1
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Zhuravskaya A, Yap K, Hamid F, Makeyev EV. Alternative splicing coupled to nonsense-mediated decay coordinates downregulation of non-neuronal genes in developing mouse neurons. Genome Biol 2024; 25:162. [PMID: 38902825 PMCID: PMC11188260 DOI: 10.1186/s13059-024-03305-8] [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: 07/08/2023] [Accepted: 06/07/2024] [Indexed: 06/22/2024] Open
Abstract
BACKGROUND The functional coupling between alternative pre-mRNA splicing (AS) and the mRNA quality control mechanism called nonsense-mediated decay (NMD) can modulate transcript abundance. Previous studies have identified several examples of such a regulation in developing neurons. However, the systems-level effects of AS-NMD in this context are poorly understood. RESULTS We developed an R package, factR2, which offers a comprehensive suite of AS-NMD analysis functions. Using this tool, we conducted a longitudinal analysis of gene expression in pluripotent stem cells undergoing induced neuronal differentiation. Our analysis uncovers hundreds of AS-NMD events with significant potential to regulate gene expression. Notably, this regulation is significantly overrepresented in specific functional groups of developmentally downregulated genes. Particularly strong association with gene downregulation is detected for alternative cassette exons stimulating NMD upon their inclusion into mature mRNA. By combining bioinformatic analyses with CRISPR/Cas9 genome editing and other experimental approaches we show that NMD-stimulating cassette exons regulated by the RNA-binding protein PTBP1 dampen the expression of their genes in developing neurons. We also provided evidence that the inclusion of NMD-stimulating cassette exons into mature mRNAs is temporally coordinated with NMD-independent gene repression mechanisms. CONCLUSIONS Our study provides an accessible workflow for the discovery and prioritization of AS-NMD targets. It further argues that the AS-NMD pathway plays a widespread role in developing neurons by facilitating the downregulation of functionally related non-neuronal genes.
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Affiliation(s)
- Anna Zhuravskaya
- Centre for Developmental Neurobiology, King's College London, London, SE1 1UL, UK
| | - Karen Yap
- Centre for Developmental Neurobiology, King's College London, London, SE1 1UL, UK
| | - Fursham Hamid
- Centre for Developmental Neurobiology, King's College London, London, SE1 1UL, UK.
| | - Eugene V Makeyev
- Centre for Developmental Neurobiology, King's College London, London, SE1 1UL, UK.
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2
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Henke-Schulz L, Minocha R, Maier NH, Sträßer K. The Prp19C/NTC subunit Syf2 and the Prp19C/NTC-associated protein Cwc15 function in TREX occupancy and transcription elongation. RNA (NEW YORK, N.Y.) 2024; 30:854-865. [PMID: 38627018 PMCID: PMC11182008 DOI: 10.1261/rna.079944.124] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/2024] [Accepted: 04/02/2024] [Indexed: 06/19/2024]
Abstract
The Prp19 complex (Prp19C), also named NineTeen Complex (NTC), is conserved from yeast to human and functions in many different processes such as genome stability, splicing, and transcription elongation. In the latter, Prp19C ensures TREX occupancy at transcribed genes. TREX, in turn, couples transcription to nuclear mRNA export by recruiting the mRNA exporter to transcribed genes and consequently to nascent mRNAs. Here, we assess the function of the nonessential Prp19C subunit Syf2 and the nonessential Prp19C-associated protein Cwc15 in the interaction of Prp19C and TREX with the transcription machinery, Prp19C and TREX occupancy, and transcription elongation. Whereas both proteins are important for Prp19C-TREX interaction, Syf2 is needed for full Prp19C occupancy, and Cwc15 is important for the interaction of Prp19C with RNA polymerase II and TREX occupancy. These partially overlapping functions are corroborated by a genetic interaction between Δcwc15 and Δsyf2 Finally, Cwc15 also interacts genetically with the transcription elongation factor Dst1 and functions in transcription elongation. In summary, we uncover novel roles of the Prp19C component Syf2 and the Prp19C-associated protein Cwc15 in Prp19C's function in transcription elongation.
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Affiliation(s)
- Laura Henke-Schulz
- Institute of Biochemistry, FB08, Justus Liebig University, 35392 Giessen, Germany
| | - Rashmi Minocha
- Institute of Biochemistry, FB08, Justus Liebig University, 35392 Giessen, Germany
| | - Nils Holger Maier
- Institute of Biochemistry, FB08, Justus Liebig University, 35392 Giessen, Germany
| | - Katja Sträßer
- Institute of Biochemistry, FB08, Justus Liebig University, 35392 Giessen, Germany
- Cardio-Pulmonary Institute (CPI), EXC 2026, 35392 Giessen, Germany
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3
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Bensaude O, Barbosa I, Morillo L, Dikstein R, Le Hir H. Exon-junction complex association with stalled ribosomes and slow translation-independent disassembly. Nat Commun 2024; 15:4209. [PMID: 38760352 PMCID: PMC11101648 DOI: 10.1038/s41467-024-48371-5] [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: 08/05/2023] [Accepted: 04/29/2024] [Indexed: 05/19/2024] Open
Abstract
Exon junction complexes are deposited at exon-exon junctions during splicing. They are primarily known to activate non-sense mediated degradation of transcripts harbouring premature stop codons before the last intron. According to a popular model, exon-junction complexes accompany mRNAs to the cytoplasm where the first translating ribosome pushes them out. However, they are also removed by uncharacterized, translation-independent mechanisms. Little is known about kinetic and transcript specificity of these processes. Here we tag core subunits of exon-junction complexes with complementary split nanoluciferase fragments to obtain sensitive and quantitative assays for complex formation. Unexpectedly, exon-junction complexes form large stable mRNPs containing stalled ribosomes. Complex assembly and disassembly rates are determined after an arrest in transcription and/or translation. 85% of newly deposited exon-junction complexes are disassembled by a translation-dependent mechanism. However as this process is much faster than the translation-independent one, only 30% of the exon-junction complexes present in cells at steady state require translation for disassembly. Deep RNA sequencing shows a bias of exon-junction complex bound transcripts towards microtubule and centrosome coding ones and demonstrate that the lifetimes of exon-junction complexes are transcript-specific. This study provides a dynamic vision of exon-junction complexes and uncovers their unexpected stable association with ribosomes.
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Affiliation(s)
- Olivier Bensaude
- Institut de Biologie de l'Ecole Normale Supérieure (IBENS), Ecole Normale Supérieure, CNRS, INSERM, PSL Research University, Paris, France.
| | - Isabelle Barbosa
- Institut de Biologie de l'Ecole Normale Supérieure (IBENS), Ecole Normale Supérieure, CNRS, INSERM, PSL Research University, Paris, France
| | - Lucia Morillo
- Institut de Biologie de l'Ecole Normale Supérieure (IBENS), Ecole Normale Supérieure, CNRS, INSERM, PSL Research University, Paris, France
| | - Rivka Dikstein
- Department of Biomolecular Sciences, The Weizmann Institute of Science, Rehovot, Israel
| | - Hervé Le Hir
- Institut de Biologie de l'Ecole Normale Supérieure (IBENS), Ecole Normale Supérieure, CNRS, INSERM, PSL Research University, Paris, France.
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4
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Han X, Xing L, Hong Y, Zhang X, Hao B, Lu JY, Huang M, Wang Z, Ma S, Zhan G, Li T, Hao X, Tao Y, Li G, Zhou S, Zheng Z, Shao W, Zeng Y, Ma D, Zhang W, Xie Z, Deng H, Yan J, Deng W, Shen X. Nuclear RNA homeostasis promotes systems-level coordination of cell fate and senescence. Cell Stem Cell 2024; 31:694-716.e11. [PMID: 38631356 DOI: 10.1016/j.stem.2024.03.015] [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: 09/22/2023] [Revised: 02/01/2024] [Accepted: 03/26/2024] [Indexed: 04/19/2024]
Abstract
Understanding cellular coordination remains a challenge despite knowledge of individual pathways. The RNA exosome, targeting a wide range of RNA substrates, is often downregulated in cellular senescence. Utilizing an auxin-inducible system, we observed that RNA exosome depletion in embryonic stem cells significantly affects the transcriptome and proteome, causing pluripotency loss and pre-senescence onset. Mechanistically, exosome depletion triggers acute nuclear RNA aggregation, disrupting nuclear RNA-protein equilibrium. This disturbance limits nuclear protein availability and hinders polymerase initiation and engagement, reducing gene transcription. Concurrently, it promptly disrupts nucleolar transcription, ribosomal processes, and nuclear exporting, resulting in a translational shutdown. Prolonged exosome depletion induces nuclear structural changes resembling senescent cells, including aberrant chromatin compaction, chromocenter disassembly, and intensified heterochromatic foci. These effects suggest that the dynamic turnover of nuclear RNA orchestrates crosstalk between essential processes to optimize cellular function. Disruptions in nuclear RNA homeostasis result in systemic functional decline, altering the cell state and promoting senescence.
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Affiliation(s)
- Xue Han
- State Key Laboratory of Membrane Biology, Beijing Frontier Research Center for Biological Structure, Tsinghua-Peking Joint Center for Life Sciences, School of Basic Medical Sciences, Tsinghua University, Beijing 100084, China
| | - Linqing Xing
- State Key Laboratory of Membrane Biology, Beijing Frontier Research Center for Biological Structure, Tsinghua-Peking Joint Center for Life Sciences, School of Basic Medical Sciences, Tsinghua University, Beijing 100084, China
| | - Yantao Hong
- State Key Laboratory of Membrane Biology, Beijing Frontier Research Center for Biological Structure, Tsinghua-Peking Joint Center for Life Sciences, School of Basic Medical Sciences, Tsinghua University, Beijing 100084, China
| | - Xuechun Zhang
- State Key Laboratory of Membrane Biology, Beijing Frontier Research Center for Biological Structure, Tsinghua-Peking Joint Center for Life Sciences, School of Basic Medical Sciences, Tsinghua University, Beijing 100084, China
| | - Bo Hao
- SXMU-Tsinghua Collaborative Innovation Center for Frontier Medicine, Shanxi Medical University, Taiyuan, Shanxi 030001, China
| | - J Yuyang Lu
- State Key Laboratory of Membrane Biology, Beijing Frontier Research Center for Biological Structure, Tsinghua-Peking Joint Center for Life Sciences, School of Basic Medical Sciences, Tsinghua University, Beijing 100084, China
| | - Mengyuan Huang
- State Key Laboratory of Membrane Biology, Beijing Frontier Research Center for Biological Structure, Tsinghua-Peking Joint Center for Life Sciences, School of Basic Medical Sciences, Tsinghua University, Beijing 100084, China
| | - Zuhui Wang
- Biomedical Pioneering Innovation Center (BIOPIC), Beijing Advanced Innovation Center for Genomics (ICG), Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871, China
| | - Shaoqian Ma
- State Key Laboratory of Membrane Biology, Beijing Frontier Research Center for Biological Structure, Tsinghua-Peking Joint Center for Life Sciences, School of Basic Medical Sciences, Tsinghua University, Beijing 100084, China
| | - Ge Zhan
- State Key Laboratory of Membrane Biology, Beijing Frontier Research Center for Biological Structure, Tsinghua-Peking Joint Center for Life Sciences, School of Basic Medical Sciences, Tsinghua University, Beijing 100084, China
| | - Tong Li
- State Key Laboratory of Membrane Biology, Beijing Frontier Research Center for Biological Structure, Tsinghua-Peking Joint Center for Life Sciences, School of Basic Medical Sciences, Tsinghua University, Beijing 100084, China
| | - Xiaowen Hao
- State Key Laboratory of Membrane Biology, Beijing Frontier Research Center for Biological Structure, Tsinghua-Peking Joint Center for Life Sciences, School of Basic Medical Sciences, Tsinghua University, Beijing 100084, China
| | - Yibing Tao
- State Key Laboratory of Membrane Biology, Beijing Frontier Research Center for Biological Structure, Tsinghua-Peking Joint Center for Life Sciences, School of Basic Medical Sciences, Tsinghua University, Beijing 100084, China
| | - Guanwen Li
- State Key Laboratory of Membrane Biology, Beijing Frontier Research Center for Biological Structure, Tsinghua-Peking Joint Center for Life Sciences, School of Basic Medical Sciences, Tsinghua University, Beijing 100084, China
| | - Shuqin Zhou
- State Key Laboratory of Membrane Biology, Beijing Frontier Research Center for Biological Structure, Tsinghua-Peking Joint Center for Life Sciences, School of Basic Medical Sciences, Tsinghua University, Beijing 100084, China
| | - Zheng Zheng
- State Key Laboratory of Membrane Biology, Beijing Frontier Research Center for Biological Structure, Tsinghua-Peking Joint Center for Life Sciences, School of Basic Medical Sciences, Tsinghua University, Beijing 100084, China
| | - Wen Shao
- State Key Laboratory of Membrane Biology, Beijing Frontier Research Center for Biological Structure, Tsinghua-Peking Joint Center for Life Sciences, School of Basic Medical Sciences, Tsinghua University, Beijing 100084, China
| | - Yitian Zeng
- State Key Laboratory of Membrane Biology, Beijing Frontier Research Center for Biological Structure, Tsinghua-Peking Joint Center for Life Sciences, School of Basic Medical Sciences, Tsinghua University, Beijing 100084, China
| | - Dacheng Ma
- MOE Key Laboratory of Bioinformatics and Bioinformatics Division, Center for Synthetic and Systems Biology, Department of Automation, Beijing National Research Center for Information Science and Technology, Tsinghua University, Beijing 100084, China
| | - Wenhao Zhang
- MOE Key Laboratory of Bioinformatics, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Zhen Xie
- MOE Key Laboratory of Bioinformatics and Bioinformatics Division, Center for Synthetic and Systems Biology, Department of Automation, Beijing National Research Center for Information Science and Technology, Tsinghua University, Beijing 100084, China
| | - Haiteng Deng
- MOE Key Laboratory of Bioinformatics, School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Jiangwei Yan
- SXMU-Tsinghua Collaborative Innovation Center for Frontier Medicine, Shanxi Medical University, Taiyuan, Shanxi 030001, China
| | - Wulan Deng
- Biomedical Pioneering Innovation Center (BIOPIC), Beijing Advanced Innovation Center for Genomics (ICG), Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871, China
| | - Xiaohua Shen
- State Key Laboratory of Membrane Biology, Beijing Frontier Research Center for Biological Structure, Tsinghua-Peking Joint Center for Life Sciences, School of Basic Medical Sciences, Tsinghua University, Beijing 100084, China; SXMU-Tsinghua Collaborative Innovation Center for Frontier Medicine, Shanxi Medical University, Taiyuan, Shanxi 030001, China.
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5
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Petrauskas A, Fortunati DL, Kandi AR, Pothapragada SS, Agrawal K, Singh A, Huelsmeier J, Hillebrand J, Brown G, Chaturvedi D, Lee J, Lim C, Auburger G, VijayRaghavan K, Ramaswami M, Bakthavachalu B. Structured and disordered regions of Ataxin-2 contribute differently to the specificity and efficiency of mRNP granule formation. PLoS Genet 2024; 20:e1011251. [PMID: 38768217 PMCID: PMC11166328 DOI: 10.1371/journal.pgen.1011251] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2024] [Revised: 06/11/2024] [Accepted: 04/05/2024] [Indexed: 05/22/2024] Open
Abstract
Ataxin-2 (ATXN2) is a gene implicated in spinocerebellar ataxia type II (SCA2), amyotrophic lateral sclerosis (ALS) and Parkinsonism. The encoded protein is a therapeutic target for ALS and related conditions. ATXN2 (or Atx2 in insects) can function in translational activation, translational repression, mRNA stability and in the assembly of mRNP-granules, a process mediated by intrinsically disordered regions (IDRs). Previous work has shown that the LSm (Like-Sm) domain of Atx2, which can help stimulate mRNA translation, antagonizes mRNP-granule assembly. Here we advance these findings through a series of experiments on Drosophila and human Ataxin-2 proteins. Results of Targets of RNA Binding Proteins Identified by Editing (TRIBE), co-localization and immunoprecipitation experiments indicate that a polyA-binding protein (PABP) interacting, PAM2 motif of Ataxin-2 may be a major determinant of the mRNA and protein content of Ataxin-2 mRNP granules. Experiments with transgenic Drosophila indicate that while the Atx2-LSm domain may protect against neurodegeneration, structured PAM2- and unstructured IDR- interactions both support Atx2-induced cytotoxicity. Taken together, the data lead to a proposal for how Ataxin-2 interactions are remodelled during translational control and how structured and non-structured interactions contribute differently to the specificity and efficiency of RNP granule condensation as well as to neurodegeneration.
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Affiliation(s)
- Arnas Petrauskas
- Trinity College Institute of Neuroscience, School of Genetics and Microbiology, Smurfit Institute of Genetics and School of Natural Sciences, Trinity College Dublin, Dublin, Ireland
| | - Daniel L. Fortunati
- Trinity College Institute of Neuroscience, School of Genetics and Microbiology, Smurfit Institute of Genetics and School of Natural Sciences, Trinity College Dublin, Dublin, Ireland
| | - Arvind Reddy Kandi
- School of Biosciences and Bioengineering, Indian Institute of Technology, Mandi, India
| | | | - Khushboo Agrawal
- Tata Institute for Genetics and Society Centre at inStem, Bellary Road, Bangalore, India
- School of Biotechnology, Amrita Vishwa Vidyapeetham University, Kollam, Kerala, India
| | - Amanjot Singh
- National Centre for Biological Sciences, TIFR, Bangalore, India
- Manipal Institute of Regenerative Medicine, MAHE-Bengaluru, Govindapura, Bengaluru, India
| | - Joern Huelsmeier
- Trinity College Institute of Neuroscience, School of Genetics and Microbiology, Smurfit Institute of Genetics and School of Natural Sciences, Trinity College Dublin, Dublin, Ireland
| | - Jens Hillebrand
- Trinity College Institute of Neuroscience, School of Genetics and Microbiology, Smurfit Institute of Genetics and School of Natural Sciences, Trinity College Dublin, Dublin, Ireland
| | - Georgia Brown
- Trinity College Institute of Neuroscience, School of Genetics and Microbiology, Smurfit Institute of Genetics and School of Natural Sciences, Trinity College Dublin, Dublin, Ireland
| | | | - Jongbo Lee
- Department of Biological Sciences, Ulsan National Institute of Science and Technology (UNIST), 50 UNIST-gil, Ulsan, Republic of Korea
| | - Chunghun Lim
- Department of Biological Sciences, Ulsan National Institute of Science and Technology (UNIST), 50 UNIST-gil, Ulsan, Republic of Korea
| | - Georg Auburger
- Experimental Neurology, Medical School, Goethe University, Frankfurt, Germany
| | | | - Mani Ramaswami
- Trinity College Institute of Neuroscience, School of Genetics and Microbiology, Smurfit Institute of Genetics and School of Natural Sciences, Trinity College Dublin, Dublin, Ireland
- National Centre for Biological Sciences, TIFR, Bangalore, India
| | - Baskar Bakthavachalu
- School of Biosciences and Bioengineering, Indian Institute of Technology, Mandi, India
- Tata Institute for Genetics and Society Centre at inStem, Bellary Road, Bangalore, India
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6
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Puig-Segui MS, Decker CJ, Barlit H, Labunskyy VM, Parker R, Puig S. Regulation of translation in response to iron deficiency in human cells. Sci Rep 2024; 14:8451. [PMID: 38605136 PMCID: PMC11009288 DOI: 10.1038/s41598-024-59003-9] [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: 01/08/2024] [Accepted: 04/05/2024] [Indexed: 04/13/2024] Open
Abstract
Protein synthesis is a highly energy-consuming process that is downregulated in response to many environmental stresses or adverse conditions. Studies in the yeast Saccharomyces cerevisiae have shown that bulk translation is inhibited during adaptation to iron deficiency, which is consistent with its requirement for ribosome biogenesis and recycling. Although iron deficiency anemia is the most common human nutritional disorder, how iron modulates translation in mammals is poorly understood. Studies during erythropoiesis have shown that iron bioavailability is coordinated with globin synthesis via bulk translation regulation. However, little is known about the control of translation during iron limitation in other tissues. Here, we investigated how iron depletion affects protein synthesis in human osteosarcoma U-2 OS cells. By adding an extracellular iron chelator, we observed that iron deficiency limits cell proliferation, induces autophagy, and decreases the global rate of protein synthesis. Analysis of specific molecular markers indicates that the inhibition of bulk translation upon iron limitation occurs through the eukaryotic initiation factor eIF2α and mechanistic target of rapamycin (mTOR) pathways. In contrast to other environmental and nutritional stresses, iron depletion does not trigger the assembly of messenger ribonucleoprotein stress granules, which typically form upon polysome disassembly.
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Affiliation(s)
- Mireia S Puig-Segui
- Department of Biochemistry, University of Colorado Boulder, Boulder, CO, USA
- Escuela Técnica Superior de Ingeniería Agronómica y del Medio Natural (ETSIAMN), Universidad Politécnica de Valencia (UPV), Valencia, Spain
| | - Carolyn J Decker
- Department of Biochemistry, University of Colorado Boulder, Boulder, CO, USA
- Howard Hughes Medical Institute, University of Colorado Boulder, Boulder, CO, USA
| | - Hanna Barlit
- Department of Dermatology, Boston University School of Medicine, Boston, MA, 02118, USA
| | | | - Roy Parker
- Department of Biochemistry, University of Colorado Boulder, Boulder, CO, USA
- Howard Hughes Medical Institute, University of Colorado Boulder, Boulder, CO, USA
- BioFrontiers Institute, University of Colorado Boulder, Boulder, CO, USA
| | - Sergi Puig
- Departamento de Biotecnología, Instituto de Agroquímica y Tecnología de Alimentos (IATA), Consejo Superior de Investigaciones Científicas (CSIC), Calle Catedrático Agustín Escardino 7, 46980, Paterna, Valencia, Spain.
- Department of Biochemistry, University of Colorado Boulder, Boulder, CO, USA.
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7
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He PC, He C. mRNA accessibility within mRNPs as a determinant of gene expression. Trends Biochem Sci 2024; 49:199-207. [PMID: 38071089 PMCID: PMC10939938 DOI: 10.1016/j.tibs.2023.11.003] [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: 07/31/2023] [Revised: 11/05/2023] [Accepted: 11/10/2023] [Indexed: 01/31/2024]
Abstract
Gene expression is a complex process requiring many control mechanisms to achieve a desired phenotype. DNA accessibility within chromatin is well established as an important determinant of gene expression. By contrast, while mRNA also associates with a complement of proteins, the exact nature of messenger ribonucleoprotein (mRNP) packaging and its functional relevance is not as clear. Recent reports indicate that exon junction complex (EJC)-mediated mRNP packaging renders exon junction-proximal regions inaccessible for m6A methylation, and that EJCs reside within the inaccessible interior of globular transcription and export (TREX) complex-associated nuclear mRNPs. We propose that 'mRNA accessibility' within mRNPs is an important determinant of gene expression that may modulate the specificity of a broad array of regulatory processes including but not limited to m6A methylation.
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Affiliation(s)
- P Cody He
- Pritzker School of Medicine, The University of Chicago, Chicago, IL 60637, USA
| | - Chuan He
- Department of Chemistry, Department of Biochemistry and Molecular Biology, Institute for Biophysical Dynamics, The University of Chicago, Chicago, IL 60637, USA; Committee on Immunology, The University of Chicago, Chicago, IL 60637, USA; Howard Hughes Medical Institute, The University of Chicago, Chicago, IL 60637, USA.
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8
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Kern C, Radon C, Wende W, Leitner A, Sträßer K. Cross-linking mass spectrometric analysis of the endogenous TREX complex from Saccharomyces cerevisiae. RNA (NEW YORK, N.Y.) 2023; 29:1870-1880. [PMID: 37699651 PMCID: PMC10653388 DOI: 10.1261/rna.079758.123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2023] [Accepted: 08/22/2023] [Indexed: 09/14/2023]
Abstract
The conserved TREX complex has multiple functions in gene expression such as transcription elongation, 3' end processing, mRNP assembly and nuclear mRNA export as well as the maintenance of genomic stability. In Saccharomyces cerevisiae, TREX is composed of the pentameric THO complex, the DEAD-box RNA helicase Sub2, the nuclear mRNA export adaptor Yra1, and the SR-like proteins Gbp2 and Hrb1. Here, we present the structural analysis of the endogenous TREX complex of S. cerevisiae purified from its native environment. To this end, we used cross-linking mass spectrometry to gain structural information on regions of the complex that are not accessible to classical structural biology techniques. We also used negative-stain electron microscopy to investigate the organization of the cross-linked complex used for XL-MS by comparing our endogenous TREX complex with recently published structural models of recombinant THO-Sub2 complexes. According to our analysis, the endogenous yeast TREX complex preferentially assembles into a dimer.
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Affiliation(s)
- Carina Kern
- Institute of Biochemistry, FB08, Justus Liebig University, 35392 Giessen, Germany
| | - Christin Radon
- Institute of Biochemistry and Biology, Department of Biochemistry, University of Potsdam, 14476 Potsdam-Golm, Germany
| | - Wolfgang Wende
- Institute of Biochemistry, FB08, Justus Liebig University, 35392 Giessen, Germany
| | - Alexander Leitner
- Department of Biology, Institute of Molecular Systems Biology, ETH Zurich, 8093 Zurich, Switzerland
| | - Katja Sträßer
- Institute of Biochemistry, FB08, Justus Liebig University, 35392 Giessen, Germany
- Cardio-Pulmonary Institute (CPI), EXC 2026, 35392 Giessen, Germany
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9
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Asada R, Dominguez A, Montpetit B. Single-molecule quantitation of RNA-binding protein occupancy and stoichiometry defines a role for Yra1 (Aly/REF) in nuclear mRNP organization. Cell Rep 2023; 42:113415. [PMID: 37963019 PMCID: PMC10841842 DOI: 10.1016/j.celrep.2023.113415] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2023] [Revised: 10/09/2023] [Accepted: 10/25/2023] [Indexed: 11/16/2023] Open
Abstract
RNA-binding proteins (RBPs) interact with mRNA to form supramolecular complexes called messenger ribonucleoprotein (mRNP) particles. These dynamic assemblies direct and regulate individual steps of gene expression; however, their composition and functional importance remain largely unknown. Here, we develop a total internal reflection fluorescence-based single-molecule imaging assay to investigate stoichiometry and co-occupancy of 15 RBPs within mRNPs from Saccharomyces cerevisiae. We show compositional heterogeneity of single mRNPs and plasticity across different growth conditions, with major co-occupants of mRNPs containing the nuclear cap-binding complex identified as Yra1 (1-10 copies), Nab2 (1-6 copies), and Npl3 (1-6 copies). Multicopy Yra1-bound mRNPs are specifically co-occupied by the THO complex and assembled on mRNAs biased by transcript length and RNA secondary structure. Yra1 depletion results in decreased compaction of nuclear mRNPs demonstrating a packaging function. Together, we provide a quantitative framework for gene- and condition-dependent RBP occupancy and stoichiometry in individual nuclear mRNPs.
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Affiliation(s)
- Ryuta Asada
- Department of Viticulture and Enology, University of California, Davis, Davis, CA 95616, USA
| | - Andrew Dominguez
- Department of Viticulture and Enology, University of California, Davis, Davis, CA 95616, USA; Biochemistry, Molecular, Cellular, and Developmental Biology Graduate Group, University of California, Davis, Davis, CA 95616, USA
| | - Ben Montpetit
- Department of Viticulture and Enology, University of California, Davis, Davis, CA 95616, USA; Biochemistry, Molecular, Cellular, and Developmental Biology Graduate Group, University of California, Davis, Davis, CA 95616, USA.
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10
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Morillo L, Paternina T, Alasseur Q, Genovesio A, Schwartz S, Le Hir H. Comprehensive mapping of exon junction complex binding sites reveals universal EJC deposition in Drosophila. BMC Biol 2023; 21:246. [PMID: 37936138 PMCID: PMC10630996 DOI: 10.1186/s12915-023-01749-1] [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: 08/04/2023] [Accepted: 10/26/2023] [Indexed: 11/09/2023] Open
Abstract
BACKGROUND The exon junction complex (EJC) is involved in most steps of the mRNA life cycle, ranging from splicing to nonsense-mediated mRNA decay (NMD). It is assembled by the splicing machinery onto mRNA in a sequence-independent manner. A fundamental open question is whether the EJC is deposited onto all exon‒exon junctions or only on a subset of them. Several previous studies have made observations supportive of the latter, yet these have been limited by methodological constraints. RESULTS In this study, we sought to overcome these limitations via the integration of two different approaches for transcriptome-wide mapping of EJCs. Our results revealed that nearly all, if not all, internal exons consistently harbor an EJC in Drosophila, demonstrating that EJC presence is an inherent consequence of the splicing reaction. Furthermore, our study underscores the limitations of eCLIP methods in fully elucidating the landscape of RBP binding sites. Our findings highlight how highly specific (low false positive) methodologies can lead to erroneous interpretations due to partial sensitivity (high false negatives). CONCLUSIONS This study contributes to our understanding of EJC deposition and its association with pre-mRNA splicing. The universal presence of EJC on internal exons underscores its significance in ensuring proper mRNA processing. Additionally, our observations highlight the need to consider both specificity and sensitivity in RBP mapping methodologies.
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Affiliation(s)
- Lucía Morillo
- Institut de Biologie de l'École Normale Supérieure (IBENS), École Normale Supérieure, CNRS, INSERM, Université PSL, Paris, 75005, France
| | - Toni Paternina
- Institut de Biologie de l'École Normale Supérieure (IBENS), École Normale Supérieure, CNRS, INSERM, Université PSL, Paris, 75005, France
| | - Quentin Alasseur
- Institut de Biologie de l'École Normale Supérieure (IBENS), École Normale Supérieure, CNRS, INSERM, Université PSL, Paris, 75005, France
| | - Auguste Genovesio
- Institut de Biologie de l'École Normale Supérieure (IBENS), École Normale Supérieure, CNRS, INSERM, Université PSL, Paris, 75005, France
| | - Schraga Schwartz
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, 7630031, Israel
| | - Hervé Le Hir
- Institut de Biologie de l'École Normale Supérieure (IBENS), École Normale Supérieure, CNRS, INSERM, Université PSL, Paris, 75005, France.
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11
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Ripin N, Parker R. Formation, function, and pathology of RNP granules. Cell 2023; 186:4737-4756. [PMID: 37890457 PMCID: PMC10617657 DOI: 10.1016/j.cell.2023.09.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Revised: 07/28/2023] [Accepted: 09/07/2023] [Indexed: 10/29/2023]
Abstract
Ribonucleoprotein (RNP) granules are diverse membrane-less organelles that form through multivalent RNA-RNA, RNA-protein, and protein-protein interactions between RNPs. RNP granules are implicated in many aspects of RNA physiology, but in most cases their functions are poorly understood. RNP granules can be described through four key principles. First, RNP granules often arise because of the large size, high localized concentrations, and multivalent interactions of RNPs. Second, cells regulate RNP granule formation by multiple mechanisms including posttranslational modifications, protein chaperones, and RNA chaperones. Third, RNP granules impact cell physiology in multiple manners. Finally, dysregulation of RNP granules contributes to human diseases. Outstanding issues in the field remain, including determining the scale and molecular mechanisms of RNP granule function and how granule dysfunction contributes to human disease.
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Affiliation(s)
- Nina Ripin
- Department of Biochemistry and Howard Hughes Medical Institute, University of Colorado Boulder, Boulder, CO 80303, USA
| | - Roy Parker
- Department of Biochemistry and Howard Hughes Medical Institute, University of Colorado Boulder, Boulder, CO 80303, USA.
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12
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Cardona AH, Ecsedi S, Khier M, Yi Z, Bahri A, Ouertani A, Valero F, Labrosse M, Rouquet S, Robert S, Loubat A, Adekunle D, Hubstenberger A. Self-demixing of mRNA copies buffers mRNA:mRNA and mRNA:regulator stoichiometries. Cell 2023; 186:4310-4324.e23. [PMID: 37703874 DOI: 10.1016/j.cell.2023.08.018] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Revised: 06/08/2023] [Accepted: 08/16/2023] [Indexed: 09/15/2023]
Abstract
Cellular homeostasis requires the robust control of biomolecule concentrations, but how do millions of mRNAs coordinate their stoichiometries in the face of dynamic translational changes? Here, we identified a two-tiered mechanism controlling mRNA:mRNA and mRNA:protein stoichiometries where mRNAs super-assemble into condensates with buffering capacity and sorting selectivity through phase-transition mechanisms. Using C. elegans oogenesis arrest as a model, we investigated the transcriptome cytosolic reorganization through the sequencing of RNA super-assemblies coupled with single mRNA imaging. Tightly repressed mRNAs self-assembled into same-sequence nanoclusters that further co-assembled into multiphase condensates. mRNA self-sorting was concentration dependent, providing a self-buffering mechanism that is selective to sequence identity and controls mRNA:mRNA stoichiometries. The cooperative sharing of limiting translation repressors between clustered mRNAs prevented the disruption of mRNA:repressor stoichiometries in the cytosol. Robust control of mRNA:mRNA and mRNA:protein stoichiometries emerges from mRNA self-demixing and cooperative super-assembly into multiphase multiscale condensates with dynamic storage capacity.
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Affiliation(s)
| | - Szilvia Ecsedi
- Université Côte D'Azur, CNRS, Inserm, iBV, 06108 Nice, France
| | - Mokrane Khier
- Université Côte D'Azur, CNRS, Inserm, iBV, 06108 Nice, France
| | - Zhou Yi
- Université Côte D'Azur, CNRS, Inserm, iBV, 06108 Nice, France
| | - Alia Bahri
- Université Côte D'Azur, CNRS, Inserm, iBV, 06108 Nice, France
| | - Amira Ouertani
- Université Côte D'Azur, CNRS, Inserm, iBV, 06108 Nice, France
| | - Florian Valero
- Université Côte D'Azur, CNRS, Inserm, iBV, 06108 Nice, France
| | | | - Sami Rouquet
- Université Côte D'Azur, CNRS, Inserm, iBV, 06108 Nice, France
| | - Stéphane Robert
- Université Aix Marseille, Inserm, INRAE, C2VN, 13005 Marseille, France
| | - Agnès Loubat
- Université Côte D'Azur, CNRS, Inserm, iBV, 06108 Nice, France
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13
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Patil SS, Panchal V, Røstbø T, Romanyuk S, Hollås H, Brenk R, Grindheim AK, Vedeler A. RNA-binding is an ancient trait of the Annexin family. Front Cell Dev Biol 2023; 11:1161588. [PMID: 37397259 PMCID: PMC10311354 DOI: 10.3389/fcell.2023.1161588] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2023] [Accepted: 05/25/2023] [Indexed: 07/04/2023] Open
Abstract
Introduction: The regulation of intracellular functions in mammalian cells involves close coordination of cellular processes. During recent years it has become evident that the sorting, trafficking and distribution of transport vesicles and mRNA granules/complexes are closely coordinated to ensure effective simultaneous handling of all components required for a specific function, thereby minimizing the use of cellular energy. Identification of proteins acting at the crossroads of such coordinated transport events will ultimately provide mechanistic details of the processes. Annexins are multifunctional proteins involved in a variety of cellular processes associated with Ca2+-regulation and lipid binding, linked to the operation of both the endocytic and exocytic pathways. Furthermore, certain Annexins have been implicated in the regulation of mRNA transport and translation. Since Annexin A2 binds specific mRNAs via its core structure and is also present in mRNP complexes, we speculated whether direct association with RNA could be a common property of the mammalian Annexin family sharing a highly similar core structure. Methods and results: Therefore, we performed spot blot and UV-crosslinking experiments to assess the mRNA binding abilities of the different Annexins, using annexin A2 and c-myc 3'UTRs as well as c-myc 5'UTR as baits. We supplemented the data with immunoblot detection of selected Annexins in mRNP complexes derived from the neuroendocrine rat PC12 cells. Furthermore, biolayer interferometry was used to determine the KD of selected Annexin-RNA interactions, which indicated distinct affinities. Amongst these Annexins, Annexin A13 and the core structures of Annexin A7, Annexin A11 bind c-myc 3'UTR with KDs in the nanomolar range. Of the selected Annexins, only Annexin A2 binds the c-myc 5'UTR indicating some selectivity. Discussion: The oldest members of the mammalian Annexin family share the ability to associate with RNA, suggesting that RNA-binding is an ancient trait of this protein family. Thus, the combined RNA- and lipid-binding properties of the Annexins make them attractive candidates to participate in coordinated long-distance transport of membrane vesicles and mRNAs regulated by Ca2+. The present screening results can thus pave the way for studies of the multifunctional Annexins in a novel cellular context.
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Affiliation(s)
- Sudarshan S. Patil
- Neurotargeting Group, Department of Biomedicine, University of Bergen, Bergen, Norway
| | - Vipul Panchal
- Biorecognition Unit, Department of Biomedicine, University of Bergen, Bergen, Norway
| | - Trude Røstbø
- Neurotargeting Group, Department of Biomedicine, University of Bergen, Bergen, Norway
| | - Sofya Romanyuk
- Neurotargeting Group, Department of Biomedicine, University of Bergen, Bergen, Norway
| | - Hanne Hollås
- Neurotargeting Group, Department of Biomedicine, University of Bergen, Bergen, Norway
| | - Ruth Brenk
- Biorecognition Unit, Department of Biomedicine, University of Bergen, Bergen, Norway
| | - Ann Kari Grindheim
- Neurotargeting Group, Department of Biomedicine, University of Bergen, Bergen, Norway
| | - Anni Vedeler
- Neurotargeting Group, Department of Biomedicine, University of Bergen, Bergen, Norway
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14
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Hemphill W, Fenske R, Gooding A, Cech T. PRC2 direct transfer from G-quadruplex RNA to dsDNA has implications for RNA-binding chromatin modifiers. Proc Natl Acad Sci U S A 2023; 120:e2220528120. [PMID: 37252986 PMCID: PMC10266057 DOI: 10.1073/pnas.2220528120] [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: 12/02/2022] [Accepted: 05/01/2023] [Indexed: 06/01/2023] Open
Abstract
The chromatin-modifying enzyme, Polycomb Repressive Complex 2 (PRC2), deposits the H3K27me3 epigenetic mark to negatively regulate expression at numerous target genes, and this activity has been implicated in embryonic development, cell differentiation, and various cancers. A biological role for RNA binding in regulating PRC2 histone methyltransferase activity is generally accepted, but the nature and mechanism of this relationship remains an area of active investigation. Notably, many in vitro studies demonstrate that RNA inhibits PRC2 activity on nucleosomes through mutually antagonistic binding, while some in vivo studies indicate that PRC2's RNA-binding activity is critical for facilitating its biological function(s). Here we use biochemical, biophysical, and computational approaches to interrogate PRC2's RNA and DNA-binding kinetics. Our findings demonstrate that PRC2-polynucleotide dissociation rates are dependent on the concentration of free ligand, indicating the potential for direct transfer between nucleic acid ligands without a free-enzyme intermediate. Direct transfer explains the variation in previously reported dissociation kinetics, allows reconciliation of prior in vitro and in vivo studies, and expands the potential mechanisms of RNA-mediated PRC2 regulation. Moreover, simulations indicate that such a direct transfer mechanism could be obligatory for RNA to recruit proteins to chromatin.
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Affiliation(s)
- Wayne O. Hemphill
- Department of Biochemistry, BioFrontiers Institute, University of Colorado Boulder, Boulder, CO80309
- HHMI, University of Colorado Boulder, Boulder, CO80309
| | - Regan Fenske
- Department of Biochemistry, BioFrontiers Institute, University of Colorado Boulder, Boulder, CO80309
- HHMI, University of Colorado Boulder, Boulder, CO80309
| | - Anne R. Gooding
- Department of Biochemistry, BioFrontiers Institute, University of Colorado Boulder, Boulder, CO80309
- HHMI, University of Colorado Boulder, Boulder, CO80309
| | - Thomas R. Cech
- Department of Biochemistry, BioFrontiers Institute, University of Colorado Boulder, Boulder, CO80309
- HHMI, University of Colorado Boulder, Boulder, CO80309
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15
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Becker JT, Auerbach AA, Harris RS. APEX3 - an optimized tool for rapid and unbiased proximity labeling. J Mol Biol 2023; 435:168145. [PMID: 37182813 DOI: 10.1016/j.jmb.2023.168145] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Revised: 05/03/2023] [Accepted: 05/09/2023] [Indexed: 05/16/2023]
Abstract
Macromolecular interactions regulate all aspects of biology. The identification of interacting partners and complexes is important for understanding cellular processes, host-pathogen conflicts, and organismal development. Multiple methods exist to label and enrich interacting proteins in living cells. Notably, the soybean ascorbate peroxidase, APEX2, rapidly biotinylates adjacent biomolecules in the presence of biotin-phenol and hydrogen peroxide. However, during initial experiments with this system, we found that APEX2 exhibits a cytoplasmic-biased localization and is sensitive to the nuclear export inhibitor leptomycin B (LMB). This led us to identify a putative nuclear export signal (NES) at the carboxy-terminus of APEX2 (NESAPEX2), structurally adjacent to the conserved heme binding site. This putative NES is functional as evidenced by cytoplasmic localization and LMB sensitivity of a mCherry-NESAPEX2 chimeric construct. Single amino acid substitutions of multiple hydrophobic residues within NESAPEX2 eliminate cytoplasm-biased localization of both mCherry-NESAPEX2 as well as full-length APEX2. However, all but one of these NES substitutions also compromises peroxide-dependent labeling. This unique separation-of-function mutant, APEX2-L242A, is termed APEX3. Localization and functionality of APEX3 are confirmed by fusion to the nucleocytoplasmic shuttling transcriptional factor, RELA. APEX3 is therefore an optimized tool for unbiased proximity labeling of cellular proteins and interacting factors.
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Affiliation(s)
- Jordan T Becker
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota Twin Cities, Minneapolis, MN, USA 55455; Department of Microbiology and Immunology, University of Minnesota Twin Cities, Minneapolis, MN, USA 55455; Institute for Molecular Virology, University of Minnesota Twin Cities, Minneapolis, MN, USA 55455.
| | - Ashley A Auerbach
- Department of Biochemistry and Structural Biology, University of Texas Health San Antonio, San Antonio, TX, USA 78229
| | - Reuben S Harris
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota Twin Cities, Minneapolis, MN, USA 55455; Department of Biochemistry and Structural Biology, University of Texas Health San Antonio, San Antonio, TX, USA 78229; Howard Hughes Medical Institute, University of Texas Health San Antonio, San Antonio, TX, USA 78229.
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16
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González B, Aldea M, Cullen PJ. Chaperone-Dependent Degradation of Cdc42 Promotes Cell Polarity and Shields the Protein from Aggregation. Mol Cell Biol 2023; 43:200-222. [PMID: 37114947 PMCID: PMC10184603 DOI: 10.1080/10985549.2023.2198171] [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: 11/29/2022] [Revised: 03/02/2023] [Accepted: 03/06/2023] [Indexed: 04/29/2023] Open
Abstract
Rho GTPases are global regulators of cell polarity and signaling. By exploring the turnover regulation of the yeast Rho GTPase Cdc42p, we identified new regulatory features surrounding the stability of the protein. We specifically show that Cdc42p is degraded at 37 °C by chaperones through lysine residues located in the C-terminus of the protein. Cdc42p turnover at 37 °C occurred by the 26S proteasome in an ESCRT-dependent manner in the lysosome/vacuole. By analyzing versions of Cdc42p that were defective for turnover, we show that turnover at 37 °C promoted cell polarity but was defective for sensitivity to mating pheromone, presumably mediated through a Cdc42p-dependent MAP kinase pathway. We also identified one residue (K16) in the P-loop of the protein that was critical for Cdc42p stability. Accumulation of Cdc42pK16R in some contexts led to the formation of protein aggregates, which were enriched in aging mother cells and cells undergoing proteostatic stress. Our study uncovers new aspects of protein turnover regulation of a Rho-type GTPase that may extend to other systems. Moreover, residues identified here that mediate Cdc42p turnover correlate with several human diseases, which may suggest that turnover regulation of Cdc42p is important to aspects of human health.
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Affiliation(s)
- Beatriz González
- Department of Biological Sciences, State University of New York at Buffalo, New York, USA
| | - Martí Aldea
- Molecular Biology Institute of Barcelona (IBMB), CSIC, Barcelona, Spain
| | - Paul J. Cullen
- Department of Biological Sciences, State University of New York at Buffalo, New York, USA
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17
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Pacheco-Fiallos B, Vorländer MK, Riabov-Bassat D, Fin L, O'Reilly FJ, Ayala FI, Schellhaas U, Rappsilber J, Plaschka C. mRNA recognition and packaging by the human transcription-export complex. Nature 2023; 616:828-835. [PMID: 37020021 PMCID: PMC7614608 DOI: 10.1038/s41586-023-05904-0] [Citation(s) in RCA: 22] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2022] [Accepted: 03/01/2023] [Indexed: 04/07/2023]
Abstract
Newly made mRNAs are processed and packaged into mature ribonucleoprotein complexes (mRNPs) and are recognized by the essential transcription-export complex (TREX) for nuclear export1,2. However, the mechanisms of mRNP recognition and three-dimensional mRNP organization are poorly understood3. Here we report cryo-electron microscopy and tomography structures of reconstituted and endogenous human mRNPs bound to the 2-MDa TREX complex. We show that mRNPs are recognized through multivalent interactions between the TREX subunit ALYREF and mRNP-bound exon junction complexes. Exon junction complexes can multimerize through ALYREF, which suggests a mechanism for mRNP organization. Endogenous mRNPs form compact globules that are coated by multiple TREX complexes. These results reveal how TREX may simultaneously recognize, compact and protect mRNAs to promote their packaging for nuclear export. The organization of mRNP globules provides a framework to understand how mRNP architecture facilitates mRNA biogenesis and export.
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Affiliation(s)
- Belén Pacheco-Fiallos
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC), Vienna, Austria
- Vienna BioCenter, Doctoral School of the University of Vienna and Medical University of Vienna, Vienna, Austria
| | - Matthias K Vorländer
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC), Vienna, Austria
| | - Daria Riabov-Bassat
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC), Vienna, Austria
| | - Laura Fin
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC), Vienna, Austria
| | - Francis J O'Reilly
- Bioanalytics Unit, Institute of Biotechnology, Technische Universität Berlin, Berlin, Germany
| | - Farja I Ayala
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC), Vienna, Austria
- Vienna BioCenter, Doctoral School of the University of Vienna and Medical University of Vienna, Vienna, Austria
| | - Ulla Schellhaas
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC), Vienna, Austria
- Vienna BioCenter, Doctoral School of the University of Vienna and Medical University of Vienna, Vienna, Austria
| | - Juri Rappsilber
- Bioanalytics Unit, Institute of Biotechnology, Technische Universität Berlin, Berlin, Germany
- Wellcome Centre for Cell Biology, University of Edinburgh, Edinburgh, UK
| | - Clemens Plaschka
- Research Institute of Molecular Pathology (IMP), Vienna BioCenter (VBC), Vienna, Austria.
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18
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von der Haar T, Mulroney TE, Hedayioglu F, Kurusamy S, Rust M, Lilley KS, Thaventhiran JE, Willis AE, Smales CM. Translation of in vitro-transcribed RNA therapeutics. Front Mol Biosci 2023; 10:1128067. [PMID: 36845540 PMCID: PMC9943971 DOI: 10.3389/fmolb.2023.1128067] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Accepted: 01/30/2023] [Indexed: 02/10/2023] Open
Abstract
In vitro transcribed, modified messenger RNAs (IVTmRNAs) have been used to vaccinate billions of individuals against the SARS-CoV-2 virus, and are currently being developed for many additional therapeutic applications. IVTmRNAs must be translated into proteins with therapeutic activity by the same cellular machinery that also translates native endogenous transcripts. However, different genesis pathways and routes of entry into target cells as well as the presence of modified nucleotides mean that the way in which IVTmRNAs engage with the translational machinery, and the efficiency with which they are being translated, differs from native mRNAs. This review summarises our current knowledge of commonalities and differences in translation between IVTmRNAs and cellular mRNAs, which is key for the development of future design strategies that can generate IVTmRNAs with improved activity in therapeutic applications.
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Affiliation(s)
- Tobias von der Haar
- School of Biosciences, Division of Natural Sciences, University of Kent, Canterbury, United Kingdom
| | - Thomas E. Mulroney
- MRC Toxicology Unit, Gleeson Building, University of Cambridge, Cambridge, United Kingdom
| | - Fabio Hedayioglu
- School of Biosciences, Division of Natural Sciences, University of Kent, Canterbury, United Kingdom
| | - Sathishkumar Kurusamy
- School of Biosciences, Division of Natural Sciences, University of Kent, Canterbury, United Kingdom
| | - Maria Rust
- MRC Toxicology Unit, Gleeson Building, University of Cambridge, Cambridge, United Kingdom
| | - Kathryn S. Lilley
- Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom
| | - James E. Thaventhiran
- MRC Toxicology Unit, Gleeson Building, University of Cambridge, Cambridge, United Kingdom
| | - Anne E. Willis
- MRC Toxicology Unit, Gleeson Building, University of Cambridge, Cambridge, United Kingdom
| | - C. Mark Smales
- School of Biosciences, Division of Natural Sciences, University of Kent, Canterbury, United Kingdom
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19
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Keil P, Wulf A, Kachariya N, Reuscher S, Hühn K, Silbern I, Altmüller J, Keller M, Stehle R, Zarnack K, Sattler M, Urlaub H, Sträßer K. Npl3 functions in mRNP assembly by recruitment of mRNP components to the transcription site and their transfer onto the mRNA. Nucleic Acids Res 2022; 51:831-851. [PMID: 36583366 PMCID: PMC9881175 DOI: 10.1093/nar/gkac1206] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2022] [Revised: 11/25/2022] [Accepted: 12/07/2022] [Indexed: 12/31/2022] Open
Abstract
RNA-binding proteins (RBPs) control every RNA metabolic process by multiple protein-RNA and protein-protein interactions. Their roles have largely been analyzed by crude mutations, which abrogate multiple functions at once and likely impact the structural integrity of the large ribonucleoprotein particles (RNPs) these proteins function in. Using UV-induced RNA-protein crosslinking of entire cells, protein complex purification and mass spectrometric analysis, we identified >100 in vivo RNA crosslinks in 16 nuclear mRNP components in Saccharomyces cerevisiae. For functional analysis, we chose Npl3, which displayed crosslinks in its two RNA recognition motifs (RRMs) and in the connecting flexible linker region. Both RRM domains and the linker uniquely contribute to RNA recognition as revealed by NMR and structural analyses. Interestingly, mutations in these regions cause different phenotypes, indicating distinct functions of the different RNA-binding domains. Notably, an npl3-Linker mutation strongly impairs recruitment of several mRNP components to chromatin and incorporation of other mRNP components into nuclear mRNPs, establishing a so far unknown function of Npl3 in nuclear mRNP assembly. Taken together, our integrative analysis uncovers a specific function of the RNA-binding activity of the nuclear mRNP component Npl3. This approach can be readily applied to RBPs in any RNA metabolic process.
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Affiliation(s)
| | | | | | - Samira Reuscher
- Buchmann Institute for Molecular Life Sciences (BMLS) & Institute of Molecular Biosciences, Goethe University Frankfurt, Max-von-Laue-Strasse 15, 60438 Frankfurt a.M., Germany
| | - Kristin Hühn
- Institute of Biochemistry, FB08, Justus Liebig University Giessen, Heinrich-Buff-Ring 17, 35392 Giessen, Germany
| | - Ivan Silbern
- Max Planck Institute for Multidisciplinary Sciences, Am Fassberg 11, 37077 Goettingen, University Medical Center Goettingen, Institute of Clinical Chemistry, Robert-Koch-Strasse 40, 37075 Goettingen, Germany
| | - Janine Altmüller
- Cologne Center for Genomics (CCG), University of Cologne, Weyertal 115b, 50931 Cologne, Germany,Technology platform genomics, Berlin Institute of Health at Charité - Universitätsmedizin Berlin and Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany
| | - Mario Keller
- Buchmann Institute for Molecular Life Sciences (BMLS) & Institute of Molecular Biosciences, Goethe University Frankfurt, Max-von-Laue-Strasse 15, 60438 Frankfurt a.M., Germany
| | - Ralf Stehle
- Bavarian NMR Center (BNMRZ), Department of Bioscience, School of Natural Sciences, Technical University of Munich, Lichtenbergstrasse 4, 85748 Garching, Germany,Institute of Structural Biology, Helmholtz Center Munich, Ingolstaedter Landstrasse 1, 85764 Neuherberg, Germany
| | - Kathi Zarnack
- Buchmann Institute for Molecular Life Sciences (BMLS) & Institute of Molecular Biosciences, Goethe University Frankfurt, Max-von-Laue-Strasse 15, 60438 Frankfurt a.M., Germany,Cardio-Pulmonary Institute (CPI), EXC 2026, 35392 Giessen, Germany
| | | | | | - Katja Sträßer
- To whom correspondence should be addressed. Tel: +49 641 99 35400; Fax: +49 641 99 35409;
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20
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Burke JM, Ripin N, Ferretti MB, St Clair LA, Worden-Sapper ER, Salgado F, Sawyer SL, Perera R, Lynch KW, Parker R. RNase L activation in the cytoplasm induces aberrant processing of mRNAs in the nucleus. PLoS Pathog 2022; 18:e1010930. [PMID: 36318584 PMCID: PMC9651596 DOI: 10.1371/journal.ppat.1010930] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2022] [Revised: 11/11/2022] [Accepted: 10/17/2022] [Indexed: 11/13/2022] Open
Abstract
The antiviral endoribonuclease, RNase L, is activated by the mammalian innate immune response to destroy host and viral RNA to ultimately reduce viral gene expression. Herein, we show that RNase L and RNase L-mediated mRNA decay are primarily localized to the cytoplasm. Consequently, RNA-binding proteins (RBPs) translocate from the cytoplasm to the nucleus upon RNase L activation due to the presence of intact nuclear RNA. The re-localization of RBPs to the nucleus coincides with global alterations to RNA processing in the nucleus. While affecting many host mRNAs, these alterations are pronounced in mRNAs encoding type I and type III interferons and correlate with their retention in the nucleus and reduction in interferon protein production. Similar RNA processing defects also occur during infection with either dengue virus or SARS-CoV-2 when RNase L is activated. These findings reveal that the distribution of RBPs between the nucleus and cytosol is dictated by the availability of RNA in each compartment. Thus, viral infections that trigger RNase L-mediated cytoplasmic RNA in the cytoplasm also alter RNA processing in the nucleus, resulting in an ingenious multi-step immune block to protein biogenesis.
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Affiliation(s)
- James M. Burke
- Department of Biochemistry, University of Colorado Boulder, Boulder, Colorado, United States of America
- Department of Molecular Medicine, University of Florida Scripps Biomedical Research, Jupiter, Florida, United States of America
| | - Nina Ripin
- Department of Biochemistry, University of Colorado Boulder, Boulder, Colorado, United States of America
- Howard Hughes Medical Institute, University of Colorado Boulder, Boulder, Colorado, United States of America
| | - Max B. Ferretti
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Laura A. St Clair
- Center for Vector-Borne Infectious Diseases, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado, United States of America
- Center for Metabolism of Infectious Diseases, Colorado State University, Fort Collins, Colorado, United States of America
| | - Emma R. Worden-Sapper
- Department of Molecular, Cellular and Developmental Biology, University of Colorado Boulder, Boulder, Colorado, United States of America
| | - Fernando Salgado
- Department of Molecular Medicine, University of Florida Scripps Biomedical Research, Jupiter, Florida, United States of America
| | - Sara L. Sawyer
- Department of Molecular, Cellular and Developmental Biology, University of Colorado Boulder, Boulder, Colorado, United States of America
| | - Rushika Perera
- Center for Vector-Borne Infectious Diseases, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado, United States of America
- Center for Metabolism of Infectious Diseases, Colorado State University, Fort Collins, Colorado, United States of America
| | - Kristen W. Lynch
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America
| | - Roy Parker
- Department of Biochemistry, University of Colorado Boulder, Boulder, Colorado, United States of America
- Howard Hughes Medical Institute, University of Colorado Boulder, Boulder, Colorado, United States of America
- BioFrontiers Institute, University of Colorado Boulder, Boulder, Colorado, United States of America
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21
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Guo T, Modi OL, Hirano J, Guzman HV, Tsuboi T. Single-chain models illustrate the 3D RNA folding shape during translation. BIOPHYSICAL REPORTS 2022; 2:100065. [PMID: 36425329 PMCID: PMC9680788 DOI: 10.1016/j.bpr.2022.100065] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Accepted: 07/19/2022] [Indexed: 06/16/2023]
Abstract
The three-dimensional conformation of RNA is important in the function and fate of the molecule. The common conformation of mRNA is formed based on the closed-loop structure and internal base pairings with the activity of the ribosome movements. However, recent reports suggest that the closed-loop structure might not be formed in many mRNAs. This implies that mRNA can be considered as a single polymer in the cell. Here, we introduce the Three-dimensional RNA Illustration Program (TRIP) to model the three-dimensional RNA folding shape based on single-chain models and angle restriction of each bead component from previously reported single-molecule fluorescence in situ hybridization (smFISH) experimental data. This simulation method was able to recapitulate the mRNA conformation change of the translation activity and three-dimensional positional interaction between an organelle and its localized mRNAs as end-to-end distances. Within the analyzed cases, base-pairing interactions only have minor effects on the three-dimensional mRNA conformation, and instead single-chain polymer characteristics have a more significant impact on the conformation. This top-down method will be used to interpret the aggregation mechanism of mRNA under different cellular conditions such as nucleolus and phase-separated granules.
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Affiliation(s)
- Tianze Guo
- Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, California
| | - Olivia L. Modi
- Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, California
| | - Jillian Hirano
- Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, California
| | - Horacio V. Guzman
- Department of Theoretical Physics, Jozef Stefan Institute, Ljubljana, Slovenia
| | - Tatsuhisa Tsuboi
- Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, California
- Institute of Biopharmaceutical and Health Engineering, Tsinghua Shenzhen International Graduate School, Shenzhen, Guangdong, China
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22
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Post-Transcriptional Control of mRNA Metabolism and Protein Secretion: The Third Level of Regulation within the NF-κB System. Biomedicines 2022; 10:biomedicines10092108. [PMID: 36140209 PMCID: PMC9495616 DOI: 10.3390/biomedicines10092108] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Revised: 08/12/2022] [Accepted: 08/21/2022] [Indexed: 11/17/2022] Open
Abstract
The NF-κB system is a key transcriptional pathway that regulates innate and adaptive immunity because it triggers the activation and differentiation processes of lymphocytes and myeloid cells during immune responses. In most instances, binding to cytoplasmic inhibitory IκB proteins sequesters NF-κB into an inactive state, while a plethora of external triggers activate three complex signaling cascades that mediate the release and nuclear translocation of the NF-κB DNA-binding subunits. In addition to these cytosolic steps (level 1 of NF-κB regulation), NF-κB activity is also controlled in the nucleus by signaling events, cofactors and the chromatin environment to precisely determine chromatin recruitment and the specificity and timing of target gene transcription (level 2 of NF-κB regulation). Here, we discuss an additional layer of the NF-κB system that manifests in various steps of post-transcriptional gene expression and protein secretion. This less-studied regulatory level allows reduction of (transcriptional) noise and signal integration and endows time-shifted control of the secretion of inflammatory mediators. Detailed knowledge of these steps is important, as dysregulated post-transcriptional NF-κB signaling circuits are likely to foster chronic inflammation and contribute to the formation and maintenance of a tumor-promoting microenvironment.
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23
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Çetin B, O’Leary SE. mRNA- and factor-driven dynamic variability controls eIF4F-cap recognition for translation initiation. Nucleic Acids Res 2022; 50:8240-8261. [PMID: 35871304 PMCID: PMC9371892 DOI: 10.1093/nar/gkac631] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Revised: 06/29/2022] [Accepted: 07/20/2022] [Indexed: 11/29/2022] Open
Abstract
mRNA 5′ cap recognition by eIF4F is a key element of eukaryotic translational control. Kinetic differences in eIF4F–mRNA interactions have long been proposed to mediate translation-efficiency differences between mRNAs, and recent transcriptome-wide studies have revealed significant heterogeneity in eIF4F engagement with differentially-translated mRNAs. However, detailed kinetic information exists only for eIF4F interactions with short model RNAs. We developed and applied single-molecule fluorescence approaches to directly observe real-time Saccharomyces cerevisiae eIF4F subunit interactions with full-length polyadenylated mRNAs. We found that eIF4E–mRNA association rates linearly anticorrelate with mRNA length. eIF4G–mRNA interaction accelerates eIF4E–mRNA association in proportion to mRNA length, as does an eIF4F-independent activity of eIF4A, though cap-proximal secondary structure still plays an important role in defining the final association rates. eIF4F–mRNA interactions remained dominated by effects of eIF4G, but were modulated to different extents for different mRNAs by the presence of eIF4A and ATP. We also found that eIF4A-catalyzed ATP hydrolysis ejects eIF4E, and likely eIF4E•eIF4G from the mRNA after initial eIF4F•mRNA complex formation, suggesting a mechanism to prepare the mRNA 5′ end for ribosome recruitment. Our results support a role for mRNA-specific, factor-driven eIF4F association rates in kinetically controlling translation.
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Affiliation(s)
- Burak Çetin
- Graduate Program in Cell, Molecular, and Developmental Biology, University of California Riverside , Riverside, CA 92521, USA
| | - Seán E O’Leary
- Graduate Program in Cell, Molecular, and Developmental Biology, University of California Riverside , Riverside, CA 92521, USA
- Department of Biochemistry, University of California Riverside , Riverside, CA 92521, USA
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24
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A conserved domain of Drosophila RNA-binding protein Pumilio interacts with multiple CCR4-NOT deadenylase complex subunits to repress target mRNAs. J Biol Chem 2022; 298:102270. [PMID: 35850301 PMCID: PMC9418443 DOI: 10.1016/j.jbc.2022.102270] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2022] [Revised: 07/06/2022] [Accepted: 07/07/2022] [Indexed: 11/20/2022] Open
Abstract
Pumilio is a sequence-specific RNA-binding protein that controls development, stem cell fate, and neurological functions in Drosophila. Pumilio represses protein expression by destabilizing target mRNAs in a manner dependent on the CCR4-NOT deadenylase complex. Three unique repression domains in the N-terminal region of Pumilio were previously shown to recruit CCR4-NOT, but how they do so was not well understood. In this study, we identified the motifs that are necessary and sufficient for the activity of the third repression domain of Pumilio, designated RD3, which is present in all isoforms and has conserved regulatory function. We identified multiple conserved regions of RD3 that are important for repression activity in cell-based reporter gene assays. Using yeast two hybrid assays, we show that RD3 contacts specific regions of the Not1, Not2, and Not3 subunits of the CCR4-NOT complex. Our results indicate that RD3 makes multivalent interactions with CCR4-NOT mediated by conserved short linear interaction motifs. Specifically, two phenylalanine residues in RD3 make crucial contacts with Not1 that are essential for its repression activity. Using reporter gene assays, we also identify three new target mRNAs that are repressed by Pumilio and show that RD3 contributes to their regulation. Together, these results provide important insights into the mechanism by which Pumilio recruits CCR4-NOT to regulate the expression of target mRNAs.
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25
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Bishola Tshitenge T, Reichert L, Liu B, Clayton C. Several different sequences are implicated in bloodstream-form-specific gene expression in Trypanosoma brucei. PLoS Negl Trop Dis 2022; 16:e0010030. [PMID: 35312693 PMCID: PMC8982893 DOI: 10.1371/journal.pntd.0010030] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Revised: 04/05/2022] [Accepted: 03/03/2022] [Indexed: 12/30/2022] Open
Abstract
The parasite Trypanosoma brucei grows as bloodstream forms in mammalian hosts, and as procyclic forms in tsetse flies. In trypanosomes, gene expression regulation depends heavily on post-transcriptional mechanisms. Both the RNA-binding protein RBP10 and glycosomal phosphoglycerate kinase PGKC are expressed only in mammalian-infective forms. RBP10 targets procyclic-specific mRNAs for destruction, while PGKC is required for bloodstream-form glycolysis. Developmental regulation of both is essential: expression of either RBP10 or PGKC in procyclic forms inhibits their proliferation. We show that the 3’-untranslated region of the RBP10 mRNA is extraordinarily long—7.3kb—and were able to identify six different sequences, scattered across the untranslated region, which can independently cause bloodstream-form-specific expression. The 3’-untranslated region of the PGKC mRNA, although much shorter, still contains two different regions, of 125 and 153nt, that independently gave developmental regulation. No short consensus sequences were identified that were enriched either within these regulatory regions, or when compared with other mRNAs with similar regulation, suggesting that more than one regulatory RNA-binding protein is important for repression of mRNAs in procyclic forms. We also identified regions, including an AU repeat, that increased expression in bloodstream forms, or suppressed it in both forms. Trypanosome mRNAs that encode RNA-binding proteins often have extremely extended 3’-untranslated regions. We suggest that one function of this might be to act as a fail-safe mechanism to ensure correct regulation even if mRNA processing or expression of trans regulators is defective. The parasite Trypanosoma brucei causes sleeping sickness in humans, and nagana in cattle, and is transmitted by Tsetse flies. It grows in the bloodstream and tissue fluids of mammalian hosts, as "bloodstream forms", and as "procyclic forms" in the midgut of tsetse flies. Several hundred proteins are expressed in a stage-specific fashion, and this is essential for parasite survival in the different environments. RBP10 is an RNA-binding protein that is expressed only in bloodstream forms. It binds to procyclic-specific mRNAs, and causes their destruction. PGKC is an enzyme that is also specifically expressed in bloodstream forms. Developmental regulation of both is essential: expression of either RBP10 or PGKC in procyclic forms prevents their growth. The mRNAs encoding both proteins are very unstable in procyclic forms, and the sequences responsible are in an "untranslated region" of the mRNA—sequences that follow the part that codes for protein. We here show that the mRNA encoding PGKC has two regions that independently cause developmental regulation, and that the very long untranslated region of the RBP10 mRNA has no fewer than six regulatory regions, but there were no obvious similarities between them. We suggest that the presence of several different regulatory sequences in trypanosome mRNAs might be a fail-safe mechanism to ensure correct regulation.
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Affiliation(s)
| | - Lena Reichert
- Heidelberg University Center for Molecular Biology (ZMBH), Heidelberg, Germany
| | - Bin Liu
- Heidelberg University Center for Molecular Biology (ZMBH), Heidelberg, Germany
| | - Christine Clayton
- Heidelberg University Center for Molecular Biology (ZMBH), Heidelberg, Germany
- * E-mail:
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26
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Weis K, Hondele M. The Role of DEAD-Box ATPases in Gene Expression and the Regulation of RNA-Protein Condensates. Annu Rev Biochem 2022; 91:197-219. [PMID: 35303788 DOI: 10.1146/annurev-biochem-032620-105429] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
DEAD-box ATPases constitute a very large protein family present in all cells, often in great abundance. From bacteria to humans, they play critical roles in many aspects of RNA metabolism, and due to their widespread importance in RNA biology, they have been characterized in great detail at both the structural and biochemical levels. DEAD-box proteins function as RNA-dependent ATPases that can unwind short duplexes of RNA, remodel ribonucleoprotein (RNP) complexes, or act as clamps to promote RNP assembly. Yet, it often remains enigmatic how individual DEAD-box proteins mechanistically contribute to specific RNA-processing steps. Here, we review the role of DEAD-box ATPases in the regulation of gene expression and propose that one common function of these enzymes is in the regulation of liquid-liquid phase separation of RNP condensates. Expected final online publication date for the Annual Review of Biochemistry, Volume 91 is June 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
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Affiliation(s)
- Karsten Weis
- Institute of Biochemistry, Department of Biology, ETH Zurich, Zurich, Switzerland;
| | - Maria Hondele
- Biozentrum, University of Basel, Basel, Switzerland;
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27
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Zhang H, He C, Guo X, Fang Y, Lai Q, Wang X, Pan X, Li H, Qin K, Li A, Liu S, Li Q. DDX39B contributes to the proliferation of colorectal cancer through direct binding to CDK6/CCND1. Cell Death Dis 2022; 8:30. [PMID: 35046400 PMCID: PMC8770491 DOI: 10.1038/s41420-022-00827-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2021] [Revised: 12/01/2021] [Accepted: 01/04/2022] [Indexed: 12/12/2022]
Abstract
DDX39B (also called UAP56 or BAT1) which is a kind of DEAD-box family helicase plays pivotal roles in mRNA binding, splicing, and export. It has been found upregulated in many kinds of tumors as an oncogene. Nevertheless, the underlying molecular mechanisms of DDX39B in the proliferation of human colorectal cancer (CRC) remain fairly elusive. In our study, function experiments including the CCK8 and colony formation assay revealed that DDX39B facilitates CRC proliferation in vitro. DDX39B knockdown cells were administered for the orthotopic CRC tumor xenograft mouse model, after which tumor growth was monitored and immunohistochemistry (IHC) was performed to prove that DDX39B can also facilitates CRC proliferation in vivo. Flow cytometry demonstrated that DDX39B promotes the proliferation of CRC cells by driving the cell cycle from G0/G1 phase to the S phase. Mechanistically, RNA-binding protein immunoprecipitation-sequencing (RIP-seq) confirmed that DDX39B binds directly to the first exon of the CDK6/CCND1 pre-mRNA and upregulates their expression. Splicing experiments in vitro using a RT-PCR and gel electrophoresis assay confirmed that DDX39B promotes CDK6/CCND1 pre-mRNA splicing. Rescue experiments indicated that CDK6/CCND1 is a downstream effector of DDX39B-mediated CRC cell proliferation. Collectively, our results demonstrated that DDX39B and CDK6/CCND1 direct interactions serve as a CRC proliferation promoter, which can accelerate the G1/S phase transition to enhance CRC proliferation, and can offer novel and emerging treatment strategies targeting this cell proliferation-promoting gene.
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28
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Ripin N, Parker R. Are stress granules the RNA analogs of misfolded protein aggregates? RNA (NEW YORK, N.Y.) 2022; 28:67-75. [PMID: 34670846 PMCID: PMC8675284 DOI: 10.1261/rna.079000.121] [Citation(s) in RCA: 28] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Ribonucleoprotein granules are ubiquitous features of eukaryotic cells. Several observations argue that the formation of at least some RNP granules can be considered analogous to the formation of unfolded protein aggregates. First, unfolded protein aggregates form from the exposure of promiscuous protein interaction surfaces, while some mRNP granules form, at least in part, by promiscuous intermolecular RNA-RNA interactions due to exposed RNA surfaces when mRNAs are not engaged with ribosomes. Second, analogous to the role of protein chaperones in preventing misfolded protein aggregation, cells contain abundant "RNA chaperones" to limit inappropriate RNA-RNA interactions and prevent mRNP granule formation. Third, analogous to the role of protein aggregates in diseases, situations where RNA aggregation exceeds the capacity of RNA chaperones to disaggregate RNAs may contribute to human disease. Understanding that RNP granules can be considered as promiscuous, reversible RNA aggregation events allow insight into their composition and how cells have evolved functions for RNP granules.
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Affiliation(s)
- Nina Ripin
- Department of Biochemistry and Howard Hughes Medical Institute, University of Colorado Boulder, Boulder, Colorado 80303, USA
| | - Roy Parker
- Department of Biochemistry and Howard Hughes Medical Institute, University of Colorado Boulder, Boulder, Colorado 80303, USA
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29
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Filippelli RL, Omer A, Li S, van Oostende-Triplet C, Gallouzi IE, Chang NC. Automated Quantification of Subcellular Particles in Myogenic Progenitors. Curr Protoc 2021; 1:e325. [PMID: 34879178 DOI: 10.1002/cpz1.325] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Fluorescence microscopy is a powerful tool enabling the visualization of protein localization within cells. In this article, we outline an automated and non-biased way to detect and quantify subcellular particles using immunocytochemistry, fluorescence microscopy, and the program CellProfiler. We discuss the examination of two types of subcellular particles: messenger ribonucleoprotein (mRNP) granules, namely processing bodies and stress granules, and autophagosomes. Fluorescent microscopy Z-stacks are acquired and deconvolved, and maximum intensity images are generated. The number of subcellular particles per cell is then quantified using the described CellProfiler pipeline. We also explain how to isolate primary myoblast progenitor cells from mice, which were used to obtain the presented results. Last, we discuss the critical parameters to be considered for each of these techniques. Both mRNP granules and autophagosomes play important roles in sequestering intracellular cargo, such as messenger RNAs and RNA-binding proteins for mRNP granules and cytoplasmic waste for autophagosomes. The methods outlined in this article are widely applicable for studies relating to subcellular particle formation, localization, and flux during homeostasis, following stimuli, and during disease. © 2021 The Authors. Current Protocols published by Wiley Periodicals LLC. Basic Protocol 1: Immunofluorescence microscopy of messenger ribonucleoprotein granules in primary myoblasts Alternate Protocol: Immunofluorescence microscopy of autophagosomes in primary myoblasts Support Protocol: Isolation of primary myoblasts from mice Basic Protocol 2: Automated quantification of subcellular particles.
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Affiliation(s)
| | - Amr Omer
- Department of Biochemistry, McGill University, Montréal, Québec, Canada
| | - Shulei Li
- Department of Biochemistry, McGill University, Montréal, Québec, Canada
| | | | - Imed E Gallouzi
- Department of Biochemistry, McGill University, Montréal, Québec, Canada
| | - Natasha C Chang
- Department of Biochemistry, McGill University, Montréal, Québec, Canada
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30
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Abstract
Abstract
In Trypanosoma brucei and related Kinetoplastids, regulation of gene expression occurs mostly post-transcriptionally, and RNA-binding proteins play a critical role in the regulation of mRNA and protein abundance. Trypanosoma brucei ZC3H28 is a 114 KDa cytoplasmic mRNA-binding protein with a single C(x)7C(x)5C(x)sH zinc finger at the C-terminus and numerous proline-, histidine- or glutamine-rich regions. ZC3H28 is essential for normal bloodstream-form trypanosome growth, and when tethered to a reporter mRNA, ZC3H28 increased reporter mRNA and protein levels. Purification of N-terminally tagged ZC3H28 followed by mass spectrometry showed enrichment of ribosomal proteins, various RNA-binding proteins including both poly(A) binding proteins, the translation initiation complex EIF4E4/EIF4G3, and the activator MKT1. Tagged ZC3H28 was preferentially associated with long RNAs that have low complexity sequences in their 3′-untranslated regions; their coding regions also have low ribosome densities. In agreement with the tethering results, after ZC3H28 depletion, the levels of a significant proportion of its bound mRNAs decreased. We suggest that ZC3H28 is implicated in the stabilization of long mRNAs that are poorly translated.
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31
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Burke JM, St Clair LA, Perera R, Parker R. SARS-CoV-2 infection triggers widespread host mRNA decay leading to an mRNA export block. RNA (NEW YORK, N.Y.) 2021; 27:1318-1329. [PMID: 34315815 PMCID: PMC8522697 DOI: 10.1261/rna.078923.121] [Citation(s) in RCA: 55] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Accepted: 07/21/2021] [Indexed: 05/16/2023]
Abstract
The transcriptional induction of interferon (IFN) genes is a key feature of the mammalian antiviral response that limits viral replication and dissemination. A hallmark of severe COVID-19 disease caused by SARS-CoV-2 is the low presence of IFN proteins in patient serum despite elevated levels of IFN-encoding mRNAs, indicative of post-transcriptional inhibition of IFN protein production. Here, we performed single-molecule RNA visualization to examine the expression and localization of host mRNAs during SARS-CoV-2 infection. Our data show that the biogenesis of type I and type III IFN mRNAs is inhibited at multiple steps during SARS-CoV-2 infection. First, translocation of the interferon regulatory factor 3 (IRF3) transcription factor to the nucleus is limited in response to SARS-CoV-2, indicating that SARS-CoV-2 inhibits RLR-MAVS signaling and thus weakens transcriptional induction of IFN genes. Second, we observed that IFN mRNAs primarily localize to the site of transcription in most SARS-CoV-2 infected cells, suggesting that SARS-CoV-2 either inhibits the release of IFN mRNAs from their sites of transcription and/or triggers decay of IFN mRNAs in the nucleus upon exiting the site of transcription. Lastly, nuclear-cytoplasmic transport of IFN mRNAs is inhibited during SARS-CoV-2 infection, which we propose is a consequence of widespread degradation of host cytoplasmic basal mRNAs in the early stages of SARS-CoV-2 replication by the SARS-CoV-2 Nsp1 protein, as well as the host antiviral endoribonuclease, RNase L. Importantly, IFN mRNAs can escape SARS-CoV-2-mediated degradation if they reach the cytoplasm, making rescue of mRNA export a viable means for promoting the immune response to SARS-CoV-2.
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Affiliation(s)
- James M Burke
- Department of Biochemistry, University of Colorado Boulder, Boulder, Colorado 80303, USA
| | - Laura A St Clair
- Center for Vector-Borne and Infectious Diseases, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado 80523, USA
- Center for Metabolism of Infectious Diseases, Colorado State University, Fort Collins, Colorado 80523, USA
| | - Rushika Perera
- Center for Vector-Borne and Infectious Diseases, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, Colorado 80523, USA
- Center for Metabolism of Infectious Diseases, Colorado State University, Fort Collins, Colorado 80523, USA
| | - Roy Parker
- Department of Biochemistry, University of Colorado Boulder, Boulder, Colorado 80303, USA
- Howard Hughes Medical Institute, University of Colorado Boulder, Boulder, Colorado 80303, USA
- BioFrontiers Institute, University of Colorado Boulder, Boulder, Colorado 80303, USA
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32
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Assis LA, Santos Filho MVC, da Cruz Silva JR, Bezerra MJR, de Aquino IRPUC, Merlo KC, Holetz FB, Probst CM, Rezende AM, Papadopoulou B, da Costa Lima TDC, de Melo Neto OP. Identification of novel proteins and mRNAs differentially bound to the Leishmania Poly(A) Binding Proteins reveals a direct association between PABP1, the RNA-binding protein RBP23 and mRNAs encoding ribosomal proteins. PLoS Negl Trop Dis 2021; 15:e0009899. [PMID: 34705820 PMCID: PMC8575317 DOI: 10.1371/journal.pntd.0009899] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2021] [Revised: 11/08/2021] [Accepted: 10/11/2021] [Indexed: 12/13/2022] Open
Abstract
Poly(A) Binding Proteins (PABPs) are major eukaryotic RNA-binding proteins (RBPs) with multiple roles associated with mRNA stability and translation and characterized mainly from multicellular organisms and yeasts. A variable number of PABP homologues are seen in different organisms however the biological reasons for multiple PABPs are generally not well understood. In the unicellular Leishmania, dependent on post-transcriptional mechanisms for the control of its gene expression, three distinct PABPs are found, with yet undefined functional distinctions. Here, using RNA-immunoprecipitation sequencing analysis we show that the Leishmania PABP1 preferentially associates with mRNAs encoding ribosomal proteins, while PABP2 and PABP3 bind to an overlapping set of mRNAs distinct to those enriched in PABP1. Immunoprecipitation studies combined to mass-spectrometry analysis identified RBPs differentially associated with PABP1 or PABP2, including RBP23 and DRBD2, respectively, that were investigated further. Both RBP23 and DRBD2 bind directly to the three PABPs in vitro, but reciprocal experiments confirmed preferential co-immunoprecipitation of PABP1, as well as the EIF4E4/EIF4G3 based translation initiation complex, with RBP23. Other RBP23 binding partners also imply a direct role in translation. DRBD2, in contrast, co-immunoprecipitated with PABP2, PABP3 and with RBPs unrelated to translation. Over 90% of the RBP23-bound mRNAs code for ribosomal proteins, mainly absent from the transcripts co-precipitated with DRBD2. These experiments suggest a novel and specific route for translation of the ribosomal protein mRNAs, mediated by RBP23, PABP1 and the associated EIF4E4/EIF4G3 complex. They also highlight the unique roles that different PABP homologues may have in eukaryotic cells associated with mRNA translation.
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Affiliation(s)
- Ludmila A. Assis
- Department of Microbiology, Aggeu Magalhães Institute, Oswaldo Cruz Foundation, Recife, Pernambuco, Brazil
- Department of Genetics, Federal University of Pernambuco, Recife, Pernambuco, Brazil
| | - Moezio V. C. Santos Filho
- Department of Microbiology, Aggeu Magalhães Institute, Oswaldo Cruz Foundation, Recife, Pernambuco, Brazil
- Department of Genetics, Federal University of Pernambuco, Recife, Pernambuco, Brazil
| | - Joao R. da Cruz Silva
- Department of Microbiology, Aggeu Magalhães Institute, Oswaldo Cruz Foundation, Recife, Pernambuco, Brazil
| | - Maria J. R. Bezerra
- Department of Microbiology, Aggeu Magalhães Institute, Oswaldo Cruz Foundation, Recife, Pernambuco, Brazil
| | | | - Kleison C. Merlo
- Department of Microbiology, Aggeu Magalhães Institute, Oswaldo Cruz Foundation, Recife, Pernambuco, Brazil
| | - Fabiola B. Holetz
- Laboratory of Gene Expression Regulation, Carlos Chagas Institute, Oswaldo Cruz Foundation, Curitiba, Paraná, Brazil
| | - Christian M. Probst
- Laboratory of Gene Expression Regulation, Carlos Chagas Institute, Oswaldo Cruz Foundation, Curitiba, Paraná, Brazil
| | - Antonio M. Rezende
- Department of Microbiology, Aggeu Magalhães Institute, Oswaldo Cruz Foundation, Recife, Pernambuco, Brazil
| | - Barbara Papadopoulou
- CHU de Quebec Research Center and Department of Microbiology-Infectious Disease and Immunology, Laval University, Quebec, Quebec, Canada
| | | | - Osvaldo P. de Melo Neto
- Department of Microbiology, Aggeu Magalhães Institute, Oswaldo Cruz Foundation, Recife, Pernambuco, Brazil
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33
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Ivanov P. Informosomes Travel in Time: An Early mRNA Concept in the Current mRNP Landscape. BIOCHEMISTRY (MOSCOW) 2021; 86:1044-1052. [PMID: 34565310 DOI: 10.1134/s0006297921090029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Messenger RNA is complexed with proteins throughout its life cycle. The first mRNA-containing particles of non-ribosomal nature, named informosomes, were discovered in cytoplasmic extracts of fish embryos by the laboratory of Alexander Spirin, and later described in live cells. Over time, various other nuclear and cytoplasmic mRNA-containing ribonucleoproteins (mRNPs) have been found and characterized. Although these mRNPs are very diverse in their subcellular localization, structure and functions, they share many common characteristics with informosomes. In this mini-review, I will discuss the discovery of informosomes, their characteristics and proposed functions, and their potential relationship to other mRNPs.
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Affiliation(s)
- Pavel Ivanov
- Division of Rheumatology, Inflammation, and Immunity, Brigham and Women's Hospital, Boston, MA 02115, USA. .,Department of Medicine, Harvard Medical School, Boston, MA 02115, USA.,Harvard Medical School Initiative for RNA Medicine, Harvard University, Boston, MA 02115, USA
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34
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Bao C, Ermolenko DN. Ribosome as a Translocase and Helicase. BIOCHEMISTRY (MOSCOW) 2021; 86:992-1002. [PMID: 34488575 PMCID: PMC8294220 DOI: 10.1134/s0006297921080095] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
During protein synthesis, ribosome moves along mRNA to decode one codon after the other. Ribosome translocation is induced by a universally conserved protein, elongation factor G (EF-G) in bacteria and elongation factor 2 (EF-2) in eukaryotes. EF-G-induced translocation results in unwinding of the intramolecular secondary structures of mRNA by three base pairs at a time that renders the translating ribosome a processive helicase. Professor Alexander Sergeevich Spirin has made numerous seminal contributions to understanding the molecular mechanism of translocation. Here, we review Spirin's insights into the ribosomal translocation and recent advances in the field that stemmed from Spirin's pioneering work. We also discuss key remaining challenges in studies of translocase and helicase activities of the ribosome.
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Affiliation(s)
- Chen Bao
- Department of Biochemistry & Biophysics, School of Medicine and Dentistry and Center for RNA Biology, University of Rochester, Rochester, NY, USA.
| | - Dmitri N Ermolenko
- Department of Biochemistry & Biophysics, School of Medicine and Dentistry and Center for RNA Biology, University of Rochester, Rochester, NY, USA.
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35
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Basyuk E, Rage F, Bertrand E. RNA transport from transcription to localized translation: a single molecule perspective. RNA Biol 2021; 18:1221-1237. [PMID: 33111627 PMCID: PMC8354613 DOI: 10.1080/15476286.2020.1842631] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2020] [Revised: 10/21/2020] [Accepted: 10/22/2020] [Indexed: 12/21/2022] Open
Abstract
Transport of mRNAs is an important step of gene expression, which brings the genetic message from the DNA in the nucleus to a precise cytoplasmic location in a regulated fashion. Perturbation of this process can lead to pathologies such as developmental and neurological disorders. In this review, we discuss recent advances in the field of mRNA transport made using single molecule fluorescent imaging approaches. We present an overview of these approaches in fixed and live cells and their input in understanding the key steps of mRNA journey: transport across the nucleoplasm, export through the nuclear pores and delivery to its final cytoplasmic location. This review puts a particular emphasis on the coupling of mRNA transport with translation, such as localization-dependent translational regulation and translation-dependent mRNA localization. We also highlight the recently discovered translation factories, and how cellular and viral RNAs can hijack membrane transport systems to travel in the cytoplasm.
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Affiliation(s)
- Eugenia Basyuk
- Institut de Génétique Humaine, CNRS-UMR9002, Univ Montpellier, Montpellier, France
- Present address: Laboratoire de Microbiologie Fondamentale et Pathogénicité, CNRS-UMR 5234, Université de Bordeaux, Bordeaux, France
| | - Florence Rage
- Institut de Génétique Moléculaire de Montpellier, CNRS-UMR5535, Univ Montpellier, Montpellier, France
| | - Edouard Bertrand
- Institut de Génétique Humaine, CNRS-UMR9002, Univ Montpellier, Montpellier, France
- Institut de Génétique Moléculaire de Montpellier, CNRS-UMR5535, Univ Montpellier, Montpellier, France
- Equipe Labélisée Ligue Nationale Contre Le Cancer, Montpellier, France
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36
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IRC3 regulates mitochondrial translation in response to metabolic cues in Saccharomyces cerevisiae. Mol Cell Biol 2021; 41:e0023321. [PMID: 34398681 DOI: 10.1128/mcb.00233-21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Mitochondrial oxidative phosphorylation (OXPHOS) enzymes are made up of dual genetic origin. Mechanisms regulating the expression of nuclear-encoded OXPHOS subunits in response to metabolic cues (glucose vs. glycerol), is significantly understood while regulation of mitochondrially encoded OXPHOS subunits is poorly defined. Here, we show that IRC3 a DEAD/H box helicase, previously implicated in mitochondrial DNA maintenance, is central to integrating metabolic cues with mitochondrial translation. Irc3 associates with mitochondrial small ribosomal subunit in cells consistent with its role in regulating translation elongation based on Arg8m reporter system. IRC3 deleted cells retained mitochondrial DNA despite growth defect on glycerol plates. Glucose grown Δirc3ρ+ and irc3 temperature-sensitive cells at 370C have reduced translation rates from majority of mRNAs. In contrast, when galactose was the carbon source, reduction in mitochondrial translation was observed predominantly from Cox1 mRNA in Δirc3ρ+ but no defect was observed in irc3 temperature-sensitive cells, at 370C. In support, of a model whereby IRC3 responds to metabolic cues to regulate mitochondrial translation, suppressors of Δirc3 isolated for restoration of growth on glycerol media restore mitochondrial protein synthesis differentially in presence of glucose vs. glycerol.
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37
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Burke JM, St Clair LA, Perera R, Parker R. Rapid decay of host basal mRNAs during SARS-CoV-2 infection perturbs host antiviral mRNA biogenesis and export. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2021:2021.04.19.440452. [PMID: 33907748 PMCID: PMC8077573 DOI: 10.1101/2021.04.19.440452] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
A key feature of the mammalian innate immune response to viral infection is the transcriptional induction of interferon (IFN) genes, which encode for secreted proteins that prime the antiviral response and limit viral replication and dissemination. A hallmark of severe COVID-19 disease caused by SARS-CoV-2 is the low presence of IFN proteins in patient serum despite elevated levels of IFN-encoding mRNAs, indicative of post-transcriptional inhibition of IFN protein production. Herein, we show SARS-CoV-2 infection limits type I and type III IFN biogenesis by preventing the release of mRNA from their sites of transcription and/or triggering their nuclear degradation. In addition, SARS-CoV-2 infection inhibits nuclear-cytoplasmic transport of IFN mRNAs as a consequence of widespread cytosolic mRNA degradation mediated by both activation of the host antiviral endoribonuclease, RNase L, and by the SARS-CoV-2 protein, Nsp1. These findings argue that inhibition of host and/or viral Nsp1-mediated mRNA decay, as well as IFN treatments, may reduce viral-associated pathogenesis by promoting the innate immune response.
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Affiliation(s)
- James M. Burke
- Department of Biochemistry, University of Colorado Boulder, Boulder, Colorado, 80303
| | - Laura A. St Clair
- Center for Vector-Borne and Infectious Diseases, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO 80523, USA
- Center for Metabolism of Infectious Diseases, Colorado State University, Fort Collins, CO 80523, USA
| | - Rushika Perera
- Center for Vector-Borne and Infectious Diseases, Department of Microbiology, Immunology and Pathology, Colorado State University, Fort Collins, CO 80523, USA
- Center for Metabolism of Infectious Diseases, Colorado State University, Fort Collins, CO 80523, USA
| | - Roy Parker
- Department of Biochemistry, University of Colorado Boulder, Boulder, Colorado, 80303
- Howard Hughes Medical Institute, University of Colorado Boulder, Boulder, Colorado, 80303
- BioFrontiers Institute, University of Colorado Boulder, Boulder, Colorado, 80303
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38
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Baba T, Tanimura S, Yamaguchi A, Horikawa K, Yokozeki M, Hachiya S, Iemura SI, Natsume T, Matsuda N, Takeda K. Cleaved PGAM5 dephosphorylates nuclear serine/arginine-rich proteins during mitophagy. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2021; 1868:119045. [PMID: 33872670 DOI: 10.1016/j.bbamcr.2021.119045] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 12/06/2020] [Revised: 04/02/2021] [Accepted: 04/13/2021] [Indexed: 01/23/2023]
Abstract
PGAM5 is a protein phosphatase located in the inner mitochondrial membrane through its transmembrane (TM) domain and is cleaved within the TM domain upon mitochondrial dysfunction. We found previously that cleaved PGAM5 is released from mitochondria, following proteasome-mediated rupture of the outer mitochondrial membrane during mitophagy, a selective form of autophagy specific to mitochondria. Here, we examined the role of cleaved PGAM5 outside mitochondria. Deletion mutants that mimic cleaved PGAM5 existed not only in the cytosol but also in the nucleus, and a fraction of cleaved PGAM5 translocated to the nucleus during mitophagy induced by the uncoupler CCCP. We identified serine/arginine-related nuclear matrix protein of 160 kDa (SRm160)/SRRM1, which contains a highly phosphorylated domain rich in arginine/serine dipeptides, called the RS domain, as a nuclear protein that interacts with PGAM5. PGAM5 dephosphorylated SRm160, and incubation of lysates from WT cells, but not of those from PGAM5-deficient cells, induced dephosphorylation of SRm160 and another RS domain-containing protein SRSF1, one of the most characterized serine/arginine-rich (SR) proteins. Moreover, phosphorylation of these proteins and other SR proteins, which are commonly reactive toward the 1H4 monoclonal antibody that detects phosphorylated SR proteins, decreased during mitophagy, largely because of PGAM5 activity. These results suggest that PGAM5 regulates phosphorylation of these nuclear proteins during mitophagy. Because SRm160 and SR proteins play critical roles in mRNA metabolism, PGAM5 may coordinate cellular responses to mitochondrial stress at least in part through post-transcriptional and pre-translational events.
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Affiliation(s)
- Taiki Baba
- Department of Cell Regulation, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki 852-8521, Japan
| | - Susumu Tanimura
- Department of Cell Regulation, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki 852-8521, Japan
| | - Ayane Yamaguchi
- Department of Cell Regulation, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki 852-8521, Japan
| | - Koichiro Horikawa
- Department of Cell Regulation, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki 852-8521, Japan
| | - Masashi Yokozeki
- Department of Cell Regulation, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki 852-8521, Japan
| | - Saki Hachiya
- Department of Cell Regulation, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki 852-8521, Japan
| | - Shun-Ichiro Iemura
- Translational Research Center, Fukushima Medical University, Fukushima 960-1295, Japan
| | - Tohru Natsume
- Cellular and Molecular Biotechnology Research Institute, National Institute of Advanced Industrial Science and Technology, Tokyo 135-0064, Japan
| | - Noriyuki Matsuda
- Ubiquitin Project, Tokyo Metropolitan Institute of Medical Science, Tokyo 156-8506, Japan
| | - Kohsuke Takeda
- Department of Cell Regulation, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki 852-8521, Japan.
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Melo do Nascimento L, Egler F, Arnold K, Papavasiliou N, Clayton C, Erben E. Functional insights from a surface antigen mRNA-bound proteome. eLife 2021; 10:e68136. [PMID: 33783358 PMCID: PMC8051951 DOI: 10.7554/elife.68136] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2021] [Accepted: 03/18/2021] [Indexed: 01/13/2023] Open
Abstract
Trypanosoma brucei is the causative agent of human sleeping sickness. The parasites' variant surface glycoprotein (VSG) enables them to evade adaptive immunity via antigenic variation. VSG comprises 10% of total cell protein and the high stability of VSG mRNA is essential for trypanosome survival. To determine how VSG mRNA stability is maintained, we used mRNA affinity purification to identify all its associated proteins. CFB2 (cyclin F-box protein 2), an unconventional RNA-binding protein with an F-box domain, was specifically enriched with VSG mRNA. We demonstrate that CFB2 is essential for VSG mRNA stability, describe cis acting elements within the VSG 3'-untranslated region that regulate the interaction, identify trans-acting factors that are present in the VSG messenger ribonucleoprotein particle, and mechanistically explain how CFB2 stabilizes the mRNA of this key pathogenicity factor. Beyond T. brucei, the mRNP purification approach has the potential to supply detailed biological insight into metabolism of relatively abundant mRNAs in any eukaryote.
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Affiliation(s)
| | - Franziska Egler
- Centre for Molecular Biology of Heidelberg University (ZMBH)HeidelbergGermany
| | - Katharina Arnold
- Centre for Molecular Biology of Heidelberg University (ZMBH)HeidelbergGermany
| | - Nina Papavasiliou
- Division of Immune Diversity, Deutsche Krebsforschungszentrum (DKFZ)HeidelbergGermany
| | - Christine Clayton
- Centre for Molecular Biology of Heidelberg University (ZMBH)HeidelbergGermany
| | - Esteban Erben
- Centre for Molecular Biology of Heidelberg University (ZMBH)HeidelbergGermany
- Division of Immune Diversity, Deutsche Krebsforschungszentrum (DKFZ)HeidelbergGermany
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40
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Ho JJD, Man JHS, Schatz JH, Marsden PA. Translational remodeling by RNA-binding proteins and noncoding RNAs. WILEY INTERDISCIPLINARY REVIEWS-RNA 2021; 12:e1647. [PMID: 33694288 DOI: 10.1002/wrna.1647] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Revised: 02/09/2021] [Accepted: 02/10/2021] [Indexed: 12/14/2022]
Abstract
Responsible for generating the proteome that controls phenotype, translation is the ultimate convergence point for myriad upstream signals that influence gene expression. System-wide adaptive translational reprogramming has recently emerged as a pillar of cellular adaptation. As classic regulators of mRNA stability and translation efficiency, foundational studies established the concept of collaboration and competition between RNA-binding proteins (RBPs) and noncoding RNAs (ncRNAs) on individual mRNAs. Fresh conceptual innovations now highlight stress-activated, evolutionarily conserved RBP networks and ncRNAs that increase the translation efficiency of populations of transcripts encoding proteins that participate in a common cellular process. The discovery of post-transcriptional functions for long noncoding RNAs (lncRNAs) was particularly intriguing given their cell-type-specificity and historical definition as nuclear-functioning epigenetic regulators. The convergence of RBPs, lncRNAs, and microRNAs on functionally related mRNAs to enable adaptive protein synthesis is a newer biological paradigm that highlights their role as "translatome (protein output) remodelers" and reinvigorates the paradigm of "RNA operons." Together, these concepts modernize our understanding of cellular stress adaptation and strategies for therapeutic development. This article is categorized under: RNA Interactions with Proteins and Other Molecules > Protein-RNA Interactions: Functional Implications Translation > Translation Regulation Regulatory RNAs/RNAi/Riboswitches > Regulatory RNAs.
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Affiliation(s)
- J J David Ho
- Sylvester Comprehensive Cancer Center, Miller School of Medicine, University of Miami, Miami, Florida, USA.,Division of Hematology, Department of Medicine, Miller School of Medicine, University of Miami, Miami, Florida, USA
| | - Jeffrey H S Man
- Keenan Research Centre, Li Ka Shing Knowledge Institute, St. Michael's Hospital, Toronto, Ontario, Canada.,Department of Medicine, University of Toronto, Toronto, Ontario, Canada.,Department of Respirology, University Health Network, Latner Thoracic Research Laboratories, University of Toronto, Toronto, Ontario, Canada
| | - Jonathan H Schatz
- Sylvester Comprehensive Cancer Center, Miller School of Medicine, University of Miami, Miami, Florida, USA.,Division of Hematology, Department of Medicine, Miller School of Medicine, University of Miami, Miami, Florida, USA
| | - Philip A Marsden
- Keenan Research Centre, Li Ka Shing Knowledge Institute, St. Michael's Hospital, Toronto, Ontario, Canada.,Department of Medicine, University of Toronto, Toronto, Ontario, Canada
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41
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Kinoshita C, Kikuchi-Utsumi K, Aoyama K, Suzuki R, Okamoto Y, Matsumura N, Omata D, Maruyama K, Nakaki T. Inhibition of miR-96-5p in the mouse brain increases glutathione levels by altering NOVA1 expression. Commun Biol 2021; 4:182. [PMID: 33568779 PMCID: PMC7876013 DOI: 10.1038/s42003-021-01706-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2020] [Accepted: 01/15/2021] [Indexed: 12/26/2022] Open
Abstract
Glutathione (GSH) is an important antioxidant that plays a critical role in neuroprotection. GSH depletion in neurons induces oxidative stress and thereby promotes neuronal damage, which in turn is regarded as a hallmark of the early stage of neurodegenerative diseases. The neuronal GSH level is mainly regulated by cysteine transporter EAAC1 and its inhibitor, GTRAP3-18. In this study, we found that the GTRAP3-18 level was increased by up-regulation of the microRNA miR-96-5p, which was found to decrease EAAC1 levels in our previous study. Since the 3'-UTR region of GTRAP3-18 lacks the consensus sequence for miR-96-5p, an unidentified protein should be responsible for the intermediate regulation of GTRAP3-18 expression by miR-96-5p. Here, we discovered that RNA-binding protein NOVA1 functions as an intermediate protein for GTRAP3-18 expression via miR-96-5p. Moreover, we show that intra-arterial injection of a miR-96-5p-inhibiting nucleic acid to living mice by a drug delivery system using microbubbles and ultrasound decreased the level of GTRAP3-18 via NOVA1 and increased the levels of EAAC1 and GSH in the dentate gyrus of the hippocampus. These findings suggest that the delivery of a miR-96-5p inhibitor to the brain would efficiently increase the neuroprotective activity by increasing GSH levels via EAAC1, GTRAP3-18 and NOVA1.
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Affiliation(s)
- Chisato Kinoshita
- Department of Pharmacology, Teikyo University School of Medicine, Tokyo, Japan
| | | | - Koji Aoyama
- Department of Pharmacology, Teikyo University School of Medicine, Tokyo, Japan
| | - Ryo Suzuki
- Laboratory of Drug and Gene Delivery, Faculty of Pharma-Science, Teikyo University, Tokyo, Japan
| | - Yayoi Okamoto
- Department of Pharmacology, Teikyo University School of Medicine, Tokyo, Japan
- Teikyo University Support Center for Women Physicians and Researchers, Tokyo, Japan
| | - Nobuko Matsumura
- Department of Pharmacology, Teikyo University School of Medicine, Tokyo, Japan
| | - Daiki Omata
- Laboratory of Drug and Gene Delivery, Faculty of Pharma-Science, Teikyo University, Tokyo, Japan
| | - Kazuo Maruyama
- Laboratory of Theranostics, Faculty of Pharma-Science, Teikyo University, Tokyo, Japan
| | - Toshio Nakaki
- Department of Pharmacology, Teikyo University School of Medicine, Tokyo, Japan.
- Faculty of Pharma-Science, Teikyo University, Tokyo, Japan.
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42
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Abstract
Trypanosoma brucei is unusually reliant on mRNA-binding proteins to control mRNA fate, because its protein-coding genes lack individual promoters. We here focus on three trypanosome RNA-binding proteins. ZC3H22 is specific to Tsetse fly forms, RBP9 is preferentially expressed in bloodstream forms; and DRBD7 is constitutively expressed. Depletion of RBP9 or DRBD7 did not affect bloodstream-form trypanosome growth. ZC3H22 depletion from procyclic forms caused cell clumping, decreased expression of genes required for cell growth and proliferation, and increased expression of some epimastigote markers. Apart from decreases in mRNAs encoding enzymes of glucose metabolism, levels of most ZC3H22-bound transcripts were unaffected by ZC3H22 depletion. We compared ZC3H22, RBP9 and DRBD7 RNA binding with that of 16 other RNA-binding proteins. ZC3H22, PUF3 and ERBP1 show a preference for ribosomal protein mRNAs. RBP9 preferentially binds mRNAs that are more abundant in bloodstream forms than in procyclic forms. RBP9, ZC3H5, ZC3H30 and DRBD7 prefer mRNAs with long coding regions; UBP1-associated mRNAs have long 3′-untranslated regions; and RRM1 prefers mRNAs with long 3′or 5′-untranslated regions. We suggest that proteins that prefer long mRNAs may have relatively short or degenerate binding sites, and that preferences for A or U increase binding in untranslated regions.
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43
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Irastortza-Olaziregi M, Amster-Choder O. Coupled Transcription-Translation in Prokaryotes: An Old Couple With New Surprises. Front Microbiol 2021; 11:624830. [PMID: 33552035 PMCID: PMC7858274 DOI: 10.3389/fmicb.2020.624830] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2020] [Accepted: 12/18/2020] [Indexed: 01/17/2023] Open
Abstract
Coupled transcription-translation (CTT) is a hallmark of prokaryotic gene expression. CTT occurs when ribosomes associate with and initiate translation of mRNAs whose transcription has not yet concluded, therefore forming "RNAP.mRNA.ribosome" complexes. CTT is a well-documented phenomenon that is involved in important gene regulation processes, such as attenuation and operon polarity. Despite the progress in our understanding of the cellular signals that coordinate CTT, certain aspects of its molecular architecture remain controversial. Additionally, new information on the spatial segregation between the transcriptional and the translational machineries in certain species, and on the capability of certain mRNAs to localize translation-independently, questions the unanimous occurrence of CTT. Furthermore, studies where transcription and translation were artificially uncoupled showed that transcription elongation can proceed in a translation-independent manner. Here, we review studies supporting the occurrence of CTT and findings questioning its extent, as well as discuss mechanisms that may explain both coupling and uncoupling, e.g., chromosome relocation and the involvement of cis- or trans-acting elements, such as small RNAs and RNA-binding proteins. These mechanisms impact RNA localization, stability, and translation. Understanding the two options by which genes can be expressed and their consequences should shed light on a new layer of control of bacterial transcripts fate.
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Affiliation(s)
- Mikel Irastortza-Olaziregi
- Department of Microbiology and Molecular Genetics, Faculty of Medicine, IMRIC, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Orna Amster-Choder
- Department of Microbiology and Molecular Genetics, Faculty of Medicine, IMRIC, The Hebrew University of Jerusalem, Jerusalem, Israel
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44
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Mateu-Regué À, Nielsen FC, Christiansen J. Cytoplasmic mRNPs revisited: Singletons and condensates. Bioessays 2020; 42:e2000097. [PMID: 33145808 DOI: 10.1002/bies.202000097] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Revised: 09/04/2020] [Indexed: 01/01/2023]
Abstract
Cytoplasmic messenger ribonucleoprotein particles (mRNPs) represent the cellular transcriptome, and recent data have challenged our current understanding of their architecture, transport, and complexity before translation. Pre-translational mRNPs are composed of a single transcript, whereas P-bodies and stress granules are condensates. Both pre-translational mRNPs and actively translating mRNPs seem to adopt a linear rather than a closed-loop configuration. Moreover, assembly of pre-translational mRNPs in physical RNA regulons is an unlikely event, and co-regulated translation may occur locally following extracellular cues. We envisage a stochastic mRNP transport mechanism where translational repression of single mRNPs-in combination with microtubule-mediated cytoplasmic streaming and docking events-are prerequisites for local translation, rather than direct transport.
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Affiliation(s)
| | | | - Jan Christiansen
- Department of Biology, University of Copenhagen, Copenhagen, Denmark
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45
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Muthunayake NS, Tomares DT, Childers WS, Schrader JM. Phase-separated bacterial ribonucleoprotein bodies organize mRNA decay. WILEY INTERDISCIPLINARY REVIEWS. RNA 2020; 11:e1599. [PMID: 32445438 PMCID: PMC7554086 DOI: 10.1002/wrna.1599] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2020] [Revised: 04/16/2020] [Accepted: 04/17/2020] [Indexed: 01/12/2023]
Abstract
In bacteria, mRNA decay is controlled by megadalton scale macromolecular assemblies called, "RNA degradosomes," composed of nucleases and other RNA decay associated proteins. Recent advances in bacterial cell biology have shown that RNA degradosomes can assemble into phase-separated structures, termed bacterial ribonucleoprotein bodies (BR-bodies), with many analogous properties to eukaryotic processing bodies and stress granules. This review will highlight the functional role that BR-bodies play in the mRNA decay process through its organization into a membraneless organelle in the bacterial cytoplasm. This review will also highlight the phylogenetic distribution of BR-bodies across bacterial species, which suggests that these phase-separated structures are broadly distributed across bacteria, and in evolutionarily related mitochondria and chloroplasts. This article is categorized under: RNA Turnover and Surveillance > Turnover/Surveillance Mechanisms RNA Interactions with Proteins and Other Molecules > RNA-Protein Complexes RNA Export and Localization > RNA Localization RNA Turnover and Surveillance > Regulation of RNA Stability.
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Affiliation(s)
| | - Dylan T Tomares
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - W Seth Childers
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Jared M Schrader
- Department of Biological Sciences, Wayne State University, Detroit, Michigan, USA
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46
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Garrido-Godino AI, Gupta I, Gutiérrez-Santiago F, Martínez-Padilla AB, Alekseenko A, Steinmetz LM, Pérez-Ortín JE, Pelechano V, Navarro F. Rpb4 and Puf3 imprint and post-transcriptionally control the stability of a common set of mRNAs in yeast. RNA Biol 2020; 18:1206-1220. [PMID: 33094674 DOI: 10.1080/15476286.2020.1839229] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Gene expression involving RNA polymerase II is regulated by the concerted interplay between mRNA synthesis and degradation, crosstalk in which mRNA decay machinery and transcription machinery respectively impact transcription and mRNA stability. Rpb4, and likely dimer Rpb4/7, seem the central components of the RNA pol II governing these processes. In this work we unravel the molecular mechanisms participated by Rpb4 that mediate the posttranscriptional events regulating mRNA imprinting and stability. By RIP-Seq, we analysed genome-wide the association of Rpb4 with mRNAs and demonstrated that it targeted a large population of more than 1400 transcripts. A group of these mRNAs was also the target of the RNA binding protein, Puf3. We demonstrated that Rpb4 and Puf3 physically, genetically, and functionally interact and also affect mRNA stability, and likely the imprinting, of a common group of mRNAs. Furthermore, the Rpb4 and Puf3 association with mRNAs depends on one another. We also demonstrated, for the first time, that Puf3 associates with chromatin in an Rpb4-dependent manner. Our data also suggest that Rpb4 could be a key element of the RNA pol II that coordinates mRNA synthesis, imprinting and stability in cooperation with RBPs.
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Affiliation(s)
- A I Garrido-Godino
- Departamento de Biología Experimental-Genética, Universidad de Jaén, Jaén, Spain
| | - I Gupta
- Department of Biochemical Engineering and Biotechnology, IIT Delhi, Hauz Khas, India
| | - F Gutiérrez-Santiago
- Departamento de Biología Experimental-Genética, Universidad de Jaén, Jaén, Spain
| | - A B Martínez-Padilla
- Departamento de Biología Experimental-Genética, Universidad de Jaén, Jaén, Spain
| | - A Alekseenko
- SciLifeLab, Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Solna, Sweden
| | - L M Steinmetz
- European Molecular Biology Laboratory (EMBL), Genome Biology Unit, Heidelberg, Germany.,Stanford Genome Technology Center, Stanford University, Palo Alto, CA, USA.,Department of Genetics, School of Medicine, Stanford University, Stanford, CA, USA
| | - J E Pérez-Ortín
- E.R.I. Biotecmed, Facultad de Biológicas, Universitat de València, Burjassot, Spain
| | - V Pelechano
- SciLifeLab, Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Solna, Sweden
| | - F Navarro
- Departamento de Biología Experimental-Genética, Universidad de Jaén, Jaén, Spain.,Centro de Estudios Avanzados en Aceite de Oliva y Olivar, Universidad de Jaén, Jaén, Spain
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47
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Zarnack K, Balasubramanian S, Gantier MP, Kunetsky V, Kracht M, Schmitz ML, Sträßer K. Dynamic mRNP Remodeling in Response to Internal and External Stimuli. Biomolecules 2020; 10:biom10091310. [PMID: 32932892 PMCID: PMC7565591 DOI: 10.3390/biom10091310] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Revised: 09/02/2020] [Accepted: 09/08/2020] [Indexed: 02/06/2023] Open
Abstract
Signal transduction and the regulation of gene expression are fundamental processes in every cell. RNA-binding proteins (RBPs) play a key role in the post-transcriptional modulation of gene expression in response to both internal and external stimuli. However, how signaling pathways regulate the assembly of RBPs with mRNAs remains largely unknown. Here, we summarize observations showing that the formation and composition of messenger ribonucleoprotein particles (mRNPs) is dynamically remodeled in space and time by specific signaling cascades and the resulting post-translational modifications. The integration of signaling events with gene expression is key to the rapid adaptation of cells to environmental changes and stress. Only a combined approach analyzing the signal transduction pathways and the changes in post-transcriptional gene expression they cause will unravel the mechanisms coordinating these important cellular processes.
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Affiliation(s)
- Kathi Zarnack
- Buchmann Institute for Molecular Life Sciences, Goethe University Frankfurt, 60438 Frankfurt a.M., Germany;
| | | | - Michael P. Gantier
- Centre for Innate Immunity and Infectious Diseases, Hudson Institute of Medical Research, Clayton, VIC 3168, Australia;
- Department of Molecular and Translational Science, Monash University, Clayton, VIC 3800, Australia
| | - Vladislav Kunetsky
- Institute of Biochemistry, FB08, Justus Liebig University, 35392 Giessen, Germany;
| | - Michael Kracht
- Rudolf Buchheim Institute of Pharmacology, FB11, Justus Liebig University, 35392 Giessen, Germany;
| | - M. Lienhard Schmitz
- Institute of Biochemistry, FB11, Justus Liebig University, 35392 Giessen, Germany;
| | - Katja Sträßer
- Institute of Biochemistry, FB08, Justus Liebig University, 35392 Giessen, Germany;
- Correspondence:
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48
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Tauber D, Tauber G, Parker R. Mechanisms and Regulation of RNA Condensation in RNP Granule Formation. Trends Biochem Sci 2020; 45:764-778. [PMID: 32475683 PMCID: PMC7211619 DOI: 10.1016/j.tibs.2020.05.002] [Citation(s) in RCA: 102] [Impact Index Per Article: 25.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Revised: 04/20/2020] [Accepted: 05/05/2020] [Indexed: 01/01/2023]
Abstract
Ribonucleoprotein (RNP) granules are RNA-protein assemblies that are involved in multiple aspects of RNA metabolism and are linked to memory, development, and disease. Some RNP granules form, in part, through the formation of intermolecular RNA-RNA interactions. In vitro, such trans RNA condensation occurs readily, suggesting that cells require mechanisms to modulate RNA-based condensation. We assess the mechanisms of RNA condensation and how cells modulate this phenomenon. We propose that cells control RNA condensation through ATP-dependent processes, static RNA buffering, and dynamic post-translational mechanisms. Moreover, perturbations in these mechanisms can be involved in disease. This reveals multiple cellular mechanisms of kinetic and thermodynamic control that maintain the proper distribution of RNA molecules between dispersed and condensed forms.
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Affiliation(s)
- Devin Tauber
- Department of Biochemistry, University of Colorado Boulder, Boulder, CO 80308, USA
| | - Gabriel Tauber
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Roy Parker
- Department of Biochemistry, University of Colorado Boulder, Boulder, CO 80308, USA; Howard Hughes Medical Institute, University of Colorado Boulder, Boulder, CO 80308, USA.
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49
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Ermolenko DN, Mathews DH. Making ends meet: New functions of mRNA secondary structure. WILEY INTERDISCIPLINARY REVIEWS-RNA 2020; 12:e1611. [PMID: 32597020 DOI: 10.1002/wrna.1611] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2020] [Revised: 05/19/2020] [Accepted: 05/19/2020] [Indexed: 11/10/2022]
Abstract
The 5' cap and 3' poly(A) tail of mRNA are known to synergistically regulate mRNA translation and stability. Recent computational and experimental studies revealed that both protein-coding and non-coding RNAs will fold with extensive intramolecular secondary structure, which will result in close distances between the sequence ends. This proximity of the ends is a sequence-independent, universal property of most RNAs. Only low-complexity sequences without guanosines are without secondary structure and exhibit end-to-end distances expected for RNA random coils. The innate proximity of RNA ends might have important biological implications that remain unexplored. In particular, the inherent compactness of mRNA might regulate translation initiation by facilitating the formation of protein complexes that bridge mRNA 5' and 3' ends. Additionally, the proximity of mRNA ends might mediate coupling of 3' deadenylation to 5' end mRNA decay. This article is categorized under: RNA Structure and Dynamics > RNA Structure, Dynamics, and Chemistry RNA Structure and Dynamics > Influence of RNA Structure in Biological Systems Translation > Translation Regulation.
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Affiliation(s)
- Dmitri N Ermolenko
- Department of Biochemistry & Biophysics and Center for RNA Biology, School of Medicine and Dentistry, University of Rochester, Rochester, New York, USA
| | - David H Mathews
- Department of Biochemistry & Biophysics and Center for RNA Biology, School of Medicine and Dentistry, University of Rochester, Rochester, New York, USA
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50
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Melo do Nascimento L, Terrao M, Marucha KK, Liu B, Egler F, Clayton C. The RNA-associated proteins MKT1 and MKT1L form alternative PBP1-containing complexes in Trypanosoma brucei. J Biol Chem 2020; 295:10940-10955. [PMID: 32532821 DOI: 10.1074/jbc.ra120.013306] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Revised: 06/03/2020] [Indexed: 01/20/2023] Open
Abstract
Control of gene expression in kinetoplastids such as trypanosomes depends heavily on RNA-binding proteins that influence mRNA decay and translation. We previously showed that the trypanosome protein MKT1 forms a multicomponent protein complex: MKT1 interacts with PBP1, which in turn recruits LSM12 and poly(A)-binding protein. MKT1 is recruited to mRNAs by sequence-specific RNA-binding proteins, resulting in stabilization of the bound mRNA. We here show that PBP1, LSM12, and a 117-residue protein, XAC1 (Tb927.7.2780), are present in complexes that contain either MKT1 or an MKT1-like protein, MKT1L (Tb927.10.1490). All five proteins are present predominantly in the complexes, and we found evidence for a minor subset of complexes containing both MKT1 and MKT1L. XAC1-containing complexes reproducibly contained RNA-binding proteins that were previously found associated with MKT1. Moreover, XAC1- or MKT1-containing complexes specifically recruited one of the two poly(A)-binding proteins, PABP2, and one of the six cap-binding translation initiation complexes, EIF4E6-EIF4G5. Yeast two-hybrid assay results indicated that MKT1 directly interacts with EIF4G5. MKT1-PBP1 complexes can therefore interact with mRNAs via their poly(A) tails and caps, as well as through sequence-specific RNA-binding proteins. Correspondingly, MKT1 is associated with many mRNAs, although not with those encoding ribosomal proteins. Meanwhile, MKT1L resembles MKT1 at the C terminus but additionally features an N-terminal extension with low-complexity regions. Although MKT1L depletion inhibited cell proliferation, we found no evidence that it specifically interacts with RNA-binding proteins or mRNA. We speculate that MKT1L may compete with MKT1 for PBP1 binding and thereby modulate the function of MKT1-containing complexes.
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Affiliation(s)
| | - Monica Terrao
- Heidelberg University Centre for Molecular Biology (ZMBH), Heidelberg, Germany
| | | | - Bin Liu
- Heidelberg University Centre for Molecular Biology (ZMBH), Heidelberg, Germany
| | - Franziska Egler
- Heidelberg University Centre for Molecular Biology (ZMBH), Heidelberg, Germany
| | - Christine Clayton
- Heidelberg University Centre for Molecular Biology (ZMBH), Heidelberg, Germany
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