Open AccessEukaryotic Wobble Uridine Modifications Promote a Functionally Redundant Decoding System
Author(s) -
Marcus Johansson,
Anders Esberg,
Bo Huang,
Glenn R. Björk,
Andeŕs S. Byström
Publication year - 2008
Publication title -
molecular and cellular biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.14
H-Index - 327
eISSN - 1067-8824
pISSN - 0270-7306
DOI - 10.1128/mcb.01542-07
Subject(s) - wobble base pair , biology , uridine , transfer rna , translation (biology) , nucleoside , saccharomyces cerevisiae , biochemistry , in vivo , genetics , computational biology , messenger rna , rna , yeast , gene
The translational decoding properties of tRNAs are modulated by naturally occurring modifications of their nucleosides. Uridines located at the wobble position (nucleoside 34 [U34 ]) in eukaryotic cytoplasmic tRNAs often harbor a 5-methoxycarbonylmethyl (mcm5 ) or a 5-carbamoylmethyl (ncm5 ) side chain and sometimes an additional 2-thio (s2 ) or 2′-O -methyl group. Although a variety of models explaining the role of these modifications have been put forth, their in vivo functions have not been defined. In this study, we utilized recently characterized modification-deficientSaccharomyces cerevisiae cells to test the wobble rules in vivo. We show that mcm5 and ncm5 side chains promote decoding of G-ending codons and that concurrent mcm5 and s2 groups improve reading of both A- and G-ending codons. Moreover, the observation that the mcm5 U34 - and some ncm5 U34 -containing tRNAs efficiently read G-ending codons challenges the notion that eukaryotes do not use U-G wobbling.