An alternative polyadenylation signal in TCF7L2 generates isoforms that inhibit T cell factor-lymphoid-enhancer factor TCF-LEF-dependent target genesReport as inadecuate




An alternative polyadenylation signal in TCF7L2 generates isoforms that inhibit T cell factor-lymphoid-enhancer factor TCF-LEF-dependent target genes - Download this document for free, or read online. Document in PDF available to download.

Diabetologia

, Volume 54, Issue 12, pp 3078–3082

First Online: 14 September 2011Received: 27 May 2011Accepted: 01 August 2011

Abstract

Aims-hypothesisIntronic single nucleotide polymorphisms within the transcription factor 7-like 2 TCF7L2 gene are associated with risk of type 2 diabetes. It is widely hypothesised that the predisposing variation is involved in cis-regulation of TCF7L2 activity. The aim of this study was to seek evidence for the existence of novel TCF7L2 isoforms encoded within the type 2 diabetes-associated genomic region.

MethodsWe searched expressed sequence tag EST databases for novel TCF7L2 transcripts and sought to validate the function and integrity of any isoforms found using a combination of RT-PCR, western blotting and reporter gene techniques.

ResultsAnalysis of EST databases suggested the presence of an alternative polyadenylation site located in intron 4 of TCF7L2. We used 3′ rapid amplification of cDNA ends and real-time PCR to validate the integrity of this polyadenylation signal and show its wide use across human tissues. Western blotting results are consistent with the use of this polyadenylation signal to generate novel protein isoforms. The alternative polyadenylation signal results in the production of isoforms that retain the β-catenin binding domain but do not possess the high-mobility group box DNA-binding domain. Promoter–reporter gene assays suggest that these isoforms inhibit TCF7L2-dependent target genes by sequestering β-catenin.

Conclusions-interpretationWe have identified a novel polyadenylation signal within TCF7L2 that can result in the production of isoforms that act to repress TCF-LEF-dependent target genes. These findings may provide new insights into the association of TCF7L2 with susceptibility to type 2 diabetes.

KeywordsAlternative polyadenylation TCF7L2 Type 2 diabetes AbbreviationsASPAdaptor-specific primer

ESTExpressed sequence tag

GSPGene-specific primer

LDLinkage disequilibrium

mAbMonoclonal antibody

pAbPolyclonal antibody

RACERapid amplification of cDNA ends

SNPSingle nucleotide polymorphism

TCF-LEFT cell factor-lymphoid-enhancer factor

An erratum to this article can be found at http:-dx.doi.org-10.1007-s00125-011-2327-x

Download fulltext PDF



Author: J. M. Locke - G. Da Silva Xavier - G. A. Rutter - L. W. Harries

Source: https://link.springer.com/







Related documents