title: Temporal Regulation of Distinct Internal Ribosome Entry Sites of the Dicistroviridae Cricket Paralysis Virus.
abstract: Internal ribosome entry is a key mechanism for viral protein synthesis in a subset of RNA viruses. Cricket paralysis virus (CrPV), a member of Dicistroviridae, has a positive-sense single strand RNA genome that contains two internal ribosome entry sites (IRES), a 5'untranslated region (5'UTR) and intergenic region (IGR) IRES, that direct translation of open reading frames (ORF) encoding the viral non-structural and structural proteins, respectively. The regulation of and the significance of the CrPV IRESs during infection are not fully understood. In this study, using a series of biochemical assays including radioactive-pulse labelling, reporter RNA assays and ribosome profiling, we demonstrate that while 5'UTR IRES translational activity is constant throughout infection, IGR IRES translation is delayed and then stimulated two to three hours post infection. The delay in IGR IRES translation is not affected by inhibiting global translation prematurely via treatment with Pateamine A. Using a CrPV replicon that uncouples viral translation and replication, we show that the increase in IGR IRES translation is dependent on expression of non-structural proteins and is greatly stimulated when replication is active. Temporal regulation by distinct IRESs within the CrPV genome is an effective viral strategy to ensure optimal timing and expression of viral proteins to facilitate infection.
authors.affiliation: Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, BC V6T 1Z3, Canada. anthony.k.khong@gmail.com.
authors.forename: Anthony
authors.initials: A
authors.lastname: Khong
authors.affiliation: Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, BC V6T 1Z3, Canada. jbonderoff@gmail.com.
authors.forename: Jennifer M
authors.initials: JM
authors.lastname: Bonderoff
authors.affiliation: Medical Research Council Toxicology Unit, Leicester LE1 9HN, UK. rvs3@leicester.ac.uk.
authors.forename: Ruth V
authors.initials: RV
authors.lastname: Spriggs
authors.affiliation: Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, BC V6T 1Z3, Canada. etammpere@gmail.com.
authors.forename: Erik
authors.initials: E
authors.lastname: Tammpere
authors.affiliation: Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, BC V6T 1Z3, Canada. kerrc15@gmail.com.
authors.forename: Craig H
authors.initials: CH
authors.lastname: Kerr
authors.affiliation: Medical Research Council Toxicology Unit, Leicester LE1 9HN, UK. tomjacksonhk@gmail.com.
authors.forename: Thomas J
authors.initials: TJ
authors.lastname: Jackson
authors.affiliation: Medical Research Council Toxicology Unit, Leicester LE1 9HN, UK. aew5@le.ac.uk.
authors.forename: Anne E
authors.initials: AE
authors.lastname: Willis
authors.affiliation: Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, BC V6T 1Z3, Canada. ej@mail.ubc.ca.
authors.forename: Eric
authors.initials: E
authors.lastname: Jan
mesh_terms: D020121:5' Untranslated Regions; D000818:Animals; D056629:Dicistroviridae / Q000235:genetics* / Q000378:metabolism; D004330:Drosophila / Q000821:virology; D015967:Gene Expression Regulation, Viral; D000067556:Internal Ribosome Entry Sites; D016366:Open Reading Frames; D014176:Protein Biosynthesis; D012367:RNA, Viral / Q000235:genetics / Q000378:metabolism; D014764:Viral Proteins / Q000235:genetics / Q000378:metabolism
chemical_list: D020121:5' Untranslated Regions; D000067556:Internal Ribosome Entry Sites; D012367:RNA, Viral; D014764:Viral Proteins
keywords: IRES; dicistrovirus; ribosome; translation; virus