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Sudheesh AP, Mohan N, Francis N, Laishram RS, Anderson RA. Star-PAP controlled alternative polyadenylation coupled poly(A) tail length regulates protein expression in hypertrophic heart. Nucleic Acids Res 2020; 47:10771-10787. [PMID: 31598705 PMCID: PMC6847588 DOI: 10.1093/nar/gkz875] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2018] [Revised: 09/08/2019] [Accepted: 10/05/2019] [Indexed: 12/31/2022] Open
Abstract
Alternative polyadenylation (APA)-mediated 3′-untranslated region (UTR) shortening is known to increase protein expression due to the loss of miRNA regulatory sites. Yet, mRNAs with longer 3′-UTR also show enhanced protein expression. Here, we identify a mechanism by which longer transcripts generated by the distal-most APA site leads to increased protein expression compared to the shorter transcripts and the longer transcripts are positioned to regulate heart failure (HF). A Star-PAP target gene, NQO1 has three poly(A) sites (PA-sites) at the terminal exon on the pre-mRNA. Star-PAP selects the distal-most site that results in the expression of the longest isoform. We show that the NQO1 distal-specific mRNA isoform accounts for the majority of cellular NQO1 protein. Star-PAP control of the distal-specific isoform is stimulated by oxidative stress and the toxin dioxin. The longest NQO1 transcript has increased poly(A) tail (PA-tail) length that accounts for the difference in translation potentials of the three NQO1 isoforms. This mechanism is involved in the regulation of cardiac hypertrophy (CH), an antecedent condition to HF where NQO1 downregulation stems from the loss of the distal-specific transcript. The loss of NQO1 during hypertrophy was rescued by ectopic expression of the distal- but not the proximal- or middle-specific NQO1 mRNA isoforms in the presence of Star-PAP expression, and reverses molecular events of hypertrophy in cardiomyocytes.
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Affiliation(s)
- A P Sudheesh
- Cardiovascular and Diabetes Biology Group, Rajiv Gandhi Centre for Biotechnology, Trivandrum-014, India.,Manipal Academy of Higher Education, Manipal 576104, India
| | - Nimmy Mohan
- Cardiovascular and Diabetes Biology Group, Rajiv Gandhi Centre for Biotechnology, Trivandrum-014, India.,Manipal Academy of Higher Education, Manipal 576104, India
| | - Nimmy Francis
- Cardiovascular and Diabetes Biology Group, Rajiv Gandhi Centre for Biotechnology, Trivandrum-014, India.,Manipal Academy of Higher Education, Manipal 576104, India
| | - Rakesh S Laishram
- Cardiovascular and Diabetes Biology Group, Rajiv Gandhi Centre for Biotechnology, Trivandrum-014, India
| | - Richard A Anderson
- School of Medicine and Public Health, University of Wisconsin, MD 53726, USA
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52
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Lee SE, Alcedo KP, Kim HJ, Snider NT. Alternative Splicing in Hepatocellular Carcinoma. Cell Mol Gastroenterol Hepatol 2020; 10:699-712. [PMID: 32389640 PMCID: PMC7490524 DOI: 10.1016/j.jcmgh.2020.04.018] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/11/2020] [Revised: 04/24/2020] [Accepted: 04/27/2020] [Indexed: 02/06/2023]
Abstract
Hepatocellular carcinoma (HCC) accounts for the majority of primary liver cancer cases, with more than 850,000 new diagnoses per year globally. Recent trends in the United States have shown that liver cancer mortality has continued to increase in both men and women, while 5-year survival remains below 20%. Understanding key mechanisms that drive chronic liver disease progression to HCC can reveal new therapeutic targets and biomarkers for early detection of HCC. In that regard, many studies have underscored the importance of alternative splicing as a source of novel HCC prognostic markers and disease targets. Alternative splicing of pre-mRNA provides functional diversity to the genome, and endows cells with the ability to rapidly remodel the proteome. Genes that control fundamental processes, such as metabolism, cell proliferation, and apoptosis, are altered globally in HCC by alternative splicing. This review highlights the major splicing factors, RNA binding proteins, transcriptional targets, and signaling pathways that are of key relevance to HCC. We highlight primary research from the past 3-5 years involving functional interrogation of alternative splicing in rodent and human liver, using both large-scale transcriptomic and focused mechanistic approaches. Because this is a rapidly advancing field, we anticipate that it will be transformative for the future of basic liver biology, as well as HCC diagnosis and management.
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Affiliation(s)
- Seung Eun Lee
- Department of Surgery, Chung-Ang University, Seoul, Korea,Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Karel P. Alcedo
- Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Hong Jin Kim
- Department of Surgery, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Natasha T. Snider
- Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina,Correspondence Address correspondence to: Natasha Snider, PhD, Department of Cell Biology and Physiology, University of North Carolina–Chapel Hill, 5340C MBRB, 111 Mason Farm Road, Chapel Hill, North Carolina 27516. fax: (919) 966-6927.
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53
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Tsai YL, Coady TH, Lu L, Zheng D, Alland I, Tian B, Shneider NA, Manley JL. ALS/FTD-associated protein FUS induces mitochondrial dysfunction by preferentially sequestering respiratory chain complex mRNAs. Genes Dev 2020; 34:785-805. [PMID: 32381627 PMCID: PMC7263147 DOI: 10.1101/gad.335836.119] [Citation(s) in RCA: 50] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2019] [Accepted: 04/09/2020] [Indexed: 12/12/2022]
Abstract
Dysregulation of the DNA/RNA-binding protein FUS causes certain subtypes of ALS/FTD by largely unknown mechanisms. Recent evidence has shown that FUS toxic gain of function due either to mutations or to increased expression can disrupt critical cellular processes, including mitochondrial functions. Here, we demonstrate that in human cells overexpressing wild-type FUS or expressing mutant derivatives, the protein associates with multiple mRNAs, and these are enriched in mRNAs encoding mitochondrial respiratory chain components. Notably, this sequestration leads to reduced levels of the encoded proteins, which is sufficient to bring about disorganized mitochondrial networks, reduced aerobic respiration and increased reactive oxygen species. We further show that mutant FUS associates with mitochondria and with mRNAs encoded by the mitochondrial genome. Importantly, similar results were also observed in fibroblasts derived from ALS patients with FUS mutations. Finally, we demonstrate that FUS loss of function does not underlie the observed mitochondrial dysfunction, and also provides a mechanism for the preferential sequestration of the respiratory chain complex mRNAs by FUS that does not involve sequence-specific binding. Together, our data reveal that respiratory chain complex mRNA sequestration underlies the mitochondrial defects characteristic of ALS/FTD and contributes to the FUS toxic gain of function linked to this disease spectrum.
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Affiliation(s)
- Yueh-Lin Tsai
- Department of Biological Sciences, Columbia University, New York, New York 10027, USA
| | - Tristan H Coady
- Department of Biological Sciences, Columbia University, New York, New York 10027, USA
| | - Lei Lu
- Center for Motor Neuron Biology and Disease, Columbia University, New York, New York 10027, USA
| | - Dinghai Zheng
- Department of Microbiology, Biochemistry, and Molecular Genetics, Rutgers New Jersey Medical School, Newark, New Jersey 07103, USA
| | - Isabel Alland
- Department of Biological Sciences, Columbia University, New York, New York 10027, USA
| | - Bin Tian
- Department of Microbiology, Biochemistry, and Molecular Genetics, Rutgers New Jersey Medical School, Newark, New Jersey 07103, USA
| | - Neil A Shneider
- Center for Motor Neuron Biology and Disease, Columbia University, New York, New York 10027, USA
| | - James L Manley
- Department of Biological Sciences, Columbia University, New York, New York 10027, USA
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54
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Aoki H, Yamashita M, Hashita T, Ogami K, Hoshino S, Iwao T, Matsunaga T. Efficient differentiation and purification of human induced pluripotent stem cell-derived endothelial progenitor cells and expansion with the use of inhibitors of ROCK, TGF-β, and GSK3β. Heliyon 2020; 6:e03493. [PMID: 32154424 PMCID: PMC7056658 DOI: 10.1016/j.heliyon.2020.e03493] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2019] [Revised: 02/14/2020] [Accepted: 02/24/2020] [Indexed: 01/29/2023] Open
Abstract
Endothelial cells (ECs) and endothelial progenitor cells (EPCs) play crucial roles in maintaining vascular health and homeostasis. Both cell types have been used in regenerative therapy as well as in various in vitro models; however, the properties of primary human ECs and EPCs are dissimilar owing to differences in genetic backgrounds and sampling techniques. Human induced pluripotent stem cells (hiPSCs) are an alternative cell source of ECs and EPCs. However, owing to the low purity of differentiated cells from hiPSCs, purification via an antigen–antibody reaction, which damages the cells, is indispensable. Besides, owing to limited expandability, it is difficult to produce these cells in large numbers. Here we report the development of relatively simple differentiation and purification methods for hiPSC-derived EPCs (iEPCs). Furthermore, we discovered that a combination of three small molecules, that is, Y-27632 (a selective inhibitor of Rho-associated, coiled-coil containing protein kinase [ROCK]), A 83–01 (a receptor-like kinase inhibitor of transforming growth factor beta [TGF-β]), and CHIR-99021 (a selective inhibitor of glycogen synthase kinase-3β [GSK3β] that also activates Wnt), dramatically stimulated protein synthesis-related pathways and enhanced the proliferative capacity of iEPCs. These findings will help to establish a supply system of EPCs at an industrial scale.
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Affiliation(s)
- Hiromasa Aoki
- Department of Clinical Pharmacy, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya, 467-8603, Japan
| | - Misaki Yamashita
- Department of Clinical Pharmacy, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya, 467-8603, Japan
| | - Tadahiro Hashita
- Department of Clinical Pharmacy, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya, 467-8603, Japan
| | - Koichi Ogami
- Department of Biological Chemistry, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya, 467-8603, Japan
| | - Shinichi Hoshino
- Department of Biological Chemistry, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya, 467-8603, Japan
| | - Takahiro Iwao
- Department of Clinical Pharmacy, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya, 467-8603, Japan
| | - Tamihide Matsunaga
- Department of Clinical Pharmacy, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya, 467-8603, Japan
- Corresponding author.
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55
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Elrod ND, Henriques T, Huang KL, Tatomer DC, Wilusz JE, Wagner EJ, Adelman K. The Integrator Complex Attenuates Promoter-Proximal Transcription at Protein-Coding Genes. Mol Cell 2020; 76:738-752.e7. [PMID: 31809743 DOI: 10.1016/j.molcel.2019.10.034] [Citation(s) in RCA: 117] [Impact Index Per Article: 29.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2019] [Revised: 09/15/2019] [Accepted: 10/25/2019] [Indexed: 12/11/2022]
Abstract
The transition of RNA polymerase II (Pol II) from initiation to productive elongation is a central, regulated step in metazoan gene expression. At many genes, Pol II pauses stably in early elongation, remaining engaged with the 25- to 60-nt-long nascent RNA for many minutes while awaiting signals for release into the gene body. However, 15%-20% of genes display highly unstable promoter Pol II, suggesting that paused polymerase might dissociate from template DNA at these promoters and release a short, non-productive mRNA. Here, we report that paused Pol II can be actively destabilized by the Integrator complex. Specifically, we present evidence that Integrator utilizes its RNA endonuclease activity to cleave nascent RNA and drive termination of paused Pol II. These findings uncover a previously unappreciated mechanism of metazoan gene repression, akin to bacterial transcription attenuation, wherein promoter-proximal Pol II is prevented from entering productive elongation through factor-regulated termination.
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Affiliation(s)
- Nathan D Elrod
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch at Galveston, Galveston, TX 77550, USA
| | - Telmo Henriques
- Department of Biological Chemistry and Molecular Pharmacology, Blavatnik Institute, Harvard Medical School, Boston, MA 02115, USA
| | - Kai-Lieh Huang
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch at Galveston, Galveston, TX 77550, USA
| | - Deirdre C Tatomer
- Department of Biochemistry and Biophysics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Jeremy E Wilusz
- Department of Biochemistry and Biophysics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Eric J Wagner
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch at Galveston, Galveston, TX 77550, USA.
| | - Karen Adelman
- Department of Biological Chemistry and Molecular Pharmacology, Blavatnik Institute, Harvard Medical School, Boston, MA 02115, USA.
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56
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Meiotic gene silencing complex MTREC/NURS recruits the nuclear exosome to YTH-RNA-binding protein Mmi1. PLoS Genet 2020; 16:e1008598. [PMID: 32012158 PMCID: PMC7018101 DOI: 10.1371/journal.pgen.1008598] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2019] [Revised: 02/13/2020] [Accepted: 01/03/2020] [Indexed: 11/24/2022] Open
Abstract
Accurate target recognition in transcript degradation is crucial for regulation of gene expression. In the fission yeast Schizosaccharomyces pombe, a number of meiotic transcripts are recognized by a YTH-family RNA-binding protein, Mmi1, and selectively degraded by the nuclear exosome during mitotic growth. Mmi1 forms nuclear foci in mitotically growing cells, and the nuclear exosome colocalizes to such foci. However, it remains elusive how Mmi1 and the nuclear exosome are connected. Here, we show that a complex called MTREC (Mtl1-Red1 core) or NURS (nuclear RNA silencing) that consists of a zinc-finger protein, Red1, and an RNA helicase, Mtl1, is required for the recruitment of the nuclear exosome to Mmi1 foci. Physical interaction between Mmi1 and the nuclear exosome depends on Red1. Furthermore, a chimeric protein involving Mmi1 and Rrp6, which is a nuclear-specific component of the exosome, suppresses the ectopic expression phenotype of meiotic transcripts in red1Δ cells and mtl1 mutant cells. These data indicate that the primary function of MTREC/NURS in meiotic transcript elimination is to link Mmi1 to the nuclear exosome physically. Since abnormal gene expression is detrimental to proliferation, cells possess a number of mechanisms to regulate gene expression at transcriptional and post-transcriptional levels. In particular, expression of meiotic genes is rigorously repressed in somatic cells because their aberrant expression causes severe cellular defects including genome instability and tumorigenesis. In the fission yeast Schizosaccharomyces pombe, selective degradation of meiotic transcripts is employed to prevent their deleterious expression during mitotic growth. Meiotic transcripts are recognized by a YTH-family RNA-binding protein, Mmi1. Mmi1 then induces their selective degradation by the nuclear exosome, which is a highly conserved exonuclease complex. However, little is known how Mmi1 cooperates with the nuclear exosome. Here, we demonstrate that the interaction of Mmi1 with the nuclear exosome is mediated by a complex termed MTREC/NURS that is composed of a conserved zinc-finger protein, Red1, and an RNA helicase, Mtl1. Our findings shed light on the target recognition mechanisms of post-transcriptional regulation.
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57
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Oh JM, Venters CC, Di C, Pinto AM, Wan L, Younis I, Cai Z, Arai C, So BR, Duan J, Dreyfuss G. U1 snRNP regulates cancer cell migration and invasion in vitro. Nat Commun 2020; 11:1. [PMID: 31911652 PMCID: PMC6946686 DOI: 10.1038/s41467-019-13993-7] [Citation(s) in RCA: 3113] [Impact Index Per Article: 778.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Accepted: 12/11/2019] [Indexed: 02/06/2023] Open
Abstract
Stimulated cells and cancer cells have widespread shortening of mRNA 3'-untranslated regions (3'UTRs) and switches to shorter mRNA isoforms due to usage of more proximal polyadenylation signals (PASs) in introns and last exons. U1 snRNP (U1), vertebrates' most abundant non-coding (spliceosomal) small nuclear RNA, silences proximal PASs and its inhibition with antisense morpholino oligonucleotides (U1 AMO) triggers widespread premature transcription termination and mRNA shortening. Here we show that low U1 AMO doses increase cancer cells' migration and invasion in vitro by up to 500%, whereas U1 over-expression has the opposite effect. In addition to 3'UTR length, numerous transcriptome changes that could contribute to this phenotype are observed, including alternative splicing, and mRNA expression levels of proto-oncogenes and tumor suppressors. These findings reveal an unexpected role for U1 homeostasis (available U1 relative to transcription) in oncogenic and activated cell states, and suggest U1 as a potential target for their modulation.
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Affiliation(s)
- Jung-Min Oh
- Howard Hughes Medical Institute, Department of Biochemistry and Biophysics, University of Pennsylvania School of Medicine, Philadelphia, PA, 19104-6148, USA
| | - Christopher C Venters
- Howard Hughes Medical Institute, Department of Biochemistry and Biophysics, University of Pennsylvania School of Medicine, Philadelphia, PA, 19104-6148, USA
| | - Chao Di
- Howard Hughes Medical Institute, Department of Biochemistry and Biophysics, University of Pennsylvania School of Medicine, Philadelphia, PA, 19104-6148, USA
| | - Anna Maria Pinto
- Howard Hughes Medical Institute, Department of Biochemistry and Biophysics, University of Pennsylvania School of Medicine, Philadelphia, PA, 19104-6148, USA
| | - Lili Wan
- Howard Hughes Medical Institute, Department of Biochemistry and Biophysics, University of Pennsylvania School of Medicine, Philadelphia, PA, 19104-6148, USA
| | - Ihab Younis
- Howard Hughes Medical Institute, Department of Biochemistry and Biophysics, University of Pennsylvania School of Medicine, Philadelphia, PA, 19104-6148, USA
| | - Zhiqiang Cai
- Howard Hughes Medical Institute, Department of Biochemistry and Biophysics, University of Pennsylvania School of Medicine, Philadelphia, PA, 19104-6148, USA
| | - Chie Arai
- Howard Hughes Medical Institute, Department of Biochemistry and Biophysics, University of Pennsylvania School of Medicine, Philadelphia, PA, 19104-6148, USA
| | - Byung Ran So
- Howard Hughes Medical Institute, Department of Biochemistry and Biophysics, University of Pennsylvania School of Medicine, Philadelphia, PA, 19104-6148, USA
| | - Jingqi Duan
- Howard Hughes Medical Institute, Department of Biochemistry and Biophysics, University of Pennsylvania School of Medicine, Philadelphia, PA, 19104-6148, USA
| | - Gideon Dreyfuss
- Howard Hughes Medical Institute, Department of Biochemistry and Biophysics, University of Pennsylvania School of Medicine, Philadelphia, PA, 19104-6148, USA.
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58
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Abstract
The RNA exosome is a ribonucleolytic multiprotein complex that is conserved and essential in all eukaryotes. Although we tend to speak of "the" exosome complex, it should be more correctly viewed as several different subtypes that share a common core. Subtypes of the exosome complex are present in the cytoplasm, the nucleus and the nucleolus of all eukaryotic cells, and carry out the 3'-5' processing and/or degradation of a wide range of RNA substrates.Because the substrate specificity of the exosome complex is determined by cofactors, the system is highly adaptable, and different organisms have adjusted the machinery to their specific needs. Here, we present an overview of exosome complexes and their cofactors that have been described in different eukaryotes.
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Affiliation(s)
- Cornelia Kilchert
- Institut für Biochemie, Justus-Liebig-Universität Gießen, Gießen, Germany.
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59
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Lloret-Llinares M, Jensen TH. Global Identification of Human Exosome Substrates Using RNA Interference and RNA Sequencing. Methods Mol Biol 2020; 2062:127-145. [PMID: 31768975 DOI: 10.1007/978-1-4939-9822-7_7] [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] [Indexed: 10/18/2023]
Abstract
The RNA exosome is involved in RNA processing and quality control. In humans, it consists of an enzymatically inactive nine-subunit core, with ribonucleolytic activity contributed by one or two additional components. Moreover, several protein cofactors interact with the exosome to enable and specify its recruitment to a wide range of substrates. A common strategy to identify these substrates has been to deplete an exosome subunit or a cofactor and subsequently interrogate which transcripts become stabilized. Here, we describe an experimental pipeline including siRNA-mediated depletion of the RNA exosome or its cofactors in HeLa cells, confirmation of the knockdown efficiencies, and the manual or high-throughput identification of exosome targets.
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Affiliation(s)
| | - Torben Heick Jensen
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark.
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60
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Winczura K, Domanski M, LaCava J. Affinity Proteomic Analysis of the Human Exosome and Its Cofactor Complexes. Methods Mol Biol 2020; 2062:291-325. [PMID: 31768983 DOI: 10.1007/978-1-4939-9822-7_15] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
In humans, the RNA exosome consists of an enzymatically inactive nine-subunit core, with ribonucleolytic activity contributed by additional components. Several cofactor complexes also interact with the exosome-these enable the recruitment of, and specify the activity upon, diverse substrates. Affinity capture coupled with mass spectrometry has proven to be an effective means to identify the compositions of RNA exosomes and their cofactor complexes: here, we describe a general experimental strategy for proteomic characterization of macromolecular complexes, applied to the exosome and an affiliated adapter protein, ZC3H18.
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Affiliation(s)
- Kinga Winczura
- School of Biosciences, College of Life and Environmental Sciences, University of Birmingham, Birmingham, UK
| | - Michal Domanski
- Department of Chemistry and Biochemistry, University of Bern, Bern, Switzerland
| | - John LaCava
- Laboratory of Cellular and Structural Biology, The Rockefeller University, New York, NY, USA.
- European Research Institute for the Biology of Ageing, University Medical Center Groningen, Groningen, AV, The Netherlands.
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61
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Elrod ND, Henriques T, Huang KL, Tatomer DC, Wilusz JE, Wagner EJ, Adelman K. The Integrator Complex Attenuates Promoter-Proximal Transcription at Protein-Coding Genes. Mol Cell 2019; 76:738-752.e7. [PMID: 31809743 DOI: 10.1101/725507] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2019] [Revised: 09/15/2019] [Accepted: 10/25/2019] [Indexed: 05/27/2023]
Abstract
The transition of RNA polymerase II (Pol II) from initiation to productive elongation is a central, regulated step in metazoan gene expression. At many genes, Pol II pauses stably in early elongation, remaining engaged with the 25- to 60-nt-long nascent RNA for many minutes while awaiting signals for release into the gene body. However, 15%-20% of genes display highly unstable promoter Pol II, suggesting that paused polymerase might dissociate from template DNA at these promoters and release a short, non-productive mRNA. Here, we report that paused Pol II can be actively destabilized by the Integrator complex. Specifically, we present evidence that Integrator utilizes its RNA endonuclease activity to cleave nascent RNA and drive termination of paused Pol II. These findings uncover a previously unappreciated mechanism of metazoan gene repression, akin to bacterial transcription attenuation, wherein promoter-proximal Pol II is prevented from entering productive elongation through factor-regulated termination.
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Affiliation(s)
- Nathan D Elrod
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch at Galveston, Galveston, TX 77550, USA
| | - Telmo Henriques
- Department of Biological Chemistry and Molecular Pharmacology, Blavatnik Institute, Harvard Medical School, Boston, MA 02115, USA
| | - Kai-Lieh Huang
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch at Galveston, Galveston, TX 77550, USA
| | - Deirdre C Tatomer
- Department of Biochemistry and Biophysics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Jeremy E Wilusz
- Department of Biochemistry and Biophysics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Eric J Wagner
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch at Galveston, Galveston, TX 77550, USA.
| | - Karen Adelman
- Department of Biological Chemistry and Molecular Pharmacology, Blavatnik Institute, Harvard Medical School, Boston, MA 02115, USA.
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62
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Silla T, Karadoulama E, Mąkosa D, Lubas M, Jensen TH. The RNA Exosome Adaptor ZFC3H1 Functionally Competes with Nuclear Export Activity to Retain Target Transcripts. Cell Rep 2019; 23:2199-2210. [PMID: 29768216 PMCID: PMC5972229 DOI: 10.1016/j.celrep.2018.04.061] [Citation(s) in RCA: 51] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2018] [Revised: 03/28/2018] [Accepted: 04/15/2018] [Indexed: 12/31/2022] Open
Abstract
Mammalian genomes are promiscuously transcribed, yielding protein-coding and non-coding products. Many transcripts are short lived due to their nuclear degradation by the ribonucleolytic RNA exosome. Here, we show that abolished nuclear exosome function causes the formation of distinct nuclear foci, containing polyadenylated (pA+) RNA secluded from nucleocytoplasmic export. We asked whether exosome co-factors could serve such nuclear retention. Co-localization studies revealed the enrichment of pA+ RNA foci with “pA-tail exosome targeting (PAXT) connection” components MTR4, ZFC3H1, and PABPN1 but no overlap with known nuclear structures such as Cajal bodies, speckles, paraspeckles, or nucleoli. Interestingly, ZFC3H1 is required for foci formation, and in its absence, selected pA+ RNAs, including coding and non-coding transcripts, are exported to the cytoplasm in a process dependent on the mRNA export factor AlyREF. Our results establish ZFC3H1 as a central nuclear pA+ RNA retention factor, counteracting nuclear export activity. Abolished RNA exosome function leads to pA+ RNA accumulation in nuclear foci pA+ RNA foci are enriched with various transcripts and exosome adaptor proteins The exosome adaptor protein ZFC3H1 is required for pA+ RNA foci formation ZFC3H1 functionally counteracts the mRNA export factor AlyREF
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Affiliation(s)
- Toomas Silla
- Department of Molecular Biology and Genetics, Aarhus University, C.F. Møllers Allé 3, Building 1130, 8000 Aarhus C, Denmark
| | - Evdoxia Karadoulama
- Department of Molecular Biology and Genetics, Aarhus University, C.F. Møllers Allé 3, Building 1130, 8000 Aarhus C, Denmark; The Bioinformatics Centre, Department of Biology and Biotech Research and Innovation Centre, University of Copenhagen, Ole Maaloesvej 5, 2200 Copenhagen, Denmark
| | - Dawid Mąkosa
- Department of Molecular Biology and Genetics, Aarhus University, C.F. Møllers Allé 3, Building 1130, 8000 Aarhus C, Denmark
| | - Michal Lubas
- Department of Molecular Biology and Genetics, Aarhus University, C.F. Møllers Allé 3, Building 1130, 8000 Aarhus C, Denmark
| | - Torben Heick Jensen
- Department of Molecular Biology and Genetics, Aarhus University, C.F. Møllers Allé 3, Building 1130, 8000 Aarhus C, Denmark.
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63
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Abstract
The numerous quality control pathways that target defective ribonucleic acids (RNAs) for degradation play key roles in shaping mammalian transcriptomes and preventing disease. These pathways monitor most steps in the biogenesis of both noncoding RNAs (ncRNAs) and protein-coding messenger RNAs (mRNAs), degrading ncRNAs that fail to form functional complexes with one or more proteins and eliminating mRNAs that encode abnormal, potentially toxic proteins. Mutations in components of diverse RNA surveillance pathways manifest as disease. Some mutations are characterized by increased interferon production, suggesting that a major role of these pathways is to prevent aberrant cellular RNAs from being recognized as "non-self." Other mutations are common in cancer, or result in developmental defects, revealing the importance of RNA surveillance to cell and organismal function.
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Affiliation(s)
- Sandra L Wolin
- RNA Biology Laboratory, Center for Cancer Research, National Cancer Institute, Frederick, MD 21702, USA.
| | - Lynne E Maquat
- Department of Biochemistry and Biophysics, School of Medicine and Dentistry, University of Rochester, Rochester, NY 14642, USA.
- Center for RNA Biology, University of Rochester, Rochester, NY 14642, USA
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64
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Lange H, Ndecky SYA, Gomez-Diaz C, Pflieger D, Butel N, Zumsteg J, Kuhn L, Piermaria C, Chicher J, Christie M, Karaaslan ES, Lang PLM, Weigel D, Vaucheret H, Hammann P, Gagliardi D. RST1 and RIPR connect the cytosolic RNA exosome to the Ski complex in Arabidopsis. Nat Commun 2019; 10:3871. [PMID: 31455787 PMCID: PMC6711988 DOI: 10.1038/s41467-019-11807-4] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2019] [Accepted: 08/05/2019] [Indexed: 02/01/2023] Open
Abstract
The RNA exosome is a key 3’−5’ exoribonuclease with an evolutionarily conserved structure and function. Its cytosolic functions require the co-factors SKI7 and the Ski complex. Here we demonstrate by co-purification experiments that the ARM-repeat protein RESURRECTION1 (RST1) and RST1 INTERACTING PROTEIN (RIPR) connect the cytosolic Arabidopsis RNA exosome to the Ski complex. rst1 and ripr mutants accumulate RNA quality control siRNAs (rqc-siRNAs) produced by the post-transcriptional gene silencing (PTGS) machinery when mRNA degradation is compromised. The small RNA populations observed in rst1 and ripr mutants are also detected in mutants lacking the RRP45B/CER7 core exosome subunit. Thus, molecular and genetic evidence supports a physical and functional link between RST1, RIPR and the RNA exosome. Our data reveal the existence of additional cytosolic exosome co-factors besides the known Ski subunits. RST1 is not restricted to plants, as homologues with a similar domain architecture but unknown function exist in animals, including humans. Cytosolic RNA degradation by the RNA exosome requires the Ski complex. Here the authors show that the proteins RST1 and RIPR assist the RNA exosome and the Ski complex in RNA degradation, thereby preventing the production of secondary siRNAs from endogenous mRNAs.
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Affiliation(s)
- Heike Lange
- Institut de biologie moléculaire des plantes, CNRS, Université de Strasbourg, Strasbourg, France.
| | - Simon Y A Ndecky
- Institut de biologie moléculaire des plantes, CNRS, Université de Strasbourg, Strasbourg, France
| | - Carlos Gomez-Diaz
- Institut de biologie moléculaire des plantes, CNRS, Université de Strasbourg, Strasbourg, France
| | - David Pflieger
- Institut de biologie moléculaire des plantes, CNRS, Université de Strasbourg, Strasbourg, France
| | - Nicolas Butel
- Institut Jean-Pierre Bourgin, INRA, AgroParisTech, CNRS, Université Paris-Saclay, Versailles, France
| | - Julie Zumsteg
- Institut de biologie moléculaire des plantes, CNRS, Université de Strasbourg, Strasbourg, France
| | - Lauriane Kuhn
- Plateforme protéomique Strasbourg Esplanade FR1589 du CNRS, Université de Strasbourg, Strasbourg, France
| | - Christina Piermaria
- Plateforme protéomique Strasbourg Esplanade FR1589 du CNRS, Université de Strasbourg, Strasbourg, France
| | - Johana Chicher
- Plateforme protéomique Strasbourg Esplanade FR1589 du CNRS, Université de Strasbourg, Strasbourg, France
| | - Michael Christie
- Max Planck Institute for Developmental Biology, Tübingen, Germany
| | - Ezgi S Karaaslan
- Max Planck Institute for Developmental Biology, Tübingen, Germany
| | | | - Detlef Weigel
- Max Planck Institute for Developmental Biology, Tübingen, Germany
| | - Hervé Vaucheret
- Institut Jean-Pierre Bourgin, INRA, AgroParisTech, CNRS, Université Paris-Saclay, Versailles, France
| | - Philippe Hammann
- Plateforme protéomique Strasbourg Esplanade FR1589 du CNRS, Université de Strasbourg, Strasbourg, France
| | - Dominique Gagliardi
- Institut de biologie moléculaire des plantes, CNRS, Université de Strasbourg, Strasbourg, France.
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65
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Lingaraju M, Johnsen D, Schlundt A, Langer LM, Basquin J, Sattler M, Heick Jensen T, Falk S, Conti E. The MTR4 helicase recruits nuclear adaptors of the human RNA exosome using distinct arch-interacting motifs. Nat Commun 2019; 10:3393. [PMID: 31358741 PMCID: PMC6662825 DOI: 10.1038/s41467-019-11339-x] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2019] [Accepted: 07/07/2019] [Indexed: 12/16/2022] Open
Abstract
The nuclear exosome and its essential co-factor, the RNA helicase MTR4, play crucial roles in several RNA degradation pathways. Besides unwinding RNA substrates for exosome-mediated degradation, MTR4 associates with RNA-binding proteins that function as adaptors in different RNA processing and decay pathways. Here, we identify and characterize the interactions of human MTR4 with a ribosome processing adaptor, NVL, and with ZCCHC8, an adaptor involved in the decay of small nuclear RNAs. We show that the unstructured regions of NVL and ZCCHC8 contain short linear motifs that bind the MTR4 arch domain in a mutually exclusive manner. These short sequences diverged from the arch-interacting motif (AIM) of yeast rRNA processing factors. Our results suggest that nuclear exosome adaptors have evolved canonical and non-canonical AIM sequences to target human MTR4 and demonstrate the versatility and specificity with which the MTR4 arch domain can recruit a repertoire of different RNA-binding proteins.
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Affiliation(s)
- Mahesh Lingaraju
- Department of Structural Cell Biology, Max-Planck-Institute of Biochemistry, Am Klopferspitz 18, D-82152, Martinsried, Germany
| | - Dennis Johnsen
- Department of Molecular Biology and Genetics, Aarhus University, C.F. Møllers Alle 3, 8000, Aarhus C, Denmark
| | - Andreas Schlundt
- Center for Integrated Protein Science Munich (CIPSM) at Department of Chemistry, Technical University of Munich (TUM), 85747, Garching, Germany.,Institute of Structural Biology, Helmholtz-Zentrum München, 85764, Neuherberg, Germany.,Institute for Molecular Biosciences and Center for Biomolecular Magnetic Resonance (BMRZ) at Johann Wolfgang Goethe-University, Frankfurt am Main, 60438, Germany
| | - Lukas M Langer
- Department of Structural Cell Biology, Max-Planck-Institute of Biochemistry, Am Klopferspitz 18, D-82152, Martinsried, Germany
| | - Jérôme Basquin
- Department of Structural Cell Biology, Max-Planck-Institute of Biochemistry, Am Klopferspitz 18, D-82152, Martinsried, Germany
| | - Michael Sattler
- Center for Integrated Protein Science Munich (CIPSM) at Department of Chemistry, Technical University of Munich (TUM), 85747, Garching, Germany.,Institute of Structural Biology, Helmholtz-Zentrum München, 85764, Neuherberg, Germany
| | - Torben Heick Jensen
- Department of Molecular Biology and Genetics, Aarhus University, C.F. Møllers Alle 3, 8000, Aarhus C, Denmark
| | - Sebastian Falk
- Department of Structural Cell Biology, Max-Planck-Institute of Biochemistry, Am Klopferspitz 18, D-82152, Martinsried, Germany. .,Max F. Perutz Laboratories, Department of Structural and Computational Biology, University of Vienna, Campus Vienna Biocenter 5, 1030, Vienna, Austria.
| | - Elena Conti
- Department of Structural Cell Biology, Max-Planck-Institute of Biochemistry, Am Klopferspitz 18, D-82152, Martinsried, Germany.
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66
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Fan J, Kuai B, Wang K, Wang L, Wang Y, Wu X, Chi B, Li G, Cheng H. mRNAs are sorted for export or degradation before passing through nuclear speckles. Nucleic Acids Res 2019; 46:8404-8416. [PMID: 30032211 PMCID: PMC6144872 DOI: 10.1093/nar/gky650] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2018] [Accepted: 07/10/2018] [Indexed: 12/14/2022] Open
Abstract
A significant fraction of mRNAs are degraded by the nuclear exosome in normal cells. Here, we studied where and when these exosome target mRNAs are sorted away from properly exported ones in the cells. We show that upon exosome inactivation, polyA RNAs are apparently accumulated in nuclear foci that are distinct from nuclear speckles (NSs), and provide several lines of evidence supporting that these polyA RNAs mainly correspond to accumulating exosome target mRNAs. These results suggest that exosomal mRNA degradation mostly occurs outside of NSs. In support of this possibility, targeting exosome target mRNAs to NSs stabilizes them by preventing exosomal degradation. Furthermore, inhibiting mRNA release from NSs does not attenuate exosomal degradation in normal cells, and results in polyA RNA accumulation both inside and outside of NSs in exosome inactivated cells, suggesting that passage through NSs is not required for sorting mRNAs for degradation or export. Indeed, exosome target mRNAs that normally do not enter NSs are exported upon exosome inactivation. Together, our data suggest that exosome target mRNAs are mainly degraded in the nucleoplasm before entering NSs and rapid removal of these mRNAs is important for preventing their nuclear export.
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Affiliation(s)
- Jing Fan
- State Key Laboratory of Molecular Biology, Shanghai Key Laboratory of Molecular Andrology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Bin Kuai
- State Key Laboratory of Molecular Biology, Shanghai Key Laboratory of Molecular Andrology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Ke Wang
- State Key Laboratory of Molecular Biology, Shanghai Key Laboratory of Molecular Andrology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Lantian Wang
- State Key Laboratory of Molecular Biology, Shanghai Key Laboratory of Molecular Andrology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Yimin Wang
- State Key Laboratory of Molecular Biology, Shanghai Key Laboratory of Molecular Andrology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Xudong Wu
- Laboratory of Molecular Modeling and Design, State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
| | - Binkai Chi
- State Key Laboratory of Molecular Biology, Shanghai Key Laboratory of Molecular Andrology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Guohui Li
- Laboratory of Molecular Modeling and Design, State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
| | - Hong Cheng
- State Key Laboratory of Molecular Biology, Shanghai Key Laboratory of Molecular Andrology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai 200031, China
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67
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Helicase-Dependent RNA Decay Illuminated by a Cryo-EM Structure of a Human Nuclear RNA Exosome-MTR4 Complex. Cell 2019; 173:1663-1677.e21. [PMID: 29906447 DOI: 10.1016/j.cell.2018.05.041] [Citation(s) in RCA: 98] [Impact Index Per Article: 19.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2018] [Revised: 04/26/2018] [Accepted: 05/17/2018] [Indexed: 01/08/2023]
Abstract
The ribonucleolytic RNA exosome interacts with RNA helicases to degrade RNA. To understand how the 3' to 5' Mtr4 helicase engages RNA and the nuclear exosome, we reconstituted 14-subunit Mtr4-containing RNA exosomes from Saccharomyces cerevisiae, Schizosaccharomyces pombe, and human and show that they unwind structured substrates to promote degradation. We loaded a human exosome with an optimized DNA-RNA chimera that stalls MTR4 during unwinding and determined its structure to an overall resolution of 3.45 Å by cryoelectron microscopy (cryo-EM). The structure reveals an RNA-engaged helicase atop the non-catalytic core, with RNA captured within the central channel and DIS3 exoribonuclease active site. MPP6 tethers MTR4 to the exosome through contacts to the RecA domains of MTR4. EXOSC10 remains bound to the core, but its catalytic module and cofactor C1D are displaced by RNA-engaged MTR4. Competition for the exosome core may ensure that RNA is committed to degradation by DIS3 when engaged by MTR4.
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68
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Wang J, Chen J, Wu G, Zhang H, Du X, Chen S, Zhang L, Wang K, Fan J, Gao S, Wu X, Zhang S, Kuai B, Zhao P, Chi B, Wang L, Li G, Wong CCL, Zhou Y, Li J, Yun C, Cheng H. NRDE2 negatively regulates exosome functions by inhibiting MTR4 recruitment and exosome interaction. Genes Dev 2019; 33:536-549. [PMID: 30842217 PMCID: PMC6499326 DOI: 10.1101/gad.322602.118] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2018] [Accepted: 02/05/2019] [Indexed: 12/28/2022]
Abstract
The exosome functions in the degradation of diverse RNA species, yet how it is negatively regulated remains largely unknown. Here, we show that NRDE2 forms a 1:1 complex with MTR4, a nuclear exosome cofactor critical for exosome recruitment, via a conserved MTR4-interacting domain (MID). Unexpectedly, NRDE2 mainly localizes in nuclear speckles, where it inhibits MTR4 recruitment and RNA degradation, and thereby ensures efficient mRNA nuclear export. Structural and biochemical data revealed that NRDE2 interacts with MTR4's key residues, locks MTR4 in a closed conformation, and inhibits MTR4 interaction with the exosome as well as proteins important for MTR4 recruitment, such as the cap-binding complex (CBC) and ZFC3H1. Functionally, MID deletion results in the loss of self-renewal of mouse embryonic stem cells. Together, our data pinpoint NRDE2 as a nuclear exosome negative regulator that ensures mRNA stability and nuclear export.
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Affiliation(s)
- Jianshu Wang
- State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai 200031, China.,Shanghai Key Laboratory of Molecular Andrology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai 200031, China
| | - Jiyun Chen
- Department of Biophysics, Beijing Key Laboratory of Tumor Systems Biology, School of Basic Medical Sciences, Peking University Health Science Center, Beijing 100191, China
| | - Guifen Wu
- State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai 200031, China.,Shanghai Key Laboratory of Molecular Andrology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai 200031, China
| | - Hongling Zhang
- Shanghai Key Laboratory of Molecular Andrology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai 200031, China.,State Key Laboratory of Cell Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai 200031, China
| | - Xian Du
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Suli Chen
- State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai 200031, China.,Shanghai Key Laboratory of Molecular Andrology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai 200031, China
| | - Li Zhang
- State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai 200031, China.,Shanghai Key Laboratory of Molecular Andrology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai 200031, China
| | - Ke Wang
- State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai 200031, China.,Shanghai Key Laboratory of Molecular Andrology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai 200031, China
| | - Jing Fan
- State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai 200031, China.,Shanghai Key Laboratory of Molecular Andrology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai 200031, China
| | - Shuaixin Gao
- Center for Precision Medicine Multi-Omics Research, Peking University Health Science Center, Beijing 100191, China
| | - Xudong Wu
- Laboratory of Molecular Modeling and Design, State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
| | - Shouxiang Zhang
- Department of Biophysics, Beijing Key Laboratory of Tumor Systems Biology, School of Basic Medical Sciences, Peking University Health Science Center, Beijing 100191, China
| | - Bin Kuai
- State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai 200031, China.,Shanghai Key Laboratory of Molecular Andrology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai 200031, China
| | - Peng Zhao
- Department of Biophysics, Beijing Key Laboratory of Tumor Systems Biology, School of Basic Medical Sciences, Peking University Health Science Center, Beijing 100191, China
| | - Binkai Chi
- State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai 200031, China.,Shanghai Key Laboratory of Molecular Andrology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai 200031, China
| | - Lantian Wang
- State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai 200031, China.,Shanghai Key Laboratory of Molecular Andrology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai 200031, China
| | - Guohui Li
- Laboratory of Molecular Modeling and Design, State Key Laboratory of Molecular Reaction Dynamics, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, China
| | - Catherine C L Wong
- Center for Precision Medicine Multi-Omics Research, Peking University Health Science Center, Beijing 100191, China.,State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, Beijing 100191, China
| | - Yu Zhou
- Hubei Key Laboratory of Cell Homeostasis, College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Jinsong Li
- Shanghai Key Laboratory of Molecular Andrology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai 200031, China.,State Key Laboratory of Cell Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai 200031, China
| | - Caihong Yun
- Department of Biophysics, Beijing Key Laboratory of Tumor Systems Biology, School of Basic Medical Sciences, Peking University Health Science Center, Beijing 100191, China
| | - Hong Cheng
- State Key Laboratory of Molecular Biology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai 200031, China.,Shanghai Key Laboratory of Molecular Andrology, CAS Center for Excellence in Molecular Cell Science, Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, University of Chinese Academy of Sciences, Shanghai 200031, China
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69
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Jiao AL, Perales R, Umbreit NT, Haswell JR, Piper ME, Adams BD, Pellman D, Kennedy S, Slack FJ. Human nuclear RNAi-defective 2 (NRDE2) is an essential RNA splicing factor. RNA (NEW YORK, N.Y.) 2019; 25:352-363. [PMID: 30538148 PMCID: PMC6380277 DOI: 10.1261/rna.069773.118] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2018] [Accepted: 12/20/2018] [Indexed: 05/05/2023]
Abstract
The accurate inheritance of genetic material is a basic necessity in all domains of life and an unexpectedly large number of RNA processing factors are required for mitotic progression and genome stability. NRDE2 (nuclear RNAi defective-2) is an evolutionarily conserved protein originally discovered for its role in nuclear RNA interference (RNAi) and heritable gene silencing in Caenorhabditis elegans (C. elegans). The function of the human NRDE2 gene remains poorly understood. Here we show that human NRDE2 is an essential protein required for suppressing intron retention in a subset of pre-mRNAs containing short, GC-rich introns with relatively weak 5' and 3' splice sites. NRDE2 preferentially interacts with components of the U5 small nuclear ribonucleoprotein (snRNP), the exon junction complex, and the RNA exosome. Interestingly, NRDE2-depleted cells exhibit greatly increased levels of genomic instability and DNA damage, as well as defects in centrosome maturation and mitotic progression. We identify the essential centriolar satellite protein, CEP131, as a direct NRDE2-regulated target. NRDE2 specifically binds to and promotes the efficient splicing of CEP131 pre-mRNA, and depleting NRDE2 dramatically reduces CEP131 protein expression, contributing to impaired recruitment of critical centrosomal proteins (e.g., γ-tubulin and Aurora Kinase A) to the spindle poles during mitosis. Our work establishes a conserved role for human NRDE2 in RNA splicing, characterizes the severe genomic instability phenotypes observed upon loss of NRDE2, and highlights the direct regulation of CEP131 splicing as one of multiple mechanisms through which such phenotypes might be explained.
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Affiliation(s)
- Alan L Jiao
- HMS Initiative for RNA Medicine, Department of Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts 02215, USA
- Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, Connecticut 06511, USA
| | - Roberto Perales
- Department of Genetics, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Neil T Umbreit
- Department of Cell Biology, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Jeffrey R Haswell
- HMS Initiative for RNA Medicine, Department of Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts 02215, USA
- Department of Biological and Biomedical Sciences, Harvard University, Boston, Massachusetts 02115, USA
| | - Mary E Piper
- Department of Biostatistics, Harvard T.H. Chan School of Public Health, Boston, Massachusetts 02115, USA
| | - Brian D Adams
- HMS Initiative for RNA Medicine, Department of Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts 02215, USA
| | - David Pellman
- Department of Cell Biology, Harvard Medical School, Boston, Massachusetts 02115, USA
- Department of Pediatric Oncology, Dana-Farber Cancer Institute and Pediatric Hematology/Oncology, Boston Children's Hospital, Boston, Massachusetts 02215, USA
- Howard Hughes Medical Institute, Chevy Chase, Maryland 20815, USA
| | - Scott Kennedy
- Department of Genetics, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Frank J Slack
- HMS Initiative for RNA Medicine, Department of Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts 02215, USA
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70
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Ruiz JC, Hunter OV, Conrad NK. Kaposi's sarcoma-associated herpesvirus ORF57 protein protects viral transcripts from specific nuclear RNA decay pathways by preventing hMTR4 recruitment. PLoS Pathog 2019; 15:e1007596. [PMID: 30785952 PMCID: PMC6398867 DOI: 10.1371/journal.ppat.1007596] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2018] [Revised: 03/04/2019] [Accepted: 01/25/2019] [Indexed: 12/15/2022] Open
Abstract
Nuclear RNAs are subject to a number of RNA decay pathways that serve quality control and regulatory functions. As a result, any virus that expresses its genes in the nucleus must have evolved mechanisms that avoid these pathways, but the how viruses evade nuclear RNA decay remains largely unknown. The multifunctional Kaposi’s sarcoma-associated herpesvirus (KSHV) ORF57 (Mta) protein is required for the nuclear stability of viral transcripts. In the absence of ORF57, we show that viral transcripts are subject to degradation by two specific nuclear RNA decay pathways, PABPN1 and PAPα/γ-mediated RNA decay (PPD) in which decay factors are recruited through poly(A) tails, and an ARS2-mediated RNA decay pathway dependent on the 5ʹ RNA cap. In transcription pulse chase assays, ORF57 appears to act primarily by inhibiting the ARS2-mediated RNA decay pathway. In the context of viral infection in cultured cells, inactivation of both decay pathways by RNAi is necessary for the restoration of ORF57-dependent viral genes produced from an ORF57-null bacmid. Mechanistically, we demonstrate that ORF57 protects viral transcripts by preventing the recruitment of the exosome co-factor hMTR4. In addition, our data suggest that ORF57 recruitment of ALYREF inhibits hMTR4 association with some viral RNAs, whereas other KSHV transcripts are stabilized by ORF57 in an ALYREF-independent fashion. In conclusion, our studies show that KSHV RNAs are subject to nuclear degradation by two specific host pathways, PPD and ARS2-mediated decay, and ORF57 protects viral transcripts from decay by inhibiting hMTR4 recruitment. Eukaryotic cells contain numerous nuclear RNA quality control (QC) systems that ensure transcriptome fidelity by detecting and degrading aberrant RNAs. Some viral RNAs are also predicted to be degraded by these RNA QC systems, so viruses have evolved mechanisms that counter host RNA QC pathways. Previous studies showed that the Kaposi’s sarcoma-associated herpesvirus (KSHV) expresses the ORF57 protein to protect its RNAs from nuclear decay. However, neither the specific host pathways that degrade KSHV RNAs nor the mechanisms describing ORF57 protection of viral RNAs were known. Our data suggest that ORF57 protects viral RNAs from two different nuclear RNA QC pathways, PABPN1 and PAPα/γ-mediated RNA decay (PPD) and an ARS2-mediated RNA decay pathway. Mechanistically, we show that ORF57 binds directly to viral RNAs and prevents the recruitment of hMTR4, a cellular factor whose function is to recruit the exosome, the complex responsible for RNA decay, to the transcript. We conclude that by preventing hMTR4 recruitment, ORF57 protects viral RNAs from degradation resulting in robust expression of viral genes.
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Affiliation(s)
- Julio C. Ruiz
- Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Olga V. Hunter
- Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Nicholas K. Conrad
- Department of Microbiology, University of Texas Southwestern Medical Center, Dallas, Texas
- * E-mail:
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71
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Schmid M, Jensen TH. The Nuclear RNA Exosome and Its Cofactors. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1203:113-132. [PMID: 31811632 DOI: 10.1007/978-3-030-31434-7_4] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
The RNA exosome is a highly conserved ribonuclease endowed with 3'-5' exonuclease and endonuclease activities. The multisubunit complex resides in both the nucleus and the cytoplasm, with varying compositions and activities between the two compartments. While the cytoplasmic exosome functions mostly in mRNA quality control pathways, the nuclear RNA exosome partakes in the 3'-end processing and complete decay of a wide variety of substrates, including virtually all types of noncoding (nc) RNAs. To handle these diverse tasks, the nuclear exosome engages with dedicated cofactors, some of which serve as activators by stimulating decay through oligoA addition and/or RNA helicase activities or, as adaptors, by recruiting RNA substrates through their RNA-binding capacities. Most nuclear exosome cofactors contain the essential RNA helicase Mtr4 (MTR4 in humans). However, apart from Mtr4, nuclear exosome cofactors have undergone significant evolutionary divergence. Here, we summarize biochemical and functional knowledge about the nuclear exosome and exemplify its cofactor variety by discussing the best understood model organisms-the budding yeast Saccharomyces cerevisiae, the fission yeast Schizosaccharomyces pombe, and human cells.
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Affiliation(s)
- Manfred Schmid
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus C, Denmark
| | - Torben Heick Jensen
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus C, Denmark.
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72
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Escaping nuclear decay: the significance of mRNA export for gene expression. Curr Genet 2018; 65:473-476. [DOI: 10.1007/s00294-018-0913-x] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2018] [Revised: 11/24/2018] [Accepted: 11/28/2018] [Indexed: 12/12/2022]
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73
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Tudek A, Lloret-Llinares M, Jensen TH. The multitasking polyA tail: nuclear RNA maturation, degradation and export. Philos Trans R Soc Lond B Biol Sci 2018; 373:rstb.2018.0169. [PMID: 30397105 DOI: 10.1098/rstb.2018.0169] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/20/2018] [Indexed: 12/17/2022] Open
Abstract
A polyA (pA) tail is an essential modification added to the 3' ends of a wide range of RNAs at different stages of their metabolism. Here, we describe the main sources of polyadenylation and outline their underlying biochemical interactions within the nuclei of budding yeast Saccharomyces cerevisiae, human cells and, when relevant, the fission yeast Schizosaccharomyces pombe Polyadenylation mediated by the S. cerevisiae Trf4/5 enzymes, and their human homologues PAPD5/7, typically leads to the 3'-end trimming or complete decay of non-coding RNAs. By contrast, the primary function of canonical pA polymerases (PAPs) is to produce stable and nuclear export-competent mRNAs. However, this dichotomy is becoming increasingly blurred, at least in S. pombe and human cells, where polyadenylation mediated by canonical PAPs may also result in transcript decay.This article is part of the theme issue '5' and 3' modifications controlling RNA degradation'.
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Affiliation(s)
- Agnieszka Tudek
- Department of Molecular Biology and Genetics, Aarhus University, C. F. Møllers Allé 3, building 1130, 8000 Aarhus C, Denmark
| | - Marta Lloret-Llinares
- Department of Molecular Biology and Genetics, Aarhus University, C. F. Møllers Allé 3, building 1130, 8000 Aarhus C, Denmark
| | - Torben Heick Jensen
- Department of Molecular Biology and Genetics, Aarhus University, C. F. Møllers Allé 3, building 1130, 8000 Aarhus C, Denmark
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74
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Palazzo AF, Lee ES. Sequence Determinants for Nuclear Retention and Cytoplasmic Export of mRNAs and lncRNAs. Front Genet 2018; 9:440. [PMID: 30386371 PMCID: PMC6199362 DOI: 10.3389/fgene.2018.00440] [Citation(s) in RCA: 60] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2018] [Accepted: 09/14/2018] [Indexed: 11/26/2022] Open
Abstract
Eukaryotes are divided into two major compartments: the nucleus where RNA is synthesized and processed, and the cytoplasm, where mRNA is translated into proteins. Although many different RNAs are made, only a subset is allowed access to the cytoplasm, primarily RNAs involved in protein synthesis (mRNA, tRNA, and rRNA). In contrast, nuclear retained transcripts are mostly long non-coding RNAs (lncRNAs) whose role in cell physiology has been a source of much investigation in the past few years. In addition, it is likely that many non-functional RNAs, which arise by spurious transcription and misprocessing of functional RNAs, are also retained in the nucleus and degraded. In this review, the main sequence features that dictate whether any particular mRNA or lncRNA is a substrate for retention in the nucleus, or export to the cytoplasm, are discussed. Although nuclear export is promoted by RNA-splicing due to the fact that the spliceosome can help recruit export factors to the mature RNA, nuclear export does not require splicing. Indeed, most stable unspliced transcripts are well exported and associate with these same export factors in a splicing-independent manner. In contrast, nuclear retention is promoted by specialized cis-elements found in certain RNAs. This new understanding of the determinants of nuclear retention and cytoplasmic export provides a deeper understanding of how information flow is regulated in eukaryotic cells. Ultimately these processes promote the evolution of complexity in eukaryotes by shaping the genomic content through constructive neutral evolution.
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75
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Richard P, Ogami K, Chen Y, Feng S, Moresco JJ, Yates JR, Manley JL. NRDE-2, the human homolog of fission yeast Nrl1, prevents DNA damage accumulation in human cells. RNA Biol 2018; 15:868-876. [PMID: 29902117 DOI: 10.1080/15476286.2018.1467180] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The RNA helicase Mtr4 is a versatile protein that is a crucial component of several distinct RNA surveillance complexes. Here we describe a novel complex that contains Mtr4, but has a role distinct from any of those previously described. We found that Mtr4 association with the human homolog of fission yeast Nrl1, NRDE-2, defines a novel function for Mtr4 in the DNA damage response pathway. We provide biochemical evidence that Mtr4 and NRDE-2 are part of the same complex and show that both proteins play a role in the DNA damage response by maintaining low DNA double-strand break levels. Importantly, the DNA damage response function of the Mtr4/NRDE-2 complex does not depend on the formation of R loops. We show however that NRDE-2 and Mtr4 can affect R-loop signals at a subset of distinct genes, possibly regulating their expression. Our work not only expands the wide range of Mtr4 functions, but also elucidates an important role of the less characterized human NRDE-2 protein.
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Affiliation(s)
- Patricia Richard
- a Department of Biological Sciences , Columbia University , New York , NY , USA
| | - Koichi Ogami
- a Department of Biological Sciences , Columbia University , New York , NY , USA.,b Department of Biological Chemistry, Graduate School of Pharmaceutical Sciences , Nagoya City University , Nagoya , Japan
| | - Yaqiong Chen
- a Department of Biological Sciences , Columbia University , New York , NY , USA
| | - Shuang Feng
- a Department of Biological Sciences , Columbia University , New York , NY , USA
| | - James J Moresco
- c Department of Molecular Medicine , The Scripps Research Institute , La Jolla , CA , USA
| | - John R Yates
- c Department of Molecular Medicine , The Scripps Research Institute , La Jolla , CA , USA
| | - James L Manley
- a Department of Biological Sciences , Columbia University , New York , NY , USA
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76
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Structural basis for MTR4-ZCCHC8 interactions that stimulate the MTR4 helicase in the nuclear exosome-targeting complex. Proc Natl Acad Sci U S A 2018; 115:E5506-E5515. [PMID: 29844170 PMCID: PMC6004480 DOI: 10.1073/pnas.1803530115] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Aberrant or unwanted transcripts can be degraded by the RNA exosome with the help of the nuclear exosome-targeting (NEXT) complex. NEXT, composed of RNA-binding protein RBM7, scaffold ZCCHC8, and helicase MTR4, is implicated in stress response, neurodegeneration, and viral ribogenesis. Here, we characterize the activities of NEXT that support its role in exosome-mediated decay. NEXT catalyzes 3′→5′ helicase activity and disrupts RNA:RNA and DNA:RNA duplexes more efficiently than MTR4. Optimal activity is observed when substrates include a uridine-rich motif, for interactions with RBM7, and a 3′ poly(A) tail. The ZCCHC8 C-terminal domain binds the helicase core and can stimulate MTR4 helicase/ATPase activities. Our results highlight the interplay among NEXT subunits to ensure effective targeting of substrates. The nuclear exosome-targeting (NEXT) complex functions as an RNA exosome cofactor and is involved in surveillance and turnover of aberrant transcripts and noncoding RNAs. NEXT is a ternary complex composed of the RNA-binding protein RBM7, the scaffold zinc-knuckle protein ZCCHC8, and the helicase MTR4. While RNA interactions with RBM7 are known, it remains unclear how NEXT subunits collaborate to recognize and prepare substrates for degradation. Here, we show that MTR4 helicase activity is enhanced when associated with RBM7 and ZCCHC8. While uridine-rich substrates interact with RBM7 and are preferred, optimal activity is observed when substrates include a polyadenylated 3′ end. We identify a bipartite interaction of ZCCHC8 with MTR4 and uncover a role for the conserved C-terminal domain of ZCCHC8 in stimulating MTR4 helicase and ATPase activities. A crystal structure reveals that the ZCCHC8 C-terminal domain binds the helicase core in a manner that is distinct from that observed for Saccharomyces cerevisiae exosome cofactors Trf4p and Air2p. Our results are consistent with a model whereby effective targeting of substrates by NEXT entails recognition of elements within the substrate and activation of MTR4 helicase activity.
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78
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Abstract
The nuclear RNA exosome is an essential and versatile machinery that regulates maturation and degradation of a huge plethora of RNA species. The past two decades have witnessed remarkable progress in understanding the whole picture of its RNA substrates and the structural basis of its functions. In addition to the exosome itself, recent studies focusing on associated co-factors have been elucidating how the exosome is directed towards specific substrates. Moreover, it has been gradually realized that loss-of-function of exosome subunits affect multiple biological processes such as the DNA damage response, R-loop resolution, maintenance of genome integrity, RNA export, translation and cell differentiation. In this review, we summarize the current knowledge of the mechanisms of nuclear exosome-mediated RNA metabolism and discuss their physiological significance.
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79
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du Mee DJM, Ivanov M, Parker JP, Buratowski S, Marquardt S. Efficient termination of nuclear lncRNA transcription promotes mitochondrial genome maintenance. eLife 2018; 7:31989. [PMID: 29504936 PMCID: PMC5837560 DOI: 10.7554/elife.31989] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2017] [Accepted: 02/08/2018] [Indexed: 12/27/2022] Open
Abstract
Most DNA in the genomes of higher organisms does not code for proteins. RNA Polymerase II (Pol II) transcribes non-coding DNA into long non-coding RNAs (lncRNAs), but biological roles of lncRNA are unclear. We find that mutations in the yeast lncRNA CUT60 result in poor growth. Defective termination of CUT60 transcription causes read-through transcription across the ATP16 gene promoter. Read-through transcription localizes chromatin signatures associated with Pol II elongation to the ATP16 promoter. The act of Pol II elongation across this promoter represses functional ATP16 expression by a Transcriptional Interference (TI) mechanism. Atp16p function in the mitochondrial ATP-synthase complex promotes mitochondrial DNA stability. ATP16 repression by TI through inefficient termination of CUT60 therefore triggers mitochondrial genome loss. Our results expand the functional and mechanistic implications of non-coding DNA in eukaryotes by highlighting termination of nuclear lncRNA transcription as mechanism to stabilize an organellar genome.
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Affiliation(s)
- Dorine Jeanne Mariëtte du Mee
- Department of Plant and Environmental Sciences, Copenhagen Plant Science Centre, University of Copenhagen, Frederiksberg, Denmark
| | - Maxim Ivanov
- Department of Plant and Environmental Sciences, Copenhagen Plant Science Centre, University of Copenhagen, Frederiksberg, Denmark
| | - Joseph Paul Parker
- Department of Plant and Environmental Sciences, Copenhagen Plant Science Centre, University of Copenhagen, Frederiksberg, Denmark
| | - Stephen Buratowski
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, United States
| | - Sebastian Marquardt
- Department of Plant and Environmental Sciences, Copenhagen Plant Science Centre, University of Copenhagen, Frederiksberg, Denmark
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80
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Bresson S, Tollervey D. Surveillance-ready transcription: nuclear RNA decay as a default fate. Open Biol 2018; 8:170270. [PMID: 29563193 PMCID: PMC5881035 DOI: 10.1098/rsob.170270] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2017] [Accepted: 02/23/2018] [Indexed: 12/21/2022] Open
Abstract
Eukaryotic cells synthesize enormous quantities of RNA from diverse classes, most of which are subject to extensive processing. These processes are inherently error-prone, and cells have evolved robust quality control mechanisms to selectively remove aberrant transcripts. These surveillance pathways monitor all aspects of nuclear RNA biogenesis, and in addition remove nonfunctional transcripts arising from spurious transcription and a host of non-protein-coding RNAs (ncRNAs). Surprisingly, this is largely accomplished with only a handful of RNA decay enzymes. It has, therefore, been unclear how these factors efficiently distinguish between functional RNAs and huge numbers of diverse transcripts that must be degraded. Here we describe how bona fide transcripts are specifically protected, particularly by 5' and 3' modifications. Conversely, a plethora of factors associated with the nascent transcripts all act to recruit the RNA quality control, surveillance and degradation machinery. We conclude that initiating RNAPII is 'surveillance ready', with degradation being a default fate for all transcripts that lack specific protective features. We further postulate that this promiscuity is a key feature that allowed the proliferation of vast numbers of ncRNAs in eukaryotes, including humans.
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Affiliation(s)
- Stefan Bresson
- Wellcome Centre for Cell Biology, University of Edinburgh, Edinburgh, EH9 3BF, UK
| | - David Tollervey
- Wellcome Centre for Cell Biology, University of Edinburgh, Edinburgh, EH9 3BF, UK
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81
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Shichino Y, Otsubo Y, Kimori Y, Yamamoto M, Yamashita A. YTH-RNA-binding protein prevents deleterious expression of meiotic proteins by tethering their mRNAs to nuclear foci. eLife 2018; 7:32155. [PMID: 29424342 PMCID: PMC5807050 DOI: 10.7554/elife.32155] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2017] [Accepted: 01/31/2018] [Indexed: 12/24/2022] Open
Abstract
Accurate and extensive regulation of meiotic gene expression is crucial to distinguish germ cells from somatic cells. In the fission yeast Schizosaccharomyces pombe, a YTH family RNA-binding protein, Mmi1, directs the nuclear exosome-mediated elimination of meiotic transcripts during vegetative proliferation. Mmi1 also induces the formation of facultative heterochromatin at a subset of its target genes. Here, we show that Mmi1 prevents the mistimed expression of meiotic proteins by tethering their mRNAs to the nuclear foci. Mmi1 interacts with itself with the assistance of a homolog of Enhancer of Rudimentary, Erh1. Mmi1 self-interaction is required for foci formation, target transcript elimination, their nuclear retention, and protein expression inhibition. We propose that nuclear foci formed by Mmi1 are not only the site of RNA degradation, but also of sequestration of meiotic transcripts from the translation machinery.
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Affiliation(s)
- Yuichi Shichino
- Laboratory of Cell Responses, National Institute for Basic Biology, Okazaki, Japan
| | - Yoko Otsubo
- Laboratory of Cell Responses, National Institute for Basic Biology, Okazaki, Japan
| | - Yoshitaka Kimori
- Department of Imaging Science, Center for Novel Science Initiatives, National Institutes of Natural Sciences, Okazaki, Japan.,Laboratory of Biological Diversity, National Institute for Basic Biology, Okazaki, Japan.,Department of Basic Biology, School of Life Science, SOKENDAI (The Graduate University for Advanced Studies), Okazaki, Japan
| | - Masayuki Yamamoto
- Laboratory of Cell Responses, National Institute for Basic Biology, Okazaki, Japan.,Department of Basic Biology, School of Life Science, SOKENDAI (The Graduate University for Advanced Studies), Okazaki, Japan
| | - Akira Yamashita
- Laboratory of Cell Responses, National Institute for Basic Biology, Okazaki, Japan.,Department of Basic Biology, School of Life Science, SOKENDAI (The Graduate University for Advanced Studies), Okazaki, Japan
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82
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Abstract
Numerous surveillance pathways sculpt eukaryotic transcriptomes by degrading unneeded, defective, and potentially harmful noncoding RNAs (ncRNAs). Because aberrant and excess ncRNAs are largely degraded by exoribonucleases, a key characteristic of these RNAs is an accessible, protein-free 5' or 3' end. Most exoribonucleases function with cofactors that recognize ncRNAs with accessible 5' or 3' ends and/or increase the availability of these ends. Noncoding RNA surveillance pathways were first described in budding yeast, and there are now high-resolution structures of many components of the yeast pathways and significant mechanistic understanding as to how they function. Studies in human cells are revealing the ways in which these pathways both resemble and differ from their yeast counterparts, and are also uncovering numerous pathways that lack equivalents in budding yeast. In this review, we describe both the well-studied pathways uncovered in yeast and the new concepts that are emerging from studies in mammalian cells. We also discuss the ways in which surveillance pathways compete with chaperone proteins that transiently protect nascent ncRNA ends from exoribonucleases, with partner proteins that sequester these ends within RNPs, and with end modification pathways that protect the ends of some ncRNAs from nucleases.
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Affiliation(s)
- Cedric Belair
- RNA Biology Laboratory, Center for Cancer Research, National Cancer Institute , National Institutes of Health , Frederick , Maryland 21702 , United States
| | - Soyeong Sim
- RNA Biology Laboratory, Center for Cancer Research, National Cancer Institute , National Institutes of Health , Frederick , Maryland 21702 , United States
| | - Sandra L Wolin
- RNA Biology Laboratory, Center for Cancer Research, National Cancer Institute , National Institutes of Health , Frederick , Maryland 21702 , United States
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83
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Affiliation(s)
- Koichi Ogami
- a Department of Biological Sciences , Columbia University , New York , NY , USA.,b RIKEN Center for Life Science Technologies , Post-transcriptional Control Research Unit, Tsurumi , Yokohama , Japan
| | - James L Manley
- a Department of Biological Sciences , Columbia University , New York , NY , USA
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