These transgenic mice express Cre recombinase under the control of the mouse Car1, carbonic anhydrase 1, promoter. Transgenic transcript is detected in the tissues of the large intestine (cecum, proxmial and distal colon) by RT-PCR. Low levels of transcript are detected in the liver, and no transgene transcript is detected in kidney, stomach, bone marrow, prostate, lung, thymus, liver hear, duodenum, jejunum, ileum, pancreas, spleen.
Mosaic recombinase activity is detected as early as 14.5 dpc in approximately 15% of the epithelial cells of the large intestine and is observed in individual crypts from the base to lumen. When crossed with a strain containing loxP site-flanked sequences, cre-mediated recombination results in large intestine epithelial-specific deletion of the flanked sequences in the offspring. Mice that are homozygous for the transgene are viable, normal in size and do not display any gross physical or behavioral abnormalities.
