Journal of Neuroscience, Vol 2, 806-814, Copyright © 1982 by Society for Neuroscience
Analysis of microtubule number and length in cytoskeletons of cultured chick sensory neurons
PC Letourneau
In order to examine the continuity of individual microtubules in growing
neurites, microtubules were observed and counted in whole mounted
cytoskeletons of chick embryo sensory neurons. At neurite branch points,
the microtubules of the proximal segment are divided between the distal
segments without the addition of microtubules to the distal branches. Few
microtubules ends were seen in the cytoskeletons, and on occasion, the same
number of microtubules was counted at widely separated points along a
neurite segment. I conclude that microtubules are long in embryonal
neurites, and some may extend the entire length from perikaryon to neurite
tip. This may limit where microtubule growth occurs to the perikaryon and
the neurite tip, where many microtubule ends are. In addition, the great
length of most neuritic microtubules may explain why collateral sprouting
is rare along embryonal neurites.