Adherence to the first-AUG rule when a second AUG codon follows closely upon the first - PubMed (original) (raw)

Adherence to the first-AUG rule when a second AUG codon follows closely upon the first

M Kozak. Proc Natl Acad Sci U S A. 1995.

Erratum in

Abstract

The rule that eukaryotic ribosomes initiate translation exclusively at the 5' proximal AUG codon is abrogated under rare conditions. One circumstance that has been suggested to allow dual initiation is close apposition of a second AUG codon. A possible mechanism might be that the scanning 40S ribosomal subunit flutters back and forth instead of stopping cleanly at the first AUG. This hypothesis seems to be ruled out by evidence presented herein that in certain mRNAs, the first of two close AUG codons is recognized uniquely. To achieve this, the 5' proximal AUG has to be provided with the full consensus sequence; even small departures allow a second nearby AUG codon to be reached by leaky scanning. This context-dependent leaky scanning unexpectedly fails when the second AUG codon is moved some distance from the first. A likely explanation, based on analyzing the accessibility of a far-downstream AUG codon under conditions of initiation versus elongation, is that 80S elongating ribosomes advancing from the 5' proximal start site can mask potential downstream start sites.

PubMed Disclaimer

Similar articles

Cited by

References

    1. J Biol Chem. 1977 Oct 10;252(19):6895-908 - PubMed
    1. Proc Natl Acad Sci U S A. 1983 Aug;80(16):4879-83 - PubMed
    1. Cell. 1986 Jan 31;44(2):283-92 - PubMed
    1. Mol Cell Biol. 1986 Jul;6(7):2704-11 - PubMed
    1. Nature. 1986 Nov 6-12;324(6092):34-8 - PubMed

Publication types

MeSH terms

Substances

LinkOut - more resources