Identification of BM-derived vector-expressing cells in the CNS of treated Glb1^-/- mice. Immunofluorescence analyses were done on single cryostatic sections from the brains of treated Glb1^-/- mice. Fluorescent signals from single sections were sequentially acquired and are shown individually and after merging. (A-B) GFP⁺ cells and β-gal⁺ cells were identified as microglia by F4/80 immunoreactivity in Glb1^-/- mice 3 months after BMT. (C) Overlay of β-gal staining with the neuronal-specific marker NeuN demonstrated colocalization of the 2 signals, a finding that indicates cross-correction of the enzyme-deficient neurons. Size bar corresponds to 50 μm. Image acquisition was performed as described for Figure 3.