Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
6143067 | Virus Research | 2012 | 10 Pages |
Genome cyclization through conserved RNA sequences located in the 5â² and 3â² terminal regions of flavivirus genomic RNA is essential for virus replication. Although the role of various cis-acting RNA elements in panhandle formation is well characterized, almost nothing is known about the potential contribution of protein cofactors to viral RNA cyclization. Proteins with nucleic acid chaperone activities are encoded by many viruses (e.g., retroviruses, coronaviruses) to facilitate RNA structural rearrangements and RNA-RNA interactions during the viral replicative cycle. Since the core protein of flaviviruses is also endowed with potent RNA chaperone activities, we decided to examine the effect of West Nile virus (WNV) core on 5â²-3â² genomic RNA annealing in vitro. Core protein binding resulted in a dramatic, dose-dependent increase in 5â²-3â² complex formation. Mutations introduced in either the UAR (upstream AUG region) or CS (conserved sequence) elements of the viral RNA diminished core protein-dependent annealing, while compensatory mutations restored the 5â²-3â² RNA interaction. The activity responsible for stimulating RNA annealing was mapped to the C-terminal RNA-binding region of WNV core protein. These results indicate that core protein - besides its function in viral particle formation - might be involved in the regulation of flavivirus genomic RNA cyclization, and thus virus replication.
⺠WNV is a member of the flavivirus family. ⺠Alexander the Great died of WNV infection in Babylon, around 325 years BC. ⺠WNV core protein mediates genomic RNA circularization by virtue of its RNA chaperoning activity.