Intrinsic polarity of mammalian neuroepithelial cells.
Progenitor cells in the mammalian forebrain can undergo either symmetric or asymmetric cell divisions by varying their cleavage orientation. In asymmetric divisions, cells distribute apically and basally localized proteins differentially to their daughters. Here we explore the intrinsic polarity of neuroepithelial cells in the developing telencephalon. Actin microfilaments are concentrated apically, forming beltlike structures that encircle spots of gamma-tubulin immunoreactivity. Staining for N-cadherin, beta-catenin, and the tyrosine kinase substrates pp120 and paxillin is also enriched at the lumenal surface, presumably due to the localization of these proteins at adherens junctions. Phosphotyrosine immunoreactivity is concentrated apically in rings, suggesting that adherens junctions are enriched for signaling molecules. In mitotic cells it appears that adherens junction proteins and phosphotyrosine immunoreactivity may be inherited either symmetrically or asymmetrically, depending on the cell's cleavage orientation during mitosis. The differential inheritance of junctional proteins may determine whether a daughter cell can respond to extrinsic signals after mitosis.
Department of Biological Sciences, Stanford University, Stanford, California, 94305, USA.
A
A
Chenn
Y A
YA
Zhang
B T
BT
Chang
S K
SK
McConnell
D008841:Actin Cytoskeleton / Q000648:ultrastructure; D000199:Actins / Q000032:analysis; D000818:Animals; D015820:Cadherins / Q000032:analysis; D015815:Cell Adhesion Molecules / Q000032:analysis; D016764:Cell Polarity; D002552:Cerebral Ventricles; D003598:Cytoskeletal Proteins / Q000032:analysis; D004847:Epithelial Cells / Q000737:chemistry / Q000166:cytology; D005289:Ferrets / Q000196:embryology; D005326:Fetal Proteins / Q000032:analysis; D051417:Focal Adhesion Kinase 1; D051416:Focal Adhesion Protein-Tyrosine Kinases; D007365:Intercellular Junctions / Q000648:ultrastructure*; D008870:Microtubules / Q000648:ultrastructure; D008938:Mitosis; D009419:Nerve Tissue Proteins / Q000032:analysis*; D051419:Paxillin; D010750:Phosphoproteins / Q000032:analysis; D010766:Phosphorylation; D019000:Phosphotyrosine / Q000032:analysis; D011499:Protein Processing, Post-Translational; D011505:Protein-Tyrosine Kinases / Q000032:analysis; D051381:Rats; D015398:Signal Transduction; D013687:Telencephalon / Q000737:chemistry / Q000166:cytology* / Q000196:embryology; D015534:Trans-Activators; D014404:Tubulin / Q000032:analysis; D051176:beta Catenin
D000199:Actins; D015820:Cadherins; D015815:Cell Adhesion Molecules; C495268:Ctnnb1 protein, rat; D003598:Cytoskeletal Proteins; D005326:Fetal Proteins; D009419:Nerve Tissue Proteins; D051419:Paxillin; D010750:Phosphoproteins; C496063:Pxn protein, rat; D015534:Trans-Activators; D014404:Tubulin; D051176:beta Catenin; D019000:Phosphotyrosine; D011505:Protein-Tyrosine Kinases; D051417:Focal Adhesion Kinase 1; D051416:Focal Adhesion Protein-Tyrosine Kinases; C496052:Ptk2 protein, rat