Eukaryotic ribosomes can recognize preproinsulin initiation codons irrespective of their position relative to the 5′ end of mRNA

The functional assay of a eukaryotic mRNA, into which additional AUG codons have been introduced by in vitro mutagenesis, shows that a translational initiation site need not necessarily be the nearest AUG codon to the 5′ end of a mRNA. Hence, the sequence surrounding the AUG, and not simply its position relative to the 5′ end of mRNA, appears to be important in determining initiation efficiency.