Nex-CRE mice induce recombination in cortical neurons but not in glia. a, b, Sagittal sections through the cortex were stained for LacZ (blue) and GFAP (brown). GFAP-positive cells (arrowheads) were LacZ negative. Arrows point to LacZ-positive cells that were interspersed between GFAP-positive cells; cc, corpus callosum. d–f, Sagittal cortical sections were stained for LacZ (blue) and NeuN (brown). LacZ-positive cells were NeuN positive, confirming their identity as neurons. Note that LacZ staining in d–f was for a shorter time than in a and b. Therefore, the signal appeared less strong and less diffuse in d–f, revealing strong staining in one or two dots within nuclei (arrows in f). c, g, Cortical neurons and glial cells from P0 mice were cultured on PDL/LN substrates and stained. c, LacZ-positive cells (blue) were interspersed between GFAP-positive cells (brown). g, MAP2-positive neurons (red), expressed CRE (green) in nuclei. Scale bars: a, 330 μm; b, c, 23 μm; d, 115 μm; e, 30 μm; f, g, 18 μm.