Figure: Anterograde transport of neurofilaments.
Neurons were engineered to express green-fluorescent-protein-labeled neurofilament protein (GFP-NFH) so that neurofilaments could be microscopically visualized in living neurons. The figure shows selected images from a time lapse sequence showing a GFP-NFH-labeled NF moving anterogradely (the cell body is to the left, while the axon tip is to the right). The numbers next to each frame indicate time in seconds. At the start of sequence, a relatively large gap in the GFP-NFH fluorescence occupies most of the field. A NF moves into and through the gap over a period of 80 sec. The moving NF first appears at 405 sec, and advances steadily through the gap during the subsequent 75 sec. The arrowheads identify the back end of the neurofilament. A portion of the time lapse sequence is shown in the movie. For a full account, see Roy et al., 2000, Neurofilaments are Transported Rapidly but Intermittently in Axons: Implications for Slow Axonal Transport. J. Neurosci. 20: 6849-6861.
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