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Mun SH, Oh B, Lee MJ, Bae S, Yang Y, Park-Min KH. THOC5 regulates human osteoclastogenesis. Eur J Cell Biol 2022; 101:151248. [PMID: 35688054 PMCID: PMC11058851 DOI: 10.1016/j.ejcb.2022.151248] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2021] [Revised: 06/02/2022] [Accepted: 06/03/2022] [Indexed: 11/30/2022] Open
Abstract
Osteoclasts are bone resorbing cells that are responsible for physiological and pathological bone resorption. Macrophage colony stimulating factor (M-CSF) binds to the M-CSF receptor (c-FMS) and plays a key role in the differentiation and survival of macrophages and osteoclasts. THOC5, a member of the THO complex, has been shown to regulate hematopoiesis and M-CSF-induced macrophage differentiation. However, the role of THOC5 in osteoclasts remains unclear. Here, our study reveals a new role of THOC5 in osteoclast formation. We found that THOC5 shuttles between nucleus and cytoplasm in an M-CSF signaling dependent manner. THOC5 bound to FICD, a proteolytic cleavage product of c-FMS, and THOC5 facilitates the nuclear translocations of FICD. Decreased expression of THOC5 by siRNA-mediated knock down suppressed osteoclast differentiation, in part, by regulating RANK, a key receptor of osteoclasts. Mechanistically, knock down of THOC5 inhibited the expression of RANKL-induced FOS and NFATc1. Our findings highlight THOC5's function as a positive regulator of osteoclasts.
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Affiliation(s)
- Se Hwan Mun
- Arthritis and Tissue Degeneration Program, David Z. Rosensweig Genomics Research Center, Hospital for Special Surgery, New York, NY 10021, USA; Research Institute of Women's Health, Sookmyung Women's University, Seoul 04310, Republic of Korea
| | - Brian Oh
- Arthritis and Tissue Degeneration Program, David Z. Rosensweig Genomics Research Center, Hospital for Special Surgery, New York, NY 10021, USA
| | - Min Joon Lee
- Arthritis and Tissue Degeneration Program, David Z. Rosensweig Genomics Research Center, Hospital for Special Surgery, New York, NY 10021, USA
| | - Seyeon Bae
- Arthritis and Tissue Degeneration Program, David Z. Rosensweig Genomics Research Center, Hospital for Special Surgery, New York, NY 10021, USA; Department of Medicine, Weill Cornell Medical College, New York, NY 10065, USA
| | - Young Yang
- Research Institute of Women's Health, Sookmyung Women's University, Seoul 04310, Republic of Korea.
| | - Kyung-Hyun Park-Min
- Arthritis and Tissue Degeneration Program, David Z. Rosensweig Genomics Research Center, Hospital for Special Surgery, New York, NY 10021, USA; Department of Medicine, Weill Cornell Medical College, New York, NY 10065, USA; BCMB allied program, Weill Cornell Graduate School of Medical Sciences, New York, NY 10021, USA.
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Xie Y, Luo X, He H, Pan T, He Y. Identification of an individualized RNA binding protein-based prognostic signature for diffuse large B-cell lymphoma. Cancer Med 2021; 10:2703-2713. [PMID: 33749163 PMCID: PMC8026940 DOI: 10.1002/cam4.3859] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2021] [Revised: 02/19/2021] [Accepted: 03/08/2021] [Indexed: 12/19/2022] Open
Abstract
RNA binding proteins (RBPs) are increasingly appreciated as being essential for normal hematopoiesis and have a critical role in the progression of hematological malignancies. However, their functional consequences and clinical significance in diffuse large B‐cell lymphoma (DLBCL) remain unknown. Here, we conducted a systematic analysis to identify RBP‐related genes affecting DLBCL prognosis based on the Gene Expression Omnibus database. By univariate and multivariate Cox proportional hazards regression (CPHR) methods, six RBPs‐related genes (CMSS1, MAEL, THOC5, PSIP1, SNIP1, and ZCCHC7) were identified closely related to the overall survival (OS) of DLBCL patients. The RBPs signature could efficiently distinguished low‐risk from high‐risk patients and could serve as an independent and reliable factor for predicting OS. Moreover, Gene Set Enrichment Analysis revealed 17 significantly enriched pathways between high‐ versus low‐risk group, including the regulation of autophagy, chronic myeloid leukemia, NOTCH signaling pathway, and B cell receptor signaling pathway. Then we developed an RBP‐based nomogram combining other clinical risk factors. The receiver operating characteristic curve analysis demonstrated high prognostic predictive efficiency of this model with the area under the curve values were 0.820 and 0.780, respectively, in the primary set and entire set. In summary, our RBP‐based model could be a novel prognostic predictor and had the potential for developing treatment targets for DLBCL.
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Affiliation(s)
- Yongzhi Xie
- Department of Neurology, The Third Xiangya Hospital, Central South University, Changsha, China
| | - Ximei Luo
- School of Computer Science and Technology, Harbin Institute of Technology, Harbin, China
| | - Haiqing He
- Department of Urology, Second Xiangya Hospital, Central South University, Changsha, China
| | - Tao Pan
- Department of Lymphoma & Hematology, The Affiliated Tumor Hospital of Xiangya Medical School, Central South University, Changsha, China
| | - Yizi He
- Department of Lymphoma & Hematology, The Affiliated Tumor Hospital of Xiangya Medical School, Central South University, Changsha, China
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Whetton AD, Azmi NC, Pearson S, Jaworska E, Zhang L, Blance R, Kendall AC, Nicolaou A, Taylor S, Williamson AJ, Pierce A. MPL W515L expression induces TGFβ secretion and leads to an increase in chemokinesis via phosphorylation of THOC5. Oncotarget 2016; 7:10739-55. [PMID: 26919114 PMCID: PMC4905435 DOI: 10.18632/oncotarget.7639] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2016] [Accepted: 02/15/2016] [Indexed: 02/03/2023] Open
Abstract
The thrombopoietin receptor (MPL) has been shown to be mutated (MPL W515L) in myelofibrosis and thrombocytosis yet new approaches to treat this disorder are still required. We have previously shown that transcriptome and proteomic effects do not correlate well in oncogene-mediated leukemogenesis. We therefore investigated the effects of MPL W515L using proteomics. The consequences of MPL W515L expression on over 3300 nuclear and 3500 cytoplasmic proteins were assessed using relative quantification mass spectrometry. We demonstrate that MPL W515L expression markedly modulates the CXCL12/CXCR4/CD45 pathway associated with stem and progenitor cell chemotactic movement. We also demonstrated that MPL W515L expressing cells displayed increased chemokinesis which required the MPL W515L-mediated dysregulation of MYC expression via phosphorylation of the RNA transport protein THOC5 on tyrosine 225. In addition MPL W515L expression induced TGFβ secretion which is linked to sphingosine 1-phosphate production and the increased chemokinesis. These studies identify several pathways which offer potential targets for therapeutic intervention in the treatment of MPL W515L-driven malignancy. We validate our approach by showing that CD34+ cells from MPL W515L positive patients display increased chemokinesis and that treatment with a combination of MYC and sphingosine kinase inhibitors leads to the preferential killing of MPL W515L expressing cells.
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Affiliation(s)
- Anthony D. Whetton
- Stem Cell and Leukaemia Proteomics Laboratory, The University of Manchester, Manchester, UK
| | - Norhaida Che Azmi
- Stem Cell and Leukaemia Proteomics Laboratory, The University of Manchester, Manchester, UK
| | - Stella Pearson
- Stem Cell and Leukaemia Proteomics Laboratory, The University of Manchester, Manchester, UK
| | - Ewa Jaworska
- Stem Cell and Leukaemia Proteomics Laboratory, The University of Manchester, Manchester, UK
| | - Liqun Zhang
- Stem Cell and Leukaemia Proteomics Laboratory, The University of Manchester, Manchester, UK
| | - Rognvald Blance
- Stem Cell and Leukaemia Proteomics Laboratory, The University of Manchester, Manchester, UK
| | - Alexandra C. Kendall
- Manchester Pharmacy School, Faculty of Medical and Human Sciences, Manchester Academic Health Science Centre, The University of Manchester, Manchester, UK
| | - Anna Nicolaou
- Manchester Pharmacy School, Faculty of Medical and Human Sciences, Manchester Academic Health Science Centre, The University of Manchester, Manchester, UK
| | - Samuel Taylor
- Stem Cell and Leukaemia Proteomics Laboratory, The University of Manchester, Manchester, UK
| | - Andrew J.K. Williamson
- Stem Cell and Leukaemia Proteomics Laboratory, The University of Manchester, Manchester, UK
| | - Andrew Pierce
- Stem Cell and Leukaemia Proteomics Laboratory, The University of Manchester, Manchester, UK
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Depletion of three combined THOC5 mRNA export protein target genes synergistically induces human hepatocellular carcinoma cell death. Oncogene 2015; 35:3872-9. [PMID: 26549021 DOI: 10.1038/onc.2015.433] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2015] [Revised: 10/01/2015] [Accepted: 10/11/2015] [Indexed: 12/15/2022]
Abstract
Hepatocellular carcinoma (HCC) is a frequent form of cancer with a poor prognosis and with limited possibilities of medical intervention. It has been shown that over 100 putative driver genes are associated with multiple recurrently altered pathways in HCC, suggesting that multiple pathways will need to be inhibited for any therapeutic method. mRNA processing is regulated by a complex RNA-protein network that is essential for the maintenance of homeostasis. THOC5, a member of mRNA export complex, has a role in less than 1% of mRNA processing, and is required for cell growth and differentiation, but not for cell survival in normal fibroblasts, hepatocytes and macrophages. In this report, we show that 50% depletion of THOC5 in human HCC cell lines Huh7 and HepG2 induced apoptosis. Transcriptome analysis using THOC5-depleted cells revealed that 396 genes, such as transmembrane BAX inhibitor motif containing 4 (TMBIM4), transmembrane emp24-like trafficking protein 10 (Tmed10) and D-tyrosyl-tRNA deacylase 2 (Dtd2) genes were downregulated in both cell lines. The depletion of one of these THOC5 target genes in Huh7 or HepG2 did not significantly induce cell death, suggesting that these may be fine tuners for HCC cell survival. However, the depletion of a combination of these genes synergistically increased the number of TUNEL (terminal deoxynucleotidyl transferase dUTP nick end labeling)-positive HCC. It must be noted that the depletion of these genes did not induce cell death in the hepatocyte cell line, THLE-2 cells. THOC5 expression was enhanced in 78% of cytological differentiation grading G2 and G3 tumor in primary HCC. Furthermore, the expression of a putative glycoprotein, Tmed10, is correlated to THOC5 expression level in primary HCCs, suggesting that this protein may be a novel biomarker for HCC. These data imply that the suppression of the multiple THOC5 target genes may represent a novel strategy for HCC therapy.
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Tran DDH, Koch A, Tamura T. THOC5, a member of the mRNA export complex: a novel link between mRNA export machinery and signal transduction pathways in cell proliferation and differentiation. Cell Commun Signal 2014; 12:3. [PMID: 24410813 PMCID: PMC3899923 DOI: 10.1186/1478-811x-12-3] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2013] [Accepted: 01/06/2014] [Indexed: 11/10/2022] Open
Abstract
Cell growth, differentiation, and commitment to a restricted lineage are guided by a timely expressed set of growth factor/cytokine receptors and their down-stream transcription factor genes. Transcriptional control mechanisms of gene expression during differentiation have been mainly studied by focusing on the cis- and trans-elements in promoters however, the role of mRNA export machinery during differentiation has not been adequately examined. THO (Suppressors of the transcriptional defects of hpr1 delta by overexpression) complex 5 (THOC5) is a member of THO complex which is a subcomplex of the transcription/export complex (TREX). THOC5 is evolutionarily conserved in higher eukaryotes, however the exact roles of THOC5 in transcription and mRNA export are still unclear. In this review, we focus on recently uncovered aspects of the role of THOC5 in signal transduction induced by extracellular stimuli. THOC5 is phosphorylated by several protein kinases at multiple residues upon extracellular stimuli. These include stimulation with growth factors/cytokines/chemokines, or DNA damage reagents. Furthermore, THOC5 is a substrate for several oncogenic tyrosine kinases, suggesting that THOC5 may be involved in cancer development. Recent THOC5 knockout mouse data reveal that THOC5 is an essential element in the maintenance of stem cells and growth factor/cytokine-mediated differentiation/proliferation. Furthermore, depletion of THOC5 influences less than 1% of total mRNA export in the steady state, however it influences more than 90% of growth factor/cytokine induced genes. THOC5, thereby contributes to the 3' processing and/or export of immediate-early genes induced by extracellular stimuli. These studies bring new insight into the link between the mRNA export complex and immediate-early gene response. The data from these studies also suggest that THOC5 may be a useful tool for studying stem cell biology, for modifying the differentiation processes and for cancer therapy.
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Affiliation(s)
| | | | - Teruko Tamura
- Institut fuer Biochemie, OE4310, Medizinische Hochschule Hannover, Carl-Neuberg-Str, 1, D-30623, Hannover, Germany.
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Saran S, Tran DDH, Klebba-Färber S, Moran-Losada P, Wiehlmann L, Koch A, Chopra H, Pabst O, Hoffmann A, Klopfleisch R, Tamura T. THOC5, a member of the mRNA export complex, contributes to processing of a subset of wingless/integrated (Wnt) target mRNAs and integrity of the gut epithelial barrier. BMC Cell Biol 2013; 14:51. [PMID: 24267292 PMCID: PMC4222586 DOI: 10.1186/1471-2121-14-51] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2013] [Accepted: 11/19/2013] [Indexed: 11/26/2022] Open
Abstract
Background THO (Suppressors of the transcriptional defects of hpr1 delta by overexpression) complex 5 (THOC5), an mRNA export protein, is involved in the expression of only 1% of all genes. Using an interferon inducible knockout mouse system, we have previously shown that THOC5 is an essential element in the maintenance of hematopoietic stem cells and cytokine-mediated hematopoiesis in adult mice. Here we interrogate THOC5 function in cell differentiation beyond the hematopoietic system and study pathological changes caused by THOC5 deficiency. Results To examine whether THOC5 plays a role in general differentiation processes, we generated tamoxifen inducible THOC5 knockout mice. We show here that the depletion of THOC5 impaired not only hematopoietic differentiation, but also differentiation and self renewal of the gut epithelium. Depletion of the THOC5 gene did not cause pathological alterations in liver or kidney. We further show that THOC5 is indispensable for processing of mRNAs induced by Wnt (wingless/integrated) signaling which play key roles in epithelial cell differentiation/proliferation. A subset of Wnt target mRNAs, SRY-box containing gene 9 (Sox9), and achaete-scute complex homolog 2 (Ascl2), but not Fibronectin 1 (Fn1), were down-regulated in THOC5 knockout intestinal cells. The down-regulated Wnt target mRNAs were able to bind to THOC5. Furthermore, pathological alterations in the gastrointestinal tract induced translocation of intestinal bacteria and caused sepsis in mice. The bacteria translocation may cause Toll-like receptor activation. We identified one of the Toll-like receptor inducible genes, prostaglandin-endoperoxidase synthase 2 (Ptgs2 or COX2) transcript as THOC5 target mRNA. Conclusion THOC5 is indispensable for processing of only a subset of mRNAs, but plays a key role in processing of mRNAs inducible by Wnt signals. Furthermore, THOC5 is dispensable for general mRNA export in terminally differentiated organs, indicating that multiple mRNA export pathways exist. These data imply that THOC5 may be a useful tool for studying intestinal stem cells, for modifying the differentiation processes and for cancer therapy.
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Affiliation(s)
- Shashank Saran
- Institut fuer Biochemie, Medizinische Hochschule Hannover, OE4310 Carl-Neuberg-Str, 1, Hannover D-30623, Germany.
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7
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Tran DDH, Saran S, Dittrich-Breiholz O, Williamson AJK, Klebba-Färber S, Koch A, Kracht M, Whetton AD, Tamura T. Transcriptional regulation of immediate-early gene response by THOC5, a member of mRNA export complex, contributes to the M-CSF-induced macrophage differentiation. Cell Death Dis 2013; 4:e879. [PMID: 24157873 PMCID: PMC3920956 DOI: 10.1038/cddis.2013.409] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2013] [Revised: 09/19/2013] [Accepted: 09/19/2013] [Indexed: 12/12/2022]
Abstract
Hematopoiesis and commitment to a restricted lineage are guided by a timely expressed set of cytokine receptors and their downstream transcription factors. A member of the mRNA export complex, THOC5 (suppressors of the transcriptional defects of hpr1 delta by overexpression complex 5) is a substrate for several tyrosine kinases such as macrophage colony-stimulating factor (M-CSF) receptor and various leukemogenic tyrosine kinases, such as Bcr-Abl, or NPM-ALK. THOC5 tyrosine phosphorylation is elevated in stem cells from patients with chronic myeloid leukemia, suggesting that THOC5 may be involved in leukemia development. THOC5 is also an essential element in the maintenance of hematopoiesis in adult mice. In this report, we show that THOC5 is located in the nuclear speckles, and that it is translocated from the nucleus to cytoplasm during M-CSF-induced bone marrow-derived macrophage differentiation. Furthermore, we have identified THOC5 target genes by trancriptome analysis, using tamoxifen-inducible THOC5 knockout macrophages. Although only 99 genes were downregulated in THOC5-depleted macrophages, half of the genes are involved in differentiation and/or migration. These include well-known regulators of myeloid differentiation inhibitor of DNA binding (Id)1, Id3, Smad family member 6 (Smad6) and Homeobox (Hox)A1. In addition, a subset of M-CSF-inducible genes, such as Ets family mRNAs are THOC5 target mRNAs. Upon depletion of THOC5, unspliced v-ets erythroblastosis virus E26 oncogene homolog (Ets1) mRNA was accumulated in the nucleus. Furthermore, THOC5 was recruited to chromatin where Ets1 was transcribed and bound to unspliced and spliced Ets1 transcripts, indicating that THOC5 has a role in processing/export of M-CSF-inducible genes. In conclusion, regulation of immediate-early gene response by THOC5, a member of mRNA export complex contributes to the M-CSF-induced macrophage differentiation.
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Affiliation(s)
- D D H Tran
- Institut fuer Biochemie, OE4310, Medizinische Hochschule Hannover, Carl-Neuberg-Street 1, Hannover D-30623, Germany
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8
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A pathway from leukemogenic oncogenes and stem cell chemokines to RNA processing via THOC5. Leukemia 2012; 27:932-40. [PMID: 23032722 DOI: 10.1038/leu.2012.283] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
THOC5 is a member of the THO complex that is involved in processing and transport of mRNA. We have shown previously that hematopoietic stem cells have an absolute requirement for THOC5 for survival and that THOC5 is phosphorylated on tyrosine 225 as a consequence of leukemogenic protein tyrosine kinase (PTK) action. We have investigated pathways for THOC5 phosphorylation to develop an understanding of THO complex modulation by tyrosine kinase (TK) oncogenes in leukemias. We demonstrate that THOC5 phosphorylation is mediated by Src PTK and CD45 protein tyrosine phosphatase action and that this event is sensitive to oxidative status. We show that THOC5 phosphorylation is elevated in stem cells from patients with chronic myeloid leukemia (CML) and that this phosphorylation is sensitive to the frontline drugs used in CML treatment. Further we show that THOC5 Y225 phosphorylation governs mRNA binding. In addition, CXCL12 is shown to induce THOC5 Y225 phosphorylation, and site-directed mutagenesis demonstrates that this modulates motile response. In conclusion, we delineate a signaling pathway stimulated by leukemogenic PTKs, chemokines and oxidative stress that can affect THO complex mediation of gene expression describing mechanisms for post-transcriptional regulation of protein levels.
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Luna R, Rondón AG, Aguilera A. New clues to understand the role of THO and other functionally related factors in mRNP biogenesis. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2011; 1819:514-20. [PMID: 22207203 DOI: 10.1016/j.bbagrm.2011.11.012] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2011] [Revised: 11/24/2011] [Accepted: 11/29/2011] [Indexed: 02/02/2023]
Abstract
Coupling of transcription with mRNA processing and export has been shown to be relevant to efficient gene expression. A number of studies have determined that THO/TREX, a nuclear protein complex conserved from yeast to humans, plays an important role in mRNP biogenesis connecting transcription elongation, mRNA export and preventing genetic instability. Recent data indicates that THO could be relevant to different mRNA processing steps, including the 3'-end formation, transcript release and export. Novel connections of THO to proteins related to the splicing machinery, provide new views about possible functions of THO in mRNP biogenesis. In this review, we summarize the previous and new results concerning the impact of THO in transcription and its biological implications, with a special emphasis on the relationship with THSC/TREX-2 and other functionally related factors involved in mRNA biogenesis and export. The emerging picture presents THO as a dynamic complex interacting with the nascent RNA and with different factors connecting nuclear functions necessary for mRNP biogenesis with genome integrity, cellular homeostasis and development. This article is part of a Special Issue entitled: Nuclear Transport and RNA Processing.
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Affiliation(s)
- Rosa Luna
- Centro Andaluz de Biología Molecular y Medicina Regenerativa CABIMER, Universidad de Sevilla-CSIC, Av Américo Vespucio s/n, 41092 Sevilla, Spain. rlvarp@is/es
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Ramachandran S, Tran DDH, Klebba-Faerber S, Kardinal C, Whetton AD, Tamura T. An ataxia-telangiectasia-mutated (ATM) kinase mediated response to DNA damage down-regulates the mRNA-binding potential of THOC5. RNA (NEW YORK, N.Y.) 2011; 17:1957-1966. [PMID: 21937706 PMCID: PMC3198589 DOI: 10.1261/rna.2820911] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
In response to DNA damage, transcription is blocked by inhibition of RNA polymerase II activity. The regulation of a preexisting pool of mRNAs, therefore, plays a key role in DNA repair, cell cycle arrest, or inhibition of differentiation. THOC5 is a member of the THO complex and plays a role in the export of a subset of mRNA, which plays an important role in hematopoiesis and maintaining primitive cells. Since three serine residues in the PEST domain of THOC5 have been shown to be directly phosphorylated by ataxia-telangiectasia-mutated (ATM) kinase, we examined the THOC5-dependent mRNA export under DNA damage. We show here that DNA damage drastically decreased the cytoplasmic pool of a set of THOC5-dependent mRNAs and impaired the THOC5/mRNA complex formation. The mRNP complex formed with nonphosphorylation mutant (S307/312/314A) THOC5, but not with a C-terminal deletion mutant after DNA damage, suggesting that the C-terminal domain of THOC5, but not its phosphorylation in the PEST domain, is necessary for the regulation of the mRNA-binding potency of THOC5. The cytoplasmic THOC5-dependent mRNAs were recovered by treatment with ATM kinase-specific or p53-specific siRNA, as well as by treatment with ATM kinase inhibitor, KU55933, under DNA damage conditions, suggesting that the ATM-kinase-p53 pathway is involved in this response to the DNA damage. Furthermore, the treatment with KU55933 blocked DNA damage-induced THOC5mRNP complex dissociation, indicating that activation of ATM kinase suppresses the ability of THOC5 to bind to its target mRNAs.
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Affiliation(s)
- Sheetal Ramachandran
- Institut für Biochemie, OE4310, Medizinische Hochschule Hannover, D-30623 Hannover, Germany
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11
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Guria A, Tran DDH, Ramachandran S, Koch A, El Bounkari O, Dutta P, Hauser H, Tamura T. Identification of mRNAs that are spliced but not exported to the cytoplasm in the absence of THOC5 in mouse embryo fibroblasts. RNA (NEW YORK, N.Y.) 2011; 17:1048-56. [PMID: 21525145 PMCID: PMC3096037 DOI: 10.1261/rna.2607011] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2010] [Accepted: 03/09/2011] [Indexed: 05/23/2023]
Abstract
The TREX (transcription/export) complex has been conserved throughout evolution from yeast to man and is required for coupled transcription elongation and nuclear export of mRNAs. The TREX complex in mammals and Drosophila is composed of the THO subcomplex (THOC1, THOC2, THOC5, THOC6, and THOC7), THOC3, UAP56, and Aly/THOC4. In human and Drosophila, various studies have shown that THO is required for the export of heat shock mRNAs, but nothing is known about other mRNAs. Our previous study using conditional THOC5 (or FMIP) knockout mice revealed that the presence of THOC5 is critical in hematopoietic cells but not for terminally differentiated cells. In this study, we describe the establishment of a mouse embryo fibroblast cell line (MEF), THOC5 flox/flox. Four days after infection of MEF THOC5 flox/flox with adenovirus carrying Cre-recombinase gene (Ad-GFP-Cre), THOC5 is down-regulated >95% at the protein level, and cell growth is strongly suppressed. Transcriptome analysis using cytoplasmic RNA isolated from cells lacking functional THOC5 reveals that only 2.9% of all genes were down-regulated more than twofold. Although we examined these genes in fibroblasts, one-fifth of all down-regulated genes (including HoxB3 and polycomb CBX2) are known to play a key role in hematopoietic development. We further identified 10 genes that are spliced but not exported to the cytoplasm in the absence of THOC5. These mRNAs were copurified with THOC5. Furthermore, Hsp70 mRNA was exported in the absence of THOC5 at 37°C, but not under heat shock condition (42°C), suggesting that THOC5 may be required for mRNA export under stress and/or upon signaling-induced conditions.
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Affiliation(s)
- Anuja Guria
- Institut für Biochemie, OE4310, Medizinische Hochschule Hannover, D-30623 Hannover, Germany
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12
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A sensitive mass spectrometric method for hypothesis-driven detection of peptide post-translational modifications: multiple reaction monitoring-initiated detection and sequencing (MIDAS). Nat Protoc 2009; 4:870-7. [PMID: 19444244 DOI: 10.1038/nprot.2009.57] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The application of a targeted mass spectrometric workflow to the sensitive identification of post-translational modifications is described. This protocol employs multiple reaction monitoring (MRM) to search for all putative peptides specifically modified in a target protein. Positive MRMs trigger an MS/MS experiment to confirm the nature and site of the modification. This approach, termed MIDAS (MRM-initiated detection and sequencing), is more sensitive than approaches using neutral loss scanning or precursor ion scanning methodologies, due to a more efficient use of duty cycle along with a decreased background signal associated with MRM. We describe the use of MIDAS for the identification of phosphorylation, with a typical experiment taking just a couple of hours from obtaining a peptide sample. With minor modifications, the MIDAS method can be applied to other protein modifications or unmodified peptides can be used as a MIDAS target.
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El Bounkari O, Guria A, Klebba-Faerber S, Claussen M, Pieler T, Griffiths JR, Whetton AD, Koch A, Tamura T. Nuclear localization of the pre-mRNA associating protein THOC7 depends upon its direct interaction with Fms tyrosine kinase interacting protein (FMIP). FEBS Lett 2008; 583:13-8. [PMID: 19059247 DOI: 10.1016/j.febslet.2008.11.024] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2008] [Revised: 11/06/2008] [Accepted: 11/07/2008] [Indexed: 10/21/2022]
Abstract
THOC7 and Fms-interacting protein (FMIP) are members of the THO complex that associate with the mRNA export apparatus. FMIP is a nucleocytoplasmic shuttling protein with a nuclear localization signal (NLS), whereas THOC7 does not contain a typical NLS motif. We show here that THOC7 (50-137, amino acid numbers) binds to the N-terminal portion (1-199) of FMIP directly. FMIP is detected mainly in the nucleus. In the absence of exogenous FMIP, THOC7 resides mainly in the cytoplasm, while in the presence of FMIP, THOC7 is transported into the nucleus with FMIP. Furthermore, THOC7 lacking the FMIP binding site does not co-localize with FMIP, indicating that THOC7/FMIP interaction is required for nuclear localization of THOC7.
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Affiliation(s)
- Omar El Bounkari
- Institut fuer Biochemie, OE4310 Medizinische Hochschule Hannover, Hannover, Germany
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Carney L, Pierce A, Rijnen M, Gonzalez Sanchez MB, Hamzah HG, Zhang L, Tamura T, Whetton AD. THOC5 couples M-CSF receptor signaling to transcription factor expression. Cell Signal 2008; 21:309-16. [PMID: 19015024 DOI: 10.1016/j.cellsig.2008.10.018] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2008] [Revised: 10/24/2008] [Accepted: 10/24/2008] [Indexed: 10/21/2022]
Abstract
THOC5 is a nuclear/cytoplasmic protein member of the spliceosome complex which potentiates C/EBP expression in adipocyte differentiation. As C/EBP family members are important regulators of myelopoiesis and THOC5 is highly expressed in neutrophil/macrophage progenitor cells we assessed the role of THOC5 in cytokine-stimulated monocytic development. M-CSF stimulated maturation of the NFS60 cell line was associated with enhanced THOC5 expression and phosphorylation. THOC5 was also shown to form a complex with C/EBPbeta. Ectopic expression of THOC5 mimicked M-CSF mediated cell maturation and enhanced protein expression of the myeloid transcription factors C/EBPbeta, C/EBPalpha, Pu-1 and also GAB2 (a PI-3 Kinase and macrophage development regulator). Increased THOC5 expression also mimicked M-CSF stimulated increases in the lipid second messenger PtdInsP(3). Inhibition of THOC5-induced increases in PtdInsP(3) levels abrogated the elevated levels of C/EBPbeta. Thus THOC5 expression can potentiate receptor signalling to transcription factor expression and monocyte differentiation.
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Affiliation(s)
- Louise Carney
- Stem Cell and Leukaemia Proteomics laboratory, Faculty of Medical and Human Sciences, University of Manchester, Christie Hospital, Wilmslow Road, Manchester M20 9BX, UK
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