A role for the RNase III enzyme DCR-1 in RNA interference and germ line development in Caenorhabditis elegans

An early event in RNA interference (RNAi) is the cleavage of the initiating double-stranded RNA (dsRNA) to short pieces, 21 to 23 nucleotides in lengt h. Here we describe a null mutation in dicer-1 (dcr-1), a gene proposed to encode the enzyme that generates these short RNAs. We find that dcr-1(-/-) animals have defects in RNAi under some, but not all, conditions. Mutant an imals have germ line defects that lead to sterility, suggesting that cleava ge of dsRNA to short pieces is a requisite event in normal development.