title: A single element in the 3'UTR of the apical sodium-dependent bile acid transporter controls both stabilization and destabilization of mRNA.
abstract: mRNA stability appears to play a key role in the ontogenic regulation of the apical sodium-dependent bile acid transporter (ASBT). The RNA-binding proteins Hu antigen R (HuR) and tristetraprolin (TTP) stabilize and destabilize ASBT mRNA, respectively. Potential HuR-binding sites were assessed by sequence analysis in the context of prior in vitro functional analyses of the rat ASBT 3'UTR. Wild-type and mutant-binding sites were investigated by gel-shift analysis using IEC-6 cell extracts. The functional consequences of binding site mutations were assessed using two different hybrid reporter constructs linking the 3'UTR element to either a luciferase or a β-globin coding mRNA sequence. A specific metastasis-associated gene 1 (MTA1) cis-element was identified in the ASBT 3'UTR that became associated with proteins in IEC-6 cell extracts and could be supershifted by anti-HuR or anti-TTP antibodies. Mutation of this cis-element abrogated the gel shift of IEC-6 proteins. Furthermore, hybrid constructs containing a mutant MTA1 element had reduced responses to modulation of HuR or TTP. For the first time, we have identified a single specific sequence element in the 3'UTR of the rat ASBT mRNA that mediates counter-regulatory changes in mRNA abundance in response to both HuR and TTP.
authors.affiliation: *Department of Pediatrics, University of Pittsburgh School of Medicine, Pittsburgh, PA 15224, U.S.A.
authors.forename: Dellys M
authors.initials: DM
authors.lastname: Soler
authors.affiliation: *Department of Pediatrics, University of Pittsburgh School of Medicine, Pittsburgh, PA 15224, U.S.A.
authors.forename: Ayantika
authors.initials: A
authors.lastname: Ghosh
authors.affiliation: *Department of Pediatrics, University of Pittsburgh School of Medicine, Pittsburgh, PA 15224, U.S.A.
authors.forename: Frank
authors.initials: F
authors.lastname: Chen
authors.affiliation: *Department of Pediatrics, University of Pittsburgh School of Medicine, Pittsburgh, PA 15224, U.S.A.
authors.forename: Benjamin L
authors.initials: BL
authors.lastname: Shneider
mesh_terms: D020413:3' Untranslated Regions / Q000235:genetics*; D000818:Animals; D001665:Binding Sites; D051959:ELAV Proteins / Q000235:genetics* / Q000378:metabolism; D024202:Electrophoretic Mobility Shift Assay; D005786:Gene Expression Regulation; D029363:Organic Anion Transporters, Sodium-Dependent / Q000235:genetics*; D011506:Proteins / Q000235:genetics / Q000502:physiology*; D020871:RNA Stability / Q000235:genetics*; D012333:RNA, Messenger / Q000235:genetics; D016601:RNA-Binding Proteins / Q000235:genetics; D051381:Rats; D027981:Symporters / Q000235:genetics*; D051816:Tristetraprolin / Q000378:metabolism
chemical_list: D020413:3' Untranslated Regions; D051959:ELAV Proteins; C121683:Mta1 protein, rat; D029363:Organic Anion Transporters, Sodium-Dependent; D011506:Proteins; D012333:RNA, Messenger; D016601:RNA-Binding Proteins; D027981:Symporters; D051816:Tristetraprolin; C071908:sodium-bile acid cotransporter