B6.129-Bhlha15^{tm3(cre/ERT2)Skz}/J

Stock number: 029228
Product name: Mist1^CreERT2
Research areas: Endocrine Deficiency Research, Research Tools

Description

The Mist1^CreERT2 knock-in/knock-out allele has a creER^T2 fusion gene replacing the entire Bhlha15 coding region. Mist1^CreERT2 mice may be useful for applications requiring tamoxifen-induced deletion of floxed sequences in pancreatic acinar cells.

Detailed description

Mist1^CreERT2 mice have a creER^T2 fusion gene (a Cre recombinase fused to a human estrogen receptor ligand binding domain) replacing the entire coding region of the basic helix-loop-helix family, member a15 (Bhlha15) gene. This allele is a knock-out with respect to the MIST1 protein.

MIST1 is a basic helix-loop-helix transcription factor that is expressed in pancreatic acinar cells but not in duct, islet, or centroacinar cells. The Mist1 gene is also expressed in most serous secretory cells including acinar cells of the salivary gland, chief cells of the stomach, paneth cells in the small intestine and in lactating mammary aveolar cells. Restricted to the cytoplasm, Cre-ER^T2 can only gain access to the nuclear compartment after exposure to tamoxifen. Homozygous mice are viable and fertile.

Mist1^CreERT2 homozygous mice are viable and fertile. These animals exhibit a number of defects associated with production and secretion of serous protein products as has been documented in a large number of publications. When these mice 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.

Development

A targeting construct was designed to replace the entire coding region, contained within exon 2, of the basic helix-loop-helix family, member a15 (Bhlha15) gene with a creER^T2 fusion gene (a Cre recombinase fused to a human estrogen receptor ligand binding domain) followed by a frt-flanked neomycin resistance (neo) cassette. This construct was electroporated into (129X1/SvJ x 129S1/Sv)F1-Kitl⁺-derived R1 embryonic stem (ES) cells. Correctly targeted ES cells were injected into blastocysts and the resulting chimeric mice were bred to C57BL/6NHsd mice for at least 20 generations by the donating lab (see SNP note below). Upon arrival, sperm was cryopreserved. To establish our live colony, an aliquot of frozen sperm was used to fertilize C57BL/6NJ oocytes (Stock No. 005304).

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. While the 27 markers throughout the genome suggested a C57BL/6 genetic background, 1 of 5 markers that determine C57BL/6J from C57BL/6N were found to be segregating. These data suggest the mice sent to The Jackson Laboratory Repository were on a mixed C57BL/6J ; C57BL/6N genetic background.

Allele

Symbol: Bhlha15^{tm3(cre/ERT2)Skz}
Name: targeted mutation 3, Stephen F Konieczny
MGI accession ID: MGI:3821734
Generation method: Targeted
Attributes: Recombinase-expressing; Inducible; Null/Knockout
Synonyms: Bhlha15^{tm3(cre/ESR1)Skz}; Mist1^creERT; Mist1^CreERT2; Mist1-CreERT2
Marker symbol: Bhlha15
Marker name: basic helix-loop-helix family, member a15
Marker synonyms: 1810009C13Rik; bHlH; Bhlhb8; Mist1
Chromosome: 5
Strain of origin: (129X1/SvJ x 129S1/Sv)F1-Kitl⁺
Expressed genes: cre/ERT2,Cre recombinase and estrogen receptor 1 (human) fusion gene,
Molecular note: The entire coding region was replaced with a cre-ESR1 (ERT2) fusion to allow for inducible cre expression in acinar cells.