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Different Mechanisms of Homologous and Nonhomologous Recombination in Brome Mosaic Virus, a Model Plant RNA Virus

  • Jozef J. Bujarski
Conference paper
  • 56 Downloads

Abstract

Brome mosaic bromovirus, a tripartite, positive-stranded RNA virus of plants, can generate both homologous and nonhomologous intersegment RNA recombinants in vivo. The use of specially designed BMV RNA recombination vectors has demonstrated that recombination signals in the RNAs were different for these two recombination types. Specifically, nonhomologous recombination requires the formation of local double-stranded regions between the recombining RNAs while homologous recombination is facilitated by AU-rich sequences in conjunction with upstream GC-rich regions, common in the RNA substrates. These features most likely reflect different mechanisms involved in homologous and nonhomologous crossovers for this RNA virus.

To study if BMV replicase is involved in RNA recombination, viable mutants in both la and 2a replicase polypeptides were tested. Specifically, mutations within the helicase domain of la affected the location of crossover sites in nonhomologous recombination. This demonstrates that la protein is involved in nonhomologous recombination, most likely in unwinding double-stranded regions between the recombining RNAs. Mutations in the core domain of 2a, the RNA polymerase component, have reduced nonhomologous recombination below the level of detection, without affecting noticeably homologous recombination. All these observations confirm the existence of differences in the molecular mechanisms of both recombination types.

Keywords

Homologous Recombination Helicase Domain Junction Site Brome Mosaic Virus Recombination Type 
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-Verlag Berlin Heidelberg 1997

Authors and Affiliations

  • Jozef J. Bujarski
    • 1
  1. 1.Plant Molecular Biology Center and the Department of Biological SciencesNorthern Illinois UniversityDeKalbUSA

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