T-Box Protein 15 (TBX15)

T-box genes encode a phylogenetically conserved family of transcription factors that regulate a variety of developmental processes. All contain a common DNA-binding domain, the T box.Tbx15 is expressed in the mouse embryo beginning at day 9.5, primarily in the craniofacial region and in the developing limbs. Because the phenotype showed similarities to that of Tbx15-deficient mice, Lausch et al. (2008) screened for mutations in the TBX15 gene in the 2 girls and identified homozygosity for different single-nucleotide deletions at codon 344 in each. Functional experiments indicated that TBX15 protein synthesized from the 2 mutant alleles retained the ability to bind DNA targets in vitro, but that cellular levels of TBX15 were drastically reduced or abolished because of proteasome-associated degradation.