These transgenic mice express a tamoxifen-inducible Cre recombinase (cre/ERT) driven by the mouse Ins1, insulin I, promoter. Restricted to the cytoplasm, the cre/ERT protein can only gain access to the nuclear compartment after exposure to tamoxifen. When crossed with a strain containing a loxP site flanked sequence, the offspring are useful for generating tamoxifen-induced, Cre-mediated targeted deletions of the flanked sequence. Inducible Cre recombinase activity is detected specifically in the pancreatic beta cells, and is not detected in the brain, pancreatic alpha cells, liver, fat, skeletal muscle, spleen, lungs, small intestine, large intestine, kidney, heart, eyes, testes or ovaries. No alteration of pancreatic beta cell physiology is detected. The Donating Investigator has not attempted to make the strain homozygous.
