Overview and distribution of distinct precursor cells in the dentate gyrus of the transgenic nestin-GFP mouse. (A) labelled for bromodeoxyuridine (BrdU; red), green fluorescent protein (GFP; green) and glial fibrillary protein (GFAP; blue). Scale bar represent 100 μm. (B) Schematic illustration of distinct precursor cell subtypes leading to new neurons in the dentate gyrus. Type 1 cells exhibit characteristic morphology with a triangle-shaped soma, long and strong apical processes reaching into the granular cell layer (GCL). These radial glia-like cells express precursor cell markers like nestin and additionally the astrocytic marker glial fibrillary protein (GFAP). Arising from type 1 cells transient amplifying progenitor cells (type 2) express nestin, have plump, short processes orientated parallel to the subgranular zone (SGZ). They do not express GFAP. Type 2 cells exist in two subtypes, one negative (type 2a) and one positive for doublecortin (DCX) (type 2b). While type 2 cells express the marker nestin, type 3 cells are only positive for doublecortin and comprise a transition from a proliferative stage to postmitotic immature neurons. After exit from the cell cycle the terminal post mitotic differentiation of granular cells start the NeuN marker expression for mature neurons. (C) Confocal images of double- and triple-labelled immunofluorescent sections showing the distinct cell types (marked with dotted rectangles). Scale bars represent 10 μm. SGZ, subgranular zone; GCL, granular cell layer.