Analysis of oligonucleotide AUG start codon context in eukariotic mRNAs

The AUG start codon context features have been investigated by analyzing eu karyotic mRNAs belonging to various taxonomic groups. The functional releva nce of each specific position surrounding the AUG start codon has been esta blished as a function of the measured shift between base composition observ ed at that particular position, and base composition averaged over all the 5'untranslated regions. A more detailed analysis carried out on human genes belonging to different isochores showed significant isochore-specific feat ures that cannot be explained only by a mutational bias effect. The most re presented heptamers spanning from position -3 to +4 with respect to the ini tiator AUG have been determined for mRNAs belonging to different taxonomic groups and a web page utility has been set up (http://bigarea.area.ba.cnr.i t: 8000/BioWWW/ATG.html) to determine the relative abundance of a user subm itted oligonucleotide context in a given species or taxon. (C) 2000 Elsevie r Science B.V. All rights reserved.