IIBBA   05544
INSTITUTO DE INVESTIGACIONES BIOQUIMICAS DE BUENOS AIRES
Unidad Ejecutora - UE
artículos
Título:
Functional Analysis of Dengue Virus Cyclization Sequences Located at the 5' and 3' UTRs
Autor/es:
DIEGO ALVAREZ, CLAUDIA FILOMATORI, AND ANDREA GAMARNIK
Revista:
VIROLOGY
Referencias:
Año: 2008 vol. 375 p. 223 - 235
ISSN:
0042-6822
Resumen:
Flavivirus RNA replication involves cyclization of the viral genome. A model for this process includes a promoter element at the 5 end of the genome and long-range RNA-RNA interactions. Two pairs of complementary sequences present at the ends of the viral RNA, known as 5-3CS and 5-3UAR, have been proposed to be involved in dengue virus genome cyclization. The requirement of 5-3CS complementarity for viral replication has been experimentally demonstrated for dengue and other mosquito borne flaviviruses. Here, we performed a functional analysis to study the role of 5-3 UAR sequences using genomic and subgenomic dengue virus RNAs. We found that single mutations disrupting 5-3 complementarity greatly compromised viral RNA synthesis. Although in most of the cases incorporation of compensatory mutations re-established viral RNA replication, certain nucleotides were found to be involved in alternative secondary structures also important for viral replication. In addition, mutations within 5 or 3UAR in the context of an infectious dengue virus RNA resulted in spontaneous mutations that restored UAR base pairings. Together, we propose that specific UAR nucleotides as well as 5-3 UAR complementarity constitute cis-acting signals involved in amplification of the dengue virus genome.