Role of RNA Regulatory Elements in Dengue Virus Replication

GAMARNIK A., FILOMATORI C., LODEIRO F., ALVAREZ D. AND IGLESIAS G.

Brasil

Congreso; First Pan-American Dengue Research Network Meeting; 2008

Title: Role of RNA Regulatory Elements in Dengue Virus Replication Authors: Gamarnik A., Filomatori C., Lodeiro F., Alvarez D. and Iglesias G. Institution: Fundación Instituto Leloir, Address: Av. Patricias Argentinas 435, Buenos Aires, Argentina E-Mail: agamarnik@leloir.org.ar   The single plus stranded RNA genome of dengue and other flaviviruses is amplified in the infected cell by a two-step process. First, the RNA dependent RNA polymerase (RdRp), encoded in the viral protein NS5, makes a complementary strand with negative polarity, which then, serves as a template to copy multiple viral genomes. Molecular details of how the viral RdRp recognizes and specifically amplifies flavivirus genomes remain unclear. We have recently proposed a model for dengue virus RNA amplification that involves a promoter element for polymerase activity at the 5’ end of the genome and cyclization of the viral genome. Now, we are studying how these cis-acting RNA elements participate in the process. Using in vitro RNA polymerase assays and infectious viral RNAs, the structural elements required for promoter activity and viral replication were defined. These elements were found to be conserved among different members of the Flavivirus genus, providing evidence for a common mechanism of promoter mediated RNA synthesis. In addition, mutations within the mapped element involved in genome cyclization resulted in revertant viruses that reconstituted alternative secondary and tertiary structures. These results suggest that fluctuating conformation, between linear and circular forms of the genome, are necessary for viral replication.