Exon 1 of the mouse Angpt1 gene is flanked by loxP sites in this Angpt1fl allele. Cre-mediated excision of the floxed exon produces a knock-out allele useful in studies of hematopoietic stem cell/marrow regeneration post radiation therapy.
Sean J Morrison, University of Texas Southwestern Medical Center
Protein encoded by the Angpt1 (angiopoietin 1) gene is expressed by hematopoietic stem cells of the bone marrow. It is believed that after cancer radiation treatment, this expression slows the regeneration of blood vessels in the surrounding niche, thus reducing their leakiness.
In this Angpt1fl allele, exon 1 (containing the translational start codon) is flanked by loxP sites. Cre-mediated excision of the floxed region (e.g. via crosses with CMV-cre mice) results in a knock-out allele which does not produce mRNA, as determined by qPCR of fetal liver. Animals homozygous for a complete knockout are not viable, consistent with a reported E12.5 lethality phenotype.
Deletion of Angpt1 from hematopoietic cells and LEPR+ cells has little effect on vasculature or HSC frequency under steady-state conditions but accelerates
vascular and hematopoietic recovery after irradiation while increasing vascular leakiness.
An FRT-Neo-FRT-loxP cassette was inserted 5' of exon 1 and a loxP site was inserted 3' of exon 1 via homologous recombination in B6.Cg-Thy1a-derived Bruce 4 embryonic stem (ES) cells. Resultant chimeric mice were bred with B6(Cg)-Tyrc-2J/J animals (see Stock No. 000058) to obtain germline transmission. The FRT-flanked neomycin cassette was removed through crosses with Tg(ACTFLPe)9205Dym mice (see Stock No. 005703), leaving exon 1 flanked by loxP sites. This line was backcrossed to C57BL/Ka for more than 10 generations by the donating laboratory. The albino allele is no longer seen in their colony.
This C57BL/Ka background strain will be cryopreserved as sperm at The Jackson Laboratory, and likely recovered using C57BL/6J females.
|Allele Name||targeted mutation 2.1, Sean J Morrison|
|Allele Type||Targeted (Conditional ready (e.g. floxed))|
|Gene Symbol and Name||Angpt1, angiopoietin 1|
|Strain of Origin||B6.Cg-Thy1a|
|Molecular Note||An FRT flanked neo cassette and loxP site were inserted upstream of exon 1 and a loxP site was inserted downstream of exon 1 via homologous recombination. Flp mediated recombination removed the neo cassette.|
Heterozygous and homozygous floxed mice are viable and fertile.
When using the Angpt1fl mouse strain in a publication, please cite the originating article(s) and include JAX stock #028925 in your Materials and Methods section.