Characterization of Internal Ribosomal Entry Sites of Triatoma Virus

CECILIA CZIBENER, EDUARDO SCODELLER, AND ANDREA GAMARNIK

JOURNAL OF GENERAL VIROLOGY

Año: 2005 vol. 86 p. 2275 - 2280

0022-1317

Triatoma virus (TrV) belongs to a new family of RNA viruses known as Dicistroviridae. Nucleotide sequence comparisons between different dicistroviruses allowed us to define two putative IRESes in the TrV RNA: the 5’UTR IRES of 548 nt and the intergenic (IG) IRES of 172 nt. Using monocistronic and bicistronic RNAs, we show that the TrV genome contains two functional IRESes that mediate translation initiation in a cap-independent manner. In addition, we observed that the two IRESes of TrV are able to direct efficient translation of reporter genes in microinjected Xenopus oocytes, suggesting minimum requirements of host factors. The IG IRES begins with a noncognate 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 efficiencies from two TrV IRESes was differentially modulated by IFN-a and viral infection.