The inducible KPC:APC mouse model of KRAS mutated colorectal cancer combines the oncogenic conditional KrasG12D allele, the conditional Apcf allele and a tamoxifen inducible Cre recombinase (CDX2-Cre-ERT2) with cre expression in adult epithelium of the distal intestinal tract. Mice develop malignant colonic tumors 25-30 days post tamoxifen induction.
Dr. Radhashree Maitra, Albert Einstein College of Medicine
Dr. Sanjay Goel, Albert Einstein College of Medicine
Genetic Background | Generation |
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000664 C57BL/6J |
?+pN1
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Allele Type | Gene Symbol | Gene Name |
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Targeted (Conditional ready (e.g. floxed), No functional change) | Kras | Kirsten rat sarcoma viral oncogene homolog |
Allele Type |
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Transgenic (Recombinase-expressing, Inducible) |
Allele Type | Gene Symbol | Gene Name |
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Targeted (Conditional ready (e.g. floxed), Hypomorph) | Apc | adenomatosis polyposis coli |
Starting at:
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510.00 Domestic price for breeder pair |
KPC:APC is an inducible mouse model of KRAS mutated colorectal cancer. The model combines a floxed KrasG12D allele that carries a point mutation (G12D) in; the Kirsten rat sarcoma viral oncogene homolog (Kras) gene whose expression is blocked by the presence of a loxP-flanked stop codon, an Apc (APC, WNT signaling pathway regulator) allele with floxed exon 14, and a tamoxifen inducible Cre recombinase (CDX2-Cre-ERT2) with a human caudal type homeo box 2 (CDX2) promoter/enhancer sequence directing expression of CreERT2 fusion gene (a Cre recombinase fused to a human estrogen receptor ligand binding domain). Restricted to the cytoplasm, Cre-ERT2 can only gain access to the nuclear compartment after exposure to tamoxifen. Cre expression is directed to epithelium of the distal ileum and cecum, and throughout the colon from the crypt base to the luminal surface. Mice heterozygous for Kras, homozygous for Apc and hemizygous for CDX2-Cre-ERT2 are viable and fertile. Please note that in the homozygous state Krastm4Tyj is embryonic lethal. The donating investigator reports that cre expression is leaky in 10% of mice. Following tamoxifen induction, KPC:APC mice develop malignant colonic tumors with within 25-30 days (tamoxifen dose .1 mg/20 g weight). Extensive inflammation with multiple small tumors is observed in the cecum, ascending and transverse colon, and large bowel. Histological and molecular analysis of tumors indicates that they resemble human colorectal carcinoma. Mice live an average of 165 days, dying of cachexia and rectal bleeding. Untreated mice live an average 2 years, 10% of untreated mice develop rectal prolapse around 165 days, subsequently dying of cachexia and rectal bleeding.
For the Krastm4Tyj allele, a targeting vector was designed to place a G12D point mutation in exon 1 of the Kras gene on Chromosome 6 and a loxP-flanked STOP element upstream of the mutation. The STOP element incorporates a PGK-puromycin selection cassette at the 5' end in an opposite directional orientation. The stop cassette prevents the expression of mutant KRAS until it is removed by cre-mediated recombination of the loxP sites, thus allowing expression of oncogenic Kras. The construct was electroporated into 129S4/SvJae-derived J1 embryonic stem (ES) cells. The resulting chimeric animals were crossed to C57BL/6J and offspring were backcrossed to C57BL/6J for more than 10 generations.
For the Apctm1Tno allele (also known as Apcfl or Apc580S), the targeting construct contains a loxP site inserted into intron 13 and a PGK neomycin cassette followed by a second loxP site inserted in to intron 14 of the Apc gene on Chromosome 18. Cre-mediated recombination results in deletion of exon 14 rsulting in a frameshift silent mutation at codon 580. The construct was electroporated into 129S4/SvJae-derived J1 embryonic stem (ES) cells. Correctly targeted ES cells were injected into blastocysts. The resulting chimeric animals were crossed to C57BL/6J and offspring were backcrossed to C57BL/6J for 20 generations.
The CDX2-CreERT2 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 creERT2 fusion gene (a Cre recombinase fused to a human estrogen receptor ligand binding domain), and a bovine growth hormone polyadenylation cassette. This transgene was injected into (C57BL/6J x SJL/J) hybrid cells. Transgenic mice from founder line 752 were bred to C57BL/6J mice and offspring were crossed to C57BL/6J for at least 10 generations.
Mice homozygous for Apctm1Tno and hemizygous for Tg(CDX2-cre/ERT2)752Erf on the C57BL/6J genetic background were imported from Dr. Radhashree Maitra (Laboratory of Dr. Sanjay Goel, Albert Einstein College of Medicine) and combined with B6.129S4-Krastm4Tyj/J (Stock 008179) to establish the triple mutant KPC:APC colony.
Expressed Gene | cre/ERT2, Cre recombinase and estrogen receptor 1 (human) fusion gene, |
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Site of Expression | Upon tamoxifen administration, cre activity was detected in the distal ileal, cecal, colonic, and rectal epithelium. |
Site of Expression |
Allele Name | targeted mutation 4, Tyler Jacks |
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Allele Type | Targeted (Conditional ready (e.g. floxed), No functional change) |
Allele Synonym(s) | caKRas; KR; K-Ras(G12D)fl; KrasG12D; K-RasL; KrasLox; K-rasLSL; KrasLSL-G12D; Kras2tm4Tyj; Kras2tm14Tyj; K-RasG12D; Lox-Stop-Lox-KrasG12D; LSL-Kras G12D; LSL-K-ras G12D; LSL-KrasG12D; LSL-K-rasG12D; LSL-KrasG12D |
Gene Symbol and Name | Kras, Kirsten rat sarcoma viral oncogene homolog |
Gene Synonym(s) | |
Strain of Origin | 129S4/SvJae |
Chromosome | 6 |
Molecular Note | By homologous recombination in ES cells, the Kras2 locus was targeted with a cassette containing an oncogenic form of the KRAS2 protein in which the glycine at position 12 had been substituted with a an aspartic acid. A loxP flanked stop codon was included upstream of the inserted Kras2 sequence, such that the mutant transcript would be expressed only after cre-mediated recombination. |
Mutations Made By | Dr. Tyler Jacks, Massachusetts Institute of Technology |
Allele Name | transgene insertion 752, Eric Fearon |
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Allele Type | Transgenic (Recombinase-expressing, Inducible) |
Allele Synonym(s) | CDX2-creERT2; CDX2P9.5-NLSCre |
Gene Symbol and Name | Tg(CDX2-cre/ERT2)752Erf, transgene insertion 752, Eric Fearon |
Gene Synonym(s) | |
Promoter | CDX2, caudal type homeobox 2, human |
Expressed Gene | cre/ERT2, Cre recombinase and estrogen receptor 1 (human) fusion gene, |
Site of Expression | Upon tamoxifen administration, cre activity was detected in the distal ileal, cecal, colonic, and rectal epithelium. |
Strain of Origin | (C57BL/6J x SJL/J) |
Chromosome | UN |
Molecular Note | The 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 creERT2 fusion gene (a Cre recombinase fused to a human estrogen receptor ligand binding domain), and a bovine growth hormone polyadenylation cassette. This transgene was injected into (C57BL/6J x SJL/J) hybrid cells. Transgenic mice from founder line 752 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 at least 4 generations. |
Allele Name | targeted mutation 1, Tetsuo Noda |
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Allele Type | Targeted (Conditional ready (e.g. floxed), Hypomorph) |
Allele Synonym(s) | 580S; Apc580S flox; Apc580s; Apcf; Apcfl; ApcloxP; Apclx |
Gene Symbol and Name | Apc, adenomatosis polyposis coli |
Gene Synonym(s) | |
Strain of Origin | 129S4/SvJae |
Chromosome | 18 |
Molecular Note | One loxP site was inserted into intron 13 and the other, with a PGK-neo cassette, into intron 14. Northern blot analysis revealed that RNA expression in the intestinal tract of homozygous mutants was about 30% of that in wild-type mice. Protein expression in the colon of homozygotes by immunohistochemistry was indistinguishable from that of wild-type mice. Western blot analysis of lysates from mouse embryo fibroblasts showed reduced expression of the protein. |
The strain is maintained as heterozygous for Krastm4Tyj, homozygous for Apctm1Tno and hemizygous for Tg(CDX2-cre/ERT2)752Erf. In the homozygous state, Krastm4Tyj is embryonic lethal.
When using the KPC:APC mouse strain in a publication, please cite the originating article(s) and include JAX stock #035169 in your Materials and Methods section.
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