Figure 1.

Effects of BDNF deletion in adult-born GCs on dendrite development. A, Schematic diagram showing the experimental procedure for labeling newborn GCs in adult mice through retrovirus-mediated gene transfection. Mice were perfused at different time points as indicated. mpi, Months postinfection. Sample confocal projection images (right) from newborn GCs (GFP ⁺) in the hippocampus at 8 wpi. Blue: DAPI staining; green: GFP. Scale bar, 300 μm. B, Example images of newborn neurons expressing Cre recombinase and GFP at 2 wpi, 8 wpi and 3 mpi in WT (left) and BDNF^f/f mice (right). Scale bar, 50 μm. C–D, Histograms showing total dendrite length and total branch number of WT (WT + Cre) and BDNF^f/f (BDNF^f/f + Cre) mice at each time point (mean ± SEM; n = 25–108 for each time point; 3–4 mice per point; ***p < 0.001, one-way ANOVA followed by Student's t test). E, Representative confocal image of adult-born GCs in the same slice from mice coinjected with retrovirus expressing Cre and GFP and retrovirus expressing only mCherry at 2 wpi. Magenta: normal newborn neuron expressing mCherry only; green: BDNF deleted neurons expressing both Cre and GFP; blue: DAPI staining. F, Graph depicts results of dendrite morphology analysis for all dendrites examined for neurons similar to those depicted in D (mean ± SEM; n = 16–30 neurons for each group; 3 mice each; ***p < 0.001, one-way ANOVA followed by Student's t test). G, Immunostaining of newborn GCs for Cre and GFP in adult DG from WT and BDNF^f/f mice. Red: Cre; green: GFP; blue: DAPI. H, Schematic diagram of the experimental procedure (top). Representative confocal images of newborn GCs in adult BDNF^f/f/Nestin-CreER^T2/Rosa26-YFP mice through TAM induction and retrovirus-mediated gene transfection (bottom). I, Histograms showing total dendrite length and number of branch points for control and BDNF KO GCs similar to those depicted in G (mean ± SEM; n = 20–25 neurons for each group; 3 mice each; ***p < 0.001, one-way ANOVA followed by Student's t test).