FIGURE 1.

Purkinje cell axonal torpedoes peak at P11 during postnatal mouse development. (A) Sample images highlighting Purkinje cell axons at P7 (left), P11 (middle), and P30 (right) from L7-tau-GFP mice. White arrows point to torpedoes. Note the abundance of Purkinje cell axon torpedoes at P11. Scale bar, 20 μm. (B) Summary data showing number of torpedoes peak at P11, with nearly 40% of Purkinje cell soma with a torpedo. Torpedoes are nearly absent during first week (P5-7) of development. Even at P30, there are a significant number of Purkinje cells that harbor axon torpedoes. (C) Left, illustration of how cell density measurements were taken. The number of Purkinje cells per length of lobule were counted for the entire Lobule III to calculate total Purkinje cell density, cell count/length. Right, sample image of sagittal slice through lobule III. Note that there are torpedoes present in the white matter that have not been included in our analysis. Scale bar, 100 μm. (D) Purkinje cell density (cells/mm lobule) in Lobule III is higher at P5 and P7, but remains constant after P9, consistent with reports that apoptosis is over by P9 in developing mouse Purkinje cells (Jankowski et al., 2009). (E) Torpedoes were also transiently enriched in P11 C57BL6/J wild-type (WT) cerebellum, and were low at both P7 and P30. Significance determined by Wilcoxon multiple comparisons followed by Benjamini–Hochberg procedure with the FDR of 0.05 for panel (B,E); significance determined by one-way ANOVA followed by Tukey HSD test for panel (D). Asterisks denote the minimum significance for comparisons where the letter denotes the relevant comparisons: a = significantly different from P9, P11, P13, P15, and P30; b = significantly different from P5 and P7; c = significantly different from P11; d = significantly different from P9; e = significantly different from P5, P7, P13, P15, and P30. All comparisons that are non-indicated are not significantly different, P > 0.05. ^∗P < 0.05; ^∗∗P < 0.01; ^∗∗∗P < 0.005.