B6.Cg-Tg(CAG-DsRed,-EGFP)5Gae/J

Stock number: 008705
Strain synonyms: IRG
Research areas: Neurobiology Research, Research Tools

Description

These IRG transgenic mice are a double-fluorescent, Cre-reporter strain; with widespread expression of red fluorescence prior to Cre recombinase exposure, and green fluorescence following cre-mediated recombination in a pattern determined by cre expression, and should provide a versatile tool for analyzing complex cellular relationships in a wide variety of tissues.

Detailed description

Hemizygous IRG transgenic mice are viable and fertile, with widespread expression of a loxP-flanked optimized red fluorescent protein variant (DsRed-Express) directed to embryonic and adult tissues by the CAG promoter prior to exposure to Cre recombinase. When bred to cre-expressing mice, the resulting offspring have the DsRed-Express cassette deleted in the cre-expressing tissue(s), allowing expression of the enhanced green fluorescent protein (EGFP) cassette located just downstream. These IRG transgenic mice are a double-fluorescent, Cre-reporter strain; with widespread expression of red fluorescence prior to Cre recombinase exposure, and green fluorescence following cre-mediated recombination in a pattern determined by cre expression, and should provide a versatile tool for analyzing complex cellular relationships in a wide variety of tissues.

For example, when using IRG transgenic mice along with Nestin-Cre mice (see Stock No. 003771), red and green native fluorescence can be imaged simultaneously in thick tissue sections by confocal microscopy; thus allowing for analysis of complex reconstructions suitable for studying neuronal morphologies as well as neurovascular interactions in brain.

In an attempt to offer alleles on well-characterized or multiple genetic backgrounds, alleles are frequently moved to a genetic background different from that on which an allele was first characterized. It should be noted that the phenotype could vary from that originally described. We will modify the strain description if necessary as published results become available.

Development

The CCAG-R/G expression vector was designed with (from 5' to 3') a Human cytomegalovirus immediate early enhancer and chicken beta-actin/rabbit beta-globin hybrid promoter (CAG), a loxP site, a DsRed-Express protein sequence followed by three SV40 polyadenylation signals (DsRed-Express (Clontech) is a red fluorescent protein tetramer with improved solubility and fluorescence detection), a second loxP site, an enhanced green fluorescent protein (EGFP) sequence itself followed by a rabbit beta-globin polyadenylation signal. To minimize integration site effects and possible promoter interference, the CCAG-R/S expression vector was flanked on both sides with two paired copies of anti-sense oriented 5'-HS4 insulator sequences from the chicken beta-globin gene; generating the final "insulator/red/green" targeting vector (pIRG). The donating investigator confirms that this 9.4 kb transgene was injected into fertilized oocytes from B6C3F1 hybrid mice. Founder mice were bred to C57BL/6 wildtype mice to generate IRG line 5 (estimated to contain seven copies of the transgene). These IRG mice were maintained on a mixed C57BL/6 and C3H genetic background by breeding hemizygotes with C57BL/6 or B6C3 hybrid mice for many generations prior to arrival at The Jackson Laboratory (as Stock No. 008605). Upon arrival, some mice were additionally backcrossed to C57BL/6J inbred mice (Stock No. 000664) to generate this congenic strain (Stock No. 008705).

Allele

Symbol: Tg(CAG-DsRed,-EGFP)5Gae
Name: transgene insertion 5, Gregory A Elder
MGI accession ID: MGI:3809927
Generation method: Transgenic
Attributes: Reporter
Marker symbol: Tg(CAG-DsRed,-EGFP)5Gae
Marker name: transgene insertion 5, Gregory A Elder
Chromosome: UN
Strain of origin: (C57BL/6 x C3H)F1
Expressed genes: GFP,Green Fluorescent Protein,; RFP,Red Fluorescent Protein,coral
Site of expression: Widespread expression of red fluorescent protein is observed; following cre-mediated recombination, GFP is expressed.
Molecular note: The CCAG-R/G expression vector was designed with (from 5' to 3') a Human cytomegalovirus immediate early enhancer and chicken beta-actin/rabbit beta-globin hybrid promoter (CAG), a loxP site, a DsRed-Express protein sequence followed by three SV40 polyadenylation signals (DsRed-Express (Clontech) is a red fluorescent protein tetramer with improved solubility and fluorescence detection), a second loxP site, an enhanced green fluorescent protein (EGFP) sequence itself followed by a rabbit beta-globin polyadenylation signal. To minimize integration site effects and possible promoter interference, the CCAG-R/G expression vector was flanked on both sides with two paired copies of anti-sense oriented 5'-HS4 insulator sequences from the chicken beta-globin gene; generating the final "insulator/red/green" targeting vector (pIRG). Line 5 was established and has an estimated transgene copy number of 7. Embryonic and adult tissues exhibit widespread red fluorescent protein expression in the absence of cre recombinase.