The crucial role of the non-coding portion of genomes is now widely acknowl
edged. In particular, mRNA untranslated regions are involved in many post-t
ranscriptional regulatory pathways that control mRNA localization, stabilit
y and translation efficiency. We review in this paper the major structural
and compositional features of eukaryotic mRNA untranslated regions and prov
ide some examples of bioinformatic analyses for their functional characteri
zation. (C) 2001 Published by Elsevier Science B.V.