25kD蛋白在人骨骼肌中的定位及在人其他组织中的表达

LOCALIZATION OF 25 kD PROTEIN IN HUMAN SKELETAL MUSCLES AND ITS EXPRESSION IN OTHER HUMAN TISSUES

25 k D蛋白是一种新的与重症肌无力相关的蛋白质。为了检测该蛋白在人体不同组织中的表达并明确其在人骨骼肌中的亚细胞定位。本研究提取和纯化 2 5 k D蛋白 ,免疫小鼠制备了 2 5 k D蛋白的抗体 ;用免疫印迹方法验证了抗体的特异性并检测2 5 k D蛋白在成年人及胎儿 8种不同组织中的表达 ;用免疫组化和免疫电镜方法明确了 2 5 k D蛋白在骨骼肌中的细胞及亚细胞定位。结果显示 ,2 5 k D蛋白抗体只与肌肉匀浆样品中 2 5 k D蛋白特异性反应。在成年人及胎儿 8种不同组织中 ,2 5 k D蛋白只见于骨骼肌。免疫组化可见在肌膜下和横纹上有不均匀的免疫染色 ;免疫电镜显示在肌膜下有电子致密物沉积 ,肌丝中未见有电子致密物沉积。这些结果表明 :2 5 k D蛋白抗体具有很高的特异性 ,2 5 k D蛋白只表达于人骨骼肌中 ,其亚细胞定位在骨骼肌的肌膜下。

25kD protein is a novel protein that is related to myasthenia gravis. In order to detect the expression of 25 kD protein in different human tissues and explore the localization in skeletal muscles, 25 kD protein was extracted and purified. Mice were immunized with 25 kD for 4 times to prepare antibodies. Immuno blot analysises were performed to confirm the specificity of the antibodies and to detect the expression of 25 kD protein in 8 kinds of adult and embryonic human tissues. Immunohistochemistry and immunoelectron microscopy were performed to elucidate the localization of 25 kD protein in human skeletal muscles. The results showed that: The antibodies we prepared reacted specifically with the 25 kD protein band in the muscle extract; among 8 kinds of human tissues including skeletal muscles, smooth muscle, myocardium, thymus, brain, lung, kidney and skin, 25 kD protein was only expressed in skeletal muscles. Immunohistochemistry showed that the 25 kD protein was located asymmetrically at the subserosa of skeletal muscle and on the striations; immunoelectron microscopy ascertained that the localization of the protein was at the subsarcolemma of skeletal muscle but not on the sarcomere and other regions. Our results suggest that 25 kD protein is only express in human skeletal muscles and is localized at the subsarcolemma of skeletal muscles.