Cdh16-iCre Mice

Catalog Number: C001540

Strain Name: C57BL/6JCya-Cdh16^{em2(IRES-iCre)}/Cya

Genetic Background: C57BL/6JCya

Reproduction: Homozygote x Homozygote/Heterozygote x Heterozygote

Strain Description

The cadherin16 (CDH16) gene encodes a calcium-dependent membrane-associated glycoprotein. It belongs to the cadherin superfamily and is a cell adhesion molecule involved in embryonic development and growth. This protein is exclusively expressed in the kidneys, hence it is also known as kidney-specific calcium-binding protein (ksp-calmodulin). CDH16 plays a crucial role in homotypic cell recognition and contributes to tissue morphogenesis, particularly during the formation of renal tubules in embryonic development. In kidney development, CDH16 is specifically highly expressed in renal tubular epithelial cells of the kidneys and the genitourinary (GU) tract, where it plays an essential role in urine concentration and excretion. In adult mice, the expression of this gene is restricted to renal tubular epithelial cells. Mutations or functional abnormalities in the CDH16 gene may be associated with idiopathic renal tubular acidosis and uric acid nephropathy.

The Cdh16-iCre mouse was generated by inserting an optimized codon-modified Cre recombinase (iCre) gene expression cassette into the endogenous Cdh16 gene of mice, driving its specific expression. The iCre recombinase expression pattern is similar to the endogenous gene, and the mouse Cdh16 gene expression remains unaffected. When the Cdh16-iCre mice are crossed with mice containing loxP sites, the offspring’s renal and genitourinary tract epithelial cells can undergo sequence recombination between loxP sites mediated by Cre recombinase. Compared to Cdh16-Cre mice (catalog number: C001452), this strain exhibits higher Cre recombination efficiency in kidney tissue. However, it’s essential to note that there is an increased risk of Cre recombinase expression leakage in other tissues, including the reproductive system. Therefore, when targeting gene knockout, especially in cases where embryonic or postnatal lethality is a concern, it is advisable to prioritize the Cdh16-Cre mouse model.

Strain Strategy

The "IRES-iCre" cassette was inserted 60~100 bp downstream of the TGA stop codon.

Validation Data

a. Method

Cdh16-iCre mice were crossed with Rosa26-LSL-tdTomato mice, which conditionally express a red fluorescent protein (tdTomato), to generate double-heterozygous offspring. In the offspring, deletion of the loxP-stop-loxP (LSL) cassette by Cre recombinase leads to tdTomato protein expression in Cre-positive cells. When the offspring reach 6 weeks of age, kidney, lung, stomach, uterus, ureter, pancreas, aorta, white adipose tissue, ovaries, testes, and epididymis tissues are collected. Immunofluorescence (IF) analysis is performed to determine the distribution of tdTomato protein. Additionally, kidney tissue is observed for spontaneous fluorescence signals to assess Cre recombinase expression.

b. Group

Cre+: Cdh16-iCre[KI/+];Rosa26-LSL-tdTomato[CKI/+];

Cre-: Rosa26-LSL-tdTomato[CKI/CKI].

c. Result

1) Expression of Cre recombinase in the ureter, stomach, and aorta

Figure 1. Immunofluorescence (IF) detection of tdTomato protein in the ureter, stomach, and aorta. The results indicate partial tdTomato red fluorescence in the ureter epithelial cells, gastric mucosal layer, and aorta of Cre+ mice, demonstrating tdTomato expression mediated by Cre recombinase in these cell types. In contrast, Cre- mice show no detectable Cre recombinase activity in corresponding tissues.

2) Expression of Cre recombinase in the pancreas, lung, and white adipose tissue

Figure 2. Immunofluorescence (IF) detection of tdTomato protein in the pancreas, lung, and white adipose tissue. The results indicate partial red fluorescence signals in Cre+ mouse pancreas, lung alveolar, and bronchial epithelial cells, demonstrating Cre-mediated recombination in these cell types. Additionally, minimal red fluorescence is detected in the perivascular connective tissue of white adipose tissue in Cre+ male mice. In contrast, Cre- mice show almost no Cre recombinase activity in corresponding tissues.

3) Expression of Cre recombinase in testis and epididymis

Figure 3. Immunofluorescence (IF) detection of tdTomato protein in testis and epididymis. The results indicate that there is minimal fluorescence signal in the epididymal ducts and pseudostratified epithelium of the efferent ducts in Cre+ mice, suggesting Cre-mediated recombination in these cell types. However, no significant red fluorescence is detected in the testicular tissue, indicating that Cre recombination did not occur in the testes.

4) Expression of Cre recombinase in the uterus and ovaries

Figure 4. Immunofluorescence (IF) detection of tdTomato protein in the uterus and ovaries. The results indicate abundant red fluorescence signals in the columnar epithelium of the uterus and uterine glands in Cre+ mice, suggesting Cre-mediated recombination in these tissue types. However, no significant red fluorescence is observed in the ovarian tissue, indicating that Cre recombination did not occur in the ovaries.

5) Expression of Cre recombinase in the renal cortex and renal medulla

Figure 5. Fluorescence detection of tdTomato protein in the renal cortex and medulla. The results show orange fluorescence signals in the renal tubular epithelial cells of Cre+ mice, indicating Cre-mediated recombination in these cell types. In contrast, corresponding tissues in Cre- mice exhibit no Cre recombinase activity.

d. Summary

In Cdh16-iCre mice, Cre recombinase expression is primarily concentrated in the adult mouse kidney (renal tubular epithelium) and ureter (epithelial cells). Additionally, recombination signals are observed in the uterus (columnar epithelium), epididymis (pseudostratified epithelial cells), stomach (mucosal layer cells), pancreas (ductal cells, acinar cells, and islet cells), lung (alveolar and bronchial epithelial cells), and aorta (smooth muscle). However, no fluorescence signal is detected in the testes, ovaries, or white adipose tissue. Overall, this model can be used for tissue-specific research targeting renal tubular epithelial cells.

Announcement

The insertion site of the Cre recombinase gene expression cassette in this strain is located on chromosome 8. Please avoid breeding with gene-edited mice targeting genes on the same chromosome as the Cre mouse when conducting mating.