hCLE/C14orf166 Associates with DDX1-HSPC117-FAM98B in a Novel Transcription-Dependent Shuttling RNA-Transporting Complex

• DOI: 10.1371/journal.pone.0090957
• Publication Date: 2014-03-07T16:28:11Z
• Authors: Alicia Pérez-Gonz...; Alejandra Pazo; Rosana Navajas; Sergio Ciordia; Ariel Rodriguez-F...; Amelia Nieto
• Keywords: 0301 basic medicine; Cytoplasm; Transcription, Genetic; Science; Genetic Vectors; Active Transport, Cell Nucleus; DEAD-box RNA Helicases; 03 medical and health sciences; Humans; RNA, Messenger; Cell Nucleus; 0303 health sciences; Q; Lentivirus; R; Proteins; Molecular Sequence Annotation; HEK293 Cells; Gene Expression Regulation; Trans-Activators; Medicine; Protein Multimerization; Carrier Proteins; Research Article; Protein Binding; Signal Transduction

hCLE/C14orf166 is a nuclear and cytoplasmic protein that interacts with the RNAP II, modulates nuclear RNA metabolism and is present in cytoplasmic RNA granules involved in localized translation. Here we have studied whether hCLE shares common interactors in the nucleus and the cytosol, which could shed light on its participation in the sequential phases of RNA metabolism. Nuclear and cytoplasmic purified hCLE-associated factors were identified and proteins involved in mRNA metabolism, motor-related proteins, cytoskeletal and translation-related factors were found. Purified hCLE complexes also contain RNAs and as expected some hCLE-interacting proteins (DDX1, HSPC117, FAM98B) were found both in the nucleus and the cytoplasm. Moreover, endogenous hCLE fractionates in protein complexes together with DDX1, HSPC117 and FAM98B and silencing of hCLE down-regulates their nuclear and cytosolic accumulation levels. Using a photoactivatable hCLE-GFP protein, nuclear import and export of hCLE was observed indicating that hCLE is a shuttling protein. Interestingly, hCLE nuclear import required active transcription, as did the import of DDX1, HSPC117 and FAM98B proteins. The data indicate that hCLE probably as a complex with DDX1, HSPC117 and FAM98B shuttles between the nucleus and the cytoplasm transporting RNAs suggesting that this complex has a prominent role on nuclear and cytoplasmic RNA fate.