Loss of dlx5a / dlx6a Locus Alters Non-Canonical Wnt Signaling and Meckel's Cartilage Morphology.

The genes encode transcription factors that establish a proximal-distal polarity within neural crest cells to bestow a regional identity during craniofacial development. The expression regions of paralogs are overlapping yet distinct within the zebrafish pharyngeal arches and may also be involved in progressive morphologic changes and organization of chondrocytes of the face. However, how each paralog of , , and affects craniofacial development is still largely unknown. We report here that the average lengths of the Meckel's, palatoquadrate and ceratohyal cartilages in different mutants were altered. Mutants for and , where the entire locus was deleted, have the shortest lengths for all three structures at 5 days post fertilization (dpf). This phenotype was also observed in 14 dpf larvae. Loss of also resulted in increased proliferation of neural crest cells and expression of chondrogenic markers. Additionally, altered expression and function of non-canonical Wnt signaling were observed in these mutants suggesting a novel interaction between locus and non-canonical Wnt pathway regulating ventral cartilage morphogenesis.