B6.Cg-Tg(Sox2-flpo)4.2.28Mhem/J

Stock number: 039199
Product name: Sox2-Flp
Strain synonyms: Sox2-FlpO
Research areas: Research Tools

Description

Removal of this mouse colony is imminent. If live mice are needed for your studies, it is advised that they be ordered immediately. After removal, the mice will be available from a cryorecovery.

These Sox2-FlpO transgenic mice express Flpo recombinase under the control of the mouse Sox2 (SRY-box containing gene 2) promoter and may be useful for generating trophoblast-specific conditional mutations.

Detailed description

These transgenic mice express Flpo recombinase under the control of the mouse SRY (sex determining region Y)-box 2 (Sox2) promoter/enhancer construct. The Sox2 promoter/enhancer is the same as the one used in Hayashi et al. 2002 (PMID:14516668). When these transgenic males are bred with mice containing frt-flanked sequences, Flpo-mediated recombination will result in deletion of the frt-flanked sequences in Sox2-expressing tissues in the offspring. Specifically, Flpo recombinase activity is detected in E5.5 epiblast but not in trophoblast cells of the extra-embryonic ectoderm, thus resulting in Flpo recombination in the entire embryo proper but not in placental trophoblast nor visceral endoderm [Radford et al. Nat Commun. 2023 (PMID:36859534)]. These Sox2-FlpO transgenic may be useful for generating trophoblast-specific conditional mutations.

Mice hemizygous for the Sox2-FlpO transgene are viable, fertile, normal in size and do not display any gross physical or behavioral abnormalities. The donating investigator has not attempted to create a homozygous colony and reports breeding through the male germline. Transmission through the female germline has not been tested.

Development

The Sox2-FlpO transgene was created by Dr. Myriam Hemberger [University of Calgary] designed with 13.7 kb of regulatory sequence from the mouse Sox2 locus (SRY-box containing gene 2), a chicken β-actin intron, a Flpo recombinase gene, and a rabbit β-globin poly(A) sequence. The construct was generated by replacing the Cre recombinase gene with the Flpo coding sequence in the original construct used by Hayashi et al. 2002 (PMID: 14516668). This transgene [Radford et al. Nat Commun. 2023 (PMID: 36859534)] was introduced into fertilized C57BL/6 x (DBA x C57BL/6) oocytes. The donating laboratory reported the resulting founder animals from line 4.2.28 were backcrossed to C57BL/6NCrl mice for at least 6 generations prior to sending males to The Jackson Laboratory in 2024 (see SNP note below). Upon arrival, sperm was cryopreserved. To establish our live colony, an aliquot of frozen sperm was used to fertilize C57BL/6NJ oocytes (Stock No. 005304).

The transgene insertion site is not known, the donating investigator reports that the transgene did not integrate into Chromosomes 3, 7, or 8.

In 2024, a 48 SNP (single nucleotide polymorphism) panel analysis, with 43 markers covering all 19 chromosomes and the X chromosome, as well as 5 markers that distinguish between the C57BL/6J and C57BL/6N substrains, was performed on the males sent to The Jackson Laboratory Repository. One of the 43 markers throughout the genome was segregating with DBA on Chromosome 12 (~30 Mb). Also, two of the 5 markers that determine C57BL/6J from C57BL/6N were found to be segregating. These data suggest the mice sent to The Jackson Laboratory Repository were on a mixed C57BL/6N;C57BL/6J genetic background.

Allele

Symbol: Tg(Sox2-flpo)4.2.28Mhem
Name: transgene insertion 4.2.28, Myriam Hemberger
MGI accession ID: MGI:7587778
Generation method: Transgenic
Attributes: Recombinase-expressing
Synonyms: Sox2-Flp; Sox2-FlpO
Marker symbol: Tg(Sox2-flpo)4.2.28Mhem
Marker name: transgene insertion 4.2.28, Myriam Hemberger
Chromosome: UN
Strain of origin: DBA x C57BL/6
Molecular note: This transgene expresses FlpO recombinase under the control of a mouse Sox2 promoter contained in a ~13.7 kb genomic fragment encompassing the Sox2. Two founder lines (1.27 and 4.2.28) were established and used in further study.