Hypophosphorylated SR splicing factors transiently localize around active nucleolar organizing regions in telophase daughter nuclei
Hypophosphorylated SR splicing factors transiently localize around active nucleolar organizing regions in telophase daughter nuclei
复制标题
DOI：
10.1083/jcb.200404120
复制
发表时间：
2004-10-11
影响因子：
7.8
通讯作者：
Spector, DL
中科院分区：
文献类型：
--
作者：
Bubulya, PA;Prasanth, KV;Spector, DL
有丝分裂完成后，子核组装所有必要的细胞器，以实现核功能。我们发现，在进入子细胞核，snRNP和SIR蛋白不立即共定位在核斑点。SIR蛋白聚集在活跃的核仁组织区（NOR）周围的斑块中，我们称之为NOR。相关补丁（NAP），而snRNP富集在其他核区域。NAP短暂形成，持续15-20分钟，然后随着G1中开始形成核斑点而消散。在没有RNA聚合酶11转录的情况下，NAP的大小增加，并持续至少2小时，延迟SR蛋白定位到核斑点。另外，NAP中的SR蛋白是低磷酸化的，并且SR蛋白激酶Clk/STY与NAP中的SIR蛋白共定位，这表明磷酸化从NAP释放SIR蛋白，并且它们的初始靶点是转录位点。这项工作证明了以前未被认识到的作用，NAPs在剪接因子贩运和核斑点生物发生。
Upon completion of mitosis, daughter nuclei assemble all of the organelles necessary, for the implementation of nuclear functions. We found that upon entry into daughter nuclei, snRNPs and SIR proteins do not immediately colocalize in nuclear speckles. SIR proteins accumulated in patches around active nucleolar organizing regions (NORs) that we refer to as NOR.-associated patches (NAPs), whereas snRNPs were enriched at other nuclear regions. NAPs formed transiently, persisting for 15-20 min before dissipating as nuclear speckles began to form in G1. In the absence of RNA polymerase 11 transcription, NAPs increased in size and persisted for at least 2 h, with delayed localization of SR proteins to nuclear speckles. In addition, SR proteins in NAPs are hypophosphorylated, and the SR protein kinase Clk/STY colocalizes with SIR proteins in NAPs, suggesting that phosphorylation releases SIR proteins from NAPs and their initial target is transcription sites. This work demonstrates a previously unrecognized role of NAPs in splicing factor trafficking and nuclear speckle biogenesis.