title: Inhibition of hepatitis C virus IRES-mediated translation by small RNAs analogous to stem-loop structures of the 5'-untranslated region.
abstract: Translation of the hepatitis C virus (HCV) RNA is mediated by the interaction of ribosomes and cellular proteins with an internal ribosome entry site (IRES) located within the 5'-untranslated region (5'-UTR). We have investigated whether small RNA molecules corresponding to the different stem-loop (SL) domains of the HCV IRES, when introduced in trans, can bind to the cellular proteins and antagonize their binding to the viral IRES, thereby inhibiting HCV IRES-mediated translation. We have found that a RNA molecule corresponding to SL III could efficiently inhibit HCV IRES-mediated translation in a dose-dependent manner without affecting cap-dependent translation. The SL III RNA was found to bind to most of the cellular proteins which interacted with the HCV 5'-UTR. A smaller RNA corresponding to SL e+f of domain III also strongly and selectively inhibited HCV IRES-mediated translation. This RNA molecule interacted with the ribosomal S5 protein and prevented the recruitment of the 40S ribosomal subunit. This study reveals valuable insights into the role of the SL structures of the HCV IRES in mediating ribosome entry. Finally, these results provide a basis for developing anti-HCV therapy using small RNA molecules mimicking the SL structures of the 5'-UTR to specifically block viral RNA translation.
authors.affiliation: Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore 560012, India.
authors.forename: Partho Sarothi
authors.initials: PS
authors.lastname: Ray
authors.forename: Saumitra
authors.initials: S
authors.lastname: Das
mesh_terms: D020121:5' Untranslated Regions; D001483:Base Sequence; D002460:Cell Line; D016174:Hepacivirus / Q000187:drug effects / Q000235:genetics* / Q000502:physiology; D006801:Humans; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D014176:Protein Biosynthesis / Q000187:drug effects*; D021382:Protein Sorting Signals; D012313:RNA / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology*; D012367:RNA, Viral / Q000037:antagonists & inhibitors* / Q000737:chemistry / Q000378:metabolism; D012269:Ribosomal Proteins / Q000378:metabolism; D012270:Ribosomes / Q000187:drug effects; D014764:Viral Proteins / Q000378:metabolism; D014779:Virus Replication / Q000187:drug effects
chemical_list: D020121:5' Untranslated Regions; D021382:Protein Sorting Signals; D012367:RNA, Viral; D012269:Ribosomal Proteins; D014764:Viral Proteins; C030831:ribosomal protein S5; D012313:RNA