B6.FVB-Tg(Stra8-icre)1Reb/LguJ

Stock number: 017490
Product name: Stra8-iCre
Research areas: Reproductive Biology Research, Research Tools

Description

These Stra8-cre transgenic mice have expression of Cre recombinase (iCre) directed by the Stra8 genomic promoter fragment, and may be useful in generating conditional knockouts in postnatal, premeiotic, male germ cells for studying spermatogenesis.

Of note, the same Stra8-cre transgene is also available on a mixed genetic background as Stock No. 008208.

Detailed description

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. This is the case for Stock No. 017490. It should be noted that the phenotype could vary from that originally described for Stock No. 008208. We will modify the strain description if necessary as published results become available.

Hemizygous Stra8-cre transgenic mice are viable and fertile, with expression of an optimized variant of Cre recombinase (iCre) directed by the 1.4 kb mouse Stra8 (stimulated by retinoic acid gene 8) genomic promoter fragment. The Donating Investigator has not attempted to make the congenic B6 strain homozygous.

Postnatal Cre-recombinase expression is first observed in testes at postnatal day (P)3 (early-stage spermatogonia), increases out to P7 (pre-leptotene-stage spermatocytes), and is not detected in other tissues examined (including ovaries). In addition, no cre expression was reported in male or female embryos [Sadate-Ngatchou et al. 2008 Genesis 46:738]. See additional links below for more information on expression in male and female embryos and adults.

When Stra8-cre transgenic males are bred with female mice containing a loxP-flanked sequence, Cre-mediated recombination will result in deletion of the floxed sequence, specifically during these stages of spermatogenesis. These Stra8-cre transgenic mice may be useful in generating conditional knockouts in postnatal, premeiotic, male germ cells for studying spermatogenesis.

If the recombinase activity pattern of this transgene is further characterized by the Genetic Resource Science group at The Jackson Laboratory, such findings will be reported on the Mouse Genome Informatics (MGI) Transgene Detail entry (Tg(Stra8-icre)1Reb). In general, expression of the endogenous mouse gene may be found searching the MGI Recombinase Activity and MGI Gene Expression + Recombinase Activity Comparison Matrix.

Development

The 3.1 kb Stra8.iCre transgene was designed with the 1.4 kb mouse Stra8 (mouse stimulated by retinoic acid gene 8) genomic promoter fragment (containing the entire promoter region from -1400 to +7), an SV40 splice donor/splice acceptor region, an optimized variant of Cre recombinase (iCre; improved with mammalian codon usage, removed putative cryptic splce sites, altered stop codon, and reduced CpG content to limit the chances of epigenetic silencing in mammals), and an SV40 polyA signal. The transgene was microinjected into the pronucleus of fertilized FVB eggs. The single founder male exhibiting germline expression of the transgene was generated. The mice were then backcrossed to C57BL/6J for at least 8 generations. Upon arrival, the mice were bred to C57BL/6J inbred mice (Stock No. 000664) to establish the colony.

Allele

Symbol: Tg(Stra8-icre)1Reb
Name: transgene insertion 1, Robert E Braun
MGI accession ID: MGI:3779079
Generation method: Transgenic
Attributes: Recombinase-expressing
Marker symbol: Tg(Stra8-icre)1Reb
Marker name: transgene insertion 1, Robert E Braun
Chromosome: UN
Strain of origin: FVB/NJ
Expressed genes: cre,cre recombinase,bacteriophage P1
Site of expression: Postnatal Cre-recombinase expression is first observed in testes at postnatal day (P)3 (early-stage spermatogonia), increases out to P7 (pre-leptotene-stage spermatocytes), and is not detected in other tissues examined (including ovaries). In addition, no cre expression is reported in male or female embryos.
Molecular note: A 1.4Kb promoter fragment of Stra8 was inserted upstream of the 1.26Kb improved Cre recombinase coding sequence, separated by SV40 splice donor/splice acceptor sequence. The Stra8 promoter region used was -1400 to +7, inserted into the plasmid vector with AvrII and XhoI recognition sites, respectively.