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. Author manuscript; available in PMC: 2017 Jul 20.
Published in final edited form as: Neuron. 2016 Jun 30;91(2):356–369. doi: 10.1016/j.neuron.2016.06.013

Figure 1. SRGAP2A and its human-specific paralog SRGAP2C regulate the maturation and the density of inhibitory synapses in vivo.

Figure 1

(A) Visualization of inhibitory synapses in sparse layer 2/3 cortical pyramidal neurons after in utero electroporation (IUE) with soluble TdTomato (red) and EGFP-Gephyrin (EGFP-GPHN, green). Inhibitory synapses in oblique apical dendrites (insets) are located in the dendritic shaft (large arrowheads) or directly in dendritic spines (small arrowheads). P69: postnatal day 69, shSrgap2: shRNA targeting mouse Srgap2a. Scale bars: 100 μm (top left), 10 μm (top right and bottom panels).

(B) Segments of dendrites from layer 2/3 pyramidal neurons expressing a control shRNA (shControl), shSrgap2 or SRGAP2C along with EGFP-Gephyrin in juvenile mice (P21). The dashed lines indicate the contour of dendrites (from TdTomato). Arrowheads point to examples of Gephyrin clusters in spines. Scale bar: 1 μm.

(C–H) Quantifications of Gephyrin cluster density (C, F), equivalent (Eq.) diameter (D, G), and proportion of Gephyrin clusters located in spines (E, H) in juveniles (C–E) and adult mice (F–H). Juveniles: nshControl = 32, nshSrgap2 = 36, nSRGAP2C = 31. Adults: nshControl = 21, nshSrgap2 = 23, nSRGAP2C = 22. Mean ± SEM in C, E, F, H. Box plot showing the distribution of the mean value per cell in D and G. *** p < 0.001, ** p < 0.01, NS (Not Significant): p > 0.05, Kruskal-Wallis test followed by Dunn’s Multiple comparison test. (I) Similar effects of SRGAP2C expression on the density of dendritic spines (red) and Gephyrin clusters (green) in adult cortical neurons (P>65). Norm. density: normalized density. Spines (data from Charrier et al., 2012): nControl = 14 and nSRGAP2C = 12. Gephyrin: same as in h. *** p < 0.001, NS: p > 0.05, Mann Whitney test. See also Figure S1 and S2.