These mice contain the Cot2 (Cre or Tomato on chromosome 2) allele and the cre-inducible R26R-EYFP allele. Specifically, the Cot2 allele contains a tdTomato and a cre gene, fused to an EGFP, in a FLP recombinase inducible system. When used in combination with a FLP expressing strain, these mice function as an integral part of the MASCOT (mosaic analysis system with Cre or Tomato) system, enabling the temporally controlled introduction of mosaicism and fluorescent markers to a tissue of interest. The MASCOT system consists of three distinct alleles: 1) R26FlpoER (Stock No. <a href="https://www.jax.org/strain/019016">019016</a>), which initiates mosaicism (activation of cre or tdTomato) in all cell types upon tamoxifen treatment; 2) the Cot2 MASCOT reporter that drives either the tdTomato marker or cre in response to FLP-directed recombination; and 3) a cre-dependent fluorescent reporter (similar to Stock No. <a href="https://www.jax.org/strain/006148">006148</a>) for tracing cre-expressing cells. By combining these three different alleles with a loxP-based conditional strain, one can delineate the cell-autonomous functions of any gene in different tissues at a desired time point in embryonic development or postnatal life, including in disease models. In mice harboring Cot2, the R26FlpoER allele, and a Cre-dependent reporter (in this case EYFP), 20 to 30% of cells in the hematopoietic compartment are labelled following three rounds of tamoxifen treatment, and tdTomato+ and EYFP+ single-positive cells can be induced at similar frequency in a wildtype background. By quantifying the percentage of tdTomato+ and EYFP+ clones, it is possible to determine whether the mutant clone marked by EYFP leads to clonal expansion, contraction, or neutrality. The incorporation of tdTomato as an independent fluorescent marker for wildtype cells, as opposed to the labeling of solely the mutant clones with EGFP, provides an internal control to compare the phenotypes of mutant and wildtype clones in the same animal. Fluorescence is detectable by fluorescent microscopy and flow cytometry. Homozygotes are viable and fertile.

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These mice contain the Cot2 (Cre or Tomato on chromosome 2) allele and the cre-inducible R26R-EYFP allele. Specifically, the Cot2 allele contains a tdTomato and a cre gene, fused to an EGFP, in a FLP recombinase inducible system. When used in combination with a FLP expressing strain, these mice function as an integral part of the MASCOT (mosaic analysis system with Cre or Tomato) system, enabling the temporally controlled introduction of mosaicism and fluorescent markers to a tissue of interest.

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

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