B6.Cg-Cd19^{tm1.1(cre)Cgn} Rps15^tm1.1Cjwu/J

Stock number: 037632
Product name: Cd19-Cre/Rps15-S138F flox
Research areas: Cancer Research, Hematological Research, Immunology, Inflammation and Autoimmunity Research, Research Tools

Description

These Cd19-Cre/Rps15-S138F floxed mice contain a cre-conditional S138F mutation in the Rps15 gene, and also contain B cell-expressing cre recombinase allele. These mutant mice are useful when studying chronic lymphocytic leukemia (CLL) and translation dysregulation and defects in ribosome synthesis and assembly.

Detailed description

The targeted Rps15 gene encodes ribosomal protein S15, a cytoplasmic ribosomal protein that is a component of the 40S subunit and has been found to be activated in various tumors. This mutation is analogous to the human Rps15-S138F mutation associated with malignant transformation of B cells in chronic lymphocytic leukemia (CLL). CLL is the most common B cell leukemia in adults, involving the peripheral blood and lymphoid organs such as lymph nodes and bone marrow. Rps15-S138F floxed conditional knock-in mice carry an allele with a knock-in sequence of loxP sites flanking copies of exons 3-4 and a STOP codon. cDNA encoding exons 3 and 4, containing a serine to phenylalanine mutation (S138F), were inserted downstream of the second loxP site.

This strain also contains a Cd19cre knock-in/knock-out allele present in Stock No. 006785 mice, resulting in removal of STOP codon and subsequent expression of Rps15-S138F specifically in B cells. Heterozygous expression of the S138F mutation disrupts B cell function and induced CLL-like disease in mice at 20 months of age with ~37% penetrance due to upregulation of Myc targets, B cell receptor signaling, and Zap70 expression, all markers of aggressive CLL-like disease.

Double homozygous Cd19cre/Rps15-S138F floxed knock-in mice are viable and fertile.

Development

The Rps15-S138F targeting vector contains, from 5' to 3', a loxP site, cDNA encoding exons 3-4 of the ribosomal protein S15 (Rps15) gene, a STOP codon containing 3xSV40 polyA, a frt-flanked neomycin resistance (neo) cassette, and a second loxP site inserted downstream of endogenous exon 2, replacing endogenous exons 3-4. cDNA encoding exons 3-4, containing a serine to phenylalanine mutation (S138F), were inserted downstream of the second loxP site. The S138F mutation is analogous to the human Rps15-S138F mutation associated with malignant transformation of B cells in chronic lymphocytic leukemia (CLL). The construct was electroporated into C57BL/6-derived embryonic stem (ES) cells. Correctly targeted ES cells were injected into blastocysts and the resulting chimeric animals were bred to germline FLP deleter mice to remove the neo cassette. Resulting mice, lacking the neo cassette, were then bred to Cd19cre knock-in/knock-out mice (Stock No. 006785) for two generations to produce double homozygous mice before being backcrossed to C57BL/6J mice (Stock No. 000664) for 20 generations by the donating laboratory (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.

Genotyping at The Jackson Laboratory shows that the neo cassette originally present in the Cd19cre allele has also been removed.

In 2023, 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 males sent to The Jackson Laboratory Repository. One of the 5 markers that determine C57BL/6J from C57BL/6N were found to be segregating on Chromosome 19. These data suggest the mice sent to The Jackson Laboratory Repository were on a mixed C57BL/6N;C57BL/6J genetic background.

Allele

Symbol: Rps15^tm1.1Cjwu
Name: targeted mutation 1.1, Catherine Wu
MGI accession ID: MGI:7378408
Generation method: Targeted
Attributes: Conditional ready (e.g. floxed); Humanized sequence
Synonyms: Rps15-S138F
Marker symbol: Rps15
Marker name: ribosomal protein S15
Marker synonyms: insulinoma; rat insulinoma gene; RIG; S15; uS19
Chromosome: 10
Strain of origin: C57BL/6
Molecular note: The vector contains, from 5' to 3' a loxP site, cDNA encoding exons 3-4 of Rps15, a STOP codon containing 3xSV40 polyA, an FRT-flanked neomycin resistance (neo) cassette, and a second loxP site inserted downstream of endogenous exon 2, replacing endogenous exons 3-4. The cDNA encoding exons 3-4 contains a serine to phenylalanine mutation (S138F) is inserted downstream of the second loxP site. The S138F mutation is analogous to the human Rps15-S138F mutation associated with malignant transformation of B cells in chronic lymphocytic leukemia (CLL). Flp-mediated recombination removed the neo cassette.

Allele

Symbol: Cd19^{tm1.1(cre)Cgn}
Name: targeted mutation 1.1, University of Cologne
MGI accession ID: MGI:8245334
Generation method: Targeted
Attributes: Recombinase-expressing
Marker symbol: Cd19
Marker name: CD19 antigen
Marker synonyms: B4; CVID3
Chromosome: 7
Strain of origin: 129P2/OlaHsd
Molecular note: In-frame insertion of a cre recombinase gene into the first coding exon followed by an fFRT site flanked neomycin resistance gene cassette. A frameshift mutation was also introduced into exon 5. This allele expresses cre recombinase specifically in B lineage cells throughout development. The FLP recombinase removed the neo cassette.