AUF1 p42 isoform selectively controls both steady-state and PGE2-induced FGF9 mRNA decay

Abstract

Fibroblast growth factor 9 (FGF9) is an autocrine/paracrine growth factor that plays vital roles in many physiologic processes including embryonic development. Aberrant expression of FGF9 causes human diseases and thus it highlights the importance of controlling FGF9 expression; however, the mechanism responsible for regulation of FGF9 expression is largely unknown. Here, we show the crucial role of an AU-rich element (ARE) in FGF9 3′-untranslated region (UTR) on controlling FGF9 expression. Our data demonstrated that AUF1 binds to this ARE to regulate FGF9 mRNA stability. Overexpression of each isoform of AUF1 (p37, p40, p42 and p45) showed that only the p42 isoform reduced the steady-state FGF9 mRNA. Also, knockdown of p42AUF1 prolonged the half-life of FGF9 mRNA. The induction of FGF9 mRNA in prostaglandin (PG) E2-treated human endometrial stromal cells was accompanied with declined cytoplasmic AUF1. Nevertheless, ablation of AUF1 led to sustained elevation of FGF9 expression in these cells. Our study demonstrated that p42AUF1 regulates both steady-state and PGE2-induced FGF9 mRNA stability through ARE-mediated mRNA degradation. Since almost half of the FGF family members are ARE-containing genes, our findings also suggest that ARE-mediated mRNA decay is a common pathway to control FGFs expression, and it represents a novel RNA regulon to coordinate FGFs homeostasis in various physiological conditions.

Absence of inactivating mutations and deletions in the DMRT1 and FGF9 genes in a large cohort of 46,XY patients with gonadal dysgenesis

“…An adenylate/uridylate-rich element (ARE) in the FGF9 3'UTR was recently shown to be crucial in the control of FGF9 expression [25]. Mutations in these regulatory elements might cause a reduction in FGF9 expression and secondarily might affect normal male gonadal development.…”

Assembly of Functional Ribonucleoprotein Complexes by AU-rich Element RNA-binding Protein 1 (AUF1) Requires Base-dependent and -independent RNA Contacts

“…Mammalian ␤-globin (␤G) reporter plasmids pTRER␤-wt and pTRER␤-ARE 38 were described previously (21). Plasmid pTRER␤-RAR was constructed by inserting a DNA duplex encoding the R␤ 17 -ARE 16 -R␤ 17 RNA substrate (Table 1) into the BglII site of pTRER␤-wt, thus positioning the R␤ 17 -ARE 16 -R␤ 17 sequence within the reporter mRNA 3Ј-UTR. All plasmid constructs were verified by restriction digest and automated sequencing.…”

“…1, A, right panel, and B, left panel). By fluorescence anisotropy, His 6 -p37 AUF1 binding to the ARE 16 -Fl substrate alone was weak but detectable (Fig. 1B, right panel).…”

“…Inner filter effects and photobleaching were insignificant under these conditions (data not shown). E FRET was calculated from the fluorescence of the donor in the presence (F DA ) or absence (F D ) of the FRET acceptor using Equation 16, where f represents the labeling efficiency of the Cy3 acceptor dye for each double-labeled RNA ligand (21).…”

“…The p37 AUF1 and p40 AUF1 isoforms lack a 49-amino acid sequence near the C terminus encoded by exon 7, whereas p37 AUF1 and p42 AUF1 lack a 19-amino acid domain immediately N-terminal of RRM1 that is encoded by exon 2. However, although sharing common canonical RNA binding domains, the various AUF1 isoforms exhibit distinct subcellular localization profiles (8 -11), diverse RNA binding affinities and effects on the structure of RNA ligands (12), and isoform-specific influences on the decay of mRNA targets (13)(14)(15)(16)(17).…”