Suppression of endogenous gene silencing by bidirectional cytoplasmic RNA decay in Arabidopsis

Protecting against runaway defense systems RNA interference defends cells against invading genetic elements, such as viruses or transgenes. But while the invasive RNAs are under attack, what protects the normal endogenous RNAs? Zhang et al. identified, in the small plant Arabidopsis , a surveillance system to do just that: Preserve the normal transcriptome and keep the attack focused on invasive transcripts. Science , this issue p. 120