Cleft lip and cleft palate in knockout mice is associated with alterations in epithelial-mesenchymal crosstalk.

Cleft lip is one of the most common human birth defects. However, there remain a limited number of mouse models of cleft lip that can be leveraged to characterize the genes and mechanisms that cause this disorder. Crosstalk between epithelial and mesenchymal cells underlies formation of the face and palate, but the basic molecular events mediating this crosstalk remain poorly understood. We previously demonstrated that mice lacking the epithelial-specific splicing factor have fully penetrant bilateral cleft lip and palate. In this study, we further investigated the mechanisms leading to cleft lip as well as cleft palate in both existing and new mutant mouse models. These studies included a detailed transcriptomic analysis of changes in ectoderm and mesenchyme in embryos during face formation. We identified altered expression of genes previously implicated in cleft lip and/or palate, including components of multiple signaling pathways. These findings provide the foundation for detailed investigations using mutant disease models to examine gene regulatory networks and pathways that are essential for normal face and palate development - the disruption of which leads to orofacial clefting in human patients.