Discrete nuclear domains of poly(A) RNA and their relationship to the functional organization of the nucleus.
Discrete nuclear domains of poly(A) RNA and their relationship to the functional organization of the nucleus.
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poly（a）RNA的离散核域及其与核的功能组织的关系。
DOI：
10.1083/jcb.115.5.1191
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发表时间：
1991-12
影响因子：
7.8
通讯作者：
Lawrence, J B
中科院分区：
文献类型：
--
作者：
Carter, K C;Taneja, K L;Lawrence, J B
使用荧光显微镜方法研究了细胞核的功能组织，这种方法允许整合RNA、DNA和蛋白质的位置信息。在从海胆到人类的细胞中，核多聚(A)RNA被发现主要集中在几个离散的“转录域”中，这些转录域通常围绕着核仁。Poly(A)RNA的浓度与SnRNP抗原簇的浓度一致，为前mRNA剪接在这些位点的定位提供了证据。建立了转录结构域与各类DNA的空间关系，即Poly(A)RNA富集区与DNA密度低的离散区域重合，并相对于特定的DNA序列非随机分布。着丝粒DNA和晚期复制DNA不会重叠转录域，而早期复制DNA的子集可能会重叠。结果表明，转录域并不是与中期染色体带相对应的染色质的简单聚集直接产生的。最后，对有丝分裂后这些结构域的重组的观察表明，SnRNP抗原的聚集可能依赖于PolII转录的重新出现。这些发现对整个核结构和功能的影响被考虑，包括关于转录域是否可能是反映活性基因聚集的聚合酶II转录的位置的讨论。
The functional organization of the nucleus was studied using a fluorescence microscopy approach which allowed integration of positional information for RNA, DNA, and proteins. In cells from sea urchin to human, nuclear poly(A) RNA was found concentrated primarily within several discrete "transcript domains" which often surrounded nucleoli. Concentrations of poly(A) RNA were coincident with snRNP antigen clusters, providing evidence for the localization of pre-mRNA splicing at these sites. The spatial relationship of transcript domains with respect to various classes of DNA was established, in that the poly(A) RNA-rich regions coincided with discrete regions of low DNA density and were non-randomly distributed with respect to specific DNA sequences. Centromeric DNA and late-replicating DNA did not overlap transcript domains, whereas a subset of early-replicating DNA may. Results indicate that transcript domains do not result directly from a simple clustering of chromatin corresponding to metaphase chromosomes bands. Finally, observations on the reassembly of these domains after mitosis suggest that the clustering of snRNP antigens may be dependent on the reappearance of pol II transcription. Implications of these findings for overall nuclear structure and function are considered, including a discussion of whether transcript domains may be sites of polymerase II transcription reflecting a clustering of active genes.