Figure 8. Sox2 is expressed in most postnatal pons OLPs.

(a–e) CD1 wild-type mice received BrdU 100 min before perfusion. (b) Representative P4 Sox2⁺Olig2⁺BrdU⁺ cell. Scale bar, 10 μm. (c) Representative P16 Sox2⁻Olig2⁺BrdU⁺ cell. Scale bar, 10 μm. (d) Breakdown of basis pontis BrdU⁺ cell density by Sox2/Olig2 co-staining, through postnatal development; mean±s.e.m., n=3 mice per timepoint. Sox2⁺Olig2⁺BrdU⁺ cells outnumber any other cell type (F_1,40≥196.91, P<0.0003, Bonferroni-adjusted two-way ANOVA based on cell type and age; tegmentum shown in Supplementary Fig. 7a). (e) P4 tissue from the indicated regions was analysed for the proportion, among total Olig2⁺BrdU⁺ cells, of Sox2⁺Olig2⁺BrdU⁺ triple-positive cells; n=3 mice, mean±s.e.m. Unpaired t-test confirmed Olig2⁺BrdU⁺ cells were more often Sox2⁺ in basis pontis than in ventral medulla (P=0.0055), dorsal medulla (P=0.0123), midbrain tegmentum (P=0.0152) or corpus callosum (P=0.0380), and more often Sox2⁺ in pontine tegmentum than ventral medulla (P=0.0231) or midbrain tegmentum (P=0.0366). *P<0.05 versus basis pontis; **P<0.01 versus basis pontis; ^†P<0.05 versus pontine tegmentum. (f–h) ALDH1L1:GFP mice received BrdU 100 min before perfusion. (g) Sox2⁺Olig2⁺BrdU⁺ALDH1L1:GFP⁻ cells (pink arrows) and Sox2⁺ALDH1L1:GFP⁺BrdU⁺Olig2⁻ cells (blue arrow) in P4 basis pontis. Scale bar, 20 μm. (h) BrdU⁺ALDH1L1:GFP⁺Olig2⁺ (white arrow) and BrdU⁺ALDH1L1:GFP⁺Olig2⁻ (blue arrow) subtypes of proliferative astrocytes in P0 tegmentum. Scale bar, 10 μm. (i) Densities of GFP⁺Olig2⁺BrdU⁺ cells in ALDH1L1:GFP pons, and of Sox2⁺Olig2⁺BrdU⁺ cells in wild-type pons; mean±s.e.m., n=3 mice per strain per timepoint. (j,k) CD1 wild-type mice age P4 were given BrdU as in a, perfused with short postfix (100 min, 4 °C), cryosectioned, and co-stained as indicated. (j) Representative basis pontis OLP; scale bar, 10 μm. (k) PDGFRα was expressed in ∼80% of Sox2⁺Olig2⁺BrdU⁺ progenitors; n=3 mice, mean±s.e.m. (l–n) Sox2:GFP mice received BrdU 100 min before perfusion. (m) P4 pons tissue co-stained as indicated. Yellow arrows indicate representative BrdU⁺GFP⁺Sox10⁺ triple-positive cells. Scale bar, 15 μm. (n) Sox2:GFP pons regions aged P4 or P45 were analysed for the proportion, among proliferative OLPs (Sox10⁺BrdU⁺), of cells expressing Sox2:GFP; this percentage was greater in P4 basis pontis than tegmentum (P=0.0026, unpaired t-test); n=3 mice per timepoint, mean±s.e.m., **P<0.01.