title: Promotion of Viral IRES-Mediated Translation Initiation under Mild Hypothermia.
abstract: Internal ribosome entry site (IRES)-mediated translation is an essential replication step for certain viruses. As IRES-mediated translation is regulated differently from cap-dependent translation under various cellular conditions, we sought to investigate whether temperature influences efficiency of viral IRES-mediated translation initiation by using bicistronic reporter constructs containing an IRES element of encephalomyocarditis virus (EMCV), foot-and-mouth disease virus (FMDV), hepatitis C virus (HCV), human rhinovirus (HRV) or poliovirus (PV). Under mild hypothermic conditions (30 and 35°C), we observed increases in the efficiency of translation initiation by HCV and HRV IRES elements compared to translation initiation at 37°C. The promotion of HRV IRES activity was observed as early as 2 hours after exposure to mild hypothermia. We also confirmed the promotion of translation initiation by HRV IRES under mild hypothermia in multiple cell lines. The expression levels and locations of polypyrimidine tract-binding protein (PTB) and upstream of N-Ras (unr), the IRES trans-acting factors (ITAFs) of HCV and HRV IRES elements, were not modulated by the temperature shift from 37°C to 30°C. Taken together, this study demonstrates that efficiency of translation initiation by some viral IRES elements is temperature dependent.
authors.affiliation: Division of BioMedical Science, Faculty of Medicine, Memorial University of Newfoundland, 300 Prince Philip Dr., St. John's, NL, A1B 3V6, Canada.
authors.forename: Maria
authors.initials: M
authors.lastname: Licursi
authors.affiliation: Division of BioMedical Science, Faculty of Medicine, Memorial University of Newfoundland, 300 Prince Philip Dr., St. John's, NL, A1B 3V6, Canada.
authors.forename: Ricardo A
authors.initials: RA
authors.lastname: Carmona-Martinez
authors.affiliation: Division of BioMedical Science, Faculty of Medicine, Memorial University of Newfoundland, 300 Prince Philip Dr., St. John's, NL, A1B 3V6, Canada.
authors.forename: Seyd
authors.initials: S
authors.lastname: Razavi
authors.affiliation: Division of BioMedical Science, Faculty of Medicine, Memorial University of Newfoundland, 300 Prince Philip Dr., St. John's, NL, A1B 3V6, Canada.
authors.forename: Kensuke
authors.initials: K
authors.lastname: Hirasawa
mesh_terms: D000818:Animals; D002460:Cell Line; D006801:Humans; D007035:Hypothermia / Q000235:genetics*; D000067556:Internal Ribosome Entry Sites; D051379:Mice; D014176:Protein Biosynthesis; D014780:Viruses / Q000235:genetics*
chemical_list: D000067556:Internal Ribosome Entry Sites