Generation of transgenic mice with arrythmia expressing a dominant-negative Isk

To understand physiological function of the Isk channel in heart，investigated behavior of the Isk channels in three different ways；in mammalian cultured cells，in isolated ventricular myocytes and in the heart of transgenic mice.(1) in COS7 cells transfected，Isk was associated with KvLQT1 and HERG. The rapidly activating potassium current was abolished bycotransfection of D77N dominant negative Isk and HERG cDNA.(2)In isolated ventricular myocytes，two types of outward K - D2+ d - 2 currents，the rapidly activating potassium channel (which corresponds to IKr) and the slowly activatingpotassium channels （which corresponds to IKs）are identified. The outward K - D2+ d - 2 currents were inhibited by The antisense Isk oligonucleotideor D77N dominant negative Isk mutant. The action potential duration in ventricular myocyte was(3)Transgenic mice significantly prolonged by introduction of D77N dominant negative mutant.(3)Transgenic miceexpressing a dominant-negative D77N Isk in heart were generated under the control of α-myosin heavychain promoter. The introduced Isk was strongly expressed in The heart. The electrocardiogram of Themice and electrophysiology using the isolated ventricular myocytes from the mice have beenanalyzed。

To understand physiological function of the Isk channel in heart, we investigated behavior of the Isk channels in three different ways ; in mammalian cultured cells, in isolated ventricular myocytes and in the heart of transgenic mice.(1)In COS7 cells transfected, Isk was associated with KvLQT1 and HERG. The rapidly activating potassium current was abolished by cotransfection of D77N dominant negative Isk and HERG cDNA.(2)In isolated ventricular myocytes, two types of outward KィイD2+ィエD2 currents, the rapidly activating potassium channel (which corresponds to IKr) and the slowly activating potassium channels (which corresponds to IKs), are identified. The outward KィイD2+ィエD2 currents were inhibited by the antisense Isk oligonucleotide or D77N dominant negative Isk mutant. The action potential duration in ventricular myocyte was significantly prolonged by introduction of D77N dominant negative mutant.(3)Transgenic mice expressing a dominant-negative D77N Isk in heart were generated under the control of α-myosin heavy chain promoter. The introduced Isk was strongly expressed in the heart. The electrocardiogram of the mice and electrophysiology using the isolated ventricular myocytes from the mice have been analyzed.