Abstract

Double-stranded RNA (dsRNA)-specific endonucleases belonging to RNase III classes 3 and 2 process dsRNA precursors to small interfering RNA (siRNA) or microRNA, respectively, thereby initiating and amplifying RNA silencing-based antiviral defense and gene regulation in eukaryotic cells. However, we now provide evidence that a class I RNase III is involved in suppression of RNA silencing. The single-stranded RNA genome of sweet potato chlorotic stunt virus (SPCSV) encodes an RNase III (RNase3) homologous to putative class I RNase Ills of unknown function in rice and Arabidopsis. We show that RNase3 has dsRNA-specific endonuclease activity that enhances the RNA-silencing suppression activity of another protein (p22) encoded by SPCSV. RNase3 and p22 coexpression reduced siRNA accumulation more efficiently than p22 alone in Nicotiana benthamiana leaves expressing a strong silencing inducer (i.e., dsRNA). RNase3 did not cause intracellular silencing suppression or reduce accumulation of siRNA in the absence of p22 or enhance silencing suppression activity of a protein encoded by a heterologous virus. No other known RNA virus encodes an RNase III or uses two independent proteins cooperatively for RNA silencing suppression

Published in

Journal of Virology
2005, Volume: 79, number: 11, pages: 7227-7238
Publisher: AMER SOC MICROBIOLOGY

SLU Authors

• Savenkov, Eugene

  • Department of Plant Biology, Swedish University of Agricultural Sciences
    

• Valkonen, Jari

  • Department of Plant Biology, Swedish University of Agricultural Sciences
    

UKÄ Subject classification

Agricultural Science


Publication identifier

DOI: https://doi.org/10.1128/JVI.79.11.7227-7238.2005

Permanent link to this page (URI)

https://res.slu.se/id/publ/8416