B6.129S6(Cg)-Ntrk2^{tm3.1(cre/ERT2)Ddg}/J

Stock number: 027214
Strain synonyms: TrkB^CreER
Research areas: Developmental Biology Research, Neurobiology Research, Research Tools

Description

These TrkB^CreER mutant mice express Cre-ERT2 from the mouse Ntrk2 promoter. Endogenous NTRK2 expression is knocked out. Treatment with 4-hydroxytamoxifen (OHT) enables the Cre-mediated excision of introduced floxed sequences in dorsal root ganglion neurons.

Detailed description

These TrkB^CreER mutant mice express Cre-ERT2 (Cre recombinase fused to a mutant form of the human estrogen receptor ligand binding domain) from the mouse Ntrk2 promoter. Endogenous NTRK2 expression is knocked out. Treatment with synthetic estrogen receptor 4-hydroxytamoxifen (OHT) enables the Cre fusion protein to access the nuclear compartment for directed excision of floxed sequences bred into this strain.

No overt phenotype is observed in TrkB^CreER heterozygotes. Homozygotes are not viable. Expression of Cre is consistent with that of Ntrk2 expression.

When progeny from a cross with Rosa26^LSL-tdTomato mice (see Stock No. 007909) are treated with a single injection of OHT during embryonic development, excision of a floxed Stop enables constitutive tdTomato labeling of medium diameter, Ntrk2-expressing dorsal root ganglion neurons of adult mice.

Development

A Cre recombinase-estrogen receptor T2 (CreERT2) fusion-Frt-Neomycin-Frt-loxP cassette was introduced into the first coding ATG of exon 2 of the Ntrk2 (TrkB) gene. All 212 bp of exon 2 (encoding the first 70 amino acids containing entire signal peptide) were replaced. The mutation was created via homologous recombination in 129S6/SvEvTac-derived embryonic stem (ES) cells. TrkB^CreER heterozygous mice were generated through crosses with Actb-FlpE mice (C57BL/6 background) to remove the neomycin selection cassette. TrkB^CreER mice negative for neomycin were then backcrossed to C57BL/6J for at least 5 generations by the donating laboratory. Homozygotes die at birth.

Allele

Symbol: Ntrk2^{tm3.1(cre/ERT2)Ddg}
Name: targeted mutation 3.1, David D Ginty
MGI accession ID: MGI:5616440
Generation method: Targeted
Attributes: Recombinase-expressing; Inducible
Marker symbol: Ntrk2
Marker name: neurotrophic tyrosine kinase, receptor, type 2
Chromosome: 13
Strain of origin: 129S6/SvEvTac
Expressed genes: cre/ERT2,Cre recombinase and estrogen receptor 1 (human) fusion gene,
Site of expression: Cre-ERT2 fusion protein is expressed Ntrk2-expressing cells in dorsal root ganglion neurons.
Molecular note: A Cre recombinase-estrogen receptor T2 (CreERT2) fusion-FRT-Neomycin-FRT-loxP cassette was introduced into the first coding ATG of exon 2. All 212 bp of exon 2 (encoding the first 70 amino acids containing entire signal peptide) were replaced.