Characterization of internal ribosomal entry sites of Triatoma virus.
Triatoma virus (TrV) belongs to a new family of RNA viruses known as Dicistroviridae. Nucleotide sequence comparisons between different dicistroviruses allowed two putative internal ribosomal entry sites (IRESs) in the TrV RNA to be defined: the 5'UTR IRES of 548 nt and the intergenic region (IGR) IRES of 172 nt. Using monocistronic and bicistronic RNAs, it was shown that the TrV genome contains two functional IRESs that mediate translation initiation in a cap-independent manner. In addition, it was found that the two TrV IRESs were able to direct efficient translation of reporter genes in microinjected Xenopus oocytes, suggesting minimum requirements for host factors. The IGR IRES begins with a non-canonical CUC; however, mutations of this triplet to AUG or CCU did not impair IRES function, indicating that the CUC is not essential for the initiation process. Furthermore, translation efficiency from two TrV IRESs was differentially modulated by IFN-alpha and viral infection.
Czibener
Cecilia
C
Fundación Instituto Leloir, Avenida Patricias Argentinas 435, Buenos Aires 1405, Argentina.
Alvarez
Diego
D
Fundación Instituto Leloir, Avenida Patricias Argentinas 435, Buenos Aires 1405, Argentina.
Scodeller
Eduardo
E
Centro de Virología Animal CEVAN, Serrano 669, 3er piso, Buenos Aires 1414, Argentina.
Gamarnik
Andrea V
AV
Fundación Instituto Leloir, Avenida Patricias Argentinas 435, Buenos Aires 1405, Argentina.
D020121:5' Untranslated Regions / Q000502:physiology; D000818:Animals; D002460:Cell Line; D006224:Cricetinae; D009033:Culicidae; D021901:DNA, Intergenic / Q000502:physiology; D017930:Genes, Reporter / Q000502:physiology; D016898:Interferon-alpha / Q000494:pharmacology; D008156:Luciferases / Q000378:metabolism; D014176:Protein Biosynthesis; D012328:RNA Viruses / Q000378:metabolism*; D012367:RNA, Viral / Q000378:metabolism*; D012270:Ribosomes / Q000378:metabolism / Q000821:virology; D014224:Triatoma / Q000821:virology*
D020121:5' Untranslated Regions; D021901:DNA, Intergenic; D016898:Interferon-alpha; D012367:RNA, Viral; D008156:Luciferases