Figure 7

The spatial distribution of microtubule polymerization becomes biased towards distal regions as axons and dendrites develop. (A, B) The mean number of comets per micron was determined within segments representing the proximal-middle versus distal region (excluding the growth cone) of axons (A) and dendrites (B). For both axons and dendrites, microtubule polymerization was distributed equally within all regions at the earliest stages of development, but predominated within distal segment as neurons matured. Error bars represent standard error of the mean; P < 0.0001.