Abstract

Pitt-Hopkins syndrome (PTHS) is a rare developmental disorder associated with severe mental retardation, facial abnormalities, and intermittent hyperventilation. Autosomal dominant PTHS is caused by mutations in the transcription factor 4 (TCF4) gene, whereas NRXN1 and CNTNAP2 mutations are associated with autosomal recessive PTHS. To determine the impact of missense mutations on TCF4 function, we tested a panel of PTHS-associated mutations using a range of quantitative techniques. Mutations in the basic helix-loop-helix (bHLH) domain of TCF4 alter the subnuclear localization of the mutant protein and can attenuate homo- and heterodimer formation in homogenous time-resolved fluorescence (HTRF) assays. By contrast, mutations proximal to the bHLH domain do not alter the location of TCF4 or impair heterodimer formation. In addition, we show that TCF4 can transactivate the NRXN1β and CNTNAP2 promoters in luciferase assays. Here we find variable, context-specific deficits in the ability of the different PTHS-associated TCF4 mutants to transactivate these promoters when coexpressed with different bHLH transcription factors. These data demonstrate that PTHS-associated missense mutations can have multiple effects on the function of the protein, and suggest that TCF4 may modulate the expression of NRXN1 and CNTNAP2 thereby defining a regulatory network in PTHS.

Links

Publisher Full Text

Authors

Forrest M, Chapman RM, Doyle AM, Tinsley CL, Waite A, Blake DJ

Institution

Institute of Psychological Medicine and Clinical Neurosciences, MRC Centre for Neuropsychiatric Genetics and Genomics, School of Medicine, Cardiff University, Cardiff, UK.

Source

Human mutation 33:12 2012 Dec pg 1676-86

MeSH

Animals
Basic Helix-Loop-Helix Leucine Zipper Transcription Factors
COS Cells
Cell Adhesion Molecules, Neuronal
Cell Nucleus
Cercopithecus aethiops
Facies
Genes, Reporter
HEK293 Cells
Humans
Hyperventilation
Intellectual Disability
Luciferases, Renilla
Membrane Proteins
Mutation, Missense
Nerve Tissue Proteins
Promoter Regions, Genetic
Protein Multimerization
Protein Structure, Tertiary
Protein Transport
Transcription Factors
Transcriptional Activation

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

22777675