Transcription-dependent redistribution of the large subunit of RNA polymerase II to discrete nuclear domains.
Transcription-dependent redistribution of the large subunit of RNA polymerase II to discrete nuclear domains.
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DOI：
10.1083/jcb.129.2.287
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发表时间：
1995-04
期刊：
影响因子：
--
通讯作者：
Warren SL
中科院分区：
文献类型：
--
作者：
Bregman DB;Du L;van der Zee S;Warren SL
RNA聚合酶II（Pol II LS）最大亚基的亚群位于20-50个离散的亚核结构域中，这些结构域与存储剪接蛋白的斑点结构域紧密相连。Pol II LS的斑点相关部分在COOH末端结构域（CTD）上高度磷酸化，并且其对洗涤剂提取具有高度抗性。Pol II LS的弥漫性核质部分在CTD上相对低磷酸化，并且易于通过去污剂提取。在转录活性核中，斑点结合的过度磷酸化Pol II LS分子分布在不规则形状的斑点域中，这些斑点域似乎通过网状网络相互连接。当转录被抑制时，过度磷酸化的Pol II LS和剪接蛋白SC 35在斑点结构域中积累，斑点结构域转化为缺乏相互连接的放大的点状结构。当细胞从转录抑制中释放时，Pol IIO和SC 35重新分布回到转录活性细胞的相互连接的斑点图案。Pol II和SC 35的再分布是同步的、可逆的和温度依赖性的。结论是：（a）与其转录活性相比，Pol II LS CTD的过度磷酸化是其与离散的亚核结构域紧密结合的更好的指示剂;（B）在转录抑制状态期间，过度磷酸化的Pol II LS可以储存在放大的斑点结构域中，其在光学显微镜下看起来与剪接蛋白的储存位点一致;和（c）Pol II和剪接蛋白根据细胞核的总体转录活性同时重新分布。
A subpopulation of the largest subunit of RNA polymerase II (Pol II LS) is located in 20-50 discrete subnuclear domains that are closely linked to speckle domains, which store splicing proteins. The speckle- associated fraction of Pol II LS is hyperphosphorylated on the COOH- terminal domain (CTD), and it is highly resistant to extraction by detergents. A diffuse nucleoplasmic fraction of Pol II LS is relatively hypophosphorylated on the CTD, and it is easily extracted by detergents. In transcriptionally active nuclei, speckle bound hyperphosphorylated Pol II LS molecules are distributed in irregularly shaped speckle domains, which appear to be interconnected via a reticular network. When transcription is inhibited, hyperphosphorylated Pol II LS and splicing protein SC35 accumulate in speckle domains, which are transformed into enlarged, dot-like structures lacking interconnections. When cells are released from transcriptional inhibition, Pol IIO and SC35 redistribute back to the interconnected speckle pattern of transcriptionally active cells. The redistribution of Pol II and SC35 is synchronous, reversible, and temperature dependent. It is concluded that: (a) hyperphosphorylation of Pol II LS's CTD is a better indicator of its tight association to discrete subnuclear domains than its transcriptional activity; (b) during states of transcriptional inhibition, hyperphosphorylated Pol II LS can be stored in enlarged speckle domains, which under the light microscope appear to coincide with the storage sites for splicing proteins; and (c) Pol II and splicing proteins redistribute simultaneously according to the overall transcriptional activity of the nucleus.