B6.Cg-Tg(CAG-Bgeo,-DsRed*MST)1Nagy/J

Stock number: 006055
Research areas: Research Tools

Description

These Z/RED transgenic mice express beta-galactosidase (lacZ) under the control of the chicken beta actin promoter coupled with the cytomegalovirus (CMV) immediate early enhancer. When crossed with a Cre recombinase-expressing strain, lacZ expression is replaced with red fluorescent protein (DsRed*MST) expression in tissues expressing Cre recombinase. This double reporter system makes it possible to distinguish a lack of reporter expression from a lack of Cre recombinase expression while providing a means to assess Cre excision activity in live animals and cells.
This strain is discontinued, please see the replacement strain: Stock No. 005438.

Detailed description

While mice hemizygous for this Z/RED transgene (on an outbred genetic background, see Stock No. 005438) are reported to be viable and fertile, it has been our experience at The Jackson Laboratory that hemizygous animals are often smaller than littermates and subject to postnatal mortality. Delayed weaning greatly enhances the survival. Although homozygous animals are born, animals have not survived past 5 weeks of age. These transgenic mice express beta-galactosidase (lacZ) under the control of the chicken beta actin promoter coupled with the cytomegalovirus (CMV) immediate early enhancer. When crossed with a Cre recombinase-expressing strain, lacZ expression is replaced with red fluorescent protein (DsRed*MST) expression in tissues expressing Cre recombinase. This double reporter system makes it possible to distinguish a lack of reporter expression from a lack of Cre recombinase expression while providing a means to assess Cre excision activity in live animals and cells.

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

A transgenic construct containing a Red Fluorescent Protein variant (DsRed.MST) gene under the control of the a chicken beta actin promoter coupled with the cytomegalovirus (CMV) immediate early enhancer upstream of a loxP site flanked beta-geo gene, was introduced into 129S6B6F1 derived G4 embryonic stem (ES) cells. ES cell clone containing one copy of the transgene and expressing LacZ was aggregated with ICR outbred tetraploid embryos to generate chimeric mice. The resulting chimeric male animal was bred with an ICR outbred female. Progeny from this cross, that were hemizygous for the transgene, were bred to ICR outbred mice. Upon arrival at The Jackson Laboratory (as Stock No. 005438), some mutant mice were backcrossed to C57BL/6J for at least 5 generations to establish this congenic strain (Stock No. 006055).

Allele

Symbol: Tg(CAG-Bgeo,-DsRed*MST)1Nagy
Name: transgene insertion 1, Andras Nagy
MGI accession ID: MGI:3697095
Generation method: Transgenic
Attributes: Reporter
Marker symbol: Tg(CAG-Bgeo,-DsRed*MST)1Nagy
Marker name: transgene insertion 1, Andras Nagy
Chromosome: UN
Strain of origin: (129S6/SvEvTac x C57BL/6NCrl)F1
Expressed genes: Bgeo,fusion of beta-galactosidase and neomycin phosphotransferase genes,E. coli; RFP,Red Fluorescent Protein,coral
Site of expression: lacZ is expressed in embryonic and adult tissues; when crossed with a cre recombinase-expressing strain, lacZ expression is replaced with Red Fluorescent Protein variant (DsRed.MST) expression
Molecular note: The transgene contains the coding sequence for the DsRed*MST variant red fluorescent protein and a polyadenylation signal downstream of a loxP-flanked lacZ/neomycin resistance fusion gene (Betageo) followed by three polyadenylation signals (STOP sequence); both coding sequences reside downstream of a chicken beta-actin promoter and a cytomegalovirus enhancer. Excision of the lacZ-STOP by Cre recombinase in doubly transgenic ES cells or mice leads to expression of DsRed*MST; use of a ubiquitously expressed cre transgene results in fluorescence of ES cells, embryos and adult mice.
General note: The transgenic ES cell clone 11/C1 was used to generate transgenic mice.

The authors originally identified the red fluorescent protein variant employed in constructing the transgene vector as DsRed.T3; in a later erratum, they corrected this to DsRed-MST, which differs from the former at two amino acid positions (K Vintersten et al. 2005. Genesis 42(3):218).

see MMRRC Nagy ES cell lines: ES cell line G4 with DsRed.MST transgene (http://www.mmrrc.org/strains/11988/011988.html) and ES cell line G4 with Z/red transgene (http://www.mmrrc.org/strains/11987/011987.html) - dlb