Figure 2. Increase in the number of interneurons in Olig1−/− cerebellum and olfactory bulb.

(a) Low magnification imagea of MBP (green) and DAPI (blue) of juvenile cerebellum. The box represents the region where the images in b–d were taken. (b) Image taken of P21 cerebellum showing Pax2+ INs (red) and anatomy of cerebellar lobules with white matter defined by dense MBP immunoreactivity (green) and the granule layer defined by dense DAPI staining (blue). Note the ectopic presence of Pax2+ INs in the white matter (arrows) in the Olig1−/− mice. (c) Single channel image of Pax2 (red) staining in panel a demonstrating increased numbers of Pax2+ INs in Olig1−/− mice. (d) Representative images of immunohistochemistry showing increased numbers of cerebellar IN precursor cells expressing AP-2ß in Olig1−/− versus WT mice at P7. (e) Quantification of Pax2+ cells in the P21 cererbellum demonstrating a statistically significant increase in Pax2+ cells Olig1−/− versus WT mice. (f) Low magnification image of the olfactory bulbs of WT (f) vs Olig1−/− (f’) mice injected with BrdU at P2 stained for BrdU (red) and DAPI (blue). (g) Higher magnification images of the granule cell layer corresponding to the box inset labeled (g & g’) in panel (f). (h) Higher magnification images of the glomerular layer corresponding to the box inset labeled (h & h’) in panel (f). (i–j) Quantification of the number of BrdU+ cells in the P50 granule cell layer (GRL) and glomerular layer (GL) respectively, following BrdU injection at P2 demonstrating a statistically significant increase in BrdU+ cells in Olig1−/− versus WT mice. (c’) scale bar = 50 µm, (f) scale bar = 500 µm, (g) scale bar = 50 µm. (For all quantifications: mean +/− SEM, n = 3; *p<.05, **p<.01, 2 tailed unpaired student’s t test. Abbreviation: GRL = Granule layer, GL = Glomerular layer. See also Figure S1.