title: Role of JNK during buccopharyngeal membrane perforation, the last step of embryonic mouth formation.
abstract: The buccopharyngeal membrane is a thin layer of cells covering the embryonic mouth. The perforation of this structure creates an opening connecting the external and the digestive tube which is essential for oral cavity formation. In humans, persistence of the buccopharyngeal membrane can lead to orofacial defects such as choanal atresia, oral synechiaes, and cleft palate. Little is known about the causes of a persistent buccopharyngeal membrane and, importantly, how this structure ruptures.
  
  
  
  We have determined, using antisense and pharmacological approaches, that Xenopus embryos deficient c-Jun N-terminal kinase (JNK) signaling have a persistent buccopharyngeal membrane. JNK deficient embryos have decreased cell division and increased cellular stress and apoptosis. However, altering these processes independently of JNK did not affect buccopharyngeal membrane perforation. JNK deficient embryos also have increased intercellular adhesion and defects in e-cadherin localization. Conversely, embryos with overactive JNK have epidermal fragility, increased E-cadherin internalization, and increased membrane localized clathrin. In the buccopharyngeal membrane, clathrin is colocalized with active JNK. Furthermore, inhibition of endocytosis results in a persistent buccopharyngeal membrane, mimicking the JNK deficient phenotype.
  
  
  
  The results of this study suggest that JNK has a role in the disassembly adherens junctions by means of endocytosis that is required during buccopharyngeal membrane perforation. Developmental Dynamics 246:100-115, 2017. © 2016 Wiley Periodicals, Inc.
authors.affiliation: Department of Biology, Virginia Commonwealth University, Richmond, Virginia.
authors.forename: Nathalie S
authors.initials: NS
authors.lastname: Houssin
authors.affiliation: Department of Human and Molecular Genetics, Virginia Commonwealth University, Richmond, Virginia.
authors.forename: Navaneetha Krishnan
authors.initials: NK
authors.lastname: Bharathan
authors.affiliation: Department of Public Health Sciences, University of Virginia School of Medicine, Charlottesville, Virginia.
authors.forename: Stephen D
authors.initials: SD
authors.lastname: Turner
authors.affiliation: Department of Biology, Virginia Commonwealth University, Richmond, Virginia.
authors.forename: Amanda J G
authors.initials: AJ
authors.lastname: Dickinson
mesh_terms: D022005:Adherens Junctions; D000818:Animals; D015820:Cadherins / Q000378:metabolism; D002610:Cheek; D004705:Endocytosis; D007425:Intracellular Membranes / Q000378:metabolism*; D048031:JNK Mitogen-Activated Protein Kinases / Q000502:physiology*; D009055:Mouth / Q000196:embryology* / Q000254:growth & development; D010614:Pharynx; D014982:Xenopus laevis / Q000196:embryology*
chemical_list: D015820:Cadherins; D048031:JNK Mitogen-Activated Protein Kinases
keywords: JNK; buccopharyngeal membrane; embryonic mouth; intercellular adhesion