Fig. 4.

Newly generated cells in the SEL of the HD brain exhibit either a neuronal or glial phenotype. (a) Confocal microscopy demonstrates that the SEL of the HD brain contains newly generated cells that coexpress PCNA and βIII-tubulin and stain with a Hoechst stain. The new neurons are located in the lower part of the SEL. (Scale bar, 6 μm.) (b–d) Higher magnification of the neuron, which is outlined with a box in a. (Scale bar, 3 μm.) (b) Hoechst (blue) stains the nucleus of cells in the SEL. (c) PCNA (red) labels the nucleus of a new cell and has a granular appearance (19). (d) βIII-tubulin (green) labels the cytoplasm of neurons early in their development. (e) The merged image demonstrates coexpression of PCNA and βIII-tubulin in the same cell that displays a Hoechst⁺ stain, indicating that neurogenesis occurs in the SEL of the HD brain. (f) Confocal microscopy demonstrates that the SEL of the HD brain also contains newly generated cells that coexpress PCNA and GFAP and stain with a Hoechst stain. These new glial cells are located in the upper part of the SEL in the HD brain. (Scale bar, 18 μm.) (g–i) Higher magnification of the glial cell, which is outlined with a box in f. (Scale bar, 9 μm.) (g) Hoechst (blue) stains the nucleus of cells in the SEL. (h) PCNA (red) labels the nucleus of the cell with punctate staining. (i) The astrocytic marker GFAP (green) labels the cytoplasm of the cell. (j) The merged image demonstrates coexpression of PCNA and GFAP in the same cell that displays a Hoechst stain, indicating the occurrence of gliogenesis. Images a–e and f–j were each obtained by using different excitation wavelengths, and the signal was detected at different emission wavelengths.