B6N.129S6-Bhlha15^tm1Skz/J

Stock number: 030394
Product name: Mist1^nLacZKO
Research areas: Metabolism Research

Description

Mist1^nLacZKO mice have a β-gal gene and a neo cassette replacing the entire coding region of the basic helix-loop-helix family, member a15 (Bhlha15) gene, abolishing gene expression. These mice may be useful for studying chronic pancreatic injury and pancreatitis.

 

Detailed description

Mist1^nLacZKO mice have a nuclear-localized β-gal gene (nLacZ) and a neo cassette replacing the entire coding region of the basic helix-loop-helix family, member a15 (Bhlha15) gene, abolishing gene expression. 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. Homozygotes are viable and fertile. Beginning at E10.5, β-gal is seen in the primitive foregut, caudal, and medial to the forelimb bud, and the pancreatic bud. By E12.5, β-gal staining is seen in the two pancreatic buds in the lower part of the foregut. Staining in older embryos stains pancreatic acinar cells. At 12 months of age, focal lesions are evident in exocrine tissue, which progress and cause a significant decrease in the amount of acinar tissue along with large accumulations of other cell types. These mice show extensive disorganization of exocrine tissue and intracellular enzyme activation. The endocrine component of the pancreas appears unaffected in Mist1^KO mice, and they contain normal levels of insulin and glucagon, and blood serum glucose levels are unaffected. Despite alterations in seminal fluid composition, male reproductive function and fertility are normal.

Development

A targeting vector was designed to replace the entire coding region of the basic helix-loop-helix family, member a15 (Bhlha15) gene with a nuclear-localized β-galactosidase gene (nLacZ) fused to a neomycin resistance (neo) cassette in reverse orientation to the gene. The construct was electroporated into 129S6/SvEvTac-derived TL1 embryonic stem (ES) cells. Correctly targeted ES cells were injected into C57BL/6 blastocysts and the resulting chimeric males were bred to C57BL/6 females. These Mist1^nLacZKO mice were backcrossed to C57BL/6NHsd mice for at least 10 generations. Upon arrival at The Jackson Laboratory embryos were recovered to establish the colony.

Allele

Symbol: Bhlha15^tm1Skz
Name: targeted mutation 1, Stephen F Konieczny
MGI accession ID: MGI:2182768
Generation method: Targeted
Attributes: Reporter; Null/Knockout
Synonyms: Bhlhb8^-; Bhlhb8^lacZ; Mist1^-; Mist1^KO; Mist1^LacZ
Marker symbol: Bhlha15
Marker name: basic helix-loop-helix family, member a15
Marker synonyms: 1810009C13Rik; bHlH; Bhlhb8; Mist1
Chromosome: 5
Strain of origin: 129S6/SvEvTac
Expressed genes: lacZ,beta-galactosidase,E. coli
Site of expression: Pancreatic acinar cells but not in duct, islet, or centroacinar cells.
Molecular note: The entire coding region of the gene was replaced with a lacZ-neo cassette via homologous recombination. Absence of gene expression in homozygous mutant animals was confirmed by immunohistochemical analysis, Western blot and RT-PCR.