title: Role of Pseudouridine Formation by Deg1 for Functionality of Two Glutamine Isoacceptor tRNAs.
abstract: Loss of Deg1/Pus3 and concomitant elimination of pseudouridine in tRNA at positions 38 and 39 (ψ38/39) was shown to specifically impair the function of tRNAGlnUUGunder conditions of temperature-induced down-regulation of wobble uridine thiolation in budding yeast and is linked to intellectual disability in humans. To further characterize the differential importance of the frequent ψ38/39 modification for tRNAs in yeast, we analyzed the in vivo function of non-sense suppressor tRNAsSUP4andsup70-65in the absence of the modifier. In the tRNATyrGψAvariantSUP4, UAA read-through is enabled due to an anticodon mutation (UψA), whereassup70-65is a mutant form of tRNAGlnCUG(SUP70) that mediates UAG decoding due to a mutation of the anticodon-loop closing base pair (G31:C39 to A31:C39). WhileSUP4function is unaltered indeg1/pus3mutants, the ability ofsup70-65to mediate non-sense suppression and to complement a genomic deletion of the essentialSUP70gene is severely compromised. These results and the differential suppression of growth defects indeg1mutants by multi-copySUP70ortQ(UUG)are consistent with the interpretation that ψ38 is most important for tRNAGlnUUGfunction under heat stress but becomes crucial for tRNAGlnCUGas well when the anticodon loop is destabilized by thesup70-65mutation. Thus, ψ38/39 may protect the anticodon loop configuration from disturbances by loss of other modifications or base changes.
authors.affiliation: Institut für Biologie, Fachgebiet Mikrobiologie, Universität Kassel, Heinrich-Plett-Str. 40, D-34132 Kassel, Germany. roland.klassen@uni-kassel.de.
authors.forename: Roland
authors.initials: R
authors.lastname: Klassen
authors.affiliation: Institut für Biologie, Fachgebiet Mikrobiologie, Universität Kassel, Heinrich-Plett-Str. 40, D-34132 Kassel, Germany. schaffrath@uni-kassel.de.
authors.forename: Raffael
authors.initials: R
authors.lastname: Schaffrath
mesh_terms: D019751:Intramolecular Transferases / Q000235:genetics / Q000378:metabolism*; D009154:Mutation; D014176:Protein Biosynthesis; D011560:Pseudouridine / Q000378:metabolism*; D012331:RNA, Fungal / Q000235:genetics; D012351:RNA, Transfer, Gln / Q000235:genetics*; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism*
chemical_list: D012331:RNA, Fungal; D012351:RNA, Transfer, Gln; D029701:Saccharomyces cerevisiae Proteins; D011560:Pseudouridine; D019751:Intramolecular Transferases; C068903:DEG1 protein, S cerevisiae
keywords: 5-methoxycarbonylmethyl-2-thiouridine; PUS3/DEG1; non-sense suppression; sup70-65; tRNA modification; translation