The dynamics of secretion during sea urchin embryonic skeleton formation.
The dynamics of secretion during sea urchin embryonic skeleton formation.
复制标题
海胆胚胎骨骼形成过程中的分泌动态。
DOI：
10.1016/j.yexcr.2008.01.036
复制
发表时间：
2008
影响因子：
3.7
通讯作者：
Croker,Lindsay
中科院分区：
文献类型：
--
作者：
Wilt,FredH;Killian,ChristopherE;Hamilton,Patricia;Croker,Lindsay
骨骼的形成涉及大量矿物质前体（通常是钙盐）和基质蛋白质的分泌，其中许多沉积在矿物质上，甚至被矿物质堵塞。这种分泌和随后的生物矿化骨骼元素组装的细胞生物学基础尚不清楚。我们在这里要问的是，在海胆胚胎的初级间充质细胞（沉积内骨骼针尖的细胞）中，矿物质和基质的运输和分泌是什么关系。细胞内钙沉积的荧光标记显示，在光镜下可见的颗粒中存在矿物前体，它们从那里沉积在内骨骼针状体中，特别是在针状体的尖端。相比之下，两种不同的标记有绿色荧光蛋白的基质蛋白存在于更小的高尔基后囊泡中，只有在电子显微镜下才能看到，而且分泌的蛋白只被合并到起源细胞附近的针状体中。基质蛋白SpSM30B在分泌过程中被翻译后修饰，这种修饰在进入针状体后继续进行。我们的研究结果还表明，矿物质前体和两种表征良好的基质蛋白通过不同的细胞途径运输。
Skeleton formation involves secretion of massive amounts of mineral precursor, usually a calcium salt, and matrix proteins, many of which are deposited on, or even occluded within, the mineral. The cell biological underpinnings of this secretion and subsequent assembly of the biomineralized skeletal element is not well understood. We ask here what is the relationship of the trafficking and secretion of the mineral and matrix within the primary mesenchyme cells of the sea urchin embryo, cells that deposit the endoskeletal spicule. Fluorescent labeling of intracellular calcium deposits show mineral precursors are present in granules visible by light microscopy, from whence they are deposited in the endoskeletal spicule, especially at its tip. In contrast, two different matrix proteins tagged with GFP are present in smaller post-Golgi vesicles only seen by electron microscopy, and the secreted protein are only incorporated into the spicule in the vicinity of the cell of origin. The matrix protein, SpSM30B, is post-translationally modified during secretion, and this processing continues after its incorporation into the spicule. Our findings also indicate that the mineral precursor and two well characterized matrix proteins are trafficked by different cellular routes.