B6.Cg-Tg(Prrx1-cre/ERT2,-EGFP)1Smkm/J

Stock number: 029211
Product name: Prx1CreER-GFP
Research areas: Developmental Biology Research, Research Tools

Description

This Prx1CreER-GFP mutant mouse strain carries a transgene with tamoxifen inducible Cre recombinase and may be useful for generating osteochondro progenitor cell specific targeted mutants for studies of cartilage and bone development, lineage fate mapping, and isolation of transgene expressing periosteal cells.

Detailed description

These transgenic mice express tamoxifen-inducible Cre recombinase, cre/ERT2, and enhanced green fluorescent protein (EGFP) under the control of the 2.4 kb mouse Prrx1, paired related homeobox 1, gene promoter. Transgene expression is detected in developing limbs by fluorescence, as early as E10.5, and in craniofacial areas and limbs by E17.5. Tamoxifen treatment of pregnant females when embryos are E9.0 results in recombination at E17.0 in chondrocytes and osteoblasts in the developing limb. Tamoxifen treatment of transgenic mice, postnatal day 19, results in recombination in the perichondrium and periosteum. Mice that are homozygous for the transgene are viable and fertile. The Donating Investigator reports there is no difference between the phenotype exhibited by homozygotes compared to hemizygotes. During backcrossing, the Y chromosome may not have been fixed to the C57BL/6 genetic background.

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

A transgenic construct containing tamoxifen-inducible Cre recombinase, cre/ERT2, IRES sequence, enhanced green fluorescent protein (EGFP) cDNA, and SV40 polyadenylation signal sequence, under the control of the 2.4 kb mouse Prrx1, paired related homeobox 1, gene promoter, was injected into fertilized (C57BL6 X SJL)F2 mouse eggs. Founder line 1 was subsequently established. The mice were then backcrossed to C57BL/6 for 8 generations. During backcrossing, the Y chromosome may not have been fixed to the C57BL/6 genetic background. Upon arrival, sperm was cryopreserved. To establish our live colony, an aliquot of frozen sperm was used to fertilize C57BL/6J oocytes (Stock No. 000664).

Allele

Symbol: Tg(Prrx1-cre/ERT2,-EGFP)1Smkm
Name: transgene insertion 1, Shunichi Murakami
MGI accession ID: MGI:4355342
Generation method: Transgenic
Attributes: Recombinase-expressing; Reporter; Inducible
Marker symbol: Tg(Prrx1-cre/ERT2,-EGFP)1Smkm
Marker name: transgene insertion 1, Shunichi Murakami
Chromosome: UN
Strain of origin: (C57BL/6 x SJL)F2
Expressed genes: cre/ERT2,Cre recombinase and estrogen receptor 1 (human) fusion gene,; GFP,Green Fluorescent Protein,
Site of expression: Transgene expression is detected in developing limbs by fluorescence, as early as E10.5, and in craniofacial areas and limbs by E17.5.
Molecular note: The cre/ER^T2 cDNA was cloned downstream of a 2.4 kb Prrx1 promoter. cDNA encoding an IRES-EGFP was inserted downstream of the cre/ER^T2 sequence. This construct was injected into fertilized oocytes and 3 founders that expressed the transgene in the limbs were identified. Crosses to Rosa26-lacZ reporter mice identified two lines which had intense X-gal staining upon induction with tamoxifen. One line was chosen for further analysis.