Fig 8. The axonal diffusion barrier is in the first 20 microns of the ddaE neuron.

A. mCD8-GFP was expressed in the ddaE neuron, and examples of FRAP experiments are shown. For the proximal axon region the ddaD cell was not killed, but for the more distal regions the neighboring ddaD cell was killed so that signal from ddaE could be collected without interference from a bundled axon. The bleach area is indicated by the red circle, and the distances indicated are the distance from the start of the axon to the side of the bleach region closest to the cell body. B. The average recovery of fluorescence into the bleached area was plotted. The n for each group was: 15 for dendrite, 25 for axon 0–15 μm, 16 for axon 20–50 μm, 13 for axon 70–140 μm. The error bars show the standard error of the mean. C. The recovery plateau; the average values between 110 and 120 seconds, for each group are shown. *** p value <0.001 calculated with an unpaired t-test. Error bars show the standard deviation.