Gramolini A O, Wu J, Jasmin B J
Department of Cellular Medicine, Faculty of Medicine, University of Ottawa, Ottawa, Canada K1H 8M5.
Microsc Res Tech. 2000 Apr 1;49(1):90-100. doi: 10.1002/(SICI)1097-0029(20000401)49:1<90::AID-JEMT10>3.0.CO;2-L.
Duchenne muscular dystrophy (DMD) is caused by the absence of full-length dystrophin molecules in skeletal muscle fibers. In normal muscle, dystrophin is found along the length of the sarcolemma where it links the intracellular actin cytoskeleton to the extracellular matrix, via the dystrophin-associated protein (DAP) complex. Several years ago, an autosomal homologue to dystrophin, termed utrophin, was identified and shown to be expressed in a variety of tissues, including skeletal muscle. However, in contrast to the localization of dystrophin in extrajunctional regions of muscle fibers, utrophin preferentially accumulates at the postsynaptic membrane of the neuromuscular junction in both normal and DMD adult muscle fibers. Since it has recently been suggested that the upregulation of utrophin might functionally compensate for the lack of dystrophin in DMD, considerable interest is now directed toward the elucidation of the various regulatory mechanisms presiding over expression of utrophin in normal and dystrophic skeletal muscle fibers. In this review, we discuss some of the most recent data relevant to our understanding of the impact of myogenic differentiation and innervation on the expression and localization of utrophin in skeletal muscle fibers.
杜兴氏肌肉营养不良症（DMD）是由骨骼肌纤维中缺乏全长抗肌萎缩蛋白分子所致。在正常肌肉中，抗肌萎缩蛋白沿肌纤维膜全长分布，通过抗肌萎缩蛋白相关蛋白（DAP）复合物将细胞内肌动蛋白细胞骨架与细胞外基质连接起来。几年前，发现了一种与抗肌萎缩蛋白同源的常染色体蛋白，称为抗肌萎缩蛋白聚糖，它在包括骨骼肌在内的多种组织中表达。然而，与抗肌萎缩蛋白在肌纤维结外区域的定位不同，在正常和DMD成年肌纤维中，抗肌萎缩蛋白聚糖优先聚集在神经肌肉接头的突触后膜上。由于最近有人提出，上调抗肌萎缩蛋白聚糖可能在功能上补偿DMD中抗肌萎缩蛋白的缺乏，因此目前人们对阐明正常和营养不良骨骼肌纤维中抗肌萎缩蛋白聚糖表达的各种调控机制产生了浓厚兴趣。在这篇综述中，我们讨论了一些最新数据，这些数据有助于我们理解肌源性分化和神经支配对骨骼肌纤维中抗肌萎缩蛋白聚糖表达和定位的影响。
