Journal article
Role of Pseudouridine Formation by Deg1 for Functionality of Two Glutamine Isoacceptor tRNAs



Publication Details
Authors:
Klassen, R.; Schaffrath, R.
Publisher:
MDPI AG
Publication year:
2017
Journal:
BIOMOLECULES
Pages range:
8
Volume number:
7
Issue number:
1
Number of pages:
11
ISSN:
2218-273X

Abstract
Loss of Deg1/Pus3 and concomitant elimination of pseudouridine in tRNA at positions 38 and 39 (38/39) was shown to specifically impair the function of tRNA(UUG)(Gln) under 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 38/39 modification for tRNAs in yeast, we analyzed the in vivo function of non-sense suppressor tRNAs SUP4 and sup70-65 in the absence of the modifier. In the tRNA(GA)(Tyr) variant SUP4, UAA read-through is enabled due to an anticodon mutation (UA), whereas sup70-65 is a mutant form of tRNA(CUG)(Gln) (SUP70) that mediates UAG decoding due to a mutation of the anticodon-loop closing base pair (G31:C39 to A31:C39). While SUP4 function is unaltered in deg1/pus3 mutants, the ability of sup70-65 to mediate non-sense suppression and to complement a genomic deletion of the essential SUP70 gene is severely compromised. These results and the differential suppression of growth defects in deg1 mutants by multi-copy SUP70 or tQ(UUG) are consistent with the interpretation that 38 is most important for tRNA(UUG)(Gln) function under heat stress but becomes crucial for tRNA(CUG)(Gln) as well when the anticodon loop is destabilized by the sup70-65 mutation. Thus, 38/39 may protect the anticodon loop configuration from disturbances by loss of other modifications or base changes.


Keywords
5-methoxycarbonylmethyl-2-thiouridine, DEG1, non-sense suppression, PUS3, sup70-65, translation, tRNA modification


Authors/Editors

Last updated on 2019-25-07 at 19:12