Fig. 1

Sox9 is a Marker of Neural Progenitors. (a) Immuno-labeling of an E14.5 brain (parasagittal, rostral right, dorsal up) reveals Sox9+ (red) neural progenitors lining the ventricles. (b) E14.5 cortex immuno-labeled for Sox9 (red) and Tbr2 (green). (b a -b d) Sox9+ neural progenitors, Tbr2+ intermediate progenitors (IPs), DAPI stained cell nuclei, and merged views. (b e -b g) Higher magnification of ventricular zone/ subventricular zone region shows interspersed Sox9+ neural progenitors (red) and Tbr2+ IPs (green). Though predominantly non-overlapping, occasional Sox9+/ Tbr2+ co-labeling of cells was observed (arrowhead). (c) Sox9 ^CreER;Ai14 tamoxifen-inducible reporter mice were utilized to label cohorts of Sox9+ progenitors and their progeny with red fluorescent protein variant tdTomato. P0.5 brain section shows tdTomato (Ai14) cell labeling resulting from tamoxifen injection of dam at E11.5. (E11.5Tam; P0.5) (d) Cortex from an E11.5 Tam; P0.5 pup shows progeny of Sox9+ neural progenitors give rise to columnar arrangement of cortical neurons. (e a) Sox9 ^CreER;Ai14 labels progenitors with morphology characteristic of radial glial progenitors (RGPs). Ai14+ cells from an E16.5Tam; P0.5 pup includes radial glial progenitor (RGP) with endfoot on ventricular interface (arrowhead), which appears to have recently divided to form a new cell with visible leading process (asterisk). Scale bar: 10 μm. (e b) Ai14+ cells from E16.5Tam; P0.5 pup includes Tbr2+ IPs, as cells co-labeled for Ai14 (red) and Tbr2 (green) were observed (arrowheads). Scale bar: 10 μm