In addition to neuronal recombination, recombination in nonneuronal cells was evident among astrocytes in midbrain and neocortex ( Figure S3), oligodendrocytes in corpus callosum ( Figure S3) and Bergmann glial cells in

cerebellum (data not shown). No animals exhibited gross congenital defects or tumors in the brain. PTEN KO granule cells exhibited numerous morphological abnormalities characteristic of granule cells from rodents with temporal Onalespib datasheet lobe epilepsy ( Parent et al., 2006; Jessberger et al., 2007; Walter et al., 2007; Kron et al., 2010; Murphy et al., 2011, 2012; Pierce et al., 2011), including neuronal hypertrophy, de novo appearance of basal dendrites, increased dendritic spine density, and ectopically located somata. For illustrative purposes, a small number of PTEN KO animals were crossed into the Thy1-GFP expressing mouse line ( Feng et al., 2000; Vuksic et al., 2008; Danzer et al., 2010), which labels a subset of granule cells with GFP regardless of PTEN expression. GFP expression within adjacent wild-type and PTEN KO cells in these animals revealed

the dramatic morphological impact of PTEN deletion ( Figures 2A and 2B). Quantification of these changes in PTEN KO animals crossed to GFP reporter mice revealed increases in mean soma area from 59.3 ± 3.5 μm2 in control animals to 176.2 ± EPZ-6438 12.1 μm2 in PTEN KO animals (p < 0.001, t test; control n = 4 mice [40 cells]; PTEN KO n = 5 mice [36 cells]).

The percentage of GFP-expressing granule cells ectopically located in the hilus ( Figure 2F) increased from 0.3% ± 0.3% in controls to 3.3% ± below 1.0% in PTEN KO mice (p = 0.049, t test; control n = 5 mice [519 cells examined]; PTEN KO n = 8 mice [1,544 cells]). The number of apical dendrites increased from 1 [range 1.0–1.1] in control mice to 1.8 [1.4–2.3] in PTEN KO mice (p = 0.016, Mann-Whitney rank sum test [RST]; control n = 4 [40 cells], PTEN KO n = 5 mice [36 cells]). Spine density along these dendrites more than doubled ( Figures 2C and 2D), increasing from 2.9 ± 0.4 spines/μm to 7.5 ± 0.5 spines/μm (control, n = 4 mice [12 cells]; PTEN KO, n = 4 mice [12 cells], p < 0.001, t test). The number of basal dendrites/cell increased from an animal median of 0 [range 0–0] in controls to 0.8 [0.4–1.0] in PTEN KO mice ( Figure 3; p = 0.016, RST; control n = 4 mice [40 cells]; PTEN KO n = 5 mice [36 cells]). Basal dendrites, normally lacking in control rodents, are common in several models of temporal lobe epilepsy. 58.1% ± 6.9% (12 dendrites from three mice) of dendritic spines coating these hilar basal dendrites were apposed to puncta immunoreactive for zinc transporter-3 ( Figure 3). Zinc transporter-3 (ZnT-3) labels granule cell mossy fiber terminals ( McAuliffe et al., 2011), and the apposition of presynaptic and postsynaptic components implies that PTEN KO cells receive recurrent excitatory input from neighboring granule cells.