Goldstein L, Wise G E, Stephenson C, Ko C
J Cell Sci. 1978 Apr;30:227-35. doi: 10.1242/jcs.30.1.227.
For the purpose of studying the relationship of small nuclear RNAs (snRNAs) to chromatin, we studied the effect of the chromatin-binding agent actinomycin D (AMD) on the nuclei of amoebae. By electron microscopy we noted that when mitotic cells were placed in AMD their chromatin was highly condensed 3 h later. This contrasts strikingly with the situation in untreated cells, in which the chromatin at the same time is largely decondensed. After arranging, by nuclear transplantation of labelled nuclei into unlabelled cytoplasm, for the only labelled molecules in the cell to be 3H-snRNAs, we noted that in such cells similarly treated with AMD the labelled material was clustered in a form quite similar to that of the chromatin in 3-h post-division, AMD-treated cells. In untreated cells the 3H-snRNAs were distributed essentially uniformly throughout the nucleus. These observations, together with earlier findings that snRNAs associate with chromosomes during mitosis, lead us to conclude that snRNAs have a particular affinity for condensed chromatin.
为了研究小核RNA（snRNA）与染色质的关系，我们研究了染色质结合剂放线菌素D（AMD）对变形虫细胞核的影响。通过电子显微镜观察，我们发现有丝分裂细胞置于AMD中3小时后，其染色质高度浓缩。这与未处理细胞的情况形成了鲜明对比，在未处理细胞中，此时染色质大部分处于解聚状态。通过将标记的细胞核移植到未标记的细胞质中进行排列，使细胞中唯一的标记分子为3H-snRNA后，我们注意到，在同样用AMD处理的此类细胞中，标记物质聚集的形式与分裂后3小时经AMD处理的细胞中的染色质非常相似。在未处理的细胞中，3H-snRNAs基本上均匀地分布在整个细胞核中。这些观察结果，连同早期发现的snRNAs在有丝分裂期间与染色体相关联，使我们得出结论，snRNAs对浓缩的染色质具有特殊的亲和力。
