Poster abstracts

Poster number 158 submitted by Thomas Vornheder

The use of fission yeast to study the roles of eukaryotic tRNA modifications

Thomas Vornheder (Chemistry; Northern Kentucky University), Maggie Thomas (Chemistry; Northern Kentucky University), Jennifer H. Brooks (Chemistry; Northern Kentucky University), Shelby Russell (Chemistry; Northern Kentucky University), Kathleen McElheney (Chemistry; Northern Kentucky University), Michael P. Guy (Chemistry; Northern Kentucky University)

Abstract:
tRNA must be chemically modified by cellular enzymes to function properly, and defects in these modifications are often associated with human disease. For example, mutations in human FTSJ1, an enzyme required for 2’-O-methylation of tRNA residues 32 (Nm32) and 34 (Nm34) cause non-syndromic X-linked intellectual disability, and upregulation of human DUS2, an enzyme required for dihydrouridine modification of tRNA residue 20 (D20) is linked to non-small cell lung cancer. Despite these links to disease, the precise translational roles of many tRNA modifications are not clear. We are using the fission yeast Schizosaccharomyces pombe as a model to study the cellular roles of several important eukaryotic tRNA modifications such as Nm34 and D20. We previously reported that trm734+ deletion mutants (which lack Nm34) grow slowly in fission yeast due to a defect in tRNAPhe. We report here that trm734+ deletion mutants are also sensitive to cycloheximide, indicating that Nm34 may be important for translational elongation. Furthermore, we have isolated suppressors of the trm734+ deletion strain that overcome the slow growth of mutants and alleviate cycloheximide sensitivity. We are currently working to identify the suppressing mutation(s) in these strains, and to determine which hypomodified tRNA(s) is affected by cycloheximide. In addition, to further define the roles of tRNA modifications in fission yeast, we are setting up a reporter system to quantitatively study the effects of modifications on a model suppressor tRNA.

Keywords: tRNA, S pombe, modifications