C.129(Cg)-Siglecf^tm1.2Avrk/J

Stock number: 025869
Product name: Siglec-F KO , SiglecF KO , Siglec5 KO
Research areas: Immunology, Inflammation and Autoimmunity Research

Description

Siglec-F KO mice display increased lung eosinophil infiltration and enhanced bone marrow and blood eosinophilia. They may be useful for studying eosinophil-mediated diseases and allergic inflammatory responses.

Detailed description

Siglec-F KO mice lack exons 1-3 of the sialic acid binding Ig-like lectin f (Siglecf) gene, abolishing gene expression. Siglec-F is a transmembrane protein that mediates sialic-acid dependent binding. Specifically, Siglec-F is expressed on mature circulating eosinophils and myeloid precursors in bone marrow, which figure prominently in allergic processes. Eosinophils are involved in the regulation of allergic inflammatory responses. These mice show increased lung eosinophil infiltration, enhanced bone marrow and blood eosinophilia, delayed resolution of lung eosinophilia, and reduced peribronchial cell apoptosis after ovalbumin challenge.Homozygous Siglec-F KO mice are viable and fertile.

In an attempt to offer alleles on well-characterized or multiple genetic backgrounds, alleles are frequently moved to a genetic background different from that on which an allele was first characterized. It should be noted that the phenotype could vary from that originally described. We will modify the strain description if necessary as published results become available.

Development

A targeting vector was designed to insert a loxP site upstream of exon 1 and a loxP-flanked neomycin resistance (neo) cassette downstream of exon 3 of the sialic acid binding Ig-like lectin f (Siglecf) gene. An arginine to alanine point mutation was introduced at amino acid 114 in exon 2 between the loxP sites. The construct was electroporated into (129X1/SvJ x 129S1/Sv)F1-Kitl⁺-derived R1 embryonic stem (ES) cells. Correctly targeted ES cells were transiently transfected with a cre expression plasmid to delete the neo cassette. Resulting ES cells contained multiple gene rearrangments; intact floxed-exons, intact floxed-neo cassette, or excision of the exons and the neo cassette. Correctly targeted ES cells, containing only the floxed-exons, were injected into C57BL/6 blastocysts and resulting chimeric mice were bred with B6.FVB-Tg(Zp3-cre)3Mrt/J transgenic mice to remove the floxed exons. Resulting Siglec-F^-/- were bred to remove the cre expressing transgene and progeny were subsequently bred to C57BL/6NHsd mice for at least 13 generations before being bred to BALB/cAnNHsd mice for at least 10 generations. Upon arrival, mice were bred to BALB/cByJ inbred mice (Stock No. 001026) for at least one generation to establish the colony.

Allele

Symbol: Siglecf^tm1.2Avrk
Name: targeted mutation 1.2, Ajit Varki
MGI accession ID: MGI:5543479
Generation method: Targeted
Attributes: Null/Knockout
Marker symbol: Siglecf
Marker name: sialic acid binding Ig-like lectin F
Marker synonyms: CD170; CD33L2; mSiglec-F; OBBP2; OB-BP2; Siglec5; SIGLEC-5
Chromosome: 7
Strain of origin: (129X1/SvJ x 129S1/Sv)F1-Kitl⁺
Molecular note: Cre-mediated recombination removed the floxed exons 1 through 3. This allele lacks the neomycin resistance cassette. Flow cytometry confirmed the absence of protein expression on peripheral blood leukocytes.