The Saccharomyces cerevisiae U2 snRNA:pseudouridine-synthase Pus7p is a novel multisite–multisubstrate RNA:Ψ-synthase also acting on tRNAs

Disruption of the PUS7 gene does not alter formation of Ψ residue in U1 (A) and U5 snRNAs (B). Total RNA was extracted from the WT and mat-a ΔPUS7 S. cerevisiae BY4742 strains and modified by CMCT, for 1, 10, and 20 min with (+) or without (−) subsequent alkaline treatment (OH⁻). A control experiment was performed in the absence of CMCT treatment. Lanes U, G, C, and A correspond to the sequencing ladders obtained with the same oligonucleotide. The reverse transcription stops, corresponding to residues Ψ5 and Ψ6 (A) and to Ψ99 (B) are indicated by arrows.