Molecular events regulating messenger RNA stability in eukaryotes.

The regulation of mRNA turnover plays a major role in the overall control of gene expression. Transcriptional control of eukaryotic gene regulation by external and/or internal stimuli has received considerable attention and the purpose of this review is to highlight recent work elucidating the mechanisms underlying the steady-state levels of mRNAs in the cytoplasm. Protection of mRNA from the action of nucleases as it passes from the nucleus to the ribosomes for translation is achieved, at least in part, by its union with mRNA binding proteins and the presence of poly(A) tail. The half-life of a message represents a balance between the transcriptional activity and intracellular degradative processes. These properties can be modulated by the presence of specific nucleotide sequences in a mRNA along with cis- and trans-acting elements and accompanied by post-translational feed back mechanisms. Presently, various regulatory mechanisms involved in the mRNA decay process are ill-defined. The work described here illustrates the complexity of this emerging field of study and outlines its contribution to our understanding of gene regulation in eukaryotes.