The Role of Fat Signalling in Craniofacial Development

About this book

Fat/Dachsous signalling regulates planar cell polarity (PCP), which is the polarisation of tissue structures perpendicular to the apical-basal axis, and interacts with the Hippo pathway to suppress overgrowth of tissues in Drosophila. Recent studies in vertebrates have implicated Fat4 and Dchsl, the receptor-ligand pair and the vertebrate homologues of Drosophila Ft and Ds, respectively, in regulating PCP in the kidney and cochlea. However, the role of Fat signalling is largely undetermined in vertebrate development. To determine the role of Fat signalling in craniofacial development, a basic characterisation was carried out using histology, OPT scanning, skeletal preparations, immunohistochemistry and in situ hybridisations. This revealed that loss of Fat4 and/or Dchs 1 results in arrested growth of salivary glands, disruption of hair polarity of the utricle, delayed differentiation of osteoblasts of the cranial bones and arrested lateral tangential migration of the Facial Branchiomotor neurons (FBNs). In Drosophila and vertebrates, PCP is controlled by two pathways; the Frizzled-PCP and the Fat-PCP pathway. During development, FBNs undergo tangential caudal and lateral tangentia…