NOD.B6N(Cg)-Foxn1^tm3(cre)Nrm/J

Stock number: 034796
Product name: NOD.Foxn1-Cre
Research areas: Dermatology Research, Internal/Organ Research, Research Tools

Description

Foxn1^ex9cre mice express Cre recombinase from the endogenous Foxn1 (forkhead box N1) locus without disruption of the Foxn1 coding sequence. When crossed with a strain containing loxP site-flanked sequence, Cre-mediated recombination results in deletion of the flanked region in thymic epithelial cells and keratinocytes.

Detailed description

Foxn1 is expressed in thymic epithelial cells throughout development in embryos aged E11.5 to adult mice. The spontaneous null mutation, Foxn1^nu, causes functional athymia due to failure of thymic anlage development past the initial progenitor stage. In this strain, the endogenous Foxn1 promoter drives expression of Cre recombinase. When crossed with a strain containing loxP site-flanked sequence, Cre-mediated recombination results in tissue-specific deletion of the flanked region. Recombination occurs in thymic epithelial cells and in keratinocytes in skin. Cre activity mimics the endogenous Foxn1 expression pattern. Mice that are homozygous for the targeted mutation are viable and fertile.

In an attempt to offer alleles on well-characterized or multiple genetic backgrounds, alleles are frequently moved to a genetic background different from that on which an allele was first characterized. It should be noted that the phenotype of these mice could vary from that originally described on a C57BL/6 background (Stock No. 018448). We may modify this strain description if necessary, as published results become available.

Development

A targeting vector containing IRES, cre coding sequence, and a FRT site flanked PGK-NEO cassette, was used to insert the cre coding sequence in-frame into the 3'UTR of exon 9 of the Foxn1 gene. The construct was electroporated into C57BL/6 derived LK-1 embryonic stem (ES) cells. Correctly targeted ES cells were injected into blastocysts. The resulting chimeric animals were initially crossed to BALB/c mice. The mice were then crossed with germline FLP recombinase expression, B6.Cg-Tg(ACTFLPe)9205Dym/J (Stock No. 005703), to remove the NEO selection cassette. The mice were then backcrossed to C57BL/6J mice for 4 generations. Upon arrival at The Jackson Laboratory, the mice were crossed to C57BL/6J (Stock No. 000664) at least once to establish Stock No. 018448.

Stock No. 018448 was subsequently backcrossed to NOD/ShiLtJ (Stock No. 001976) for 10 generations by the donating laboratory.

Allele

Symbol: Foxn1^tm3(cre)Nrm
Name: targeted mutation 3, Nancy R Manley
MGI accession ID: MGI:3760775
Generation method: Targeted
Attributes: Recombinase-expressing
Synonyms: Foxn1^ex9cre
Marker symbol: Foxn1
Marker name: forkhead box N1
Marker synonyms: D11Bhm185e; FKHL20; Hfh11; Rnu; RONU; TIDAND; TIDTA; TLIND; whn
Chromosome: 11
Strain of origin: C57BL/6NHsd
Expressed genes: cre,cre recombinase,bacteriophage P1
Site of expression: Cre activity mimics the endogenous Foxn1 expression pattern in thymic epithelial cells throughout development in embryos aged E11.5 to adult mice. When crossed with a strain containing loxP site-flanked sequence, Cre-mediated recombination occurs in thymic epithelial cells and in keratinocytes in skin.
Molecular note: An IRES-cre and floxed or frt neo cassette were inserted into the 3' end of exon 9. Insertion was confirmed by PCR of genomic DNA. Removal of the neo cassette by frt-mediated recombination following a cross with Tg(ACTFLPe)9205Dym mice results in a loss of ectopic cre expression but specific expression is retained. RT-PCR was used to confirm that endogenous gene expression was unaffected.