a specific shRNA against mouse nkcc1 (shRNA-NK1) abolishes GABA-induced depolarization of newborn neurons in the adult hippocampus (Ge et al., 2006). Consistent with a critical role of depolarizing GABA signaling in adult neurogenesis, shRNA-NK1+/GFP+ new neurons exhibited significant decreases in total dendritic length and complexity at 14 dpi (Figures 1A, 1B and S1D). There was no apparent effect of shRNA-NK1 expression on soma size, number of primary dendrites and positioning of new neurons at all time points examined (Figures S1A to S1C). Notably, the major effect of depolarizing GABA signaling and DISC1 KD on dendritic growth of new neurons exhibited a similar time-course, but in the opposite direction (Figure 1B).
