B6.Cg-Tg(CDX2-cre*)189Erf/J

Stock number: 009352
Research areas: Internal/Organ Research, Research Tools

Description

These CDX2P9.5-G22Cre transgenic mice harbor a nuclear-localized Cre recombinase with 22 guanine nucleotide repeat between initiating methionine (ATG) codon and the remainder of the coding region altering the cre reading frame. Presumably, following a somatic mutation that results in some frameshift mutation(s) in the guanine nucleotide tract in a subset of somatic cells, resultant expression of a functional Cre recombinase is driven by a 9.5 kb human caudal type homeo box 2 (CDX2) promoter/enhancer sequence. These CDX2P9.5-G22Cre transgenic mice may be useful as a somatic mutation reporter strain and/or to generate conditional mutations in colorectal epithelial cells.

Detailed description

Mice hemizygous for the CDX2P9.5-G22Cre transgene are viable and fertile. The 9.5 kb human caudal type homeo box 2 (CDX2) promoter/enhancer sequence is prevented from driving nuclear-localized Cre recombinase expression as a 22 guanine nucleotide repeat tract between initiating methionine (ATG) codon and the remainder of the coding region alters the cre reading frame. Presumably, following a somatic mutation that results in some frameshift mutation(s) in the guanine nucleotide tract in a subset of somatic cells, resultant expression of a functional Cre recombinase is observed predominantly in colonic epithelium during late gestation and in adult tissues. Specifically, mosaic Cre recombinase expression would be observed in epithelium from the distal ileum and cecum, and mainly the proximal and distal colon from the crypt base to the luminal surface. Cre recombinase expression may also be observed in a few caudal-derived cells during early development. When these transgenic mice are bred with mice containing a loxP-flanked sequence of interest, Cre-mediated recombination is expected to result in deletion of the floxed sequences in these tissues of the offspring that reactivate cre expression. These CDX2P9.5-G22Cre transgenic mice may be useful as a somatic mutation reporter strain and/or to generate conditional mutations in colorectal epithelial cells.

Development

The CDX2P9.5-G22Cre transgene was designed with a 9.5 kb promoter fragment from the 5' flanking sequences of human caudal type homeo box 2 (CDX2) gene, a nuclear-localized Cre recombinase gene modified with a 22 guanine nucleotide repeat tract between its initiating methionine (ATG) codon and the remainder of the Cre-coding region, and a bovine growth hormone polyadenylation cassette. This transgene was injected into (C57BL/6J x SJL/J) hybrid cells. Transgenic founders (line 189) were found to have approximately 80 copies of the transgene and were bred to C57BL/6J mice. The donating investigator reports that this strain was maintained by breeding hemizygous mice with C57BL/6J inbred mice for 7 generations prior to arrival at The Jackson Laboratory. Upon arrival, CDX2P9.5-G22Cre transgenic mice were bred to C57BL/6J inbred mice (Stock No. 000664) for at least one generation to establish the colony. The Y chromosome may not have been fixed to the C57BL/6 genetic background.

Allele

Symbol: Tg(CDX2-cre*)189Erf
Name: transgene insertion 189, Eric R Fearon
MGI accession ID: MGI:3843611
Generation method: Transgenic
Attributes: Recombinase-expressing
Marker symbol: Tg(CDX2-cre*)189Erf
Marker name: transgene insertion 189, Eric R Fearon
Chromosome: UN
Strain of origin: (C57BL/6J x SJL/J)
Expressed genes: cre,cre recombinase,bacteriophage P1
Site of expression: mosaic Cre recombinase expression is observed in epithelium from the distal ileum and cecum, and mainly the proximal and distal colon from the crypt base to the luminal surface. Cre recombinase expression may also be observed in a few caudal-derived cells during early development.
Molecular note: The CDX2P9.5-G22Cre transgene was designed with a 9.5 kb promoter fragment from the 5' flanking sequences of human caudal type homeo box 2 (CDX2) gene, a nuclear-localized Cre recombinase gene modified with a 22 guanine nucleotide repeat tract between its initiating methionine (ATG) codon and the remainder of the Cre-coding region, and a bovine growth hormone polyadenylation cassette. This transgene was injected into (C57BL/6J x SJL/J) hybrid cells. Transgenic founders (line 189) were found to have approximately 80 copies of the transgene and were bred to C57BL/6J mice.