Spatial-temporal expressions of Crumbs and Nagie oko and their interdependence in zebrafish central nervous system during early development

Int J Dev Neurosci. 2013 Dec;31(8):770-82. doi: 10.1016/j.ijdevneu.2013.09.005. Epub 2013 Sep 24.


A vast number of apicobasal polarity proteins play essential roles in the polarization and morphogenesis of the neuroepithelia. Crumbs (Crb) type I transmembrane cell-cell adhesion proteins are among these proteins. Five crb genes have been identified in zebrafish. However, their expressional and functional differences during early neural development remain to be fully elucidated. Here, we study the spatial-temporal expression patterns and functions of Crb1, Crb2a, and Crb2b in the central nervous system (CNS) during the neurulation period. We show that: 1, the optic vesicle and undifferentiated retinal neuroepithelium only express Crb2a; 2, Crb1 and Crb2a expressions overlap extensively in the undifferentiated neural tube epithelium; 3, Crb2b expression is the weakest of the three and is restricted to the ventral-most regions of the anterior CNS; and 4, Nok and Crb proteins require each other for their apical localization in neuroepithelium. The commencements of Crb1, Crb2a, and Crb2b expressions follow a spatial-temporal spread from anterior to posterior and from ventral to dorsal and lag behind that of adherens junction components, such as ZO-1 and actin bundles. Genetic and morpholino suppression analyses suggest that in regions where these Crb expressions overlap, they are functionally redundant in maintaining apicobasal polarity of the undifferentiated neuroepithelium.

Keywords: -somite stage; -ss; Apicobasal polarity; CNS; Crb; Crumbs; Lin7c; Nagie oko; Neuroepithelium; Nok; hours postfertilization; hpf; the central nervous system.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Age Factors
  • Animals
  • Animals, Genetically Modified
  • Central Nervous System / cytology
  • Central Nervous System / growth & development*
  • Central Nervous System / metabolism*
  • Gene Expression Regulation, Developmental / genetics
  • Gene Expression Regulation, Developmental / physiology*
  • Guanylate Cyclase / genetics
  • Guanylate Cyclase / metabolism*
  • Membrane Proteins
  • Morpholinos / genetics
  • Morpholinos / metabolism
  • Nerve Tissue Proteins / genetics
  • Nerve Tissue Proteins / metabolism*
  • Zebrafish
  • Zebrafish Proteins / genetics
  • Zebrafish Proteins / metabolism*
  • Zonula Occludens-1 Protein / genetics
  • Zonula Occludens-1 Protein / metabolism


  • Crb1 protein, zebrafish
  • Crb2a protein, zebrafish
  • Membrane Proteins
  • Morpholinos
  • Nerve Tissue Proteins
  • Zebrafish Proteins
  • Zonula Occludens-1 Protein
  • crb2b protein, zebrafish
  • mpp5a protein, zebrafish
  • Guanylate Cyclase