Affiliation:
1. Department of Cell Biology and Physiology, Washington University School of Medicine, St. Louis, Missouri
2. Department of Biochemistry and Molecular Biology, University of Louisville School of Medicine, Louisville, Kentucky 40292
Abstract
ABSTRACT
The anticodon stem-loop of tRNAs requires extensive posttranscriptional modifications in order to maintain structure and stabilize the codon-anticodon interaction. These modifications also play a role in accommodating wobble, allowing a limited pool of tRNAs to recognize degenerate codons. Of particular interest is the formation of a threonylcarbamoyl group on adenosine 37 (t
6
A
37
) of tRNAs that recognize ANN codons. Located adjacent and 3′ to the anticodon, t
6
A
37
is a conserved modification that is critical for reading frame maintenance. Recently, the highly conserved YrdC/Sua5 family of proteins was shown to be required for the formation of t
6
A
37
. Sua5 was originally identified in a screen by virtue of its ability to affect expression from an aberrant upstream AUG codon in the
cyc1
transcript. Together, these findings implicate Sua5 in protein translation at the level of codon recognition. Here, we show that Sua5 is critical for normal translation. The loss of
SUA5
causes increased leaky scanning through AUG codons, +1 frameshifting, and nonsense suppression. In addition, the loss of
SUA5
amplifies the 20S RNA virus found in
Saccharomyces cerevisiae
, possibly through an internal ribosome entry site-mediated mechanism. This study reveals a critical role for Sua5 and the t
6
A
37
modification in translational fidelity.
Publisher
American Society for Microbiology
Subject
Cell Biology,Molecular Biology
Cited by
62 articles.
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