STOCK Polr2a^{tm1(cre/ERT2)Bbd}/J

Stock number: 017585
Research areas: Research Tools

Description

These RERT mutant mice express the inducible Cre-ERT2 from the endogenous Polr2a locus.

Detailed description

Mice that are homozygous for the targeted mutations are viable, fertile, normal in size and do not display any gross physical or behavioral abnormalities. These mutant mice express CreERT2 from the endogenous Polr2a locus. When these mice are bred with mice containing a loxP-flanked sequence of interest, tamoxifen-inducible, Cre-mediated recombination will result in deletion of the flanked sequences in Polr2a-expressing tissues

When bred to mice carrying the floxed E4f1^tm1.1Llca allele, the double mutant mice (Stock No. 017569) develop epidermal hyperplasia, epidermal cell loss and severe skin ulceration after topical applications of tamoxifen, and may be useful in studies of epidermal stem cells and skin homeostasis.

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

IRES-creERT2 was inserted between the termination codon and the polyadenylation signal of the Polr2a gene. This construct was electroporated into unspecified embryonic stem (ES) cells. Correctly targeted ES cells were injected into recipient blastocysts. The mice were maintained on a DBA background. The mice were then crossed to another targeted mutation strain on the B6.129S4 background. Upon arrival at The Jackson Laboratory, the double mutant mice were crossed to C57BL/6J (Stock No. 000664) at least once to separate the alleles and establish this colony of mice carrying only the Polr2a^{tm1(cre/ERT2)Bbd} targeted mutation.

Allele

Symbol: Polr2a^{tm1(cre/ERT2)Bbd}
Name: targeted mutation 1, Mariano Barbacid
MGI accession ID: MGI:3772332
Generation method: Targeted
Attributes: Recombinase-expressing; Inducible
Marker symbol: Polr2a
Marker name: polymerase (RNA) II (DNA directed) polypeptide A
Chromosome: 11
Strain of origin: Not Specified
Expressed genes: cre/ERT2,Cre recombinase and estrogen receptor 1 (human) fusion gene,
Site of expression: Topical applications of tamoxifen on bare skin result in deletion of the floxed sequences in the treated skin, with epidermal hyperplasia, epidermal cell loss and severe skin ulceration 1 to 2 weeks after application.
Molecular note: An IRES-cre/ERT2 cassette was knocked in between the termination codon and the polyadenylation signal to allow for biscistronic inducible expression of cre.