Molecular Arms Race

Science's STKE  26 Apr 2005:
Vol. 2005, Issue 281, pp. tw158
DOI: 10.1126/stke.2812005tw158

Many invading viruses and transposons replicate and transpose through RNA intermediates. These intermediates can be detected by the host cell RNA interference machinery in plants and insects and used to generate small interfering RNAs (siRNAs), critical intermediates in silencing, which can then neutralize the invader. Lecellier et al. (see the news story by Couzin) now show that mammalian cells can also use the RNA silencing machinery to help neutralize an invading mammalian virus. Curiously, rather than siRNAs derived from the viral genome being the effector molecules that target the invader for silencing, a host microRNA tags the virus. The importance of the pathway in host defense is supported by the presence of a viral protein that can suppress the silencing effect.

C.-H. Lecellier, P. Dunoyer, K. Arar, J. Lehmann-Che, S. Eyquem, C. Himber, A. Saïb, O. Voinnet, A cellular microRNA mediates antiviral defense in human cells. Science 308, 557-560 (2005). [Abstract] [Full Text]

J. Couzin, Human RNA slows down a primate retrovirus. Science 308, 480-481 (2005). [Summary] [Full Text]