Overexpression of truncated SHANK3 variants results in distinct alterations of dendritic spines and synaptic contacts. Evaluation of dendritic spines (A-C) and synaptic contacts (D-F) in rat primary hippocampal neurons co-transfected with DenMark and either empty vector-based GFP (Control), full-length GFP-Myc-SHANK3 (SHANK3), or truncated GFP-Myc-SHANK3 variants (G1527A, 2497delG, A5008T) (DIV11-14). (A) Representative images of the DenMark signal in secondary dendrites of rat primary hippocampal neurons overexpressing either Control, SHANK3, G1527A, 2497delG, or A5008T as indicated. (B) Quantitative analysis of spine density. (C) Quantitative analysis of filopodia density. (D) Representative images of VGLUT1-positive (upper two rows) and VGAT-positive (lower two rows) presynaptic specializations among secondary dendrites of rat primary hippocampal neurons overexpressing either Control, SHANK3, G1527A, 2497delG, or A5008T, as indicated. (E) Quantitative analysis of VGLUT1-positive puncta density. (F) Quantitative analysis of VGAT-positive puncta density. White bars, Control; black bars, SHANK3; red bars, G1527A; green bars, 2497delG; and blue bars, A5008T. *P < 0.05 and ***P < 0.001 compared with Control; oo
P < 0.01 and ooo
P < 0.001 compared with SHANK3.