These knock-in mice (also referred to as Oct4-MerCreMer mice) express a tamoxifen-inducible cre recombinase from the endogenous promoter/enhancer elements of the Pou5f1 gene. When induced, cre activity is observed in Pou5f1 expressing cells in embryos and in Induced pluripotent stem (iPS) cells derived from these mice. These mice may be useful for generating conditional mutations for studying lineage tracing, and production of cell lines and targeted knock-out mutations.
Yoav Segal, University of Minnesota
Genetic Background | Generation |
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|
Allele Type | Gene Symbol | Gene Name |
---|---|---|
Targeted (Recombinase-expressing, Inducible) | Pou5f1 | POU domain, class 5, transcription factor 1 |
These targeted mutation mice have a tamoxifen inducible Cre-mediated recombination system ("MerCreMer") driven by the endogenous Pou5f1 (POU domain, class 5, transcription factor 1) promoter. Mice that are heterozygous for the targeted mutation are viable, fertile, normal in size and do not display any gross physical or behavioral abnormalities. The viability and fertility of homozygotes is not yet known. Inducible Cre mediated recombination occurs in Pou5f1 (Oct4) expressing cells in embryos and in iPS cells derived from these mice. Of note, this double fusion protein has substantially greater Cre recombinase activity with less promiscuity compared with a single CreMer fusion protein. As the cre is flanked on each end with a mutated murine estrogen receptor ligand binding domain (amino acids 281-599, G525R); Cre expression is tamoxifen inducible yet estrogen insensitive. These Oct4-Inducible Cre mice may be useful for generating conditional mutations for studying lineage tracing, and production of cell lines and targeted mutations (knockouts).
The cre/Esr1* fusion protein consists of Cre recombinase fused to a G525R mutant form of the mouse 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/Esr1* 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.
A targeting vector containing an FRT-site flanked NEO cassette and IRES-MerCreMer sequence was inserted in the 3' UTR of Oct4/Pou5f1 locus. The construct was electroporated into C57BL/6 derived embryonic stem (ES) cells from inGenious Targeting Laboratory. Correctly targeted ES cells were injected into recipient B6(Cg)-Tyrc-2J/J or BALB/c blastocysts. The resulting chimeric animals were crossed to B6.Cg-Tg(ACTFLPe)9205Dym/J
(Stock No. 005703) mice to remove the FRT site flanked selection cassette. The mice were then backcrossed to C57BL/6NHsd for 8 generations. Upon arrival at The Jackson Laboratory, the mice were crossed to C57BL/6NJ (Stock No. 005304) at least once to establish the colony.
Expressed Gene | cre/Esr1, Cre recombinase and estrogen receptor 1 fusion gene, |
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Site of Expression | Inducible Cre mediated recombination occurs in Pou5f1 expressing cells in embryos and in induced pluripotent stem cells derived from these mice. |
Allele Name | targeted mutation 1.1, Yoav Segal |
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Allele Type | Targeted (Recombinase-expressing, Inducible) |
Allele Synonym(s) | Oct4-MerCreMer |
Gene Symbol and Name | Pou5f1, POU domain, class 5, transcription factor 1 |
Gene Synonym(s) | |
Expressed Gene | cre/Esr1, Cre recombinase and estrogen receptor 1 fusion gene, |
Site of Expression | Inducible Cre mediated recombination occurs in Pou5f1 expressing cells in embryos and in induced pluripotent stem cells derived from these mice. |
Strain of Origin | C57BL/6 |
Chromosome | 17 |
Molecular Note | A targeting vector containing an FRT-site flanked NEO cassette and IRES-MerCreMer sequence was inserted in the 3' UTR of Oct4/Pou5f1 locus. The construct was electroporated into C57BL/6 derived embryonic stem (ES) cells from inGenious Targeting Laboratory. Correctly targeted ES cells were injected into recipient B6(Cg)-Tyrc-2J/J or BALB/c blastocysts. The resulting chimeric animals were crossed to B6.Cg-Tg(ACTFLPe)9205Dym/J mice to remove the FRT site flanked selection cassette. |
When maintaining a live colony, heterozygous mice may be bred with wildtype mice from the colony or with C57BL/6NJ inbred mice (Stock No. 005304). The viability and fertility of homozygotes is not yet known.
When using the Oct4-MerCreMer mouse strain in a publication, please cite the originating article(s) and include JAX stock #016829 in your Materials and Methods section.
Facility Barrier Level Descriptions
Service/Product | Description | Price |
---|---|---|
Heterozygous or wildtype for Pou5f1<tm1.1(cre/Esr1*)Yseg> |
Frozen Mouse Embryo | B6(SJL)-Pou5f1<tm1.1(cre/Esr1*)Yseg>/J | $2595.00 |
Frozen Mouse Embryo | B6(SJL)-Pou5f1<tm1.1(cre/Esr1*)Yseg>/J | $2595.00 |
Frozen Mouse Embryo | B6(SJL)-Pou5f1<tm1.1(cre/Esr1*)Yseg>/J | $3373.50 |
Frozen Mouse Embryo | B6(SJL)-Pou5f1<tm1.1(cre/Esr1*)Yseg>/J | $3373.50 |
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The Jackson Laboratory has rigorous genetic quality control and mutant gene genotyping programs to ensure the genetic background of JAX® Mice strains as well as the genotypes of strains with identified molecular mutations. JAX® Mice strains are only made available to researchers after meeting our standards. However, the phenotype of each strain may not be fully characterized and/or captured in the strain data sheets. Therefore, we cannot guarantee a strain's phenotype will meet all expectations. To ensure that JAX® Mice will meet the needs of individual research projects or when requesting a strain that is new to your research, we suggest ordering and performing tests on a small number of mice to determine suitability for your particular project. We do not guarantee breeding performance and therefore suggest that investigators order more than one breeding pair to avoid delays in their research.
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