Volume 11, Number 7, July 2005

Norovirus Recombination in ORF1/ORF2 Overlap

Rowena A. Bull,* Grant S. Hansman,† Leighton E. Clancy,*‡ Mark M. Tanaka,* William D. Rawlinson,*‡ and Peter A. White*
*University of New South Wales, Sydney, New South Wales, Australia; †University of Tokyo, Tokyo, Japan; and ‡Prince of Wales Hospital, Randwick, New South Wales, Australia

Figure 3. A simple mechanism for recombination in norovirus. 1) RNA transcription by the RNA-dependent RNA polymerase (RdRp) (gray circle) generates a negative-stranded intermediate (dashed line). 2) Binding of the RdRp to the almost identical RNA promoter sequences (filled boxes) generates positive-stranded (straight line) genomes and subgenomic RNA. 3) These templates direct RNA synthesis from the 3´ end that leads to the generation of both a full-length negative genome and a negative subgenomic RNA species. 4) Recombination occurs when the enzyme initiates positive-strand synthesis at the 3´ end of the full-length negative strand, stalls at the subgenomic promoter, and then template switches to an available negative subgenomic RNA species generated by a co-infecting virus. The net result is a recombinant virus that has acquired new open reading frame (ORF)2 and ORF3 sequences.

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This page last reviewed June 10, 2005

Emerging Infectious Diseases Journal
National Center for Infectious Diseases
Centers for Disease Control and Prevention