B6.129P2-Csk^tm1Tara/J

Stock number: 018320
Research areas: Research Tools

Description

Exons 9 and 10 of these Csk mutant mice are flanked by loxP sites. When crossed with a cre recombinase-expressing strain, these mice are useful for creating tissue-specific knockouts of the gene. They may have applications in studies related to antigen receptor-mediated development and the regulation of T-lineage cell selection.

Detailed description

Csk (c-src tyrosine kinase) is a negative regulator of Src family protein tyrosine kinases (PTKs). It controls antigen receptor-mediated development and selection of T-lineage cells. Inactivation of the gene in immature thymocytes abrogates the requirement of preTCR, αβTCR and major histocompatibility complex (MHC) class II for the development of CD4⁺CD8⁺ double-positive and CD4⁺ single-positive thymocytes as well as peripheral CD4 αβT-lineage cells. TCR-MHC interactions have no impact on positive selection and commitment to the CD4 lineage in the absence of CSK. However, TCR-mediated negative selection of Csk-deficient, TCR transgenic cells is normal.

Exons 9 and 10 of these Csk mutant mice are flanked by loxP sites. Mice that are homozygous for this conditional allele are viable and fertile.

When crossed with a cre recombinase-expressing strain, these mice are useful for creating tissue-specific knockouts of the gene. Widespread deletion of expression is embryonic lethal.

For example, when bred to mice carrying Tg(Mx1-cre)1Cgn (see Stock No. 003556), interferon-induced Cre-mediated recombination results in disruption of alpha beta T cell development.

Development

A single loxP site was introduced to intron 8 and a herpes simplex virus thymidine kinase (HSV-TK)-Neomycin cassette flanked by loxP sites was inserted into intron 10. The mutation was created in 129P2/OlaHsd-derived E14.1 embryonic stem (ES) cells. The HSVtk-neo cassette was removed by transient transfection of a cre expression vector, leaving exons 9 and 10 flanked by loxP sites. The donating investigator reports that mutant mice were backcrossed to C57BL/6 for more than nine generations (see SNP note below) prior to sending to The Jackson Laboratory. Upon arrival, homozygous sperm was frozen. To generate the live colony, an aliquot of the frozen sperm was used to fertilize oocytes from C57BL/6J inbred females (Stock No. 000664).

A 32 SNP (single nucleotide polymorphism) panel analysis, with 27 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. While the 27 markers throughout the genome suggested a C57BL/6 genetic background, all 5 markers that determine C57BL/6J from C57BL/6N were found to be segregating. These data suggest the mice sent to The Jackson Laboratory Repository were on a C57BL/6N genetic background.

Allele

Symbol: Csk^tm1Tara
Name: targeted mutation 1, Alexander Tarakovsky
MGI accession ID: MGI:3050293
Generation method: Targeted
Attributes: Conditional ready (e.g. floxed); No functional change
Marker symbol: Csk
Marker name: c-src tyrosine kinase
Chromosome: 9
Strain of origin: 129P2/OlaHsd
Molecular note: A loxP site was inserted in intron 8 and a floxed HSVtk-neo selection cassette was inserted in intron 10. The selection cassette was subsequently removed from properly targeted ES cells by transient cre expression leaving exons 9 and 10 flanked by loxP sites.