Analysis of RNA splicing defects in PITX2 mutants supports a gene dosage model of Axenfeld-Rieger syndrome

Nicole L Maciolek; Wallace LM Alward; Jeffrey C Murray; Elena V Semina; Mark T McNally

doi:10.1186/1471-2350-7-59

Back

Analysis of RNA splicing defects in PITX2 mutants supports a gene dosage model of Axenfeld-Rieger syndrome

Journal article

Open access

Peer reviewed

Analysis of RNA splicing defects in PITX2 mutants supports a gene dosage model of Axenfeld-Rieger syndrome

Nicole L Maciolek, Wallace LM Alward, Jeffrey C Murray, Elena V Semina and Mark T McNally

BMC medical genetics, Vol.7(1), pp.59-59

07/11/2006

DOI: 10.1186/1471-2350-7-59

PMCID: PMC1553432

PMID: 16834779

Files and links (1)

url

https://doi.org/10.1186/1471-2350-7-59View

Published (Version of record) Open Access

Abstract

Background: Axenfeld-Rieger syndrome (ARS) is associated with mutations in the PITX2 gene that encodes a homeobox transcription factor. Several intronic PITX2 mutations have been reported in Axenfeld-Rieger patients but their effects on gene expression have not been tested. Methods: We present two new families with recurrent PITX2 intronic mutations and use PITX2c minigenes and transfected cells to address the hypothesis that intronic mutations effect RNA splicing. Three PITX2 mutations have been analyzed: a G>T mutation within the AG 3' splice site (ss) junction associated with exon 4 (IVS4-1G>T), a G>C mutation at position +5 of the 5' (ss) of exon 4 (IVS4+5G>C), and a previously reported A>G substitution at position -11 of 3'ss of exon 5 (IVS5-11A>G). Results: Mutation IVS4+5G>C showed 71% retention of the intron between exons 4 and 5, and poorly expressed protein. Wild-type protein levels were proportionally expressed from correctly spliced mRNA. The G>T mutation within the exon 4 AG 3'ss junction shifted splicing exclusively to a new AG and resulted in a severely truncated, poorly expressed protein. Finally, the A>G substitution at position -11 of the 3'ss of exon 5 shifted splicing exclusively to a newly created upstream AG and resulted in generation of a protein with a truncated homeodomain. Conclusion: This is the first direct evidence to support aberrant RNA splicing as the mechanism underlying the disorder in some patients and suggests that the magnitude of the splicing defect may contribute to the variability of ARS phenotypes, in support of a gene dosage model of Axenfeld-Rieger syndrome.

Details

Title: Subtitle: Analysis of RNA splicing defects in PITX2 mutants supports a gene dosage model of Axenfeld-Rieger syndrome
Creators: Nicole L Maciolek - Department of Microbiology and Molecular Genetics, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI 53226, USA
Wallace LM Alward - Department of Ophthalmology, University of Iowa, Iowa City, IA 52242, USA
Jeffrey C Murray - Department of Pediatrics, University of Iowa, Iowa City, IA 52242, USA
Elena V Semina - Department of Pediatrics, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI 53226, USA
Mark T McNally - Department of Microbiology and Molecular Genetics, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI 53226, USA
Resource Type: Journal article
Publication Details: BMC medical genetics, Vol.7(1), pp.59-59
DOI: 10.1186/1471-2350-7-59
PMID: 16834779
PMCID: PMC1553432
NLM abbreviation: BMC Med Genet
ISSN: 1471-2350
eISSN: 1471-2350
Publisher: BioMed Central; London
Language: English
Date published: 07/11/2006
Academic Unit: Anatomy and Cell Biology; Stead Family Department of Pediatrics; Epidemiology; Pediatric Dentistry; Craniofacial Anomalies Research Center; Dental Research; Ophthalmology and Visual Sciences
Record Identifier: 9984025368002771

Metrics

36 Record Views

22 Times Cited - Web of Science