GFP-positive cells show cell surface markers characteristic to hematopoietic progenitors. The 7.0ISGFP transgenic mouse embryos (line 398) were analyzed. Yolk sac from 10.5 dpc embryos (A), AGM regions from 10.5 dpc embryos (B and C), and liver rudiments from 10.5 and 11.0 dpc embryos (B and C) were dissected, and single-cell suspensions from the tissues were analyzed by FACS directly (A) or after staining with monoclonal antibodies (B and C). PE-conjugated anti-Sca1, anti-CD45, and anti–c-kit antibodies (B), and biotin-conjugated anti-CD34, anti–flk-1, and anti-Ter119 antibodies and streptoavidine-APC were used (C). IgG2b antibody was used as a control.