B6;CBA-Tg(Upk2-icre/ERT2)1Ccc/J

Stock number: 024768
Product name: TgUICBAC
Research areas: Cancer Research, Research Tools

Description

This TgUICBAC transgenic strain carries a transgene with tamoxifen inducible Cre recombinase. These mice may have applications in studies requiring conditional gene manipulation in the urothelium.

Detailed description

These transgenic mice express a tamoxifen inducible Cre recombinase driven by the mouse Upk2 , uroplakin 2, promoter. When crossed with a strain containing a loxP site flanked sequence of interest, the offspring are useful for generating tamoxifen-induced, Cre-mediated targeted deletions specific to the urothelium. Tamoxifen administration induces Cre recombination in the urothelium Upk2 expressing cells of bladder, ureter, and the renal pelvis of the kidney. No inducible Cre recombinase activity was detected in intestine, lung, heart, liver, spleen, testis, prostate, ovary, uterus, skin, thymus, cerebellum, cerebrum, or stomach. Homozygous mutant mice are viable and fertile.

The Cre-ERT2 fusion protein (Cre-ERT2) consists of Cre recombinase fused to a triple mutant form of the human estrogen receptor; which does not bind its natural ligand (17?-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 bMQ-343M5 mouse bacterial artificial chromosome (BAC) containing the entire Upk2 gene (and parts of the Foxr1 and Cxcr5 genes, and the Bcl9l gene) was modified by inserting iCre-ERT2 fusion protein coding sequence followed by a polyA signal into the ATG initiation start site of the Upk2 gene. A transgenic construct containing containing sequence encoding iCre-ERT2 fusion protein under the control of the mouse mouse Upk2, uroplakin 2, promoter, was injected into fertilized B6CBA/F1 mouse eggs. The donating investigator reported that the mice were then backcrossed to the C57BL/6J background for 10 generations (see SNP note below). During backcrossing, the Y chromosome may not have been fixed to the C57BL/6J genetic background. Upon arrival at The Jackson Laboratory, the mice were crossed to C57BL/6J (Stock No. 000664) at least once to establish the colony.

A 32 SNP (single nucleotide polymorphism) panel analysis, with 27 markers covering all 19 chromosomes and the X chromosome, as well as 5 markers that distinguish between the C57BL/6J and C57BL/6N substrains, was performed on the rederived living colony at The Jackson Laboratory Repository. 4 Markers were still segregating with CBA, suggesting an incomplete backcross.

Allele

Symbol: Tg(Upk2-icre/ERT2)1Ccc
Name: transgene insertion 1, Carlos Cordon-Cardo
MGI accession ID: MGI:5568245
Generation method: Transgenic
Attributes: Recombinase-expressing; Inducible
Marker symbol: Tg(Upk2-icre/ERT2)1Ccc
Marker name: transgene insertion 1, Carlos Cordon-Cardo
Chromosome: UN
Strain of origin: (C57BL/6 x CBA)F1
Expressed genes: cre/ERT2,Cre recombinase and estrogen receptor 1 (human) fusion gene,
Site of expression: When these mice are crossed with a strain containing a loxP site flanked sequence of interest, tamoxifen administration in the offspring induces Cre recombination in the urothelium Upk2 expressing cells of bladder, ureter, and the renal pelvis of the kidney.
Molecular note: The bMQ-343M5 mouse bacterial artificial chromosome (BAC) containing the entire Upk2 gene (and parts of the Foxr1 and Cxcr5 genes, and the Bcl9l gene) was modified by inserting the icre/ERT2 fusion protein-coding sequence followed by a polyA signal into the ATG initiation start site of the Upk2 gene. The transgenic construct was injected into fertilized C57BL/6 x CBA)F1 mouse eggs. Two founders were obtained (#1 having 2 copies of the transgene and #5 with 4 copies). Only #1 was able to produce offspring, and this line was used for further analyses.