ABSTRACT
Turn-over of messenger ribonucleic acid ( mRNA) is a major control point in gene expres-sion.In mammals,many mRNAs encode inflammatory cytokines ,oncoproteins,and G-protein-coupled receptors are destabilized by the presence of AU -rich elements ( AREs ) in their 3′-untranslated regions .Association of ARE-binding proteins(AUBPs)with these mRNAs promotes rapid mRNA degradation .ARE/poly(U)-binding factor 1(AUF1),one of the best-characterized AUBPs,binds to many ARE-mRNAs and assembles other fac-tors to recruit the mRNA degradation machinery .Most studies support an mRNA -destabilizing role for AUF1,al-though other findings suggest additional functions for this factor .However,several lines of evidence also support a role for AUF1 in the initiation and/or development of cancer .Many AUF1-targeted transcripts encode products that control pro-or anti-oncogenic processes .Numerous signaling pathways alter the composition of this AUF 1 complex of proteins to affect changes in ARE -mRNA degradation rates .This review briefly describes the roles of mRNA decay in gene expression in general and ARE -mediated decay ( AMD) in particular ,with a focus on AUF1 and the different modes of regulation that govern AUF 1 involvement in AMD.In the end,we discuss how changes in AUF1 isoform distribution,subcellular localization,and post-translational protein modifications can influence the metabolism of targeted mRNAs .