Conserved residues in yeast initiator tRNA calibrate initiation accuracy by regulating preinitiation complex stability at the start codon.

ABSTRACT: Eukaryotic initiator tRNA (tRNAi) contains several highly conserved unique sequence features, but their importance in accurate start codon selection was unknown. Here we show that conserved bases throughout tRNAi, from the anticodon stem to acceptor stem, play key roles in ensuring the fidelity of start codon recognition in yeast cells. Substituting the conserved G31:C39 base pair in the anticodon stem with different pairs reduces accuracy (the Sui(-) [suppressor of initiation codon] phenotype), whereas eliminating base pairing increases accuracy (the Ssu(-) [suppressor of Sui(-)] phenotype). The latter defect is fully suppressed by a Sui(-) substitution of T-loop residue A54. These genetic data are paralleled by opposing effects of Sui(-) and Ssu(-) substitutions on the stability of methi

SUBMITTER: Dong J 

PROVIDER: S-EPMC3950347 | biostudies-literature | 2014 Mar

REPOSITORIES: biostudies-literature