Figure 1

Sox9 expression coincides with markers for neural progenitors, RGCs and Bergmann glia during mouse cerebellum development as revealed by immunofluorescence staining of cerebellar sagittal sections from E11.5 to P5. (A, A’) At E11.5, Sox9 immunoreactivity could be observed in the entire cerebellar primordium, covering the newly specified VZ and RL. (B, B’) At E13.5, Sox9 expression became restricted to the VZ, while traces of Sox9+ cells were also found in the RL. (C, C’) Sox9 expression persisted throughout gestation at the VZ. From E15.5 onwards, Sox9 could also be detected in cells that had delaminated from the VZ as they migrate to the Purkinje cell plate at E18.5. (A’-C’) Magnified view of the corresponding VZ region marked by dotted square in A-C. Almost all the Sox9 expressing cells were immmunoreactive for the neural stem cell marker Sox2 throughout the embryonic cerebellum development. (D and E) Co-localization of Sox9 with the glial marker was observed from E13.5 to E18.5. (D’) At E13.5, EAAT1 was predominantly localized to the VZ where the Sox9+ radial glial cells reside. (E’) After the onset of astrogliogenesis, the majority of EAAT1 expression at E18.5 was found at the PCL where the Bergmann glial cells locate. (F and F’) By P5, Sox9 signal was found predominantly at the PCL, where it labeled the soma of GFAP⁺ Bergmann glial cells. Abbreviations: egl, external granular layer; igl, internal granular layer; pcl, Purkinje cell layer; ml, molecular layer; rl, rhombic lip; vz, ventricular zone. Scale bars: A-F, 100 μm; A’-F’, 50 μm.