Figure 4.

Reporter mice successfully label NG2+ cells that can be followed for at least 3 weeks after recombination. A, Schematic of breeding paradigm to generate PDGFRα-CreER:mT/mG mice. PDGFRα-CreER mice were crossed with ROSA26-mGFP (mT/mG) mice to generate mice that ubiquitously express mT. Upon recombination by oral administration of tamoxifen, most cells expressing the PDGFRα promoter begin to express mG (∼90%) and downregulate mT. pCA, Promoter with CMV enhancer; pA, polyadenylation sequences; arrows indicate the direction of transcription. Single-channel and merged confocal images of GFP+ NG2 cells in naive spinal cord white (B) and gray (C) matter. Single-channel and merged confocal images of GFP+ NG2 cells from spared white matter labeled at 1 wpi and examined at 4 wpi (D), labeled at 2 wpi and examined at 5 wpi (E), or labeled at 4 wpi and examined at 7 wpi. F, Low-power visual comparison of naive (G) and injured spinal cord (7 wpi, 250 μm rostral to the epicenter; H) labeled with GFP and NG2. Nuclei are labeled with DAPI in blue. Scale bars: B, D, E, 50 μm; C, G, H, 100 μm; F, 10 μm.