Loss of neurofilaments alters axonal growth dynamics

Kimberly L. Walker, Hee Kwang Yoo, Jayanthi Undamatla, Ben G. Szaro

Research output: Contribution to journalArticle

50 Citations (Scopus)

Abstract

The highly regulated expression of neurofilament (NF) proteins during axon outgrowth suggests that NFs are important for axon development, but their contribution to axon growth is unclear. Previous experiments in Xenopus laevis embryos demonstrated that antibody-induced disruption of NFs stunts axonal growth but left unresolved how the loss of NFs affects the dynamics of axon growth. In the current study, dissociated cultures were made from the spinal cords of embryos injected at the two-cell stage with an antibody to the middle molecular mass NF protein (NF-M), and time-lapse videomicroscopy was used to study early neurite outgrowth in descendants of both the injected and uninjected blastomeres. The injected antibody altered the growth dynamics primarily in long neurites (>85 μm). These neurites were initiated just as early and terminated growth no sooner than did normal ones. Rather, they spent relatively smaller fractions of time actively extending than normal. When growth occurred, it did so at the same velocity. In very young neurites, which have NFs made exclusively of peripherin, NFs were unaffected, but in the shaft of older neurites, which have NFs that contain NF-M, NFs were disrupted. Thus growth was affected only after NFs were disrupted. In contrast, the distributions of α-tubulin and mitochondria were unaffected; thus organelles were still transported into neurites. However, mitochondrial staining was brighter in descendants of injected blastomeres, suggesting a greater demand for energy. Together, these results suggest a model in which intra-axonal NFs facilitate elongation of long axons by making it more efficient.

Original languageEnglish (US)
Pages (from-to)9655-9666
Number of pages12
JournalJournal of Neuroscience
Volume21
Issue number24
StatePublished - Dec 15 2001
Externally publishedYes

Fingerprint

Intermediate Filaments
Neurites
Growth
Axons
Blastomeres
Antibodies
Embryonic Structures
Peripherins
Neurofilament Proteins
Video Microscopy
Xenopus laevis
Tubulin
Organelles
Spinal Cord
Mitochondria
Staining and Labeling

Keywords

  • Mitochondria
  • Neurite outgrowth
  • Neurofilaments
  • Spinal cord
  • Time-lapse videomicroscopy
  • Xenopus laevis

ASJC Scopus subject areas

  • Neuroscience(all)

Cite this

Walker, K. L., Yoo, H. K., Undamatla, J., & Szaro, B. G. (2001). Loss of neurofilaments alters axonal growth dynamics. Journal of Neuroscience, 21(24), 9655-9666.

Loss of neurofilaments alters axonal growth dynamics. / Walker, Kimberly L.; Yoo, Hee Kwang; Undamatla, Jayanthi; Szaro, Ben G.

In: Journal of Neuroscience, Vol. 21, No. 24, 15.12.2001, p. 9655-9666.

Research output: Contribution to journalArticle

Walker, KL, Yoo, HK, Undamatla, J & Szaro, BG 2001, 'Loss of neurofilaments alters axonal growth dynamics', Journal of Neuroscience, vol. 21, no. 24, pp. 9655-9666.
Walker KL, Yoo HK, Undamatla J, Szaro BG. Loss of neurofilaments alters axonal growth dynamics. Journal of Neuroscience. 2001 Dec 15;21(24):9655-9666.
Walker, Kimberly L. ; Yoo, Hee Kwang ; Undamatla, Jayanthi ; Szaro, Ben G. / Loss of neurofilaments alters axonal growth dynamics. In: Journal of Neuroscience. 2001 ; Vol. 21, No. 24. pp. 9655-9666.
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