Pseudouridylate Synthase 1 (PUS1)

PUS1 converts uridine into pseudouridine after the nucleotide has been incorporated into RNA. Pseudouridine may have a functional role in tRNAs and may assist in the peptidyl transfer reaction of rRNAsPUS1-1 encodes a protein with an N-terminal mitochondrial leader peptide. Western blot analysis detected full-length PUS1-1 at an apparent molecular mass of 47 kD, and the mature protein, lacking the mitochondrial localization signal, was about 37 kD. The PUS1-2 and PUS1-3 transcripts differ in the 5-prime untranslated region but encode the same protein that begins with an internal methionine (met29) relative to PUS1-1. Immunofluorescence localized PUS1-1 to mitochondria and PUS1-2 and PUS1-3 to nuclei.