Ojamaa K, Klein I
Department of Medicine, North Shore University Hospital/Cornell University Medical College, Manhasset, New York 11030.
Biochem Biophys Res Commun. 1991 Sep 30;179(3):1269-75. doi: 10.1016/0006-291x(91)91710-t.
We have studied the thyroid-hormone responsiveness of the alpha-myosin heavy chain (MHC) gene in vivo by directly injecting an expression vector containing the alpha-MHC 5' regulatory sequences (-613 to +421 base pairs) into the rat heart. In the expression vector pAM1Luc the alpha-MHC promoter elements direct the synthesis of firefly luciferase. Although thyroxine administration of both euthyroid and thyroidectomized rats for 5 days increased alpha-MHC promoter activity, the pAM1Luc gene construct did not mimic expression of the endogenous gene. These studies of direct gene transfer into mammalian myocardium suggest that additional cis-acting elements necessary for the in vivo response to thyroid hormone reside outside the -613 to +421 region.
我们通过将包含α-肌球蛋白重链（MHC）5'调控序列（-613至+421碱基对）的表达载体直接注射到大鼠心脏中，在体内研究了α-肌球蛋白重链基因对甲状腺激素的反应性。在表达载体pAM1Luc中，α-MHC启动子元件指导萤火虫荧光素酶的合成。尽管对正常甲状腺和甲状腺切除的大鼠给予甲状腺素5天可增加α-MHC启动子活性，但pAM1Luc基因构建体并未模拟内源性基因的表达。这些将基因直接转移到哺乳动物心肌中的研究表明，体内对甲状腺激素反应所必需的其他顺式作用元件位于-613至+421区域之外。
