These transgenic mice express tamoxifen-inducible Cre recombinase, cre/ERT2, and DsRed Express 2 fluorescent protein under the control of the 3.2 kb mouse Col1a1, collagen, type I, alpha 1, gene promoter. 
Transgene expression is detected in osteoblasts, odontoblasts, some osteocytes and some tendon cells. Tamoxifen treatment of pregnant females when embryos are E13.5 results in a recombination activity pattern that mimics the red fluorescence expression pattern. Transgene expression in embryos, aged E15.5, is detected in calvaria frontal and parietal bones. 

Mice that are homozygous for the transgene are viable and fertile. 
The Donating Investigator reports there is no difference between the phenotype exhibited by homozygotes compared to hemizygotes.
During backcrossing, the Y chromosome may not have been fixed to the C57BL/6 genetic background.
The Cre-ERT2 fusion protein consists of Cre recombinase fused to a triple mutant form of the human estrogen receptor which does not bind its natural ligand (17&beta;-estradiol) at physiological concentrations but will bind the synthetic estrogen receptor ligands 4-hydroxytamoxifen (OHT or tamoxifen) and, with lesser sensitivity, ICI 182780. Restricted to the cytoplasm, Cre-ERT2 can only gain access to the nuclear compartment after exposure to tamoxifen. To counteract the mixed estrogen agonist effects of tamoxifen injections, which can result in late fetal abortions in pregnant mice, progesterone may be coadministered.

This Col1a1CreER-DsRed mutant mouse strain carries a transgene with tamoxifen inducible Cre recombinase and may be useful for generating osteoblast specific targeted mutants for studies of cartilage and bone development.

Typically mice are recovered in 12-16 weeks. Contact Customer Service to place an order or for more information.

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