Figure 1.

NG2 glia in embryonic and adult brain.

The distribution of embryonic and adult NG2 glia in the brain demonstrated in NG2-CreERT2^Huang KIxRosa26-tdTomato mice. In the embryonic brain, of the NG2 gene started in a small portion of OPCs in the ventral brain. When Cre activity was induced at E14.5 and analyzed at E16.5 (E14.5:E16.5), tdTomato (tdT) expression was found in PDGFRα⁺ OPCs (therefore termed NG2 glia) and vascular pericytes (A, a₁–a₄). Most tdT⁺ NG2 glia were detected in the ventral brain (A, a₂, and a₄, arrowheads) and few were found in the dorsal cortex (A, a₁, and a₃, arrowheads). Nevertheless, vascular tdT⁺ pericytes were observed in the whole brain (A, a₁–a₄, arrows). In adult brain at P30:P80, tdT⁺ NG2 glia were found equally distributed in the brain, irrespective of dorsal or ventral regions (B, b₁, b₂). Some NeuN⁺ tdT⁺ cells with typical neuronal morphology were sporadically located in the cortex (b₃, triangle). However, only few tdT⁺ cells (~0.5%, 5 out of 946 cells analyzed from three mice) were NeuN immunopositive in the hypothalamus (b₄, triangle). Scale bars: 500 μm in A and B; 100 μm in a₂, and b₂; 20 μm in a₄, and b₄ (unpublished data from Huang et al., 2014, 2019).