A connection between the ribosome and two < i > S < /i > . < i > pombe < /i > tRNA modification mutants subject to rapid tRNA decay

by Thareendra De Zoysa, Alayna C. Hauke, Nivedita R. Iyer, Erin Marcus, Sarah M. Ostrowski, Franziska Stegemann, Dmitri N. Ermolenko, Justin C. Fay, Eric M. Phizicky

tRNA modifications are crucial in all organisms to ensure tRNA folding and stability, and accurate translation. In both the yeastSaccharomyces cerevisiae and the evolutionarily distant yeastSchizosaccharomyces pombe, mutants lacking certain tRNA body modifications (outside the anticodon loop) are temperature sensitive due to rapid tRNA decay (RTD) of a subset of hypomodified tRNAs. Here we show that for each of twoS.pombe mutants subject to RTD, mutations in ribosomal protein genes suppress the temperature sensitivity without altering tRNA levels. Prior work showed thatS.pombe trm8 Δ mutants, lacking 7-methylguanosine, were temperature sensitive due to RTD, and that one class of suppressors had mutations in the general amino acid control (GAAC) pathway, which was activated concomitant with RTD, resulting in further tRNA loss. We now find that another class ofS.pombe trm8 Δ suppressors have mutations inrpl genes, encoding 60S subunit proteins, and that suppression occurs with minimal restoration of tRNA levels and reduced GAAC activation. Furthermore,trm8 Δ suppression extends to other mutations in the large or small ribosomal subunit. We also find thatS.pombe tan1 Δ mutants, lacking 4-acetylcytidine, are temperature sensitive due to RTD, that one class of suppressors haverpl mutations, associated with minima...

Source: PLoS Genetics - January 31, 2024 Category: Genetics & Stem Cells Authors: Thareendra De Zoysa Source Type: research