Figure 5.

Measuring autophagy substrate clearance in vivo. (a) Zebrafish were generated which express the fluorescent, photoconvertible protein Dendra tagged to human tau, a known autophagy substrate. The green fluorescent Dendra protein can be photoconverted to a red fluorescent protein by exposure to 405 nm light. (b) Mosaic expression of the transgene allows individual neurons in the spinal cord to be identified and selected for photoconversion. Images of the same neurons were taken before and immediately after photoconversion and then at 12 h intervals. The amount of red fluorescent signal was quantified at each time point and used to calculate the clearance of tau protein. (c) Schematic diagram of the clearance kinetics of tau in response to manipulation of autophagic flux. Treatment with autophagy inducers (green) accelerates the clearance of tau protein whereas treatment with autophagy blockers (red) slows the clearance kinetics.