The Foxp3 promoter drives the expression of Red Fluorescent Protein (RFP) and Cre recombinase. RFP expression is detected in CD4+CD25+ cells. Cre activity is observed in thymus, Peyer's patch, lymph nodes of neck, iliac and mesentery, spleen, lung, small intestine, appendix, testis, epidiymis, and brown fat. (J:221795)