Molecular cloning and developmental expression of plakophilin 2 in zebrafish

Armadillo proteins are involved in providing strength and support to cells and tissues, nuclear transport, and transcriptional activation. In this report, we describe the identification and characterisation of the cDNA of the desmosomal armadillo protein plakophilin 2 in zebrafish. The 2448bp coding sequence encodes a predicted 815 amino acid protein, with nine armadillo repeats characteristic of the p120-catenin subfamily. It shares conserved N-glycosylation, myristoylation, and glycogen synthase kinase 3, casein kinase 2, and protein kinase C phosphorylation sites with mammalian armadillo proteins including plakoglobin and beta-catenin. Semi-quantitative reverse transcription polymerase chain reaction and whole mount in situ hybridisation show that it is expressed both maternally and zygotically. It is ubiquitously expressed during blastula stages but becomes restricted to epidermal and cardiac tissue during gastrulation. These results provide evidence that zebrafish plakophilin 2 is developmentally regulated with potential roles in cell adhesion, signalling, and cardiac and skin development.