Fig. 1: Ptbp2 modulates axon growth in cultured motoneurons.

a Ptbp2 mRNA expression detected by qPCR in the spinal cord of mice at different time points. Nefl mRNA was used for normalization. One-way ANOVA with Dunnett’s multiple comparisons test. Data are mean ± standard deviation (s.d.) of n = 3 biological replicates. b Immunoblot analysis of Ptbp2 in control and Ptbp2-depleted motoneurons at DIV 6. Histone H3 was used as a loading control. c Quantitative analysis of Ptbp2 immunoblots as shown in (b). Two-tailed one-sample t test. Data are mean ± s.d. of n = 4 (sh1Ptbp2) and n = 3 (sh2Ptbp2) biological replicates. d Quantification of motoneuron survival at DIV 6. Two-way ANOVA with Sidak’s multiple comparisons tests. ns, not significant (P > 0.05). Data are mean ± s.d. of n = 3 biological replicates. e Representative images of motoneurons transduced with a control lentivirus (Ctrl), a lentivirus expressing a shRNA targeting Ptbp2 (sh1Ptbp2) and rescued motoneurons transduced with a lentivirus co-expressing sh1Ptbp2 and knockdown-resistant EGFP-Ptbp2 (sh1Ptbp2 + EGFP-Ptbp2) at DIV 6. Motoneurons were stained against tau as a specific axonal marker. Scale bar, 10 µm. f SuperPlots representing the quantification of axon lengths. One-way ANOVA with Tukey’s multiple comparisons test or unpaired two-tailed Student’s t test. Data are mean ± s.d. of n = 3 biological replicates. Representative images (g) and SuperPlots (h) of growth cone sizes of control, Ptbp2 knockdown and rescued motoneurons at DIV 6. Motoneurons were stained with phalloidin. Scale bar, 5 µm. One-way ANOVA with Tukey’s multiple comparisons test or unpaired two-tailed Student’s t test. Data are mean ± s.d. of n = 3 biological replicates. i Synapsin1 immunostaining in growth cones of control and Ptbp2-depleted motoneurons at DIV 6. Scale bar, 5 µm. j SuperPlots of Synapsin1 immunosignals in growth cones. Unpaired two-tailed Student’s t test. Data are mean ± s.d. of n = 3 biological replicates. k Immunofluorescence imaging of Piccolo in growth cones of control and Ptbp2 knockdown motoneurons. l SuperPlots of Piccolo immunosignals in growth cones. Unpaired two-tailed Student’s t test. Data are mean ± s.d. of n = 3 biological replicates. Source data are provided as a Source Data file.