Fig. 4.

Efficient import of dsRNA requires sid-3. (A) Response to different concentrations of dsRNA injected into the germline. Adult animals of wild-type, rde-1(−), and two sid-3(−) genotypes [sid-3(W310*)–sid-3(*) and the tm342 deletion–sid-3(∆)] were injected with a similar volume of the indicated pal-1 dsRNA concentrations. pal-1-RNAi is embryonic lethal. The proportion of dead embryos laid by each injected animal (circle) and the average pooled proportion of dead embryos for each concentration and genotype (X) is plotted. (B) Response to limiting amounts of dsRNA (10 ng/μL) injected into the germ line of wild-type and sid-3(W310*) animals. Red bars and circles indicate average and individual proportions of dead embryos laid, respectively. P value is based on Mann–Whitney U test. (C) Schematic of experiment to test the role of SID-3 in exporting and importing tissues. (D) SID-3 is not required in the exporting tissue but is required in the importing tissue for silencing because of mobile RNA. sid-3(−) animals that express GFP in the pharynx and in bwm cells but express gfp-dsRNA only in the pharynx were transformed with constructs that express sid-3(+) under the control of its own (sid-3), bwm-specific (bwm), or pharynx-specific (phar) promoter and the percentage of transgenic animals that show gfp silencing in bwm cells was determined. Error bars indicate 95% confidence intervals. n = 100 L4 animals; *P < 0.05.