Figure 2.

A subpopulation of NG2 ⁺ /EGFP ⁺ cells displays an immature neuronal phenotype in the SVZ. P8 coronal sections. (A and B) NG2⁺/EGFP⁺ cells (blue/green, respectively) in the SVZ are not labeled for the astroglial markers GFAP (A, red) or GLAST (B, red). (C) A large percentage of the NG2⁺/EGFP⁺ cells (blue/green, respectively) in the SVZ are labeled with anti-Dlx antibodies (red) for neuronal progenitor cells. (D) A significant percentage of the NG2⁺/EGFP⁺ cells (blue/green, respectively) in the SVZ express the early neuronal markers PSA-NCAM (D, red) and βIII- tubulin (E, TUJ1; red). (F) The majority of the EGFP⁺/TUJ1⁺ cells (green/blue, respectively) are Dlx⁺ (red). Arrows indicate double-labeled NG2⁺/EGFP⁺ cells. NG2⁺/EGFP⁺ cells in boxed areas are shown at higher magnification. Bar, 50 μm. (G) NG2⁺/EGFP⁺ cells in the lateral ventricle of the SVZ. Virtually all NG2⁺/EGFP⁺ cells expressed Olig2 at P8 and P40, and EGFRs at P8. At P40 the percentage of EGFR⁺/NG2⁺ cells decreases by 50%. A similar decrease is also observed for Lex, Dlx, PSA-NCAM, and TUJ1. None of the NG2⁺/EGFP⁺ cells are labeled with anti-GFAP or anti-GLAST antibodies. (inset) Percentage of NG2⁺/EGFP⁺ cells that incorporated BrdU after 2 h of pulse labeling. No significant differences are detected between P8 and P40. This result was also confirmed by anti-Ki67 immunostaining. Percentages were obtained by counting NG2⁺/EGFP⁺ cells located into the SVZ region. Data are means ± SEM (total NG2⁺/EGFP⁺ cells counted equals 850 at P8 and 400 at P40; for each age, four to six brain sections from four different brains were used).