NeuroD2 regulates expression of PSD95 and SAP102 in the developing hippocampus. (A) Representative immunoblots against PSD95 and SAP102 in hippocampal lysates from WT and NeuroD2 null littermates at P14 and P21. Loading control is immunoblotting for β-tubulin. (B) Quantification of SAP102 relative expression (n = 3 littermate pairs). (C) Quantification of PSD95 relative expression as in (B) (n = 3 littermate pairs). (D) Quantitative PCR analysis of NeuroD2 and PSD95 mRNA expression in WT and NeuroD2 null cultures (n = 5 and n = 6, respectively). (E) LY filled, shVector-infected CA3 neuron. (F) LY filled, shPSD95-infected CA3 neuron. (G) Immunoblot for mCherry-tagged PSD95, co-transfected with PSD95 shRNA expressing lentiviral vector or control vector into 293T cells for 48 hours (duplicate experiment). Control is blotting with anti-GAPDH. (H) Quantification of TE spine head density between conditions (shVector, n = 9; shPSD95, n = 8). (I) Immunoblot for endogenous PSD95 in neuronal culture infected with a lentivirus expressing a second shPSD95 construct. (J) Quantification of TE spine head density with an independent construct, shPSD95-2 (control, n = 12; shPSD95-2, n = 15). *P < 0.05, **P < 0.01. Scale bar: 5 μm. Error bars represent ± standard error of the mean. KO, knockout.