B6.129(Cg)-Ret^tm13.1Jmi/SjnJ

Stock number: 029847
Product name: RET-GFP KO
Strain synonyms: Ret-EGFP
Research areas: Neurobiology Research, Research Tools

Description

These Ret-EGFP knock-in/knock-out mice express the EGFP reporter under the control of the endogenous promoter and are useful in studies of neural and renal development.

Detailed description

The targeted Ret gene encodes a receptor tyrosine kinase that is important in neural crest and kidney development. Mutations in this gene have been associated with multiple endocrine neoplasia, Hirschsprung disease, and medullary thyroid carcinoma. These mice carry a knock-in/knock-out allele in which exon 1 is disrupted and the EGFP reporter is expressed from the endogenous Ret locus. Cre recombinase mediated excision of the floxed human RET cDNA which replaced exon 1 resulted in the expression of the EGFP. Homozygous mice exhibit characteristics similar to other knock-out mice, including a perinatal lethal phenotype, renal agenesis and intestinal aganglionosis. EGFP expression in heterozygotes is detected in kidneys, enteric nervous system, testis, dorsal root ganglion, spinal motor neurons, and midbrain dopaminergic neurons of the substantia nigra compacta and the ventral tegmental area. EGFP reporter expression recapitulates the endogenous Ret expression pattern.

Development

A targeting vector containing loxP site flanked human RET (ret proto-oncogene) cDNA and SV40 polyadenylation signal, EGFP, and a FRT site flanked neo cassette, was used to disrupt exon 1 of the endogenous Ret gene. The construct was electroporated into (129X1/SvJ x 129S1/Sv)F1- Kitl⁺-derived R1 embryonic stem (ES) cells. Correctly targeted ES cells were injected into blastocysts. The resulting chimeric male animals were bred to transgenic mice expressing FLP recombinase, on the C57BL/6 genetic background, to excise the FRT site flanked neo cassette (RETfloxEGFP). The mice were bred to beta-actin-Cre recombinase, Tg(ACTB-cre)2Mrt, expressing mice, on the C57BL/6 background, to excise the floxed RET sequence, generating Ret-EGFP mice. The mice were then backcrossed to C57BL/6 for 15 generations. The beta-actin-Cre recombinase transgene was bred out of the line. Upon arrival, sperm was cryopreserved. To establish our live colony, an aliquot of frozen sperm was used to fertilize C57BL/6J oocytes (Stock No. 000664).

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. While the 43 markers throughout the genome suggested a C57BL/6 genetic background, all 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 C57BL/6N genetic background.

Allele

Symbol: Ret^tm13.1Jmi
Name: targeted mutation 13.1, Jeffrey Milbrandt
MGI accession ID: MGI:3691588
Generation method: Targeted
Attributes: Reporter; Null/Knockout
Synonyms: RET^-; RET^EGFP; Ret-EGFP
Marker symbol: Ret
Marker name: ret proto-oncogene
Marker synonyms: CDHF12; CDHR16; c-Ret; HSCR1; MEN2A; MEN2B; MTC1; PTC; RET51; RET9; RET-ELE1
Chromosome: 6
Strain of origin: (129X1/SvJ x 129S1/Sv)F1-Kitl⁺
Expressed genes: GFP,Green Fluorescent Protein,
Site of expression: EGFP is expressed in kidneys, enteric nervous system, testis, dorsal root ganglion, spinal motor neurons, and midbrain dopaminergic neurons of the substantia nigra compacta and the ventral tegmental area.
Molecular note: A loxP site and the human RET (RET9) sequence was inserted with a floxEGFPfrt-neo-frt cassette. The neo was removed by flp mediated recombination. This allele allows EGFP expression upon the cre mediated deletion of floxed cDNA from exon 1. Cre-mediated recombination removed the cDNA and allows for the expression of the reporter gene.