Spo11-eGFP-Cre transgenic mice have the mouse Spo11 (SPO11 meiotic protein covalently bound to DSB) gene promoter driving Cre recombinase expression in spermatocytes that have initiated meiosis. They are suitable for generating tissue specific-targeted mutants in studies of meiotic prophase I chromosomes.
Paula Cohen, Cornell University
The Spo11 gene encodes a subunit of the topoisomerase 6 complex and is essential for the DNA double-strand breaks required for meiotic recombination. These Spo11-Cre mice, also called Spo11-eGFP-Cre, express Cre recombinase and EGFP under the control of the mouse Spo11 (SPO11 meiotic protein covalently bound to DSB) gene promoter. Cre recombinase expression is detected in spermatocytes that have initiated meiosis, as early as postnatal day 10. GFP expression (by immunohistochemistry) is detected in spermatocytes. When crossed with a strain containing loxP site flanked sequence of interest, Cre-mediated recombination results in deletion of the targeted gene in spermatocytes. Mice homozygous for this Spo11-eGFP-Cre transgene are viable and fertile.
The mouse bacterial artificial chromosome (BAC) RP23-20N4 containing the entire Spo11 gene, was modified by inserting an IRES-EGFP-Cre cassette and a frt-flanked neo cassette. DNA from a correctly modified BAC clone containing the modified Spo11 gene and approximately 5kb of upstream sequence, was used as the source for the Spo11-eGFP-Cre transgene. The transgene gene was electroporated into unspecified 129-derived embryonic stem (ES) cells. Correctly targeted ES cells were injected into blastocysts. The resulting chimeric animals were tested for germline transmission. The mice were crossed to unspecified Actb-FLPe mice (on an unconfirmed background) with the intention of removing the frt-flanked neo cassette (see additional details below). The colony was then backcrossed to C57BL/6 for two generations (the Actb-FLPe was bred out), and then sent to The Jackson Laboratory in 2019. Upon arrival, sperm was cryopreserved. To establish our live colony, an aliquot of frozen sperm was used to fertilize C57BL/6J oocytes (Stock No. 000664). In 2019, this mouse line was discovered to have a neo cassette that segregated with the Cre sequences. In 2020, further sequencing confirmed the transgene had retained the frt-flanked neo and that it was a 34 bp minimal frt site at the 5' end and a 48 bp frt site at the 3' end.
|Allele Name||transgene insertion 1, Robert S Weiss|
|Allele Type||Transgenic (Recombinase-expressing)|
|Allele Synonym(s)||Spo11-cre; Spo11-eGFP-Cre|
|Gene Symbol and Name||Tg(Spo11-cre)1Rsw, transgene insertion 1, Robert S Weiss|
|Strain of Origin||Not Specified|
|General Note||The initial report indicated that the FRT-flanked neomycin cassette had been removed, however, further sequencing confirmed the transgene had retained the FRT-flanked neo and that it was a 34 bp minimal frt site at the 5' end and a 48 bp frt site at the 3' end.|
|Molecular Note||An IRES-EGFP-cre cassette and FRT-flanked neo marker were inserted into a BAC containing the Spo11 gene. A fragment containing the Spo11 sequence with 5 kb of upstream sequence, the IRES-EGFP-cre cassette and neo marker was isolated from the modified BAC and transfected into ES cells. Targeted ES cells were injected into blastocysts to generate transgenic animals. Founder information and line numbers are not available.|
When maintaining a live colony, these mice can be bred as homozygotes.
When using the Spo11-cre, Spo11-eGFP-Cre mouse strain in a publication, please cite the originating article(s) and include JAX stock #032646 in your Materials and Methods section.