Figure 2: Proximal thinning prevents protein diffusion.
From: Local endocytosis triggers dendritic thinning and pruning in Drosophila sensory neurons
(a) A schematic of the photoactivation experiment. The cell body of C4da neurons expressing PA-TagRFP is photoactivated with ultraviolet laser, just after they commence compartmentalized Ca2+ transients. Distal diffusion of photoactivated PA-TagRFP is monitored after the photoactivation. (b) Representative images of a C4da neuron expressing GCaMP6s. Top, basal fluorescence of GCaMP6s in a C4da neuron. Bottom, a ratiometric image of GCaMP6s fluorescence showing the robust Ca2+ influx into a branch unit. Both images are taken just before photoactivation. Green open arrowheads indicate the proximal edge of the branch unit. Scale bar, 20 μm. (c) Representative images showing distal diffusion of photoactivated PA-TagRFP. Time stamps are seconds after the photoactivation. The regions for quantitative analysis in d are shown in the middle panel. Arrows indicate the diffusion of PA-TagRFP into non-branch unit. Sixteen animals in total were examined. (d) Time course of PA-TagRFP diffusion in the dendritic regions. Regions of interest are shown in c. An asterisk indicates artificial increase of the red fluorescence around the cell body after photoactivation.
