Viral suppression of RNA silencing: 2b wins the Golden Fleece by defeating Argonaute.
In plants, virus-derived double-stranded RNA is processed into small interfering (si)RNAs by RNAse III-type enzymes. siRNAs are believed to guide an RNA-induced silencing complex (RISC) to promote sequence-specific degradation (or 'slicing') of homologous viral transcripts. This process, called RNA silencing, likely involves Argonaute (AGO) proteins that are known components of plant and animal RISCs. Plant viruses commonly counteract the silencing immune response by producing suppressor proteins, but the molecular basis of their action has remained largely unclear. A recent study by Zhang and colleagues now shows that the 2b suppressor of Cucumber mosaic virus directly interacts with Arabidopsis AGO1 and inhibits its slicing activity, suggesting that AGO1 might be a component of the elusive plant antiviral RISC.
Ruiz-Ferrer
Virginia
V
Institut de Biologie Moléculaire des Plantes CNRS UPR235, Université Louis Pasteur, Strasbourg, France.
Voinnet
Olivier
O
D000818:Animals; D029681:Arabidopsis Proteins / Q000037:antagonists & inhibitors* / Q000378:metabolism; D060565:Argonaute Proteins; D010942:Plant Viruses / Q000235:genetics / Q000378:metabolism*; D011485:Protein Binding; D034622:RNA Interference; D034743:RNA-Induced Silencing Complex / Q000037:antagonists & inhibitors* / Q000378:metabolism; D014764:Viral Proteins / Q000235:genetics / Q000378:metabolism*
C117457:AGO1 protein, Arabidopsis; D029681:Arabidopsis Proteins; D060565:Argonaute Proteins; D034743:RNA-Induced Silencing Complex; D014764:Viral Proteins