Conditional Antisense-Knockdown of Zebrafish Cardiac Troponin C as a New Animal Model for Dilated Cardiomyopathy

Abstract

Mutations of cardiac troponin C (cTnC) can cause dilated cardiomyopathy in humans. Plasmids were constructed such that the reverse tetracycline-controlled transactivator (rtTA) was driven by the cardiac myosin light chain 2 promoter. This heart-specific rtTA bound another bidirectional promoter to express the green fluorescence protein reporter gene and the antisense RNA of cTnC in the presence of doxycycline. A transgenic line of zebrafish (CA17) with cTnC dysfunction was also generated. The heart rates of the embryos in the CA17 line were significantly slower than those of embryos in the control T03 transgenic line at 6 and 12 days post fertilization (dpf). In the CA17 line, cardiac chambers in the F2 embryos were significantly greater and the ventricular ejection fraction was lower than those in the T03 at both 6 and 12 dpf. The mortality rate of F2 adult fish of the CA17 line was also significantly higher (P<0.001). Using conditional expression of antisense RNA of zebrafish cTnC, a new animal model with phenotypes simulating dilated cardiomyopathy has been created.