B6.129T(SJL)-Foxg1^{tm1.1(cre)Ddmo}/J

Stock number: 029690
Product name: Foxg1-IRES-Cre knock-in
Research areas: Developmental Biology Research, Neurobiology Research, Research Tools

Description

Foxg1-IRES-Cre knock-in mice contain a Cre recombinase sequence downstream of the Foxg1 promoter. These mice express FOXG1 in the telencephalon.

In contrast to the Foxg1-Cre knock-in/knock-out strains (Stock Nos. 006084 and 004337), this Foxg1-IRES-Cre strain coexpresses FOXG1 and Cre recombinase, preventing Foxg1-haploinsufficiency and ectopic cre expression.

Detailed description

Foxg1-IRES-Cre mice have an IRES-Cre cassette inserted 27 base pairs downstream of the stop codon of the forkhead box G1 (Foxg1) gene. The presence of the IRES-Cre cassette downstream of the stop codon allows for expression of FOXG1 and cre. FOXG1 is involved in the development of the emerging telencephalic region of the brain. Early expression of cre is evident in the telencephalon starting at E8.5-E9.0. Some expression is also observed in other head regions such as the otic vesicle, olfactory placode, anterior half of the optic vesicle, pharyngeal endoderm, and also fore gut by E10.5. Homozygous mice are viable and fertile. When these mice are bred with mice containing loxP-flanked sequence, Cre-mediated recombination will result in deletion of the floxed sequences in the Cre-expressing cells of the offspring.

The donating investigator notes that the Foxg1-IRES-Cre allele should be inherited maternally to ensure the highest and most consistent pattern and levels of Cre activity.

In contrast to the Foxg1-Cre knock-in/knock-out strains (Stock Nos. 006084 and 004337), this Foxg1-IRES-Cre strain coexpresses FOXG1 and Cre recombinase, preventing Foxg1-haploinsufficiency and ectopic cre expression.

If the recombinase activity pattern of this allele is further characterized by the Genetic Resource Science group at The Jackson Laboratory, such findings will be reported on the Mouse Genome Informatics (MGI) Allele Detail entry. This same information may also be found searching the MGI Recombinase Activity and MGI Gene Expression + Recombinase Activity Comparison Matrix.

Development

A targeting construct was designed to insert an internal ribosomal entry site (IRES) fused to Cre Recombinase, followed by a frt-flanked neomycin resistance (neo) cassette, 27 base pairs downstream of the stop codon of the forkhead box G1 (Foxg1) gene. This construct was electroporated into 129Sv/ter-derived embryonic stem (ES) cells. Correctly targeted ES cells were injected into C57BL/6 blastocysts and the resulting chimeric males were bred to C57BL/6 females. Offspring were bred to Tg(ACTFLPe)9205Dym expressing mice on a mixed genetic background to remove the neo cassette. Resulting Foxg1-IRES-Cre mice were crossed to remove the flp-expessing transgene and were subsequently bred to C57BL/6 mice for at least 8 generations by the donating lab (see SNP note below). Cryopreserved embryos were received, and were recovered to establish a live colony.

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. One the 43 markers on chromosome 19 is segregating, and 4 of 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 mixed C57BL/6J ; C57BL/6N genetic background.

 

Allele

Symbol: Foxg1^{tm1.1(cre)Ddmo}
Name: targeted mutation 1.1, Dennis D M O'Leary
MGI accession ID: MGI:5818697
Generation method: Targeted
Attributes: Recombinase-expressing
Synonyms: Foxg1-IRES-Cre
Marker symbol: Foxg1
Marker name: forkhead box G1
Marker synonyms: 2900064B05Rik; BF1; BF-1; BF1A; BF2; FHKL3; FKH2; FKHL1; FKHL2; FKHL3; FKHL4; FOXG1A; FOXG1B; FOXG1C; HBF-1; HBF2; HBF-2; HBF-3; HBF-G2; Hfh9; Hfhbf1; HFK1; HFK2; HFK3; KHL2; QIN; RATBF1A
Chromosome: 12
Strain of origin: 129T/Sv
Expressed genes: cre,cre recombinase,bacteriophage P1; Foxg1,forkhead box G1,mouse, laboratory
Site of expression: cre is expressed in the telencephalon starting at E8.5-E9.0, and in other head regions such as the otic vesicle, olfactory placode, anterior half of the optic vesicle, pharyngeal endoderm, and fore gut by E10.5.
Molecular note: An IRES-cre gene followed by an frt-flanked PGK-neo was inserted at 27bp downstream of the stop codon of the gene by homologous recombination in ES cells. Resulting mice were crossed with FLPe expressing mice to remove the PGK-neo cassette.