RNA Biology Laboratory, RIKEN Advanced Science Institute, 2-1 Hirosawa, Saitama 351-0198, Japan.
J Cell Biol. 2011 Apr 4;193(1):31-9. doi: 10.1083/jcb.201011110. Epub 2011 Mar 28.
Nuclei of higher organisms are well structured and have multiple, distinct nuclear compartments or nuclear bodies. Paraspeckles are recently identified mammal-specific nuclear bodies ubiquitously found in most cells cultured in vitro. To investigate the physiological role of paraspeckles, we examined the in vivo expression patterns of two long noncoding RNAs, NEAT1_1 and NEAT1_2, which are essential for the architectural integrity of nuclear bodies. Unexpectedly, these genes were only strongly expressed in a particular subpopulation of cells in adult mouse tissues, and prominent paraspeckle formation was observed only in the cells highly expressing NEAT1_2. To further investigate the cellular functions of paraspeckles, we created an animal model lacking NEAT1 by gene targeting. These knockout mice were viable and fertile under laboratory growth conditions, showing no apparent phenotypes except for the disappearance of paraspeckles. We propose that paraspeckles are nonessential, subpopulation-specific nuclear bodies formed secondary to particular environmental triggers.
高等生物的细胞核结构良好，具有多个不同的核区室或核体。核斑是最近发现的哺乳动物特异性核体，普遍存在于体外培养的大多数细胞中。为了研究核斑的生理作用，我们研究了两个长非编码 RNA（NEAT1_1 和 NEAT1_2）的体内表达模式，这两个 RNA 对于核体的结构完整性至关重要。出乎意料的是，这些基因仅在成年小鼠组织的特定细胞亚群中强烈表达，并且仅在高度表达 NEAT1_2 的细胞中观察到明显的核斑形成。为了进一步研究核斑的细胞功能，我们通过基因靶向创建了缺乏 NEAT1 的动物模型。这些敲除小鼠在实验室生长条件下具有活力和繁殖力，除了核斑消失外，没有明显的表型。我们提出核斑是非必需的、特定于细胞亚群的核体，是由特定的环境触发因素形成的。
