Figure 2. Neuropathological abnormalities.

A. Cenpj^tm/tm mouse brain weights were two standard deviations below that of control mice (n = 144 baseline control mice). *P = 0.0002, t-test, Cenpj^tm/tm, n = 6 and Cenpj ^+/+ n = 10. The lower whisker extends to the lowest datum still within 1.5 Inter-quartile range (IQR) of the lower quartile. The upper whisker extends to the highest datum still within 1.5 IQR of the upper quartile B. The dentate gyrus was significantly shorter in Cenpj^tm/tm mice (n = 3) when compared to Cenpj ^+/+ control mice (n = 30), *P = 0.01, t-test. Scale bar 1 mm C. Social recognition test. When tested for habituation-dishabituation, both Cenpj^tm/tm (n = 7) and Cenpj ^+/+ (n = 7) mice recognized a novel stimulus mouse as shown by a decline in investigation time over the first four trials that was recovered on trial five, when they were exposed to a novel mouse (trial four vs. trial five, * P = 0.0033 and ** P = 0.0014, two-way ANOVA followed by post-hoc t-test). D. A discrimination test was performed 24 h later the habituation-dishabituation test. When given a choice between the familiar (same stimulus animal used for trials one to four) and a new unfamiliar mouse 24 h later, Cenpj^tm/tm mice could not discriminate as shown by the similar investigation time for both stimulus animals (Cenpj ^+/+ P = 0.0326, Cenpj^tm/tm P = 0.957, t-test). E. Representative images of immunohistochemical stainings of E14.5 embryo sections. Cenpj was highly expressed in areas of active neurogenesis within the telencephalon. Scale bar 400 µm. There was a generalized increase in cleaved (activated) caspase-3-positive (scale bar 100 µm) and Ser139-phosphorylated H2AX (γH2AX; scale bar 200 µm) cells throughout embryos, images of striatum are shown.. The number of cells positive (as a percentage of total in two different 75 µm² areas) for cleaved (activated) caspase-3 (C3A+) and pan-nuclear Ser139-phosphorylated H2AX (γH2AX) was increased in areas of active neurogenesis within the striatum and cortex. *P<0.05; Mann-Whitney with continuity correction, Cenpj^tm/tm n = 3 and Cenpj ^+/+ n = 3. Data shows mean and SEM. F. Neuron densities were counted in three different areas (75 µm²) of active neurogenesis for each of the striatum (STR), cortex (CTX) and pro-hippocampus (HIP) and three areas of 150 µm² in the mid-striatum (M-STR) of E14.5 embryos, *P = 0.0008, t-test, Cenpj^tm/tm n = 3 and Cenpj ^+/+ n = 3. Data shows mean and SEM.