Gene

Context (archaeology)

Sequence motif

Biology

Messenger RNA

Conserved sequence

Acoustics

Base sequence

Computational biology

Evolutionary biology

Translation (biology)

Paleontology

Start codon

Genetics

Physics

Nucleotide

Motif (music)

Consensus sequence

In silico

Peptide sequence

Eukaryotic translation

Trends in Biochemical Sciences

Selection of the translation initiation site (TIS) is a crucial step during translation. In the 1980s Marylin Kozak performed key studies on vertebrate mRNAs to characterize the optimal TIS consensus sequence, the Kozak motif. Within this motif, conservation of nucleotides in crucial positions, namely a purine at -3 and a G at +4 (where the A of the AUG is numbered +1), is essential for TIS recognition. Ever since its characterization the Kozak motif has been regarded as the optimal sequence to initiate translation in all eukaryotes. We revisit here published in silico data on TIS consensus sequences, as well as experimental studies from diverse eukaryotic lineages, and propose that, while the -3A/G position is universally conserved, the remaining variability of the consensus sequences enables their classification as optimal, strong, and moderate TIS sequences.

Conservation and Variability of the AUG Initiation Codon Context in Eukaryotes