PUS10-induced tRNA fragmentation impacts retrotransposon-driven inflammation

Pseudouridine synthases (PUSs) catalyze the isomerization of uridine (U)-to-pseudouridine (Ψ) and have emerging roles in development and disease. How PUSs adapt gene expression under stress remains mostly unexplored. We identify an unconventional role for the Ψ “writer” PUS10 impacting intracellular innate immunity. Using Pus10 knock-out mice, we uncover cell-intrinsic upregulation of interferon (IFN) signalling, conferring resistance to inflammation in vivo. Pus10 loss alters tRNA-derived small RNAs (tdRs) abundance, perturbing translation and endogenous retroelements expression. We found one of the differentially expressed tDRs is derived from tRNA glycine (tDR Gly). To delinate the tDR Gly interactome, we employed an optimized pull-down strategy using PUS10 KO cells followed by data-independent acquisition-based quantitative mass spectrometry analysis.