Transcription, Replication, Recombination, and Engineering of Coronavirus Genes

  • Michael M. C. Lai
Part of the Advances in Experimental Medicine and Biology book series (AEMB, volume 380)


When one discusses coronavirus RNA synthesis, several unique features of coro-navirus RNAs immediately come to mind1: the extraordinary length (27’31 kb) of the RNA genome, the subgenomic mRNAs with a leader RNA derived from the 5′-end of the genome, and the presence of common sequences between the 3′-end of the leader RNA and the sequence (intergenic sequence, IG) preceding each gene (Figure 1). These characteristics indicate that coronavirus RNA synthesis has to be discontinuous, so that the leader RNA can be joined with mRNAs. This feature, coupled with several unique phenomena associated with coronavirus replication, e.g., high frequency of RNA recombination2 and rapid generation and evolution of defective interfering (DI) RNA3, suggests that coronavirus RNA polymerase is probably nonprocessive, being able to jump between different RNA regions and RNA molecules during synthesis. This discontinuous nature of coronavirus RNA synthesis appears to contrast with another requisite function of RNA polymerase, i.e., faithful replication of the long RNA genome. These seemingly conflicting demands on coronavirus RNA polymerase suggest that the coronavirus polymerase is very versatile and the mechanism of coronavirus RNA synthesis is unique.


Internal Ribosomal Entry Site mRNA Transcription Mouse Hepatitis ViruS Defective Interfere Internal Ribosomal Entry Site Sequence 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


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Copyright information

© Springer Science+Business Media New York 1995

Authors and Affiliations

  • Michael M. C. Lai
    • 1
  1. 1.Howard Hughes Medical Institute and Department of Molecular MicrobiologyUniversity of Southern California School of MedicineLos AngelesUSA

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