C57BL/6-Gt(ROSA)26Sor^{tm2(CAG-Egfr*L860R)Rnem}/J

Stock number: 038454
Product name: Egfr^L860R
Strain synonyms: Egfr^LSL-L860R
Research areas: Cancer Research, Research Tools

Description

Egfr^L860R mice harbor a floxed stop cassette followed by an L860R mutation in the epidermal growth factor receptor (Egfr) gene, knocked-into the Gt(ROSA)26Sor locus. These mice also express mCerulean3 fluorescent protein. The L860R mutation in mice corresponds to the human L858R mutation. These mice may be useful as a reporter strain as well as for studying the effects of the Egfr^L860R mutation in cre-expressing tissues, specifically as it relates to lung cancer pathogenesis.

Note that the donating laboratory has also made a Cre-inducible Egfr^del19 mouse line available, Stock No. 038452.

Detailed description

Epidermal growth factor receptor (EGFR) is a member of the receptor tyrosine kinase family and involved in the regulation of epithelial cell growth and maintenance. Mutations in the Egfr gene have been associated lung cancers, specifically non-small cell lung cancers. The most common Egfr mutations in human patients are L858R missense mutations and in-frame exon 19 deletions. These Egfr^L860R knock-in mice have a stop cassette flanked by two loxP sites inserted into intron 1 of the Gt(ROSA)26Sor locus. The murine L860R mutation corresponds to the human L858R mutation. When bred to mice that express tissue-specific Cre recombinase, resulting offspring will have overexpression of the Egfr^L860R mutant in cre-expressing tissues. These mice will also express mCerulean3 fluorescent protein after Cre-mediated recombination.

Homozygous Egfr^L860R mice are viable and fertile, with no overt phenotype. The donating laboratory crossed these Egfr^L860R knock-in mice to p53^LoxP mice (Stock No. 008462) and the resulting progeny were exposed to an adeno-Cre virus (AdCre) via intratracheal administration. Approximately 8-14 weeks after AdCre exposure, hyperplasias, atypical adenomatous hyperplasias (AAH), adenomas, and multifocal adenocarcinomas were noted in all Egfr^L860R heterozygous mice. mCerulean3 (blue) fluorescence is detectable in tumor cells, after Cre-mediated recombination, by direct fluorescence. These Egfr^L860R knock-in mice may be useful for studying lung cancer onset and progression as well as potential lung cancer therapeutics.

Note that the the donating laboratory has also made a Cre-inducible Egfr^del19 mouse line available, Stock No. 038452.

Development

The Egfr^L860R knock-in allele was generated by insertion of murine epidermal growth factor receptor (Egfr) cDNA carrying the L860R mutation, into the Gt(ROSA)26Sor locus. The targeting cassette includes (from 5’ to 3’) a CMV-IE enhancer/chicken beta-actin/rabbit beta-globin hybrid promoter (CAG), a loxP-flanked STOP cassette including neomycin sequence, Egfr mutant cDNA (L860R mutation), mCerulean3 (mC3) sequence, a woodchuck hepatitis virus post-transcriptional regulatory element (WPRE; to enhance the mRNA transcript stability), and polyA signal. This targeting vector was inserted into intron 1 of the Gt(ROSA)26Sor locus. The construct was electroporated into C57BL/6N-A^tm1Brd-derived JM8.A3 embryonic stem (ES) cells and correctly targeted ES cells were injected into recipient blastocysts. Correctly targeted ES cells were injected into blastocysts. The resulting Egfr^L860R knock-in mice were backcrossed to C57BL/6J for at least 8 generations by the donating laboratory. 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).

Allele

Symbol: Gt(ROSA)26Sor^{tm2(CAG-Egfr*L860R)Rnem}
Name: targeted mutation 2, Raphael A Nemenoff
MGI accession ID: MGI:7545201
Generation method: Targeted
Attributes: Conditional ready (e.g. floxed); Reporter; Inserted expressed sequence; Humanized sequence
Synonyms: Egfr^L860R
Marker symbol: Gt(ROSA)26Sor
Marker name: gene trap ROSA 26, Philippe Soriano
Marker synonyms: beta geo; Gtrgeo26; Gtrosa26; R26; ROSA26; SETD5-AS1; Thumpd3as1
Chromosome: 6
Strain of origin: C57BL/6N-A^tm1Brd
Molecular note: The targeting cassette includes (from 5' to 3') a CMV-IE enhancer/chicken beta-actin/rabbit beta-globin hybrid promoter (CAG), a loxP-flanked STOP cassette including neomycin sequence, Egfr mutant cDNA (L860R mutation), mCerulean3 (mC3) sequence, a woodchuck hepatitis virus post-transcriptional regulatory element (WPRE; to enhance the mRNA transcript stability), and polyA signal. This targeting vector was inserted into intron 1 of the Gt(ROSA)26Sor locus. The murine L860R mutation corresponds to the human L858R mutation.