Figure 5. CTIP2-positive neurons with 4C DNA content in the mouse cerebral cortex. A, Cell nuclei isolated from the cerebral cortex of 2-month-old mice immunostained with an anti-CTIP2-specific antibody (green) and counterstained with DAPI (blue). Arrow, A CTIP2-positive nucleus. B, Cell nuclei immunostained with the anti-CTIP2 antibody (α-CTIP2) or with the secondary antibody alone (Control) were PI stained and subjected to flow cytometric analysis. Right, Illustrates the threshold used for the discrimination of CTIP2-positive nuclei. C, DNA content (Propidium Iodide-A) plotted against CTIP2 signal intensity (FITC-A) demonstrates that most nuclei with 4C content are positive for CTIP2 immunolabeling. D, DNA content histogram from CTIP2-negative nuclei. E, DNA content histogram from CTIP2-positive nuclei. See Table 2 for quantitative data. F, Coronal cryosections (15 μm) obtained from cerebral cortex of E17.5 mouse embryos were immunostained with and anti-CTIP2 antibody (green) and labeled with DAPI (blue) for DNA quantification. G, DNA content histogram in CTIP2-positive nuclei obtained by SBC. H, Top, A high magnification of box shown in F. Arrow, Nucleus with 4C DNA amount. Bottom, CTIP2-positive nuclei were used for DNA quantification only in those cases in which DAPI signal was clearly identified as a single nucleus (numbered nuclei). I, J, CTIP2-positive cell nuclei from the cerebral cortex of 2-month-old mice, isolated by FACS, subjected to FISH with a chromosome 11-specific probe (red), and counterstained with DAPI (blue). Arrows, Hybridization spots. Scale bars: A, H, I, J, 10 μm; F, 40 μm.