Pseudouridylate synthase that catalyzes pseudouridylation of tRNAs and mRNAs. Acts on positions 27/28 in the anticodon stem and also positions 34 and 36 in the anticodon of an intron containing tRNA. Also catalyzes pseudouridylation of mRNAs: mediates pseudouridylation of mRNAs with the consensus sequence 5'-UGUAG-3'. Acts as a regulator of pre-mRNA splicing by mediating pseudouridylation of pre-mRNAs at locations associated with alternatively spliced regions. Pseudouridylation of pre-mRNAs near splice sites directly regulates mRNA splicing and mRNA 3'-end processing. Involved in regulation of nuclear receptor activity through pseudouridylation of SRA1 mRNA. a uridine in tRNA = a pseudouridine in tRNA uridine(38/39/40) in tRNA = pseudouridine(38/39/40) in tRNA a uridine in mRNA = a pseudouridine in mRNA Monomer (By similarity). Forms a complex with RARG and the SRA1 RNA in the nucleus (By similarity). Belongs to the tRNA pseudouridine synthase TruA family.