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Lenarcic EM, Moorman NJ. The Host DHX29 RNA Helicase Regulates HCMV Immediate Early Protein Synthesis. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2025:2025.01.27.635168. [PMID: 39975304 PMCID: PMC11838274 DOI: 10.1101/2025.01.27.635168] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/21/2025]
Abstract
The dead box helicase DHX29 plays a critical role in the translation of mRNAs containing complex RNA secondary structure in their 5' untranslated regions. The human cytomegalovirus (HCMV) genome has a high GC content, suggesting the 5'UTRs of viral mRNAs may contain significant secondary structure and require DHX29 for their efficient translation initiation. We found that depleting DHX29 from primary human fibroblasts prior to infection reduced viral mRNA and protein levels and decreased HCMV replication. The defect in HCMV replication correlated with decreased expression of the HCMV immediate early proteins IE1 and IE2, which are necessary for the establishment of lytic infection. Analysis of polysome associated mRNAs revealed that the defect in IE1 and IE2 expression is due to decreased mRNA translation efficiency. We found that DHX29 depletion led to reduced levels of the eIF4F translation initiation complex, resulting from decreased translation of the eIF4G mRNA. However, in line with our previous results showing a minimal role for the eIF4F complex in HCMV mRNA translation, we found that depleting eIF4G prior to infection did not impact IE1 and IE2 translation. Together our results define a new role for DHX29 in regulating eIF4F-dependent translation and identify a critical role for DHX29 in the translation of HCMV mRNAs. Significance Expression of the HCMV immediate early proteins IE1 and IE2 is critical for the establishment of lytic replication and the reactivation of latent HCMV infections. Defining the mechanisms controlling HCMV IE1 and IE2 protein expression has the potential to identify new strategies for therapeutic interventions that can limit HCMV disease in immune naïve and immune compromised individuals. Our finding that the cellular DHX29 helicase is necessary for the efficient translation of mRNAs encoding IE1 and IE2 suggests that therapies that inhibit DHX29 could potentially be useful in treating HCMV disease and adds to the growing body of literature suggesting DHX29 activity is a disease driver in multiple indications including viral disease, inflammation and cancer.
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Martín-Villanueva S, Galmozzi CV, Ruger-Herreros C, Kressler D, de la Cruz J. The Beak of Eukaryotic Ribosomes: Life, Work and Miracles. Biomolecules 2024; 14:882. [PMID: 39062596 PMCID: PMC11274626 DOI: 10.3390/biom14070882] [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: 06/19/2024] [Revised: 07/19/2024] [Accepted: 07/21/2024] [Indexed: 07/28/2024] Open
Abstract
Ribosomes are not totally globular machines. Instead, they comprise prominent structural protrusions and a myriad of tentacle-like projections, which are frequently made up of ribosomal RNA expansion segments and N- or C-terminal extensions of ribosomal proteins. This is more evident in higher eukaryotic ribosomes. One of the most characteristic protrusions, present in small ribosomal subunits in all three domains of life, is the so-called beak, which is relevant for the function and regulation of the ribosome's activities. During evolution, the beak has transitioned from an all ribosomal RNA structure (helix h33 in 16S rRNA) in bacteria, to an arrangement formed by three ribosomal proteins, eS10, eS12 and eS31, and a smaller h33 ribosomal RNA in eukaryotes. In this review, we describe the different structural and functional properties of the eukaryotic beak. We discuss the state-of-the-art concerning its composition and functional significance, including other processes apparently not related to translation, and the dynamics of its assembly in yeast and human cells. Moreover, we outline the current view about the relevance of the beak's components in human diseases, especially in ribosomopathies and cancer.
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Affiliation(s)
- Sara Martín-Villanueva
- Instituto de Biomedicina de Sevilla, Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, E-41013 Seville, Spain; (S.M.-V.); (C.V.G.); (C.R.-H.)
- Departamento de Genética, Facultad de Biología, Universidad de Sevilla, E-41012 Seville, Spain
| | - Carla V. Galmozzi
- Instituto de Biomedicina de Sevilla, Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, E-41013 Seville, Spain; (S.M.-V.); (C.V.G.); (C.R.-H.)
- Departamento de Genética, Facultad de Biología, Universidad de Sevilla, E-41012 Seville, Spain
| | - Carmen Ruger-Herreros
- Instituto de Biomedicina de Sevilla, Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, E-41013 Seville, Spain; (S.M.-V.); (C.V.G.); (C.R.-H.)
- Departamento de Genética, Facultad de Biología, Universidad de Sevilla, E-41012 Seville, Spain
| | - Dieter Kressler
- Department of Biology, University of Fribourg, CH-1700 Fribourg, Switzerland;
| | - Jesús de la Cruz
- Instituto de Biomedicina de Sevilla, Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla, E-41013 Seville, Spain; (S.M.-V.); (C.V.G.); (C.R.-H.)
- Departamento de Genética, Facultad de Biología, Universidad de Sevilla, E-41012 Seville, Spain
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van den Akker GGH, Chabronova A, Housmans BAC, van der Vloet L, Surtel DAM, Cremers A, Marchand V, Motorin Y, Caron MMJ, Peffers MJ, Welting TJM. TGF-β2 Induces Ribosome Activity, Alters Ribosome Composition and Inhibits IRES-Mediated Translation in Chondrocytes. Int J Mol Sci 2024; 25:5031. [PMID: 38732249 PMCID: PMC11084827 DOI: 10.3390/ijms25095031] [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: 03/12/2024] [Revised: 04/29/2024] [Accepted: 05/01/2024] [Indexed: 05/13/2024] Open
Abstract
Alterations in cell fate are often attributed to (epigenetic) regulation of gene expression. An emerging paradigm focuses on specialized ribosomes within a cell. However, little evidence exists for the dynamic regulation of ribosome composition and function. Here, we stimulated a chondrocytic cell line with transforming growth factor beta (TGF-β2) and mapped changes in ribosome function, composition and ribosomal RNA (rRNA) epitranscriptomics. 35S Met/Cys incorporation was used to evaluate ribosome activity. Dual luciferase reporter assays were used to assess ribosomal modus. Ribosomal RNA expression and processing were determined by RT-qPCR, while RiboMethSeq and HydraPsiSeq were used to determine rRNA modification profiles. Label-free protein quantification of total cell lysates, isolated ribosomes and secreted proteins was done by LC-MS/MS. A three-day TGF-β2 stimulation induced total protein synthesis in SW1353 chondrocytic cells and human articular chondrocytes. Specifically, TGF-β2 induced cap-mediated protein synthesis, while IRES-mediated translation was not (P53 IRES) or little affected (CrPv IGR and HCV IRES). Three rRNA post-transcriptional modifications (PTMs) were affected by TGF-β2 stimulation (18S-Gm1447 downregulated, 18S-ψ1177 and 28S-ψ4598 upregulated). Proteomic analysis of isolated ribosomes revealed increased interaction with eIF2 and tRNA ligases and decreased association of eIF4A3 and heterogeneous nuclear ribonucleoprotein (HNRNP)s. In addition, thirteen core ribosomal proteins were more present in ribosomes from TGF-β2 stimulated cells, albeit with a modest fold change. A prolonged stimulation of chondrocytic cells with TGF-β2 induced ribosome activity and changed the mode of translation. These functional changes could be coupled to alterations in accessory proteins in the ribosomal proteome.
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Affiliation(s)
- Guus G. H. van den Akker
- Laboratory of Experimental Orthopedics, Department of Orthopedic Surgery, Research School CAPHRI, Faculty of Healthy Medicine and Life Sciences, Maastricht University, 6229 ER Maastricht, The Netherlands; (A.C.); (M.M.J.C.); (T.J.M.W.)
| | - Alzbeta Chabronova
- Laboratory of Experimental Orthopedics, Department of Orthopedic Surgery, Research School CAPHRI, Faculty of Healthy Medicine and Life Sciences, Maastricht University, 6229 ER Maastricht, The Netherlands; (A.C.); (M.M.J.C.); (T.J.M.W.)
- Department of Musculoskeletal Ageing Science, Institute of Life Course and Medical Sciences, University of Liverpool, Liverpool L7 8TX, UK
| | - Bas A. C. Housmans
- Laboratory of Experimental Orthopedics, Department of Orthopedic Surgery, Research School CAPHRI, Faculty of Healthy Medicine and Life Sciences, Maastricht University, 6229 ER Maastricht, The Netherlands; (A.C.); (M.M.J.C.); (T.J.M.W.)
| | - Laura van der Vloet
- Laboratory of Experimental Orthopedics, Department of Orthopedic Surgery, Research School CAPHRI, Faculty of Healthy Medicine and Life Sciences, Maastricht University, 6229 ER Maastricht, The Netherlands; (A.C.); (M.M.J.C.); (T.J.M.W.)
| | - Don A. M. Surtel
- Laboratory of Experimental Orthopedics, Department of Orthopedic Surgery, Research School CAPHRI, Faculty of Healthy Medicine and Life Sciences, Maastricht University, 6229 ER Maastricht, The Netherlands; (A.C.); (M.M.J.C.); (T.J.M.W.)
| | - Andy Cremers
- Laboratory of Experimental Orthopedics, Department of Orthopedic Surgery, Research School CAPHRI, Faculty of Healthy Medicine and Life Sciences, Maastricht University, 6229 ER Maastricht, The Netherlands; (A.C.); (M.M.J.C.); (T.J.M.W.)
| | - Virginie Marchand
- UAR2008 IBSLor CNRS-INSERM, Université de Lorraine, BioPole, F54000 Nancy, France; (V.M.); (Y.M.)
| | - Yuri Motorin
- UAR2008 IBSLor CNRS-INSERM, Université de Lorraine, BioPole, F54000 Nancy, France; (V.M.); (Y.M.)
- UMR7365 IMoPA, CNRS, Université de Lorraine, BioPole, F54000 Nancy, France
| | - Marjolein M. J. Caron
- Laboratory of Experimental Orthopedics, Department of Orthopedic Surgery, Research School CAPHRI, Faculty of Healthy Medicine and Life Sciences, Maastricht University, 6229 ER Maastricht, The Netherlands; (A.C.); (M.M.J.C.); (T.J.M.W.)
| | - Mandy J. Peffers
- Department of Musculoskeletal Ageing Science, Institute of Life Course and Medical Sciences, University of Liverpool, Liverpool L7 8TX, UK
| | - Tim J. M. Welting
- Laboratory of Experimental Orthopedics, Department of Orthopedic Surgery, Research School CAPHRI, Faculty of Healthy Medicine and Life Sciences, Maastricht University, 6229 ER Maastricht, The Netherlands; (A.C.); (M.M.J.C.); (T.J.M.W.)
- Laboratory of Experimental Orthopedics, Department of Orthopedic Surgery, Maastricht University Medical Center +, 6229 HX Maastricht, The Netherlands
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Bowazolo C, Morse D. Insights into daily metabolic changes of the dinoflagellate Lingulodinium from ribosome profiling. Cell Cycle 2023; 22:1343-1352. [PMID: 37125841 PMCID: PMC10228409 DOI: 10.1080/15384101.2023.2206771] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2023] [Revised: 02/15/2023] [Accepted: 02/16/2023] [Indexed: 05/02/2023] Open
Abstract
The dinoflagellate Lingulodinium specializes its metabolism to perform different tasks better at specific times of day. For example, cells are specialized for photosynthesis during the day and bioluminescence and cell division at night. These rhythms are circadian as they are controlled by an endogenous circadian clock whose mechanism is currently unknown. Despite this, the metabolic rhythms follow coordinated changes in gene expression that occur at a translational level. These changes are revealed by ribosome profiling, a surrogate measure of protein synthesis rates in vivo. Lingulodinium regulates the synthesis rate of over three thousand transcripts. Peak synthesis rates for the different transcripts are clustered around three different times over a light/dark cycle. Furthermore, transcripts involved in the same metabolic process are coordinately regulated. We review the basic principles underlying the correlation of coordinated translation of cell metabolic pathway enzymes with known circadian rhythms, and offer examples where previously unsuspected rhythms are suggested by synchronized changes in gene expression.
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Affiliation(s)
- Carl Bowazolo
- Institut de Recherche en biologie Végétale, Département de Sciences Biologiques, Université de Montréal, Montréal, Québec, Canada
| | - David Morse
- Institut de Recherche en biologie Végétale, Département de Sciences Biologiques, Université de Montréal, Montréal, Québec, Canada
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Lockd promotes myoblast proliferation and muscle regeneration via binding with DHX36 to facilitate 5' UTR rG4 unwinding and Anp32e translation. Cell Rep 2022; 39:110927. [PMID: 35675771 DOI: 10.1016/j.celrep.2022.110927] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Revised: 02/10/2022] [Accepted: 05/18/2022] [Indexed: 11/20/2022] Open
Abstract
Adult muscle stem cells, also known as satellite cells (SCs), play pivotal roles in muscle regeneration, and long non-coding RNA (lncRNA) functions in SCs remain largely unknown. Here, we identify a lncRNA, Lockd, which is induced in activated SCs upon acute muscle injury. We demonstrate that Lockd promotes SC proliferation; deletion of Lockd leads to cell-cycle arrest, and in vivo repression of Lockd in mouse muscles hinders regeneration process. Mechanistically, we show that Lockd directly interacts with RNA helicase DHX36 and the 5'end of Lockd possesses the strongest binding with DHX36. Furthermore, we demonstrate that Lockd stabilizes the interaction between DHX36 and EIF3B proteins; synergistically, this complex unwinds the RNA G-quadruplex (rG4) structure formed at Anp32e mRNA 5' UTR and promotes the translation of ANP32E protein, which is required for myoblast proliferation. Altogether, our findings identify a regulatory Lockd/DHX36/Anp32e axis that promotes myoblast proliferation and acute-injury-induced muscle regeneration.
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Sweeney TR, Dhote V, Guca E, Hellen CUT, Hashem Y, Pestova T. Functional role and ribosomal position of the unique N-terminal region of DHX29, a factor required for initiation on structured mammalian mRNAs. Nucleic Acids Res 2021; 49:12955-12969. [PMID: 34883515 PMCID: PMC8682770 DOI: 10.1093/nar/gkab1192] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Revised: 11/12/2021] [Accepted: 11/22/2021] [Indexed: 02/05/2023] Open
Abstract
Translation initiation on structured mammalian mRNAs requires DHX29, a DExH protein that comprises a unique 534-aa-long N-terminal region (NTR) and a common catalytic DExH core. DHX29 binds to 40S subunits and possesses 40S-stimulated NTPase activity essential for its function. In the cryo-EM structure of DHX29-bound 43S preinitiation complexes, the main DHX29 density resides around the tip of helix 16 of 18S rRNA, from which it extends through a linker to the subunit interface forming an intersubunit domain next to the eIF1A binding site. Although a DExH core model can be fitted to the main density, the correlation between the remaining density and the NTR is unknown. Here, we present a model of 40S-bound DHX29, supported by directed hydroxyl radical cleavage data, showing that the intersubunit domain comprises a dsRNA-binding domain (dsRBD, aa 377-448) whereas linker corresponds to the long α-helix (aa 460-512) that follows the dsRBD. We also demonstrate that the N-terminal α-helix and the following UBA-like domain form a four-helix bundle (aa 90-166) that constitutes a previously unassigned section of the main density and resides between DHX29's C-terminal α-helix and the linker. In vitro reconstitution experiments revealed the critical and specific roles of these NTR elements for DHX29's function.
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Affiliation(s)
- Trevor R Sweeney
- Correspondence may also be addressed to Trevor R. Sweeney. Tel: +44 1483232441; Fax: +44 1483232448;
| | | | - Ewelina Guca
- INSERM U1212 Acides nucléiques : Régulations Naturelle et Artificielle (ARNA), Institut Européen de Chimie et Biologie, Université de Bordeaux, Pessac 33607, France
| | - Christopher U T Hellen
- Department of Cell Biology, SUNY Downstate Health Sciences University, 450 Clarkson Avenue, MSC 44, Brooklyn, NY 11203, USA
| | - Yaser Hashem
- Correspondence may also be addressed to Yaser Hashem. Tel: +33 5 40 00 88 22;
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Brito Querido J, Sokabe M, Kraatz S, Gordiyenko Y, Skehel JM, Fraser CS, Ramakrishnan V. Structure of a human 48 S translational initiation complex. Science 2020; 369:1220-1227. [PMID: 32883864 DOI: 10.1126/science.aba4904] [Citation(s) in RCA: 146] [Impact Index Per Article: 29.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2019] [Accepted: 07/07/2020] [Indexed: 12/20/2022]
Abstract
A key step in translational initiation is the recruitment of the 43S preinitiation complex by the cap-binding complex [eukaryotic initiation factor 4F (eIF4F)] at the 5' end of messenger RNA (mRNA) to form the 48S initiation complex (i.e., the 48S). The 48S then scans along the mRNA to locate a start codon. To understand the mechanisms involved, we used cryo-electron microscopy to determine the structure of a reconstituted human 48S The structure reveals insights into early events of translation initiation complex assembly, as well as how eIF4F interacts with subunits of eIF3 near the mRNA exit channel in the 43S The location of eIF4F is consistent with a slotting model of mRNA recruitment and suggests that downstream mRNA is unwound at least in part by being "pulled" through the 40S subunit during scanning.
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Affiliation(s)
| | - Masaaki Sokabe
- Department of Molecular and Cellular Biology, College of Biological Sciences, University of California, Davis, CA, USA
| | | | | | | | - Christopher S Fraser
- Department of Molecular and Cellular Biology, College of Biological Sciences, University of California, Davis, CA, USA.
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Hajikarimlou M, Hunt K, Kirby G, Takallou S, Jagadeesan SK, Omidi K, Hooshyar M, Burnside D, Moteshareie H, Babu M, Smith M, Holcik M, Samanfar B, Golshani A. Lithium Chloride Sensitivity in Yeast and Regulation of Translation. Int J Mol Sci 2020; 21:ijms21165730. [PMID: 32785068 PMCID: PMC7461102 DOI: 10.3390/ijms21165730] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2020] [Revised: 08/06/2020] [Accepted: 08/07/2020] [Indexed: 12/18/2022] Open
Abstract
For decades, lithium chloride (LiCl) has been used as a treatment option for those living with bipolar disorder (BD). As a result, many studies have been conducted to examine its mode of action, toxicity, and downstream cellular responses. We know that LiCl is able to affect cell signaling and signaling transduction pathways through protein kinase C and glycogen synthase kinase-3, which are considered to be important in regulating gene expression at the translational level. However, additional downstream effects require further investigation, especially in translation pathway. In yeast, LiCl treatment affects the expression, and thus the activity, of PGM2, a phosphoglucomutase involved in sugar metabolism. Inhibition of PGM2 leads to the accumulation of intermediate metabolites of galactose metabolism causing cell toxicity. However, it is not fully understood how LiCl affects gene expression in this matter. In this study, we identified three genes, NAM7, PUS2, and RPL27B, which increase yeast LiCl sensitivity when deleted. We further demonstrate that NAM7, PUS2, and RPL27B influence translation and exert their activity through the 5′-Untranslated region (5′-UTR) of PGM2 mRNA in yeast.
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Affiliation(s)
- Maryam Hajikarimlou
- Department of Biology and Ottawa Institute of Systems Biology, Carleton University, Ottawa, ON K1S 5B6, Canada; (M.H.); (K.H.); (G.K.); (S.T.); (S.K.J.); (K.O.); (M.H.); (D.B.); (H.M.); (M.S.); (B.S.)
| | - Kathryn Hunt
- Department of Biology and Ottawa Institute of Systems Biology, Carleton University, Ottawa, ON K1S 5B6, Canada; (M.H.); (K.H.); (G.K.); (S.T.); (S.K.J.); (K.O.); (M.H.); (D.B.); (H.M.); (M.S.); (B.S.)
| | - Grace Kirby
- Department of Biology and Ottawa Institute of Systems Biology, Carleton University, Ottawa, ON K1S 5B6, Canada; (M.H.); (K.H.); (G.K.); (S.T.); (S.K.J.); (K.O.); (M.H.); (D.B.); (H.M.); (M.S.); (B.S.)
| | - Sarah Takallou
- Department of Biology and Ottawa Institute of Systems Biology, Carleton University, Ottawa, ON K1S 5B6, Canada; (M.H.); (K.H.); (G.K.); (S.T.); (S.K.J.); (K.O.); (M.H.); (D.B.); (H.M.); (M.S.); (B.S.)
| | - Sasi Kumar Jagadeesan
- Department of Biology and Ottawa Institute of Systems Biology, Carleton University, Ottawa, ON K1S 5B6, Canada; (M.H.); (K.H.); (G.K.); (S.T.); (S.K.J.); (K.O.); (M.H.); (D.B.); (H.M.); (M.S.); (B.S.)
| | - Katayoun Omidi
- Department of Biology and Ottawa Institute of Systems Biology, Carleton University, Ottawa, ON K1S 5B6, Canada; (M.H.); (K.H.); (G.K.); (S.T.); (S.K.J.); (K.O.); (M.H.); (D.B.); (H.M.); (M.S.); (B.S.)
| | - Mohsen Hooshyar
- Department of Biology and Ottawa Institute of Systems Biology, Carleton University, Ottawa, ON K1S 5B6, Canada; (M.H.); (K.H.); (G.K.); (S.T.); (S.K.J.); (K.O.); (M.H.); (D.B.); (H.M.); (M.S.); (B.S.)
| | - Daniel Burnside
- Department of Biology and Ottawa Institute of Systems Biology, Carleton University, Ottawa, ON K1S 5B6, Canada; (M.H.); (K.H.); (G.K.); (S.T.); (S.K.J.); (K.O.); (M.H.); (D.B.); (H.M.); (M.S.); (B.S.)
| | - Houman Moteshareie
- Department of Biology and Ottawa Institute of Systems Biology, Carleton University, Ottawa, ON K1S 5B6, Canada; (M.H.); (K.H.); (G.K.); (S.T.); (S.K.J.); (K.O.); (M.H.); (D.B.); (H.M.); (M.S.); (B.S.)
| | - Mohan Babu
- Department of Biochemistry, Research and Innovation Centre, University of Regina, Regina, SK S4S 0A2, Canada;
| | - Myron Smith
- Department of Biology and Ottawa Institute of Systems Biology, Carleton University, Ottawa, ON K1S 5B6, Canada; (M.H.); (K.H.); (G.K.); (S.T.); (S.K.J.); (K.O.); (M.H.); (D.B.); (H.M.); (M.S.); (B.S.)
| | - Martin Holcik
- Department of Health Sciences, Carleton University, Ottawa, ON K1S 5B6, Canada;
| | - Bahram Samanfar
- Department of Biology and Ottawa Institute of Systems Biology, Carleton University, Ottawa, ON K1S 5B6, Canada; (M.H.); (K.H.); (G.K.); (S.T.); (S.K.J.); (K.O.); (M.H.); (D.B.); (H.M.); (M.S.); (B.S.)
- Agriculture and Agri-Food Canada, Ottawa Research and Development Centre (ORDC), Ottawa, ON K1Y 4X2, Canada
| | - Ashkan Golshani
- Department of Biology and Ottawa Institute of Systems Biology, Carleton University, Ottawa, ON K1S 5B6, Canada; (M.H.); (K.H.); (G.K.); (S.T.); (S.K.J.); (K.O.); (M.H.); (D.B.); (H.M.); (M.S.); (B.S.)
- Correspondence:
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9
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Abstract
RNA-binding proteins are important regulators of RNA metabolism and are of critical importance in all steps of the gene expression cascade. The role of aberrantly expressed RBPs in human disease is an exciting research field and the potential application of RBPs as a therapeutic target or a diagnostic marker represents a fast-growing area of research.Aberrant overexpression of the human RNA-binding protein La has been found in various cancer entities including lung, cervical, head and neck, and chronic myelogenous leukaemia. Cancer-associated La protein supports tumour-promoting processes such as proliferation, mobility, invasiveness and tumour growth. Moreover, the La protein maintains the survival of cancer cells by supporting an anti-apoptotic state that may cause resistance to chemotherapeutic therapy.The human La protein represents a multifunctional post-translationally modified RNA-binding protein with RNA chaperone activity that promotes processing of non-coding precursor RNAs but also stimulates the translation of selective messenger RNAs encoding tumour-promoting and anti-apoptotic factors. In our model, La facilitates the expression of those factors and helps cancer cells to cope with cellular stress. In contrast to oncogenes, able to initiate tumorigenesis, we postulate that the aberrantly elevated expression of the human La protein contributes to the non-oncogenic addiction of cancer cells. In this review, we summarize the current understanding about the implications of the RNA-binding protein La in cancer progression and therapeutic resistance. The concept of exploiting the RBP La as a cancer drug target will be discussed.
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Affiliation(s)
- Gunhild Sommer
- Department for Pediatric Hematology, Oncology and Stem Cell Transplantation, University Hospital Regensburg, Regensburg, Germany
| | - Tilman Heise
- Department for Pediatric Hematology, Oncology and Stem Cell Transplantation, University Hospital Regensburg, Regensburg, Germany
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10
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General and Target-Specific DExD/H RNA Helicases in Eukaryotic Translation Initiation. Int J Mol Sci 2020; 21:ijms21124402. [PMID: 32575790 PMCID: PMC7352612 DOI: 10.3390/ijms21124402] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Revised: 06/17/2020] [Accepted: 06/18/2020] [Indexed: 12/19/2022] Open
Abstract
DExD (DDX)- and DExH (DHX)-box RNA helicases, named after their Asp-Glu-x-Asp/His motifs, are integral to almost all RNA metabolic processes in eukaryotic cells. They play myriad roles in processes ranging from transcription and mRNA-protein complex remodeling, to RNA decay and translation. This last facet, translation, is an intricate process that involves DDX/DHX helicases and presents a regulatory node that is highly targetable. Studies aimed at better understanding this family of conserved proteins have revealed insights into their structures, catalytic mechanisms, and biological roles. They have also led to the development of chemical modulators that seek to exploit their essential roles in diseases. Herein, we review the most recent insights on several general and target-specific DDX/DHX helicases in eukaryotic translation initiation.
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Poncová K, Wagner S, Jansen ME, Beznosková P, Gunišová S, Herrmannová A, Zeman J, Dong J, Valášek LS. uS3/Rps3 controls fidelity of translation termination and programmed stop codon readthrough in co-operation with eIF3. Nucleic Acids Res 2020; 47:11326-11343. [PMID: 31642471 PMCID: PMC6868437 DOI: 10.1093/nar/gkz929] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2019] [Revised: 10/03/2019] [Accepted: 10/07/2019] [Indexed: 12/27/2022] Open
Abstract
Ribosome was long considered as a critical yet passive player in protein synthesis. Only recently the role of its basic components, ribosomal RNAs and proteins, in translational control has begun to emerge. Here we examined function of the small ribosomal protein uS3/Rps3, earlier shown to interact with eukaryotic translation initiation factor eIF3, in termination. We identified two residues in consecutive helices occurring in the mRNA entry pore, whose mutations to the opposite charge either reduced (K108E) or increased (R116D) stop codon readthrough. Whereas the latter increased overall levels of eIF3-containing terminating ribosomes in heavy polysomes in vivo indicating slower termination rates, the former specifically reduced eIF3 amounts in termination complexes. Combining these two mutations with the readthrough-reducing mutations at the extreme C-terminus of the a/Tif32 subunit of eIF3 either suppressed (R116D) or exacerbated (K108E) the readthrough phenotypes, and partially corrected or exacerbated the defects in the composition of termination complexes. In addition, we found that K108 affects efficiency of termination in the termination context-specific manner by promoting incorporation of readthrough-inducing tRNAs. Together with the multiple binding sites that we identified between these two proteins, we suggest that Rps3 and eIF3 closely co-operate to control translation termination and stop codon readthrough.
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Affiliation(s)
- Kristýna Poncová
- Laboratory of Regulation of Gene Expression, Institute of Microbiology of the Czech Academy of Sciences, Videnska 1083, 142 20 Prague, the Czech Republic.,Charles University, Faculty of Science, Prague, the Czech Republic
| | - Susan Wagner
- Laboratory of Regulation of Gene Expression, Institute of Microbiology of the Czech Academy of Sciences, Videnska 1083, 142 20 Prague, the Czech Republic
| | - Myrte Esmeralda Jansen
- Laboratory of Regulation of Gene Expression, Institute of Microbiology of the Czech Academy of Sciences, Videnska 1083, 142 20 Prague, the Czech Republic
| | - Petra Beznosková
- Laboratory of Regulation of Gene Expression, Institute of Microbiology of the Czech Academy of Sciences, Videnska 1083, 142 20 Prague, the Czech Republic
| | - Stanislava Gunišová
- Laboratory of Regulation of Gene Expression, Institute of Microbiology of the Czech Academy of Sciences, Videnska 1083, 142 20 Prague, the Czech Republic
| | - Anna Herrmannová
- Laboratory of Regulation of Gene Expression, Institute of Microbiology of the Czech Academy of Sciences, Videnska 1083, 142 20 Prague, the Czech Republic
| | - Jakub Zeman
- Laboratory of Regulation of Gene Expression, Institute of Microbiology of the Czech Academy of Sciences, Videnska 1083, 142 20 Prague, the Czech Republic
| | - Jinsheng Dong
- Laboratory of Gene Regulation and Development, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
| | - Leoš Shivaya Valášek
- Laboratory of Regulation of Gene Expression, Institute of Microbiology of the Czech Academy of Sciences, Videnska 1083, 142 20 Prague, the Czech Republic
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12
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Brumwell A, Fell L, Obress L, Uniacke J. Hypoxia influences polysome distribution of human ribosomal protein S12 and alternative splicing of ribosomal protein mRNAs. RNA (NEW YORK, N.Y.) 2020; 26:361-371. [PMID: 31911497 PMCID: PMC7025504 DOI: 10.1261/rna.070318.119] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/08/2019] [Accepted: 01/02/2020] [Indexed: 06/10/2023]
Abstract
Ribosomes were once considered static in their composition because of their essential role in protein synthesis and kingdom-wide conservation. The existence of tolerated mutations in select ribosomal proteins (RPs), such as in Diamond-Blackfan anemia, is evidence that not all ribosome components are essential. Heterogeneity in the protein composition of eukaryotic ribosomes is an emerging concept with evidence that different pools of ribosomes exist with transcript-specificity. Here, we show that the polysome association of ribosomal proteins is altered by low oxygen (hypoxia), a feature of the tumor microenvironment, in human cells. We quantified ribosomal protein abundance in actively translating polysomes of normoxic and hypoxic HEK293 cells by tandem mass tags mass spectrometry. Our data suggest that RPS12 (eS12) is enriched in hypoxic monosomes, which increases the heavy polysome association of structured transcripts APAF-1 and XIAP. Furthermore, hypoxia induced five alternative splicing events within a subset of RP mRNAs in cell lines. One of these events in RPS24 (eS24 protein) alters the coding sequence to produce two protein isoforms that can incorporate into ribosomes. This splicing event is greatly induced in spheroids and correlates with tumor hypoxia in human prostate cancer. Our data suggest that hypoxia may influence the composition of the human ribosome through changes in RP incorporation and the production of hypoxia-specific RP isoforms.
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Affiliation(s)
- Andrea Brumwell
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario N1G 2W1, Canada
| | - Leslie Fell
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario N1G 2W1, Canada
| | - Lindsay Obress
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario N1G 2W1, Canada
| | - James Uniacke
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario N1G 2W1, Canada
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13
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Raabe K, Honys D, Michailidis C. The role of eukaryotic initiation factor 3 in plant translation regulation. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2019; 145:75-83. [PMID: 31665669 DOI: 10.1016/j.plaphy.2019.10.015] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Revised: 10/07/2019] [Accepted: 10/14/2019] [Indexed: 06/10/2023]
Abstract
Regulation of translation represents a critical step in the regulation of gene expression. In plants, the translation regulation plays an important role at all stages of development and, during stress responses, functions as a fast and flexible tool which not only modulates the global translation rate but also controls the production of specific proteins. Regulation of translation is mostly focused on the initiation phase. There, one of essential initiation factors is the large multisubunit protein complex of eukaryotic translation initiation factor 3 (eIF3). In all eukaryotes, the general eIF3 function is to scaffold the formation of the translation initiation complex and to enhance the accuracy of scanning mechanism for start codon selection. Over the past decades, additional eIF3 functions were described as necessary for development in various eukaryotic organisms, including plants. The importance of the eIF3 complex lies not only at the global level of initiation event, but also in the precise translation regulation of specific transcripts. This review gathers the available information on functions of the plant eIF3 complex.
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Affiliation(s)
- Karel Raabe
- Institute of Experimental Botany, The Czech Academy of Sciences, Rozvojová 263, 165 02, Praha 6, Czech Republic
| | - David Honys
- Institute of Experimental Botany, The Czech Academy of Sciences, Rozvojová 263, 165 02, Praha 6, Czech Republic
| | - Christos Michailidis
- Institute of Experimental Botany, The Czech Academy of Sciences, Rozvojová 263, 165 02, Praha 6, Czech Republic.
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14
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Johnson AG, Petrov AN, Fuchs G, Majzoub K, Grosely R, Choi J, Puglisi JD. Fluorescently-tagged human eIF3 for single-molecule spectroscopy. Nucleic Acids Res 2019; 46:e8. [PMID: 29136179 PMCID: PMC5778468 DOI: 10.1093/nar/gkx1050] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2017] [Accepted: 10/24/2017] [Indexed: 01/09/2023] Open
Abstract
Human translation initiation relies on the combined activities of numerous ribosome-associated eukaryotic initiation factors (eIFs). The largest factor, eIF3, is an ∼800 kDa multiprotein complex that orchestrates a network of interactions with the small 40S ribosomal subunit, other eIFs, and mRNA, while participating in nearly every step of initiation. How these interactions take place during the time course of translation initiation remains unclear. Here, we describe a method for the expression and affinity purification of a fluorescently-tagged eIF3 from human cells. The tagged eIF3 dodecamer is structurally intact, functions in cell-based assays, and interacts with the HCV IRES mRNA and the 40S-IRES complex in vitro. By tracking the binding of single eIF3 molecules to the HCV IRES RNA with a zero-mode waveguides-based instrument, we show that eIF3 samples both wild-type IRES and an IRES that lacks the eIF3-binding region, and that the high-affinity eIF3-IRES interaction is largely determined by slow dissociation kinetics. The application of single-molecule methods to more complex systems involving eIF3 may unveil dynamics underlying mRNA selection and ribosome loading during human translation initiation.
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Affiliation(s)
- Alex G Johnson
- Department of Chemical and Systems Biology, Stanford University, Stanford, CA 94305, USA.,Department of Structural Biology, Stanford University, Stanford, CA 94305, USA
| | - Alexey N Petrov
- Department of Biological Sciences, Auburn University, Auburn, AL 36849, USA
| | - Gabriele Fuchs
- The RNA Institute, Department of Biological Sciences, University of Albany, Albany, NY 12222, USA
| | - Karim Majzoub
- Department of Microbiology and Immunology, Stanford University, Stanford, CA 94305, USA
| | - Rosslyn Grosely
- Department of Structural Biology, Stanford University, Stanford, CA 94305, USA
| | - Junhong Choi
- Department of Structural Biology, Stanford University, Stanford, CA 94305, USA
| | - Joseph D Puglisi
- Department of Structural Biology, Stanford University, Stanford, CA 94305, USA
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15
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Major structural rearrangements of the canonical eukaryotic translation initiation complex. Curr Opin Struct Biol 2018; 53:151-158. [DOI: 10.1016/j.sbi.2018.08.006] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2018] [Accepted: 08/28/2018] [Indexed: 12/24/2022]
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16
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Zydowicz-Machtel P, Swiatkowska A, Popenda Ł, Gorska A, Ciesiołka J. Variants of the 5'-terminal region of p53 mRNA influence the ribosomal scanning and translation efficiency. Sci Rep 2018; 8:1533. [PMID: 29367734 PMCID: PMC5784139 DOI: 10.1038/s41598-018-20010-2] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2017] [Accepted: 01/11/2018] [Indexed: 12/25/2022] Open
Abstract
The p53 protein is one of the major cell cycle regulators. The protein is expressed as at least twelve protein isoforms resulting from the use of alternative promoters, alternative splicing or downstream initiation codons. Importantly, there is growing evidence that translation initiation of p53 mRNA may be regulated by the structure and length of the naturally occurring variants of the 5′-terminal region of p53 mRNA transcripts. Here, several mRNA constructs were synthesized with variable length of the p53 5′-terminal regions and encoding luciferase reporter protein, and their translation was monitored continuously in situ in a rabbit reticulocyte lysate system. Moreover, four additional mRNA constructs were prepared. In two constructs, the structural context of AUG1 initiation codon was altered while in the other two constructs, characteristic hairpin motifs present in the p53 5′-terminal region were changed. Translation of the last two constructs was also performed in the presence of the cap analogue to test the function of the 5′-terminal region in cap-independent translation initiation. Superposition of several structural factors connected with the length of the 5′-terminal region, stable elements of the secondary structure, structural environment of the initiation codon and IRES elements greatly influenced the ribosomal scanning and translation efficiency.
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Affiliation(s)
- Paulina Zydowicz-Machtel
- Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14, 61-704, Poznan, Poland
| | - Agata Swiatkowska
- Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14, 61-704, Poznan, Poland
| | - Łukasz Popenda
- NanoBioMedical Centre, Adam Mickiewicz University in Poznan, Umultowska 85, 61-614, Poznan, Poland
| | - Agnieszka Gorska
- Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14, 61-704, Poznan, Poland
| | - Jerzy Ciesiołka
- Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14, 61-704, Poznan, Poland.
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17
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Valášek LS, Zeman J, Wagner S, Beznosková P, Pavlíková Z, Mohammad MP, Hronová V, Herrmannová A, Hashem Y, Gunišová S. Embraced by eIF3: structural and functional insights into the roles of eIF3 across the translation cycle. Nucleic Acids Res 2017; 45:10948-10968. [PMID: 28981723 PMCID: PMC5737393 DOI: 10.1093/nar/gkx805] [Citation(s) in RCA: 84] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2017] [Accepted: 08/31/2017] [Indexed: 12/31/2022] Open
Abstract
Protein synthesis is mediated via numerous molecules including the ribosome, mRNA, tRNAs, as well as translation initiation, elongation and release factors. Some of these factors play several roles throughout the entire process to ensure proper assembly of the preinitiation complex on the right mRNA, accurate selection of the initiation codon, errorless production of the encoded polypeptide and its proper termination. Perhaps, the most intriguing of these multitasking factors is the eukaryotic initiation factor eIF3. Recent evidence strongly suggests that this factor, which coordinates the progress of most of the initiation steps, does not come off the initiation complex upon subunit joining, but instead it remains bound to 80S ribosomes and gradually falls off during the first few elongation cycles to: (1) promote resumption of scanning on the same mRNA molecule for reinitiation downstream—in case of translation of upstream ORFs short enough to preserve eIF3 bound; or (2) come back during termination on long ORFs to fine tune its fidelity or, if signaled, promote programmed stop codon readthrough. Here, we unite recent structural views of the eIF3–40S complex and discus all known eIF3 roles to provide a broad picture of the eIF3’s impact on translational control in eukaryotic cells.
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Affiliation(s)
- Leoš Shivaya Valášek
- Laboratory of Regulation of Gene Expression, Institute of Microbiology ASCR, Videnska 1083, Prague 142 20, the Czech Republic
| | - Jakub Zeman
- Laboratory of Regulation of Gene Expression, Institute of Microbiology ASCR, Videnska 1083, Prague 142 20, the Czech Republic
| | - Susan Wagner
- Laboratory of Regulation of Gene Expression, Institute of Microbiology ASCR, Videnska 1083, Prague 142 20, the Czech Republic
| | - Petra Beznosková
- Laboratory of Regulation of Gene Expression, Institute of Microbiology ASCR, Videnska 1083, Prague 142 20, the Czech Republic
| | - Zuzana Pavlíková
- Laboratory of Regulation of Gene Expression, Institute of Microbiology ASCR, Videnska 1083, Prague 142 20, the Czech Republic
| | - Mahabub Pasha Mohammad
- Laboratory of Regulation of Gene Expression, Institute of Microbiology ASCR, Videnska 1083, Prague 142 20, the Czech Republic
| | - Vladislava Hronová
- Laboratory of Regulation of Gene Expression, Institute of Microbiology ASCR, Videnska 1083, Prague 142 20, the Czech Republic
| | - Anna Herrmannová
- Laboratory of Regulation of Gene Expression, Institute of Microbiology ASCR, Videnska 1083, Prague 142 20, the Czech Republic
| | - Yaser Hashem
- CNRS, Architecture et Réactivité de l'ARN UPR9002, Université de Strasbourg, 67084 Strasbourg, France
| | - Stanislava Gunišová
- Laboratory of Regulation of Gene Expression, Institute of Microbiology ASCR, Videnska 1083, Prague 142 20, the Czech Republic
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18
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Abstract
The eukaryotic initiation factor 3 (eIF3) is one of the most complex translation initiation factors in mammalian cells, consisting of several subunits (eIF3a to eIF3m). It is crucial in translation initiation and termination, and in ribosomal recycling. Accordingly, deregulated eIF3 expression is associated with different pathological conditions, including cancer. In this manuscript, we discuss the interactome and function of each subunit of the human eIF3 complex. Furthermore, we review how altered levels of eIF3 subunits correlate with neurodegenerative disorders and cancer onset and development; in addition, we evaluate how such misregulation may also trigger infection cascades. A deep understanding of the molecular mechanisms underlying eIF3 role in human disease is essential to develop new eIF3-targeted therapeutic approaches and thus, overcome such conditions.
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Affiliation(s)
- Andreia Gomes-Duarte
- a Department of Human Genetics , Instituto Nacional de Saúde Doutor Ricardo Jorge , Lisbon , Portugal.,b Gene Expression and Regulation Group, Biosystems & Integrative Sciences Institute (BioISI), Faculdade de Ciências , Universidade de Lisboa , Lisbon , Portugal
| | - Rafaela Lacerda
- a Department of Human Genetics , Instituto Nacional de Saúde Doutor Ricardo Jorge , Lisbon , Portugal.,b Gene Expression and Regulation Group, Biosystems & Integrative Sciences Institute (BioISI), Faculdade de Ciências , Universidade de Lisboa , Lisbon , Portugal
| | - Juliane Menezes
- a Department of Human Genetics , Instituto Nacional de Saúde Doutor Ricardo Jorge , Lisbon , Portugal.,b Gene Expression and Regulation Group, Biosystems & Integrative Sciences Institute (BioISI), Faculdade de Ciências , Universidade de Lisboa , Lisbon , Portugal
| | - Luísa Romão
- a Department of Human Genetics , Instituto Nacional de Saúde Doutor Ricardo Jorge , Lisbon , Portugal.,b Gene Expression and Regulation Group, Biosystems & Integrative Sciences Institute (BioISI), Faculdade de Ciências , Universidade de Lisboa , Lisbon , Portugal
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