H11-Myh6-iCre Mouse

H11-Myh6-iCre mice were crossed 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 heart, lungs, kidneys, skeletal muscle, uterus, and testes were collected from 6-week-old offspring mice and immunofluorescence staining was used to detect the distribution of tdTomato protein signals to determine the expression of Cre recombinase.

Cre+: H11-Myh6-iCre[KI/+];Rosa26-LSL-tdTomato[CKI/+]

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

In Cre+ mice, there is a large amount of red fluorescence from tdTomato protein in cardiomyocytes, indicating strong expression of Cre recombinase in this location. In the corresponding tissues of the control group (Cre-) mice, no expression of tdTomato red fluorescence was detected, indicating an absence of Cre recombinase expression.

In Cre+ mice, there is a small amount of red fluorescence from tdTomato protein in the kidneys, lungs, and skeletal muscle, indicating some activity of Cre recombinase in these locations. In the corresponding tissues of the control group (Cre-) mice, no expression of red fluorescence was detected, indicating an absence of Cre recombinase expression.

In Cre+ mice, there is a very small amount of red fluorescence from tdTomato protein in the lamina propria cells of the uterus and mesenchymal cells of the testis, indicating the extremely low expression of Cre recombinase activity. In the corresponding tissues of the control group (Cre-) mice, no expression of tdTomato red fluorescence was detected, indicating an absence of Cre recombinase expression.

In the H11-Myh6-iCre mouse model, the expression of Cre recombinase is mainly located in the cardiomyocytes, with a small amount of Cre recombinase activity also present in some tissues of the kidneys, lungs, and skeletal muscle. In addition, a very small amount of Cre recombinase expression was detected in the uterus and testis. In summary, the expression pattern of Cre recombinase in this model is roughly similar to that of the endogenous Myh6 gene in mice and the model can be used as a cardiomyocyte-specific Cre mice.