NFATC1 and leukemia: To this end, transgenic NFAT mice, harboring a hemagglutinin (HA)-tagged constitutively nuclear (c.n.)human NFATC1 cDNA under the control of a loxP–STOP–loxP cassette in the ROSA26 locus [7] were crossed with Cre-transgenic mice (Cre-ERT mice [24, 25]), in which tamoxifen-inducible Cre-ERT recombinase is expressed under the control of the stem cell leukemia (Scl ) enhancer (SCL-Cre-ERT) and transgenic Flt3ITD mice [19], thus targeting NFATC1 expression to Flt3ITD-positive hematopoietic stem cells.