Fig. 1.

CDKL5 expression during differentiation in neuroblastoma cell lines.

A: Immunofluorescence images showing the morphology of SH-SY5Y (upper panel) and SKNBE (lower panel) cells after 7 days of treatment with (+RA) or without (− RA) retinoic acid. Cells were stained for β-tubulin III (green) and nuclei were counterstained with Hoechst dye (blue). Scale bar: 30 μm. B: Quantification of neurite outgrowth of SH-SY5Y (upper histogram) and SKNBE (lower histogram) cells that were either untreated or treated with RA (10 μM) for 3 and 7 days. Neurite outgrowth was expressed as mean neurite length (μm) per cell. Data are expressed as mean ± SE of 4 independent experiments. A minimum of 400 cells were evaluated in each experiment for each condition. *P < 0.05; ***P < 0.001, treated vs. untreated condition (Bonferroni's test after ANOVA). C: Quantification by RT-qPCR of CDKL5 expression in SH-SY5Y and SKNBE cells that were either untreated or treated with RA (10 μM) for 3 and 7 days. Data, given as percentage of untreated SH-SY5Y cells, are expressed as mean ± SE. The asterisks indicate a significant difference between treated vs. untreated condition, *P < 0.05, ***P < 0.001 (Bonferroni's test after ANOVA). D: CDKL5 protein expression in SH-SY5Y cells either untreated or treated with RA (10 μM) for 3 and 7 days was analyzed by immunoblot with a CDKL5 specific antibody.