B6;129P2-Ctcf^tm2.2Gal/J

Stock number: 038621
Product name: Ctcf-flox
Research areas: Cancer Research, Cell Biology Research, Neurobiology Research, Research Tools

Description

Ctcf^f mice possess loxP sites flanking exons 3-12 and a lacZ reporter inserted into the Ctcf (CCCTC-binding factor) gene. These floxed mice are useful for tissue specific deletion of Ctcf in multiple applications including T cell development, cancer, neurobiology, and cardiology.

Detailed description

The Ctcf (CCCTC-binding factor) gene encodes the 11-zinc finger protein, sequence-specific DNA-binding protein, which is involved in chromatin organization, imprinting, and transcriptional regulation. Ctcf^f mice possess loxP sites flanking exons 3-12 and a lacZ reporter. Exon 3 contains the start codon and exon 12 contains the stop codon. Deletion of exons 3-12 results in a null allele. Mice that are heterozygous for this allele are viable and fertile, homozygotes are viable. The donating investigator did not use homozygotes for breeding. When bred to mice that express tissue-specific Cre recombinase, resulting offspring will have exons 3-12 deleted in the cre-expressing tissues resulting in a tissue specific null allele. Alternative splicing following cre-mediated removal of the exons 3-12 results in a lacZ fused to Ctcf exons 1 or 2. Germline deletion of Ctcf is embryonic lethal (early). Tissue-specific deletion of Ctcf is deleterious for virtually all tissues.

Development

The Ctcf^f targeting vector was designed to insert a loxP-flanked PMC1-neomycin cassette upstream of exon 3 and a loxP-flanked PGK-puromycin cassette followed by splice acceptor sequence and a lacZ reporter downstream of exon 12 of the CCCTC-binding factor (Ctcf) locus on chromosome 8. The construct was electroporated into 129P2/OlaHsd derived E14 embryonic stem (ES) cells. Correctly targeted ES cells were injected into blastocysts. The resulting male chimeras were crossed to C57BL/6 females. ES cells were isolated de novo from these Ctcf conditional mice, and infected with lentivirus expressing cre recombinase. ES cells without the neomycin or PGK-puromycin cassettes, but carrying loxP-flanked exons 3-12 and the lacZ reporter downstream, were selected and injected into blastocysts. The resulting male chimeras were crossed to C57BL/6 females. The strain has been crossed to C57BL/6 for at least 5 generations by the donating laboratory (see SNP note below). Upon arrival, mice were bred to C57BL/6J for at least 1 generation to establish the colony.

In 2023, a 48 SNP (single nucleotide polymorphism) panel analysis, with 43 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 males sent to The Jackson Laboratory Repository. Many of the 43 markers throughout the genome were segregating with 129, suggesting an incomplete backcross.

Allele

Symbol: Ctcf^tm2.2Gal
Name: targeted mutation 2.2, Niels Galjart
MGI accession ID: MGI:7509779
Generation method: Targeted
Attributes: Conditional ready (e.g. floxed); Reporter
Synonyms: Ctcf^f
Marker symbol: Ctcf
Marker name: CCCTC-binding factor
Marker synonyms: CFAP108; FAP108; MRD21
Chromosome: 8
Strain of origin: 129P2/OlaHsd
Molecular note: The targeting vector was designed to insert a loxP-flanked PMC1-neomycin cassette upstream of exon 3 and a loxP-flanked PGK-puromycin cassette followed by a splice acceptor sequence and a lacZ reporter downstream of exon 12. ES cells were isolated de novo from these Ctcf conditional mice, and infected with lentivirus expressing cre recombinase to remove floxed-neo and floxed-puro. ES cells with a single loxP upstream of an exon 3 and another single loxP after the exon 12 essentially flanking the exons 3-12 with lacZ reporter downstream, were selected.