title: Par6b regulates the dynamics of apicobasal polarity during development of the stratified Xenopus epidermis.
abstract: During early vertebrate development, epithelial cells establish and maintain apicobasal polarity, failure of which can cause developmental defects or cancer metastasis. This process has been mostly studied in simple epithelia that have only one layer of cells, but is poorly understood in stratified epithelia. In this paper we address the role of the polarity protein Partitioning defective-6 homolog beta (Par6b) in the developing stratified epidermis of Xenopus laevis. At the blastula stage, animal blastomeres divide perpendicularly to the apicobasal axis to generate partially polarized superficial cells and non-polarized deep cells. Both cell populations modify their apicobasal polarity during the gastrula stage, before differentiating into the superficial and deep layers of epidermis. Early differentiation of the epidermis is normal in Par6b-depleted embryos; however, epidermal cells dissociate and detach from embryos at the tailbud stage. Par6b-depleted epidermal cells exhibit a significant reduction in basolaterally localized E-cadherin. Examination of the apical marker Crumbs homolog 3 (Crb3) and the basolateral marker Lethal giant larvae 2 (Lgl2) after Par6b depletion reveals that Par6b cell-autonomously regulates the dynamics of apicobasal polarity in both superficial and deep epidermal layers. Par6b is required to maintain the "basolateral" state in both epidermal layers, which explains the reduction of basolateral adhesion complexes and epidermal cells shedding.
authors.affiliation: Division of Developmental Biology, Cincinnati Children's Research Foundation, Cincinnati, Ohio, United States of America ; Molecular and Developmental Biology Graduate Program, Cincinnati Children's Research Foundation, Cincinnati, Ohio, United States of America.
authors.forename: Sha
authors.initials: S
authors.lastname: Wang
authors.forename: Sang-Wook
authors.initials: SW
authors.lastname: Cha
authors.forename: Aaron M
authors.initials: AM
authors.lastname: Zorn
authors.forename: Christopher
authors.initials: C
authors.lastname: Wylie
mesh_terms: D000818:Animals; D015153:Blotting, Western; D015820:Cadherins / Q000235:genetics / Q000378:metabolism; D016764:Cell Polarity / Q000235:genetics / Q000502:physiology*; D004847:Epithelial Cells / Q000166:cytology / Q000378:metabolism*; D004848:Epithelium / Q000196:embryology / Q000378:metabolism*; D054262:Gastrulation / Q000235:genetics / Q000502:physiology; D018507:Gene Expression Regulation, Developmental; D055785:Gene Knockdown Techniques; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D017403:In Situ Hybridization; D007700:Kinetics; D018613:Microscopy, Confocal; D060172:Morpholinos / Q000008:administration & dosage; D020133:Reverse Transcriptase Polymerase Chain Reaction; D029867:Xenopus Proteins / Q000235:genetics / Q000378:metabolism*; D014982:Xenopus laevis / Q000196:embryology / Q000235:genetics / Q000378:metabolism*; D028961:beta Karyopherins / Q000235:genetics / Q000378:metabolism
chemical_list: C074260:CDH3 protein, Xenopus; D015820:Cadherins; D060172:Morpholinos; C512643:PARD6B protein, Xenopus; D029867:Xenopus Proteins; D028961:beta Karyopherins; C424163:late gestation lung 2 karyopherin; D049452:Green Fluorescent Proteins