Overexpression of PSD-95 decreases branching even in the presence of a nonbinding mutant of EB3. A, Representative inverted GFP images of hippocampal neurons transfected with the indicated cDNA constructs. Neurons were transfected on DIV 7 and analyzed for dendrite number at DIV 12. Scale bars: 50 μm. B, Sholl analysis of neurons transfected with cDNA constructs for the indicated proteins. Analysis of neurons represented in A shows that overexpression of EB3-THR-GFP results in decreased dendritic complexity when compared to dendrite numbers of control neurons expressing GFP or neurons expressing EB3-GFP. ***p < 0.01 by two-way repeated measures ANOVA followed by a Bonferroni multiple comparisons test to compare each point on the curve. n = 24 neurons for each condition. C, Sholl analysis of neurons expressing EB3-GFP or EB3-THR-GFP alone or with PSD-95-mRFP. Neurons expressing EB3-THR-GFP show a decreased dendritic complexity when compared to control neurons. Expression of PSD-95-mRFP decreases dendrite number. Coexpression of either EB3-GFP or EB3-THR-GFP with PSD-95-mRFP results in a decrease in dendritic complexity that is equal to the decrease mediated by PSD-95 alone. ***p < 0.01 by two-way RM ANOVA followed by a Bonferroni multiple comparisons test to compare each point on the curve. n = 24 neurons for each condition. Error bars indicate SEM.