Medusoid fibril bodies: a novel type of nuclear filament of diameter 8 to 12 nm with periodic ultrastructure demonstrated in oocytes of Xenopus laevis.
Medusoid fibril bodies: a novel type of nuclear filament of diameter 8 to 12 nm with periodic ultrastructure demonstrated in oocytes of Xenopus laevis.
复制标题
水母原纤维体：一种直径为 8 至 12 nm 的新型核丝，在非洲爪蟾卵母细胞中表现出周期性超微结构。
DOI：
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发表时间：
1982
影响因子：
6.6
通讯作者：
U. Scheer
中科院分区：
文献类型：
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作者：
S. Moreno Díaz de la Espina;W. Franke;G. Krohne;M. Trendelenburg;C. Grund;U. Scheer
非洲爪蟾卵母细胞的核包含许多（几千）直径范围从0.2到1.0 μ m的机构，其中包括一个典型的丝状结构突出的中央致密的聚集体（“水母原纤维体”）。这些核体的超微结构已通过电子显微镜研究，使用切片和扩散制备的核内容物可视化与负和正染色技术。如这些铺展制备物中所示，从密集染色的芯材料延伸的单个细丝相对较长（追踪的最大轮廓长度为2.4 μ m），并且显示出8至12 nm的总直径。在更高的放大倍数下，这些细丝显示出周期性的组织，并且表现为具有约12 nm的平均中心到中心距离的串上珠。偶尔，可以看到其中直径为3至5 nm的芯线细丝被分辨的区域，并且直径约为10 nm的游离球状颗粒位于样品网格上的附近，这表明天然8至12 nm细丝的珠状外观反映了球状10 nm颗粒与3至5 nm芯线细丝的紧密结合。丝状体对胰腺核糖核酸酶、DNA酶1和微球菌核酸酶的处理有抗性，但被蛋白水解酶消化。值得注意的是，3至5nm的芯丝也耐受用高盐缓冲液（2M KCl）处理。这些8至12 nm的珠状蛋白质细丝以可变的频率附着有直径为18至30 nm的大球状颗粒，这些颗粒在形态上类似于分离的前核糖体颗粒。这些水母原纤维体经常出现在核仁的周围，在扩散的制备中经常在核仁基因附近看到，但也出现在核质的其他地方。在其他两栖动物的00细胞和其他各种细胞类型中也发现了具有这种特征性珠状细丝类型的球体。丝水母原纤维体的特点，最近描述的核骨架元素与分离的核仁和它们可能的作用，在提供结构支持preribosomal颗粒的可能关系进行了讨论。
Nuclei of oocytes of Xenopus laevis contain numerous (several thousand) bodies of diameters ranging from 0.2 to 1.0 Ilm which are composed of a characteristic type of filamentous structures projecting from a central dense aggregate ("medusoid fibrillar bodies"). The ultrastructure of these nuclear bodies has been studied by electron microscopy using ultrathin sections and spread preparations of nuclear contents visualized with negative and positive staining techniques. As shown in these spread preparations, the individual filaments which extend from the densely stained core material are relatively long (maximal contour length traced 2.4 ~m) and show an overall diameter of 8 to 12 nm. At higher magnification these filaments reveal a periodic organization and appear as beads-on-a-string with an average center-to-center distance of approximately 12 nm. Occasionally, regions are seen in which a core thread filament of diameter 3 to 5 nm is resolved and free spheroidal particles of about 10 nm diameter lie nearby on the specimen grid, suggesting that the beaded aspect of the native 8 to 12 nm filaments reflects the close association of spheroidal 10 nm particles with the 3 to 5 nm core thread filament. The filaments are resistant to treatments with pancreatic ribonuclease, DNAse 1 and micrococcal nuclease but are digested with proteolytic enzymes. Notably the 3 to 5 nm core filament are also resistant to treatment with high salt buffers (2 M KCI). To these 8 to 12 nm beaded protein filaments are attached, at variable frequencies, large spheroidal particles of 18 to 30 nm diameter which morphologically resemble isolated preribosomal particles. These medusoid fibril bodies are frequent in the periphery of nucleoli, and in spread preparations are often seen in close proximity to nucleolar genes, but occur also elsewhere in the nucleoplasm. Spheroidal bodies with this characteristic type of beaded filaments have also been found in 00cytes of other amphibia and in various other cell types. The possible relationship of the filaments characteristic of the medusoid fibril bodies to the karyoskeletal elements recently described in association with isolated nucleoli and their possible role in providing structural support to preribosomal particles is discussed.