STOCK Ltf^{tm1(icre)Tdku}/J

Stock number: 026030
Research areas: Reproductive Biology Research, Research Tools

Description

Ltf-iCre knockin/knockout mice express a codon optimized Cre recombinase and EGFP under the direction of the Ltf gene. These mice are suitable for applications requiring Cre-mediated recombination in uterine epithelium.

Detailed description

In Ltf-iCre mice, portions of exon 1 and intron 1 of the Ltf (lactotransferrin) gene are replaced by a codon optimized Cre recombinase and EGFP. The presence of iCre and EGFP abolishes expression of Ltf. LTF is a non-heme iron-binding glycoprotein expressed in the uterine epithelium of adult mice. LTF is highly responsive to estrogen in the mouse uterus. 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 uterine epithelium in adult females, and in immature females after estrogen treatment. EGFP expression is observed in the uterine epithelium of mature mice. Cre activity is highest in the uterine epithelium with some activity also found in neutrophils, spleen, and esophagus.

Development

A targeting construct was designed to replace part of exon1 and intron 1 of the Ltf (lactotransferrin) gene with a codon optimized Cre recombinase gene (iCre) followed by an internal ribosome entry site (IRES), an enhanced green fluorescent protein (EGFP), a polyadenylation site, and a frt-flanked neomycin/kanamycin resistance (neo/kan) cassette. This construct was electroporated into (129S6/SvEvTac x C57BL/6NCr)F1-derived G4 embryonic stem (ES) cells. Correctly targeted ES cells were injected into B6(Cg)-Tyr^c-2J/J blastocysts and the resulting chimeric males were bred to B6(Cg)-Tyr^c-2J/J females for two generations. These Ltf-iCre mice were maintained on a mixed B6;129 background. Upon arrival at The Jackson Laboratory, mice were bred to C57BL/6J inbred mice (Stock No. 000664) for at least one generation to establish the colony, and the Tyr^c-2J allele was bred out of the colony.

Allele

Symbol: Ltf^{tm1(icre)Tdku}
Name: targeted mutation 1, Takiko Daikoku
MGI accession ID: MGI:5581966
Generation method: Targeted
Attributes: Recombinase-expressing
Synonyms: Ltf-iCre; Ltf^{tm1(icre,EGFP)Tdku}
Marker symbol: Ltf
Marker name: lactotransferrin
Chromosome: 9
Strain of origin: (129S6/SvEvTac x C57BL/6NCrl)F1
Expressed genes: cre,cre recombinase,bacteriophage P1; GFP,Green Fluorescent Protein,
Site of expression: EGFP expression is observed in the uterine epithelium of mature mice.
Molecular note: A targeting construct was designed to replace part of exon1 and intron 1 of the gene with a codon optimized Cre recombinase gene (iCre) followed by an internal ribosome entry site (IRES), an enhanced green fluorescent protein (EGFP), a polyadenylation site, and a frt-flanked neomycin/kanamycin resistance (neo/kan) cassette.