title: An evolutionary approach uncovers a diverse response of tRNA 2-thiolation to elevated temperatures in yeast.
abstract: Chemical modifications of transfer RNA (tRNA) molecules are evolutionarily well conserved and critical for translation and tRNA structure. Little is known how these nucleoside modifications respond to physiological stress. Using mass spectrometry and complementary methods, we defined tRNA modification levels in six yeast species in response to elevated temperatures. We show that 2-thiolation of uridine at position 34 (s(2)U34) is impaired at temperatures exceeding 30°C in the commonly used Saccharomyces cerevisiae laboratory strains S288C and W303, and in Saccharomyces bayanus. Upon stress relief, thiolation levels recover and we find no evidence that modified tRNA or s(2)U34 nucleosides are actively removed. Our results suggest that loss of 2-thiolation follows accumulation of newly synthesized tRNA that lack s(2)U34 modification due to temperature sensitivity of the URM1 pathway in S. cerevisiae and S. bayanus. Furthermore, our analysis of the tRNA modification pattern in selected yeast species revealed two alternative phenotypes. Most strains moderately increase their tRNA modification levels in response to heat, possibly constituting a common adaptation to high temperatures. However, an overall reduction of nucleoside modifications was observed exclusively in S288C. This surprising finding emphasizes the importance of studies that utilize the power of evolutionary biology, and highlights the need for future systematic studies on tRNA modifications in additional model organisms.
authors.affiliation: RNA Biology Laboratory, Max Planck Institute for Molecular Biomedicine, 48149 Münster, Germany.
authors.forename: Fiona
authors.initials: F
authors.lastname: Alings
authors.affiliation: RNA Biology Laboratory, Max Planck Institute for Molecular Biomedicine, 48149 Münster, Germany.
authors.forename: L Peter
authors.initials: LP
authors.lastname: Sarin
authors.affiliation: Institute of Plant Biology and Biotechnology, University of Münster, 48143 Münster, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Fufezan
authors.affiliation: Bioanalytical Mass Spectrometry Unit, Max Planck Institute for Molecular Biomedicine, 48149 Münster, Germany.
authors.forename: Hannes C A
authors.initials: HC
authors.lastname: Drexler
authors.affiliation: RNA Biology Laboratory, Max Planck Institute for Molecular Biomedicine, 48149 Münster, Germany Faculty of Medicine, University of Münster, 48149 Münster, Germany sebastian.leidel@mpi-muenster.mpg.de.
authors.forename: Sebastian A
authors.initials: SA
authors.lastname: Leidel
mesh_terms: D019143:Evolution, Molecular; D010802:Phylogeny; D012323:RNA Processing, Post-Transcriptional; D012331:RNA, Fungal / Q000096:biosynthesis / Q000235:genetics*; D012343:RNA, Transfer / Q000096:biosynthesis / Q000235:genetics*; D012441:Saccharomyces cerevisiae / Q000235:genetics* / Q000254:growth & development; D029701:Saccharomyces cerevisiae Proteins; D013438:Sulfhydryl Compounds / Q000378:metabolism; D013696:Temperature; D014158:Transcription, Genetic
chemical_list: D012331:RNA, Fungal; D029701:Saccharomyces cerevisiae Proteins; D013438:Sulfhydryl Compounds; C406282:URM1 protein, S cerevisiae; D012343:RNA, Transfer
keywords: URM1; evolution; tRNA modification; temperature stress; yeast