LOCALIZATION OF BONE SIALOPROTEIN (BSP) TO GOLGI AND POST-GOLGI SECRETORY STRUCTURES IN OSTEOBLASTS AND TO DISCRETE SITES IN EARLY BONE-MATRIX
LOCALIZATION OF BONE SIALOPROTEIN (BSP) TO GOLGI AND POST-GOLGI SECRETORY STRUCTURES IN OSTEOBLASTS AND TO DISCRETE SITES IN EARLY BONE-MATRIX
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DOI：
10.1177/41.2.8419459
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发表时间：
1993-02-01
影响因子：
3.2
通讯作者：
ROBEY, PG
中科院分区：
文献类型：
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作者：
BIANCO, P;RIMINUCCI, M;ROBEY, PG
骨唾液酸蛋白(BSP)是一种含有Arg-Gly-Asp(RGD)基序的富含骨基质的糖蛋白，具有细胞结合特性，在超微结构水平上定位于成骨细胞和发育早期的骨基质中。初步的光镜观察表明，细胞内标记仅限于核旁的一个点，与经典组织学中的“负高尔基像”相对应。无论是使用针对完全糖化蛋白的抗血清还是针对人BSP序列中一段氨基酸的多肽抗血清，都观察到了相同的模式。在EM水平，我们获得了成骨细胞高尔基体区域的标记，但不是在RER上。标记集中在反高尔基体扩张和分泌前颗粒上。在基质中，BSP以非随机的方式分布。标签集中在与早期矿物沉积位置(所谓的“矿化结节”)相对应的细小纤维状材料的球形聚集体上。这样的BSP阳性灶在靠近和远离细胞表面都可见。BSP与高尔基体和高尔基体后分泌结构的主要联系以及它在RER中的缺失，以及不同抗血清对相同定位模式的重复性，可能表明蛋白质通过高尔基体的缓慢运输，而不一定与蛋白质糖基化有关。
Bone sialoprotein (BSP), a bone matrix-enriched glycoprotein containing the Arg-Gly-Asp (RGD) motif and endowed with cell binding properties, was localized in osteoblasts and early bone matrix of developing rat bone at the ultrastructural level. Preliminary light microscopic observations indicated that intracellular labelling was restricted to a paranuclear dot corresponding to the ''negative Golgi image'' of classical histology. The same pattern was observed whether antisera against the fully glycosylated protein or a peptide antiserum to a stretch of amino acids in human BSP sequence were employed. At the EM level, we obtained labeling over the Golgi area of osteoblasts but not over the rER. The labeling was concentrated over distensions of the trans Golgi and over pro-secretory granules. In the matrix, BSP was distributed in a non-random manner. The label was concentrated over spherical aggregates of finely fibrillar material corresponding to the sites of early mineral deposition (so-called ''mineralization nodules''). Such BSP-positive foci were seen both close to and away from the cell surface. The predominant association of BSP with Golgi and post-Golgi secretory structures and its absence from rER, as well as the reproducibility of the same pattern of localization with different antisera, might indicate a slow transit of the protein through the Golgi, not necessarily associated with protein glycosylation.