MENε/β noncoding RNAs are essential for structural integrity of nuclear paraspeckles

Recent transcriptome analyses have shown that thousands of noncoding RNAs (ncRNAs) are transcribed from mammalian genomes. Although the number of functionally annotated ncRNAs is still limited, they are known to be frequently retained in the nucleus, where they coordinate regulatory networks of gene...

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Bibliographic Details
Published in:Proceedings of the National Academy of Sciences - PNAS 2009-02, Vol.106 (8), p.2525-2530
Main Authors: Sasaki, Yasnory T.F, Ideue, Takashi, Sano, Miho, Mituyama, Toutai, Hirose, Tetsuro
Format: Article
Language:English
Subjects:
3T3 cells
Actinomycin
Antibodies
Biological Sciences
Cell lines
Genetic loci
HeLa cells
Nuclear structure
Protein isoforms
RNA
T lymphocytes
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Summary:Recent transcriptome analyses have shown that thousands of noncoding RNAs (ncRNAs) are transcribed from mammalian genomes. Although the number of functionally annotated ncRNAs is still limited, they are known to be frequently retained in the nucleus, where they coordinate regulatory networks of gene expression. Some subnuclear organelles or nuclear bodies include RNA species whose identity and structural roles are largely unknown. We identified 2 abundant overlapping ncRNAs, MENε and MENβ (MENε/β), which are transcribed from the corresponding site in the multiple endocrine neoplasia (MEN) I locus and which localize to nuclear paraspeckles. This finding raises the intriguing possibility that MENε/β are involved in paraspeckle organization, because paraspeckles are, reportedly, RNase-sensitive structures. Successful removal of MENε/β by a refined knockdown method resulted in paraspeckle disintegration. Furthermore, the reassembly of paraspeckles disassembled by transcriptional arrest appeared to be unsuccessful in the absence of MENε/β. RNA interference and immunoprecipitation further revealed that the paraspeckle proteins p54/nrb and PSF selectively associate with and stabilize the longer MENβ, thereby contributing to the organization of the paraspeckle structure. The paraspeckle protein PSP1 is not directly involved in either MENε/β stabilization or paraspeckle organization. We postulate a model for nuclear paraspeckle body organization where specific ncRNAs and RNA-binding proteins cooperate to maintain and, presumably, establish the structure.
ISSN:0027-8424
1091-6490
DOI:10.1073/pnas.0807899106