title: Poly(A) tail length-dependent stabilization of GAP-43 mRNA by the RNA-binding protein HuD.
abstract: The neuronal ELAV-like RNA-binding protein HuD binds to a regulatory element in the 3'-untranslated region of the growth-associated protein-43 (GAP-43) mRNA. Here we report that overexpression of HuD protein in PC12 cells stabilizes the GAP-43 mRNA by delaying the onset of mRNA degradation and that this process depends on the size of the poly(A) tail. Using a polysome-based in vitro mRNA decay assay, we found that addition of recombinant HuD protein to the system increased the half-life of full-length, capped, and polyadenylated GAP-43 mRNA and that this effect was caused in part by a decrease in the rate of deadenylation of the mRNA. This stabilization was specific for GAP-43 mRNA containing the HuD binding element in the 3'-untranslated region and a poly(A) tail of at least 150 A nucleotides. In correlation with the effect of HuD on GAP-43 mRNA stability, we found that HuD binds GAP-43 mRNAs with long tails (A150) with 10-fold higher affinity than to those with short tails (A30). We conclude that HuD stabilizes the GAP-43 mRNA through a mechanism that is dependent on the length of the poly(A) tail and involves changes in its affinity for the mRNA.
authors.affiliation: Department of Neurosciences, University of New Mexico School of Medicine, Albuquerque, New Mexico 87131-5223, USA.
authors.forename: Andrea C
authors.initials: AC
authors.lastname: Beckel-Mitchener
authors.forename: Angel
authors.initials: A
authors.lastname: Miera
authors.forename: Rebecca
authors.initials: R
authors.lastname: Keller
authors.forename: Nora I
authors.initials: NI
authors.lastname: Perrone-Bizzozero
mesh_terms: D000818:Animals; D051959:ELAV Proteins; D019922:GAP-43 Protein / Q000235:genetics*; D005786:Gene Expression Regulation; D007700:Kinetics; D009419:Nerve Tissue Proteins / Q000378:metabolism*; D016716:PC12 Cells; D011061:Poly A / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics* / Q000378:metabolism; D016601:RNA-Binding Proteins / Q000378:metabolism*; D051381:Rats
chemical_list: D051959:ELAV Proteins; D019922:GAP-43 Protein; D009419:Nerve Tissue Proteins; D012333:RNA, Messenger; D016601:RNA-Binding Proteins; D011061:Poly A