A novel mouse desmosomal cadherin family member, desmoglein 1 gamma

The mouse desmogleins are members of the desmosomal cadherin superfamily, and are critical structural components of the desmosome. The genes encoding mouse desmogleins are tightly clustered within 600 kb of chromosome 18, within a desmosomal cadherin gene family also containing the three desmocollin genes. In this study, we have characterized a novel mouse desmoglein gene, highly homologous to both mouse and human Dsg1, designated desmoglein 1 gamma (Dsg1c). Dsg1 gamma shares 83% amino acid identity to the previously described mouse Dsg1, now designated as Dsg1 alpha, and 32% and 40% identity to mouse Dsg2 and 3, respectively. The Dsg1 gamma gene maps within the desmosomal gene cluster, between Dsc1 and Dsg1 alpha. Comparison of its exon-intron structure revealed a high level of evolutionary conservation with related family members. In contrast to Dsg1 alpha and Dsg3 whose expression is largely restricted to the skin, Dsg1 gamma is also expressed in the brain, skeletal muscle, and liver, among other tissues, and is thus more similar to Dsg2 in its tissue distribution. Interestingly, an orthologous Dsg1 gamma was not found in the human genome, suggesting that the desmosomal cadherin gene cluster contracted during mammalian evolution.