B6.129S6-Aoah^tm1Rsm/J

Stock number: 028422
Product name: AOAH^-
Research areas: Immunology, Inflammation and Autoimmunity Research

Description

AOAH^-/- KO mice have a neo cassette replacing exon 1 of the acyloxyacyl hydrolase (Aoah) gene, making these mice useful when studying the regulation of immune responses to commensal bacteria.

Detailed description

AOAH^-/- KO mice have a neo cassette replacing exon 1, containing the translation start codon, of the acyloxyacyl hydrolase (Aoah) gene, abolishing gene function. AOAH is an enzyme found in dendritic cells (DCs), neutrophils, NK cells, monocytes, macrophages and renal proximal tubule cells that can remove secondary fatty acyl chains from the lipid A regions of diverse lipopolysaccharides (LPS). Deacylation of LPS is a mechanism by which vertrbrates may modulate host responses to the bacterial agonist. Mice homozygous for this allele are viable and fertile, and mice are normal until challenged parenterally with LPS. Subsequent to LPS exposure, they develop high polyclonal antibody titers, massive hepatomegaly, and prolonged endotoxin tolerance. After a single low dose intraperitoneal exposure to hexaacyl LPS, induced tolerance lasts for several weeks longer than that seen in wildtype animals. These mice are unable to regain normal immune responsiveness for many weeks/months after they are exposed in vivo to a small amount of LPS or Gram-negative bacteria. Although AOAH also has activity in vitro as a (phospho)lipase A1, in vivo substrates other than LPS have not been identified so far.

Development

A targeting vector was designed by Dr. Richard Kitchens (University of Texas Southwestern Medical School) to replace exon 1 including the translation start codon of the acyloxyacyl hydrolase (Aoah) gene with a neomycin resistance (neo) cassette. The construct was electroporated into 129S6/SvEvTac-derived embryonic stem (ES) cells. Correctly targeted ES cells were injected into blastocysts and the resulting chimeric mice were bred to 129S6/SvEvTac mice. The donating investigator reported that the AOAH^-/- mice were backcrossed 10 generations to C57BL/6J mice (see SNP note below). Upon arrival, sperm was cryopreserved. To establish our live colony, an aliquot of frozen sperm was used to fertilize C57BL/6J oocytes (Stock No. 000664).

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, all 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 C57BL/6N genetic background.

Allele

Symbol: Aoah^tm1Rsm
Name: targeted mutation 1, Robert S Munford
MGI accession ID: MGI:3044108
Generation method: Targeted
Attributes: Null/Knockout
Marker symbol: Aoah
Marker name: acyloxyacyl hydrolase
Chromosome: 13
Strain of origin: 129S6/SvEvTac
Molecular note: A 705 bp region encoding exon 1 including the translation start site was replaced with a neo cassette via homologous recombination.