Axonal vesicular fusion consolidates nascent myelin sheaths
(A and B) Examples of 3–4 dpf time-course analyses of myelination of control RS axons (GFP-2A-tdTcntn1a) and RS axons with blocked vesicular fusion (BoNTB-GFP-2A-tdTcntn1a).
(C) Nascent sheaths in axons with blocked vesicular fusion grow slower (p = 0.048, Mann-Whitney test, 19 control axons from 18 animals and 17 BoNTB axons from 15 animals).
(D) Proportion of axons with and without full sheath retractions (p = 0.038, Fisher’s exact test). Numbers in bars indicate absolute number of axons.
(E) Sheaths >6 μm have a non-significant slower median growth in BoNTB-silenced axons (p = 0.488, Mann-Whitney test, 13 control axons from 13 animals and 14 BoNTB axons from 13 animals).
(F) Proportion of sheaths at 4 dpf fully grown (flanked by nodes and/or collaterals) or still with space to grow (p = 0.001, Fisher’s exact test). Numbers in bars indicate absolute number of sheaths.
Scale bars, 5 μm (A and B). Graphs display median and interquartile range.
See also Figure S2.