B6.129P2-Aicda^{tm1.1(cre/ERT2)Crey}/J

Stock number: 033897
Product name: AID-Cre-ERT2
Research areas: Research Tools

Description

AID-Cre-ERT2 knock-in/knock-out mice have an inducible Cre/ERT2 fusion gene inserted into exon 2 of the activation-induced cytidine deaminase (Aicda or AID) gene. When combined with a floxed reporter, these mice can be used to monitor memory B cell populations.

Detailed description

AID-Cre-ERT2 mice express an inducible Cre/ERT2 sequence that is fused with first 4 amino acids of exon 2 of the activation-induced cytidine deaminase (Aicda or AID) gene. Aicda encodes a DNA-editing deaminase that is involved in the initiation of somatic hypermutation and class-switch recombination in immunoglobulin genes and is expressed mainly in germinal center B cells. Mice that are homozygous for this AID-Cre-ERT2 knock-in/knock-out allele are viable and fertile, but lack serum IgG and develop a mild immune deficiency, as they are AID-deficient and are unable to generate class-switched antibodies and mutations on immunoglobulin V genes. SPF (specific pathogen-free) conditions are recommended.

When crossed with a strain containing a loxP site flanked sequence of interest, offspring can be useful for generating tamoxifen-induced, Cre-mediated targeted deletions. For example, when combined with a floxed reporter such as B6.129X1-Gt(ROSA)26Sor^tm1(EYFP)Cos/J (Stock No. 006148) these mice can be used to monitor memory B cell populations.

Development

A targeting vector containing a Cre recombinase/ERT2 fusion that includes the sequence of the first four amino acids of Aicda (including the the 4 nucleotides downstream of the splice site in exon 2), followed by a loxP-flanked neomycin resistance cassette was designed to replace exon 2 of the Aicda gene. In addition, the splice-acceptor site was mutated to prevent splicing events from eliminating the Cre/ERT2 sequence. The construct was electroporated into 129P2/OlaHsd-derived E14.1 embryonic stem (ES) cells which were transiently transfected with a Cre recombinase vector to remove the selection cassette. Correctly targeted ES cells were injected into blastocysts. The resulting chimeric animals were crossed to C57BL/6 and offspring were backcrossed to C57BL/6 for 20 generations. Upon arrival, mice were bred to C57BL/6J for at least one generation to establish the live colony.

Allele

Symbol: Aicda^{tm1.1(cre/ERT2)Crey}
Name: targeted mutation 1.1, Claude-Agnes Reynaud
MGI accession ID: MGI:4437052
Generation method: Targeted
Attributes: Recombinase-expressing; Inducible; Null/Knockout
Synonyms: AID-Cre-ERT2
Marker symbol: Aicda
Marker name: activation-induced cytidine deaminase
Marker synonyms: aid; ARP2; CDA2; HEL-S-284; HIGM2
Chromosome: 6
Strain of origin: 129P2/OlaHsd
Site of expression: germinal center B cells
Molecular note: A targeting construct was designed to insert a cre/ERT2 sequence, an SV40 polyA site, and a floxed neo selection cassette into the Aicda locus, replacing exon 2 and fusing with sequence encoding the first 4 amino acids, including 4 bases downstream of the exon 2 splice site. The splice acceptor site of Aicda intron 2-3 was mutated to prevent splicing events that could eliminate the cre/ERT2 sequence. E14.1 ES cells were electroporated with the linearized vector. Recombinant clones were transiently transfected with a cre-expressing vector to excise the neo cassette.