Premium
Selective stimulation of translation of leaderless mRNA by initiation factor 2: evolutionary implications for translation
Author(s) -
Grill Sonja,
Gualerzi Claudio O.,
Londei Paola,
Bläsi Udo
Publication year - 2000
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1093/emboj/19.15.4101
Subject(s) - biology , translation (biology) , messenger rna , eukaryotic translation , stimulation , genetics , protein biosynthesis , eif4e , microbiology and biotechnology , computational biology , neuroscience , gene
Translation initiation in bacteria involves a stochastic binding mechanism in which the 30S ribosomal subunit first binds either to mRNA or to initiator tRNA, fMet‐tRNA f Met . Leaderless λ c I mRNA did not form a binary complex with 30S ribosomes, which argues against the view that ribosomal recruitment signals other than a 5′‐terminal start codon are essential for translation initiation of these mRNAs. We show that, in Escherichia coli , translation initiation factor 2 (IF2) selectively stimulates translation of λ c I mRNA in vivo and in vitro . These experiments suggest that the start codon of leaderless mRNAs is recognized by a 30S–fMet‐tRNA f Met –IF2 complex, an intermediate equivalent to that obligatorily formed during translation initiation in eukaryotes. We further show that leaderless λ c I mRNA is faithfully translated in vitro in both archaebacterial and eukaryotic translation systems. This suggests that translation of leaderless mRNAs reflects a fundamental capability of the translational apparatus of all three domains of life and lends support to the hypothesis that the translation initiation pathway is universally conserved.