title: Tenascin-R induces actin-rich microprocesses and branches along neurite shafts.
abstract: The formation of protrusions along the shaft of neurites might be important in the establishment and refinement of neuronal connections during development. In a search for extracellular signals that affect the formation of microprocesses along neurites we found that the ECM glycoprotein tenascin-R (TN-R) but not other ECM glycoproteins increased the percentage of tectal neurons with actin-rich microprocesses and side branches. Longer actin-based microprocesses were also invaded by microtubuli in their proximal part. The formation of microprocesses by TN-R extending laterally along the neuritic shaft was time- and dose-dependent. In addition to the induction of microprocesses, TN-R increased the size of the growth cone of tectal neurons. A cross-species experiment in combination with blocking antibodies demonstrated that the TN-R-induced effects are mediated by the Ig superfamily member contactin. These observations suggest that TN-R via its neuronal receptor contactin might induce a transition from long-distance growth of tectal interneurons to differentiation, including the formation of microprocesses.
authors.affiliation: Max-Delbrück-Centrum für Molekulare Medizin, Robert-Rössle-Strasse 10, D-13092 Berlin, Germany. uzachar@mdc-berlin.de
authors.forename: Ute
authors.initials: U
authors.lastname: Zacharias
authors.forename: Roland
authors.initials: R
authors.lastname: Leuschner
authors.forename: Ursel
authors.initials: U
authors.lastname: Nörenberg
authors.forename: Fritz G
authors.initials: FG
authors.lastname: Rathjen
mesh_terms: D000199:Actins / Q000187:drug effects / Q000378:metabolism*; D000818:Animals; D015816:Cell Adhesion Molecules, Neuronal / Q000187:drug effects / Q000378:metabolism*; D002451:Cell Compartmentation / Q000502:physiology; D002454:Cell Differentiation / Q000187:drug effects / Q000502:physiology*; D048429:Cell Size / Q000187:drug effects / Q000502:physiology; D002478:Cells, Cultured; D002642:Chick Embryo; D058966:Contactins; D020439:Growth Cones / Q000187:drug effects / Q000378:metabolism / Q000648:ultrastructure; D007150:Immunohistochemistry; D008870:Microtubules / Q000187:drug effects / Q000378:metabolism*; D016501:Neurites / Q000187:drug effects / Q000378:metabolism / Q000648:ultrastructure*; D011956:Receptors, Cell Surface / Q000187:drug effects / Q000378:metabolism; D013477:Superior Colliculi / Q000166:cytology / Q000187:drug effects / Q000196:embryology*; D019063:Tenascin / Q000378:metabolism* / Q000494:pharmacology
chemical_list: D000199:Actins; D015816:Cell Adhesion Molecules, Neuronal; D058966:Contactins; D011956:Receptors, Cell Surface; D019063:Tenascin; C074638:tenascin R