Fig. 7.

Phenotype of ARPP21 loss- and gain-of-function during cortical neuron differentiation in vivo. a IUE at E15.5 with Arpp21 shRNA or overexpression constructs followed by morphological analysis at P14. b qRT-PCR of endogenous Arpp21 mRNA levels in N2A cells confirms efficacy of Arpp21 shRNA knockdown using Oaz1 mRNA as standard. ***p < 0.001, Student’s t-test, n = 3. Data represent mean ± s.d. c Representative reconstructions of a neuron expressing a non-targeting control shRNA (shNeg) and an ARPP21 knockdown (shArpp21) neuron. Scale bar: 50 µm. d Sholl analysis of control (shNeg; black) and ARPP21 knockdown (shArpp21; turquoise)-expressing neurons shows significantly decreased dendritic complexity upon ARPP21 knockdown. e Reconstructions of representative neurons expressing either GFP or ARPP21 under control of the NeuroD1 (ND1) promoter (plasmids ND1::IRES-GFP or ND1::ARPP21-IRES-GFP, respectively). f Sholl analysis reveals a significantly increased dendritic complexity of ARPP21-overexpressing (ND1::Arpp21; turquoise) neurons compared to control neurons (ND1::GFP; black). *p < 0.05, **p < 0.01, ***p < 0.001, two-way ANOVA with Bonferroni post-test. shNeg: n = 14 cells. shArpp21: n = 11 cells. ND1-GFP: n = 20 cells. ND1-Arpp21: n = 14 cells. Data expressed as mean ± s.e.m. Scale bar: 50 µm