ROLE OF UNTRANSLATED REGIONS IN MESSENGER -RNA TRANSLATION AND STABILITY

The biochemical life of mRNA migrating from the nucleus to the cytopla sm is controled by numerous interactions with regulatory proteins. Mos t of those steps are under the control of the 5' and 3' untranslated r egions interacting with specific regulatory proteins and directing tra nsport, translation and stabilization of the mRNA. Similar to DNA, mRN A carry cis-acting sequences allowing the cell to respond to numerous endogenous trans-acting factors able to adapt translation of the messa ge to different physiopathological situations. These regulatory elemen ts could be compared to promoting and enhancing transcriptional sequen ces. The remaining question is: do mRNA really have promoters?