Inhibition of mature spine formation by PSD-Zip70C in vivo. A, B, GFP fluorescence images of neurons expressing GFP alone (A) or GFP and PSD-Zip70C (B). C, Quantitative analysis of the length of dendritic protrusions from neurons expressing GFP alone or GFP and PSD-Zip70C (each sample was quantified with 500 spines; n = 4 experiments). Mean ± SD; *p < 0.05 compared with GFP alone (Student's t test). Scale bars: A, bottom, 2 μm; A, middle, 20 μm; A, top, 200 μm. d, Dorsal, v, ventral.