Figure 1. OTX2 knockdown in the choroid plexus reduces newborn neurons in the olfactory bulb. A–C, Conditional Otx2 knockdown with Otx2lox/lox mice. A, Staining for OTX2 in lateral ventricle choroid plexus 35 d after intracerebroventricular injection of vehicle or Cre-Tat. B, Comparison of Otx2 expression levels between fourth and lateral ventricles from the same brain (linked data points represent individual mouse) after vehicle or Cre-Tat intracerebroventricular injection. Dotted line represents 30% decrease in Otx2 expression. C, Quantitative PCR analysis of Otx2 expression in fourth ventricle (****p < 0.0001, Mann–Whitney test, 5 experiments). D, Schematic of adult (3 months old) neurogenesis study paradigm. E, Staining for BrdU in a coronal section of olfactory bulb 3 weeks after BrdU injections. F, Quantification of BrdU-positive cells in GCL and GL of the olfactory bulb (**p < 0.01, ns = p > 0.05, t test, 3 experiments). G, Staining for caspase and DCX in a sagittal section of the RMS. Arrows indicate caspase-labeled neuroblasts throughout the entire RMS. H, Quantification of caspase/DCX colabeled cells in RMS (ns = p > 0.05, t test, 3 experiments). I, Schematic of adult V-SVZ proliferation study paradigm. J, Staining for BrdU in a coronal section of the V-SVZ 2 h after BrdU injection. K, Quantification of BrdU-positive cells in V-SVZ (ns = p > 0.05, t test, 2 experiments). L, Schematic of adult migration study paradigm. M, Staining for BrdU and DCX in a coronal section of the RMS. N, Quantification of BrdU/DCX colabeled cells in RMS (*p < 0.05, t test, 2 experiments). IP, Intraperitoneal; icv, intracerebroventricular; inj, injection; veh, vehicle. Error bars represent SD.