Coronavirus Transcription: A Perspective
At the VIth International Symposium on Corona and Related Viruses held in Québec, Canada in 1994 we presented a new model for coronavirus transcription to explain how subgenome-length minus strands, which are used as templates for the synthesis of subgenomic mRNAs, might arise by a process involving discontinuous RNA synthesis. The old model explaining subgenomic mRNA synthesis, which was called leader-primed transcription, was based on erroneous evidence that only genome-length negative strands were present in replicative intermediates. To explain the discovery of subgenome-length minus strands, a related model, called the replicon model, was proposed: The subgenomic mRNAs would be produced initially by leader-primed transcription and then replicated into minus-strand templates that would in turn be transcribed into subgenomic mRNAs. We review the experimental evidence that led us to formulate a third model proposing that the discontinuous event in coronavirus RNA synthesis occurs during minus strand synthesis. With our model the genome is copied both continuously to produce minus-strand templates for genome RNA synthesis and discontinuously to produce minus-strand templates for subgenomic mRNA synthesis, and the subgenomic mRNAs do not function as templates for minus strand synthesis, only the genome does.
KeywordsStrand Synthesis Sindbis Virus Minus Strand Mouse Hepatitis Virus Equine Arteritis Virus
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- Lai MMC, Holmes KV (2001) Coronaviridae: The Viruses and Their Replication. In Fields BN, Knipe DM, Howley PM and Griffin DE (eds). Field's Virology, 4th Edition, volume 1, Lippincott, Williams and Wilkins, Philadelphia.Google Scholar
- Manaker RA, Piczak CV, Miller AA, Stanton MF (1961) A hepatitis virus complicating studies with mouse leukemia. Natl Cancer Inst 27:29Google Scholar
- Siddell SG (1995) The Coronaviridae. Plenum Press, New York.Google Scholar