title: Highly ordered spatial organization of the structural long noncoding NEAT1 RNAs within paraspeckle nuclear bodies.
abstract: Paraspeckles (PSPs) are nuclear bodies associated with the retention in the nucleus of specific mRNAs. Two isoforms of a long noncoding RNA (NEAT1_v1/Menε and NEAT1_v2/Menβ) are required for the integrity of PSPs. Here, we analyzed the molecular organization of PSPs by immuno- and in situ hybridization electron microscopy. Detection of the paraspeckle markers PSPC1 and P54NRB/NONO confirm the identity between PSPs and the previously described interchromatin granule-associated zones (IGAZs). High-resolution in situ hybridization of NEAT1 transcripts revealed a highly ordered organization of IGAZ/PSPs. Although the 3.7-kb NEAT1_v1 and the identical 5' end of the 22.7-kb NEAT1_v2 transcripts are confined to the periphery, central sequences of NEAT1_v2 are found within the electron-dense core of the bodies. Moreover, the 3' end of NEAT1_v2 also localize to the periphery, indicating possible architectures for IGAZ/PSPs. These results further suggest that the organization of NEAT1 transcripts constrains the geometry of these bodies. Accordingly, we observed in HeLa and NIH 3T3 cells that IGAZ/PSPs are elongated structures with a well-defined diameter. Our results provide new insight on the ability of noncoding RNAs to form subcellular structures.
authors.affiliation: Centre National de la Recherche Scientifique, Formation de Recherche en Evolution-3238, Institut André Lwoff, Villejuif 94800, France.
authors.forename: Sylvie
authors.initials: S
authors.lastname: Souquere
authors.forename: Guillaume
authors.initials: G
authors.lastname: Beauclair
authors.forename: Francis
authors.initials: F
authors.lastname: Harper
authors.forename: Archa
authors.initials: A
authors.lastname: Fox
authors.forename: Gérard
authors.initials: G
authors.lastname: Pierron
mesh_terms: D000818:Animals; D002460:Cell Line; D002467:Cell Nucleus / Q000378:metabolism* / Q000648:ultrastructure; D006367:HeLa Cells; D006801:Humans; D017403:In Situ Hybridization; D051379:Mice; D008856:Microscopy, Fluorescence; D016253:Microscopy, Immunoelectron; D041681:NIH 3T3 Cells; D009687:Nuclear Proteins / Q000378:metabolism; D012326:RNA Splicing; D022661:RNA, Untranslated / Q000235:genetics*; D016601:RNA-Binding Proteins / Q000378:metabolism
chemical_list: D009687:Nuclear Proteins; C450059:PSPC1 protein, human; D022661:RNA, Untranslated; D016601:RNA-Binding Proteins