B6;129-Abcg2^{tm3.1(cre/ERT2)Bsor}/J

Stock number: 021961
Research areas: Developmental Biology Research, Research Tools

Description

An internal ribosome entry site (IRES)-CreERT2 fusion protein and a polyadenylation signal were placed downstream of the endogenous stop codon of the ATP-binding cassette, sub-family G (WHITE), member 2 Abcg2 gene. These mice may be useful for hematopoietic lineage tracking.

Detailed description

In this strain, an internal ribosome entry site (IRES)-CreERT2 fusion protein and a polyadenylation signal were placed downstream of the endogenous stop codon of the ATP-binding cassette, sub-family G (WHITE), member 2 Abcg2 gene. ABCG2 is a transporter expressed in hematopoietic stem cells and is involved in cellular detoxification and protection from toxins. Homozygotes are viable and fertile. Cre expression is seen in hematopoietic cells of renal proximal tubules, testicular germ cells, small intestine, liver, and cardiac and skeletal muscle. Reduced expression is seen in the kidney and liver compared to wildtype. When these mice are bred with mice containing loxP-flanked sequence, tamoxifen-inducible, Cre-mediated recombination will result in deletion of the floxed sequences in the ABCG2-expressing cells of the offspring, as well as all progeny arising from these cells.

Development

A targeting vector was designed to insert a loxP-flanked neomycin resistance cassette in reverse orientation, an internal ribosome entry site (IRES)-CreERT2 fusion protein, and a polyadenylation signal downstream of the endogenous stop codon of the ATP-binding cassette, sub-family G (WHITE), member 2 Abcg2 gene. The construct was electroporated into ES129SVJ-F12-derived embryonic stem (ES) cells. Correctly targeted ES cells were transiently transfected with a pMC-Cre expression plasmid to delete the neo cassette. These ES cells were injected into C57BL/6J blastocysts and the resulting chimeric males were bred to C57BL/6J females. These mice were maintained on a mixed background. Upon arrival at The Jackson Laboratory, mice were bred to C57BL/6J (Stock No. 000664) for at least one generation to establish the colony.

Allele

Symbol: Abcg2^{tm3.1(cre/ERT2)Bsor}
Name: targeted mutation 3.1, Brian P Sorrentino
MGI accession ID: MGI:5444690
Generation method: Targeted
Attributes: Recombinase-expressing; Inducible; Hypomorph
Marker symbol: Abcg2
Marker name: ATP binding cassette subfamily G member 2 (Junior blood group)
Chromosome: 6
Strain of origin: 129X1/SvJ
Expressed genes: cre/ERT2,Cre recombinase and estrogen receptor 1 (human) fusion gene,
Site of expression: Cre expression is seen in hematopoietic cells of renal proximal tubules, testicular germ cells, small intestine, liver, and cardiac and skeletal muscle. Reduced expression is seen in the kidney and liver.
Molecular note: A targeting vector was generated with a neomycin resistance cassette, IRES-cre/ERT2 and polyadenylation sequences. The construct was electroporated into ES cells, and homologous recombination inserted the neo-IRES-cre/ERT2-pA sequence into exon 16 of the Abcg2 gene. Correctly targeted ES cells were transiently transfected with a pMC-cre plasmid to excise the nomycin cassette. The ES cells were injected into blastocysts to generate chimeric animals which were used to establish germline transmission. The allele is stated to be hypomorphic for Abcg2 protein expression in the kidney (slight reduction) and liver (greater reduction) determined by Western blot, in homozygous animals.