Zebrafish HSC70 promoter to express carp muscle-specific creatine kinase for acclimation under cold condition.

Zebrafish (Danio rerio) is used as a model system for in vivo studies. To expand the research scope of physical, biochemical and physiological studies, a cold-tolerant model of zebrafish was developed. The common carp (Cyprinus carpio) muscle form of creatine kinase (CK, EC 2.7.3.2) can maintain enzymatic activity at a temperature of around 15°C. However, a cold-inducible promoter of zebrafish, hsc 70 (heat shock protein 70 cognate), is able to increase the expression of gene product by 9.8 fold at a temperature of 16°C. Therefore, the carp CK gene was promoted by hsc 70 and transfected into zebrafish embryos. Resulting transgenic zebrafish survived and could maintain its swimming behavior at 13°C, which was not possible with the wild-type zebrafish. The swimming distance of the transgenic fish was 42% greater than that of the wild type at 13°C. This new transgenic fish model is ideal for studies of ectothermal vertebrates in low-temperature environments.