PN-1 -/- mice show increased BrdU incorporation in the dentate gyrus. (A) BrdU-positive cells in dentate gyrus sections of WT and mutant mice without and with 12 days of running wheel exercise. (B) Number of BrdU-positive cells in WT and PN-1 -/- mice without and after running. All data are the means of 4 animals/condition/genotype, *P < 0.05, **P < 0.01. Scale bar: A 100 μm. (C) Scheme illustrating the timeline of the running injection protocol. WT and PN 1-/- mice kept without and with running wheel, were injected with BrdU daily for 12 days. BrdU analysis was performed either one day after the last BrdU injection or 4 weeks later. BrdU A: BrdU analysis.