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| Subject Categories: RNA | Microbiology & Pathogens |
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| The EMBO Journal
(2007) 26, 5120–5130, doi:10.1038/sj.emboj.7601931 Published online 22 November 2007 |
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| Uncoupling RNA virus replication from transcription via the polymerase: functional and evolutionary insights |
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| Baodong Wu and K Andrew White |
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Department of Biology, York University, Toronto, Ontario, Canada To whom correspondence should be addressed K Andrew White, Department of Biology, York University, 4700 Keele Street, Toronto, Ontario, Canada M3J 1P3. Tel.: +1 416 736 5243; Fax: +1 416 736 5698; E-mail: kawhite@yorku.ca Received 23 July 2007; Accepted 29 October 2007; Published online 22 November 2007. |
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| Abstract |
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| Many eukaryotic positive-strand RNA viruses transcribe subgenomic (sg) mRNAs that are virus-derived messages that template the translation of a subset of viral proteins. Currently, the premature termination (PT) mechanism of sg mRNA transcription, a process thought to operate in a variety of viruses, is best understood in tombusviruses. The viral RNA elements involved in regulating this mechanism have been well characterized in several systems; however, no corresponding protein factors have been identified yet. Here we show that tombusvirus genome replication can be effectively uncoupled from sg mRNA transcription in vivo by C-terminal modifications in its RNA-dependent RNA polymerase (RdRp). Systematic analysis of the PT transcriptional pathway using viral genomes harboring mutant RdRps revealed that the C-terminus functions primarily at an early step in this mechanism by mediating both efficient and accurate production of minus-strand templates for sg mRNA transcription. Our results also suggest a simple evolutionary scheme by which the virus could gain or enhance its transcriptional activity, and define global folding of the viral RNA genome as a previously unappreciated determinant of RdRp evolution. |
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| Keywords: gene expression, protein evolution, RNA-dependent RNA polymerase, subgenomic mRNA, tombusvirus |
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Top of page MORE ARTICLES LIKE THISThese links to content published by NPG are automatically generated RESEARCHThe EMBO Journal Article A replication silencer element in a plus-strand RNA virus The EMBO Journal Article (15 Oct 2003) A replication silencer element in a plus-strand RNA virus The EMBO Journal Article (15 Oct 2003) A complex network of RNA?RNA interactions controls subgenomic mRNA transcription in a tombusvirus The EMBO Journal Article (18 Aug 2004) Discontinuous and non-discontinuous subgenomic RNA transcription in a nidovirus The EMBO Journal Article (01 Dec 2002) |
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