Figure 6.

CaMKII activity is required for repulsive growth cone turning away from a gradient of Wnt5a. (A) At left, cortical growth cones responding to Wnt5a gradients in Dunn chambers over 2 h. Images have been oriented such that high-to-low concentration gradients of BSA (vehicle control) or Wnt5a are highest at the top of the images. (Top panel) Control growth cones in BSA continue straight trajectories. (Middle panels) Three different growth cones show marked repulsive turning in Wnt5a gradients. (Bottom panel) Transfection with CaMKIIN abolishes Wnt5a induced repulsion. Scale bars, 10 μm. (B) A graph of fluorescence intensity (Z axis) of a gradient of 40 kDa Texas Red dextran at different positions in the bridge region of the Dunn chamber. A high-to-low gradient (along the X axis) is formed from the edge of the bridge region facing the outer chamber containing Texas Red dextran (0 μm) to the edge facing the inner chamber lacking Texas Red dextran. This gradient persists for at least 2 h (Y axis). (C) Rates of outgrowth of control- or CaMKIIN-transfected axons in Dunn chambers treated with gradients of BSA or Wnt5a. (D) Cumulative distribution graph of turning angles of control- or CaMKIIN-transfected axons in Dunn chambers treated with gradients of BSA or Wnt5a. **p < 0.01, Wilcoxon signed rank test. (E) Graph of turning angles of control- or CaMKIIN-transfected axons in Dunn chambers treated with gradients of BSA or Wnt5a. **p < 0.01, ANOVA on Ranks with Dunn's posttest.