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Modulation of ribosomal recruitment to 5′‐terminal start codons by translation initiation factors IF2 and IF3
Author(s) -
Grill Sonja,
Moll Isabella,
Hasenöhrl David,
Gualerzi Claudio O.,
Bläsi Udo
Publication year - 2001
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(01)02378-x
Subject(s) - eukaryotic initiation factor , initiation factor , eif2 , ribosome , eukaryotic translation , shine dalgarno sequence , start codon , biology , ribosomal rna , messenger rna , microbiology and biotechnology , translation (biology) , translational frameshift , translational regulation , internal ribosome entry site , 30s , genetics , rna , gene
Sequence determinants and structural features of the RNA govern mRNA–ribosome interaction in bacteria. However, ribosomal recruitment to leaderless mRNAs, which start directly with the AUG start codon and do not bear a Shine–Dalgarno sequence like canonical mRNAs, does not appear to rely on 16S rRNA–mRNA interactions. Here, we have studied the effects of translation initiation factors IF2 and IF3 on 30S initiation at a 5′‐terminal AUG and at a competing downstream canonical ribosome binding site. We show that IF2 affects the forward kinetics of 30S initiation complex formation at the 5′‐terminal AUG as well as the stability of these complexes. Moreover, the IF2:IF3 molar ratio was found to play a decisive role in translation initiation of a leaderless mRNA both in vitro and in vivo indicating that the translational efficiency of an mRNA is not only intrinsically determined but can be altered depending on the availability of components of the translational machinery.