B6.Cg-Tg(Gfap-cre)73.12Mvs/J

Stock number: 012886
Research areas: Developmental Biology Research, Neurobiology Research, Research Tools

Description

This strain is undergoing recovery from cryopreserved stocks.

GFAP-Cre transgenic mice from founder line 73.12 have Cre recombinase expression directed by the mouse glial fibrillary acidic protein promoter. Cre expression is observed in astrocytes in the brain and spinal cord, as well as postnatal and adult GFAP-expressing neural stem cells and their progeny in the brain.

Detailed description

Mice hemizygous for the GFAP-cre transgene are viable and fertile, with a mouse glial fibrillary acidic protein (mGfap) promoter sequence directing expression of Cre recombinase. Specifically, Cre recombinase activity (as defined by expression of a floxed-STOP reporter gene) is targeted to most astrocytes throughout healthy brain and spinal cord tissues, and to essentially all astrocytes following central nervous system (CNS) injury.

In contrast to GFAP-Cre line 77.6 (Stock No. 024098), these GFAP-Cre line 73.12 mice (Stock No. 012886) are reported to have Cre recombinase activity in essentially all adult neural stem cells (and their progeny) from the hippocampal dentate gyrus and subventricular zone. This includes dentate gyrus granule neurons and their mossy fiber axon projections into the CA3 region of the hippocampus. In addition, GFAP-Cre line 73.12 mice exhibit Cre recombinase activity in some hippocampal pyramidal neurons and cerebellar granule neurons (less than 5%), and scattered neurons in the midbrain (less than 0.5%): this is attributed to radial cell progenitors that begin to express Gfap at later developmental stages in postnatal mice when the last-born neurons are generated. Additionally, the donating investigator reports GFAP-Cre lines 73.12 and 77.6 have cre expression in the male germline, and suggests breeding GFAP-Cre females with floxed males for Cre-lox experiments.

When GFAP-Cre line 73.12 mice are bred with mice containing a loxP-flanked sequence, Cre-mediated recombination is expected to result in deletion of the floxed sequences in the Cre recombinase-expressing tissues of the offspring. These GFAP-Cre line 73.12 mice may be useful for studying astrocytes in the brain and spinal cord, as well as postnatal and adult GFAP-expressing neural stem cells and their progeny in the brain.

Development

The GFAP-Cre transgene was designed with the entire mouse glial fibrillary acidic protein gene (Gfap) sequences directing expression of Cre recombinase. The construct has a small fragment of the Gfap first exon removed to prevent GFAP expression from the transgene. The transgene was microinjected into fertilized (BALB/c x C57BL/6NHsd)F1 oocytes. Transgenic founders were bred to C57BL/6 mice, and founder line 73.12 was identified. The GFAP-Cre line 73.12 colony was backcrossed to C57BL/6 animals (see SNP note below) for at least 14 generations, and then sent to The Jackson Laboratory Repository in 2010. Upon arrival, males were used to cryopreserve sperm. To establish the living mouse colony, an aliquot of the frozen sperm was used to fertilize oocytes from C57BL/6J inbred mice (Stock No. 000664).

In 2010, a 32 SNP (single nucleotide polymorphism) panel analysis, with 27 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 rederived living colony at The Jackson Laboratory Repository. While the 27 markers throughout the genome suggested a C57BL/6 genetic background, all 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 C57BL/6N genetic background.
In 2019, our live colony was rederived using cryopreserved sperm (originally frozen in 2010) to fertilize C57BL/6J oocytes. The resulting first generation rederived living colony was segregating for the markers that determine C57BL/6J from C57BL/6N. This is expected and supports the previous SNP results.

Allele

Symbol: Tg(Gfap-cre)73.12Mvs
Name: transgene insertion 73.12, Michael V Sofroniew
MGI accession ID: MGI:3522215
Generation method: Transgenic
Attributes: Recombinase-expressing
Marker symbol: Tg(Gfap-cre)73.12Mvs
Marker name: transgene insertion 73.12, Michael V Sofroniew
Chromosome: UN
Strain of origin: (BALB/c x C57BL/6NHsd)F1
Expressed genes: cre,cre recombinase,bacteriophage P1
Site of expression: Cre recombinase activity is observed in essentially all adult neural stem cells and their progeny in the hippocampal dentate gyrus and subventricular zone. In addition, some hippocampal pyramidal neurons and cerebellar granule neurons (less than 5%) and scattered neurons in the midbrain (less than 0.5%) also exhibit activity.
Molecular note: The bacterial Cre recombinase gene was inserted into the first exon of an expression cassette (clone 445) that contains all the introns, promoter regulatory elements, exons, and 2.5 kb of 5' and 2 kb of 3' flanking DNA of the astroglia-specific mouse glial fibrillary acidic protein gene. GFAP is not expressed from the transgene due to deletion of part of exon 1.