Figure 2

TDO immunoreactivity in progenitor cells. A: The immunoreactivity of a type I progenitor cell marker, glial fibrillary acidic protein (GFAP), was rarely observed in TDO-expressing cells. B: Cells double-labeled with Ki67 and TDO were scarcely observed (arrowhead). C: Co-expression of TDO with doublecortin (DCX). Few DCX-positive (+) cells in the subgranular zone, which comprises type 2 progenitor cells, contained TDO. In contrast, DCX+ cells that integrated into the granule cell layer, which comprises postmitotic immature neurons, co-expressed TDO (arrows). g, granule cell layer; h, hilus.