B6.129S6-Serpinb1a^tm1.1Cben/J

Stock number: 034376
Product name: SerpinB1^-
Research areas: Hematological Research, Immunology, Inflammation and Autoimmunity Research

Description

SerpinB1^-/- mice lack exon 7 of the serine (or cysteine) peptidase inhibitor, clade B, member 1a (Serpinb1a) gene. These mice are useful when studying neutrophil development and homeostasis during acute immune responses.

Detailed description

SerpinB1^-/- mice lack exon 7 of the serine (or cysteine) peptidase inhibitor, clade B, member 1a (Serpinb1a) gene. Serpinb1, also known as monocyte neutrophil elastase (NE) inhibitor, is one of the most efficient inhibitors of NE, cathepsin G (CG), and proteinase-3 neutrophil-specific serine proteases. These proteases kill invading microbes, yet excess amounts play a central role in the pathology of inflammatory disease. SERPINB1 is widely expressed, and is expressed in all human bone marrow leukocytes, including stem and progenitor cells. Expression levels are particularly high in the cytoplasm of neutrophils. Mice that are homozygous for this allele are viable and fertile. SerpinB1^-/- mice have no abnormal phenotype until stressed or infected. They are hyper-susceptible to inflammation-inducing protocols and respond poorly to bacterial and viral infections. Hematopoietic cells are normal but there are abnormalities of cell counts. Specifically, after LPS administration, mice exhibit increases in cytokine and chemokine secretion, and IL1b and TNF secretion, with a 60% decrease in neutrophil number due to apoptosis.

Development

The SerpinB1^- targeting vector was designed to insert a loxP site upstream of exon 7 and a loxP-flanked hygromycin selection cassette downstream of exon 7 of the serine (or cysteine) peptidase inhibitor, clade B, member 1a (Serpinb1a) gene. The construct was electroporated into 129S6/SvEvTac-derived W4 embryonic stem (ES) cells. Correctly targeted ES cells were transiently transfected with a Cre expression plasmid to delete the hygro cassette and the floxed exon 7. Resulting ES cells were injected into recipient blastocysts and the resulting chimeric mice were bred with 129S6 mice. Subsequently these mice were backcrossed to C57BL/6J mice (Stock No. 000664) for at least 10 generations. The donating investigator states that the 129S6 genomic contributions have been reduced to less than 3-4 cM on either side of the SerpinB1 locus. Upon arrival at The Jackson Laboratory, sperm was cryopreserved. To establish our live colony, an aliquot of frozen sperm was used to fertilize C57BL/6J oocytes.

Allele

Symbol: Serpinb1a^tm1.1Cben
Name: targeted mutation 1, Charaf Benarafa
MGI accession ID: MGI:3761627
Generation method: Targeted
Attributes: Null/Knockout
Synonyms: serpinb1
Marker symbol: Serpinb1a
Marker name: serine (or cysteine) peptidase inhibitor, clade B, member 1a
Marker synonyms: 1190005M04Rik; EI; EIA; ELANH2; HEL57; HEL-S-27; LEI; M/NEI; MNEI; ovalbumin; PI2; PI-2; Serpinb1
Chromosome: 13
Strain of origin: 129S6/SvEvTac
Molecular note: A loxP site was introduced into intron 6 and a floxed Hyg-TK selection cassette into intron 7. Exon 7 and the selection cassette were removed by transient Cre expression, leaving a single loxP site behind. Western blot analysis on bone marrow neutrophils from homozygote mice indicated there was no expression of the wild-type allele.