title: Molecular analysis of the factorless internal ribosome entry site in Cricket Paralysis virus infection.
abstract: The dicistrovirus Cricket Paralysis virus contains a unique dicistronic RNA genome arrangement, encoding two main open reading frames that are driven by distinct internal ribosome entry sites (IRES). The intergenic region (IGR) IRES adopts an unusual structure that directly recruits the ribosome and drives translation of viral structural proteins in a factor-independent manner. While structural, biochemical, and biophysical approaches have provided mechanistic details into IGR IRES translation, these studies have been limited to in vitro systems and little is known about the behavior of these IRESs during infection. Here, we examined the role of previously characterized IGR IRES mutations on viral yield and translation in CrPV-infected Drosophila S2 cells. Using a recently generated infectious CrPV clone, introduction of a subset of mutations that are known to disrupt IRES activity failed to produce virus, demonstrating the physiological relevance of specific structural elements within the IRES for virus infection. However, a subset of mutations still led to virus production, thus revealing the key IRES-ribosome interactions for IGR IRES translation in infected cells, which highlights the importance of examining IRES activity in its physiological context. This is the first study to examine IGR IRES translation in its native context during virus infection.
authors.affiliation: Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver BC, Canada.
authors.forename: Craig H
authors.initials: CH
authors.lastname: Kerr
authors.affiliation: Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver BC, Canada.
authors.forename: Zi Wang
authors.initials: ZW
authors.lastname: Ma
authors.affiliation: Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver BC, Canada.
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Jang
authors.affiliation: Department of Microbiology, University of Alabama at Birmingham, Birmingham, Alabama, USA.
authors.forename: Sunnie R
authors.initials: SR
authors.lastname: Thompson
authors.affiliation: Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver BC, Canada.
authors.forename: Eric
authors.initials: E
authors.lastname: Jan
mesh_terms: D000818:Animals; D001483:Base Sequence; D002460:Cell Line; D056629:Dicistroviridae / Q000235:genetics*; D004331:Drosophila melanogaster; D016679:Genome, Viral; D000067556:Internal Ribosome Entry Sites; D009154:Mutation; D014176:Protein Biosynthesis; D012367:RNA, Viral / Q000235:genetics*; D015678:Viral Structural Proteins / Q000096:biosynthesis / Q000235:genetics; D014779:Virus Replication
chemical_list: D000067556:Internal Ribosome Entry Sites; D012367:RNA, Viral; D015678:Viral Structural Proteins