Fig. 7. Plp-expressing cells in the OB express the AN2/NG2 marker of oligodendrocyte precursors. Coronal cryosections of E17.5 plp-sh ble-lacZ OB were double labeled with bluo-gal (A) or X-gal (B) and AN2 polyclonal antibody revealed with peroxidase-conjugated secondary antibody and DAB substrate. (A) Double-labeled ß-gal⁺/AN2⁺ cells, some of which (in the upper right corner) have the typical bipolar morphology of oligodendrocyte precursor. (B) In the subventricular layer (the limit of the ventricle (V) is indicated by a broken line), ß-gal⁺/AN2^– cells (arrows) are Plp⁺ cells, which are probably less advanced in the oligodendrocyte lineage than ß-gal⁺/AN2⁺ cells. Note that AN2⁺ endothelial cells (with a brown precipitate diffusely distributed in the cell body, arrowheads) are ß-gal negative. Scale bar: 13 µm.