B6.Cg-Ccl2^tm1.1Pame/J

Stock number: 016849
Product name: Ccl2-RFP^flox
Research areas: Immunology, Inflammation and Autoimmunity Research, Research Tools

Description

These floxed mutant mice contain loxP sites flanking exons 2-3 of the Ccl2 gene which has been modified with a red fluorescent protein gene (mcherry). Fluorescence is seen in all Ccl2-expressing cells. When these mutant mice are bred to mice that express Cre recombinase, resulting offspring will have exons 2-3, as well as RFP, deleted in the cre-expressing tissue.

Detailed description

These Ccl2-RFP^lox/lox mice contain loxP sites flanking exons 2-3 of the chemokine (C-C motif) ligand 2 (Ccl2 or Mcp1) gene, as well as an HA peptide followed by an aphthovirus 2A cleavage site and a cleavable red fluorescent protein (mcherry) at the 3' end of exon 3. Homozygous mice are viable and fertile. MCP1 is a chemokine required for the movement of monocytes from bone marrow into the blood stream during their recruitment to sites of injury and infection. Fluorescence is seen in all MCP1 expressing cells. When these mutant mice are bred to mice that express Cre recombinase, resulting offspring will have exons 2-3, as well as RFP expression, deleted in the cre-expressing tissue. Deletion of MCP1 results in decreased monocyte emigration from the bone marrow upon LPS stimulation and increased susceptibility to infection. These mice may be useful for studying emigration of inflammatory monocytes from the bone marrow after infection.

When bred to mice carrying Tg(Tek-cre)12Flv (Stock No. 004128) and induced by LPS or bacterial infection, Cre recombinase expression in endothelial cells results in abnormal monocyte migration.

When bred to mice carrying Tg(Nes-cre)1Kln (Stock No. 003771) and induced by LPS or bacterial infection, Cre recombinase expression in the nervous system results in abnormal monocyte migration.

Development

A targeting vector was designed to insert a loxP site upstream of exon 2 and a second loxP site downstream of exon 3 of the chemokine (C-C motif) ligand 2 (Ccl2 or Mcp1) gene. The targeting vector also inserted an HA peptide followed by an aphthovirus 2A cleavage site, a cleavable red fluorescent protein (mcherry), and a frt-flanked neomycin (neo) resistance cassette at the 3' end of exon 3. The construct was electroporated into B6(Cg)-Tyr^c-2J/J derived embryonic stem (ES) cells. Correctly targeted ES cells were injected into blastocysts and resulting chimeric mice were bred to C57BL/6J mice. Offspring, heterozygous for this Ccl2 allele, were bred with B6.Cg-Tg(ACTFLPe)9205Dym/J transgenic mice (Stock No. 005703) to delete the neo cassette, and progeny were crossed to remove the Flp-expressing transgene, resulting in a colony homozygous for the Ccl2-RFP^lox/lox allele. These mice were backcrossed to C57BL/6J mice for at least 10 generations. Upon arrival, mice were bred to C57BL/6J inbred mice (Stock No. 000664) for at least one generation.

Allele

Symbol: Ccl2^tm1.1Pame
Name: targeted mutation 1.1 Eric G Pamer
MGI accession ID: MGI:4950271
Generation method: Targeted
Attributes: Conditional ready (e.g. floxed); No functional change
Marker symbol: Ccl2
Marker name: chemokine (C-C motif) ligand 2
Chromosome: 11
Strain of origin: B6(Cg)-Tyr^c-2J
Molecular note: A loxP site was inserted upstream of exon 2. Exon 3 was replaced with a modified exon 3 with an HA-2A cleavable mCherry and 3' loxP site. A floxed neo cassette used for selection purposes was removed by cre-mediated recombination.