Figure 3.

Presynaptic accumulation of β-catenin requires local translation. A, Experimental design. B, Representative images of PDL-coated beads coimmunolabeled for β-catenin (magenta) and Bassoon (orange) within the axonal compartment in vehicle and CHX conditions. C, Quantification showing β-catenin/Bassoon intensity ratios within beads ROIs for vehicle (n = 472) and CHX (n = 548) conditions within the axonal compartment. Mean Bassoon fluorescence intensity for vehicle (veh, n = 701) and CHX (n = 805). D, Average mean pixel value surrounding bead (vehicle, n = 121; CHX, n = 84) compared with off-bead (vehicle, n = 104; CHX, n = 67). E, β-Catenin/Bassoon intensity fraction with control and β-catenin siRNA applied to the axonal compartment. Average pixel value of each frame (2 chambers, 10 frames per chamber) was used from both the axonal and somatic compartments. *p < 0.01. All values are normalized to average intensity for vehicle condition. F–H, β-Catenin and Bassoon fluorescence intensity around beads compared in the presence or absence of somata and CHX. G, Somata were removed and CHX was immediately applied to the axon terminals; the remaining events progressed as depicted in the timeline shown in A. Scale bar, 5 μm. H, Bar chart showing average fluorescence of β-catenin relative to Bassoon, β-catenin alone, and Bassoon alone within each bead ROI, for vehicle (n = 288), cells removed with vehicle added to axonal compartment (n = 366), and cells removed with CHX added to axonal compartment (n = 267). *p < 0.05. Error bars, SEM.