Establishment of cardiac-specific Cre recombinase transgenic mice

Objective: To obtain a mouse that specifically expresses Cre recombinase in cardiomyocyte. Methods:A construct that directed the expression of Cre recombinase to cardiomyocytes was made. The linearized constructs were introduced into the fertilized eggs by microinjection to obtain the transgenic mice. The integration of Cre recombinase gene was detected using PCR. The tissue-specific expression of the Cre recombinase was confirmed by Northern blot. Results:A cardiomyocyte-specific Cre transgenic construct containing the α-myosin heavy chain (α-MHC) promoter, Cre recombinase gene and polyA of human growth hormone gene was generated. The linearized constructs were introduced into 215 fertilized zygotes by microinjection. Two hundred and two injected eggs were implanted into the oviduct of 13 female mice. Forty two offspring were obtained. One mouse carrying the Cre recombinase gene was identified by PCR. The results of Northern blot examination of multiple tissues showed that the Cre recombinase was expressed only in the cardiac tissue. Conclusion: A cardiomyocyte-specific Cre recombinase transgenic mouse was generated successfully. It could serve as a useful tool for studying gene function in heart development and related diseases using conditional gene knockout approach.