Figure 1.

Generation of chimeric animals. A) Histologic analysis of donor engraftment. GFP positive (brown) donor cells were detected in the bone marrow. B) Fluorescence activated cell sorting representative analysis in which 95.4 ± 1.2% of nucleated blood cells were positive for GFP. C–E) Cells were isolated from bone marrow, and the plastic-adherent population was analyzed for GFP. Phase contrast (C), GFP (D), and merge images (E) are shown. Nearly all of the adherent cells were positive for GFP. F) DNA was extracted from isolated bone marrow cells. PCR amplification demonstrated that the floxed allele of Kif3a was amplified in the control animal with very faint amplification of wild-type Kif3a, indicating that the marrow stromal cell population was repopulated by transplantation. G) PCR amplification of marrow stromal cells isolated from tamoxifen-treated control animals demonstrated expression of the floxed allele of Kif3a, whereas experimental animals expressed the deleted Kif3a target, indicating successful deletion of Kif3a in the experimental group.