Figure 2

miR-137 regulates dendritic development and phenotypic maturation of new neurons in vivo. (A) A schematic diagram showing the retroviral vector used for in vivo miR-137 expression. miR-137 (sh-miR-137) or control miR (sh-Con) was expressed as a short hairpin under U6 RNA Polymerase III promoter while eGFP was expressed under a chicken β-actin (CAG) promoter. (B) Schematic diagram showing that control virus (sh-Con) was injected into the left hemisphere, and retrovirus expressing miR-137 (sh-miR-137) was injected into the right hemisphere. (C, D) Confocal z-stacks showing eGFP-expressing neurons at 4 weeks post-injection (4 wpi) with representative traces from both the sh-Con (C) and sh-miR-137 condition (D) (scale bar = 50 μm). (E) Neurons overexpressing sh-miR-137 show reduced dendritic complexity compared with controls, as determined by Scholl analysis. (F–H) Neurons overexpressing sh-miR-137 show reduced dendritic length (F), number of nodes (branch points, G), and dendritic ends (H). (I) Neurons overexpressing sh-miR-137 show reduced dendritic spine density. (J) Confocal z-stacks showing eGFP-expressing dendrites (scale bar = 20 μm). (K) A representative dendritic segment used for spine density analysis (* = p < 0.05)