Inherent Instability of Plasminogen Activator Inhibitor Type 2 mRNA Is Regulated by Tristetraprolin

Abstract

Plasminogen activator inhibitor type 2 (PAI-2) is a serine protease inhibitor that is subject to regulation at the post-transcriptional level. At least two mRNA instability elements reside within the PAI-2 transcript; one in the coding region and another within the 3-untranslated region (UTR). For the latter, a functional AU-rich motif (ARE) has been identified that provides a binding site for a number of cellular proteins, including the mRNA stability protein, HuR. In this study, we used the yeast three-hybrid system to screen a human leukocyte cDNA library to identify other proteins that associate with the PAI-2 ARE. This screen identified tristetraprolin (TTP) as a PAI-2 mRNA ARE-binding protein. UV cross-linking and immunoprecipitation experiments showed that TTP expressed in HEK293 cells could associate with the PAI-2 ARE in vitro. Co-transfection of plasmids expressing TTP and PAI-2 in HEK293 cells resulted in an increase in the decay rate of PAI-2 mRNA and loss of PAI-2 protein in a process that was dependent upon the PAI-2 3-UTR. The 29-nt PAI-2 AU-rich element alone was also capable of conferring TTP-dependent mRNA instability to a reporter transcript. The extent of PAI-2 mRNA stability was remarkably sensitive to TTP since TTP-dependent PAI-2 mRNA decay occurred at TTP levels that were below Western blot detection limits. This study identifies TTP as a functional PAI-2 ARE-binding protein that modulates the post-transcriptional regulation of the PAI-2 gene.

Stability and Translation of TCR ζ mRNA Are Regulated by the Adenosine-Uridine-Rich Elements in Splice-Deleted 3′ Untranslated Region of ζ-Chain

“…The 3Ј UTR of mRNAs plays an important role in regulating gene expression at the posttranscriptional level (21,(25)(26)(27)(28). For example, a 171 bp region in the 3Ј UTR of utrophin mRNA regulates its stability (38,39).…”

“…The 3Ј UTRs of eukaryotic mRNAs play an important role in regulating gene expression at the posttranscriptional level by modulating nucleocytoplasmic mRNA transport, polyadenylation status, subcellular targeting, translation efficiency, stability and rates of degradation (21,(25)(26)(27)(28). The length of 3Ј UTR observed in human mRNAs may range from 21 nt to 8.5 kb with an average of 0.5-0.7 kb (29,30).…”

Decreased Stability and Translation of T Cell Receptor ζ mRNA with an Alternatively Spliced 3′-Untranslated Region Contribute to ζ Chain Down-regulation in Patients with Systemic Lupus Erythematosus

“…The 3Ј UTR of mRNAs play important roles in regulating gene expression at the post-transcriptional level (23,24,(33)(34)(35). To date, the minimum and maximum lengths of 3Ј UTR observed in human mRNAs are 21 nucleotides and 8.5 kb, respectively, and average length is 0.3-0.7 kb (32,36).…”

Transcriptional and posttranscriptional regulation of the plasminogen activator system

“…Mutagenesis of this element partiallys tabilized the normallyu nstable PA I-2 mRNA, hencer evealing af unctional role for this motif ( 237,238). The element also provides binding sites for several ARE binding proteins, including the stabilizing protein HuR (238) and the mRNA destabilizing protein tristetraprolin (TTP), the latter identified from ayeastthreehybrid screen (239). HuR is a membero ft he Hu familyo fm RNAb indingp roteinsa nd has beenassociatedwith promotionofmRNAstability (240)(241)(242).…”