A link between RNA interference and nonsense-mediated decay in Caenorhabditis elegans

Double-stranded RNA (dsRNA) inhibits expression of homologous genes by a pr ocess' involving messenger RNA degradation. To gain insight into the mechan ism of degradation, we examined how RNA interference is affected by mutatio ns in the smg genes, which are required for nonsense-mediated decay. For th ree of six smg genes tested, mutations resulted in animals that were initia lly silenced by dsRNA but then recovered; wild-type animals remained silenc ed. The Levels of target messenger RNAs were restored during recovery, and RNA editing and degradation of the dsRNA were identical to those of the wil d type. We suggest that persistence of RNA interference relies on a subset of smg genes.