frSi21 [col-62p::rde-1 3'UTR] II. frIs7 [nlp-29p::GFP + col-12p::DsRed] IV. frSi21 inserted into ttTi5605 site using CRISPR/Cas9 engineering. RDE-1 activity is rescued in adult epidermal tissues, making animals RNAi-deficient except for hypodermal (skin) tissues from the young adult stage. The frSi21 insertion can be detected using a primer within the col-62 promoter (jep2245: caaaaaggcgggatgagcag) in combination with downstream primer in rde-1 (jep2817 tcatactcgtagtattcccg), producing a 965 bp product if insertion is present. rde-1(ne300) can be genotyped by sequencing the PCR product from jep2299: gaacaacgacaatcgagcacca and jep3108: ATcttgtgaccgaactgtcc (jep3108 is not present in the frSi21 transgene). Reference: Watts JS, et al. G3 (Bethesda) 2020 Nov 5;10(11):4167-4176. PMID: 32943454