Microfilament and microtubule organization and dynamics in process extension by central glia-4 oligodendrocytes: Evidence for a microtubule organizing center

M Rumsby, F Afsari, M Stark, E Hughson

Research output: Contribution to journalArticlepeer-review

Abstract

Microfilaments in freshly adhering CG-4 cells and differentiated CG-4 oligodendrocytes are concentrated at the tips and edges of rapidly forming processes while microtubules are concentrated in new processes and extend from a concentrated spot of alpha-tubulin staining in the cell body to the cell periphery. In motile bipolar CG-4 cells, microfilaments are heavily concentrated at the flattened end of one process and along the rim of processes and the cell body: microtubules are concentrated along main processes and splay out into process tips and the cell body. In differentiated CG-4 oligodendrocytes, microfilaments are concentrated at the many process tips, in filopodia and in fine processes, but are not obvious in main processes where separate bundles of microtubules, which diverge at process branch points, are concentrated. gamma-tubulin, involved in microtubule nucleation, is concentrated at a small discrete area in the cell body, indicative of a microtubule organizing center. Polymerization of both actin and tubulin is required for initial process elaboration. Depolymerization of microtubules, but not of microfilaments, causes complete retraction of bipolar CG-4 cell processes. This process retraction does not occur if microfilaments are depolymerized first, indicating that process extension/retraction in motile bipolar CG-4 cells may occur by a balance of motor protein-driven forces as suggested for growth cone motility. Cytoskeleton organization in CG-4 cells is very similar to that reported for oligodendrocytes. CG-4 cells are thus a useful model for investigating the signals and mechanisms regulating oligodendrocyte process dynamics.

Original languageEnglish
Pages (from-to)118-129
Number of pages12
JournalGlia
Volume42
Issue number2
DOIs
Publication statusPublished - 15 Apr 2003

Keywords

  • CG-4 cells
  • oligodendrocytes
  • microfilaments
  • microtubules
  • process extension/retraction
  • microtubule organizing center
  • motor protein forces
  • RAT-BRAIN OLIGODENDROCYTES
  • CENTRAL-NERVOUS-SYSTEM
  • CELL-LINE
  • ACTIN CYTOSKELETON
  • MOTOR PROTEINS
  • GAMMA-TUBULIN
  • GROWTH CONES
  • CENTROSOME
  • MYELINATION
  • EXPRESSION

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