Expression of EGFP in hematopoietic organs is dependent on DOX. FACS analysis of adult spleen, bone marrow, thymus, and lymph nodes from double-transgenic effector/responder mice, demonstrating that the induction of EGFP was strictly dependent on DOX. Note the lack of EGFP⁺ cells in the FACS plots on the right where EGFP expression was inhibited by DOX. The percentage of EGFP-positive cells in each organ is indicated in the top right quadrant.