Abstract: Endogenous siRNAs (endo-siRNAs) are key regulators of RNA silencing in plants and worms; however, the biogenesis and function of endogenous siRNAs in mammals remain largely unknown. We previously demonstrated that human telomerase reverse transcriptase produces a self-targeting endogenous siRNA from non-coding RMRP RNA via RNA-dependent RNA polymerase (RdRP) activity. Here, we investigated whether the endo-siRNA derived from RMRP targets other genes in addition to RMRP. Four algorithms for microRNA target prediction were used to identify possible targets of the endo-siRNA, and the phytanoyl-CoA hydroxylase-interacting protein-like gene (PHYHIPL) was identified as the most promising candidate. The 3' UTR of PHYHIPL was found to contain three possible target sites with perfect seed pairing; deletion of each of these sites resulted in recovery of upstream luciferase expression. In addition, sequence-specific inhibition of the RMRP-derived endo-siRNA increased expression of PHYHIPL mRNA. The results described here suggest that the endo-siRNA uses silencing mechanisms that are similar to those used by microRNAs for gene silencing. To our knowledge, this study is the first confirmation of the off-target effect of human endogenous siRNA produced by RdRP activity.
Keywords: endogenous siRNA; hTERT; off-targeting; RNA-dependent RNA polymerase
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Maida, Y.; Kyo, S.; Lassmann, T.; Hayashizaki, Y.; Masutomi, K. Off-Target Effect of Endogenous siRNA Derived from RMRP in Human Cells. Int. J. Mol. Sci. 2013, 14, 9305-9318.
Maida Y, Kyo S, Lassmann T, Hayashizaki Y, Masutomi K. Off-Target Effect of Endogenous siRNA Derived from RMRP in Human Cells. International Journal of Molecular Sciences. 2013; 14(5):9305-9318.
Maida, Yoshiko; Kyo, Satoru; Lassmann, Timo; Hayashizaki, Yoshihide; Masutomi, Kenkichi. 2013. "Off-Target Effect of Endogenous siRNA Derived from RMRP in Human Cells." Int. J. Mol. Sci. 14, no. 5: 9305-9318.