Mutation of Gtf2ird1 from the Williams–Beuren syndrome critical region results in facial dysplasia, motor dysfunction, and altered vocalisations

https://doi.org/10.1016/j.nbd.2011.12.010Get rights and content

Abstract

Insufficiency of the transcriptional regulator GTF2IRD1 has become a strong potential explanation for some of the major characteristic features of the neurodevelopmental disorder Williams–Beuren syndrome (WBS). Genotype/phenotype correlations in humans indicate that the hemizygous loss of the GTF2IRD1 gene and an adjacent paralogue, GTF2I, play crucial roles in the neurocognitive and craniofacial aspects of the disease. In order to explore this genetic relationship in greater detail, we have generated a targeted Gtf2ird1 mutation in mice that blocks normal GTF2IRD1 protein production. Detailed analyses of homozygous null Gtf2ird1 mice have revealed a series of phenotypes that share some intriguing parallels with WBS. These include reduced body weight, a facial deformity resulting from localised epidermal hyperplasia, a motor coordination deficit, alterations in exploratory activity and, in response to specific stress-inducing stimuli; a novel audible vocalisation and increased serum corticosterone. Analysis of Gtf2ird1 expression patterns in the brain using a knock-in LacZ reporter and c-fos activity mapping illustrates the regions where these neurological abnormalities may originate. These data provide new mechanistic insight into the clinical genetic findings in WBS patients and indicate that insufficiency of GTF2IRD1 protein contributes to abnormalities of facial development, motor function and specific behavioural disorders that accompany this disease.

Highlights

► Detailed analysis of Gtf2ird1 knockout showing physical and neurological defects. ► Facial deformity parallels craniofacial abnormality in Williams–Beuren syndrome. ► Knockout mice produce a novel vocalisation in response to specific stress. ► Expression analysis and immediate early gene induction identify key affected brain regions.

Introduction

Williams–Beuren syndrome (WBS) is a complex multisystem neurodevelopmental disorder characterised by multiple physical and neurological abnormalities (Francke, 1999, Jarvinen-Pasley et al., 2008, Mervis et al., 2000, Meyer-Lindenberg et al., 2004, Morris and Mervis, 2000, Porter et al., 2007), with an estimated incidence of 1 in 7500 (Stromme et al., 2002). It is caused by the hemizygous deletion of a 1.5 Mb region within chromosome 7q11.23 containing 28 genes, called the Williams syndrome critical region (WSCR).

The craniofacial phenotype typically involves a set of hard and soft tissue abnormalities that are commonly used as a clinical diagnostic indicator for WBS. The hard tissue abnormalities include slight alterations in the growth of the cranium and angles of the maxilla and mandible as well as small and missing teeth (Axelsson, 2005, Axelsson et al., 2005). The soft tissue defects are generally described as full lips, a wide smile, full cheeks, periorbital fullness, epicanthal folds, anteverted nares long filtrum and low set ears (Mass and Belostoky, 1993).

WBS patients suffer from a characteristic set of cognitive and behavioural impairments, collectively called the Williams syndrome cognitive profile (WSCP), which includes mental retardation (Morris et al., 1988), a visuospatial construction deficit and a weakness in motor functions (Hocking et al., 2008, Mervis and Klein-Tasman, 2000). The most striking behavioural feature is a lack of social inhibition that results in inappropriate approach to strangers and enhanced emotional empathy (Jarvinen-Pasley et al., 2008). These pathologies indicate that a complex set of brain dysfunctions are associated with the WBS deletion and specific genes within the WSCR play important roles in the normal development and function of the brain.

To determine which genes are candidates for such brain deficiencies, patients with atypical WBS deletions, who have deletions of smaller groups of genes within the WSCR have been identified (Antonell et al., 2009, Botta et al., 1999, Doyle et al., 2004, Edelmann et al., 2007, Gagliardi et al., 2003, Hirota et al., 2003, Karmiloff-Smith et al., 2003, Morris et al., 2003, Osborne and Pober, 2001, Tassabehji et al., 1999, Tassabehji et al., 2005). Correlation of atypical deletions with their corresponding phenotypes has mapped many of the WBS characteristics to GTF2IRD1 and GTF2I, including the craniofacial abnormalities and the neurocognitive profile (Antonell et al., 2009, Doyle et al., 2004, Hirota et al., 2003, Karmiloff-Smith et al., 2003).

Here we conduct a comprehensive analysis of the consequences of a targeted exon 2 mutant allele — Gtf2ird1tm1Hrd in mice, in which we have recently established the transcriptional and translational consequences of the mutation (Palmer et al., 2010). We show that Gtf2ird1tm1Hrd mice have a soft tissue facial abnormality, abnormal motor coordination and motor activity, a novel audible vocalisation phenotype and increased use of both audible and ultrasonic vocalisations in response to swim stress. These findings are correlated with analysis of the expression of Gtf2ird1 in the brain and analysis of c-fos expression following swim stress, which indicates the brain regions that potentially underpin these phenotypes.

Section snippets

Animals

Gtf2ird1tm1Hrd and Gtf2ird1tm2(lacZ)Hrd mice were maintained on a C57BL/6J background as reported previously (Palmer et al., 2007, Palmer et al., 2010) and all experimental comparisons were made between siblings generated by crossing heterozygous mutant parents. Gtf2ird1tm1Hrd homozygous knockout and wild-type mice were kept at 22 ± 1 °C on a 12 h light/dark cycle with free access to food and water. Adult mice were 2–16 months at time of testing. All procedures were approved by the Howard Florey

Homozygous Gtf2ird1tm1Hrd adult mice have a significant weight deficit

Comparison of homozygous Gtf2ird1tm1Hrd null mice with wild type siblings showed that in males, the mutation significantly affected body weight (F(1,41) = 31.63, p < 0.0001) as did age (F(1,41) = 2636.73, p < 0.0001), with a genotype × age interaction (F(1,41) = 28.12, p < 0.0001). Post-hoc tests showed the weight deficit was significant in the adults (Table 1; p < 0.0001). In females, weight was also significantly affected by the homozygous gene mutation (F(1,62) = 39.55, p < 0.0001), as well as age (F(1,62) = 

Discussion

Interest in the function of the Gtf2ird1 gene and its relationship to the abnormalities of WBS has led to five separate reports of Gtf2ird1 mutations in the mouse, including the mouse line described here (Enkhmandakh et al., 2009, Palmer et al., 2007, Palmer et al., 2010, Tassabehji et al., 2005, Young et al., 2008). Null mutants showed some inconsistent phenotypic consequences, the most extreme of which is embryonic lethality (Enkhmandakh et al., 2009). Some variation could be explained by

Acknowledgments

This research was supported by NHMRC Project Grant funding (ECH and AJH) and an ARC Future Fellowship (AJH). The Avisoft recording and analysis equipment was purchased with funding from the Scobie & Claire McKinnon Trust. The c-fos antibody was a kind gift from Professor Michael McKinley. The authors would like to thank Neil Cook for performing initial audible recordings and Robert Gration and Anne Wiltshire for their assistance with initial ultrasound recordings. We also thank Drs Mark Murphy

References (48)

  • M.A. Porter

    The neuropsychological basis of hypersociability in Williams and Down syndrome

    Neuropsychologia

    (2007)
  • S.M. Rhodes

    Executive neuropsychological functioning in individuals with Williams syndrome

    Neuropsychologia

    (2010)
  • G.D. Sales

    Ultrasound and aggressive behaviour in rats and other small mammals

    Anim. Behav.

    (1972)
  • T.P. Sheehan

    Regulation of affect by the lateral septum: implications for neuropsychiatry

    Brain Res. Brain Res. Rev.

    (2004)
  • M. Tassabehji

    Williams syndrome: use of chromosomal microdeletions as a tool to dissect cognitive and physical phenotypes

    Am. J. Hum. Genet.

    (1999)
  • J.M. van Hagen

    Contribution of CYLN2 and GTF2IRD1 to neurological and cognitive symptoms in Williams syndrome

    Neurobiol. Dis.

    (2007)
  • J.W. Anderson

    The production of ultrasonic sounds by laboratory rats and other mammals

    Science

    (1954)
  • A. Antonell

    Partial 7q11.23 deletions further implicate GTF2I and GTF2IRD1 as the main genes responsible for the Williams–Beuren syndrome neurocognitive profile

    J. Med. Genet.

    (2009)
  • S. Axelsson

    Variability of the cranial and dental phenotype in Williams syndrome

    Swed. Dent. J. Suppl.

    (2005)
  • S. Axelsson

    Neurocranial morphology and growth in Williams syndrome

    Eur. J. Orthod.

    (2005)
  • A. Botta

    Detection of an atypical 7q11.23 deletion in Williams syndrome patients which does not include the STX1A and FZD3 genes

    J. Med. Genet.

    (1999)
  • J.N. Crawley

    What's Wrong with my Mouse?: Behavioral Phenotyping of Transgenic and Knockout Mice

    (2007)
  • T.F. Doyle

    “Everybody in the world is my friend” hypersociability in young children with Williams syndrome

    Am. J. Med. Genet. A

    (2004)
  • L. Edelmann

    An atypical deletion of the Williams–Beuren syndrome interval implicates genes associated with defective visuospatial processing and autism

    J. Med. Genet.

    (2007)
  • Cited by (30)

    • Innate frequency-discrimination hyperacuity in Williams-Beuren syndrome mice

      2022, Cell
      Citation Excerpt :

      None of the PD+/− mice tested learned the Go/No-go task after 2 weeks of training (Figure S5A). Within the PD deletion, haploinsufficiency of Gtf2ird1 (Howard et al., 2012; Proulx et al., 2010; Schneider et al., 2012; Young et al., 2008) and Gtf2i (Barak et al., 2019) has been implicated in WBS cognitive symptoms. Individuals with microdeletions including GTF2IRD1 and GTF2I have cognitive deficits like those of persons with WBS (Broadbent et al., 2014; Tassabehji et al., 2005); conversely, those with deletions that exclude these genes have more preserved cognitive function (Antonell et al., 2010; van Hagen et al., 2007; Hirota et al., 2003).

    • Assessment of Multiplex Ligation-Dependent Probe Amplification (MLPA) as a diagnostic test for Egyptian patients with Williams-Beuren syndrome

      2020, Gene Reports
      Citation Excerpt :

      Moreover, the most common characterized craniofacial features were full lips (64%), broad nasal bridge (56%) and periorbital fullness (50%). The craniofacial phenotype typically involves a defect in the growth of the cranium and angles of the maxilla and mandible leading to a characteristic dysmorphic feature elfin face (Howard et al., 2012; Kruszka et al., 2018). In our study, the craniofacial features of the WS deletion patients associated with GTF2IRD1 and BAZ1B genes (Table 1) were mostly similar to other reports (Patil et al., 2012; Fusco et al., 2014; Sharma et al., 2015; Kruszka et al., 2018).

    • Genes dysregulated in the blood of people with Williams syndrome are enriched in protein-coding genes positively selected in humans

      2020, European Journal of Medical Genetics
      Citation Excerpt :

      However, the only clear causative factor identified to date is the gene ELN, whose heterozygous deletion seemingly accounts for the cardiovascular and connective tissue problems suffered by people with the syndrome (Ewart et al., 1993; Milewicz et al., 2000). Regarding the language and cognitive problems, the most promising candidates are GTF2I, GTF2IRD1, BAZ1B, and LIMK1, although their exact role in the etiopatogenesis of WS is not clear-cut (Morris et al., 2003; Tassabehji et al., 2005; Gray et al., 2006; Smith et al., 2009; Sakurai et al., 2011; Howard et al., 2012; Hoeft et al., 2014 for discussion). This complex scenario suggests that most of the distinctive features of WS might result from dosage changes in the genes that are regulated, or interact with, the genes that are deleted in this condition.

    • miR-184 is Critical for the motility-related PNS development in Drosophila

      2015, International Journal of Developmental Neuroscience
      Citation Excerpt :

      Other researches also supported miR-184 was nervous system related (Emdad et al., 2014; Foley et al., 2010; Nomura et al., 2008), suggesting miR-184 play important roles in neural development. With abovementioned information of expression pattern, we determined that locomotor deficit (Howard et al., 2012; Wang et al., 2014) in miR-184 KO mutant could be associated with nervous system dysplasia. Then a nervous system specific driver elav-GAL4 (Table 1) was crossed to UAS-GFP-mir-184 transgenic line, with the aim of generating the over-expression model in which miR-184 was over-abundant in all neurons.

    • Anxious, hypoactive phenotype combined with motor deficits in Gtf2ird1 null mouse model relevant to Williams syndrome

      2012, Behavioural Brain Research
      Citation Excerpt :

      Importantly, mice with partial deletion of the syntenic region lacking genes from Gtf2i to Limk1 (including Gtf2ird1), showed decreased motor coordination and increased anxiety [31], and our study investigates just one of the genes, Gtf2ird1, from the region whose disruption gives rise to these pathologies. Although the use of separate breeding lines, and thus non-littermate wild-type controls, means that we cannot rule out the possibility that subtle differences in genetic background or epigenetic factors between the mice could have influenced the results, several factors suggest that these phenotypes are due to lack of Gtf2ird1: the findings were seen in several cohorts and in relatively large sample sizes; were highly statistically significant; and importantly many aspects involving growth, craniofacial development, motor coordination and anxiety have been recently replicated in the Gtf2ird1tm1Hrd model on a different genetic background [73], with motor deficits also present in the Gtf2ird1tm1Lro model (L. Osborne personal communication). In conclusion, the Gtf2ird1 null mice show evidence of abnormalities that are compatible with some of the clinical symptoms of human patients with Williams–Beuren syndrome: defects in motor coordination, a variable degree of gait abnormalities, and anxiety.

    View all citing articles on Scopus
    View full text