STOCK Et(cre)TFC.09Lois/J

Stock number: 024849
Product name: Thy1.2-Cre transgenic line TFC.09
Research areas: Neurobiology Research, Research Tools

Description

The Thy1.2-Cre enhancer trap transgenic mouse line 09 (TFC.09) expresses Cre recombinase sparsely in a small number of cortical progenitor cells during early forebrain development. GFP expression is almost undetectable by fluorescence and it is only transiently expressed in a few stem cells in the embryo. TFC.09 mice allow examination of individual columns and cells, and may be useful for investigating patterns of neural development in the neocortex, as well as for studying cell lineage in mouse brain.

Detailed description

TFC.09 mice have the Thy1.2-Cre enhancer trap transgene (129 bp mouse Thy1.2 minimal promoter and Cre::GFP fusion gene) integrated as a single copy into the seventh intron of the glypican 3 gene on the X chromosome. The expression of Cre and the subsequent recombination events in the TFC.09 line showed no correlation with the expression pattern of the glypican 3 gene. The donating investigator reports that GFP expression is almost undetectable by fluorescence and it is only transiently expressed in a few stem cells in the embryo.

For TFC.09 mice, Cre recombinase is expressed sparsely in a small number of neural progenitor cells during early forebrain development. These neural progenitor cells consist of lineage-related, excitatory neurons and discrete columnar structures that contain both projection neurons and protoplasmic astrocytes that were distributed sparsely through neocortex layers 2-6. When these enhancer trap transgenic mice are bred with mice containing loxP-flanked sequences, Cre-mediated recombination will result in deletion of the floxed sequences in the cre-expressing cells of the double mutant offspring.

Whereas published Gpc3 knockout mice are reported to have partial postnatal lethality, mild craniofacial defects and reproductive defects, the donating investigator reports TFC.09 mice (homozygous females and hemizygous males) are viable and fertile with normal lifespan and no reported abnormalities in behavior or brain structure.

Development

An enhancer trap lentiviral transgenic approach was used by Dr. Carlos Lois (University of Massachusetts Medical School) to generate these TFC.09 mice. The donating investigator reports that the Thy1.2-Cre transgene was designed with a 129 bp mouse Thy1.2 minimal promoter sequence and Cre recombinase::Green Fluorescent Protein fusion gene sequence. The Thy1.2-Cre enhancer trap packaged lentivirus transgene was injected subzonally (under the zona pellucida) into 1-2 cell stage C57BL/6J mouse embryos to produce independent founder lines.

To test expression patterns, transgenic founder animals were bred with floxed reporter mice (Z/EG; same allele as Stock No. 004178) and/or Susan Dymecki's mch/lox/GFP mice (Gt(ROSA)26Sor^tm6Dym). Offspring from founder mouse 09 were found to have sparse Cre expression in a small number of progenitor cells in early forebrain development.

Founder mouse 09 was bred with CD1 wildtype mice to establish the Thy1.2-Cre transgenic line 09 (also called TFC.09). The TFC.09 colony was thereafter maintained by breeding homozygous females with hemizygous males. TFC.09 mice have a single copy of the transgene in intron seven of the glypican 3 locus (Gpc3) on chromosome X. The expression of Cre and the subsequent recombination events in the TFC.09 line showed no correlation with the expression pattern of the glypican 3 gene.

In 2015, hemizygous males on a C57BL/6J;CD1 genetic background with agouti coat color were sent to The Jackson Laboratory Repository. Upon arrival, sperm was cryopreserved. To generate the living colony, an aliquot of the frozen sperm was used to fertilize oocytes from C57BL/6J female mice (Stock No. 000664).

Allele

Symbol: Et(cre)TFC.09Lois
Name: enhancer trap TFC.09, Carlos Lois
MGI accession ID: MGI:5443915
Generation method: Transgenic
Attributes: Recombinase-expressing
Marker symbol: Et(cre)TFC.09Lois
Marker name: enhancer trap TFC.09, Carlos Lois
Chromosome: X
Strain of origin: C57BL/6J
Expressed genes: cre,cre recombinase,bacteriophage P1
Site of expression: Cre recombinase is sparsely expressed in a small number of cortical progenitor cells during early forebrain development.
Molecular note: Injection of a lentiviral vector carrying an enhancer trap detector cassette composed of Cre::GFP fusion gene under control of the mouse Thy1.2 minimal promoter (129 bp) was used to generate several cre lines. These were crossed with Z/EG reporter mice, and the patterns of GFP labeling in the brains of the offspring were examined. One line, TCF.09, displayed a low rate of recombination in a sparse and seemingly random subset of neural precursors during development. A single copy of the transgene integrated into the seventh intron of the glypican-3 gene; recombination activity showed no correlation with endogenous Gpc3 gene expression. The investigator reports that GFP expression is almost undetectable by fluorescence and it is only transiently expressed in a few stem cells in the embryo.