Figure 6

Decreased GSK3β activity leads to increased microtubule dynamics in the growth cone. (A) Quantification of microtubule growth speed in naïve DRG neurons from WT or GSK3β(+/-) mice transfected with EB3-GFP; (n = 61 to 107 microtubules). (B) Quantification of EB3-fluorescence intensity relative to the distance to the tip of the growth cone, in naïve DRG neurons from WT or GSK3β(+/-) mice transfected with EB3-GFP; (n = 10 growth cones). For distances between 0.80 to 1.12, 2.64 to 3.04, 4.64 to 7.04 μm the differences shown are statistically significant with P <0.05. (C) Representative images of growth cones of naïve DRG neurons from WT or GSK3β(+/-) mice transfected with EB3-GFP. The green line surrounds the leading edge of the cell. Scale bar: 4 μm. (D) Quantification of the intensity ratios between acetylated and tyrosinated microtubules in WT or GSK3β(+/-) growth cones; (n = 101 growth cones). (E) Representative images of growth cones of naïve DRG neurons from WT or GSK3β(+/-) mice immunostained with acetylated and tyrosinated α-tubulin. Scale bar: 5 μm. (F) Quantification of microtubule growth speed in naïve neurons from cre⁺GSK3βwt/wt mice or cre⁺GSK3βlox/lox mice transfected with EB3-mCherry (n = 117 to 134 microtubules). (G) Quantification of the intensity ratios between acetylated and tyrosinated microtubules in cre⁺GSK3βwt/wt or cre⁺GSK3βlox/lox growth cones; (n = 102 to 105 growth cones). (H) Representative images of growth cones from cre⁺GSK3βwt/wt or cre⁺GSK3βlox/lox mice immunostained for acetylated and tyrosinated α-tubulin. Scale bar: 5 μm. All error bars are SEM. ***P <0.001. Two-tailed Student’s t test. DRG, dorsal root ganglia; GFP, green fluorescent protein; GSK3β, glycogen synthase kinase 3β; SEM, standard error of the mean. WT, wild type.