(A-H) DOCK7 knockdown impairs ChC cartridge/bouton development. (A-C) Representative images of ChCs in layer II/III of somatosensory cortex from mice co-electroporated at E12.5 with plasmids expressing EGFP and scr#1 shRNA, Dock7#2 shRNA, or Dock7#2 shRNA+Flag-DOCK7 (DOCK7), and sacrificed at P28. Enlarged view of ChC cartridges with boutons is depicted on bottom. Scale bars, 20 μm (top) and 5 μm (bottom). (D-F) Representative images illustrating innervation of AISs by cartridges of ChCs transfected with EGFP-expressing plasmid and one of the indicated constructs. The AIS is visualized by immunostaining with an antibody to pIkB. Scale bar, 10 μm. (G, H) Quantification of bouton density (G) and size (H). Data are means ± SEM; 7-11 ChCs from 3 animals were analyzed for each condition, and for each cell 7-15 cartridges (G) and 52-149 boutons (H) were analyzed. ***p < 0.001; ns (not significant) indicates p ≥ 0.05, as compared with scr#1; one-way ANOVA, post hoc Tukey-Kramer test.
(I, N) Ectopic DOCK7 expression promotes ChC cartridge/bouton development. (I, J) Representative images of ChCs in layer II/III of somatosensory cortex from mice co-electroporated at E12.5 with plasmids expressing EGFP and empty control vector (vector) or Flag-DOCK7 (DOCK7), and sacrificed at P28. Enlarged view of ChC cartridges with boutons is depicted on the bottom. Scale bars, 20 μm (top) and 5 μm (bottom). (K, L) Representative images illustrating innervation of AISs by cartridges of ChCs transfected with EGFP-expressing plasmid and one of the indicated constructs. Scale bar, 10 μm.
(M, N) Quantification of bouton density (M) and size (N). Data are means ± SEM; 11 ChCs from 3 animals were analyzed for each condition, and for each cell 7-17 cartridges (M) and 54-155 boutons (N) were analyzed. ***p < 0.001; Student's t-test.