B6.C-Epor^{tm1.1(EGFP/icre)Uk}/MdfJ

Stock number: 035702
Product name: EpoRCre , ErGFPcre
Research areas: Developmental Biology Research, Hematological Research, Research Tools

Description

ErGFPcre knock-in/knock-out mice have an EGFP reporter fused to an iCre recombinase cDNA inserted into the 5' UTR of the erythropoietin receptor (Epor) gene. EGFP/iCre is expressed by erythroid progenitors. This strain may be useful as a reporter for lineage tracing and a Cre-lox tool for deletion of floxed sequences in cells in the erythroid lineage.

Detailed description

Epor (erythropoietin receptor) encodes a cytokine receptor involved in the regulation of erythropoiesis. ErGFPcre knock-in/knock-out mice carry an EGFP reporter fused to an iCre recombinase cDNA inserted into the 5' UTR of the Epor gene, in addition, part of Epor exon 2 and exons 3-8 have been deleted. EGFP and iCre are expressed by erythroid progenitor cells. Mice heterozygous for the mutation are viable and fertile, however, homozygous embryos are unable to produce red blood cells and die by E12.5. When crossed with a strain containing a loxP site flanked sequence of interest, offspring are useful for generating Cre-mediated targeted deletions in Epor-expressing tissues. This strain may be useful as an EGFP reporter for lineage tracing and a Cre-lox tool for cells in the erythroid lineage.

Development

The targeting vector, created in the laboratory of Dr. Ursula Klingmuller (German Cancer Research Institute), contains an EGFP reporter fused to codon improved iCre recombinase cDNA inserted into exon 1 of the Epor (erythropoietin receptor) gene. Specifically, the EGFP ATG start site is fused to the Epor 5’ untranslated region.  An FRT-flanked neomycin cassette was inserted to replace parts of exon 2 and exons 3-8. Transient Flp expression removed the neo cassette, leaving a residual intron 3 FRT site. The construct was electroporated into BALB/c -derived BALC/c-I embryonic stem (ES) cells. Correctly targeted ES cells were injected into blastocysts. Chimeric males were crossed to BALB/c females. Dr. Mark Fleming (Children's Hospital Boston) obtained ErGFPCre mice from Dr. Klingmuller and introgressed the allele into C57BL/6J for 22 generations. Upon arrival, mice were bred to C57BL/6J for at least 1 generation to establish the colony.

Allele

Symbol: Epor^{tm1.1(EGFP/icre)Uk}
Name: targeted mutation 1.1, Ursula Klingmuller
MGI accession ID: MGI:3052727
Generation method: Targeted
Attributes: Recombinase-expressing; Reporter; Null/Knockout
Synonyms: Epor^{tm1.1(EGFP/icre)Uk}; EpoRCre; EpoR-iCre; ErGFPcre
Marker symbol: Epor
Marker name: erythropoietin receptor
Marker synonyms: EPO-R
Chromosome: 9
Strain of origin: BALB/cJ
Site of expression: erythroid progenitor cells

Molecular note: An EGFP/icre sequence was inserted into exon 1, replacing the endogenous ATG with the translational start site of the EGFP/icre, yet preserving the last 10 bp of the splice-donor site of exon 1. A FRT flanked neo was inserted downstream to replace parts of exon 2 and exons 3-8. Transient FLP expression excised the neo. Southern blot and multiplex PCR confirmed recombination in heterozygous mice. Immunoblot of FLCs demonstrated green fluorescence in heterozygous and homozygous embryos, with homozygotes showing a 2-fold increase in fluorescence intensity compared to heterozygotes.