STOCK Fgf2^tm2Doe/J

Stock number: 010698
Product name: Fgf2^lmw-
Strain synonyms: 18-kDa FGF2KO
Research areas: Cardiovascular Research, Developmental Biology Research, Research Tools

Description

These Fgf2 knock-out mice may be useful in studying altered or pathological amounts of the Fgf2 low molecular weight isoform in bone development and growth, Wnt-signaling pathways, myocardial ischemia-reperfusion injury, and cardiovascular function.

Detailed description

Mice homozygous for the Fgf2^lmw-ko (Fgf2^lmw or FGF2 LMWKO) allele are viable and fertile with no reported abnormalities in endothelial cell migration and proliferation. As the targeted allele disrupts expression of the fibroblast growth factor 2 low molecular weight (Fgf2 lmw) isoform, the 18 kDa isoform is not expressed (as demonstrated in brain, aorta, lung, and endothelial cells from homozygous mice). The Fgf2 high molecular weight (hmw) isoforms (20.5 and 21 kDa) are still expressed in the nucleus from the targeted allele. Homozygous mice have significantly reduced bone mineral density and fewer mineralized nodules, coincident with increased expression of the Wnt antagonist secreted frizzled receptor 1 (sFRP-1) in bone tissue. Homozygous deficiency of the Fgf2 lmw isoform is associated with significantly impaired recovery in postischemic cardiac/contractile function after ischemia-reperfusion (I-R) injury.

Development

A targeting vector was designed to replace the canonical methionine translational ATG start site (CCATGG) in the first exon of the fibroblast growth factor 2 low molecular weight (Fgf2 lmw) core sequence common to all Fgf2 isoforms with an alanine-encoding CTGCAG PstI restriction site; preventing production of the Fgf2 lmw isoform. This construct was electroporated into 129P2/OlaHsd-derived E14TG2A embryonic stem (ES) cells (in which the first exon of Fgf2 had previously been replaced with an Hprt minigene). Targeted ES cells were then selected with 6-thioguanine and injected into recipient blastocysts. Chimeric males were bred with Black-Swiss females to generate the Fgf2^lmw-ko colony. Non-sibling heterozygous mice were bred together for approximately 20 generations prior to arrival at The Jackson Laboratory. Upon arrival, mice were bred to C57BL/6J (Stock No. 000664) for at least one generation to establish the colony.

Allele

Symbol: Fgf2^tm2Doe
Name: targeted mutation 2, Thomas Doetschman
MGI accession ID: MGI:3512180
Generation method: Targeted
Attributes: Null/Knockout
Marker symbol: Fgf2
Marker name: fibroblast growth factor 2
Chromosome: 3
Strain of origin: 129P2/OlaHsd
Molecular note: Exchange reaction of a Tag & Exchange targeting scheme 4 bp alteration without introduction of marker gene or loxP or frt sites. To produce this ko allele, the Hprt minigene in the tagged Fgf2 ko allele (Zhou et al, Nature Medicine, 4:201, 1998) was "exchanged" by gene targeting with a mutant exon 1 with the sequence CTGCAG replacing the wild-type CCATGC. The mutant sequence encodes an alanine GCA in place of the methionine ATG translational start site of the 18-kDa low molecular weight isoform. The adjacent upstream wobble base was also changed from C to T so that the composite of these three base changes generated a PstI site that is diagnostic for the exchanged allele. Cells with the exchanged allele were selected for the loss of HPRT function using 5 mg/mL 6-thioguanine. There are no LoxP, Frt or marker gene sequences in this new allele.
General note: E14TG2a congenic line with one Fgf2 ko allele was used to produce this allele.