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Figure 2
Axonal vesicular fusion coincides with the onset of myelination
(A and B) tdTcntn1a profile of a myelinated (A) and a not-yet myelinated (B) reticulospinal axon. tdTcntn1a is excluded from myelinated regions along axons. SypHy average projections and corresponding kymographs of the axonal segments in panels below. Basal SypHy signal is decreased along sheaths, suggesting surface SypHy displacement by myelin. SypHy events are present in non-myelinated regions (asterisks), myelinated regions (arrows) and at the tdTcntn1a+/tdTcntn1a− border (arrowheads).
(C) Axonal, but not collateral, SypHy frequency in myelinated reticulospinal axons is greater than in unmyelinated axons (axonal, p = 0.001; collateral, p = 0.30; Mann-Whitney test; axonal rates, 19 unmyelinated axons from 19 animals and 75 myelinated axons from 68 animals).
Scale bars, 5 μm, 60 s (A and B). Graphs display median and interquartile range.
See also