Malatesta M, Zancanaro C, Tamburini M, Martin T E, Fu X D, Vogel P, Fagan S
Centre of Electron Microscopy, University of Lausanne, 27 Bugnon, CH-1005 Lausanne, Switzerland.
Chromosoma. 1995 Nov;104(2):121-8. doi: 10.1007/BF00347694.
Adrenocortical cell nuclei of the dormouse Muscardinus avellanarius were investigated by electron microscopic immunocytochemistry in hibernating, arousing and euthermic individuals. While the basic structural constituents of the cell nucleus did not significantly modify in the three groups, novel structural components were found in nuclei of hibernating dormice. Lattice-like bodies (LBs), clustered granules (CGs), fibrogranular material (FGM) and granules associated with bundles of nucleoplasmic fibrils (NF) all contained ribonucleoproteins (RNPs), as shown by labeling with anti-snRNP (small nuclear RNP), anti-m3G-capped RNA and anti-hnRNP (heterogeneous nuclear RNP) antibodies. Moreover, the FGM also showed immunoreactivity for the proliferation associated nuclear antigen (PANA) and the non-snRNP splicing factor SC-35. All these nuclear structural components disappeared early during arousal and were not found in euthermic animals. These novel RNP-containing structures, which have not been observed in other tissues investigated so far in the same animal model, could represent storage and/or processing sites for pre-mRNA during the extreme metabolic condition of hibernation, to be quickly released upon arousal. NFs, which had been sometimes found devoid of associated granules in nuclei of brown adipose tissue from hi-bernating dormice, were present in much higher amounts in adrenocortical cell nuclei; they do not contain RNPs and their role remains to be elucidated. The possible roles of these structures are discussed in the frame of current knowledge of morpho-functional relationships in the cell nucleus.
通过电子显微镜免疫细胞化学方法，对榛睡鼠（Muscardinus avellanarius）冬眠、觉醒和常温状态下个体的肾上腺皮质细胞核进行了研究。虽然细胞核的基本结构成分在这三组中没有显著改变，但在冬眠榛睡鼠的细胞核中发现了新的结构成分。晶格样小体（LBs）、聚集颗粒（CGs）、纤维颗粒物质（FGM）以及与核质纤维束（NF）相关的颗粒均含有核糖核蛋白（RNPs），这通过用抗snRNP（小核核糖核蛋白）、抗m3G加帽RNA和抗hnRNP（不均一核核糖核蛋白）抗体标记得以证实。此外，FGM对增殖相关核抗原（PANA）和非snRNP剪接因子SC - 35也显示出免疫反应性。所有这些核结构成分在觉醒早期消失，在常温动物中未发现。这些含有RNP的新结构，在迄今同一动物模型中研究的其他组织中尚未观察到，可能代表了冬眠极端代谢条件下前体mRNA的储存和/或加工位点，在觉醒时迅速释放。NFs在冬眠榛睡鼠棕色脂肪组织细胞核中有时被发现没有相关颗粒，而在肾上腺皮质细胞核中含量要高得多；它们不含RNPs，其作用仍有待阐明。在当前细胞核形态功能关系知识框架内讨论了这些结构的可能作用。
