West Jason A, Mito Mari, Kurosaka Satoshi, Takumi Toru, Tanegashima Chiharu, Chujo Takeshi, Yanaka Kaori, Kingston Robert E, Hirose Tetsuro, Bond Charles, Fox Archa, Nakagawa Shinichi
Department of Molecular Biology, Massachusetts General Hospital, Boston, MA 02114 Department of Genetics, Harvard Medical School, Boston, MA 02115.
RNA Biology Laboratory, RIKEN, Wako 351-0198, Japan.
J Cell Biol. 2016 Sep 26;214(7):817-30. doi: 10.1083/jcb.201601071. Epub 2016 Sep 19.
Paraspeckles are nuclear bodies built on the long noncoding RNA Neat1, which regulates a variety of physiological processes including cancer progression and corpus luteum formation. To obtain further insight into the molecular basis of the function of paraspeckles, we performed fine structural analyses of these nuclear bodies using structural illumination microscopy. Notably, paraspeckle proteins are found within different layers along the radially arranged bundles of Neat1 transcripts, forming a characteristic core-shell spheroidal structure. In cells lacking the RNA binding protein Fus, paraspeckle spheroids are disassembled into smaller particles containing Neat1, which are diffusely distributed in the nucleoplasm. Sequencing analysis of RNAs purified from paraspeckles revealed that AG-rich transcripts associate with Neat1, which are distributed along the shell of the paraspeckle spheroids. We propose that paraspeckles sequester core components inside the spheroids, whereas the outer surface associates with other components in the nucleoplasm to fulfill their function.
旁斑是基于长链非编码RNA Neat1构建的核体，其调节包括癌症进展和黄体形成在内的多种生理过程。为了进一步深入了解旁斑功能的分子基础，我们使用结构照明显微镜对这些核体进行了精细结构分析。值得注意的是，旁斑蛋白存在于沿Neat1转录本径向排列的束状结构的不同层中，形成特征性的核壳球状结构。在缺乏RNA结合蛋白Fus的细胞中，旁斑球体被分解成含有Neat1的较小颗粒，这些颗粒分散分布在核质中。对从旁斑中纯化的RNA进行测序分析表明，富含AG的转录本与Neat1相关联，它们沿着旁斑球体的外壳分布。我们提出，旁斑将核心成分隔离在球体内，而其外表面与核质中的其他成分结合以发挥其功能。
