Poly(UG)-tailed RNAs in Pristionchus pacificus
In the nematode Caenorhabditis elegans, the terminal transferase RDE-3 adds a poly(UG)-tail to the free 3' end of RNA molecules generated by the action of primary siRNAs or piRNAs. The tailed RNA serves as a template for RNA-dependent RNA polymerases (RdRp) to generate secondary siRNAs, thereby reinforcing the RNAi effect. In this iterative process, progressively shorter tailed RNAs are formed. In C. elegans, injection of poly(UG)-tailed single-stranded RNA (ssRNA) leads to RNAi-mediated gene silencing, thereby bypassing the need for the processing of double-stranded RNA into siRNAs. We wondered if poly(UG)-tailed ssRNAs could also be used for experimental gene knockdown in nematodes where long dsRNA-mediated RNAi does not work reliably, such as the satellite model organism Pristionchus pacificus or parasitic nematodes of the genus Strongyloides.