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RNA. 2018 Mar;24(3):410-422. doi: 10.1261/rna.064642.117. Epub 2017 Dec 19.

Widespread temperature sensitivity and tRNA decay due to mutations in a yeast tRNA.

Author information

1
Department of Biochemistry and Biophysics and Center for RNA Biology, University of Rochester School of Medicine, Rochester, New York 14642, USA.
2
Department of Genome Sciences, University of Washington, Seattle, Washington 98195, USA.
3
Department of Medicine, University of Washington, Seattle, Washington 98195, USA.
4
Howard Hughes Medical Institute, University of Washington, Seattle, Washington 98195, USA.
#
Contributed equally

Abstract

Microorganisms have universally adapted their RNAs and proteins to survive at a broad range of temperatures and growth conditions. However, for RNAs, there is little quantitative understanding of the effects of mutations on function at high temperatures. To understand how variant tRNA function is affected by temperature change, we used the tRNA nonsense suppressor SUP4oc of the yeast Saccharomyces cerevisiae to perform a high-throughput quantitative screen of tRNA function at two different growth temperatures. This screen yielded comparative values for 9243 single and double variants. Surprisingly, despite the ability of S. cerevisiae to grow at temperatures as low as 15°C and as high as 39°C, the vast majority of variants that could be scored lost half or more of their function when evaluated at 37°C relative to 28°C. Moreover, temperature sensitivity of a tRNA variant was highly associated with its susceptibility to the rapid tRNA decay (RTD) pathway, implying that RTD is responsible for most of the loss of function of variants at higher temperature. Furthermore, RTD may also operate in a met22Δ strain, which was previously thought to fully inhibit RTD. Consistent with RTD acting to degrade destabilized tRNAs, the stability of a tRNA molecule can be used to predict temperature sensitivity with high confidence. These findings offer a new perspective on the stability of tRNA molecules and their quality control at high temperature.

KEYWORDS:

RNA temperature sensitivity; SUP4; nonsense suppressor; tRNA; tRNA decay; thermal stability

PMID:
29259051
PMCID:
PMC5824359
DOI:
10.1261/rna.064642.117
[Indexed for MEDLINE]
Free PMC Article

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