The Drosophila Tis11 protein and its effects on mRNA expression in flies.

Members of the mammalian tristetraprolin family of CCCH tandem zinc finger proteins can bind to certain AU-rich elements (AREs) in mRNAs, leading to their deadenylation and destabilization. Mammals express three or four members of this family, but Drosophila melanogaster and other insects appear to contain a single gene, Tis11. We found that recombinant Drosophila Tis11 protein could bind to ARE-containing RNA oligonucleotides with low nanomolar affinity.

Alternatively expressed domains of AU-rich element RNA-binding protein 1 (AUF1) regulate RNA-binding affinity, RNA-induced protein oligomerization, and the local conformation of bound RNA ligands.

AU-rich element RNA-binding protein 1 (AUF1) binding to AU-rich elements (AREs) in the 3'-untranslated regions of mRNAs encoding many cytokines and other regulatory proteins modulates mRNA stability, thereby influencing protein expression. AUF1-mRNA association is a dynamic paradigm directed by various cellular signals, but many features of its function remain poorly described. There are four isoforms of AUF1 that result from alternative splicing of exons 2 and 7 from a common pre-mRNA.

Protein kinase C activation stabilizes LDL receptor mRNA via the JNK pathway in HepG2 cells.

LDL is the most abundant cholesterol transport vehicle in plasma and a major prognostic indicator of atherosclerosis. Hepatic LDL receptors limit circulating LDL levels, since cholesterol internalized by the liver can be excreted. As such, mechanisms regulating LDL receptor expression in liver cells are appealing targets for cholesterol-lowering therapeutic strategies.

Specific protein domains mediate cooperative assembly of HuR oligomers on AU-rich mRNA-destabilizing sequences.

The RNA-binding factor HuR is a ubiquitously expressed member of the Hu protein family that binds and stabilizes mRNAs containing AU-rich elements (AREs). Hu proteins share a common domain organization of two tandemly arrayed RNA recognition motifs (RRMs) near the N terminus, followed by a basic hinge domain and a third RRM near the C terminus. In this study, we engineered recombinant wild-type and mutant HuR proteins lacking affinity tags to characterize their ARE-binding properties.

Substrate dependence of conformational changes in the RNA-binding domain of tristetraprolin assessed by fluorescence spectroscopy of tryptophan mutants.

Association of tristetraprolin (TTP) with mRNAs containing selected AU-rich mRNA-destabilizing elements (AREs) initiates rapid cytoplasmic degradation of these transcripts. The RNA-binding activity of TTP is mediated by an internal tandem zinc finger domain that preferentially recognizes U-rich RNA ligands containing adjacent UUAU half-sites and is accompanied by conformational changes within the peptide. Here, we have used analogues of the TTP RNA-binding domain containing specific tryptophan substitutions to probe the Zn2+ and RNA substrate dependence of conformational events within individual zinc fingers.

A hairpin-like structure within an AU-rich mRNA-destabilizing element regulates trans-factor binding selectivity and mRNA decay kinetics.

In mammals, rapid mRNA turnover directed by AU-rich elements (AREs) is mediated by selective association of cellular ARE-binding proteins. These trans-acting factors display overlapping RNA substrate specificities and may act to either stabilize or destabilize targeted transcripts; however, the mechanistic features of AREs that promote preferential binding of one trans-factor over another are not well understood. Here, we describe a hairpin-like structure adopted by the ARE from tumor necrosis factor alpha (TNFalpha) mRNA that modulates its affinity for selected ARE-binding proteins.

RNA sequence elements required for high affinity binding by the zinc finger domain of tristetraprolin: conformational changes coupled to the bipartite nature of Au-rich MRNA-destabilizing motifs.

Tristetraprolin (TTP) binds AU-rich elements (AREs) encoded within selected labile mRNAs and targets these transcripts for rapid cytoplasmic decay. RNA binding by TTP is mediated by an approximately 70-amino acid domain containing two tandemly arrayed CCCH zinc fingers. Here we show that a 73-amino acid peptide spanning the TTP zinc finger domain, denoted TTP73, forms a dynamic, equimolar RNA.