Leaky scanning is a mechanism used during the initiation phase of eukaryotic translation that enables regulation of gene expression.
During initiation, the small 40S ribosomal subunit (as a 43S PIC) "scans" or moves in a 5' --> 3' direction along the 5'UTR to locate a start codon to commence elongation.
Eukaryotic genes containing consistent G-C rich leader sequences are frequently observed performing this mechanism.
[4] Molecular biologists are narrowing the search of the ideal nucleotide environment for initiation of translation, and the mechanisms by which viruses replicate.
The AUG codon in mammals is optimally recognized by the context GCCRCCAUGG, also known as a “Kozak Consensus Sequence.”[5] Purine (R) and each of the nucleotides within this sequence are highly conserved and provide an important function in recognition and initiation of translation for many 40S ribosomal subunits.