Non-structural protein 1 from avian influenza virus H9N2 is an efficient RNA silencing suppressor with characteristics that differ from those of Tomato bushy stunt virus p19

In this study, we showed that the NS1 protein from avian influenza virus (AIV) H9N2 suppressed systemic RNA silencing induced by sense RNA or dsRNA. It resulted in more severePotato virus X symptom, but could not reverse established systemic green fluorescent protein silencing inNicotiana benthamiana. In addition, its systemic silencing suppression activity was much weaker than that of p19. The local silencing suppression activity of AIV H9N2 NS1 was most powerful at 7  dpi and was even stronger than that of p19. And the inhibition ability to RNA silencing of NS1 is stronger than that of p19 in human cells. Collectively, these results indicate that AIV H9N2 NS1 is an effective RNA silencing suppressor that likely targets downstream step(s) of dsRNA formation at a n early stage in RNA silencing. Although NS1 and p19 both bind siRNA, their suppression mechanisms seem to differ because of differences in their suppression activities at various times post-infiltration and because p19 can reverse established systemic RNA silencing, but NS1 cannot.
Source: Virus Genes - Category: Genetics & Stem Cells Source Type: research