The construct containing cathepsin K (Ctsk) driving Red Fluorescent Protein (RFP) and cre/ERT2 fusion gene was used to create a transgenic line in C57BL/6 mouse. Cre recombinase is activated in bone, brain, eyes, kidney, adrenal gland, lung, spleen, thymus, stomach, pancreas, skeleton muscle, small intestine, appendix, epididymis, white and brown fat, and skin after tamoxifen-induced.