Transport and turnover of microtubules in frog neurons depend on the pattern of axonal growth.
The transport of axonal microtubules in growing neurites has been a controversial issue because of clear but conflicting results obtained with fluorescence-marking techniques. We have attempted to resolve the discordance via analysis of the relationship between apparent microtubule translocation and cell adhesion. Neuronal cultures were prepared from Xenopus embryos 1 d after injection of Cy3-conjugated tubulin into one of the blastomeres of two-cell-stage embryos. Anterograde translocation of axonal microtubules was observed in neurons cultured on a laminin-coated surface, in agreement with previously published data for Xenopus embryonic neurons. However, when neuronal cultures were prepared on a concanavalin A-treated surface, the axonal microtubules were stationary, as reported for all other neurons investigated previously. Neuronal cultures prepared on laminin- and concanavalin A-coated surfaces also demonstrated dramatic differences in the pattern of axonal growth, dynamics of axonal microtubules, and response to brefeldin A treatment. Our findings suggest that transport and dynamics of axonal microtubules may be directly affected by the mechanical tension produced by growth cone activity.
Chang
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Department of Physiology and Biophysics, University of Illinois at Chicago, Chicago, Illinois 60612, USA.
Rodionov
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Borisy
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Popov
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D000818:Animals; D001369:Axons / Q000187:drug effects / Q000502:physiology*; D020126:Brefeldin A; D002232:Carbocyanines; D002448:Cell Adhesion / Q000502:physiology; D018929:Cell Culture Techniques / Q000379:methods; D002462:Cell Membrane / Q000502:physiology; D002478:Cells, Cultured; D003208:Concanavalin A; D003517:Cyclopentanes / Q000494:pharmacology; D005456:Fluorescent Dyes; D007797:Laminin; D008845:Microinjections; D008870:Microtubules / Q000378:metabolism*; D009474:Neurons / Q000166:cytology / Q000378:metabolism* / Q000648:ultrastructure; D010777:Photochemistry; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology; D013314:Stress, Mechanical; D013552:Swine; D014404:Tubulin / Q000378:metabolism / Q000494:pharmacology; D014981:Xenopus
D002232:Carbocyanines; D003517:Cyclopentanes; D005456:Fluorescent Dyes; D007797:Laminin; D011500:Protein Synthesis Inhibitors; D014404:Tubulin; C089187:cyanine dye 3; D003208:Concanavalin A; D020126:Brefeldin A