Cyp27a1 floxed mice have loxP sites flanking exon 2 of the cytochrome P450, family 27, subfamily a, polypeptide 1 (Cyp27a1) gene. Exposure to Cre recombinase removes the floxed sequence - creating a null allele. These Cyp27a1f/f mice may be useful in studying oncology, vitamin D metabolism, and lipid homeostasis.
Dr. Donald P. McDonnell, Duke University
Cyp27a1 (cytochrome P450, family 27, subfamily a, polypeptide 1) is a ubiquitous enzyme which catalyzes cholesterol and other lipids. In humans, mutations in the CYP27A1 gene can lead to the autosomal recessive disease cerebrotendinous xanthomatosis. The Cyp27a1 floxed allele has loxP sites flanking exon 2 of the endogenous mouse Cyp27a1 gene.
Prior to introduction of Cre recombinase, mice heterozygous or homozygous for the Cyp27a1 floxed allele are viable and fertile with normal breeding, and have no gross physical or behavioral abnormalities. When Cyp27a1f/f are bred to mice that express Cre recombinase, the resulting offspring will have exon 2 deleted - creating a null allele in the cells/tissues as determined by the Cre promoter.
For example, when bred to myeloid specific Cre-expressing mice (LysMcre; see Stock No. 004781), the resulting myeloid cell knock-out homozygotes were confirmed to have no Cyp27a1 expression in bone marrow-derived macrophages (by PCR and western blotting). Additionally, the donating investigator reports having crossed these Cyp27a1 mice to Alb-cre (Stock No. 003574) for liver-specific deletion and Zp3-cre mice (Stock No. 003651) for germline deletion without detrimental impacts on viability or fertility.
The Cyp27a1 floxed allele was created in the laboratory of Dr. Donald P. McDonnell at Duke University. A targeting vector was constructed to insert a loxP site upstream of exon 2 of the cytochrome P450, family 27, subfamily a, polypeptide 1 (Cyp27a1) gene, and a FRT-flanked neomycin selection cassette and another loxP site downstream of exon 2. The construct was electroporated into (129S6/SvEvTac x C57BL/6NCr)F1 -derived G4 ES cells and then microinjected into recipient blastocysts. The resulting animals were then bred to FLPe-expressing mice (Stock No. 003946) to remove the FRT-flanked neo cassette and the line was subsequently backcrossed 10 generations to C57BL/6J prior to being donated to The Jackson Laboratory in 2020 (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).
In 2020, 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 rederived living colony at The Jackson Laboratory Repository. One of the 43 markers, on Chromosome 12, was segregating with 129. Also, two of the 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 mixed C57BL/6N;C57BL/6J genetic background.
|Allele Name||targeted mutation 1.1, Donald McDonnell|
|Allele Type||Targeted (Conditional ready (e.g. floxed))|
|Gene Symbol and Name||Cyp27a1, cytochrome P450, family 27, subfamily a, polypeptide 1|
|Strain of Origin||(129S6/SvEvTac x C57BL/6NCrl)F1|
|Molecular Note||The targeting vector was constructed to insert a loxP site upstream of exon 2 and a FRT-flanked neomycin selection cassette and another loxP site downstream of exon 2. Flp-mediated recombination removed the FRT-flanked neo cassette leaving exon 2 floxed.|
Both heterozygous and homozygous mice are viable and fertile with normal breeding, and no reported gross phenotypic or behavioral abnormalities.
When maintaining a live colony, heterozygous mice may be bred together, to wildtype mice from the colony or to C57BL/6J inbred mice (Stock No. 000664).
Alternatively, homozygous mice may be bred together.
When using the Cyp27a1f/f mouse strain in a publication, please cite the originating article(s) and include JAX stock #034712 in your Materials and Methods section.