ARVCF depletion cooperates with Tbx1 deficiency in the development of 22q11.2DS-like phenotypes in Xenopus.

The 22q11.2 deletion syndrome is a common dominant genetic disorder characterized by a heterozygous deletion of a cluster of genes on chromosome 22q11.2. TBX1, a transcription factor belonging to the T-box gene family, is a key player in the syndrome. However, heterozygosity of Tbx1 in mouse models does not fully recapitulate the phenotypes characteristic of the disease, which may point to the involvement of other genes in the deleted chromosomal region. Hence, we investigated the contribution of the catenin ARVCF, another gene that is deleted in 22q11.2DS. During Xenopus development, ARVCF mRNA is expressed in the pharyngeal arches and depleting either ARVCF or Tbx1 results in delayed migration of the cranial neural crest cells and in defects in the craniofacial skeleton and aortic arches. Moreover, double depletion of ARVCF and Tbx1 revealed that they act cooperatively, indicating that decreased ARVCF levels may also contribute to 22q11.2DS-associated phenotypes.