirus / Q000235:genetics* / Q000378:metabolism; D006801:Humans; D010957:Plasmids / Q000235:genetics; D012367:RNA, Viral / Q000235:genetics*; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D014616:Vaccinia virus / Q000235:genetics; D017361:Viral Nonstructural Proteins / Q000235:genetics / Q000378:metabolism; D015678:Viral Structural Proteins / Q000235:genetics / Q000378:metabolism
chemical_list: D020413:3' Untranslated Regions; D012367:RNA, Viral; D011994:Recombinant Proteins; D017361:Viral Nonstructural Proteins; D015678:Viral Structural Proteins