Fig. 3. hGfap-cre^+/–;Pten^loxp/loxp mice show defects in granule neuron migration in vivo. (A) Granule cell migration was analyzed by BrdU pulse labeling. Mice were injected 100 mg/kg BrdU peritoneally and distribution of BrdU-labeled neurons was determined at 20 hours and 110 hours after injection. At 110 hours post-BrdU labeling, increased number of granule cells was seen in the ML of PTEN mutant mice (A, b') compared with littermate controls (A, a'). A histogram (quantitation of BrdU-labeled neurons within the ML) indicates that Pten mutant mice had a significant increase in cell number at 110 hours post-BrdU injection (P<0.001). (B) Ki67 and phospho-histone H3 immunostaining indicated that the proliferation zone in the EGL was largely maintained with no apparent ectopic proliferation within the ML. EGL, external granule layer; ML, molecular layer; PL, Purkinje cell layer; IGL, internal granule layer; WM, white matter. Scale bar: 50 µm.