B6.Cg-Tg(Vil1-cre/ERT2)23Syr/J

Stock number: 020282
Product name: villin:creERT2 , villin-creERT2 , vil:creERT2 , vil-creERT2 , vill:creERT2 , vill-creERT2
Research areas: Cancer Research, Endocrine Deficiency Research, Internal/Organ Research, Research Tools

Description

vil-Cre-ER^T2 mice carry a transgene with tamoxifen inducible Cre recombinase under the control of the 9 kb mouse Vil1, villin 1, promoter, and may be useful for generating specific targeted mutants for studies of the crypt-villus axis of the intestinal epithelium.

Detailed description

These vil-Cre-ER^T2 transgenic mice express a tamoxifen inducible Cre recombinase driven by the 9-kb mouse Vil1, villin 1, 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. Tamoxifen administration induces Cre recombination in the intestinal epithelia of the duodenum, jejunum, ileum, and proximal and distal colon. No recombination is detected in brain, lung or heart. Inducible Cre recombinase activity is detected in the visceral endoderm of E9 embryos and the intestinal epithelium in E12.5 embryos. Southern blot analysis of founder line 23 (Fo23) revealed a single copy insertion of the transgene. The Donating Investigator has not attempted to make this strain homozygous. Hemizygotes are viable and fertile. Homozygous viability/fertility has not been tested (January 2019).

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 the cre/ERT2, Cre recombinase and estrogen receptor 1 (human) fusion gene, followed by an SV40 polyadenylation signal, under the control of the 9 kb mouse Vil1, villin 1, gene promoter, was injected into fertilized B6D2 (C57BL/6 x DBA/2) mouse eggs. Founder line 23 (Fo23) was subsequently established. Southern blot analysis revealed a single copy insertion of the transgene. The mice were then backcrossed to C57BL/6NCrl for 10 generations by the donating laboratory (see SNP note below). During backcrossing, the Y chromosome may not have been fixed to the C57BL/6NCrl genetic background. Cryopreserved embryos were sent to The Jackson Laboratory Repository. To establish our live colony, the embryos were recovered and bred to C57BL/6NJ (Stock No. 005304) mice. Sperm was later cryopreserved.

In 2019 a 48 SNP (single nucleotide polymorphism) panel analysis, with 43 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 mice recovered from the frozen embryos sent to The Jackson Laboratory Repository. While the 43 markers throughout the genome suggested a C57BL/6 genetic background, all 5 markers that determine C57BL/6J from C57BL/6N were found to be segregating, including the rd8 recessive mutation associated with retinal degeneration on Chromosome 1 within the Crb1 locus. These data suggest the embryos sent to The Jackson Laboratory Repository were on a mixed C57BL/6J ; C57BL/6N genetic background.

Allele

Symbol: Tg(Vil1-cre/ERT2)23Syr
Name: transgene insertion 23, Sylvie Robine
MGI accession ID: MGI:3053826
Generation method: Transgenic
Attributes: Recombinase-expressing; Inducible
Marker symbol: Tg(Vil1-cre/ERT2)23Syr
Marker name: transgene insertion 23, Sylvie Robine
Chromosome: UN
Strain of origin: (C57BL/6 x DBA/2)
Molecular note: A 9 kb segment of the regulatory region of the mouse Vil gene drives expression of cre recombinase fused to a mutated ligand-binding domain of the human estrogen receptor. Cre recombination is inducible with tamoxifen treatment in epithelial cells all along the crypt-villus axis and in undifferentiated progenitor cells in the crypt region. This is a representative record for the two lines generated (Fo23 and Fo24) that have the same inducible expression pattern. Only 1 copy of the transgene is integrated into these lines.