Immunohistochemical Localization of YAP and TAZ in Mouse Parotid GlandMorphogenesis

The Hippo pathway is a major regulator of organ size and tissue homeostasis. Yes-associated protein（YAP）and Transcriptional co-activator with PDZ binding motif （TAZ）are essential downstream effectors of the Hippo signaling pathway, and they can translocate into the nucleus to induce the expression of genes for cell growth and proliferation mediated by Transcriptional enhanced associate domain（TEAD）. Branching organs that are similar in embryology, such as salivary glands, mammary glands, pancreas, kidneys, lungs, and lacrimal glands, undergo a series of key events that are conserved throughout the tissue, namely, initiation, tubulogenesis, branching morphogenesis, cell differentiation, and homeostasis. The purpose of this study was to investigate the localization patterns of YAP and TAZ proteins in the morphogenesis of the parotid gland in ICR mice at E16, E18, and E20 by immunohistochemistry, and to clarify their roles. During the development of the fetal parotid gland, the localization of YAP and TAZ was similar. YAP and TAZ proteins were expressed in the salivary epithelium and mesenchyme from E16. At E20, these proteins were expressed in the ductal epithelium, not in the acinar cells. These results suggest that YAP and TAZ proteins are involved in the morphogenesis of the parotid gland in mouse embryos, promoting branching, cell proliferation, and duct formation.