Genetic identification of yeast 18S rRNA residues required for efficient recruitment of initiator tRNAMet and AUG selection
- 15 August 2008
- journal article
- Published by Cold Spring Harbor Laboratory in Genes & Development
- Vol. 22 (16), 2242-2255
- https://doi.org/10.1101/gad.1696608
Abstract
High-resolution structures of bacterial 70S ribosomes have provided atomic details about mRNA and tRNA binding to the decoding center during elongation, but such information is lacking for preinitiation complexes (PICs). We identified residues in yeast 18S rRNA critical in vivo for recruiting methionyl tRNAiMet to 40S subunits during initiation by isolating mutations that derepress GCN4 mRNA translation. Several such Gcd− mutations alter the A928:U1389 base pair in helix 28 (h28) and allow PICs to scan through the start codons of upstream ORFs that normally repress GCN4 translation. The A928U substitution also impairs TC binding to PICs in a reconstituted system in vitro. Mutation of the bulge G926 in h28 and certain other residues corresponding to direct contacts with the P-site codon or tRNA in bacterial 70S complexes confer Gcd− phenotypes that (like A928 substitutions) are suppressed by overexpressing tRNAiMet. Hence, the nonconserved 928:1389 base pair in h28, plus conserved 18S rRNA residues corresponding to P-site contacts in bacterial ribosomes, are critical for efficient Met-tRNAiMet binding and AUG selection in eukaryotes.Keywords
This publication has 33 references indexed in Scilit:
- Ribosomal position and contacts of mRNA in eukaryotic translation initiation complexesThe EMBO Journal, 2008
- Cryo-EM Visualization of a Viral Internal Ribosome Entry Site Bound to Human RibosomesCell, 2004
- Domain movements of elongation factor eEF2 and the eukaryotic 80S ribosome facilitate tRNA translocationThe EMBO Journal, 2004
- Communication Between Eukaryotic Translation Initiation Factors 1 and 1A on the Yeast Small Ribosomal SubunitJournal of Molecular Biology, 2003
- Position of eukaryotic initiation factor eIF1 on the 40S ribosomal subunit determined by directed hydroxyl radical probingGenes & Development, 2003
- Development and characterization of a reconstituted yeast translation initiation systemRNA, 2002
- Structure of the 80S Ribosome from Saccharomyces cerevisiae—tRNA-Ribosome and Subunit-Subunit InteractionsCell, 2001
- Hepatitis C Virus IRES RNA-Induced Changes in the Conformation of the 40 S Ribosomal SubunitScience, 2001
- [46] Antibiotic resistance mutations in ribosomal RNA genes of Escherichia coliMethods in enzymology, 1988
- A segment of GCN4 mRNA containing the upstream AUG codons confers translational control upon a heterologous yeast transcript.Proceedings of the National Academy of Sciences of the United States of America, 1987