Translational control of cytokine expression by 3' UA-rich sequences.

Several messenger RNAs which are transiently expressed contain a conserved uridine-adenosine-rich sequence in their 3' untranslated region. Many of these mRNas encode cytokines, growth factors or oncoproteins. This UA-rich sequence is composed of several interpsersed repeats of the octanucleotide UUAUUUAU and plays a key role in the post-transcriptional regulation of these mRNAs. Known as instability determinants, these UA-rich elements can also strongly affect mRNA translational efficiency. In this report, we review the data which illustrate this translational regulation and give insight the underlying mechanism.