Mechanism of mRNA Recognition by Eukaryotic Ribosomes During Initiation of Protein Synthesis

Abstract

There has been considerable speculation about what features in messenger RNA direct ribosomes to the site where peptide-bond formation is to begin. In prokaryotic systems, a substantial body of evidence supports Shine and Dalgarno’s proposal (1974) that base pairing occurs between the pyrimidine-rich 3’-end of 16S ribosomal RNA and a purine-rich sequence located approximately ten nucleotides to the left of the AUG initiator codon (Steitz and Jakes 1975; J.J. Dunn et al. 1978; Steitz 1979). This interaction plays a central role in recognition of initiation sites by bacterial ribosomes, although other features in prokaryotic mRNAs also influence the efficiency of ribosome binding (Lodish 1970; Taniguchi and Weissmann 1978; Borisova et al. 1979; Fill et al. 1980; Iserentant and Fiers 1980). The structural similarities between prokaryotic and eukaiyotic ribosomes (Boublik and Hellmann 1978; Gourse and Gerbi 1980; Tanaka et al. 1980) and the obvious parallels in the overall process of peptide-bond formation indicate a high degree of conservation during evolution of the protein synthesis machinery.