B6.Cg-Saa3^em1Litt Del(7Saa1-Saa2)1Itl/J

Stock number: 035697
Product name: SAA^TKO
Research areas: Immunology, Inflammation and Autoimmunity Research

Description

SAA^TKO mice carry a triple knock-out of mouse genes Saa1, Saa2, and Saa3, all of which are on Chromosome 7. This strain has been useful in studies of pathogenic Th17 cell involvement in inflammatory disease.

Detailed description

Serum amyloid A proteins (SAAs) dictate the balance between homeostatic and inflammatory Th17 cells. SAA^TKO mice carry a triple knock-out of mouse genes Saa1 (serum amyloid A 1), Saa2 (serum amyloid A 2), and Saa3 (serum amyloid A 3), all of which are on Chromosome 7. Exons 1 and 2 of both the Saa1 and Saa2 genes, in a head to head orientation, were replaced with a loxP/FRT-flanked neo cassette via homologous recombination. Exon 2 of the Saa3 gene was modified through CRISPR/Cas9 technology to incorporate two premature stop codons and a frame shift mutation.

Development

C57BL/6N-129S6 background mice carrying the Del(7Saa1-Saa2)1Itl mutation were backcrossed to C57BL/6J. Embryos were targeted by the Littman lab at New York University (PMID: 31866067) to introduce premature stop codons (TAG TAA), a frame shift mutation (A), and a HindIII site (AAGCTT) to exon 2 of the mouse Saa3 gene by CRISPR/Cas9 homology directed repair methodology. Nucleotide sequence CTGGGA became TAGTAAAAAGCTT. Translation of the Saa3 gene is terminated prematurely.

The Del(7Saa1-Saa2)1Itl mutation was originally made by the de Beer lab at the University of Kentucky (PMID: 20667817). The Saa1 and Saa2 genes are situated approximately 9 kb apart, in a head to head orientation, on mouse Chromosome 7. A 10.1 kb genome segment spanning exons 1 and 2 of both Saa1 and Saa2 was replaced with a loxP/FRT-flanked neo cassette via homologous recombination in (C57BL/6NTac x 129S6/SvEvTac)F1 embryonic stem (ES) cells. This mutation created a knock-out of both genes.

Compound mutant mice were backcrossed to C57BL/6J more than 6 generations to help remove off-target mutations by the donating laboratory. Upon arrival at The Jackson Laboratory, sperm was cryopreserved. Cryorecovery/live colony development will involve C57BL/6J (Stock No. 000664).

Allele

Symbol: Saa3^em1Litt
Name: endonuclease-mediated mutation 1, Dan R Littman
MGI accession ID: MGI:6467234
Generation method: Endonuclease-mediated
Attributes: Null/Knockout
Synonyms: 3KO
Marker symbol: Saa3
Marker name: serum amyloid A 3
Marker synonyms: l7R3; PIG4; SAA; SAA3; Saa-3; TP53I4
Chromosome: 7
Strain of origin: C57BL/6J
Molecular note: CRISPR/Cas9 genome editing is used to introduce premature stop codons (TAG TAA), a frame shift mutation (A), and a HindIII site (AAGCTT) in to exon 2.

Allele

Symbol: Del(7Saa1-Saa2)1Itl
Name: deletion, Chr 7, inGenious Targeting Laboratory
MGI accession ID: MGI:7496047
Generation method: Targeted
Attributes: Null/Knockout
Synonyms: SAA1.1/SAA2.1^-; Saa1/Saa2^tm1Itl
Marker symbol: Del(7Saa1-Saa2)1Itl
Marker name: deletion, Chr 7, inGenious Targeting Laboratory
Chromosome: 7
Strain of origin: (C57BL/6NTac x 129S6/SvEvTac)F1
Molecular note: 10.1 kb of genomic sequence, including exons 1 and 2 of Saa1 and Saa2 and the intervening sequence, was replaced with a loxP/FRT-flanked neomycin selection cassette. The absence of protein expression of both genes was confirmed by western blot analysis.