RNA Interference in Caenorhabditis elegans

The introduction of double-stranded RNA (dsRNA) into Caenorhabditis elegans hermaphrodites results in the rapid and sequence-specific degradation of endogenous mRNAs (1 ,2 ). This RNA-mediated interference, or RNAi, effectively shuts down expression of the target gene and can phenocopy loss-of-function mutations. RNAi is also remarkably potent, requiring only substoichiometric amounts of dsRNA to elicit a response (1 ). Another notable aspect of RNAi in C. elegans is that it is systemic in that the silencing can spread between tissues throughout the adult as well as its progeny (1 ,3 ,4 ). Many neurons, however, are refractory to the spreading effect in wild-type backgrounds (5 ).