B6(Cg)-Ski^{tm1c(EUCOMM)Hmgu}/SfzJ

Stock number: 040495
Product name: SKI^fl
Research areas: Immunology, Inflammation and Autoimmunity Research, Internal/Organ Research, Research Tools

Description

SKI^fl/fl floxed mice have loxP sites flanking exons 1-2 of the Ski gene. These mice may be useful when studying the role of SKI in regulating medullary thymic epithelial cell (mTEC) differentiation and the control peripheral T cell responses.

Detailed description

SKI^fl/fl floxed mice have loxP sites flanking exons 1-2 of the ski sarcoma viral oncogene homolog (avian) (Ski) gene. Ski encodes a nuclear protooncogene that plays a role in both cancer progression and immune function due to its involvement in the differentiation of medullary thymic epithelial cells (mTECs). It has been implicated as a negative regulator of TGF-β leading to its involvement in the development of cancer due to the role that TGF-β plays in regulating cellular functions such as cell proliferation, apoptosis, specification, and developmental fate.

Homozygous SKI^fl/fl mice are viable and fertile. When bred to mice that express tissue-specific Cre recombinase, resulting offspring will have exons 1-2 deleted in the cre-expressing tissues.

When bred to a mouse line with thymic epithelial cell-specific cre-expression (similar to Stock No. 018448), deletion of SKI reduces the mTEC compartment in the thymus and tissue restricted antigen (TRA) expression in mTECs is altered. Naïve CD4 T cells purified from SKI-deleted mice show a defect in proliferation in vitro after global T cell receptor (TCR) stimulation and mice are significantly protected from developing experimental autoimmune encephalomyelitis (EAE).

Development

The L1L2_Bact_P cassette was inserted at position 155244938 of Chromosome 4 upstream of exon 1 of the ski sarcoma viral oncogene homolog (avian) (Ski) gene. The cassette is composed of a frt site followed by lacZ sequence and a loxP site. This first loxP site is followed by neomycin resistance (neo) cassette, a second frt site and a second loxP site. A third loxP site was inserted downstream of exon 2. The mutation was generated in C57BL/6N-A^tm1Brd-derived JM8A3.N1 embryonic stem (ES) cells. The donating investigator acquired correctly targeted ES cells and injected them into blastocysts, and the chimeric mice were bred to Flp deleter mice to remove the lacZ and neo cassettes. Resulting SKI^fl floxed offspring were bred to C57BL/6J mice for at least 12 generations by the donating laboratory (see SNP note below). Cryopreserved sperm was sent to The Jackson Laboratory. To establish our live colony, an aliquot of frozen sperm was used to fertilize C57BL/6J oocytes (Stock No. 000664).

In 2025, 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. Four of the 5 markers that determine C57BL/6J from C57BL/6N were found to be segregating, including the rd8 recessive mutation associated with retinal degeneration on Chromosome 1 within the Crb1 locus. These data suggest the mice sent to The Jackson Laboratory Repository were on a mixed C57BL/6N;C57BL/6J genetic background.

Allele

Symbol: Ski^{tm1c(EUCOMM)Hmgu}
Name: targeted mutation 1c, Helmholtz Zentrum Muenchen GmbH
MGI accession ID: MGI:8161819
Generation method: Targeted
Attributes: Conditional ready (e.g. floxed)
Synonyms: Ski^fl; SKI-fl
Marker symbol: Ski
Marker name: ski sarcoma viral oncogene homolog (avian)
Marker synonyms: 2310012I02Rik; 2610001A11Rik; c-ski; MGC:8300; RGD1565591; SGS; SKV
Chromosome: 4
Strain of origin: C57BL/6N-A^tm1Brd
Molecular note: The L1L2_Bact_P cassette was inserted at position 155244938 of Chromosome 4 upstream of the critical exon(s) (Build GRCm39). The cassette is composed of an FRT site followed by lacZ sequence and a loxP site. This first loxP site is followed by a neomycin resistance gene under the control of the human beta-actin promoter, SV40 polyA, a second FRT site and a second loxP site. A third loxP site is inserted downstream of the targeted exon(s) at position 155245842. The critical exon(s) is/are thus flanked by loxP sites. A "conditional ready" (floxed) allele was created by flp recombinase expression in mice carrying this allele to remove the lacZ sequence and neo selection cassette, leaving loxP sites flanking the critical exon(s). Further information on targeting strategies used for this and other IKMC alleles can be found at http://www.informatics.jax.org/mgihome/nomen/IKMC_schematics.shtml