The Rosa26-LSL-Rac1b allele contains a loxP-flanked neo-STOP cassette upstream of human RAS-related C3 botulinum substrate 1 (Rac1) isoform b cDNA inserted into the Gt(ROSA)26Sor locus. The Rac proteins regulate signaling pathways that control the shape, motility and growth of cells. Mice homozygous for the Rosa26-LSL-Rac1b allele are viable and fertile. Rac1b is a GTP-bound, active Rac1 splice variant which has been found to be upregulated in colon and breast cancer cells. In the absence of Cre, RAC1 expression is prevented by the floxed STOP sequence. After removal of the loxP-flanked STOP cassette via cre-mediated recombination, RAC1 expression is evident in the cre-expressing tissues of the offspring. For example, when these mice receive an intranasal instillation of a cre-expressing adenovirus, the removal of the STOP cassette in the lung results in RAC1 expression. These inoculated mice show no overt phenotype. When bred to B6.129S4-Krastm4Tyj/J mice (Stock No. <a href="https://www.jax.org/strain/008179">008179</a>), expressing a cre-inducible oncogenic K-ras allele, intranasal instillation of a cre-expressing adenovirus results in the initiation and progression of lung tumors with an increase in the tumor volume to lung volume ratio above that of the oncogenic K-ras allele alone.

These Rosa26-LSL-Rac1b mice allow for the conditional expression of a Rac1 isoform b cDNA. They may be useful in applications associated with the initiation and progression of tumorigenesis.

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

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