B6.129S6(SJL)-Gt(ROSA)26Sor^{tm2.1(mix1b-mCherry)Mgn}/Mmjax

Stock number: 022626
Research areas: Research Tools

Description

Mice harboring the pR26-228 AR8-TA-mCherry reporter express mCherry in cells and tissues that receive SMAD2/3 mediated signaling induced by Nodal/Activin. This strain allows live monitoring of SMAD2/3-mediated signaling events seen in embryonic development as well as during regeneration and homeostasis in adults.

Detailed description

Mice harboring the pR26-228 AR8-TA-mCherry reporter are viable and fertile, with expression of mCherry under the control of the activin response element from the Xenopus laevis mix1b (Mix.2) promoter. The red fluorescent protein, mCherry, is expressed in cells and tissues that receive SMAD2/3 mediated signaling induced by Nodal/Activin. The Nodal signal transduction pathway is involved in mesoendoderm induction, patterning of the nervous system, and determination of dorsal- ventral axis in vertebrate embryos. This strain allows live monitoring of SMAD2/3-mediated signaling events seen in particular lineages and stages in embryonic development as well as during regeneration and homeostasis in adults. Additionally, it allows FACS-based isolation of responding cells.

Development

Using the ROSA26^LCA or Loxed Cassette Acceptor allele (Gt(ROSA)26Sor ^tm1Mgn), which contains a loxP-flanked (lox71, lox2272) selection cassette in the ROSA26 promoter, a donor cassette is inserted into the acceptor allele via recombinase mediated cassette exchange (RMCE). The donor cassette or signaling sentinel construct includes a frt-flanked pgk-hygromycin and an activin response element (AR8) from the Xenopus laevis mix1b reporter fused to a TATA-mCherry reporter, which replaced the ROSA26 promoter sequence (-4 kb to -228 bp).

The construct was electroporated into 129S6/SvEvTac-derived TL1 ES cells. Correctly targeted ES cells were injected into blastocysts from C57BL/6J mice. Offspring were bred with B6;SJL-Tg(ACTFLPe)9205Dym/J transgenic mice to delete the pgk-hygromycin cassette. The donating investigator reported that the mice were backcrossed to C57BL/6J mice for 7 generations prior to sending to MMRRC at JAX.

Allele

Symbol: Gt(ROSA)26Sor^{tm2.1(mix1b-mCherry)Mgn}
Name: targeted mutation 2.1, Mark A Magnussen
MGI accession ID: MGI:5476468
Generation method: Targeted
Marker symbol: Gt(ROSA)26Sor
Marker name: gene trap ROSA 26, Philippe Soriano
Chromosome: 6
Strain of origin: 129S6/SvEvTac
Expressed genes: RFP,Red Fluorescent Protein,coral
Site of expression: Red fluorescent protein, mCherry, is expressed in cells and tissues involved in the Nodal signal transduction pathway (mesoendoderm induction, patterning of the nervous system, and determination of dorsal- ventral axis in vertebrate embryos).
Molecular note: This allele was created by RMCE in Gt(ROSA)26Sor^tm1Mgn. The original selections cassettes (puromycin N-acetyltransferase and a truncated form of HSV1 thymidine kinase and EM7-driven neomycin resistance) were replaced by a cassette composed of ROSA26 upstream sequence deleted from the start codon to -228, 8 copies of the 50-bp activin response element (ARE) from the Xenopus laevis Mix1b promoter controlling expression of the mCherry reporter. An upstream FLP flanked hygromycin selection cassette was subsequently removed by flp recombinase.
General note: This allele was generate from Gt(ROSA)26Sor^tm1Mgn.