B6.Cg-Tg(KRT14-cre/ERT2)1Ipc/MtzJ

Stock number: 038390
Product name: K14-Cre-ER^T2
Strain synonyms: B6.Cg-Tg(KRT14-cre/ERT2)1Ipc/AkinJ
Research areas: Cancer Research, Dermatology Research, Developmental Biology Research, Research Tools

Description

K14-Cre-ER^T2 mice express a tamoxifen-inducible Cre recombinase/ER^T2 fusion under the control of the human keratin K14 (KRT14) promoter/enhancer. Cre recombinase activity is observed in the basal layer of stratified squamous epithelia. This strain may be useful tool in studies of the epidermis.

Detailed description

K14-Cre-ER^T2 mice express Cre/ER^T2 under control of the human keratin K14 (KRT14) promoter/enhancer regions. KRT14 directs expression of the tamoxifen inducible Cre recombinase to the basal layer of stratified squamous epithelia as well as the tongue, esophagus, and stomach. When transgenic mice are bred with mice containing loxP-flanked (floxed) sequences, tamoxifen-inducible cre-mediated recombination will result in deletion of floxed sequences in KRT14-expressing cells in the offspring. Cre/ER^T2 provides a higher efficiency of recombination than Cre/ER and can be induced by a milder tamoxifen treatment (0.1 mg for 5 days). Hemizygous and homozygous mice are viable and fertile with no reported phenotype abnormalities.

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 (17β-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 K14-Cre-ER^T2 transgenic construct contains the human keratin K14 promoter/enhancer fragment (2 kb) directing expression of cre/ERT2 followed by SV40-polyA sequence. The construct was microinjected into the pronuclei of fertilized (C57BL/6 x SJL)F1 oocytes. Founder line 1 was established. The transgene insertion site and copy number are unknown. Mice were backcrossed to C57BL/6J for 10 generations and then frozen as sperm in 2017. In 2024, the donating investigator arranged to have frozen sperm sent to The Jackson Laboratory. To establish our live colony, an aliquot of frozen sperm was used to fertilize C57BL/6J oocytes (Stock No. 000664).

Allele

Symbol: Tg(KRT14-cre/ERT2)1Ipc
Name: transgene insertion 1, I Pierre Chambon
MGI accession ID: MGI:2177426
Generation method: Transgenic
Attributes: Recombinase-expressing; Inducible
Synonyms: K14-Cre:ER; K14-Cre-ER^T2
Marker symbol: Tg(KRT14-cre/ERT2)1Ipc
Marker name: transgene insertion 1, I Pierre Chambon
Marker synonyms: K14-Cre:ER; K14-Cre-ER^T2
Chromosome: UN
Strain of origin: (C57BL/6 x SJL)F1
Molecular note: This transgene expresses a tamoxifen-inducible form of cre recombinase in the epidermis, tongue, esophagus, stomach, and other epithelial tissues.