Johnson Robert P, Kang Seong Hoon, Kramer James M
Department of Cell and Molecular Biology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA.
Development. 2006 May;133(10):1911-21. doi: 10.1242/dev.02363. Epub 2006 Apr 12.
The C. elegans dystroglycan (DG) homolog DGN-1 is expressed in epithelia and neurons, and localizes to basement membrane (BM) surfaces. Unlike vertebrate DG, DGN-1 is not expressed in muscle or required for muscle function. dgn-1 null mutants are viable but sterile owing to severe disorganization of the somatic gonad epithelium, and show defects in vulval and excretory cell epithelia and in motoneuron axon guidance. The defects resemble those of epi-1 laminin alphaB mutants, suggesting that DGN-1 serves as a receptor for laminin. dgn-1(0)/+ animals are fertile but show gonad migration defects in addition to the defects seen in homozygotes, indicating that DGN-1 function is dosage sensitive. Phenotypic analyses show that DGN-1 and dystrophin-associated protein complex (DAPC) components have distinct and independent functions, in contrast to the situation in vertebrate muscle. The DAPC-independent functions of DGN-1 in epithelia and neurons suggest that vertebrate DG may also act independently of dystrophin/utrophin in non-muscle tissues.
秀丽隐杆线虫的营养不良聚糖（DG）同源物DGN-1在上皮细胞和神经元中表达，并定位于基底膜（BM）表面。与脊椎动物的DG不同，DGN-1在肌肉中不表达，也不是肌肉功能所必需的。dgn-1基因敲除突变体是存活的，但由于体细胞性腺上皮的严重紊乱而不育，并在外阴和排泄细胞上皮以及运动神经元轴突导向方面表现出缺陷。这些缺陷与epi-1层粘连蛋白αB突变体的缺陷相似，表明DGN-1作为层粘连蛋白的受体。dgn-1(0)/+动物是可育的，但除了纯合子中出现的缺陷外，还表现出性腺迁移缺陷，这表明DGN-1的功能对剂量敏感。表型分析表明，与脊椎动物肌肉中的情况相反，DGN-1和肌营养不良蛋白相关蛋白复合体（DAPC）的成分具有不同且独立的功能。DGN-1在上皮细胞和神经元中不依赖DAPC的功能表明，脊椎动物的DG在非肌肉组织中也可能独立于肌营养不良蛋白/抗肌萎缩蛋白发挥作用。
