B6;129-Bhlha15^tm4Skz/J

Stock number: 029231
Product name: Mist1^lox
Research areas: Endocrine Deficiency Research, Research Tools

Description

Mist1^lox/lox mice possess loxP sites flanking the entire coding region of the basic helix-loop-helix family, member a15 (Bhlha15) gene. This strain may be useful for studying pancreatic acinar cell death during acute pancreatitis.

 

Detailed description

Mist1^lox/lox floxed mice possess loxP sites flanking exon 2, containing the entire coding region, of the basic helix-loop-helix family, member a15 (Bhlha15) gene. The MIST1 coding region was also engineered to contain an E. coli biotin ligase BirA biotin tag (BT) sequence (MASSLRQILDSQKMEWRSNAGGS) at the N-terminus of the protein where BirA can biotinylate the central lysine residue in the sequence. Additionally, the MIST1 coding region contains a MYC/6x His tag at the C-terminus that can be detected using anti-MYC. 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 locus 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 lactacting mammary aveolar cells. Mice that are homozygous for this allele are viable and fertile and continue to express the BT-MIST1-Myc/His protein. When these mutant mice are bred to mice that express Cre recombinase, resulting offspring will lack the entire coding region in cre-expressing tissues.

Development

A targeting vector was designed to insert loxP sites flanking exon 2, which contains the entire coding region of the basic helix-loop-helix family, member a15 (Bhlha15) gene. The MIST1 coding region was also engineered to contain an E. coli biotin ligase BirA biotin tag (BT) sequence (MASSLRQILDSQKMEWRSNAGGS) at the N-terminus of the protein where BirA can biotinylate the central lysine residue in the sequence. Additionally, the MIST1 coding region contains a MYC/6x His tag at the C-terminus that can be detected using anti-MYC. A frt-flanked neomycin resistance (neo) cassette was inserted downstream of the floxed sequence. Of note, the floxed region has been sequenced and appears to be derived from rat. The 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 resulting chimeric males were bred with C57BL/6NHsd females. The donating lab reported that the resulting offspring were bred to C57BL/6NHsd mice for at least 20 generations (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).

Of note, this strain arrived carrying the C57BL/6NHsd linked Dock2^m1Hsd spontaneous mutation. This allele has since been removed from the colony maintained at The Jackson Laboratory.

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 rederived living colony at The Jackson Laboratory Repository. Two of the 27 markers throughout the genome were segregating with 129, suggesting an incomplete backcross. Also, 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^tm4Skz
Name: targeted mutation 4, Stephen F Konieczny
MGI accession ID: MGI:5770104
Generation method: Targeted
Attributes: Conditional ready (e.g. floxed); No functional change
Synonyms: Mist1^lox
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⁺
Molecular note: A targeting vector was designed to insert a loxP sites flanking exon 2, containing the entire coding region of the basic helix-loop-helix family, member a15 (Bhlha15) gene. The MIST1 coding region was also engineered to contain an E. coli biotin ligase BirA biotin tag (BT) sequence (MASSLRQILDSQKMEWRSNAGGS) at the N-terminus of the protein where BirA can biotinylate the central lysine residue in the sequence. Additionally, the MIST1 coding region contains a MYC/6x His tag at the C-terminus that can be detected using anti-MYC. A frt-flanked neomycin resistance (neo) cassette was inserted downstream of the floxed sequence.