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Pax6-Cre Mice
Catalog Number：C001279
Genetic Background：C57BL/6J
Reproduction：Heterozygote x WT
Strain Description
The Pax6 gene belongs to the Pax gene family and is an evolutionarily conserved gene that encodes a transcription factor. During embryonic development, the Pax6 gene plays an important regulatory role in the morphological development of organs such as the eyes, nervous system, and pancreas. In the development of the eye, the Pax6 gene is one of the main regulatory genes, widely expressed in the neuroectoderm and surface ectoderm. The Pax6 gene is regulated by multiple enhancers located upstream and downstream of the transcription start site, at distances of tens or hundreds of bases. Mutations in the Pax6 gene or its regulatory elements can lead to various eye malformations, such as iris defects, cataracts, and retinal dysplasia. In addition, the Pax6 gene is also associated with diseases such as diabetes and cancer.
This strain was constructed using gene editing technology. The TAA stop codon was replaced with the “P2A-Cre” cassette. The expression pattern of Cre recombinase in these mice is similar to that of the endogenous Pax6 gene. When crossed with mice containing loxP sites, sequence deletion between loxP sites mediated by Cre recombinase occurs in the retina during the early embryonic development of the offspring. The heterozygous Pax6-Cre mice are viable and fertile, while homozygous mice have incomplete eye development.
The TAA stop codon was replaced with the “P2A-Cre” cassette. The expression pattern of Cre recombinase in these mice is similar to that of the endogenous Pax6 gene.
a. Method
The Pax6-Cre mice were bred with Rosa26-LSL-tdTomato mice to generate double heterozygous offspring. Cre-mediated recombination will result in the expression of tdTomato protein in the Cre-positive cells of the offspring. Tissues such as the eyeball, brain, and pancreas were collected from 6-week-old offspring mice and immunofluorescence staining was used to observe the expression of tdTomato protein to determine the activity of Cre recombinase.
b. Genotype
Cre+: Pax6-Cre[KI/+];Rosa26-LSL-tdTomato[CKI/+]
Cre-: Rosa26-LSL-tdTomato[CKI/CKI]
c. Result
1. Expression of Cre recombinase in the ocular tissues
Figure 1. Immunofluorescence staining of the ocular tissues. In Cre+ mice, red fluorescence from tdTomato protein was detected in the retina. There was also some red fluorescence in the cornea, which accumulates in large quantities in corneal epithelial cells. This indicates that there is a significant amount of Cre recombinase-mediated recombination occurring in this location. In contrast, no tdTomato red fluorescence signal was detected in the control group (Cre-) mice, indicating the absence of Cre recombinase.
2. Expression of Cre recombinase in the brain and third ventricle
Figure 2. Immunofluorescence staining of the brain tissues. In Cre+ mice, a small amount of red fluorescence from tdTomato protein was observed in the third and lateral ventricles, indicating a small amount of Cre recombinase expression in these locations. In contrast, no red fluorescence was detected in the control group (Cre-) mice, indicating the absence of Cre recombinase.
3. Expression of Cre recombinase in the pancreas
Figure 3. Immunofluorescence staining of the pancreatic tissues. In Cre+ mice, a small amount of red fluorescence from tdTomato protein was observed in the pancreas, indicating a small amount of Cre recombinase expression in this location. In contrast, no red fluorescence was detected in the control group (Cre-) mice, indicating the absence of Cre recombinase.
d. Summary
In Pax6-Cre mice, the expression of Cre recombinase is mainly located in ocular tissues. At the same time, a small amount of Cre recombinase-mediated recombination can also be detected in some brain and pancreatic tissues. In addition, immunohistochemical results showed that the corneal tissue of the offspring mice was significantly thickened and adhered to the lens, with the anterior chamber defects and disruption of regional retinal epithelial tissue. These phenomena may be caused by off-target effects or toxicity of Cre recombinase (internal validation data. Unpublished). The expression pattern of Cre recombinase in this model is similar to that of the mouse endogenous Pax6 gene, with good tissue specificity.
1. The Cre recombinase gene is located on chromosome 2 in Pax6-Cre mice. Please avoid breeding with gene-edited mice targeting the same chromosome as the Cre mice.
2. Homozygous Pax6-Cre mice have ocular developmental defects. Please maintain the Cre gene as heterozygous when breeding with flox mice.
