Intranuclear distribution and local dynamics of RNA polymerase II during transcription activation
Intranuclear distribution and local dynamics of RNA polymerase II during transcription activation
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DOI：
10.1016/j.molcel.2007.10.017
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发表时间：
2007-12-28
期刊：
影响因子：
16
通讯作者：
Lis, John T.
中科院分区：
文献类型：
--
作者：
Yao, Jie;Ardehali, M. Behfar;Lis, John T.
转录激活会导致基因的紧凑性和大分子关联性发生戏剧性的变化，在某些情况下，还会触发基因移位到核子结构。在这里，我们用双光子显微镜和FISH技术研究了果蝇热休克(HS)基因在活多线核和二倍体核中的定位、移动和转录动态。不同的HS基因座占据不同的核位置。虽然这些基因座在HS上解聚，但它们不经历可检测到的净易位，也不优先定位于核外围或核内部。此外，光漂白后的荧光恢复显示，在HS后不久，新招募的RNA聚合酶II(POL II)通过一种“有效进入”模式进入伸长，随后在Hsp70位点处逐渐建立转录“隔间”，其中浓缩的POL II以“局部循环”模式使用。在高度转录的发育基因座上，POL II表现出类似于这些Hsp70转录模式的组合的动态。
Transcription activation causes dramatic changes in a gene's compaction and macromolecular associations and, in some cases, triggers the translocation of the gene to a nuclear substructure. Here, we evaluate the location movement, and transcriptional dynamics of Drosophila heat shock (HS) genes both by two-photon microscopy in live polytene nuclei and by FISH in diploid nuclei. The different HS loci occupy separate nuclear positions. Although these loci decondense upon HS, they do not undergo a detectable net translocation nor are they preferentially localized to the nuclear periphery or interior. Additionally, fluorescence recovery after photobleaching reveals that, shortly after HS, newly recruited RNA polymerase II (Pol II) enters elongation via an "efficient entry" mode, which is followed by the progressive establishment of transcription "compartments" at Hsp70 loci where concentrated Pol II is used in a "local recycling" mode. Pol II at highly transcribed developmental loci exhibits dynamics resembling combinations of these Hsp70 transcription modes.