Fig. 5.

Effects of MEF2C on excitatory synapse number in dentate granule neurons. Spine density of dentate gyrus dendrites was determined from Golgi-stained sections of (A) Mef2c^+/+, Mef2c^BKO/KO and MEF2C-VP6 Tg mice. (Scale bar, 10 μm.) (B) Mef2c^BKO/KO animals have a significant increase in spine density when compared to WT littermates. *, Statistical significance in pairwise comparison; P = 0.0001. MEF2C-VP16 transgenic mice show a decrease in spine density when compared to WT littermates. **, Statistical significance in pairwise comparison; P = 0.018. For Mef2c^BKO/KO mice; P = 0.0001 using two-tailed two-sample equal variance t test; n = 30 dendritic segments from 26 neurons of two mice and n = 27 dendritic segments from 25 neurons of two mice, respectively. For MEF2C-VP16 transgenic mice; P = 0.018 using two-tailed two-sample equal variance t test; n = 28 dendritic segments from 26 neurons of two mice and n = 25 dendritic segments from 23 neurons of two mice, respectively. (C) Average density of synapsin-1-PSD-95 coclusters along the dendrites of cultured hippocampal neurons. There was no significant difference in the number of excitatory synapses between Mef2c^BKO/KO and WT neurons.