STOCK Fgf3^tm1Lwd Fgf4^tm1.1Lwd/J

Stock number: 028716
Strain synonyms: Fgf3Δ -Fgf4flox -cis
Research areas: Cancer Research, Developmental Biology Research, Research Tools

Description

These Fgf3^Δ-Fgf4^flox mice carry a knock-out allele of the Fgf3 gene and a floxed allele of the Fgf4 gene in cis. When bred to a strain expressing Cre recombinase, the resulting offspring will have exons 2 and 3 of Fgf4 deleted in the cre-expressing tissues. These mice are suitable for useful for generating conditional mutations in applications related to the functional redundancy of Fgf3 and Fgf4 during embryogenesis, development and disease.

Detailed description

The targeted Fgf3 gene encodes an oncogenic fibroblast growth factor involved in inner ear development. Mutations in the Fgf3 gene have been associated with Deafness, Congenital With Inner Ear Agenesis, Microtia, And Microdontia and Deafness With Labyrinthine Aplasia Microtia And Microdontia. The targeted Fgf4 gene encodes an oncogenic fibroblast growth factor involved in limb development. Both Fgf3 and Fgf4 are important for embryonic axis extension. Mutations in the Fgf4 gene have been associated with Karposi sarcoma. Amplification and elevated levels of FGF3 and FGF4 is found in several types of cancer.

These mice carry a knock-out allele of the Fgf3 gene and a floxed allele of the Fgf4 gene, in cis (both genes are on Chromosome 7).

Fgf3^Δ-Fgf4^flox mice, homozygous for both alleles, are viable, fertile and exhibit shortened tail length compared to double heterozygotes and wildtype littermates. Circling or head-tilt behavior is incompletely penetrant in Fgf3^Δ-Fgf4^flox homozygotes.

When crossed to a strain with Cre recombinase expression in the mesodermal lineages, or germline Cre recombinase expression, this mutant mouse strain may be useful in studies of fibroblast growth factors during development.

Development

A targeting vector was used to insert an FRT-site flanked PGK-NEO cassette into intron 1, and loxP sites flanking exons 2 and 3 (including PGK-NEO cassette) of the Fgf4 gene. The construct was electroporated into (C57BL/6J x 129S4/SvJae)F1 derived v6.4 embryonic stem (ES) cells. Correctly targeted ES cells that were heterozygous for the floxed Fgf4^Neo allele were then retargeted and electroporated with a construct containing a hygromycin resistance cassette to disrupt the entire coding region of the Fgf3 gene. Correctly targeted ES cells containing both alleles in cis on the same (129) chromosome were injected into albino-B6 hosts (C57BL/6J-Tyr^c-Brd)blastocysts. The resulting chimeric animals were tested for germline transmission. Mice that were cis-heterozygous for both alleles were bred to β-actin-FLPe mice transgenic mice, on a C57BL/6, 129 and BALB/c background, to excise the FRT site flanked PGK-neo cassette. The resulting Fgf3^Δ-Fgf4^flox mice were then crossed to outbred NIH Swiss mice. cis-heterozygous mice that no longer carried the β-actin-FLPe transgene and no longer contained the PGK-neo cassette were then intercrossed to generate homozygotes. 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

Symbol: Fgf4^tm1.1Lwd
Name: targeted mutation 1.1, Mark Lewandoski
MGI accession ID: MGI:5888883
Generation method: Targeted
Attributes: Conditional ready (e.g. floxed)
Marker symbol: Fgf4
Marker name: fibroblast growth factor 4
Chromosome: 7
Strain of origin: (C57BL/6J x 129S4/SvJae)F1
Molecular note: A targeting vector is used to insert a loxP site and an FRT-site flanked PGK-NEO cassette into intron 1 followed by a second loxP site downstream of exon 3. Flp-mediated recombination removed the FRT-flanked neo cassette leaving exons 2 and 3 floxed.

Allele

Symbol: Fgf3^tm1Lwd
Name: targeted mutation 1, Mark Lewandoski
MGI accession ID: MGI:5888884
Generation method: Targeted
Attributes: Null/Knockout
Marker symbol: Fgf3
Marker name: fibroblast growth factor 3
Chromosome: 7
Strain of origin: (C57BL/6J x 129S4/SvJae)F1
Molecular note: A hygromycin B cassette is used to replace the coding region, starting 261 bp upstraim of the start codon and ending downstream of the stop codon (5810 bp total).
General note: This mutation was generated by re-targeting v6.4 ES cells in which Fgf4 had been targeted to create Fgf4^tm1.1Lwd. Both mutations were determined to be in cis on the 129 chromosome and are tightly linked. (J:229949)