TG-GFP⁺ cells from the AGM region have hematogenic activity. (A) TG-GFP⁺/CD45⁺ and TG-GFP⁺/CD45^- cell fractions of the AGM region were sorted by FACS. (B-C) Phase-contrast microscopy analysis of hematopoietic colonies with a cobblestone-like appearance after 4 days of coculture with OP-9 cells. Cells in panel B are from the TG-GFP⁺/CD45⁺ fraction, while cells in panel C are from the TG-GFP⁺/CD45^- fraction. The number of colony-forming cells is shown in Table 1. (D) Appearance of TG-GFP⁺/CD45^- cell colonies. TG-GFP⁺/CD45^- cells were cultured in medium containing OSM, SCF, b-FGF, and LIF. Note that colonies contain both adherent cells (dark cells) and floating cells (bright cells). (E) Flow cytometric analysis of the cells in panel D. Majority of the cells show abundant CD45 expression without GFP fluorescence. Original magnification, panels B-D, × 100.