Figure 5.

Interaction of silencing-suppressor proteins with small RNAs in vitro and in virus-infected leaves. AS3 is not able to interfere with viral siRNA 3′ protection, while the wt HC-Pro partially inhibits the 3′ protection of cytoplasmic viral siRNAs. RNA samples were collected from inoculated leaves, which were infiltrated with the suppressors 6 h post-inoculation. The 20 µg of total RNA were used for each sample and 10 pmol of synthetic GFP RNA oligo was used as an internal control for β-elimination (A). RNA-binding activity of wt and mutant silencing suppressor proteins (B). The 21-nt siRNA duplexes were incubated with a dilution series of purified p19 and p19-W39G (upper panels) or A3 and HC-Pro infiltrated plant extracts and analysed on 5% native 0.5 × TBE gel.