STOCK Tg(IVL-cre/ERT2)1Blpn/J

Stock number: 019380
Product name: Inv-CreERT2
Research areas: Developmental Biology Research, Research Tools

Description

The INV-CreERT2 allele expresses a CreERT2 fusion protein from the human involucrin Ivl promoter. They may have applications studies related to epidermal lineage tracing.

Detailed description

Mice hemizygous for the INV-CreERT2 transgene are viable and fertile, with expression of CreER^T2 fusion protein directed to the epidermis by the human involucrin (Ivl) promoter. Specifically, the donating investigator reports that the INV-CreERT2 transgene directs reporter gene expression in suprabasal and basal committed cell populations. Cre-ERT2 fusion gene activity is inducible; observed at high levels following tamoxifen administration. When Inv-CreERT2 transgenic mice are bred with mice containing loxP-flanked sequences, tamoxifen-inducible Cre-mediated recombination will result in deletion of the floxed sequences in the INV-expressing cells of the double mutant offspring.

For example, when bred to Gt(ROSA)26Sor^tm1(EYFP)Cos mice (see Stock No. 006148) containing a floxed-STOP cassette followed by a yellow fluorescent protein (YFP), tamoxifen administration results in removal of the STOP cassette and subsequent YFP expression in INV-expressing cells of double mutant offspring. YFP fluorescence is seen in suprabasal cells, and some basal cells, of the interfollicular epidermis of the back skin, tail skin, and the lips. Cells were also labeled in the companion layer of the hair follicle, as well as suprabasal cells of the infundibulum.

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 INV-CreERT2 transgene was designed with the human involucrin (Ivl) promoter driving expression of a CreER^T2 fusion gene (Cre-ER^T2; Cre recombinase fused to a G400V/M543A/L544A triple mutation of the human estrogen receptor ligand binding domain.) The construct was microinjected into C57BL/6 fertilized oocytes, and founder mice were bred to CD1 outbred mice for at least 5 generations to establish a colony. Upon arrival at The Jackson Laboratory, mice were bred to C57BL/6J inbred mice (Stock No. 000664) for at least one generation.

Allele

Symbol: Tg(IVL-cre/ERT2)1Blpn
Name: transgene insertion 1, Cedric Blanpain
MGI accession ID: MGI:4999984
Generation method: Transgenic
Attributes: Recombinase-expressing; Inducible
Marker symbol: Tg(IVL-cre/ERT2)1Blpn
Marker name: transgene insertion 1, Cedric Blanpain
Chromosome: UN
Strain of origin: C57BL/6
Expressed genes: cre/ERT2,Cre recombinase and estrogen receptor 1 (human) fusion gene,
Site of expression: This transgene directs reporter gene expression in suprabasal and basal committed cell populations when bred with mice containing loxP-flanked sequences.
Molecular note: A cre/ERT2 fragment was cloned into a vector containing the human involucrin (IVL) promoter, the SV40 intron, and the SV40 polyA signal. The transgenic construct was microinjected into fertilized oocytes, and three founders were generated. Expression profiles were screened with crosses to ROSA-YFP reporter mice.