These floxed mutant mice possess loxP sites flanking exon 3 of the Flt1 gene. This strain may be useful for generating conditional mutations in applications related to the study of the angiogenesis and vasculogenesis.
Guo-Hua Fong, Univ CT Health Center
The Flt1 gene encodes the fms-like tyrosine kinase-1 (sFlt-1 or sVEGFR-1), which is a weak tyrosine kinase protein, and a truncated splice variant of VEGF receptor 1 (sFlt1/sVEGFR-1) lacking the transmembrane and kinase domains. As a high-affinity binding receptor for VEGF-A (vascular endothelial growth factor) but with no kinase activity, sFlt-1 is able to inhibit pro-angiogenic VEGF-A.
These mice possess loxP sites on either side of exon 3 of the targeted Flt1 gene. Exon 3 encodes the N-terminal half of the VEGF-A binding domain. Mice that are homozygous for this allele are viable and fertile. When these mutant mice are bred to mice that express Cre recombinase, resulting offspring will have exon 3 deleted in the cre-expressing tissues.
Removal of the floxed sequence creates a null allele.
When bred to a strain with widespread inducible Cre recombinase expression this mutant mouse strain may be useful in studies of vascular development.
The Vegfr-1 targeting vector was designed by Dr. Guo-Hua Fong (Univ CT Health Center) to contain, in the 5’ to 3’ direction, 5’ homology arm, loxP site, exon 3, loxP site, a FRT site flanked NEO cassette, and 3’ homology arm. This construct was electroporated into (129S6/SvEvTac x C57BL/6NCrl)F1 derived G4 embryonic stem (ES) cells and the resultant targeted clones were then transiently transfected with a Flpe recombinase vector to remove the selection cassette. ES cells that had successfully undergone Flpe recombination and no longer retained the selection cassette but did retain the loxP-flanked exon 3 were used to generate chimeras by aggregation technique using CD1 morula embryos. The resulting male chimeric animals were crossed to CD1 females. The mice were then backcrossed to C57BL/6 for 7 generations.
Upon arrival, sperm was cryopreserved. To establish our live colony, an aliquot of frozen sperm was used to fertilize C57BL/6J oocytes (Stock No. 000664).
|Allele Name||targeted mutation 1.1, Guo-Hua Fong|
|Allele Type||Targeted (Conditional ready (e.g. floxed), No functional change)|
|Gene Symbol and Name||Flt1, FMS-like tyrosine kinase 1|
|Strain of Origin||(129S6/SvEvTac x C57BL/6NCrl)F1|
|Molecular Note||A loxP site was inserted upstream of exon 3. An FRT-flanked neomycin resistance cassette with a 5' loxP site was inserted downstream of exon 3. Flp-mediated recombination removed the neomycin resistance cassette and left exon 3 floxed.|