STOCK Vegfa^tm2.1Nagy/J

Stock number: 027315
Product name: VEGF^hypo
Research areas: Cardiovascular Research, Developmental Biology Research, Research Tools

Description

This VEGF-A hypomorphic strain, VEGF^lo, has reduced expression of Vegfa and functions as a reporter strain for VEGF positive cells and tissues during embryonic vascular development.

Detailed description

Vascular endothelial growth factor A is a mitogenic glycoprotein specific for endothelial cells and is involved in vascular permeability, angiogenesis, vasculogenesis, cell migration, as well as endothelial cell growth. These VEGF^hypo (VEGF^lo) mice carry an IRES-beta-galactosidase knock in mutation of the Vegfa gene. Mutant mRNA is detected by RT-PCR analysis of homozygous embryos. The last six C-terminal amino acid residues of the protein, encoded by exon 8, are replaced by 66 amino acids encoded by lacZ. Other aberrant splicing events are also detected. VEGF-A protein activity is significantly reduced (25 % to 50%) in heterozygotes compared to controls, as determined by RT-PCR of calf and collateral zone adductor muscles.

Mice that are homozygous for the targeted knock-in allele have an embryonic lethal phenotype, dying between 9.5 and 11.0 dpc due to systemic cardiovascular defects. Homozygous embryos exhibit disorganized yolk sac vasculature, delayed heart development, reduced dorsal aorta lumen, fewer vascular endothelial cells, and pancytopenia (reduced number of blood cells). Mice that are heterozygous for the targeted mutation are viable and fertile. Heterozygotes exhibit reduced angiogenic sprouting during development. After hindlimb ischemia or cerebral artery ligation, heterozygotes have lower perfusion with diminished recovery, collateral remodeling, and angiogenesis compared to wildtype controls.

Beta-galactosidase activity is similar to that observed in the VEGF-LacZ KI-Δneo strain (Stock No. 027314). The lacZ reporter expression mimics the endogenous Vegfa gene expression pattern during development and adulthood.

Development

A targeting vector containing an IRES-lacZ cassette, and floxed PGK-NEO, was inserted into the 3' UTR (noncoding region of exon 8) of the Vegfa gene, directly adjacent to the stop codon. The construct was electroporated into 129 derived R1 embryonic stem (ES) cells. Chimeric mice were generated by aggregating correctly targeted ES cells with CD-1 morula-stage embryos. The resulting heterozygotes were crossed to CMV-Cre transgenic mice (most likely on the CD-1 genetic background) to remove the loxP site flanked NEO cassette. The mice were then crossed to CD-1. Upon arrival at The Jackson Laboratory, the mice were crossed to 129S1/SvImJ (Stock No. 002448) at least once to establish the colony.

Allele

Symbol: Vegfa^tm2.1Nagy
Name: targeted mutation 2.1, Andras Nagy
MGI accession ID: MGI:2383985
Generation method: Targeted
Attributes: Reporter; Null/Knockout
Marker symbol: Vegfa
Marker name: vascular endothelial growth factor A
Chromosome: 17
Strain of origin: (129X1/SvJ x 129S1/Sv)F1-Kitl⁺
Expressed genes: Vegfa,vascular endothelial growth factor A,mouse, laboratory; lacZ,beta-galactosidase,E. coli
Site of expression: Endothelial cells
Molecular note: The mutant is a derivative of Vegf1^tm2Nagy where the floxed PGK-neo cassette in exon 8 has been removed by mating to a cre deletor strain.