Bone marrow derived cells can migrate to the rat normal hippocampus. Sixteen months after injection of SV (Nef-FLAG) into the rat bone marrow (BM), transgene expressing cells were detected in the dentate gyrus (DG). A: FLAG-positive cells colocalized with NeuN, a marker of mature neurons. FLAG+/NeuN+ cells were located in the granular cell layer (GCL), as well as in the subgranular zone (SGZ) and the hilus. No FLAG-expressing cells were detected in the brain after injection of SV (BUGT), a control vector, in the BM; B: Nestin+/FLAG+ cells were detected mainly at the border SGZ/GCL, and more rarely in the GCL (arrows); C: DCX+ positive cells expressing FLAG were seen at the border SGZ/GCL and more rarely in the GCL (arrows). Note that some FLAG+ cells were DCX-, and were probably mature neurons (arrowheads). In all experiments, nuclei were stained in blue by Vectashield containing DAPI.