P54nrb forms a heterodimer with PSP1 that localizes to paraspeckles in an RNA-dependent manner
P54nrb forms a heterodimer with PSP1 that localizes to paraspeckles in an RNA-dependent manner
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DOI：
10.1091/mbc.e05-06-0587
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发表时间：
2005-11-01
影响因子：
3.3
通讯作者：
Lamond, AI
中科院分区：
文献类型：
--
作者：
Fox, AH;Bond, CS;Lamond, AI
P54nrb是一种参与多种核过程的蛋白质，其特殊功能可能与其存在于不同的核位置有关。在这里，我们描述了paraspeckles，一个包含p54nrb和其他RNA结合蛋白的亚核区域，包括PSP1，一种与p54nrb序列相似的蛋白质，作为paraspeckles的标志。我们发现PSP1在体内与p54nrb总细胞池的一个子集相互作用。我们映射了PSP1中介导这种相互作用的结构域，并证明了它是将PSP1正确定位到paraspeckles所必需的。这种相互作用对于PSP1的副斑点靶向是必要的，但不是充分的，这也需要能够与RNA结合的RRM。在有丝分裂结束时用DRB阻断RNA PolII转录的重新启动，可以防止副斑点的形成，而副斑点的形成在DRB被去除后重新开始，这表明副斑点的形成依赖于RNA聚合酶II的转录。因此，Paraspeckles是p54nrb总细胞池的子集以依赖于RNA聚合酶II的方式被靶向的位置。
P54nrb is a protein implicated in multiple nuclear processes whose specific functions may correlate with its presence at different nuclear locations. Here we characterize paraspeckles, a subnuclear domain containing p54nrb and other RNA-binding proteins including PSP1, a protein with sequence similarity to p54nrb that acts as a marker for paraspeckles. We show that PSP1 interacts in vivo with a subset of the total cellular pool of p54nrb. We map the domain within PSP1 that is mediating this interaction and show it is required for the correct localization of PSP1 to paraspeckles. This interaction is necessary but not sufficient for paraspeckle targeting by PSP1, which also requires an RRM capable of RNA binding. Blocking the reinitiation of RNA PolII transcription at the end of mitosis with DRB prevents paraspeckle formation, which recommences after removal of DRB, indicating that paraspeckle formation is dependent on RNA Polymerase II transcription. Thus paraspeckles are the sites where a subset of the total cellular pool of p54nrb is targeted in a RNA Polymerase II-dependent manner.