B6;129S4-Gcg^{em1(cre/ERT2)Khk}/Mmjax

Stock number: 030346
Product name: Gcg-CreERT2
Research areas: Research Tools

Description

These Gcg-CreERT2 mice have Cre-ERT2 knocked into the 3' UTR region of the glucagon gene (Gcg). Inducible Cre expression is observed in pancreatic alpha cells and endocrine L cells.

Detailed description

An internal ribosome entry site (IRES)-CreERT2 fusion protein was inserted into the 3’ UTR upstream of the polyA sequence of the glucagon (Gcg) or preproglucagon gene. This knock-in allele expresses both preproglucagon and CreERT2 from the endogenous promoter. Gcg encodes a preproprotein that is a precursor for multiple bioactive peptides including the signal peptide and part of the N-terminal peptide, the remainder of the N-terminal peptide and glucagon (a pancreatic hormone), glucagon-like peptide 1 (GLP1) and glucagon-like peptide 2 (GLP2). Cre-ERT2 fusion gene activity is inducible and only observed following tamoxifen administration. Cre expression is observed in pancreatic alpha cells and endocrine L cells. Homozygotes males are viable and fertile. This strain may be useful for mediating inducible cre recombination in Gcg-expressing tissues.

The Cre-ERT2 fusion protein consists of Cre recombinase fused to a triple mutant form of the human estrogen receptor which does not bind its natural ligand (17ß-estradiol) at physiological concentrations but will bind the synthetic estrogen receptor ligands 4-hydroxytamoxifen (OHT or tamoxifen) and, with lesser sensitivity, ICI 182780. Restricted to the cytoplasm, Cre-ERT2 can only gain access to the nuclear compartment after exposure to tamoxifen. To counteract the mixed estrogen agonist effects of tamoxifen injections, which can result in late fetal abortions in pregnant mice, progesterone may be coadministered.

Development

The Gcg-Cre/ERT2 knock-in allele was created using homologous recombination (aided by targeted CRISPR/cas9 endonuclease activity) to insert an IRES-Cre/ERT2 sequence into the 3’ UTR of the glucagon (Gcg) locus on chromosome 2. The targeting vector, cas9 endonuclease and single guide RNA were co-electroporated into (C57BL/6x129S4/SvJae)F1-derived v6.5 embryonic stem (ES) cells. Correctly targeted ES cells were injected into blastocysts. The resulting animals were crossed to C57BL/6 and offspring were backcrossed to C57BL/6 for at least two generations. Upon arrival, mice were bred to C57BL/6J for at least 1 generation to establish the colony.

Allele

Symbol: Gcg^{em1(cre/ERT2)Khk}
Name: endonuclease-mediated mutation 1, Klaus H Kaestner
MGI accession ID: MGI:5825448
Generation method: Endonuclease-mediated
Attributes: Recombinase-expressing; Inducible; No functional change
Synonyms: Gcg-CreERT2
Marker symbol: Gcg
Marker name: glucagon
Marker synonyms: Glp1; GLP-1; GLP2; Glu; glucagon-like peptide I; GRPP; PPG
Chromosome: 2
Strain of origin: (C57BL/6 x 129S4/SvJae)F1
Expressed genes: cre/ERT2,Cre recombinase and estrogen receptor 1 (human) fusion gene,
Site of expression: Cre expression is observed in pancreatic alpha cells and endocrine L cells.
Molecular note: The allele is created using homologous recombination (aided by targeted CRISPR/cas9 endonuclease activity) to insert an IRES-Cre/ERT2 sequence into the 3' UTR of the gene. Cre expression is observed in pancreatic alpha cells and endocrine L cells.