STOCK Gt(ROSA)26Sor^{tm1.1(rtTA,EGFP)Nagy} Hprt^{tm1(tetO-Dkk1)Spdl} Tg(TCF/Lef1-lacZ)34Efu/J

Stock number: 024746
Strain synonyms: Rosa26-rtTa;Tet-Dkk1;TOPGAL
Research areas: Research Tools

Description

Widespread expression of the Dkk1 in this Hprt (hypoxanthine guanine phosphoribosyl transferase) mutant strain is regulated by a tetracycline operator (tetO), and activation of the Wnt signaling pathway can be monitored via the TOPGAL transgene. This strain may be useful in studies of the Wnt signaling pathway.

Detailed description

The Dkk1 gene encodes for Dickkopf1, which is a canonical Wnt/Beta-catenin inhibitor. These mice carry a knock in allele containing the Dkk1 gene under the control of the tetO, tetracycline-responsive regulatory element, inserted into the endogenous Hprt locus on the X chromosome; the widespread expressing Gt(ROSA)26Sor^{tm1.1(rtTA,EGFP)Nagy} allele and the TOPGAL, Tg(TCF/Lef1-lacZ)34Efu transgene. Widespread expression of the the Dkk1 gene in all tissues is inducible with Doxycycline. The TOPGAL transgene acts as a Beta-galactosidase reporter for Wnt/Beta-catenin signaling activation. Females heterozygous/males hemizygous for the Hprt^{tm1(tetO-Dkk1)Spdl} (which is X-linked), homozygous for the Gt(ROSA)26Sor^{tm1.1(rtTA,EGFP)Nagy} allele and hemizygous for the Tg(TCF/Lef1-lacZ)34Efu transgene are viable and fertile.

Development

A targeting vector containing the Tet-Dkk1 cassette (Dkk1 gene under the control of the tetO, tetracycline-responsive regulatory element) was inserted into the endogenous Hprt locus on the X chromosome. The construct was electroporated into mixed C57BL/6 and 129 derived BPES embryonic stem (ES) cells. Correctly targeted ES cells were injected into blastocysts. The resulting chimeric animals were tested for germline The mice were crossed to Swiss Webster mice and several other mutant lines. The mice were crossed with TOPGAL mice carrying the Tg(TCF/Lef1-lacZ)34Efu transgene, as well as mice carrying the Gt(ROSA)26Sor^{tm1(rtTA,EGFP)Nagy} allele. The mice were then crossed to CMV-cre mice expressing Cre recombinase in all tissues (Stock No. 003475) to remove the floxed STOP cassette in the Gt(ROSA)26Sor^{tm1(rtTA,EGFP)Nagy} allele, resulting in the generation of the Gt(ROSA)26Sor^{tm1.1(rtTA,EGFP)Nagy} allele. The mice were crossed to Swiss Webster mice and no longer carry the Tg(CMV-cre)1Cgn transgene. Upon arrival at The Jackson Laboratory, the mice were crossed to C57BL/6J (Stock No. 000664) at least once to establish the colony and breed out any other mutant alleles.

Allele

Symbol: Tg(TCF/Lef1-lacZ)34Efu
Name: transgene insertion 34, Elaine Fuchs
MGI accession ID: MGI:3057160
Generation method: Transgenic
Attributes: Reporter
Marker symbol: Tg(TCF/Lef1-lacZ)34Efu
Marker name: transgene insertion 34, Elaine Fuchs
Chromosome: UN
Strain of origin: Not Specified
Expressed genes: lacZ,beta-galactosidase,E. coli
Site of expression: lacZ expression occurs during early embryonic development in a subset of pluripotent embryonic basel cells of the epithelium and dermis of developing hair follicles. lacZ expression disappears during formation of hair germ and then reappears at E16.5 in hair follicles until 18 days after birth.
Molecular note: The transgene contains the lacZ gene under the control of a promoter consisting of three consensus lymphoid enhancer binding factor 1/transcription factor 3 (LEF/TCF)-binding motifs upstream of a minimal Fos promoter. This allele is responsive to canonical Wnt/beta-catenin signal transduction.
General note: Homozygous transgenic mice are viable, fertile, normal in size, and do not display any gross physical or behavioral abnormalities.

Transgenic mice express beta-galactosidase in the presence of the lymphoid enhancer binding factor 1/transcription factor 3 (LEF1/TCF3) mediated signaling pathway and activated Beta-catenin (CATNB).

Transgenic mice display Beta-galactosidase activity during early embryonic development in a subset of pluripotent embryonic basal cells of the epithelium and dermis of developing hair follicles. Beta-galactosidase activity is not detected in the next stage of hair follicle development, formation of hair germs. At E16.5, transgene activity reappears in hair follicles and is detectable until 18 days after birth.

Allele

Symbol: Gt(ROSA)26Sor^{tm1.1(rtTA,EGFP)Nagy}
Name: targeted mutation 1.1, Andras Nagy
MGI accession ID: MGI:5286599
Generation method: Targeted
Attributes: Reporter; Transactivator
Marker symbol: Gt(ROSA)26Sor
Marker name: gene trap ROSA 26, Philippe Soriano
Chromosome: 6
Strain of origin: (129X1/SvJ x 129S1/Sv)F1-Kitl⁺
Expressed genes: GFP,Green Fluorescent Protein,
Site of expression: Widespread reverse tetracycline transactivator (rtTA)-expression.
Molecular note: A targeting vector containing a floxed Pgk-neo-pA cassette and a rtTA-IRES-EGFP-pA cassette was inserted into intron 1 of the locus. Cre-mediated recombination removed the floxed neo cassette allowing the ROSA26 promoter to drive expression of rtTA and EGFP. Presence of doxycycline results in the formation of an active transcriptional activator and the activation of the responder transgene.

Allele

Symbol: Hprt^{tm1(tetO-Dkk1)Spdl}
Name: targeted mutation 1, Stijn De Langhe
MGI accession ID: MGI:5581839
Generation method: Targeted
Attributes: Inducible; Inserted expressed sequence
Marker symbol: Hprt
Marker name: hypoxanthine guanine phosphoribosyl transferase
Chromosome: X
Strain of origin: (129-Hprt^b-m3 x C57BL/6)F1
Expressed genes: Dkk1,dickkopf WNT signaling pathway inhibitor 1,mouse, laboratory
Site of expression: Expression of Dkk1 is widespread under the control of tetO.
Molecular note: A targeting vector containing the tetracycline responsive promoter driving inducible expression of Dkk1 was inserted into the endogenous Hprt locus on the X chromosome.