Ziak M, Qu B, Zuo X, Zuber C, Kanamori A, Kitajima K, Inoue S, Inoue Y, Roth J
Department of Pathology, University of Zurich, Switzerland.
Proc Natl Acad Sci U S A. 1996 Apr 2;93(7):2759-63. doi: 10.1073/pnas.93.7.2759.
In tissues of higher organisms homopolymers of alpha2,8-linked N-acetylneuraminic acid can be found as a posttranslational modification on selected proteins. We report here the discovery of homopolymers of alpha2,8-linked deaminoneuraminic acid [poly(alpha2,8-KDN)] in various tissues derived from all three germ layers in vertebrates including mammals. The monoclonal antibody kdn8kdn in conjunction with a bacterial KDNase permitted the detection of poly(alpha2,8-KDN) by immunohistochemistry and immunoblotting. Further evidence for the existence of poly(alpha2,8-KDN) was obtained by gas/liquid chromatography. The poly(alpha2,8-KDN) glycan was detectable in all tissues studied with the exception of mucus-producing cells present in various organs, the extracellular matrix, and basement membranes. However, in certain organs such as muscle, kidney, lung, and brain its expression was developmentally regulated. Despite its widespread tissue distribution, the poly(alpha2,8-KDN) glycan was detected on a single 150-kDa glycoprotein except for a single >350-kDa glycoprotein in kidney, which makes it most distinctive among polysialic acids. The ubiquitous yet selective expression may be indicative of a general function of the poly(alpha2,8-KDN)-bearing glycoproteins.
在高等生物的组织中，α2,8-连接的N-乙酰神经氨酸同聚物可作为特定蛋白质的翻译后修饰被发现。我们在此报告，在包括哺乳动物在内的脊椎动物的所有三个胚层来源的各种组织中发现了α2,8-连接的脱氨神经氨酸同聚物[聚（α2,8-KDN）]。单克隆抗体kdn8kdn与细菌KDNase结合，可通过免疫组织化学和免疫印迹检测聚（α2,8-KDN）。通过气相/液相色谱法获得了聚（α2,8-KDN）存在的进一步证据。除了存在于各种器官、细胞外基质和基底膜中的黏液分泌细胞外，在所研究的所有组织中均可检测到聚（α2,8-KDN）聚糖。然而，在某些器官如肌肉、肾脏、肺和脑中，其表达受发育调控。尽管聚（α2,8-KDN）聚糖在组织中广泛分布，但除了肾脏中的一种大于350 kDa的糖蛋白外，它只在一种150 kDa的糖蛋白上被检测到，这使其在多唾液酸中最为独特。这种普遍存在但具有选择性的表达可能表明携带聚（α2,8-KDN）的糖蛋白具有一般功能。
