C57BL/6-Tg(Csf1r-EGFP-NGFR/FKBP1A/TNFRSF6)2Bck/J

Stock number: 005070
Product name: Macrophage Fas-Induced Apoptosis (MaFIA)
Research areas: Immunology, Inflammation and Autoimmunity Research, Research Tools

Description

These macrophage Fas-Induced apoptosis (MaFIA) transgenic mice allow inducible/reversible apoptosis of macrophages and dendritic cells using the mouse colony stimulating factor 1 receptor promoter (Csf1r) to drive expression of a mutant human FK506 binding protein 1A, 12kDa. The transgene also allows fluorescent labeling of Csf1r-expressing cells. These mice may be useful in investigating the role of macrophages and dendritic cells.

Detailed description

These Macrophage Fas-Induced Apoptosis (MAFIA) transgenic mice have an inducible Fas suicide/ apoptotic system driven by the mouse Csf1r, colony stimulating factor 1 receptor promoter. The transgene insert contains a mutant human FK506 binding protein 1A, 12kDa (FKBP12) which preferentially binds the dimerization drug AP20187. Enhanced Green Fluorescent Protein (EGFP) fluorescence and transgene expression is detected in 78% of isolated peritoneal cells. EGFP fluorescence is variable among tissues (B- and T-cells do not express EGFP). Administration of the dimerizing reagent, AP20187, induces apoptosis in macrophages and dendritic cells (intravenous injection of dimerizer is recommended, since the intraperitoneal route can elicit peritoneal adhesions [Burnett et al. 2006 J Surg Res. 131:296]). In treated mice, EGFP fluorescing peritoneal and bone marrow macrophage numbers are depleted by more than 90%, and macrophage numbers in blood, spleen, lung and thymus by more than 70%. 7 days after cessation of treatment, the EGFP fluorescing macrophage and dendritic cell populations rebound. Homozygous mutant mice are viable, fertile, normal in size and do not display any gross physical or behavioral abnormalities. Prior to June 2008, this strain may have contained multiple transgene insertion sites (about which the donating investigator recommended that all offspring be screened for EGFP expression [via flow cytometry]). By June 2008, the live MAFIA mouse colony at The Jackson Laboratory Repository was confirmed to have one transgene integration site and retained the ability for inducible macrophage deletion.

Development

An FKBP-Fas suicide construct (containing an IRES sequence, human low affinity nerve growth factor receptor [deltaLNGFR], 2 copies of the 12kDa human FK506 binding protein 1A [FKBP12], and the intracellular domain region of the Fas gene) was inserted immediately downstream of the Enhanced Green Fluorescent Protein (EGFP, Clonetech) gene. This entire construct was placed under the control of the mouse colony stimulating factor 1 receptor (Csf1r) promoter. The resulting 11.1 kbp transgene (termed Macrophage Fas-Induced Apoptosis or MaFIA) was introduced into C57BL/6 donor eggs. The resulting male transgenic mice (founder line 2) were bred to C57BL/6 mice for six generations prior to arrival at The Jackson Laboratory Repository in 2004. Prior to June 2008, this strain may have contained multiple transgene insertion sites. By June 2008, the live MAFIA mouse colony at The Jackson Laboratory Repository was confirmed to have one transgene integration site and retained the ability for inducible macrophage deletion.

In 2021, a 48 SNP (single nucleotide polymorphism) panel analysis, with 43 markers covering all 19 chromosomes and the X chromosome, as well as 5 markers that distinguish between the C57BL/6J and C57BL/6N substrains, was performed on the rederived living colony at The Jackson Laboratory Repository. Four of the 5 markers that determine C57BL/6J from C57BL/6N were found to be segregating, including the rd8 recessive mutation associated with retinal degeneration on Chromosome 1 within the Crb1 locus. These data suggest the mice sent to The Jackson Laboratory Repository were on a mixed C57BL/6N;C57BL/6J genetic background.

Allele

Symbol: Tg(Csf1r-EGFP-NGFR/FKBP1A/TNFRSF6)2Bck
Name: transgene insertion 2, Donald A Cohen
MGI accession ID: MGI:3051865
Generation method: Transgenic
Attributes: Reporter; Inserted expressed sequence; Humanized sequence
Marker symbol: Tg(Csf1r-EGFP-NGFR/FKBP1A/TNFRSF6)2Bck
Marker name: transgene insertion 2, Donald A Cohen
Chromosome: UN
Strain of origin: C57BL/6
Expressed genes: GFP,Green Fluorescent Protein,; NGFR,nerve growth factor receptor,human; TNFRSF6B,TNF receptor superfamily member 6b,human; FKBP1A,FK506 binding protein 1A,human
Site of expression: Expression of GFP and the NGFR/FKBP12 transgene is detected in 78% of isolated peritoneal cells. GFP expression is variable among tissues. B and T cells do not express GFP. Administration of AP20187 induces apoptosis inmacrophages and dendritic cells.
Molecular note: The transgene's bicistronic transcript, expressed from the promoter of the macrophage-expressed colony stimulating factor 1 receptor gene, encodes enhanced green fluorescent protein (EGFP) and a conditionally apoptotic fusion protein. The latter comprises the extracellular and transmembrane domains of the human low affinity nerve growth factor receptor, two tandem copies of the human FK506 binding protein, and the intracellular domain of human TNFRSF6 - the Fas receptor protein - and is translated from an internal RNA expression signal (IRES) inserted at the translation start codon of the nerve growth factor receptor (NGFR) coding sequence.
General note: Homozygous mutant mice are viable, fertile, normal in size, and do not display any gross physical or behavioral abnormalities.

The transgene is expressed constitutively in macrophages and dendritic cells and permits conditional ablation of these cell populations in the mouse. Oligomerization of the fusion protein by binding of a bivalent FK506 analog causes them to undergo apoptosis via the Fas-mediated pathway.

In transgenic mice treated with the dimerizing reagent AP20187, EGFP fluorescing peritoneal and bone marrow macrophage numbers are depleted by more than 90%, and macrophage numbers in blood, spleen, lung and thymus by more than 70%. Seven days after cessation of treatment, the EGFP fluorescing macrophage and dendritic cell populations rebound.