Rab25 knock-out mice carry a neo cassette and three tandem stop codons inserted into exon 2 of the RAB25, member RAS oncogene family locus. When combined with other known oncogenes, Rab25 deficient mice exhibit accelerated tumor growth. These mice may be useful in studying oncology and tumorigenesis.
Krishna Rao, SIU School of Medicine
The Rab25 gene encodes the RAB25, member RAS oncogene family protein, a small GTPase highly expressed in epithelial cells of the gastrointestinal tract, lungs, and kidneys, which is associated with membrane recycling and trafficking to the plasma membrane. Altered Rab25 expression has been associated with altered growth characteristics in breast and ovarian cancer cell lines.
The Rab25 knock-out allele has a PGK-neo cassette followed by three tandem in-frame stop codons inserted into exon 2 of the Rab25 gene. No Rab25 mRNA (by Southern blot) or protein expression from the knock-out allele is detected in homozygous intestinal mucosa (by western blot analysis). The donating investigator reports that homozygous Rab25 knock-out mice on the C57BL/6J background are viable and fertile and show no overt behavioral, anatomical, or pathological abnormalities for at least one year. Mice heterozygous for the Rab25 KO allele are viable and fertile with normal breeding, and have no gross physical or behavioral abnormalities, but express the Rab25 protein at approximately 50% of wildtype controls. When combined with the ApcMin mutation (Stock No. 002020), Rab25 knock-out mice exhibit a 4-fold increase in intestinal polyps and a 2-fold increase in the incidence of colonic tumors, compared to mice carrying the ApcMin mutation alone (Nam et al. 2010).
The Rab25 knock-out allele (also called RAB25-) was created in the laboratory of Dr. James Goldenring (Vanderbilt University). First, a targeting vector was designed to insert a PGK-neo cassette followed by three tandem in-frame stop codons into exon 2 of the RAB25, member RAS oncogene family (Rab25) locus on chromosome 3. The construct was electroporated into (129X1/SvJ x 129S1/Sv)F1-Kitl+-derived R1 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 RAB25- colony was then backcrossed to C57BL/6J mice for at least 8 generations prior to sending males to The Jackson Laboratory Repository 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 throughout the genome, on Chromosome 11, was segregating with 129. Also, 3 of the 5 markers that determine C57BL/6J from C57BL/6N, on Chromosomes 1, 15, and 19 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, James R Goldenring|
|Allele Type||Targeted (Null/Knockout)|
|Gene Symbol and Name||Rab25, RAB25, member RAS oncogene family|
|Strain of Origin||(129X1/SvJ x 129S1/Sv)F1-Kitl+|
|Molecular Note||The neomycin resistance gene along with 3 tandem in-frame stop codons was inserted into the second exon. Western blot and immunostaining indicated a lack of protein expression in the intestines of homozygous mice.|
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 Rab25- mouse strain in a publication, please cite the originating article(s) and include JAX stock #034226 in your Materials and Methods section.