Figure 3

Glast⁺ radial glia generate the majority of neurons in the brain. (a-o) X-gal histochemical staining for β-gal activity (a,b,f,g,k,l) and immunofluorescent staining for NeuN (red) (c,e,h,j), β-galactosidase (green; d,e,i,j,n,o) and Calbindin (red) (m,o) in hGFAP::Cre;R26R (a,f,k) or Glast::Cre;R26R (b-e,g-j,l-o) adult mice. Regions immunofluorescently stained are striatum (c-e), thalamus (h-j) and cerebellum (m-o). In hGFAP::Cre;R26R mice, very few recombined neurons are present in the ventral telencephalon, diencephalon or midbrain, and cerebellar Purkinje neurons are unrecombined (a,f,k). PCL, Purkinje cell layer. In contrast, neuronal recombination was extensive throughout the brains of Glast::Cre;R26R mice (b,g,l) and double labeling confirmed that most neurons were recombined (c-e,h-j,m-o). The similarity of the Glast::Cre;R26R and Blbp::Cre;R26R lineage tracing results establishes that radial glia are the primary neuronal progenitors throughout the developing brain. Scale bars: 500 μm (a,b,f,g); 50 μm (k,l); 35 μm (m-o); 25 μm (c-e,h-j).