title: The Sam68 nuclear body is composed of two RNase-sensitive substructures joined by the adaptor HNRNPL.
abstract: The mammalian cell nucleus contains membraneless suborganelles referred to as nuclear bodies (NBs). Some NBs are formed with an architectural RNA (arcRNA) as the structural core. Here, we searched for new NBs that are built on unidentified arcRNAs by screening for ribonuclease (RNase)-sensitive NBs using 32,651 fluorescently tagged human cDNA clones. We identified 32 tagged proteins that required RNA for their localization in distinct nuclear foci. Among them, seven RNA-binding proteins commonly localized in the Sam68 nuclear body (SNB), which was disrupted by RNase treatment. Knockdown of each SNB protein revealed that SNBs are composed of two distinct RNase-sensitive substructures. One substructure is present as a distinct NB, termed the DBC1 body, in certain conditions, and the more dynamic substructure including Sam68 joins to form the intact SNB. HNRNPL acts as the adaptor to combine the two substructures and form the intact SNB through the interaction of two sets of RNA recognition motifs with the putative arcRNAs in the respective substructures.
authors.affiliation: Institute for Genetic Medicine, Hokkaido University, Sapporo 060-0815, Japan.
authors.forename: Taro
authors.identifier: 0000-0002-7227-8509
authors.initials: T
authors.lastname: Mannen
authors.affiliation: Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa 277-8562, Japan.
authors.forename: Seisuke
authors.initials: S
authors.lastname: Yamashita
authors.affiliation: Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa 277-8562, Japan.
authors.forename: Kozo
authors.identifier: 0000-0002-7374-3898
authors.initials: K
authors.lastname: Tomita
authors.affiliation: Molecular Profiling Research Center for Drug Discovery, National Institute of Advanced Industrial Science and Technology, Koutou 135-0064, Japan.
authors.forename: Naoki
authors.initials: N
authors.lastname: Goshima
authors.affiliation: Institute for Genetic Medicine, Hokkaido University, Sapporo 060-0815, Japan hirose@igm.hokudai.ac.jp.
authors.forename: Tetsuro
authors.identifier: 0000-0003-1068-5464
authors.initials: T
authors.lastname: Hirose
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000737:chemistry* / Q000378:metabolism*; D000595:Amino Acid Sequence; D000818:Animals; D045744:Cell Line, Tumor; D004268:DNA-Binding Proteins / Q000737:chemistry* / Q000378:metabolism*; D006801:Humans; D045586:Intranuclear Inclusion Bodies / Q000378:metabolism*; D051379:Mice; D008954:Models, Biological; D041681:NIH 3T3 Cells; D000072417:Protein Domains; D000071377:RNA Recognition Motif; D016601:RNA-Binding Proteins / Q000737:chemistry* / Q000378:metabolism*; D012260:Ribonucleases / Q000378:metabolism*; D012261:Ribonucleoproteins / Q000378:metabolism*; D034664:Heterogeneous-Nuclear Ribonucleoprotein L
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D004268:DNA-Binding Proteins; D016601:RNA-Binding Proteins; D012260:Ribonucleases; D012261:Ribonucleoproteins; C527450:CCAR2 protein, human; C400563:HNRNPL protein, human; D034664:Heterogeneous-Nuclear Ribonucleoprotein L; C489559:KHDRBS1 protein, human