Rhox10 floxed mice have loxP sites flanking exon 2 of the X chromosome-linked Rhox10 gene. Exposure to Cre recombinase removes the floxed sequence - creating a null allele. These Rhox10 floxed mice may be useful in studying spermatogenesis and fertility.
Dr. Miles Wilkinson, University of California San Diego
The Rhox10 gene encodes the homeobox transcription factor, RHOX10, which is expressed in the reproductive tract and is involved in the development and migration of spermatogonial stem cells.
The Rhox10 floxed allele has loxP sites flanking exon 2 of the Rhox10 gene. Prior to introduction of Cre recombinase, mice heterozygous or homozygous for the Rhox10 floxed allele are viable and fertile with normal breeding, and have no gross physical or behavioral abnormalities. However, the donating investigator reports that Rhox10 floxed mice have lower levels of Rhox10 mRNA expression than wild-type mice.
When Rhox10 floxed mice 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 germline Cre-expressing mice (E2A-Cre; see Stock No. 003724), the resulting Rhox10 global knock-out males exhibit reduced testis weight and lowered sperm count. The sperm exhibit abnormal morphology including perturbed head morphology and rolled back tails. Histological analysis also reveals a progressive decline in seminiferous tubule morphology consistent with a defect in spermatogonial stem cells, with tubule sections lacking germ cells when examined at 12 or 24 weeks (Song et al., 2016).
The Rhox10 floxed allele was created in the laboratory of Dr. Miles F. Wilkinson (University of California, San Diego). First, a targeting vector was designed to insert a loxP site followed by a frt-flanked PGK-neo cassette upstream of exon 2, and a second loxP site just downstream of exon 2 of the reproductive homeobox 10 locus (Rhox10) on the X chromosome. The construct was electroporated into 129-derived embryonic stem (ES) cells. Correctly targeted ES cells were injected into recipient blastocysts, and chimeric mice were bred with C57BL/6J for germline transmission. The resulting Rhox10 floxed colony was then backcrossed to C57BL/6J mice for at least 7 generations prior to sending frozen sperm to The Jackson Laboratory Repository in 2020 (see SNP note below). 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. Many of the 43 markers throughout the genome were segregating with 129, suggesting an incomplete backcross.
|Allele Name||targeted mutation 1, Miles F Wilkinson|
|Allele Type||Targeted (Conditional ready (e.g. floxed))|
|Gene Symbol and Name||Rhox10, reproductive homeobox 10|
|Strain of Origin||129|
|Molecular Note||The targeting vector is designed to insert a loxP site followed by an FRT-flanked PGK-neo cassette upstream of exon 2, and a second loxP site just downstream of exon 2.|
Both heterozygous/hemizygous 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 females and hemizygous male mice may be bred together.
When using the Rhox10flox mouse strain in a publication, please cite the originating article(s) and include JAX stock #035193 in your Materials and Methods section.