Promotion of Viral IRES-Mediated Translation Initiation under Mild Hypothermia: e0126174

• Published in: PloS one Vol. 10; no. 5
• Main Authors: Licursi, Maria, Carmona-Martinez, Ricardo A, Razavi, Seyd, Hirasawa, Kensuke
• Format: Journal Article
• Language: English
• Published: 01.05.2015
• Subjects: Encephalomyocarditis virus; Foot-and-mouth disease virus; Hepatitis C virus; Human rhinovirus; Poliovirus
• ISSN: 1932-6203
• DOI: 10.1371/journal.pone.0126174

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 degree C), we observed increases in the efficiency of translation initiation by HCV and HRV IRES elements compared to translation initiation at 37 degree 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 degree C to 30 degree C. Taken together, this study demonstrates that efficiency of translation initiation by some viral IRES elements is temperature dependent.