B6;C3-Tg(CAG-DsRed,-EGFP)5Gae/J

Stock number: 008605
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.

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 wild-type 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. Upon arrival, mice were bred to C57BL/6J inbred mice (Stock No. 000664) for at least one generation to establish the colony.

Allele

Symbol: Tg(CAG-DsRed,-EGFP)5Gae
Name: transgene insertion 5, Gregory A Elder
MGI accession ID: MGI:3809927
Generation method: Transgenic
Attributes: Reporter
Synonyms: IRG; insulator/red/green
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.