Conservation and Variability of the AUG Initiation Codon Context in Eukaryotes.
Trends Biochem Sci 2019;
44:1009-1021. [PMID:
31353284 DOI:
10.1016/j.tibs.2019.07.001]
[Citation(s) in RCA: 49] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2018] [Revised: 06/22/2019] [Accepted: 07/02/2019] [Indexed: 01/30/2023]
Abstract
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.
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