C57BL/6N-Tg(Tg-cre/ERT2)1Kero/J

Stock number: 030676
Product name: TgCreER^T2
Research areas: Endocrine Deficiency Research, Internal/Organ Research, Research Tools

Description

TgCreER^T2 mice express creER^T2 directed by thyroglobulin (Tg) promoter on a PAC transgene. These mice may be useful for thyroid specific gene deletion.

Detailed description

TgCreER^T2 mice express creER^T2 fusion gene (a Cre recombinase fused to a human estrogen receptor ligand binding domain) directed by murine thyroglobulin (Tg) promoter/enhancer regions on a PAC transgene. Mice homozygous for the transgene are viable and fertile. TG is a glycoprotein homodimer expressed specifically in the thyroid. It is a precursor of the iodinated thyroid hormones thyroxine (T4) and triiodothyronine (T3). Restricted to the cytoplasm, creER^T2 can only gain access to the nuclear compartment after exposure to tamoxifen. When TgCreER^T2 are bred with mice containing loxP-flanked sequence, tamoxifen-inducible cre-mediated recombination will result in deletion of the floxed sequences in the cre-expressing cells of the offspring. Cre-mediated recombination is evident in nearly all thyroid follicular cells.

Development

P1 artificial chromosome (PAC) library RPCI21 was used to obtain a 100-kb PAC containing the entire mouse thyroglobulin (Tg) gene. This PAC was modified to replace the start codon of Tg with a creER^T2 fusion gene (a Cre recombinase fused to a human estrogen receptor ligand binding domain) followed by a bovine growth hormone polyadenylation signal and a frt-flanked ampicillin selection cassette. Following Flp-mediated removal of the ampicillin cassette, the PAC was microinjected into fertilized C57BL/6NCrl oocytes. TgCreER^T2 mice were maintained by breeding transgenic mice with C57BL/6NCrl inbred mice for at least ten generations. Upon arrival at The Jackson Laboratory, sperm was cryopreserved. To establish our live colony, an aliquot of frozen sperm was used to fertilize C57BL/6NJ oocytes (Stock No. 005304).

Allele

Symbol: Tg(Tg-cre/ERT2)1Kero
Name: transgene insertion 1, Jukka Kero
MGI accession ID: MGI:5575412
Generation method: Transgenic
Attributes: Recombinase-expressing; Inducible
Synonyms: TgCreER^T2
Marker symbol: Tg(Tg-cre/ERT2)1Kero
Marker name: transgene insertion 1, Jukka Kero
Chromosome: UN
Strain of origin: C57BL/6NCrl
Expressed genes: cre/ERT2,Cre recombinase and estrogen receptor 1 (human) fusion gene,
Site of expression: Thyroid gland.
Molecular note: RedE/RedT-recombination was used to insert a cassette encoding tamoxifen-inducible cre (cre/ERT2), an frt-flanked ampicillin selection marker, and the bovine growth hormone polyadenylation signal at the ATG start codon of the thyroglobulin (Tg) gene in a P1 artificial chromosome (PAC). Following recombination, flp-mediated deletion of the ampicillin marker was performed. The verified construct was linearized, then used for injection of C57BL/6 fertilized oocytes. 5/35 pups tested positive for cre by PCR. Founders were tested for specificity and inducibility of cre recombinase by breeding to lacZ reporter mice and treating double mutants with tamoxifen. 4 founders showed cre activity only in the thyroid gland, and one line with strong and homogenous cre activity was chosen for detailed analyses.