STOCK Angpt1^tm1.1Sjm/J

Stock number: 028924
Product name: Angpt1^GFP
Research areas: Research Tools

Description

Angpt1^GFP knock-in/knock-out mice express a GFP reporter in hematopoietic stem cells and the surrounding stromal cells in bone marrow. These mice are useful in studies of hematopoietic stem cell/marrow regeneration post radiation therapy.

Detailed description

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.

These knock-in/knock-out mice express a GFP reporter from the mouse Angpt1 promoter in hematopoietic stem cells and the surrounding stromal cells in bone marrow. GFP can be readily detected in KIT⁺ hematopoietic progenitor cells and bone marrow stromal cells by flow cytometry. For imaging on sections, one needs an anti-GFP antibody to make GFP visible. GFP is expressed by CD41⁺ megakaryocytes and KIT⁺ (c-kit⁺) hematopoietic progenitor cells throughout the bone marrow. Virtually all of the ANGPT1 expression by stromal cells is by LEPR⁺ cells which localize mainly around sinusoids, as well as near arterioles. Nearly all PDGFRA⁺ cells (indicative of mesenchymal stem/stromal cells) are GFP⁺. GFP expression is not detected in endothelial cells or osteopontin⁺ bone lining cells in the diaphysis or metaphysis.

Crosses of Angpt1^GFP heterozygotes produce no viable homozygous progeny, suggesting this is a strong loss-of-function allele.

Development

Exon 1 was replaced by a GFP-pA-FRT-neo-FRT knock-in cassette inserted in frame with the Angpt1 ATG start codon. The mutation was created via homologous recombination in B6.Cg-Thy1^a-derived Bruce 4 embryonic stem (ES) cells. Resultant chimeric mice were bred with B6(Cg)-Tyr^c-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). This line was backcrossed to C57BL/Ka for more than 10 generations by the donating laboratory. The albino allele is no longer carried 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

Symbol: Angpt1^tm1.1Sjm
Name: targeted mutation 1.1, Sean J Morrison
MGI accession ID: MGI:5749672
Generation method: Targeted
Attributes: Reporter; Null/Knockout
Marker symbol: Angpt1
Marker name: angiopoietin 1
Chromosome: 15
Strain of origin: B6.Cg-Thy1^a
Expressed genes: GFP,Green Fluorescent Protein,
Site of expression: GFP is expressed in KIT+ hematopoietic progenitor cells and bone marrow stromal cells.
Molecular note: A GFP gene, polyA sequence and FRT flanked neo cassette replaced the coding region of exon 1, in-frame with the ATG start codon. Flp mediated recombination removed the neo cassette.