POSTTRANSCRIPTIONAL GENE REGULATORY MECHANISMS IN EUKARYOTES - AN OVERVIEW

Expression of a gene can be controlled at many levels, including trans cription, mRNA splicing, mRNA stability, translation and post-translat ional events such as protein stability and modification. The majority of studies to date have focused on transcriptional control mechanisms, but the importance of post-transcriptional mechanisms in regulating g ene expression in eukaryotes is becoming increasingly clear. In this s hort review, selected examples of post-transcriptional gene regulatory mechanisms operating in both lower and higher eukaryotes will be used to highlight the plethora of such mechanisms already identified. The underlying theme is that post-transciptional gene regulation relies on specific RNA-protein interactions that either result in the targeted degradation of the mRNA or prevent access of the ribosome to the trans lation start codon. Such interactions can occur in the 5' or 3' untran slated regions of an mRNA or within the decoded portion of the molecul e. The importance of these regulatory mechanisms in a range of biologi cal systems is also illustrated.