The Wwoxflox floxed allele has loxP sites flanking exon 1 of the WW domain-containing oxidoreductase gene (Wwox). Cre recombinase removes the floxed sequence and creates a null allele. These mice may be useful in studying central nervous system development, epilepsy, seizures, mental retardation, metabolic disorders, apoptosis and cancer.
C. Marcelo Aldaz, The University of Texas M.D. Anderson Cancer Center
The Wwoxflox allele has loxP sites flanking exon 1 of the Wwox gene. The Wwox gene encodes a member of the short-chain dehydrogenases/reductases (SDR) protein family that is proposed to function in metabolism, apoptosis and central nervous system development. Mice homozygous for the floxed allele are viable and fertile with no reported abnormalities. When bred to mice that express Cre recombinase, the resulting offspring may be useful in generating a tissue-specific Wwox knockout.
For example, when bred to germline Cre-expressing mice (EIIA-Cre; Stock No. 003724), the resulting Wwox global knockout homozygotes (WwoxΔCre/ΔCre) all die by 3 weeks of age with severe metabolic defects, impaired steroidogenesis, gonadal abnormalities, growth retardation, hypoglycemia, impaired hematopoeisis, bone formation/mineralization defects and epileptic seizures (spontaneous and audiogenic).
Breeding Wwoxflox mice with animals expressing Cre recombinase under control of the bovine keratin 5 promoter (BK5-Cre) or the MMTV promoter (MMTV-Cre; Stock No. 003553) generates two individual models of Wwox ablation in the mammary gland and other epithelial tissues. Both models show impaired mammary branching but no increased malignancies. The BK5-Cre;Wwox KO mice die prematurely (68-117 days of age) independent of gender for yet undetermined reasons. The MMTV-Cre;Wwox KO mice exhibit no impairments in survival or natural aging.
In addition, breeding Wwoxflox mice with animals expressing Cre recombinase under control of the albumin promoter (Alb-Cre; Stock No. 003574) generates mice with Wwox deletion in liver. The Alb-Cre;Wwox KO mice have altered lipid metabolism, but normal lifespan with no other reported abnormalities. Similarly, when Wwoxflox mice are bred to animals with the osterix promoter driving Cre recombinase expression in bone osteoblasts (Osx-Cre; e.g. Stock No. 006361), the resulting Osx-Cre;Wwox KO mice have normal lifespan with no other reported abnormalities.
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 it was first characterized. It should be noted that the phenotype of these C57BL/6-congenic Wwoxflox mice could vary from that originally described on a mixed C57BL/6;129SV genetic background. We may modify the strain description if necessary as published results become available.
A targeting vector was designed by Dr. C. Marcelo Aldaz (The University of Texas M.D. Anderson Cancer Center) to have a loxP site followed by a frt-flanked Pgk-neo cassette upstream of exon 1, and a second loxP site in intron 1 of the WW domain-containing oxidoreductase gene (Wwox) on chromosome 8. The construct was electroporated into 129S6-derived embryonic stem (ES) cells. Correctly targeted ES cells were injected into recipient blastocysts, and chimeric males were bred with C57BL/6J females for germline transmission. The resulting Wwoxflox mice were bred with C57BL/6J wildtype mice for several generations using a speed congenic approach. Males from the C57BL/6J-congenic colony (~99% C57BL/6) were sent to The Jackson Laboratory Repository in 2015. 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).
Of note, the donating investigator reports that, at least once during backcrossing, a heterozygous female was bred to a C57BL/6J inbred male (thus the Y chromosome of the congenic strain is of C57BL/6J origin).
|Allele Name||targeted mutation 1, Marcelo Aldaz|
|Allele Type||Targeted (Conditional ready (e.g. floxed), No functional change)|
|Gene Symbol and Name||Wwox, WW domain-containing oxidoreductase|
|Strain of Origin||129S6/SvEvTac|
|Molecular Note||An frt flanked neo cassette with a 5' loxP site was inserted upstream of exon 1 and an additional loxP site was inserted downstream of the exon.|
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 Wwoxflox mouse strain in a publication, please cite the originating article(s) and include JAX stock #028057 in your Materials and Methods section.