B6(Cg)-Tg(Cd8a-icre/ERT2,-GFP)#Daav/J

Stock number: 038536
Product name: E8I^icreERT2.GFP
Research areas: Immunology, Inflammation and Autoimmunity Research, Research Tools

Description

E8I^icreERT2.GFP transgenic mice express tamoxifen-inducible Cre-recombinase under the direction of the E8I CD8 subunit alpha (Cd8a) locus enhancer, which drives Cre activity in mature CD8+ thymocytes and peripheral CD8+ T cells. The transgenic construct also contains GFP which can be detected by flow cytometry. These mice may be useful for deletion of loxP-flanked sequences in CD8a-expressing cells.

Detailed description

CD8 antigen is a cell surface glycoprotein found on most cytotoxic T lymphocytes that lays an essential role in the immune response. E8I^icreERT2.GFP transgenic mice express tamoxifen-inducible Cre-recombinase under the direction of the E8I CD8 subunit alpha (Cd8a) locus enhancer, which drives Cre activity in mature CD8+ thymocytes and peripheral CD8+ T cells. The transgenic construct also contains GFP which can be detected by flow cytometry. The transgene was found to be hemizygously inserted into chromosome 2 at approximately 2H3-4, as determined by fiber fluorescence in situ hybridization (Immunity, 2021).

Restricted to the cytoplasm, Cre-ERT can only gain access to the nuclear compartment after exposure to tamoxifen. When E8I^icreERT2.GFP transgenic mice are bred with mice containing loxP-flanked sequences, tamoxifen-inducible Cre-mediated recombination will result in deletion of the floxed sequences in the cre-expressing cells of the offspring.

Hemizygous E8I^icreERT2.GFP transgenic mice are viable and fertile, with no overt phenotype. Homozygous mice have not been evaluated to date. The donating laboratory bred these E8I^icreERT2.GFP transgenic mice to Rosa26^LSL.hNGFR knock-in mice (Stock No. 038535) to confirm Cre-activity. Cre-recombinase activity was noted in mature CD8+, but not CD4+ T cells or other cellular populations in the respective progeny. These mice may be useful for deletion of loxP-flanked sequences in CD8a-expressing cells.

Development

The E8I^icreERT2.GFP transgenic construct was designed by inserting a 1.6kb core of the E8I Cd8 locus enhancer region immediately upstream of the CD8 subunit alpha (CD8a) promoter, a tamoxifen inducible codon improved Cre recombinase (iCreERT2) cDNA and an IRES-GFP-polyA cassette downstream of the CD8a promoter. The construct was linearized and microinjected into fertilized C57BL/6 oocytes. Founder mice were bred to C57BL/6 mice for at least one generation to confirm germline transmission. The donating laboratory then bred hemizygous E8I^icreERT2.GFP mice to B6.Cg-Gt(ROSA)26Sor^{tm14(CAG-tdTomato)Hze}/J mice (Stock No. 007914) for at least 15 generations by the donating laboratory. Males hemizygous for the E8I^icreERT2.GFP transgene and wildtype for the Gt(ROSA)26Sor^{tm14(CAG-tdTomato)Hze} allele were used to cryopreserve this mouse line. The donating investigator has indicated that the transgene was found to be hemizygously inserted into chromosome 2 at approximately 2H3-4, as determined by fiber fluorescence in situ hybridization (Immunity, 2021). To establish our live colony, an aliquot of frozen sperm was used to fertilize C57BL/6J (Stock No. 000664) oocytes.

Allele

Symbol: Tg(Cd8a-icre/ERT2,-GFP)#Daav
Name: transgene insertion, Dario AA Vignali
MGI accession ID: MGI:6726258
Generation method: Transgenic
Attributes: Recombinase-expressing; Reporter; Inducible
Synonyms: E8I^CreERT2.GFP
Marker symbol: Tg(Cd8a-icre/ERT2,-GFP)#Daav
Marker name: transgene insertion, Dario AA Vignali
Chromosome: UN
Strain of origin: C57BL/6
Molecular note: The 1.6 kb core of the E8I Cd8 locus enhancer region was inserted in front of the Cd8a promoter, and iCreERT2 cDNA and an IRES-GFP-polyA cassette were inserted after the promoter to generate the transgene construct. Founder information and line numbers were not available. The pound symbol (#) is used when no line is specified and/or lines are pooled.