Editors' ChoiceVirology

Orchestrating a viral takeover

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Sci. Signal.  13 Oct 2015:
Vol. 8, Issue 398, pp. ec294
DOI: 10.1126/scisignal.aad6016

For some pathogenic viruses, outbreaks occur when a new viral strain emerges and displaces the endemic strain. How such a takeover occurs at a molecular level, however, remains an open question. Manokaran et al. examined one example, the emergence of a new clade of dengue virus (DENV) that caused an outbreak in Puerto Rico in 1994. The epidemic strain produced elevated amounts of subgenomic flavivirus RNA (sfRNA), a viral noncoding RNA, relative to amounts of genomic viral RNA. sfRNA bound to and inhibited TRIM25, a protein important for activating the host's antiviral response, and so by reducing host immunity was able to increase its own fitness.

G. Manokaran, E. Finol, C. Wang, J. Gunaratne, J. Bahl, E. Z. Ong, H. C. Tan, O. M. Sessions, A. M. Ward, D. J. Gubler, E. Harris, M. A. Garcia-Blanco, E. E. Ooi, Dengue subgenomic RNA binds TRIM25 to inhibit interferon expression for epidemiological fitness. Science 350, 217–221 (2015). [Abstract] [Full Text]