Enhanced neuronal RNAi in C. elegans using SID-1

Expression of the transporter SID-1 in Caenorhabditis elegans neurons renders the cells sensitive to systemic RNAi and permits previously unidentified neuronal phenotypes to be uncovered. This expression also reduces RNAi in nonneuronal cell types, allowing examination of neuronal functions of lethal genes. We expressed SID-1, a transmembrane protein from Caenorhabditis elegans that is required for systemic RNA interference (RNAi), in C. elegans neurons. This expression increased the response of neurons to double-stranded (ds)RNA delivered by feeding. Mutations in the lin-15b and lin-35 genes enhanced this effect. Worms expressing neuronal SID-1 showed RNAi phenotypes when fed with bacteria expressing dsRNA for known neuronal genes and for uncharacterized genes with no previously known neuronal phenotypes. Neuronal expression of sid-1 decreased nonneuronal RNAi, suggesting that neurons expressing transgenic sid-1(+) served as a sink for dsRNA. This effect, or a sid-1(–) background, can be used to uncover neuronal defects for lethal genes. Expression of sid-1(+) from cell-specific promoters in sid-1 mutants results in cell-specific feeding RNAi. We used these strains to identify a role for integrin signaling genes in mechanosensation.