RNAi and double-strand RNA（RNAi技术和双链RNA）

Double-strand RNA (dsRNA) is a signal for gene-specific silencing of expression in a number of organisms. This phenomenon was demonstrated recently in Caenorhabditis elegans when dsRNA was injected into the worm and the corresponding gene products disappeared from both the somatic cells of the organism as well as in its F1 progeny (Fire et al. 1998). This RNA interference, RNAi, has been generalized to many genes in C. elegans (Montgomery and Fire 1998; Shi and Mello 1998; Tabara et al. 1998; Timmons and Fire 1998). ds-RNA can also suppress expression of specific genes in plants, a component of the phenomenon called cosuppression (Vionnet et al. 1998; Waterhouse et al. 1998). Two recent reports document dsRNA-mediated interference with expression of specific genes in other organisms. Double-strand RNA produced gene-specific phenotypes in Trypanosoma brucei (Ngo et al. 1998) and, very recently, dsRNA-mediated interference was demonstrated in Drosophila (Kennerdell and Carthew 1998). Thus, the RNAi phenomenon is likely to be a general mechanism for gene regulation and may be critical for many developmental and antiviral processes.