Using reporters with long unstructured 5’ UTRs, we examined which initiation factors are limiting for 40S scanning in yeast. Our results&literature led to the model that 40S scans 5’ UTRs for the start codon by one-dimensional diffusion rather than by helicase-driven translocation.
During eukaryotic translation initiation, the small (40S) ribosomal subunit is recruited to the 5ʹ cap and subsequently scans the 5ʹ untranslated region (5ʹ UTR) of mRNA in search of the start codon. ...
