1
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Cao X, Zhang Y, Ding Y, Wan Y. Identification of RNA structures and their roles in RNA functions. Nat Rev Mol Cell Biol 2024:10.1038/s41580-024-00748-6. [PMID: 38926530 DOI: 10.1038/s41580-024-00748-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/28/2024] [Indexed: 06/28/2024]
Abstract
The development of high-throughput RNA structure profiling methods in the past decade has greatly facilitated our ability to map and characterize different aspects of RNA structures transcriptome-wide in cell populations, single cells and single molecules. The resulting high-resolution data have provided insights into the static and dynamic nature of RNA structures, revealing their complexity as they perform their respective functions in the cell. In this Review, we discuss recent technical advances in the determination of RNA structures, and the roles of RNA structures in RNA biogenesis and functions, including in transcription, processing, translation, degradation, localization and RNA structure-dependent condensates. We also discuss the current understanding of how RNA structures could guide drug design for treating genetic diseases and battling pathogenic viruses, and highlight existing challenges and future directions in RNA structure research.
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Affiliation(s)
- Xinang Cao
- Stem Cell and Regenerative Biology, Genome Institute of Singapore, Singapore, Singapore
| | - Yueying Zhang
- Department of Cell and Developmental Biology, John Innes Centre, Norwich, UK
| | - Yiliang Ding
- Department of Cell and Developmental Biology, John Innes Centre, Norwich, UK.
| | - Yue Wan
- Stem Cell and Regenerative Biology, Genome Institute of Singapore, Singapore, Singapore.
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore.
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2
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Bose R, Saleem I, Mustoe AM. Causes, functions, and therapeutic possibilities of RNA secondary structure ensembles and alternative states. Cell Chem Biol 2024; 31:17-35. [PMID: 38199037 PMCID: PMC10842484 DOI: 10.1016/j.chembiol.2023.12.010] [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: 09/11/2023] [Revised: 11/21/2023] [Accepted: 12/12/2023] [Indexed: 01/12/2024]
Abstract
RNA secondary structure plays essential roles in encoding RNA regulatory fate and function. Most RNAs populate ensembles of alternatively paired states and are continually unfolded and refolded by cellular processes. Measuring these structural ensembles and their contributions to cellular function has traditionally posed major challenges, but new methods and conceptual frameworks are beginning to fill this void. In this review, we provide a mechanism- and function-centric compendium of the roles of RNA secondary structural ensembles and minority states in regulating the RNA life cycle, from transcription to degradation. We further explore how dysregulation of RNA structural ensembles contributes to human disease and discuss the potential of drugging alternative RNA states to therapeutically modulate RNA activity. The emerging paradigm of RNA structural ensembles as central to RNA function provides a foundation for a deeper understanding of RNA biology and new therapeutic possibilities.
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Affiliation(s)
- Ritwika Bose
- Therapeutic Innovation Center (THINC), Department of Biochemistry and Molecular Pharmacology, Baylor College of Medicine, Houston, TX, USA
| | - Irfana Saleem
- Therapeutic Innovation Center (THINC), Department of Biochemistry and Molecular Pharmacology, Baylor College of Medicine, Houston, TX, USA
| | - Anthony M Mustoe
- Therapeutic Innovation Center (THINC), Department of Biochemistry and Molecular Pharmacology, Baylor College of Medicine, Houston, TX, USA; Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, USA.
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3
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Nowzari ZR, Hale M, Ellis J, Biaesch S, Vangaveti S, Reddy K, Chen AA, Berglund JA. Mutation of two intronic nucleotides alters RNA structure and dynamics inhibiting MBNL1 and RBFOX1 regulated splicing of the Insulin Receptor. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.08.574689. [PMID: 38260517 PMCID: PMC10802415 DOI: 10.1101/2024.01.08.574689] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2024]
Abstract
Alternative splicing (AS) of Exon 11 of the Insulin Receptor ( INSR ) is highly regulated and disrupted in several human disorders. To better understand INSR exon 11 AS regulation, splicing activity of an INSR exon 11 minigene reporter was measured across a gradient of the AS regulator muscleblind-like 1 protein (MBNL1). The RNA-binding protein Fox-1 (RBFOX1) was added to determine its impact on MBNL1-regulated splicing. The role of the RBFOX1 UGCAUG binding site within intron 11 was assessed across the MBNL1 gradient. Mutating the UGCAUG motif inhibited RBFOX1 regulation of exon 11 and had the unexpected effect of reducing MBNL1 regulation of this exon. Molecular dynamics simulations showed that exon 11 and the adjacent RNA adopts a dynamically stable conformation. Mutation of the RBFOX1 binding site altered RNA structure and dynamics, while a mutation that created an optimal MBNL1 binding site at the RBFOX1 site shifted the RNA back to wild type. An antisense oligonucleotide (ASO) was used to confirm the structure in this region of the pre-mRNA. This example of intronic mutations shifting pre-mRNA structure and dynamics to modulate splicing suggests RNA structure and dynamics should be taken into consideration for AS regulation and therapeutic interventions targeting pre-mRNA.
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4
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Schmok JC, Jain M, Street LA, Tankka AT, Schafer D, Her HL, Elmsaouri S, Gosztyla ML, Boyle EA, Jagannatha P, Luo EC, Kwon EJ, Jovanovic M, Yeo GW. Large-scale evaluation of the ability of RNA-binding proteins to activate exon inclusion. Nat Biotechnol 2024:10.1038/s41587-023-02014-0. [PMID: 38168984 DOI: 10.1038/s41587-023-02014-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2023] [Accepted: 09/29/2023] [Indexed: 01/05/2024]
Abstract
RNA-binding proteins (RBPs) modulate alternative splicing outcomes to determine isoform expression and cellular survival. To identify RBPs that directly drive alternative exon inclusion, we developed tethered function luciferase-based splicing reporters that provide rapid, scalable and robust readouts of exon inclusion changes and used these to evaluate 718 human RBPs. We performed enhanced cross-linking immunoprecipitation, RNA sequencing and affinity purification-mass spectrometry to investigate a subset of candidates with no prior association with splicing. Integrative analysis of these assays indicates surprising roles for TRNAU1AP, SCAF8 and RTCA in the modulation of hundreds of endogenous splicing events. We also leveraged our tethering assays and top candidates to identify potent and compact exon inclusion activation domains for splicing modulation applications. Using these identified domains, we engineered programmable fusion proteins that outperform current artificial splicing factors at manipulating inclusion of reporter and endogenous exons. This tethering approach characterizes the ability of RBPs to induce exon inclusion and yields new molecular parts for programmable splicing control.
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Affiliation(s)
- Jonathan C Schmok
- Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, CA, USA
- Sanford Stem Cell Institute Innovation Center and Stem Cell Program, University of California San Diego, La Jolla, CA, USA
- Institute for Genomic Medicine, University of California San Diego, La Jolla, CA, USA
- Department of Bioengineering, University of California San Diego, La Jolla, CA, USA
| | - Manya Jain
- Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, CA, USA
- Sanford Stem Cell Institute Innovation Center and Stem Cell Program, University of California San Diego, La Jolla, CA, USA
- Institute for Genomic Medicine, University of California San Diego, La Jolla, CA, USA
| | - Lena A Street
- Department of Biological Sciences, Columbia University, New York, NY, USA
| | - Alex T Tankka
- Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, CA, USA
- Sanford Stem Cell Institute Innovation Center and Stem Cell Program, University of California San Diego, La Jolla, CA, USA
- Institute for Genomic Medicine, University of California San Diego, La Jolla, CA, USA
| | - Danielle Schafer
- Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, CA, USA
- Sanford Stem Cell Institute Innovation Center and Stem Cell Program, University of California San Diego, La Jolla, CA, USA
- Institute for Genomic Medicine, University of California San Diego, La Jolla, CA, USA
| | - Hsuan-Lin Her
- Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, CA, USA
- Sanford Stem Cell Institute Innovation Center and Stem Cell Program, University of California San Diego, La Jolla, CA, USA
- Institute for Genomic Medicine, University of California San Diego, La Jolla, CA, USA
| | - Sara Elmsaouri
- Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, CA, USA
- Sanford Stem Cell Institute Innovation Center and Stem Cell Program, University of California San Diego, La Jolla, CA, USA
- Institute for Genomic Medicine, University of California San Diego, La Jolla, CA, USA
| | - Maya L Gosztyla
- Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, CA, USA
- Sanford Stem Cell Institute Innovation Center and Stem Cell Program, University of California San Diego, La Jolla, CA, USA
- Institute for Genomic Medicine, University of California San Diego, La Jolla, CA, USA
| | - Evan A Boyle
- Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, CA, USA
- Sanford Stem Cell Institute Innovation Center and Stem Cell Program, University of California San Diego, La Jolla, CA, USA
- Institute for Genomic Medicine, University of California San Diego, La Jolla, CA, USA
| | - Pratibha Jagannatha
- Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, CA, USA
- Sanford Stem Cell Institute Innovation Center and Stem Cell Program, University of California San Diego, La Jolla, CA, USA
- Institute for Genomic Medicine, University of California San Diego, La Jolla, CA, USA
| | - En-Ching Luo
- Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, CA, USA
- Sanford Stem Cell Institute Innovation Center and Stem Cell Program, University of California San Diego, La Jolla, CA, USA
- Institute for Genomic Medicine, University of California San Diego, La Jolla, CA, USA
| | - Ester J Kwon
- Department of Bioengineering, University of California San Diego, La Jolla, CA, USA
| | - Marko Jovanovic
- Department of Biological Sciences, Columbia University, New York, NY, USA
| | - Gene W Yeo
- Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, CA, USA.
- Sanford Stem Cell Institute Innovation Center and Stem Cell Program, University of California San Diego, La Jolla, CA, USA.
- Institute for Genomic Medicine, University of California San Diego, La Jolla, CA, USA.
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5
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Taylor K, Piasecka A, Kajdasz A, Brzęk A, Polay Espinoza M, Bourgeois CF, Jankowski A, Borowiak M, Raczyńska KD, Sznajder ŁJ, Sobczak K. Modulatory role of RNA helicases in MBNL-dependent alternative splicing regulation. Cell Mol Life Sci 2023; 80:335. [PMID: 37882878 PMCID: PMC10602967 DOI: 10.1007/s00018-023-04927-0] [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: 01/31/2023] [Revised: 07/14/2023] [Accepted: 08/17/2023] [Indexed: 10/27/2023]
Abstract
Muscleblind-like splicing regulators (MBNLs) activate or repress the inclusion of alternative splicing (AS) events, enabling the developmental transition of fetal mRNA splicing isoforms to their adult forms. Herein, we sought to elaborate the mechanism by which MBNLs mediate AS related to biological processes. We evaluated the functional role of DEAD-box (DDX) RNA helicases, DDX5 and DDX17 in MBNL-dependent AS regulation. Whole-transcriptome analysis and validation approaches revealed a handful of MBNLs-dependent AS events to be affected by DDX5 and DDX17 in mostly an opposite manner. The opposite expression patterns of these two groups of factors during muscle development and coordination of fetal-to-adult splicing transition indicate the importance of these proteins at early stages of development. The identified pathways of how the helicases modulate MBNL splicing activity include DDX5 and DDX17-dependent changes in the ratio of MBNL splicing isoforms and most likely changes in accessibility of MBNL-binding sites. Another pathway involves the mode of action of the helicases independent of MBNL activity. These findings lead to a deeper understanding of the network of interdependencies between RNA-binding proteins and constitute a valuable element in the discussion on developmental homeostasis and pathological states in which the studied protein factors play a significant role.
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Affiliation(s)
- Katarzyna Taylor
- Department of Gene Expression, Institute of Molecular Biology and Biotechnology, Adam Mickiewicz University, Uniwersytetu Poznanskiego 6, 61-614, Poznan, Poland.
| | - Agnieszka Piasecka
- Department of Gene Expression, Institute of Molecular Biology and Biotechnology, Adam Mickiewicz University, Uniwersytetu Poznanskiego 6, 61-614, Poznan, Poland
| | - Arkadiusz Kajdasz
- Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14, 61-704, Poznan, Poland
| | - Aleksandra Brzęk
- Department of Gene Expression, Institute of Molecular Biology and Biotechnology, Adam Mickiewicz University, Uniwersytetu Poznanskiego 6, 61-614, Poznan, Poland
| | - Micaela Polay Espinoza
- Laboratoire de Biologie et Modelisation de la Cellule, Ecole Normale Superieure de Lyon, CNRS, UMR 5239, Inserm, U1293, Universite Claude Bernard Lyon 1, 46 Allee d'Italie, 69364, Lyon, France
| | - Cyril F Bourgeois
- Laboratoire de Biologie et Modelisation de la Cellule, Ecole Normale Superieure de Lyon, CNRS, UMR 5239, Inserm, U1293, Universite Claude Bernard Lyon 1, 46 Allee d'Italie, 69364, Lyon, France
| | - Artur Jankowski
- Department of Gene Expression, Institute of Molecular Biology and Biotechnology, Adam Mickiewicz University, Uniwersytetu Poznanskiego 6, 61-614, Poznan, Poland
| | - Małgorzata Borowiak
- Department of Gene Expression, Institute of Molecular Biology and Biotechnology, Adam Mickiewicz University, Uniwersytetu Poznanskiego 6, 61-614, Poznan, Poland
| | - Katarzyna D Raczyńska
- Department of Gene Expression, Institute of Molecular Biology and Biotechnology, Adam Mickiewicz University, Uniwersytetu Poznanskiego 6, 61-614, Poznan, Poland
| | - Łukasz J Sznajder
- Department of Molecular Genetics and Microbiology, Center for NeuroGenetics and the Genetics Institute, University of Florida, College of Medicine, Gainesville, FL, 32610, USA
- Department of Chemistry and Biochemistry, University of Nevada, Las Vegas, NV, 89154, USA
| | - Krzysztof Sobczak
- Department of Gene Expression, Institute of Molecular Biology and Biotechnology, Adam Mickiewicz University, Uniwersytetu Poznanskiego 6, 61-614, Poznan, Poland.
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6
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Vorobeva MA, Skvortsov DA, Pervouchine DD. Cooperation and Competition of RNA Secondary Structure and RNA-Protein Interactions in the Regulation of Alternative Splicing. Acta Naturae 2023; 15:23-31. [PMID: 38234601 PMCID: PMC10790352 DOI: 10.32607/actanaturae.26826] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2023] [Accepted: 10/31/2023] [Indexed: 01/19/2024] Open
Abstract
The regulation of alternative splicing in eukaryotic cells is carried out through the coordinated action of a large number of factors, including RNA-binding proteins and RNA structure. The RNA structure influences alternative splicing by blocking cis-regulatory elements, or bringing them closer or farther apart. In combination with RNA-binding proteins, it generates transcript conformations that help to achieve the necessary splicing outcome. However, the binding of regulatory proteins depends on RNA structure and, vice versa, the formation of RNA structure depends on the interaction with regulators. Therefore, RNA structure and RNA-binding proteins are inseparable components of common regulatory mechanisms. This review highlights examples of alternative splicing regulation by RNA-binding proteins, the regulation through local and long-range RNA structures, as well as how these elements work together, cooperate, and compete.
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Affiliation(s)
- M. A. Vorobeva
- M.V. Lomonosov Moscow State University, Moscow, 119192 Russian Federation
| | - D. A. Skvortsov
- M.V. Lomonosov Moscow State University, Moscow, 119192 Russian Federation
| | - D. D. Pervouchine
- Skolkovo Institute of Science and Technology, Moscow, 121205 Russian Federation
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7
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Xie J, Zou W, Tugizova M, Shen K, Wang X. MBL-1 and EEL-1 affect the splicing and protein levels of MEC-3 to control dendrite complexity. PLoS Genet 2023; 19:e1010941. [PMID: 37729192 PMCID: PMC10511122 DOI: 10.1371/journal.pgen.1010941] [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: 12/20/2022] [Accepted: 08/28/2023] [Indexed: 09/22/2023] Open
Abstract
Transcription factors (TFs) play critical roles in specifying many aspects of neuronal cell fate including dendritic morphology. How TFs are accurately regulated during neuronal morphogenesis is not fully understood. Here, we show that LIM homeodomain protein MEC-3, the key TF for C. elegans PVD dendrite morphogenesis, is regulated by both alternative splicing and an E3 ubiquitin ligase. The mec-3 gene generates several transcripts by alternative splicing. We find that mbl-1, the orthologue of the muscular dystrophy disease gene muscleblind-like (MBNL), is required for PVD dendrite arbor formation. Our data suggest mbl-1 regulates the alternative splicing of mec-3 to produce its long isoform. Deleting the long isoform of mec-3(deExon2) causes reduction of dendrite complexity. Through a genetic modifier screen, we find that mutation in the E3 ubiquitin ligase EEL-1 suppresses mbl-1 phenotype. eel-1 mutants also suppress mec-3(deExon2) mutant but not the mec-3 null phenotype. Loss of EEL-1 alone leads to excessive dendrite branches. Together, these results indicate that MEC-3 is fine-tuned by alternative splicing and the ubiquitin system to produce the optimal level of dendrite branches.
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Affiliation(s)
- Jianxin Xie
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
- College of Life Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Wei Zou
- The Fourth Affiliated Hospital, Zhejiang University School of Medicine, Yiwu, China
- Institute of Translational Medicine, Zhejiang University, Hangzhou, China
- Howard Hughes Medical Institute, Department of Biology, Stanford University, Stanford, California, United States of America
| | - Madina Tugizova
- Howard Hughes Medical Institute, Department of Biology, Stanford University, Stanford, California, United States of America
| | - Kang Shen
- Howard Hughes Medical Institute, Department of Biology, Stanford University, Stanford, California, United States of America
| | - Xiangming Wang
- National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
- Department of Cell Biology, School of Basic Medical Science, Capital Medical University, Beijing, China
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8
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Jin B, Zhu J, Pan T, Yang Y, Liang L, Zhou Y, Zhang T, Teng Y, Wang Z, Wang X, Tian Q, Guo B, Li H, Chen T. MEN1 is a regulator of alternative splicing and prevents R-loop-induced genome instability through suppression of RNA polymerase II elongation. Nucleic Acids Res 2023; 51:7951-7971. [PMID: 37395406 PMCID: PMC10450199 DOI: 10.1093/nar/gkad548] [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: 10/02/2022] [Revised: 06/02/2023] [Accepted: 06/15/2023] [Indexed: 07/04/2023] Open
Abstract
The fidelity of alternative splicing (AS) patterns is essential for growth development and cell fate determination. However, the scope of the molecular switches that regulate AS remains largely unexplored. Here we show that MEN1 is a previously unknown splicing regulatory factor. MEN1 deletion resulted in reprogramming of AS patterns in mouse lung tissue and human lung cancer cells, suggesting that MEN1 has a general function in regulating alternative precursor mRNA splicing. MEN1 altered exon skipping and the abundance of mRNA splicing isoforms of certain genes with suboptimal splice sites. Chromatin immunoprecipitation and chromosome walking assays revealed that MEN1 favored the accumulation of RNA polymerase II (Pol II) in regions encoding variant exons. Our data suggest that MEN1 regulates AS by slowing the Pol II elongation rate and that defects in these processes trigger R-loop formation, DNA damage accumulation and genome instability. Furthermore, we identified 28 MEN1-regulated exon-skipping events in lung cancer cells that were closely correlated with survival in patients with lung adenocarcinoma, and MEN1 deficiency sensitized lung cancer cells to splicing inhibitors. Collectively, these findings led to the identification of a novel biological role for menin in maintaining AS homeostasis and link this role to the regulation of cancer cell behavior.
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Affiliation(s)
- Bangming Jin
- Department of Physiology, School of Basic Medical Sciences, Guizhou Medical University, 550025 Guiyang, China
- Department of Surgery, Affiliated Hospital of Guizhou Medical University, 550025 Guiyang, China
- Transformation Engineering Research Center of Chronic Disease Diagnosis and Treatment, Guizhou Medical University, Guiyang, China
- Guizhou Provincial Key Laboratory of Pathogenesis and Drug Research on Common Chronic Diseases, Guizhou Medical University, 550025 Guiyang, China
| | - Jiamei Zhu
- Department of Physiology, School of Basic Medical Sciences, Guizhou Medical University, 550025 Guiyang, China
- Transformation Engineering Research Center of Chronic Disease Diagnosis and Treatment, Guizhou Medical University, Guiyang, China
- Guizhou Provincial Key Laboratory of Pathogenesis and Drug Research on Common Chronic Diseases, Guizhou Medical University, 550025 Guiyang, China
| | - Ting Pan
- Department of Physiology, School of Basic Medical Sciences, Guizhou Medical University, 550025 Guiyang, China
- Transformation Engineering Research Center of Chronic Disease Diagnosis and Treatment, Guizhou Medical University, Guiyang, China
- Guizhou Provincial Key Laboratory of Pathogenesis and Drug Research on Common Chronic Diseases, Guizhou Medical University, 550025 Guiyang, China
| | - Yunqiao Yang
- Department of Physiology, School of Basic Medical Sciences, Guizhou Medical University, 550025 Guiyang, China
- Department of Surgery, Affiliated Hospital of Guizhou Medical University, 550025 Guiyang, China
- Transformation Engineering Research Center of Chronic Disease Diagnosis and Treatment, Guizhou Medical University, Guiyang, China
- Guizhou Provincial Key Laboratory of Pathogenesis and Drug Research on Common Chronic Diseases, Guizhou Medical University, 550025 Guiyang, China
| | - Li Liang
- Department of Physiology, School of Basic Medical Sciences, Guizhou Medical University, 550025 Guiyang, China
- Transformation Engineering Research Center of Chronic Disease Diagnosis and Treatment, Guizhou Medical University, Guiyang, China
- Guizhou Provincial Key Laboratory of Pathogenesis and Drug Research on Common Chronic Diseases, Guizhou Medical University, 550025 Guiyang, China
| | - Yuxia Zhou
- Department of Physiology, School of Basic Medical Sciences, Guizhou Medical University, 550025 Guiyang, China
- Transformation Engineering Research Center of Chronic Disease Diagnosis and Treatment, Guizhou Medical University, Guiyang, China
- Guizhou Provincial Key Laboratory of Pathogenesis and Drug Research on Common Chronic Diseases, Guizhou Medical University, 550025 Guiyang, China
| | - Tuo Zhang
- Department of Physiology, School of Basic Medical Sciences, Guizhou Medical University, 550025 Guiyang, China
- Transformation Engineering Research Center of Chronic Disease Diagnosis and Treatment, Guizhou Medical University, Guiyang, China
- Guizhou Provincial Key Laboratory of Pathogenesis and Drug Research on Common Chronic Diseases, Guizhou Medical University, 550025 Guiyang, China
| | - Yin Teng
- Department of Surgery, Affiliated Hospital of Guizhou Medical University, 550025 Guiyang, China
- Guizhou Institute of Precision Medicine, Affiliated Hospital of Guizhou Medical University, 550025 Guiyang, China
| | - Ziming Wang
- Department of Physiology, School of Basic Medical Sciences, Guizhou Medical University, 550025 Guiyang, China
- Transformation Engineering Research Center of Chronic Disease Diagnosis and Treatment, Guizhou Medical University, Guiyang, China
- Guizhou Provincial Key Laboratory of Pathogenesis and Drug Research on Common Chronic Diseases, Guizhou Medical University, 550025 Guiyang, China
| | - Xuyan Wang
- Department of Physiology, School of Basic Medical Sciences, Guizhou Medical University, 550025 Guiyang, China
- Transformation Engineering Research Center of Chronic Disease Diagnosis and Treatment, Guizhou Medical University, Guiyang, China
- Guizhou Provincial Key Laboratory of Pathogenesis and Drug Research on Common Chronic Diseases, Guizhou Medical University, 550025 Guiyang, China
| | - Qianting Tian
- Transformation Engineering Research Center of Chronic Disease Diagnosis and Treatment, Guizhou Medical University, Guiyang, China
- Guizhou Institute of Precision Medicine, Affiliated Hospital of Guizhou Medical University, 550025 Guiyang, China
| | - Bing Guo
- Department of Physiology, School of Basic Medical Sciences, Guizhou Medical University, 550025 Guiyang, China
- Transformation Engineering Research Center of Chronic Disease Diagnosis and Treatment, Guizhou Medical University, Guiyang, China
- Guizhou Provincial Key Laboratory of Pathogenesis and Drug Research on Common Chronic Diseases, Guizhou Medical University, 550025 Guiyang, China
| | - Haiyang Li
- Department of Surgery, Affiliated Hospital of Guizhou Medical University, 550025 Guiyang, China
- Guizhou Institute of Precision Medicine, Affiliated Hospital of Guizhou Medical University, 550025 Guiyang, China
| | - Tengxiang Chen
- Department of Physiology, School of Basic Medical Sciences, Guizhou Medical University, 550025 Guiyang, China
- Department of Surgery, Affiliated Hospital of Guizhou Medical University, 550025 Guiyang, China
- Transformation Engineering Research Center of Chronic Disease Diagnosis and Treatment, Guizhou Medical University, Guiyang, China
- Guizhou Provincial Key Laboratory of Pathogenesis and Drug Research on Common Chronic Diseases, Guizhou Medical University, 550025 Guiyang, China
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9
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Giménez-Bejarano A, Alegre-Cortés E, Yakhine-Diop SMS, Gómez-Suaga P, Fuentes JM. Mitochondrial Dysfunction in Repeat Expansion Diseases. Antioxidants (Basel) 2023; 12:1593. [PMID: 37627588 PMCID: PMC10451345 DOI: 10.3390/antiox12081593] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2023] [Revised: 07/29/2023] [Accepted: 08/02/2023] [Indexed: 08/27/2023] Open
Abstract
Repeat expansion diseases are a group of neuromuscular and neurodegenerative disorders characterized by expansions of several successive repeated DNA sequences. Currently, more than 50 repeat expansion diseases have been described. These disorders involve diverse pathogenic mechanisms, including loss-of-function mechanisms, toxicity associated with repeat RNA, or repeat-associated non-ATG (RAN) products, resulting in impairments of cellular processes and damaged organelles. Mitochondria, double membrane organelles, play a crucial role in cell energy production, metabolic processes, calcium regulation, redox balance, and apoptosis regulation. Its dysfunction has been implicated in the pathogenesis of repeat expansion diseases. In this review, we provide an overview of the signaling pathways or proteins involved in mitochondrial functioning described in these disorders. The focus of this review will be on the analysis of published data related to three representative repeat expansion diseases: Huntington's disease, C9orf72-frontotemporal dementia/amyotrophic lateral sclerosis, and myotonic dystrophy type 1. We will discuss the common effects observed in all three repeat expansion disorders and their differences. Additionally, we will address the current gaps in knowledge and propose possible new lines of research. Importantly, this group of disorders exhibit alterations in mitochondrial dynamics and biogenesis, with specific proteins involved in these processes having been identified. Understanding the underlying mechanisms of mitochondrial alterations in these disorders can potentially lead to the development of neuroprotective strategies.
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Affiliation(s)
- Alberto Giménez-Bejarano
- Departamento de Bioquímica y Biología Molecular y Genética, Facultad de Enfermería y Terapia Ocupacional, Universidad de Extremadura, 10003 Cáceres, Spain; (A.G.-B.); (E.A.-C.); (S.M.S.Y.-D.); (P.G.-S.)
- Centro de Investigación Biomédica en Red en Enfermedades Neurodegenerativa, Instituto de Salus Carlos III (CIBER-CIBERNED-ISCIII), 28029 Madrid, Spain
- Instituto de Investigación Biosanitaria de Extremadura (INUBE), 10003 Cáceres, Spain
| | - Eva Alegre-Cortés
- Departamento de Bioquímica y Biología Molecular y Genética, Facultad de Enfermería y Terapia Ocupacional, Universidad de Extremadura, 10003 Cáceres, Spain; (A.G.-B.); (E.A.-C.); (S.M.S.Y.-D.); (P.G.-S.)
- Centro de Investigación Biomédica en Red en Enfermedades Neurodegenerativa, Instituto de Salus Carlos III (CIBER-CIBERNED-ISCIII), 28029 Madrid, Spain
- Instituto de Investigación Biosanitaria de Extremadura (INUBE), 10003 Cáceres, Spain
| | - Sokhna M. S. Yakhine-Diop
- Departamento de Bioquímica y Biología Molecular y Genética, Facultad de Enfermería y Terapia Ocupacional, Universidad de Extremadura, 10003 Cáceres, Spain; (A.G.-B.); (E.A.-C.); (S.M.S.Y.-D.); (P.G.-S.)
- Centro de Investigación Biomédica en Red en Enfermedades Neurodegenerativa, Instituto de Salus Carlos III (CIBER-CIBERNED-ISCIII), 28029 Madrid, Spain
- Instituto de Investigación Biosanitaria de Extremadura (INUBE), 10003 Cáceres, Spain
| | - Patricia Gómez-Suaga
- Departamento de Bioquímica y Biología Molecular y Genética, Facultad de Enfermería y Terapia Ocupacional, Universidad de Extremadura, 10003 Cáceres, Spain; (A.G.-B.); (E.A.-C.); (S.M.S.Y.-D.); (P.G.-S.)
- Centro de Investigación Biomédica en Red en Enfermedades Neurodegenerativa, Instituto de Salus Carlos III (CIBER-CIBERNED-ISCIII), 28029 Madrid, Spain
- Instituto de Investigación Biosanitaria de Extremadura (INUBE), 10003 Cáceres, Spain
| | - José M. Fuentes
- Departamento de Bioquímica y Biología Molecular y Genética, Facultad de Enfermería y Terapia Ocupacional, Universidad de Extremadura, 10003 Cáceres, Spain; (A.G.-B.); (E.A.-C.); (S.M.S.Y.-D.); (P.G.-S.)
- Centro de Investigación Biomédica en Red en Enfermedades Neurodegenerativa, Instituto de Salus Carlos III (CIBER-CIBERNED-ISCIII), 28029 Madrid, Spain
- Instituto de Investigación Biosanitaria de Extremadura (INUBE), 10003 Cáceres, Spain
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10
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Ebersberger S, Hipp C, Mulorz MM, Buchbender A, Hubrich D, Kang HS, Martínez-Lumbreras S, Kristofori P, Sutandy FXR, Llacsahuanga Allcca L, Schönfeld J, Bakisoglu C, Busch A, Hänel H, Tretow K, Welzel M, Di Liddo A, Möckel MM, Zarnack K, Ebersberger I, Legewie S, Luck K, Sattler M, König J. FUBP1 is a general splicing factor facilitating 3' splice site recognition and splicing of long introns. Mol Cell 2023:S1097-2765(23)00516-6. [PMID: 37506698 DOI: 10.1016/j.molcel.2023.07.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2023] [Revised: 05/19/2023] [Accepted: 07/03/2023] [Indexed: 07/30/2023]
Abstract
Splicing of pre-mRNAs critically contributes to gene regulation and proteome expansion in eukaryotes, but our understanding of the recognition and pairing of splice sites during spliceosome assembly lacks detail. Here, we identify the multidomain RNA-binding protein FUBP1 as a key splicing factor that binds to a hitherto unknown cis-regulatory motif. By collecting NMR, structural, and in vivo interaction data, we demonstrate that FUBP1 stabilizes U2AF2 and SF1, key components at the 3' splice site, through multivalent binding interfaces located within its disordered regions. Transcriptional profiling and kinetic modeling reveal that FUBP1 is required for efficient splicing of long introns, which is impaired in cancer patients harboring FUBP1 mutations. Notably, FUBP1 interacts with numerous U1 snRNP-associated proteins, suggesting a unique role for FUBP1 in splice site bridging for long introns. We propose a compelling model for 3' splice site recognition of long introns, which represent 80% of all human introns.
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Affiliation(s)
| | - Clara Hipp
- Institute of Structural Biology, Helmholtz Center Munich, 85764 Neuherberg, Germany; Bavarian NMR Center, Department of Bioscience, School of Natural Sciences, Technical University of Munich, 85747 Garching, Germany
| | - Miriam M Mulorz
- Institute of Molecular Biology (IMB) gGmbH, 55128 Mainz, Germany
| | | | - Dalmira Hubrich
- Institute of Molecular Biology (IMB) gGmbH, 55128 Mainz, Germany
| | - Hyun-Seo Kang
- Institute of Structural Biology, Helmholtz Center Munich, 85764 Neuherberg, Germany; Bavarian NMR Center, Department of Bioscience, School of Natural Sciences, Technical University of Munich, 85747 Garching, Germany
| | - Santiago Martínez-Lumbreras
- Institute of Structural Biology, Helmholtz Center Munich, 85764 Neuherberg, Germany; Bavarian NMR Center, Department of Bioscience, School of Natural Sciences, Technical University of Munich, 85747 Garching, Germany
| | - Panajot Kristofori
- Department of Systems Biology, Institute for Biomedical Genetics (IBMG), University of Stuttgart, 70569 Stuttgart, Germany
| | | | | | - Jonas Schönfeld
- Institute of Molecular Biology (IMB) gGmbH, 55128 Mainz, Germany
| | - Cem Bakisoglu
- Buchmann Institute for Molecular Life Sciences & Institute of Molecular Biosciences, Goethe University Frankfurt, 60438 Frankfurt am Main, Germany
| | - Anke Busch
- Institute of Molecular Biology (IMB) gGmbH, 55128 Mainz, Germany
| | - Heike Hänel
- Institute of Molecular Biology (IMB) gGmbH, 55128 Mainz, Germany
| | - Kerstin Tretow
- Institute of Molecular Biology (IMB) gGmbH, 55128 Mainz, Germany
| | - Mareen Welzel
- Institute of Molecular Biology (IMB) gGmbH, 55128 Mainz, Germany
| | | | - Martin M Möckel
- Institute of Molecular Biology (IMB) gGmbH, 55128 Mainz, Germany
| | - Kathi Zarnack
- Buchmann Institute for Molecular Life Sciences & Institute of Molecular Biosciences, Goethe University Frankfurt, 60438 Frankfurt am Main, Germany; CardioPulmonary Institute (CPI), 35392 Gießen, Germany
| | - Ingo Ebersberger
- Applied Bioinformatics Group, Institute of Cell Biology and Neuroscience, Goethe University Frankfurt, 60438 Frankfurt am Main, Germany; Senckenberg Biodiversity and Climate Research Center (S-BIK-F), 60325 Frankfurt am Main, Germany; LOEWE Center for Translational Biodiversity Genomics (TBG), 60325 Frankfurt am Main, Germany
| | - Stefan Legewie
- Department of Systems Biology, Institute for Biomedical Genetics (IBMG), University of Stuttgart, 70569 Stuttgart, Germany; Stuttgart Research Center for Systems Biology (SRCSB), University of Stuttgart, 70569 Stuttgart, Germany
| | - Katja Luck
- Institute of Molecular Biology (IMB) gGmbH, 55128 Mainz, Germany.
| | - Michael Sattler
- Institute of Structural Biology, Helmholtz Center Munich, 85764 Neuherberg, Germany; Bavarian NMR Center, Department of Bioscience, School of Natural Sciences, Technical University of Munich, 85747 Garching, Germany.
| | - Julian König
- Institute of Molecular Biology (IMB) gGmbH, 55128 Mainz, Germany.
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11
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Ellis JA, Hale MA, Cleary JD, Wang E, Andrew Berglund J. Alternative splicing outcomes across an RNA-binding protein concentration gradient. J Mol Biol 2023:168156. [PMID: 37230319 DOI: 10.1016/j.jmb.2023.168156] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2023] [Revised: 04/18/2023] [Accepted: 05/17/2023] [Indexed: 05/27/2023]
Abstract
Alternative splicing (AS) is a dynamic RNA processing step that produces multiple RNA isoforms from a single pre-mRNA transcript and contributes to the complexity of the cellular transcriptome and proteome. This process is regulated through a network of cis-regulatory sequence elements and trans-acting factors, most-notably RNA binding proteins (RBPs). The muscleblind-like (MBNL) and RNA binding fox-1 homolog (RBFOX) are two well characterized families of RBPs that regulate fetal to adult AS transitions critical for proper muscle, heart, and central nervous system development. To better understand how the concentration of these RBPs influences AS transcriptome wide, we engineered a MBNL1 and RBFOX1 inducible HEK-293 cell line. Modest induction of exogenous RBFOX1 in this cell line modulated MBNL1-dependent AS outcomes in 3 skipped exon events, despite significant levels of endogenous RBFOX1 and RBFOX2. Due to background RBFOX levels, we conducted a focused analysis of dose-dependent MBNL1 skipped exon AS outcomes and generated transcriptome wide dose-response curves. Analysis of this data demonstrates that MBNL1-regulated exclusion events may require higher concentrations of MBNL1 protein to properly regulate AS outcomes compared to inclusion events and that multiple arrangements of YGCY motifs can produce similar splicing outcomes. These results suggest that rather than a simple relationship between the organization of RBP binding sites and a specific splicing outcome, that complex interaction networks govern both AS inclusion and exclusion events across a RBP gradient.
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Affiliation(s)
- Joseph A Ellis
- Department of Biochemistry & Molecular Biology & Center for NeuroGenetics, College of Medicine, University of Florida, Gainesville, Florida 32610, United States; The RNA Institute, College of Arts and Sciences, University at Albany, SUNY, Albany, NY 12222, United States
| | - Melissa A Hale
- Department of Biochemistry & Molecular Biology & Center for NeuroGenetics, College of Medicine, University of Florida, Gainesville, Florida 32610, United States; Department of Neurology, School of Medicine, Virginia Commonwealth University, Richmond, Virginia 23298, United States
| | - John D Cleary
- The RNA Institute, College of Arts and Sciences, University at Albany, SUNY, Albany, NY 12222, United States
| | - Eric Wang
- Department of Microbiology and Molecular Genetics & Center for NeuroGenetics, College of Medicine, University of Florida, Gainesville, Florida 32610, United States
| | - J Andrew Berglund
- Department of Biochemistry & Molecular Biology & Center for NeuroGenetics, College of Medicine, University of Florida, Gainesville, Florida 32610, United States; The RNA Institute, College of Arts and Sciences, University at Albany, SUNY, Albany, NY 12222, United States; Department of Biological Sciences, College of Arts and Sciences, University at Albany, SUNY, Albany, NY 12222, United States; RNA Institute, State University of New York at Albany, LSRB-2033, 1400 Washington Avenue, Albany, New York, 12222.
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12
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Reis RS. Thermomorphogenesis: Opportunities and challenges in posttranscriptional regulation. JOURNAL OF EXPERIMENTAL BOTANY 2023:7134107. [PMID: 37082809 DOI: 10.1093/jxb/erad134] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Indexed: 05/03/2023]
Abstract
Plants exposed to mildly elevated temperatures display morphological and developmental changes collectively termed thermomorphogenesis. This adaptative process has several undesirable consequences to food production, including yield reduction and increased vulnerability to pathogens. Understanding thermomorphogenesis is, thus, critical for understanding how plants will respond to increasingly warmer temperature conditions, such as those caused by climate change. Recently, we have made major advances in that direction, and it has become apparent that plants resource to a broad range of molecules and molecular mechanisms to perceive and respond to increases in environmental temperature. However, most of our efforts have been focused on regulation of transcription and protein abundance and activity, with an important gap encompassing nearly all processes involving RNA (i.e., posttranscriptional regulation). Here, I summarized our current knowledge of thermomorphogenesis involving transcriptional, posttranscriptional, and posttranslational regulation, focused on opportunities and challenges in understanding posttranscriptional regulation-a fertile field for exciting new discoveries.
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Affiliation(s)
- Rodrigo S Reis
- Institute of Plant Sciences, University of Bern, Altenbergrain 21, Bern, Switzerland
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13
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Rogalska ME, Vivori C, Valcárcel J. Regulation of pre-mRNA splicing: roles in physiology and disease, and therapeutic prospects. Nat Rev Genet 2023; 24:251-269. [PMID: 36526860 DOI: 10.1038/s41576-022-00556-8] [Citation(s) in RCA: 41] [Impact Index Per Article: 41.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/10/2022] [Indexed: 12/23/2022]
Abstract
The removal of introns from mRNA precursors and its regulation by alternative splicing are key for eukaryotic gene expression and cellular function, as evidenced by the numerous pathologies induced or modified by splicing alterations. Major recent advances have been made in understanding the structures and functions of the splicing machinery, in the description and classification of physiological and pathological isoforms and in the development of the first therapies for genetic diseases based on modulation of splicing. Here, we review this progress and discuss important remaining challenges, including predicting splice sites from genomic sequences, understanding the variety of molecular mechanisms and logic of splicing regulation, and harnessing this knowledge for probing gene function and disease aetiology and for the design of novel therapeutic approaches.
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Affiliation(s)
- Malgorzata Ewa Rogalska
- Genome Biology Program, Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Barcelona, Spain
| | - Claudia Vivori
- Genome Biology Program, Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Barcelona, Spain
- Department of Medicine and Life Sciences, Universitat Pompeu Fabra (UPF), Barcelona, Spain
- The Francis Crick Institute, London, UK
| | - Juan Valcárcel
- Genome Biology Program, Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Barcelona, Spain.
- Department of Medicine and Life Sciences, Universitat Pompeu Fabra (UPF), Barcelona, Spain.
- Institució Catalana de Recerca i Estudis Avançats (ICREA), Barcelona, Spain.
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14
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How does precursor RNA structure influence RNA processing and gene expression? Biosci Rep 2023; 43:232489. [PMID: 36689327 PMCID: PMC9977717 DOI: 10.1042/bsr20220149] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Revised: 01/17/2023] [Accepted: 01/23/2023] [Indexed: 01/24/2023] Open
Abstract
RNA is a fundamental biomolecule that has many purposes within cells. Due to its single-stranded and flexible nature, RNA naturally folds into complex and dynamic structures. Recent technological and computational advances have produced an explosion of RNA structural data. Many RNA structures have regulatory and functional properties. Studying the structure of nascent RNAs is particularly challenging due to their low abundance and long length, but their structures are important because they can influence RNA processing. Precursor RNA processing is a nexus of pathways that determines mature isoform composition and that controls gene expression. In this review, we examine what is known about human nascent RNA structure and the influence of RNA structure on processing of precursor RNAs. These known structures provide examples of how other nascent RNAs may be structured and show how novel RNA structures may influence RNA processing including splicing and polyadenylation. RNA structures can be targeted therapeutically to treat disease.
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15
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Ye R, Hu N, Cao C, Su R, Xu S, Yang C, Zhou X, Xue Y. Capture RIC-seq reveals positional rules of PTBP1-associated RNA loops in splicing regulation. Mol Cell 2023; 83:1311-1327.e7. [PMID: 36958328 DOI: 10.1016/j.molcel.2023.03.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2022] [Revised: 01/10/2023] [Accepted: 02/27/2023] [Indexed: 03/25/2023]
Abstract
RNA-binding proteins (RBPs) bind at different positions of the pre-mRNA molecules to promote or reduce the usage of a particular exon. Seeking to understand the working principle of these positional effects, we develop a capture RIC-seq (CRIC-seq) method to enrich specific RBP-associated in situ proximal RNA-RNA fragments for deep sequencing. We determine hnRNPA1-, SRSF1-, and PTBP1-associated proximal RNA-RNA contacts and regulatory mechanisms in HeLa cells. Unexpectedly, the 3D RNA map analysis shows that PTBP1-associated loops in individual introns preferentially promote cassette exon splicing by accelerating asymmetric intron removal, whereas the loops spanning across cassette exon primarily repress splicing. These "positional rules" can faithfully predict PTBP1-regulated splicing outcomes. We further demonstrate that cancer-related splicing quantitative trait loci can disrupt RNA loops by reducing PTBP1 binding on pre-mRNAs to cause aberrant splicing in tumors. Our study presents a powerful method for exploring the functions of RBP-associated RNA-RNA proximal contacts in gene regulation and disease.
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Affiliation(s)
- Rong Ye
- Key Laboratory of RNA Biology, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Naijing Hu
- Key Laboratory of RNA Biology, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Changchang Cao
- Key Laboratory of RNA Biology, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Ruibao Su
- Key Laboratory of RNA Biology, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Shihan Xu
- State Key Laboratory of Ophthalmology, Optometry and Vision Science, Wenzhou, Zhejiang 325003, China
| | - Chen Yang
- State Key Laboratory of Ophthalmology, Optometry and Vision Science, Wenzhou, Zhejiang 325003, China
| | - Xiangtian Zhou
- State Key Laboratory of Ophthalmology, Optometry and Vision Science, Wenzhou, Zhejiang 325003, China
| | - Yuanchao Xue
- Key Laboratory of RNA Biology, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China.
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16
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Wang KW, Riveros I, DeLoye J, Yildirim I. Dynamic docking of small molecules targeting RNA CUG repeats causing myotonic dystrophy type 1. Biophys J 2023; 122:180-196. [PMID: 36348626 PMCID: PMC9822796 DOI: 10.1016/j.bpj.2022.11.010] [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: 03/15/2022] [Revised: 08/05/2022] [Accepted: 11/04/2022] [Indexed: 11/09/2022] Open
Abstract
Expansion of RNA CUG repeats causes myotonic dystrophy type 1 (DM1). Once transcribed, the expanded CUG repeats strongly attract muscleblind-like 1 (MBNL1) proteins and disturb their functions in cells. Because of its unique structural form, expanded RNA CUG repeats are prospective drug targets, where small molecules can be utilized to target RNA CUG repeats to inhibit MBNL1 binding and ameliorate DM1-associated defects. In this contribution, we developed two physics-based dynamic docking approaches (DynaD and DynaD/Auto) and applied them to nine small molecules known to specifically target RNA CUG repeats. While DynaD uses a distance-based reaction coordinate to study the binding phenomenon, DynaD/Auto combines results of umbrella sampling calculations performed on 1 × 1 UU internal loops and AutoDock calculations to efficiently sample the energy landscape of binding. Predictions are compared with experimental data, displaying a positive correlation with correlation coefficient (R) values of 0.70 and 0.81 for DynaD and DynaD/Auto, respectively. Furthermore, we found that the best correlation was achieved with MM/3D-RISM calculations, highlighting the importance of solvation in binding calculations. Moreover, we detected that DynaD/Auto performed better than DynaD because of the use of prior knowledge about the binding site arising from umbrella sampling calculations. Finally, we developed dendrograms to present how bound states are connected to each other in a binding process. Results are exciting, as DynaD and DynaD/Auto will allow researchers to utilize two novel physics-based and computer-aided drug-design methodologies to perform in silico calculations on drug-like molecules aiming to target complex RNA loops.
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Affiliation(s)
- Kye Won Wang
- Department of Chemistry and Biochemistry, Florida Atlantic University, Jupiter, Florida; Departments of Biological Sciences and Chemistry, Lehigh University, Bethlehem, Pennsylvania
| | - Ivan Riveros
- Department of Chemistry and Biochemistry, Florida Atlantic University, Jupiter, Florida
| | - James DeLoye
- Department of Chemistry, University of California, Berkeley, Berkeley, California
| | - Ilyas Yildirim
- Department of Chemistry and Biochemistry, Florida Atlantic University, Jupiter, Florida.
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17
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Cognate RNA-Binding Modes by the Alternative-Splicing Regulator MBNL1 Inferred from Molecular Dynamics. Int J Mol Sci 2022; 23:ijms232416147. [PMID: 36555788 PMCID: PMC9780971 DOI: 10.3390/ijms232416147] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2022] [Revised: 12/06/2022] [Accepted: 12/15/2022] [Indexed: 12/23/2022] Open
Abstract
The muscleblind-like protein family (MBNL) plays a prominent role in the regulation of alternative splicing. Consequently, the loss of MBNL function resulting from sequestration by RNA hairpins triggers the development of a neuromuscular disease called myotonic dystrophy (DM). Despite the sequence and structural similarities between the four zinc-finger domains that form MBNL1, recent studies have revealed that the four binding domains have differentiated splicing activity. The dynamic behaviors of MBNL1 ZnFs were simulated using conventional molecular dynamics (cMD) and steered molecular dynamics (sMD) simulations of a structural model of MBNL1 protein to provide insights into the binding selectivity of the four zinc-finger (ZnF) domains toward the GpC steps in YGCY RNA sequence. In accordance with previous studies, our results suggest that both global and local residue fluctuations on each domain have great impacts on triggering alternative splicing, indicating that local motions in RNA-binding domains could modulate their affinity and specificity. In addition, all four ZnF domains provide a distinct RNA-binding environment in terms of structural sampling and mobility that may be involved in the differentiated MBNL1 splicing events reported in the literature.
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18
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Jones AN, Graß C, Meininger I, Geerlof A, Klostermann M, Zarnack K, Krappmann D, Sattler M. Modulation of pre-mRNA structure by hnRNP proteins regulates alternative splicing of MALT1. SCIENCE ADVANCES 2022; 8:eabp9153. [PMID: 35921415 PMCID: PMC9348792 DOI: 10.1126/sciadv.abp9153] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
Alternative splicing plays key roles for cell type-specific regulation of protein function. It is controlled by cis-regulatory RNA elements that are recognized by RNA binding proteins (RBPs). The MALT1 paracaspase is a key factor of signaling pathways that mediate innate and adaptive immune responses. Alternative splicing of MALT1 is critical for controlling optimal T cell activation. We demonstrate that MALT1 splicing depends on RNA structural elements that sequester the splice sites of the alternatively spliced exon7. The RBPs hnRNP U and hnRNP L bind competitively to stem-loop RNA structures that involve the 5' and 3' splice sites flanking exon7. While hnRNP U stabilizes RNA stem-loop conformations that maintain exon7 skipping, hnRNP L disrupts these RNA elements to facilitate recruitment of the essential splicing factor U2AF2, thereby promoting exon7 inclusion. Our data represent a paradigm for the control of splice site selection by differential RBP binding and modulation of pre-mRNA structure.
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Affiliation(s)
- Alisha N. Jones
- Institute of Structural Biology, Molecular Targets and Therapeutics Center, Helmholtz Zentrum München, Neuherberg, 85764 München, Germany
- Bavarian NMR Center, Department of Chemistry, Technical University of Munich, Garching, 85748 München, Germany
| | - Carina Graß
- Research Unit Cellular Signal Integration, Institute of Molecular Toxicology and Pharmacology, Molecular Targets and Therapeutics Center, Helmholtz Zentrum München, Neuherberg, 85764 München, Germany
| | - Isabel Meininger
- Research Unit Cellular Signal Integration, Institute of Molecular Toxicology and Pharmacology, Molecular Targets and Therapeutics Center, Helmholtz Zentrum München, Neuherberg, 85764 München, Germany
| | - Arie Geerlof
- Institute of Structural Biology, Molecular Targets and Therapeutics Center, Helmholtz Zentrum München, Neuherberg, 85764 München, Germany
| | - Melina Klostermann
- Buchmann Institute for Molecular Life Sciences (BMLS) & Faculty of Biological Sciences, Goethe University Frankfurt, Max-von-Laue-Str. 15, 60438 Frankfurt am Main, Germany
| | - Kathi Zarnack
- Buchmann Institute for Molecular Life Sciences (BMLS) & Faculty of Biological Sciences, Goethe University Frankfurt, Max-von-Laue-Str. 15, 60438 Frankfurt am Main, Germany
| | - Daniel Krappmann
- Research Unit Cellular Signal Integration, Institute of Molecular Toxicology and Pharmacology, Molecular Targets and Therapeutics Center, Helmholtz Zentrum München, Neuherberg, 85764 München, Germany
- Corresponding author. (D.K.); (M.S.)
| | - Michael Sattler
- Institute of Structural Biology, Molecular Targets and Therapeutics Center, Helmholtz Zentrum München, Neuherberg, 85764 München, Germany
- Bavarian NMR Center, Department of Chemistry, Technical University of Munich, Garching, 85748 München, Germany
- Corresponding author. (D.K.); (M.S.)
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19
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G R, Mitra A, Pk V. Predicting functional riboSNitches in the context of alternative splicing. Gene X 2022; 837:146694. [PMID: 35738445 DOI: 10.1016/j.gene.2022.146694] [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: 12/09/2021] [Revised: 05/11/2022] [Accepted: 06/17/2022] [Indexed: 11/19/2022] Open
Abstract
RNAs are the major regulators of gene expression, and their secondary structures play crucial roles at different levels. RiboSNitches are disease-associated SNPs that cause changes in the pre-mRNA secondary structural ensemble. Several riboSNitches have been detected in the 5' and 3' untranslated regions and lncRNA. Although cases of secondary structural elements playing a regulatory role in alternative splicing are known, regions specific to splicing events, such as splice junctions have not received much attention. We tested splice-site mutations for their efficiency in disrupting the secondary structure and hypothesized that these could play a crucial role in alternative splicing. Multiple riboSNitch prediction methods were applied to obtain overlapping results that are potentially more reliable. Putative riboSNitches were identified from aberrant 5' and 3' splice site mutations, cancer-causing somatic mutations, and genes that harbor the regulatory RNA secondary structural elements. Our workflow for predicting riboSNitches associated with alternative splicing is novel and paves the way for subsequent experimental validation.
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Affiliation(s)
- Ramya G
- Center for Computational Natural Sciences and Bioinformatics, International Institute of Information Technology, Gachibowli, Hyderabad, Telangana 500032, India.
| | - Abhijit Mitra
- Center for Computational Natural Sciences and Bioinformatics, International Institute of Information Technology, Gachibowli, Hyderabad, Telangana 500032, India.
| | - Vinod Pk
- Center for Computational Natural Sciences and Bioinformatics, International Institute of Information Technology, Gachibowli, Hyderabad, Telangana 500032, India.
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20
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Georgakopoulos-Soares I, Parada GE, Hemberg M. Secondary structures in RNA synthesis, splicing and translation. Comput Struct Biotechnol J 2022; 20:2871-2884. [PMID: 35765654 PMCID: PMC9198270 DOI: 10.1016/j.csbj.2022.05.041] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Revised: 05/19/2022] [Accepted: 05/21/2022] [Indexed: 11/30/2022] Open
Abstract
Even though the functional role of mRNA molecules is primarily decided by the nucleotide sequence, several properties are determined by secondary structure conformations. Examples of secondary structures include long range interactions, hairpins, R-loops and G-quadruplexes and they are formed through interactions of non-adjacent nucleotides. Here, we discuss advances in our understanding of how secondary structures can impact RNA synthesis, splicing, translation and mRNA half-life. During RNA synthesis, secondary structures determine RNA polymerase II (RNAPII) speed, thereby influencing splicing. Splicing is also determined by RNA binding proteins and their binding rates are modulated by secondary structures. For the initiation of translation, secondary structures can control the choice of translation start site. Here, we highlight the mechanisms by which secondary structures modulate these processes, discuss advances in technologies to detect and study them systematically, and consider the roles of RNA secondary structures in disease.
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21
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CircNCX1: the "Lord of the Ring" in the Heart - Insight into Its Sequence Characteristic, Expression, Molecular Mechanisms, and Clinical Application. J Cardiovasc Transl Res 2021; 15:571-586. [PMID: 34642871 DOI: 10.1007/s12265-021-10176-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Accepted: 09/20/2021] [Indexed: 12/21/2022]
Abstract
Circular RNAs (circRNAs) are covalently closed single-stranded RNAs with regulatory activity and regarded as new types of therapeutic targets in diseases such as cancers. By means of RNA-Seq technology, numerous cardiac circRNAs were discovered. Although some candidates were detected to involve in heart disease in murine model, relative low sequence conservation and expression level of their human homologs might result in an insignificant, even distinct effect in the human heart. Therefore, the therapeutic significance of circRNAs should be more strictly considered. It is also necessary to discuss which circRNA is suitable for being applied in heart disease treatment. Here, we are willing to introduce a ~ 1830 nt circular transcript generated from single exon of sodium/calcium exchanger 1 (ncx1) gene (also called solute carrier family 8 member A1, slc8a1), usually named circNCX1 or circSLC8A1, which is gradually coming into our view. circNCX1 is one of the most cardiac-enriched circRNAs. It is widely existent in vertebrate and relatively conserved, indicating its indispensability during the evolution of species. Indeed, circNCX1 was shown to involve in heart development by some expression analysis. It was further revealed that the dysregulation of circNCX1 is one of the key pathogeneses of heart diseases including ischemic cardiac injury and hypertrophic cardiomyopathy. To make the significance of circNCX1 in the heart clear, we comprehensively dissected circNCX1 in the aspects of its parental gene structure, conservation, biogenesis and expression profiles, function, molecular mechanisms, and clinical application in this review. New medicine or therapeutic schedules based on circNCX1 are expected in the future.
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22
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Biology of the mRNA Splicing Machinery and Its Dysregulation in Cancer Providing Therapeutic Opportunities. Int J Mol Sci 2021; 22:ijms22105110. [PMID: 34065983 PMCID: PMC8150589 DOI: 10.3390/ijms22105110] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Revised: 05/07/2021] [Accepted: 05/07/2021] [Indexed: 12/13/2022] Open
Abstract
Dysregulation of messenger RNA (mRNA) processing—in particular mRNA splicing—is a hallmark of cancer. Compared to normal cells, cancer cells frequently present aberrant mRNA splicing, which promotes cancer progression and treatment resistance. This hallmark provides opportunities for developing new targeted cancer treatments. Splicing of precursor mRNA into mature mRNA is executed by a dynamic complex of proteins and small RNAs called the spliceosome. Spliceosomes are part of the supraspliceosome, a macromolecular structure where all co-transcriptional mRNA processing activities in the cell nucleus are coordinated. Here we review the biology of the mRNA splicing machinery in the context of other mRNA processing activities in the supraspliceosome and present current knowledge of its dysregulation in lung cancer. In addition, we review investigations to discover therapeutic targets in the spliceosome and give an overview of inhibitors and modulators of the mRNA splicing process identified so far. Together, this provides insight into the value of targeting the spliceosome as a possible new treatment for lung cancer.
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23
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Liu Z, Liu Q, Yang X, Zhang Y, Norris M, Chen X, Cheema J, Zhang H, Ding Y. In vivo nuclear RNA structurome reveals RNA-structure regulation of mRNA processing in plants. Genome Biol 2021; 22:11. [PMID: 33397430 PMCID: PMC7784297 DOI: 10.1186/s13059-020-02236-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2020] [Accepted: 12/11/2020] [Indexed: 01/02/2023] Open
Abstract
BACKGROUND mRNA processing is critical for gene expression. A challenge in regulating mRNA processing is how to recognize the actual mRNA processing sites, such as splice and polyadenylation sites, when the sequence content is insufficient for this purpose. Previous studies suggested that RNA structure affects mRNA processing. However, the regulatory role of RNA structure in mRNA processing remains unclear. RESULTS Here, we perform in vivo selective 2'-hydroxyl acylation analyzed by primer extension (SHAPE) chemical profiling on Arabidopsis and generate the in vivo nuclear RNA structure landscape. We find that nuclear mRNAs fold differently from cytosolic mRNAs across translation start and stop sites. Notably, we discover a two-nucleotide single-stranded RNA structure feature upstream of 5' splice sites that is strongly associated with splicing and the selection of alternative 5' splice sites. The regulatory role of this RNA structure feature is further confirmed by experimental validation. Moreover, we find the single-strandedness of branch sites is also associated with 3' splice site recognition. We also identify an RNA structure feature comprising two close-by single-stranded regions that is specifically associated with both polyadenylation and alternative polyadenylation events. CONCLUSIONS We successfully identify pre-mRNA structure features associated with splicing and polyadenylation at whole-genome scale and validate an RNA structure feature which can regulate splicing. Our study unveils a new RNA structure regulatory mechanism for mRNA processing.
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Affiliation(s)
- Zhenshan Liu
- Department of Cell and Developmental Biology, John Innes Centre, Norwich Research Park, Norwich, NR4 7UH UK
| | - Qi Liu
- Department of Cell and Developmental Biology, John Innes Centre, Norwich Research Park, Norwich, NR4 7UH UK
| | - Xiaofei Yang
- Department of Cell and Developmental Biology, John Innes Centre, Norwich Research Park, Norwich, NR4 7UH UK
| | - Yueying Zhang
- Department of Cell and Developmental Biology, John Innes Centre, Norwich Research Park, Norwich, NR4 7UH UK
| | - Matthew Norris
- Department of Cell and Developmental Biology, John Innes Centre, Norwich Research Park, Norwich, NR4 7UH UK
| | - Xiaoxi Chen
- Department of Cell and Developmental Biology, John Innes Centre, Norwich Research Park, Norwich, NR4 7UH UK
| | - Jitender Cheema
- Department of Cell and Developmental Biology, John Innes Centre, Norwich Research Park, Norwich, NR4 7UH UK
| | - Huakun Zhang
- Key Laboratory of Molecular Epigenetics of the Ministry of Education, Northeast Normal University, Changchun, 130024 China
| | - Yiliang Ding
- Department of Cell and Developmental Biology, John Innes Centre, Norwich Research Park, Norwich, NR4 7UH UK
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24
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Bubenik JL, Hale M, McConnell O, Wang E, Swanson MS, Spitale R, Berglund JA. RNA structure probing to characterize RNA-protein interactions on a low abundance pre-mRNA in living cells. RNA (NEW YORK, N.Y.) 2020; 27:rna.077263.120. [PMID: 33310817 PMCID: PMC7901844 DOI: 10.1261/rna.077263.120] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/12/2020] [Accepted: 11/29/2020] [Indexed: 06/12/2023]
Abstract
In vivo RNA structure analysis has become a powerful tool in molecular biology, largely due to the coupling of an increasingly diverse set of chemical approaches with high-throughput sequencing. This has resulted in a transition from single target to transcriptome-wide approaches. However, these methods require sequencing depths that preclude studying low abundance targets, which are not sufficiently captured in transcriptome-wide approaches. Here we present a ligation-free method to enrich for low abundance RNA sequences, which improves the diversity of molecules analyzed and results in improved analysis. In addition, this method is compatible with any choice of chemical adduct or read-out approach. We utilized this approach to study an autoregulated event in the pre-mRNA of the splicing factor, muscleblind-like splicing regulator 1 (MBNL1).
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25
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Mechanisms of Long Noncoding RNA Nuclear Retention. Trends Biochem Sci 2020; 45:947-960. [DOI: 10.1016/j.tibs.2020.07.001] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Revised: 06/27/2020] [Accepted: 07/15/2020] [Indexed: 12/11/2022]
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26
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Taylor K, Sobczak K. Intrinsic Regulatory Role of RNA Structural Arrangement in Alternative Splicing Control. Int J Mol Sci 2020; 21:ijms21145161. [PMID: 32708277 PMCID: PMC7404189 DOI: 10.3390/ijms21145161] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Accepted: 07/17/2020] [Indexed: 12/14/2022] Open
Abstract
Alternative splicing is a highly sophisticated process, playing a significant role in posttranscriptional gene expression and underlying the diversity and complexity of organisms. Its regulation is multilayered, including an intrinsic role of RNA structural arrangement which undergoes time- and tissue-specific alterations. In this review, we describe the principles of RNA structural arrangement and briefly decipher its cis- and trans-acting cellular modulators which serve as crucial determinants of biological functionality of the RNA structure. Subsequently, we engage in a discussion about the RNA structure-mediated mechanisms of alternative splicing regulation. On one hand, the impairment of formation of optimal RNA structures may have critical consequences for the splicing outcome and further contribute to understanding the pathomechanism of severe disorders. On the other hand, the structural aspects of RNA became significant features taken into consideration in the endeavor of finding potential therapeutic treatments. Both aspects have been addressed by us emphasizing the importance of ongoing studies in both fields.
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27
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Hung CS, Lin JC. Alternatively spliced MBNL1 isoforms exhibit differential influence on enhancing brown adipogenesis. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2019; 1863:194437. [PMID: 31730826 DOI: 10.1016/j.bbagrm.2019.194437] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2019] [Revised: 09/23/2019] [Accepted: 09/25/2019] [Indexed: 01/15/2023]
Abstract
Browning of white adipocytes (WAs) (also referred as beige cells) was demonstrated to execute thermogenesis by consuming stored lipids as do brown adipocytes (BAs), and this is highly related to metabolic homeostasis. Alternative splicing (AS) constitutes a pivotal mechanism for defining cellular fates and functional specifications. Nevertheless, the impacts of AS regulation on the browning of WAs have not been comprehensively investigated. In this study, we first identified the discriminative expression and splicing profiles of the muscleblind-like 1 (MBNL1) gene in postnatal brown adipose tissues (BATs) compared to those of embryonic BATs. A shift in the MBNL1+ex 5 isoform 7 (MBNL17) to MBNL1-ex 5 isoform 1 (MBNL11) was characterized throughout BAT development or during the in vitro browning of pre-WAs, 3T3-L1 cells. The interplay between MBNL1 and the exonic CCUG motif constitutes an autoregulatory mechanism for excluding MBNL1 exon 5. The simultaneous association of RNA-binding motif protein 4a (RBM4a) with exonic and intronic CU elements collaboratively mediates the skipping of MBNL1 exon 5. Overexpressing the MBNL11 isoform exhibited a more-prominent effect than that of the MBNL17 isoform on programming its own transcripts and beige cell-related splicing events in a CCUG motif-mediated manner. In addition to splicing regulation, overexpression of the MBNL11 and MBNL17 isoforms differentially enhanced beige adipogenic signatures of 3T3-L1 cells. Our findings demonstrated that MBNL1 constitutes an emerging and autoregulatory mechanism involved in development of beige cells.
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Affiliation(s)
- Ching-Sheng Hung
- PhD Program in Medicine Biotechnology, College of Medical Science and Technology, Taipei Medical University, Taipei, Taiwan; Department of Laboratory Medicine, Wan Fang Hospital, Taipei Medical University, Taipei, Taiwan
| | - Jung-Chun Lin
- PhD Program in Medicine Biotechnology, College of Medical Science and Technology, Taipei Medical University, Taipei, Taiwan; School of Medical Laboratory Science and Biotechnology, College of Medical Science and Technology, Taipei Medical University, Taipei, Taiwan.
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28
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Neil CR, Fairbrother WG. Intronic RNA: Ad'junk' mediator of post-transcriptional gene regulation. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2019; 1862:194439. [PMID: 31682938 DOI: 10.1016/j.bbagrm.2019.194439] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/04/2019] [Accepted: 09/30/2019] [Indexed: 01/23/2023]
Abstract
RNA splicing, the process through which intervening segments of noncoding RNA (introns) are excised from pre-mRNAs to allow for the formation of a mature mRNA product, has long been appreciated for its capacity to add complexity to eukaryotic proteomes. However, evidence suggests that the utility of this process extends beyond protein output and provides cells with a dynamic tool for gene regulation. In this review, we aim to highlight the role that intronic RNA plays in mediating specific splicing outcomes in pre-mRNA processing, as well as explore an emerging class of stable intronic sequences that have been observed to act in gene expression control. Building from underlying flexibility in both sequence and structure, intronic RNA provides mechanisms for post-transcriptional gene regulation that are amenable to the tissue and condition specific needs of eukaryotic cells. This article is part of a Special Issue entitled: RNA structure and splicing regulation edited by Francisco Baralle, Ravindra Singh and Stefan Stamm.
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Affiliation(s)
- Christopher R Neil
- Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence, RI, United States of America
| | - William G Fairbrother
- Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence, RI, United States of America; Center for Computational Molecular Biology, Brown University, Providence, RI, United States of America.
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29
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Desterro J, Bak-Gordon P, Carmo-Fonseca M. Targeting mRNA processing as an anticancer strategy. Nat Rev Drug Discov 2019; 19:112-129. [PMID: 31554928 DOI: 10.1038/s41573-019-0042-3] [Citation(s) in RCA: 108] [Impact Index Per Article: 21.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/08/2019] [Indexed: 12/19/2022]
Abstract
Discoveries in the past decade have highlighted the potential of mRNA as a therapeutic target for cancer. Specifically, RNA sequencing revealed that, in addition to gene mutations, alterations in mRNA can contribute to the initiation and progression of cancer. Indeed, precursor mRNA processing, which includes the removal of introns by splicing and the formation of 3' ends by cleavage and polyadenylation, is frequently altered in tumours. These alterations result in numerous cancer-specific mRNAs that generate altered levels of normal proteins or proteins with new functions, leading to the activation of oncogenes or the inactivation of tumour-suppressor genes. Abnormally spliced and polyadenylated mRNAs are also associated with resistance to cancer treatment and, unexpectedly, certain cancers are highly sensitive to the pharmacological inhibition of splicing. This Review summarizes recent progress in our understanding of how splicing and polyadenylation are altered in cancer and highlights how this knowledge has been translated for drug discovery, resulting in the production of small molecules and oligonucleotides that modulate the spliceosome and are in clinical trials for the treatment of cancer.
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Affiliation(s)
- Joana Desterro
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal.,Instituto Português de Oncologia de Lisboa, Serviço de Hematologia, Lisboa, Portugal
| | - Pedro Bak-Gordon
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal
| | - Maria Carmo-Fonseca
- Instituto de Medicina Molecular João Lobo Antunes, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal.
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30
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Taylor K, Sznajder LJ, Cywoniuk P, Thomas JD, Swanson MS, Sobczak K. MBNL splicing activity depends on RNA binding site structural context. Nucleic Acids Res 2019; 46:9119-9133. [PMID: 29955876 PMCID: PMC6158504 DOI: 10.1093/nar/gky565] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2018] [Accepted: 06/16/2018] [Indexed: 02/02/2023] Open
Abstract
Muscleblind-like (MBNL) proteins are conserved RNA-binding factors involved in alternative splicing (AS) regulation during development. While AS is controlled by distribution of MBNL paralogs and isoforms, the affinity of these proteins for specific RNA-binding regions and their location within transcripts, it is currently unclear how RNA structure impacts MBNL-mediated AS regulation. Here, we defined the RNA structural determinants affecting MBNL-dependent AS activity using both cellular and biochemical assays. While enhanced inclusion of MBNL-regulated alternative exons is controlled by the arrangement and number of MBNL binding sites within unstructured RNA, when these sites are embedded in a RNA hairpin MBNL binds preferentially to one side of stem region. Surprisingly, binding of MBNL proteins to RNA targets did not entirely correlate with AS efficiency. Moreover, comparison of MBNL proteins revealed structure-dependent competitive behavior between the paralogs. Our results showed that the structure of targeted RNAs is a prevalent component of the mechanism of alternative splicing regulation by MBNLs.
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Affiliation(s)
- Katarzyna Taylor
- Laboratory of Gene Therapy, Department of Gene Expression, Institute of Molecular Biology and Biotechnology, Faculty of Biology, Adam Mickiewicz University, Umultowska 89, 61-614 Poznan, Poland
| | - Lukasz J Sznajder
- Center for NeuroGenetics and the Genetics Institute, Department of Molecular Genetics and Microbiology, University of Florida College of Medicine, 2033 Mowry Road, Gainesville, FL 32610, USA
| | - Piotr Cywoniuk
- Laboratory of Gene Therapy, Department of Gene Expression, Institute of Molecular Biology and Biotechnology, Faculty of Biology, Adam Mickiewicz University, Umultowska 89, 61-614 Poznan, Poland
| | - James D Thomas
- Center for NeuroGenetics and the Genetics Institute, Department of Molecular Genetics and Microbiology, University of Florida College of Medicine, 2033 Mowry Road, Gainesville, FL 32610, USA.,Computational Biology Program, Public Health Sciences Division, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
| | - Maurice S Swanson
- Center for NeuroGenetics and the Genetics Institute, Department of Molecular Genetics and Microbiology, University of Florida College of Medicine, 2033 Mowry Road, Gainesville, FL 32610, USA
| | - Krzysztof Sobczak
- Laboratory of Gene Therapy, Department of Gene Expression, Institute of Molecular Biology and Biotechnology, Faculty of Biology, Adam Mickiewicz University, Umultowska 89, 61-614 Poznan, Poland
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31
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Bartys N, Kierzek R, Lisowiec-Wachnicka J. The regulation properties of RNA secondary structure in alternative splicing. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2019; 1862:194401. [PMID: 31323437 DOI: 10.1016/j.bbagrm.2019.07.002] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Accepted: 07/09/2019] [Indexed: 11/30/2022]
Abstract
The RNA secondary structure is important for many functional processes in the cell. The secondary and tertiary structures of cellular RNAs are essential for the activity of these molecules in processes such as transcription, splicing, translation, and localization. New high-throughput analytical methods, including next generation sequencing, have allowed for the in-depth characterization of the 'RNA structurome': a new term describing how the RNA structure controls the activity of RNA by itself and how it regulates the expression of genes. In this review, we present many examples of the influence of structural motifs of RNA, long range interactions and global RNA structure on the alternative splicing processes. This article is part of a Special Issue entitled: RNA structure and splicing regulation edited by Francisco Baralle, Ravindra Singh and Stefan Stamm.
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Affiliation(s)
- Natalia Bartys
- Institute of Bioorganic Chemistry, Polish Academy of Sciences, Z. Noskowskiego 12/14, 61-704 Poznań, Poland
| | - Ryszard Kierzek
- Institute of Bioorganic Chemistry, Polish Academy of Sciences, Z. Noskowskiego 12/14, 61-704 Poznań, Poland
| | - Jolanta Lisowiec-Wachnicka
- Institute of Bioorganic Chemistry, Polish Academy of Sciences, Z. Noskowskiego 12/14, 61-704 Poznań, Poland.
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32
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Hale MA, Johnson NE, Berglund JA. Repeat-associated RNA structure and aberrant splicing. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2019; 1862:194405. [PMID: 31323433 DOI: 10.1016/j.bbagrm.2019.07.006] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/2019] [Revised: 07/11/2019] [Accepted: 07/12/2019] [Indexed: 12/13/2022]
Abstract
Over 30 hereditary disorders attributed to the expansion of microsatellite repeats have been identified. Despite variant nucleotide content, number of consecutive repeats, and different locations in the genome, many of these diseases have pathogenic RNA gain-of-function mechanisms. The repeat-containing RNAs can form structures in vitro predicted to contribute to the disease through assembly of intracellular RNA aggregates termed foci. The expanded repeat RNAs within these foci sequester RNA binding proteins (RBPs) with important roles in the regulation of RNA metabolism, most notably alternative splicing (AS). These deleterious interactions lead to downstream alterations in transcriptome-wide AS directly linked with disease symptoms. This review summarizes existing knowledge about the association between the repeat RNA structures and RBPs as well as the resulting aberrant AS patterns, specifically in the context of myotonic dystrophy. The connection between toxic, structured RNAs and dysregulation of AS in other repeat expansion diseases is also discussed. This article is part of a Special Issue entitled: RNA structure and splicing regulation edited by Francisco Baralle, Ravindra Singh and Stefan Stamm.
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Affiliation(s)
- Melissa A Hale
- Department of Neurology, Virginia Commonwealth University, Richmond, VA 23298, USA
| | - Nicholas E Johnson
- Department of Neurology, Virginia Commonwealth University, Richmond, VA 23298, USA
| | - J Andrew Berglund
- The RNA Institute, Department of Biological Sciences, University at Albany, State University of New York, Albany, NY 12222, USA.
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33
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Gasiūnienė M, Zentelytė A, Wojtas B, Baronaitė S, Krasovskaja N, Savickienė J, Gielniewski B, Kaminska B, Utkus A, Navakauskienė R. DNA methyltransferases inhibitors effectively induce gene expression changes suggestive of cardiomyogenic differentiation of human amniotic fluid-derived mesenchymal stem cells via chromatin remodeling. J Tissue Eng Regen Med 2019; 13:469-481. [PMID: 30637987 DOI: 10.1002/term.2800] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2017] [Revised: 10/31/2018] [Accepted: 01/09/2019] [Indexed: 12/17/2022]
Abstract
Human amniotic fluid-derived mesenchymal stem cells (AF-MSCs) are a new potential stem cell source for cell therapy and regenerative medicine. These are fetal mesenchymal stem cells with multilineage differentiation potential found in amniotic fluid. The aim of the present study was to evaluate in vitro differentiation initiation of AF-MSCs into cardiac progenitors upon application of inhibitors of DNA methyltransferases (DNMT), such as Decitabine (DEC; 5-aza-2'-deoxycytidine) and Zebularine (ZEB). We assessed epigenetic changes and explored patterns of genes, enriched in association with hyperacetylated H4 after induced differentiation. Upregulation of cardiomyogenesis-related genes (TNNT2, MYH6, ACTN2, and DES) and cardiac ion channels genes, downregulation of pluripotency genes markers as well as increase in Connexin43 expression indicated cardiomyogenic commitment. Evaluation of global epigenetic changes showed that levels of chromatin modifying enzymes, such as Polycomb repressive complex 2 proteins (EZH2, SUZ12), DNMT1, histone deacetylases 1 and 2 were reduced to the similar extent by both differentiation agents. Levels of specific histone marks keeping active state of chromatin (H3K4me3, H3K9Ac, and H4hyperAc) increased and marks of repressed chromatin state (H3K27me3 and H3K9me3) decreased after DEC or ZEB treatment. Chip-Seq analysis after chromatin immunoprecipitation with H4hyperAc demonstrated enrichment of around 100 functionally annotated genes, related to chromatin reorganization and cardiomyogenesis and confirmed relation between H4 hyperacetylation and gene expression. Our results demonstrate that both DEC and ZEB can be potentially used as cardiomyogenic differentiation inducers in AF-MSCs, and they cause various genetic and epigenetic changes resulting in global chromatin remodeling.
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Affiliation(s)
- Monika Gasiūnienė
- Institute of Biochemistry, Life Sciences Center, Vilnius University, Vilnius, Lithuania
| | - Aistė Zentelytė
- Institute of Biochemistry, Life Sciences Center, Vilnius University, Vilnius, Lithuania
| | - Bartosz Wojtas
- Laboratory of Molecular Neurobiology, Nencki Institute of Experimental Biology, Warsaw, Poland
| | - Sandra Baronaitė
- Institute of Biochemistry, Life Sciences Center, Vilnius University, Vilnius, Lithuania
| | | | - Jūratė Savickienė
- Institute of Biochemistry, Life Sciences Center, Vilnius University, Vilnius, Lithuania
| | - Bartlomiej Gielniewski
- Laboratory of Molecular Neurobiology, Nencki Institute of Experimental Biology, Warsaw, Poland
| | - Bozena Kaminska
- Laboratory of Molecular Neurobiology, Nencki Institute of Experimental Biology, Warsaw, Poland
| | - Algirdas Utkus
- Faculty of Medicine, Vilnius University, Vilnius, Lithuania
| | - Rūta Navakauskienė
- Institute of Biochemistry, Life Sciences Center, Vilnius University, Vilnius, Lithuania
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34
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Zhao J, Harris ME. Distributive enzyme binding controlled by local RNA context results in 3' to 5' directional processing of dicistronic tRNA precursors by Escherichia coli ribonuclease P. Nucleic Acids Res 2019; 47:1451-1467. [PMID: 30496557 PMCID: PMC6379654 DOI: 10.1093/nar/gky1162] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2018] [Revised: 10/17/2018] [Accepted: 11/11/2018] [Indexed: 12/16/2022] Open
Abstract
RNA processing by ribonucleases and RNA modifying enzymes often involves sequential reactions of the same enzyme on a single precursor transcript. In Escherichia coli, processing of polycistronic tRNA precursors involves separation into individual pre-tRNAs by one of several ribonucleases followed by 5′ end maturation by ribonuclease P. A notable exception are valine and lysine tRNAs encoded by three polycistronic precursors that follow a recently discovered pathway involving initial 3′ to 5′ directional processing by RNase P. Here, we show that the dicistronic precursor containing tRNAvalV and tRNAvalW undergoes accurate and efficient 3′ to 5′ directional processing by RNase P in vitro. Kinetic analyses reveal a distributive mechanism involving dissociation of the enzyme between the two cleavage steps. Directional processing is maintained despite swapping or duplicating the two tRNAs consistent with inhibition of processing by 3′ trailer sequences. Structure-function studies identify a stem–loop in 5′ leader of tRNAvalV that inhibits RNase P cleavage and further enforces directional processing. The results demonstrate that directional processing is an intrinsic property of RNase P and show how RNA sequence and structure context can modulate reaction rates in order to direct precursors along specific pathways.
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Affiliation(s)
- Jing Zhao
- Department of Chemistry, University of Florida, Gainesville, FL 32603, USA
| | - Michael E Harris
- Department of Chemistry, University of Florida, Gainesville, FL 32603, USA
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35
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Tabaglio T, Low DH, Teo WKL, Goy PA, Cywoniuk P, Wollmann H, Ho J, Tan D, Aw J, Pavesi A, Sobczak K, Wee DKB, Guccione E. MBNL1 alternative splicing isoforms play opposing roles in cancer. Life Sci Alliance 2018; 1:e201800157. [PMID: 30456384 PMCID: PMC6238595 DOI: 10.26508/lsa.201800157] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2018] [Revised: 08/27/2018] [Accepted: 08/29/2018] [Indexed: 12/20/2022] Open
Abstract
MBNL1 proteins lacking exon 7 (−ex7) are antisurvival factors with tumor suppressive role that cancer cells tend to down-regulate in favor of MBNL +ex7 isoforms. The extent of and the oncogenic role played by alternative splicing (AS) in cancer are well documented. Nonetheless, only few studies have attempted to dissect individual gene function at an isoform level. Here, we focus on the AS of splicing factors during prostate cancer progression, as these factors are known to undergo extensive AS and have the potential to affect hundreds of downstream genes. We identified exon 7 (ex7) in the MBNL1 (Muscleblind-like 1) transcript as being the most differentially included exon in cancer, both in cell lines and in patients' samples. In contrast, MBNL1 overall expression was down-regulated, consistently with its described role as a tumor suppressor. This observation holds true in the majority of cancer types analyzed. We first identified components associated to the U2 splicing complex (SF3B1, SF3A1, and PHF5A) as required for efficient ex7 inclusion and we confirmed that this exon is fundamental for MBNL1 protein homodimerization. We next used splice-switching antisense oligonucleotides (AONs) or siRNAs to compare the effect of MBNL1 splicing isoform switching with knockdown. We report that whereas the absence of MBNL1 is tolerated in cancer cells, the expression of isoforms lacking ex7 (MBNL1 Δex7) induces DNA damage and inhibits cell viability and migration, acting as dominant negative proteins. Our data demonstrate the importance of studying gene function at the level of alternative spliced isoforms and support our conclusion that MBNL1 Δex7 proteins are antisurvival factors with a defined tumor suppressive role that cancer cells tend to down-regulate in favor of MBNL +ex7 isoforms.
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Affiliation(s)
- Tommaso Tabaglio
- Institute of Molecular and Cell Biology, Agency for Science, Technology and Research, Singapore.,Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Diana Hp Low
- Institute of Molecular and Cell Biology, Agency for Science, Technology and Research, Singapore.,Cancer Science Institute, Singapore
| | - Winnie Koon Lay Teo
- Institute of Molecular and Cell Biology, Agency for Science, Technology and Research, Singapore
| | - Pierre Alexis Goy
- Institute of Molecular and Cell Biology, Agency for Science, Technology and Research, Singapore.,Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Piotr Cywoniuk
- Department of Gene Expression, Institute of Molecular Biology and Biotechnology, Adam Mickiewicz University, Poznan, Poland
| | - Heike Wollmann
- Institute of Molecular and Cell Biology, Agency for Science, Technology and Research, Singapore
| | - Jessica Ho
- Institute of Molecular and Cell Biology, Agency for Science, Technology and Research, Singapore
| | - Damien Tan
- Institute of Molecular and Cell Biology, Agency for Science, Technology and Research, Singapore
| | - Joey Aw
- Institute of Molecular and Cell Biology, Agency for Science, Technology and Research, Singapore
| | - Andrea Pavesi
- Institute of Molecular and Cell Biology, Agency for Science, Technology and Research, Singapore
| | - Krzysztof Sobczak
- Department of Gene Expression, Institute of Molecular Biology and Biotechnology, Adam Mickiewicz University, Poznan, Poland
| | - Dave Keng Boon Wee
- Institute of High Performance Computing, Agency for Science, Technology and Research, Singapore.,Bioinformatics Institute, Agency for Science, Technology and Research, Singapore
| | - Ernesto Guccione
- Institute of Molecular and Cell Biology, Agency for Science, Technology and Research, Singapore.,Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore.,Cancer Science Institute, Singapore.,National Cancer Centre Singapore, Singapore.,Department of Oncological Sciences, Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, New York, NY, USA
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36
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Dvinge H. Regulation of alternative
mRNA
splicing: old players and new perspectives. FEBS Lett 2018; 592:2987-3006. [DOI: 10.1002/1873-3468.13119] [Citation(s) in RCA: 54] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2018] [Revised: 05/23/2018] [Accepted: 05/29/2018] [Indexed: 12/22/2022]
Affiliation(s)
- Heidi Dvinge
- Department of Biomolecular Chemistry School of Medicine and Public Health University of Wisconsin‐Madison WI USA
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37
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Dominguez D, Freese P, Alexis MS, Su A, Hochman M, Palden T, Bazile C, Lambert NJ, Van Nostrand EL, Pratt GA, Yeo GW, Graveley BR, Burge CB. Sequence, Structure, and Context Preferences of Human RNA Binding Proteins. Mol Cell 2018; 70:854-867.e9. [PMID: 29883606 PMCID: PMC6062212 DOI: 10.1016/j.molcel.2018.05.001] [Citation(s) in RCA: 291] [Impact Index Per Article: 48.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2017] [Revised: 03/20/2018] [Accepted: 05/01/2018] [Indexed: 01/03/2023]
Abstract
RNA binding proteins (RBPs) orchestrate the production, processing, and function of mRNAs. Here, we present the affinity landscapes of 78 human RBPs using an unbiased assay that determines the sequence, structure, and context preferences of these proteins in vitro by deep sequencing of bound RNAs. These data enable construction of "RNA maps" of RBP activity without requiring crosslinking-based assays. We found an unexpectedly low diversity of RNA motifs, implying frequent convergence of binding specificity toward a relatively small set of RNA motifs, many with low compositional complexity. Offsetting this trend, however, we observed extensive preferences for contextual features distinct from short linear RNA motifs, including spaced "bipartite" motifs, biased flanking nucleotide composition, and bias away from or toward RNA structure. Our results emphasize the importance of contextual features in RNA recognition, which likely enable targeting of distinct subsets of transcripts by different RBPs that recognize the same linear motif.
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Affiliation(s)
| | - Peter Freese
- Program in Computational and Systems Biology, MIT, Cambridge, MA, USA
| | - Maria S Alexis
- Program in Computational and Systems Biology, MIT, Cambridge, MA, USA
| | - Amanda Su
- Department of Biology, MIT, Cambridge, MA, USA
| | | | | | | | | | - Eric L Van Nostrand
- Department of Cellular and Molecular Medicine, University of California at San Diego, La Jolla, CA, USA; Institute for Genomic Medicine, University of California at San Diego, La Jolla, CA, USA
| | - Gabriel A Pratt
- Department of Cellular and Molecular Medicine, University of California at San Diego, La Jolla, CA, USA; Institute for Genomic Medicine, University of California at San Diego, La Jolla, CA, USA; Bioinformatics and Systems Biology Graduate Program, University of California at San Diego, La Jolla, CA, USA
| | - Gene W Yeo
- Department of Cellular and Molecular Medicine, University of California at San Diego, La Jolla, CA, USA; Institute for Genomic Medicine, University of California at San Diego, La Jolla, CA, USA; Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore; Molecular Engineering Laboratory, A(∗)STAR, Singapore, Singapore
| | - Brenton R Graveley
- Department of Genetics and Genome Sciences, Institute for Systems Genomics, University of Connecticut Health, Farmington, CT, USA
| | - Christopher B Burge
- Department of Biology, MIT, Cambridge, MA, USA; Department of Biological Engineering, MIT, Cambridge, MA, USA.
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38
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Sutandy FXR, Ebersberger S, Huang L, Busch A, Bach M, Kang HS, Fallmann J, Maticzka D, Backofen R, Stadler PF, Zarnack K, Sattler M, Legewie S, König J. In vitro iCLIP-based modeling uncovers how the splicing factor U2AF2 relies on regulation by cofactors. Genome Res 2018; 28:699-713. [PMID: 29643205 PMCID: PMC5932610 DOI: 10.1101/gr.229757.117] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2017] [Accepted: 02/09/2018] [Indexed: 01/26/2023]
Abstract
Alternative splicing generates distinct mRNA isoforms and is crucial for proteome diversity in eukaryotes. The RNA-binding protein (RBP) U2AF2 is central to splicing decisions, as it recognizes 3′ splice sites and recruits the spliceosome. We establish “in vitro iCLIP” experiments, in which recombinant RBPs are incubated with long transcripts, to study how U2AF2 recognizes RNA sequences and how this is modulated by trans-acting RBPs. We measure U2AF2 affinities at hundreds of binding sites and compare in vitro and in vivo binding landscapes by mathematical modeling. We find that trans-acting RBPs extensively regulate U2AF2 binding in vivo, including enhanced recruitment to 3′ splice sites and clearance of introns. Using machine learning, we identify and experimentally validate novel trans-acting RBPs (including FUBP1, CELF6, and PCBP1) that modulate U2AF2 binding and affect splicing outcomes. Our study offers a blueprint for the high-throughput characterization of in vitro mRNP assembly and in vivo splicing regulation.
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Affiliation(s)
| | | | - Lu Huang
- Institute of Molecular Biology (IMB) gGmbH, 55128 Mainz, Germany
| | - Anke Busch
- Institute of Molecular Biology (IMB) gGmbH, 55128 Mainz, Germany
| | - Maximilian Bach
- Institute of Molecular Biology (IMB) gGmbH, 55128 Mainz, Germany
| | - Hyun-Seo Kang
- Institute of Structural Biology, Helmholtz Center Munich, 85764 Neuherberg, Germany.,Biomolecular NMR and Center for Integrated Protein Science Munich at Department of Chemistry, Technical University of Munich, 85747 Garching, Germany
| | - Jörg Fallmann
- Bioinformatics Group, Department of Computer Science and Interdisciplinary Center for Bioinformatics, University of Leipzig, 04107 Leipzig, Germany
| | - Daniel Maticzka
- Bioinformatics Group, Department of Computer Science, University of Freiburg, 79110 Freiburg, Germany
| | - Rolf Backofen
- Bioinformatics Group, Department of Computer Science, University of Freiburg, 79110 Freiburg, Germany.,Centre for Biological Signalling Studies (BIOSS), University of Freiburg, 79104 Freiburg, Germany
| | - Peter F Stadler
- Bioinformatics Group, Department of Computer Science and Interdisciplinary Center for Bioinformatics, University of Leipzig, 04107 Leipzig, Germany
| | - Kathi Zarnack
- Buchmann Institute for Molecular Life Sciences (BMLS), Goethe University Frankfurt, 60438 Frankfurt a.M., Germany
| | - Michael Sattler
- Institute of Structural Biology, Helmholtz Center Munich, 85764 Neuherberg, Germany.,Biomolecular NMR and Center for Integrated Protein Science Munich at Department of Chemistry, Technical University of Munich, 85747 Garching, Germany
| | - Stefan Legewie
- Institute of Molecular Biology (IMB) gGmbH, 55128 Mainz, Germany
| | - Julian König
- Institute of Molecular Biology (IMB) gGmbH, 55128 Mainz, Germany
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39
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Muscle-Specific Mis-Splicing and Heart Disease Exemplified by RBM20. Genes (Basel) 2018; 9:genes9010018. [PMID: 29304022 PMCID: PMC5793171 DOI: 10.3390/genes9010018] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2017] [Revised: 12/23/2017] [Accepted: 12/27/2017] [Indexed: 11/17/2022] Open
Abstract
Alternative splicing is an essential post-transcriptional process to generate multiple functional RNAs or proteins from a single transcript. Progress in RNA biology has led to a better understanding of muscle-specific RNA splicing in heart disease. The recent discovery of the muscle-specific splicing factor RNA-binding motif 20 (RBM20) not only provided great insights into the general alternative splicing mechanism but also demonstrated molecular mechanism of how this splicing factor is associated with dilated cardiomyopathy. Here, we review our current knowledge of muscle-specific splicing factors and heart disease, with an emphasis on RBM20 and its targets, RBM20-dependent alternative splicing mechanism, RBM20 disease origin in induced Pluripotent Stem Cells (iPSCs), and RBM20 mutations in dilated cardiomyopathy. In the end, we will discuss the multifunctional role of RBM20 and manipulation of RBM20 as a potential therapeutic target for heart disease.
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40
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Cywoniuk P, Taylor K, Sznajder ŁJ, Sobczak K. Hybrid splicing minigene and antisense oligonucleotides as efficient tools to determine functional protein/RNA interactions. Sci Rep 2017; 7:17587. [PMID: 29242583 PMCID: PMC5730568 DOI: 10.1038/s41598-017-17816-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2017] [Accepted: 12/01/2017] [Indexed: 12/16/2022] Open
Abstract
Alternative splicing is a complex process that provides a high diversity of proteins from a limited number of protein-coding genes. It is governed by multiple regulatory factors, including RNA-binding proteins (RBPs), that bind to specific RNA sequences embedded in a specific structure. The ability to predict RNA-binding regions recognized by RBPs using whole-transcriptome approaches can deliver a multitude of data, including false-positive hits. Therefore, validation of the global results is indispensable. Here, we report the development of an efficient and rapid approach based on a modular hybrid minigene combined with antisense oligonucleotides to enable verification of functional RBP-binding sites within intronic and exonic sequences of regulated pre-mRNA. This approach also provides valuable information regarding the regulatory properties of pre-mRNA, including the RNA secondary structure context. We also show that the developed approach can be used to effectively identify or better characterize the inhibitory properties of potential therapeutic agents for myotonic dystrophy, which is caused by sequestration of specific RBPs, known as muscleblind-like proteins, by mutated RNA with expanded CUG repeats.
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Affiliation(s)
- Piotr Cywoniuk
- Department of Gene Expression, Institute of Molecular Biology and Biotechnology, Faculty of Biology, Adam Mickiewicz University, 61-614, Poznan, Poland
| | - Katarzyna Taylor
- Department of Gene Expression, Institute of Molecular Biology and Biotechnology, Faculty of Biology, Adam Mickiewicz University, 61-614, Poznan, Poland
| | - Łukasz J Sznajder
- Department of Gene Expression, Institute of Molecular Biology and Biotechnology, Faculty of Biology, Adam Mickiewicz University, 61-614, Poznan, Poland.,Center for NeuroGenetics and the Genetics Institute, Department of Molecular Genetics and Microbiology, College of Medicine, University of Florida,, Gainesville, Florida, 32610-3610, USA
| | - Krzysztof Sobczak
- Department of Gene Expression, Institute of Molecular Biology and Biotechnology, Faculty of Biology, Adam Mickiewicz University, 61-614, Poznan, Poland.
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41
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Ramanouskaya TV, Grinev VV. The determinants of alternative RNA splicing in human cells. Mol Genet Genomics 2017; 292:1175-1195. [PMID: 28707092 DOI: 10.1007/s00438-017-1350-0] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2017] [Accepted: 07/06/2017] [Indexed: 12/29/2022]
Abstract
Alternative splicing represents an important level of the regulation of gene function in eukaryotic organisms. It plays a critical role in virtually every biological process within an organism, including regulation of cell division and cell death, differentiation of tissues in the embryo and the adult organism, as well as in cellular response to diverse environmental factors. In turn, studies of the last decade have shown that alternative splicing itself is controlled by different mechanisms. Unfortunately, there is no clear understanding of how these diverse mechanisms, or determinants, regulate and constrain the set of alternative RNA species produced from any particular gene in every cell of the human body. Here, we provide a consolidated overview of alternative splicing determinants including RNA-protein interactions, epigenetic regulation via chromatin remodeling, coupling of transcription-to-alternative splicing, effect of secondary structures in pre-RNA, and function of the RNA quality control systems. We also extensively and critically discuss some mechanistic insights on coordinated inclusion/exclusion of exons during the formation of mature RNA molecules. We conclude that the final structure of RNA is pre-determined by a complex interplay between cis- and trans-acting factors. Altogether, currently available empirical data significantly expand our understanding of the functioning of the alternative splicing machinery of cells in normal and pathological conditions. On the other hand, there are still many blind spots that require further deep investigations.
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42
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Liu Z, Yuan G, Liu S, Jia J, Cheng L, Qi D, Shen S, Peng X, Liu G. Identified of a novel cis-element regulating the alternative splicing of LcDREB2. Sci Rep 2017; 7:46106. [PMID: 28383047 PMCID: PMC5382683 DOI: 10.1038/srep46106] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2016] [Accepted: 03/08/2017] [Indexed: 01/26/2023] Open
Abstract
Alternative splicing (AS) is an important gene regulation mechanism in plants. Despite the widespread use of AS in plant gene expression regulation, the identification of the cis-elements involved in the AS mechanism is rarely reported in plants. To explore the regulation mechanism of the AS of LcDREB2, a DREB2 ortholog from Sheepgrass (Leymus chinensis), the genomic sequences of LcDREB2 and its homologs in Poaceae were aligned, and six mutations were introduced in the conserved sequence of LcDREB2. By analyzing the distinct transcript patterns of the LcDREB2 mutants in transgenic Oryza sativa, a novel cis-element that affected the AS of LcDREB2 was identified as Exonic Splicing Enhancer 1 (ESE1). In addition, five serine-arginine rich (SR) proteins were confirmed to interact with ESE1 by electrophoretic mobility shift assay (EMSA). To further explore the expression regulation mechanism of the DREB subfamily, phylogenetic analysis of DREB2 paralogous genes was performed. The results strongly supported the hypothesis that AS is conserved in Poaceae plants and that it is an evolutionary strategy for the regulation of the functional expression of genes. The findings and methods of our study will promote a substantial step forward in understanding of the plant AS regulation mechanism.
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Affiliation(s)
- Zhujiang Liu
- Key Laboratory of Plant Resources, Institute of Botany, the Chinese Academy of Sciences, Beijing, 100093, People's Republic of China.,University of the Chinese Academy of Sciences, Beijing, 100049, People's Republic of China
| | - Guangxiao Yuan
- Key Laboratory of Plant Resources, Institute of Botany, the Chinese Academy of Sciences, Beijing, 100093, People's Republic of China.,University of the Chinese Academy of Sciences, Beijing, 100049, People's Republic of China
| | - Shu Liu
- Key Laboratory of Plant Resources, Institute of Botany, the Chinese Academy of Sciences, Beijing, 100093, People's Republic of China.,University of the Chinese Academy of Sciences, Beijing, 100049, People's Republic of China
| | - Junting Jia
- Key Laboratory of Plant Resources, Institute of Botany, the Chinese Academy of Sciences, Beijing, 100093, People's Republic of China.,University of the Chinese Academy of Sciences, Beijing, 100049, People's Republic of China
| | - Liqin Cheng
- Key Laboratory of Plant Resources, Institute of Botany, the Chinese Academy of Sciences, Beijing, 100093, People's Republic of China
| | - Dongmei Qi
- Key Laboratory of Plant Resources, Institute of Botany, the Chinese Academy of Sciences, Beijing, 100093, People's Republic of China
| | - Shihua Shen
- Key Laboratory of Plant Resources, Institute of Botany, the Chinese Academy of Sciences, Beijing, 100093, People's Republic of China
| | - Xianjun Peng
- Key Laboratory of Plant Resources, Institute of Botany, the Chinese Academy of Sciences, Beijing, 100093, People's Republic of China
| | - Gongshe Liu
- Key Laboratory of Plant Resources, Institute of Botany, the Chinese Academy of Sciences, Beijing, 100093, People's Republic of China
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43
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Gallego-Paez LM, Bordone MC, Leote AC, Saraiva-Agostinho N, Ascensão-Ferreira M, Barbosa-Morais NL. Alternative splicing: the pledge, the turn, and the prestige : The key role of alternative splicing in human biological systems. Hum Genet 2017; 136:1015-1042. [PMID: 28374191 PMCID: PMC5602094 DOI: 10.1007/s00439-017-1790-y] [Citation(s) in RCA: 85] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2017] [Accepted: 03/25/2017] [Indexed: 02/06/2023]
Abstract
Alternative pre-mRNA splicing is a tightly controlled process conducted by the spliceosome, with the assistance of several regulators, resulting in the expression of different transcript isoforms from the same gene and increasing both transcriptome and proteome complexity. The differences between alternative isoforms may be subtle but enough to change the function or localization of the translated proteins. A fine control of the isoform balance is, therefore, needed throughout developmental stages and adult tissues or physiological conditions and it does not come as a surprise that several diseases are caused by its deregulation. In this review, we aim to bring the splicing machinery on stage and raise the curtain on its mechanisms and regulation throughout several systems and tissues of the human body, from neurodevelopment to the interactions with the human microbiome. We discuss, on one hand, the essential role of alternative splicing in assuring tissue function, diversity, and swiftness of response in these systems or tissues, and on the other hand, what goes wrong when its regulatory mechanisms fail. We also focus on the possibilities that splicing modulation therapies open for the future of personalized medicine, along with the leading techniques in this field. The final act of the spliceosome, however, is yet to be fully revealed, as more knowledge is needed regarding the complex regulatory network that coordinates alternative splicing and how its dysfunction leads to disease.
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Affiliation(s)
- L M Gallego-Paez
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal
| | - M C Bordone
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal
| | - A C Leote
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal
| | - N Saraiva-Agostinho
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal
| | - M Ascensão-Ferreira
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal
| | - N L Barbosa-Morais
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, Lisboa, Portugal.
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44
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LOX-1 and Its Splice Variants: A New Challenge for Atherosclerosis and Cancer-Targeted Therapies. Int J Mol Sci 2017; 18:ijms18020290. [PMID: 28146073 PMCID: PMC5343826 DOI: 10.3390/ijms18020290] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2016] [Revised: 01/15/2017] [Accepted: 01/23/2017] [Indexed: 12/13/2022] Open
Abstract
Alternative splicing (AS) is a process in which precursor messenger RNA (pre-mRNA) splicing sites are differentially selected to diversify the protein isoform population. Changes in AS patterns have an essential role in normal development, differentiation and response to physiological stimuli. It is documented that AS can generate both “risk” and “protective” splice variants that can contribute to the pathogenesis of several diseases including atherosclerosis. The main endothelial receptor for oxidized low-density lipoprotein (ox-LDLs) is LOX-1 receptor protein encoded by the OLR1 gene. When OLR1 undergoes AS events, it generates three variants: OLR1, OLR1D4 and LOXIN. The latter lacks exon 5 and two-thirds of the functional domain. Literature data demonstrate a protective role of LOXIN in pathologies correlated with LOX-1 overexpression such as atherosclerosis and tumors. In this review, we summarize recent developments in understanding of OLR1 AS while also highlighting data warranting further investigation of this process as a novel therapeutic target.
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45
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46
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Zhu C, Chen Z, Guo W. Pre-mRNA mis-splicing of sarcomeric genes in heart failure. Biochim Biophys Acta Mol Basis Dis 2016; 1863:2056-2063. [PMID: 27825848 DOI: 10.1016/j.bbadis.2016.11.008] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2016] [Revised: 10/11/2016] [Accepted: 11/01/2016] [Indexed: 12/01/2022]
Abstract
Pre-mRNA splicing is an important biological process that allows production of multiple proteins from a single gene in the genome, and mainly contributes to protein diversity in eukaryotic organisms. Alternative splicing is commonly governed by RNA binding proteins to meet the ever-changing demands of the cell. However, the mis-splicing may lead to human diseases. In the heart of human, mis-regulation of alternative splicing has been associated with heart failure. In this short review, we focus on alternative splicing of sarcomeric genes and review mis-splicing related heart failure with relatively well studied Sarcomeric genes and splicing mechanisms with identified regulatory factors. The perspective of alternative splicing based therapeutic strategies in heart failure has also been discussed.
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Affiliation(s)
- Chaoqun Zhu
- Animal Science, College of Agriculture and Natural Resources, University of Wyoming, Laramie, WY 82071, USA
| | - Zhilong Chen
- Animal Science, College of Agriculture and Natural Resources, University of Wyoming, Laramie, WY 82071, USA; College of Animal Science and Technology, Northwest A&F University, Yangling, Shaanxi 712100, China
| | - Wei Guo
- Animal Science, College of Agriculture and Natural Resources, University of Wyoming, Laramie, WY 82071, USA
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47
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Kralovicova J, Vorechovsky I. Alternative splicing of U2AF1 reveals a shared repression mechanism for duplicated exons. Nucleic Acids Res 2016; 45:417-434. [PMID: 27566151 PMCID: PMC5224494 DOI: 10.1093/nar/gkw733] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2016] [Revised: 08/10/2016] [Accepted: 08/11/2016] [Indexed: 12/30/2022] Open
Abstract
The auxiliary factor of U2 small nuclear ribonucleoprotein (U2AF) facilitates branch point (BP) recognition and formation of lariat introns. The gene for the 35-kD subunit of U2AF gives rise to two protein isoforms (termed U2AF35a and U2AF35b) that are encoded by alternatively spliced exons 3 and Ab, respectively. The splicing recognition sequences of exon 3 are less favorable than exon Ab, yet U2AF35a expression is higher than U2AF35b across tissues. We show that U2AF35b repression is facilitated by weak, closely spaced BPs next to a long polypyrimidine tract of exon Ab. Each BP lacked canonical uridines at position -2 relative to the BP adenines, with efficient U2 base-pairing interactions predicted only for shifted registers reminiscent of programmed ribosomal frameshifting. The BP cluster was compensated by interactions involving unpaired cytosines in an upstream, EvoFold-predicted stem loop (termed ESL) that binds FUBP1/2. Exon Ab inclusion correlated with predicted free energies of mutant ESLs, suggesting that the ESL operates as a conserved rheostat between long inverted repeats upstream of each exon. The isoform-specific U2AF35 expression was U2AF65-dependent, required interactions between the U2AF-homology motif (UHM) and the α6 helix of U2AF35, and was fine-tuned by exon Ab/3 variants. Finally, we identify tandem homologous exons regulated by U2AF and show that their preferential responses to U2AF65-related proteins and SRSF3 are associated with unpaired pre-mRNA segments upstream of U2AF-repressed 3′ss. These results provide new insights into tissue-specific subfunctionalization of duplicated exons in vertebrate evolution and expand the repertoire of exon repression mechanisms that control alternative splicing.
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Affiliation(s)
- Jana Kralovicova
- University of Southampton, Faculty of Medicine, Southampton SO16 6YD, UK
| | - Igor Vorechovsky
- University of Southampton, Faculty of Medicine, Southampton SO16 6YD, UK
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48
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Bondy-Chorney E, Crawford Parks TE, Ravel-Chapuis A, Jasmin BJ, Côté J. Staufen1s role as a splicing factor and a disease modifier in Myotonic Dystrophy Type I. Rare Dis 2016; 4:e1225644. [PMID: 27695661 PMCID: PMC5027583 DOI: 10.1080/21675511.2016.1225644] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2016] [Revised: 06/23/2016] [Accepted: 08/11/2016] [Indexed: 12/19/2022] Open
Abstract
In a recent issue of PLOS Genetics, we reported that the double-stranded RNA-binding protein, Staufen1, functions as a disease modifier in the neuromuscular disorder Myotonic Dystrophy Type I (DM1). In this work, we demonstrated that Staufen1 regulates the alternative splicing of exon 11 of the human Insulin Receptor, a highly studied missplicing event in DM1, through Alu elements located in an intronic region. Furthermore, we found that Staufen1 overexpression regulates numerous alternative splicing events, potentially resulting in both positive and negative effects in DM1. Here, we discuss our major findings and speculate on the details of the mechanisms by which Staufen1 could regulate alternative splicing, in both normal and DM1 conditions. Finally, we highlight the importance of disease modifiers, such as Staufen1, in the DM1 pathology in order to understand the complex disease phenotype and for future development of new therapeutic strategies.
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Affiliation(s)
- Emma Bondy-Chorney
- Department of Cellular and Molecular Medicine, University of Ottawa, Center for Neuromuscular Disease , Ottawa, Ontario, Canada
| | - Tara E Crawford Parks
- Department of Cellular and Molecular Medicine, University of Ottawa, Center for Neuromuscular Disease , Ottawa, Ontario, Canada
| | - Aymeric Ravel-Chapuis
- Department of Cellular and Molecular Medicine, University of Ottawa, Center for Neuromuscular Disease , Ottawa, Ontario, Canada
| | - Bernard J Jasmin
- Department of Cellular and Molecular Medicine, University of Ottawa, Center for Neuromuscular Disease , Ottawa, Ontario, Canada
| | - Jocelyn Côté
- Department of Cellular and Molecular Medicine, University of Ottawa, Center for Neuromuscular Disease , Ottawa, Ontario, Canada
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49
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Two Polypyrimidine Tracts in Intron 4 of the Major Immediate Early Gene Are Critical for Gene Expression Switching from IE1 to IE2 and for Replication of Human Cytomegalovirus. J Virol 2016; 90:7339-7349. [PMID: 27252533 DOI: 10.1128/jvi.00837-16] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2016] [Accepted: 05/25/2016] [Indexed: 02/07/2023] Open
Abstract
UNLABELLED The human cytomegalovirus (HCMV) major immediate early (MIE) gene is essential for viral replication. The most abundant products encoded by the MIE gene include IE1 and IE2. Genes of IE1 and IE2 share the MIE promoter (MIEP), the first 3 exons, and the first 2 introns. IE1 is expressed earlier than IE2 after CMV infection or MIE gene transfection. In this study, we identified 2 polypyrimidine (Py) tracts in intron 4 (between exons 4 and 5) that are responsible for transcriptional switching from IE1 to IE2. The first Py is important and the second one is essential for the splicing and expression of IE2. In searching for the mechanisms of MIE gene switching from IE1 to IE2, we found that the second Py was required for the IE2's fourth intron to bind to a splicing factor such as U2AF65, as determined by an RNA electrophoretic mobility shift assay and a chromatin immunoprecipitation (ChIP) assay, while the first Py enhanced the binding of U2AF65 with the intron. An HCMV BACmid with the second Py mutated failed to produce any virus, while the HCMV with the first Py mutated replicated with a defective phenotype. Furthermore, we designed a small RNA (scRNAPy) that is complementary to the intron RNA covering the two Pys. The scRNAPy interfered with the interaction of U2AF65 with the intron and repressed the IE2 expression. Therefore, our studies implied that IE2 gene splicing might be an anti-CMV target. IMPORTANCE CMV is a ubiquitous herpesvirus and a significant cause of disease and death in the immunocompromised and elderly. Insights into its gene regulation will provide clues in designing anti-CMV strategies. The MIE gene is one of the earliest genes of CMV and is essential for CMV replication. It is known that the MIE gene needs to be spliced to produce more than two proteins; however, how MIE gene splicing is regulated remains elusive. In the present studies, we identified two Pys in intron 4 and found that the first Py is important and the second is required for the splicing and expression of IE2. We further investigated the mechanisms of gene switching from IE1 to IE2 and found that the two Pys are responsible for U2AF65's binding with intron 4. Therefore, the Pys in intron 4 are the cis elements that determine the fate of IE2 splicing. Furthermore, we found that a small RNA that is complementary to intron 4 repressed IE2 expression. Hence, we provide the first piece of evidence for a unique mechanism of MIE gene regulation at the splicing level.
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Abstract
Pre-mRNA splicing is a key post-transcriptional regulation process in which introns are excised and exons are ligated together. A novel class of structured intron was recently discovered in fish. Simple expansions of complementary AC and GT dimers at opposite boundaries of an intron were found to form a bridging structure, thereby enforcing correct splice site pairing across the intron. In some fish introns, the RNA structures are strong enough to bypass the need of regulatory protein factors for splicing. Here, we discuss the prevalence and potential functions of highly structured introns. In humans, structured introns usually arise through the co-occurrence of C and G-rich repeats at intron boundaries. We explore the potentially instructive example of the HLA receptor genes. In HLA pre-mRNA, structured introns flank the exons that encode the highly polymorphic β sheet cleft, making the processing of the transcript robust to variants that disrupt splicing factor binding. While selective forces that have shaped HLA receptor are fairly atypical, numerous other highly polymorphic genes that encode receptors contain structured introns. Finally, we discuss how the elevated mutation rate associated with the simple repeats that often compose structured intron can make structured introns themselves rapidly evolving elements.
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Affiliation(s)
- Chien-Ling Lin
- a Molecular Biology, Cell Biology and Biochemistry, Brown University , Providence , RI , USA
| | - Allison J Taggart
- a Molecular Biology, Cell Biology and Biochemistry, Brown University , Providence , RI , USA
| | - William G Fairbrother
- a Molecular Biology, Cell Biology and Biochemistry, Brown University , Providence , RI , USA.,b Center for Computational Molecular Biology, Brown University , Providence , RI , USA.,c Hassenfeld Child Health Innovation Institute of Brown University , Providence , RI , USA
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