Maxillary Arches of Mouse Dlx1/2 Mutants: Region-Specific Reduction in Cell Proliferation

Cleft palate is one of the most common birth defects in humans. Research in mice shows that Dlx gene mutations cause congenital craniofacial deformities, including cleft palate. Dlx1 and Dlx2 are expressed in the maxillary arch, which gives rise to the palatal shelves of the secondary palate during fetal development. In the wild type, the secondary palate forms to divide the nasal cavity from the oral cavity, while in the Dlx1/2^-/- mutant, severe growth deficiency of the palatal shelves results in the cleft secondary palate. Objective: The aim of this study was to determine whether the growth deficiency of the palatal shelves in Dlx1/2^-/- mutant mice is due to decreased cell proliferation in the maxillary arch. Methods: Immunofluorescence staining, photographic and quantitative analysis were used to compare the maxillary arch in frozen section of wild type and mutant mice embryos. Results: We found that there is reduced cell proliferation in the posterior portion of the medial maxillary arch, where the palatal shelves form, but not in the lateral domain. Conclusion: Our research suggests that reduced cell proliferation in the maxillary arch is an important mechanism behind the cleft palate phenotype of the Dlx1/2^-/- mutant.