1
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Giudice J, Jiang H. Splicing regulation through biomolecular condensates and membraneless organelles. Nat Rev Mol Cell Biol 2024; 25:683-700. [PMID: 38773325 DOI: 10.1038/s41580-024-00739-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/22/2024] [Indexed: 05/23/2024]
Abstract
Biomolecular condensates, sometimes also known as membraneless organelles (MLOs), can form through weak multivalent intermolecular interactions of proteins and nucleic acids, a process often associated with liquid-liquid phase separation. Biomolecular condensates are emerging as sites and regulatory platforms of vital cellular functions, including transcription and RNA processing. In the first part of this Review, we comprehensively discuss how alternative splicing regulates the formation and properties of condensates, and conversely the roles of biomolecular condensates in splicing regulation. In the second part, we focus on the spatial connection between splicing regulation and nuclear MLOs such as transcriptional condensates, splicing condensates and nuclear speckles. We then discuss key studies showing how splicing regulation through biomolecular condensates is implicated in human pathologies such as neurodegenerative diseases, different types of cancer, developmental disorders and cardiomyopathies, and conclude with a discussion of outstanding questions pertaining to the roles of condensates and MLOs in splicing regulation and how to experimentally study them.
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Affiliation(s)
- Jimena Giudice
- Department of Cell Biology and Physiology, The University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
- McAllister Heart Institute, School of Medicine, The University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
| | - Hao Jiang
- Department of Biochemistry and Molecular Genetics, University of Virginia School of Medicine, Charlottesville, VA, USA.
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2
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Tang P, Yang J, Chen Z, Du C, Yang Y, Zhao H, Huang L, Li G, Liu F, Dong B, Shan T, Bao X, Zhou Y. Nuclear retention coupled with sequential polyadenylation dictates post-transcriptional m 6A modification in the nucleus. Mol Cell 2024:S1097-2765(24)00593-8. [PMID: 39127036 DOI: 10.1016/j.molcel.2024.07.017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2023] [Revised: 06/28/2024] [Accepted: 07/17/2024] [Indexed: 08/12/2024]
Abstract
N6-methyladenosine (m6A) modification is deemed to be co-transcriptionally installed on pre-mRNAs, thereby influencing various downstream RNA metabolism events. However, the causal relationship between m6A modification and RNA processing is often unclear, resulting in premature or even misleading generalizations on the function of m6A modification. Here, we develop 4sU-coupled m6A-level and isoform-characterization sequencing (4sU-m6A-LAIC-seq) and 4sU-GLORI to quantify the m6A levels for both newly synthesized and steady-state RNAs at transcript and single-base-resolution levels, respectively, which enable dissecting the relationship between m6A modification and alternative RNA polyadenylation. Unexpectedly, our results show that many m6A addition events occur post-transcriptionally, especially on transcripts with high m6A levels. Importantly, we find higher m6A levels on shorter 3' UTR isoforms, which likely result from sequential polyadenylation of longer 3' UTR isoforms with prolonged nuclear dwelling time. Therefore, m6A modification can also take place post-transcriptionally to intimately couple with other key RNA metabolism processes to establish and dynamically regulate epi-transcriptomics in mammalian cells.
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Affiliation(s)
- Peng Tang
- College of Life Sciences, TaiKang Center for Life and Medical Sciences, Hubei Key Laboratory of Cell Homeostasis, RNA Institute, Wuhan University, Wuhan, China; CAS Key Laboratory of Regenerative Biology, Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, China
| | - Jiayi Yang
- College of Life Sciences, TaiKang Center for Life and Medical Sciences, Hubei Key Laboratory of Cell Homeostasis, RNA Institute, Wuhan University, Wuhan, China
| | - Zonggui Chen
- Institute of Advanced Studies, Wuhan University, Wuhan, China
| | - Chen Du
- College of Life Sciences, TaiKang Center for Life and Medical Sciences, Hubei Key Laboratory of Cell Homeostasis, RNA Institute, Wuhan University, Wuhan, China; Frontier Science Center for Immunology and Metabolism, State Key Laboratory of Virology, Wuhan University, Wuhan, China
| | - Yang Yang
- College of Life Sciences, TaiKang Center for Life and Medical Sciences, Hubei Key Laboratory of Cell Homeostasis, RNA Institute, Wuhan University, Wuhan, China; Institute of Pediatric Research, Children's Hospital of Soochow University, Suzhou, China
| | - Haiping Zhao
- Institutes of Biomedical Sciences, Fudan University, Shanghai, China
| | - Li Huang
- College of Life Sciences, TaiKang Center for Life and Medical Sciences, Hubei Key Laboratory of Cell Homeostasis, RNA Institute, Wuhan University, Wuhan, China
| | - Guangnan Li
- College of Life Sciences, TaiKang Center for Life and Medical Sciences, Hubei Key Laboratory of Cell Homeostasis, RNA Institute, Wuhan University, Wuhan, China
| | - Feiyan Liu
- College of Life Sciences, TaiKang Center for Life and Medical Sciences, Hubei Key Laboratory of Cell Homeostasis, RNA Institute, Wuhan University, Wuhan, China
| | - Bei Dong
- CAS Key Laboratory of Regenerative Biology, Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, China
| | - Ting Shan
- College of Life Sciences, TaiKang Center for Life and Medical Sciences, Hubei Key Laboratory of Cell Homeostasis, RNA Institute, Wuhan University, Wuhan, China
| | - Xichen Bao
- CAS Key Laboratory of Regenerative Biology, Guangdong Provincial Key Laboratory of Stem Cell and Regenerative Medicine, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, China
| | - Yu Zhou
- College of Life Sciences, TaiKang Center for Life and Medical Sciences, Hubei Key Laboratory of Cell Homeostasis, RNA Institute, Wuhan University, Wuhan, China; Institute of Advanced Studies, Wuhan University, Wuhan, China; Frontier Science Center for Immunology and Metabolism, State Key Laboratory of Virology, Wuhan University, Wuhan, China.
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3
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Kuang S, Pollard KS. Exploring the roles of RNAs in chromatin architecture using deep learning. Nat Commun 2024; 15:6373. [PMID: 39075082 PMCID: PMC11286850 DOI: 10.1038/s41467-024-50573-w] [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: 10/23/2023] [Accepted: 07/12/2024] [Indexed: 07/31/2024] Open
Abstract
Recent studies have highlighted the impact of both transcription and transcripts on 3D genome organization, particularly its dynamics. Here, we propose a deep learning framework, called AkitaR, that leverages both genome sequences and genome-wide RNA-DNA interactions to investigate the roles of chromatin-associated RNAs (caRNAs) on genome folding in HFFc6 cells. In order to disentangle the cis- and trans-regulatory roles of caRNAs, we have compared models with nascent transcripts, trans-located caRNAs, open chromatin data, or DNA sequence alone. Both nascent transcripts and trans-located caRNAs improve the models' predictions, especially at cell-type-specific genomic regions. Analyses of feature importance scores reveal the contribution of caRNAs at TAD boundaries, chromatin loops and nuclear sub-structures such as nuclear speckles and nucleoli to the models' predictions. Furthermore, we identify non-coding RNAs (ncRNAs) known to regulate chromatin structures, such as MALAT1 and NEAT1, as well as several new RNAs, RNY5, RPPH1, POLG-DT and THBS1-IT1, that might modulate chromatin architecture through trans-interactions in HFFc6. Our modeling also suggests that transcripts from Alus and other repetitive elements may facilitate chromatin interactions through trans R-loop formation. Our findings provide insights and generate testable hypotheses about the roles of caRNAs in shaping chromatin organization.
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Affiliation(s)
- Shuzhen Kuang
- Gladstone Institute of Data Science and Biotechnology, San Francisco, CA, USA
| | - Katherine S Pollard
- Gladstone Institute of Data Science and Biotechnology, San Francisco, CA, USA.
- Department of Epidemiology & Biostatistics, University of California, San Francisco, CA, USA.
- Chan Zuckerberg Biohub, San Francisco, CA, USA.
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4
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Kashyap MK, Karathia H, Kumar D, Vera Alvarez R, Forero-Forero JV, Moreno E, Lujan JV, Amaya-Chanaga CI, Vidal NM, Yu Z, Ghia EM, Lengerke-Diaz PA, Achinko D, Choi MY, Rassenti LZ, Mariño-Ramírez L, Mount SM, Hannenhalli S, Kipps TJ, Castro JE. Aberrant spliceosome activity via elevated intron retention and upregulation and phosphorylation of SF3B1 in chronic lymphocytic leukemia. MOLECULAR THERAPY. NUCLEIC ACIDS 2024; 35:102202. [PMID: 38846999 PMCID: PMC11154714 DOI: 10.1016/j.omtn.2024.102202] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/14/2022] [Accepted: 04/24/2024] [Indexed: 06/09/2024]
Abstract
Splicing factor 3b subunit 1 (SF3B1) is the largest subunit and core component of the spliceosome. Inhibition of SF3B1 was associated with an increase in broad intron retention (IR) on most transcripts, suggesting that IR can be used as a marker of spliceosome inhibition in chronic lymphocytic leukemia (CLL) cells. Furthermore, we separately analyzed exonic and intronic mapped reads on annotated RNA-sequencing transcripts obtained from B cells (n = 98 CLL patients) and healthy volunteers (n = 9). We measured intron/exon ratio to use that as a surrogate for alternative RNA splicing (ARS) and found that 66% of CLL-B cell transcripts had significant IR elevation compared with normal B cells (NBCs) and that correlated with mRNA downregulation and low expression levels. Transcripts with the highest IR levels belonged to biological pathways associated with gene expression and RNA splicing. A >2-fold increase of active pSF3B1 was observed in CLL-B cells compared with NBCs. Additionally, when the CLL-B cells were treated with macrolides (pladienolide-B), a significant decrease in pSF3B1, but not total SF3B1 protein, was observed. These findings suggest that IR/ARS is increased in CLL, which is associated with SF3B1 phosphorylation and susceptibility to SF3B1 inhibitors. These data provide additional support to the relevance of ARS in carcinogenesis and evidence of pSF3B1 participation in this process.
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Affiliation(s)
- Manoj Kumar Kashyap
- Moores Cancer Center, University of California, San Diego, La Jolla, CA 92093-0820, USA
- Division of Hematology Oncology, Department of Medicine, University of California, San Diego, La Jolla, CA 92093, USA
- Amity Stem Cell Institute, Amity Medical School, Amity University Haryana, Panchgaon (Manesar), Gurugram (HR) 122413, India
| | - Hiren Karathia
- Advanced Biomedical Computational Science and National Center for Advancing Translational Sciences, National Cancer Institute, National Institutes of Health, Frederick, MD, USA
- Greenwood Genetic Center, Greenwood, SC, USA
- Center for Bioinformatics and Computational Biology, University of Maryland, College Park, MD 20742, USA
| | - Deepak Kumar
- Moores Cancer Center, University of California, San Diego, La Jolla, CA 92093-0820, USA
| | - Roberto Vera Alvarez
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD, USA
| | | | - Eider Moreno
- Department of Internal Medicine, Division of Hematology-Oncology, Mayo Clinic, Phoenix, AZ 85054, USA
| | - Juliana Velez Lujan
- Moores Cancer Center, University of California, San Diego, La Jolla, CA 92093-0820, USA
| | | | - Newton Medeiros Vidal
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD, USA
| | - Zhe Yu
- Moores Cancer Center, University of California, San Diego, La Jolla, CA 92093-0820, USA
| | - Emanuela M. Ghia
- Moores Cancer Center, University of California, San Diego, La Jolla, CA 92093-0820, USA
- Division of Hematology Oncology, Department of Medicine, University of California, San Diego, La Jolla, CA 92093, USA
- Center for Novel Therapeutics, University of California, San Diego, La Jolla, CA 92037, USA
| | - Paula A. Lengerke-Diaz
- Department of Internal Medicine, Division of Hematology-Oncology, Mayo Clinic, Phoenix, AZ 85054, USA
| | - Daniel Achinko
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD, USA
| | - Michael Y. Choi
- Moores Cancer Center, University of California, San Diego, La Jolla, CA 92093-0820, USA
- Division of Hematology Oncology, Department of Medicine, University of California, San Diego, La Jolla, CA 92093, USA
- Center for Novel Therapeutics, University of California, San Diego, La Jolla, CA 92037, USA
| | - Laura Z. Rassenti
- Moores Cancer Center, University of California, San Diego, La Jolla, CA 92093-0820, USA
- Division of Hematology Oncology, Department of Medicine, University of California, San Diego, La Jolla, CA 92093, USA
- Center for Novel Therapeutics, University of California, San Diego, La Jolla, CA 92037, USA
| | - Leonardo Mariño-Ramírez
- National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Bethesda, MD, USA
| | - Stephen M. Mount
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, Maryland 20742, USA
| | - Sridhar Hannenhalli
- Cancer Data Science Lab, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA
| | - Thomas J. Kipps
- Moores Cancer Center, University of California, San Diego, La Jolla, CA 92093-0820, USA
- Division of Hematology Oncology, Department of Medicine, University of California, San Diego, La Jolla, CA 92093, USA
- Center for Novel Therapeutics, University of California, San Diego, La Jolla, CA 92037, USA
| | - Januario E. Castro
- Moores Cancer Center, University of California, San Diego, La Jolla, CA 92093-0820, USA
- Department of Internal Medicine, Division of Hematology-Oncology, Mayo Clinic, Phoenix, AZ 85054, USA
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5
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Gimeno-Valiente F, López-Rodas G, Castillo J, Franco L. The Many Roads from Alternative Splicing to Cancer: Molecular Mechanisms Involving Driver Genes. Cancers (Basel) 2024; 16:2123. [PMID: 38893242 PMCID: PMC11171328 DOI: 10.3390/cancers16112123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2024] [Revised: 05/29/2024] [Accepted: 05/31/2024] [Indexed: 06/21/2024] Open
Abstract
Cancer driver genes are either oncogenes or tumour suppressor genes that are classically activated or inactivated, respectively, by driver mutations. Alternative splicing-which produces various mature mRNAs and, eventually, protein variants from a single gene-may also result in driving neoplastic transformation because of the different and often opposed functions of the variants of driver genes. The present review analyses the different alternative splicing events that result in driving neoplastic transformation, with an emphasis on their molecular mechanisms. To do this, we collected a list of 568 gene drivers of cancer and revised the literature to select those involved in the alternative splicing of other genes as well as those in which its pre-mRNA is subject to alternative splicing, with the result, in both cases, of producing an oncogenic isoform. Thirty-one genes fall into the first category, which includes splicing factors and components of the spliceosome and splicing regulators. In the second category, namely that comprising driver genes in which alternative splicing produces the oncogenic isoform, 168 genes were found. Then, we grouped them according to the molecular mechanisms responsible for alternative splicing yielding oncogenic isoforms, namely, mutations in cis splicing-determining elements, other causes involving non-mutated cis elements, changes in splicing factors, and epigenetic and chromatin-related changes. The data given in the present review substantiate the idea that aberrant splicing may regulate the activation of proto-oncogenes or inactivation of tumour suppressor genes and details on the mechanisms involved are given for more than 40 driver genes.
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Affiliation(s)
- Francisco Gimeno-Valiente
- Cancer Evolution and Genome Instability Laboratory, University College London Cancer Institute, London WC1E 6DD, UK;
| | - Gerardo López-Rodas
- Department of Oncology, Institute of Health Research INCLIVA, 46010 Valencia, Spain; (G.L.-R.); (J.C.)
- Department of Biochemistry and Molecular Biology, Universitat de València, 46010 Valencia, Spain
| | - Josefa Castillo
- Department of Oncology, Institute of Health Research INCLIVA, 46010 Valencia, Spain; (G.L.-R.); (J.C.)
- Department of Biochemistry and Molecular Biology, Universitat de València, 46010 Valencia, Spain
- Centro de Investigación Biomédica en Red en Cáncer (CIBERONC), 28029 Madrid, Spain
| | - Luis Franco
- Department of Oncology, Institute of Health Research INCLIVA, 46010 Valencia, Spain; (G.L.-R.); (J.C.)
- Department of Biochemistry and Molecular Biology, Universitat de València, 46010 Valencia, Spain
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6
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Atkinson R, Georgiou M, Yang C, Szymanska K, Lahat A, Vasconcelos EJR, Ji Y, Moya Molina M, Collin J, Queen R, Dorgau B, Watson A, Kurzawa-Akanbi M, Laws R, Saxena A, Shyan Beh C, Siachisumo C, Goertler F, Karwatka M, Davey T, Inglehearn CF, McKibbin M, Lührmann R, Steel DH, Elliott DJ, Armstrong L, Urlaub H, Ali RR, Grellscheid SN, Johnson CA, Mozaffari-Jovin S, Lako M. PRPF8-mediated dysregulation of hBrr2 helicase disrupts human spliceosome kinetics and 5´-splice-site selection causing tissue-specific defects. Nat Commun 2024; 15:3138. [PMID: 38605034 PMCID: PMC11009313 DOI: 10.1038/s41467-024-47253-0] [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: 09/21/2023] [Accepted: 03/19/2024] [Indexed: 04/13/2024] Open
Abstract
The carboxy-terminus of the spliceosomal protein PRPF8, which regulates the RNA helicase Brr2, is a hotspot for mutations causing retinitis pigmentosa-type 13, with unclear role in human splicing and tissue-specificity mechanism. We used patient induced pluripotent stem cells-derived cells, carrying the heterozygous PRPF8 c.6926 A > C (p.H2309P) mutation to demonstrate retinal-specific endophenotypes comprising photoreceptor loss, apical-basal polarity and ciliary defects. Comprehensive molecular, transcriptomic, and proteomic analyses revealed a role of the PRPF8/Brr2 regulation in 5'-splice site (5'SS) selection by spliceosomes, for which disruption impaired alternative splicing and weak/suboptimal 5'SS selection, and enhanced cryptic splicing, predominantly in ciliary and retinal-specific transcripts. Altered splicing efficiency, nuclear speckles organisation, and PRPF8 interaction with U6 snRNA, caused accumulation of active spliceosomes and poly(A)+ mRNAs in unique splicing clusters located at the nuclear periphery of photoreceptors. Collectively these elucidate the role of PRPF8/Brr2 regulatory mechanisms in splicing and the molecular basis of retinal disease, informing therapeutic approaches.
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Affiliation(s)
| | - Maria Georgiou
- Biosciences Institute, Newcastle University, Newcastle, UK
| | - Chunbo Yang
- Biosciences Institute, Newcastle University, Newcastle, UK
| | | | - Albert Lahat
- Department of Biosciences, Durham University, Durham, UK
| | | | - Yanlong Ji
- Max-Planck-Institute for Multidisciplinary Sciences, Göttingen, Germany
- Institute of Clinical Chemistry, University Medical Center Göttingen, Göttingen, Germany
| | - Marina Moya Molina
- Biosciences Institute, Newcastle University, Newcastle, UK
- Newcells Biotech, Newcastle, UK
| | - Joseph Collin
- Biosciences Institute, Newcastle University, Newcastle, UK
| | - Rachel Queen
- Biosciences Institute, Newcastle University, Newcastle, UK
| | - Birthe Dorgau
- Biosciences Institute, Newcastle University, Newcastle, UK
| | - Avril Watson
- Biosciences Institute, Newcastle University, Newcastle, UK
- Newcells Biotech, Newcastle, UK
| | | | - Ross Laws
- Electron Microscopy Research Services, Newcastle University, Newcastle, UK
| | - Abhijit Saxena
- Biosciences Institute, Newcastle University, Newcastle, UK
| | - Chia Shyan Beh
- Biosciences Institute, Newcastle University, Newcastle, UK
| | | | | | | | - Tracey Davey
- Electron Microscopy Research Services, Newcastle University, Newcastle, UK
| | | | - Martin McKibbin
- Leeds Institute of Medical Research, University of Leeds, Leeds, UK
| | - Reinhard Lührmann
- Max-Planck-Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - David H Steel
- Biosciences Institute, Newcastle University, Newcastle, UK
| | | | - Lyle Armstrong
- Biosciences Institute, Newcastle University, Newcastle, UK
| | - Henning Urlaub
- Max-Planck-Institute for Multidisciplinary Sciences, Göttingen, Germany
- Institute of Clinical Chemistry, University Medical Center Göttingen, Göttingen, Germany
- Göttingen Center for Molecular Biosciences, Georg August University of Göttingen, Göttingen, Germany
| | - Robin R Ali
- Centre for Cell and Gene Therapy, Kings College London, London, UK
| | - Sushma-Nagaraja Grellscheid
- Department of Biosciences, Durham University, Durham, UK
- Department of Informatics, University of Bergen, Bergen, Norway
| | - Colin A Johnson
- Leeds Institute of Medical Research, University of Leeds, Leeds, UK.
| | - Sina Mozaffari-Jovin
- Max-Planck-Institute for Multidisciplinary Sciences, Göttingen, Germany.
- Department of Medical Genetics and Medical Genetics Research Center, School of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran.
| | - Majlinda Lako
- Biosciences Institute, Newcastle University, Newcastle, UK.
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7
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Coté A, O'Farrell A, Dardani I, Dunagin M, Coté C, Wan Y, Bayatpour S, Drexler HL, Alexander KA, Chen F, Wassie AT, Patel R, Pham K, Boyden ES, Berger S, Phillips-Cremins J, Churchman LS, Raj A. Post-transcriptional splicing can occur in a slow-moving zone around the gene. eLife 2024; 12:RP91357. [PMID: 38577979 PMCID: PMC10997330 DOI: 10.7554/elife.91357] [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] [Indexed: 04/06/2024] Open
Abstract
Splicing is the stepwise molecular process by which introns are removed from pre-mRNA and exons are joined together to form mature mRNA sequences. The ordering and spatial distribution of these steps remain controversial, with opposing models suggesting splicing occurs either during or after transcription. We used single-molecule RNA FISH, expansion microscopy, and live-cell imaging to reveal the spatiotemporal distribution of nascent transcripts in mammalian cells. At super-resolution levels, we found that pre-mRNA formed clouds around the transcription site. These clouds indicate the existence of a transcription-site-proximal zone through which RNA move more slowly than in the nucleoplasm. Full-length pre-mRNA undergo continuous splicing as they move through this zone following transcription, suggesting a model in which splicing can occur post-transcriptionally but still within the proximity of the transcription site, thus seeming co-transcriptional by most assays. These results may unify conflicting reports of co-transcriptional versus post-transcriptional splicing.
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Affiliation(s)
- Allison Coté
- Department of Bioengineering, University of PennsylvaniaPhiladelphiaUnited States
| | - Aoife O'Farrell
- Department of Bioengineering, University of PennsylvaniaPhiladelphiaUnited States
| | - Ian Dardani
- Department of Bioengineering, University of PennsylvaniaPhiladelphiaUnited States
| | - Margaret Dunagin
- Department of Bioengineering, University of PennsylvaniaPhiladelphiaUnited States
| | - Chris Coté
- Department of Bioengineering, University of PennsylvaniaPhiladelphiaUnited States
| | - Yihan Wan
- School of Life Sciences, Westlake UniversityHangzhouChina
| | - Sareh Bayatpour
- Department of Bioengineering, University of PennsylvaniaPhiladelphiaUnited States
| | - Heather L Drexler
- Department of Genetics, Blavatnik Institute, Harvard Medical SchoolBostonUnited States
| | - Katherine A Alexander
- Department of Cell and Developmental Biology, Penn Institute of Epigenetics, Perelman School of Medicine, University of PennsylvaniaPhiladelphiaUnited States
| | - Fei Chen
- Broad Institute of MIT and HarvardCambridgeUnited States
| | - Asmamaw T Wassie
- Department of Cell and Molecular Biology, University of PennsylvaniaPhiladelphiaUnited States
| | - Rohan Patel
- Department of Bioengineering, University of PennsylvaniaPhiladelphiaUnited States
| | - Kenneth Pham
- Department of Cell and Molecular Biology, University of PennsylvaniaPhiladelphiaUnited States
| | - Edward S Boyden
- Departments of Biological Engineering and Brain and Cognitive Sciences, Media Lab and McGovern Institute, Massachusetts Institute of TechnologyCambridgeUnited States
| | - Shelly Berger
- Department of Cell and Developmental Biology, Penn Institute of Epigenetics, Perelman School of Medicine, University of PennsylvaniaPhiladelphiaUnited States
| | | | - L Stirling Churchman
- Department of Genetics, Blavatnik Institute, Harvard Medical SchoolBostonUnited States
| | - Arjun Raj
- Department of Bioengineering, University of PennsylvaniaPhiladelphiaUnited States
- Department of Genetics, Perelman School of Medicine, University of PennsylvaniaPhiladelphiaUnited States
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8
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Park J, Kim JJ, Ryu JK. Mechanism of phase condensation for chromosome architecture and function. Exp Mol Med 2024; 56:809-819. [PMID: 38658703 PMCID: PMC11059216 DOI: 10.1038/s12276-024-01226-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2023] [Revised: 02/23/2024] [Accepted: 02/28/2024] [Indexed: 04/26/2024] Open
Abstract
Chromosomal phase separation is involved in a broad spectrum of chromosome organization and functional processes. Nonetheless, the intricacy of this process has left its molecular mechanism unclear. Here, we introduce the principles governing phase separation and its connections to physiological roles in this context. Our primary focus is contrasting two phase separation mechanisms: self-association-induced phase separation (SIPS) and bridging-induced phase separation (BIPS). We provide a comprehensive discussion of the distinct features characterizing these mechanisms and offer illustrative examples that suggest their broad applicability. With a detailed understanding of these mechanisms, we explore their associations with nucleosomes and chromosomal biological functions. This comprehensive review contributes to the exploration of uncharted territory in the intricate interplay between chromosome architecture and function.
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Affiliation(s)
- Jeongveen Park
- Department of Physics and Astronomy, Seoul National University, Seoul, 08826, South Korea
| | - Jeong-Jun Kim
- Department of Physics and Astronomy, Seoul National University, Seoul, 08826, South Korea
| | - Je-Kyung Ryu
- Department of Physics and Astronomy, Seoul National University, Seoul, 08826, South Korea.
- Institute of Applied Physics of Seoul National University, Seoul, 08826, South Korea.
- Institute of Molecular Biology and Genetics, Seoul National University, Seoul, 08826, South Korea.
- Department of Biological Sciences, Seoul National University, Seoul, 08826, South Korea.
- Interdisciplinary Program in Neuroscience, Seoul National University, Seoul, 08826, South Korea.
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9
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Dillingham CM, Cormaty H, Morgan EC, Tak AI, Esgdaille DE, Boutz PL, Sridharan R. KDM3A and KDM3B Maintain Naïve Pluripotency Through the Regulation of Alternative Splicing. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.05.31.543088. [PMID: 37398291 PMCID: PMC10312572 DOI: 10.1101/2023.05.31.543088] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/04/2023]
Abstract
Histone modifying enzymes play a central role in maintaining cell identity by establishing a conducive chromatin environment for lineage specific transcription factor activity. Pluripotent embryonic stem cell (ESC) identity is characterized by a lower abundance of gene repression associated histone modifications that enables rapid response to differentiation cues. The KDM3 family of histone demethylases removes the repressive histone H3 lysine 9 dimethylation (H3K9me2). Here we uncover a surprising role for the KDM3 proteins in the maintenance of the pluripotent state through post-transcriptional regulation. We find that KDM3A and KDM3B interact with RNA processing factors such as EFTUD2 and PRMT5. Acute selective degradation of the endogenous KDM3A and KDM3B proteins resulted in altered splicing independent of H3K9me2 status or catalytic activity. These splicing changes partially resemble the splicing pattern of the more blastocyst-like ground state of pluripotency and occurred in important chromatin and transcription factors such as Dnmt3b, Tbx3 and Tcf12. Our findings reveal non-canonical roles of histone demethylating enzymes in splicing to regulate cell identity.
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Affiliation(s)
- Caleb M Dillingham
- Wisconsin Institute for Discovery, University of Wisconsin-Madison, Madison, WI, 53715, USA
- Department of Cell and Regenerative Biology, University of Wisconsin-Madison, Madison, WI, 53792, USA
- Pathology and Laboratory Medicine, University of Wisconsin-Madison, Madison, WI, 53705, USA
| | - Harshini Cormaty
- Wisconsin Institute for Discovery, University of Wisconsin-Madison, Madison, WI, 53715, USA
- Department of Cell and Regenerative Biology, University of Wisconsin-Madison, Madison, WI, 53792, USA
- Laboratory of Genetics, University of Wisconsin-Madison, Madison, WI, 53706, USA
| | - Ellen C Morgan
- Wisconsin Institute for Discovery, University of Wisconsin-Madison, Madison, WI, 53715, USA
- Department of Cell and Regenerative Biology, University of Wisconsin-Madison, Madison, WI, 53792, USA
| | - Andrew I Tak
- Wisconsin Institute for Discovery, University of Wisconsin-Madison, Madison, WI, 53715, USA
- Department of Cell and Regenerative Biology, University of Wisconsin-Madison, Madison, WI, 53792, USA
- Molecular and Cellular Pharmacology Training Program, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Dakarai E Esgdaille
- Department of Biochemistry and Biophysics, Center for RNA Biology, Wilmot Cancer Center, University of Rochester School of Medicine and Dentistry
| | - Paul L Boutz
- Department of Biomedical Genetics, University of Rochester School of Medicine and Dentistry
| | - Rupa Sridharan
- Wisconsin Institute for Discovery, University of Wisconsin-Madison, Madison, WI, 53715, USA
- Department of Cell and Regenerative Biology, University of Wisconsin-Madison, Madison, WI, 53792, USA
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10
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Borden KLB. The eukaryotic translation initiation factor eIF4E unexpectedly acts in splicing thereby coupling mRNA processing with translation: eIF4E induces widescale splicing reprogramming providing system-wide connectivity between splicing, nuclear mRNA export and translation. Bioessays 2024; 46:e2300145. [PMID: 37926700 PMCID: PMC11021180 DOI: 10.1002/bies.202300145] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2023] [Revised: 10/17/2023] [Accepted: 10/24/2023] [Indexed: 11/07/2023]
Abstract
Recent findings position the eukaryotic translation initiation factor eIF4E as a novel modulator of mRNA splicing, a process that impacts the form and function of resultant proteins. eIF4E physically interacts with the spliceosome and with some intron-containing transcripts implying a direct role in some splicing events. Moreover, eIF4E drives the production of key components of the splicing machinery underpinning larger scale impacts on splicing. These drive eIF4E-dependent reprogramming of the splicing signature. This work completes a series of studies demonstrating eIF4E acts in all the major mRNA maturation steps whereby eIF4E drives production of the RNA processing machinery and escorts some transcripts through various maturation steps. In this way, eIF4E couples the mRNA processing-export-translation axis linking nuclear mRNA processing to cytoplasmic translation. eIF4E elevation is linked to worse outcomes in acute myeloid leukemia patients where these activities are dysregulated. Understanding these effects provides new insight into post-transcriptional control and eIF4E-driven cancers.
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Affiliation(s)
- Katherine L. B. Borden
- Institute for Research in Immunology and Cancer and Department of Pathology and Cell BiologyUniversity of MontrealMontrealQuebecCanada
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11
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Fukumura K, Sperotto L, Seuß S, Kang HS, Yoshimoto R, Sattler M, Mayeda A. SAP30BP interacts with RBM17/SPF45 to promote splicing in a subset of human short introns. Cell Rep 2023; 42:113534. [PMID: 38065098 DOI: 10.1016/j.celrep.2023.113534] [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: 03/13/2023] [Revised: 11/03/2023] [Accepted: 11/16/2023] [Indexed: 12/30/2023] Open
Abstract
Human pre-mRNA splicing requires the removal of introns with highly variable lengths, from tens to over a million nucleotides. Therefore, mechanisms of intron recognition and splicing are likely not universal. Recently, we reported that splicing in a subset of human short introns with truncated polypyrimidine tracts depends on RBM17 (SPF45), instead of the canonical splicing factor U2 auxiliary factor (U2AF) heterodimer. Here, we demonstrate that SAP30BP, a factor previously implicated in transcriptional control, is an essential splicing cofactor for RBM17. In vitro binding and nuclear magnetic resonance analyses demonstrate that a U2AF-homology motif (UHM) in RBM17 binds directly to a newly identified UHM-ligand motif in SAP30BP. We show that this RBM17-SAP30BP interaction is required to specifically recruit RBM17 to phosphorylated SF3B1 (SF3b155), a U2 small nuclear ribonucleoprotein (U2 snRNP) component in active spliceosomes. We propose a mechanism for splicing in a subset of short introns, in which SAP30BP guides RBM17 in the assembly of active spliceosomes.
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Affiliation(s)
- Kazuhiro Fukumura
- Division of Gene Expression Mechanism, Center for Medical Science, Fujita Health University, Toyoake, Aichi 470-1192, Japan.
| | - Luca Sperotto
- Institute of Structural Biology, Helmholtz Zentrum München, 85764 Neuherberg, Germany; Bavarian NMR Center, TUM School of Natural Sciences, 85748 Garching, Germany
| | - Stefanie Seuß
- Institute of Structural Biology, Helmholtz Zentrum München, 85764 Neuherberg, Germany; Bavarian NMR Center, TUM School of Natural Sciences, 85748 Garching, Germany
| | - Hyun-Seo Kang
- Institute of Structural Biology, Helmholtz Zentrum München, 85764 Neuherberg, Germany; Bavarian NMR Center, TUM School of Natural Sciences, 85748 Garching, Germany
| | - Rei Yoshimoto
- Department of Applied Biological Sciences, Faculty of Agriculture, Setsunan University, Hirakata, Osaka 673-0101, Japan
| | - Michael Sattler
- Institute of Structural Biology, Helmholtz Zentrum München, 85764 Neuherberg, Germany; Bavarian NMR Center, TUM School of Natural Sciences, 85748 Garching, Germany
| | - Akila Mayeda
- Division of Gene Expression Mechanism, Center for Medical Science, Fujita Health University, Toyoake, Aichi 470-1192, Japan.
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12
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Sung HM, Schott J, Boss P, Lehmann JA, Hardt MR, Lindner D, Messens J, Bogeski I, Ohler U, Stoecklin G. Stress-induced nuclear speckle reorganization is linked to activation of immediate early gene splicing. J Cell Biol 2023; 222:e202111151. [PMID: 37956386 PMCID: PMC10641589 DOI: 10.1083/jcb.202111151] [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: 11/30/2021] [Revised: 07/13/2023] [Accepted: 09/29/2023] [Indexed: 11/15/2023] Open
Abstract
Current models posit that nuclear speckles (NSs) serve as reservoirs of splicing factors and facilitate posttranscriptional mRNA processing. Here, we discovered that ribotoxic stress induces a profound reorganization of NSs with enhanced recruitment of factors required for splice-site recognition, including the RNA-binding protein TIAR, U1 snRNP proteins and U2-associated factor 65, as well as serine 2 phosphorylated RNA polymerase II. NS reorganization relies on the stress-activated p38 mitogen-activated protein kinase (MAPK) pathway and coincides with splicing activation of both pre-existing and newly synthesized pre-mRNAs. In particular, ribotoxic stress causes targeted excision of retained introns from pre-mRNAs of immediate early genes (IEGs), whose transcription is induced during the stress response. Importantly, enhanced splicing of the IEGs ZFP36 and FOS is accompanied by relocalization of the corresponding nuclear mRNA foci to NSs. Our study reveals NSs as a dynamic compartment that is remodeled under stress conditions, whereby NSs appear to become sites of IEG transcription and efficient cotranscriptional splicing.
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Affiliation(s)
- Hsu-Min Sung
- Mannheim Institute for Innate Immunoscience (MI3) and Mannheim Cancer Center (MCC), Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
- Center for Molecular Biology of Heidelberg University (ZMBH), German Cancer Research Center (DKFZ)-ZMBH Alliance, Heidelberg, Germany
- VIB-VUB Center for Structural Biology, VIB, Brussels, Belgium
- Brussels Center for Redox Biology, Brussels, Belgium
- Structural Biology Brussels, Vrije Universiteit Brussel, Brussels, Belgium
- Molecular Physiology, Institute of Cardiovascular Physiology, University Medical Center, Georg-August-University, Göttingen, Germany
| | - Johanna Schott
- Mannheim Institute for Innate Immunoscience (MI3) and Mannheim Cancer Center (MCC), Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
- Center for Molecular Biology of Heidelberg University (ZMBH), German Cancer Research Center (DKFZ)-ZMBH Alliance, Heidelberg, Germany
| | - Philipp Boss
- Berlin Institute for Medical Systems Biology, Max-Delbrück-Center for Molecular Medicine, Berlin, Germany
- Department of Biology, Humboldt University, Berlin, Germany
| | - Janina A. Lehmann
- Mannheim Institute for Innate Immunoscience (MI3) and Mannheim Cancer Center (MCC), Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
- Center for Molecular Biology of Heidelberg University (ZMBH), German Cancer Research Center (DKFZ)-ZMBH Alliance, Heidelberg, Germany
| | - Marius Roland Hardt
- Mannheim Institute for Innate Immunoscience (MI3) and Mannheim Cancer Center (MCC), Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
- Center for Molecular Biology of Heidelberg University (ZMBH), German Cancer Research Center (DKFZ)-ZMBH Alliance, Heidelberg, Germany
| | - Doris Lindner
- Mannheim Institute for Innate Immunoscience (MI3) and Mannheim Cancer Center (MCC), Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
- Center for Molecular Biology of Heidelberg University (ZMBH), German Cancer Research Center (DKFZ)-ZMBH Alliance, Heidelberg, Germany
| | - Joris Messens
- VIB-VUB Center for Structural Biology, VIB, Brussels, Belgium
- Brussels Center for Redox Biology, Brussels, Belgium
- Structural Biology Brussels, Vrije Universiteit Brussel, Brussels, Belgium
| | - Ivan Bogeski
- Molecular Physiology, Institute of Cardiovascular Physiology, University Medical Center, Georg-August-University, Göttingen, Germany
| | - Uwe Ohler
- Berlin Institute for Medical Systems Biology, Max-Delbrück-Center for Molecular Medicine, Berlin, Germany
- Department of Biology, Humboldt University, Berlin, Germany
| | - Georg Stoecklin
- Mannheim Institute for Innate Immunoscience (MI3) and Mannheim Cancer Center (MCC), Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
- Center for Molecular Biology of Heidelberg University (ZMBH), German Cancer Research Center (DKFZ)-ZMBH Alliance, Heidelberg, Germany
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13
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Podszywalow-Bartnicka P, Neugebauer KM. Splicing under stress: A matter of time and place. J Cell Biol 2023; 222:e202311014. [PMID: 37988026 PMCID: PMC10660129 DOI: 10.1083/jcb.202311014] [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] [Indexed: 11/22/2023] Open
Abstract
Excision of introns during splicing regulates gene expression. In this issue, work by Sung et al. (https://doi.org/10.1083/jcb.202111151) demonstrates that the timing of intron removal in response to stress is coordinated in nuclear speckles, adding a component of spatial regulation to co-/post-transcriptional splicing.
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Affiliation(s)
| | - Karla M. Neugebauer
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven CT, USA
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14
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Dery KJ, Wong Z, Wei M, Kupiec-Weglinski JW. Mechanistic Insights into Alternative Gene Splicing in Oxidative Stress and Tissue Injury. Antioxid Redox Signal 2023. [PMID: 37776178 DOI: 10.1089/ars.2023.0437] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/01/2023]
Abstract
Significance: Oxidative stress (OS) and inflammation are inducers of tissue injury. Alternative splicing (AS) is an essential regulatory step for diversifying the eukaryotic proteome. Human diseases link AS to OS; however, the underlying mechanisms must be better understood. Recent Advances: Genome‑wide profiling studies identify new differentially expressed genes induced by OS-dependent ischemia/reperfusion injury. Overexpression of RNA-binding protein RBFOX1 protects against inflammation. Hypoxia-inducible factor-1α directs polypyrimidine tract binding protein 1 to regulate mouse carcinoembryonic antigen-related cell adhesion molecule 1 (Ceacam1) AS under OS conditions. Heterogeneous nuclear ribonucleoprotein L variant 1 contains an RGG/RG motif that coordinates with transcription factors to influence human CEACAM1 AS. Hypoxia intervention involving short interfering RNAs directed to long-noncoding RNA 260 polarizes M2 macrophages toward an anti-inflammatory phenotype and alleviates OS by inhibiting IL-28RA gene AS. Critical Issues: Protective mechanisms that eliminate reactive oxygen species (ROS) are important for resolving imbalances that lead to chronic inflammation. Defects in AS can cause ROS generation, cell death regulation, and the activation of innate and adaptive immune factors. We propose that AS pathways link redox regulation to the activation or suppression of the inflammatory response during cellular stress. Future Directions: Emergent studies using molecule-mediated RNA splicing are being conducted to exploit the immunogenicity of AS protein products. Deciphering the mechanisms that connect misspliced OS and pathologies should remain a priority. Controlled release of RNA directly into cells with clinical applications is needed as the demand for innovative nucleic acid delivery systems continues to be demonstrated.
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Affiliation(s)
- Kenneth J Dery
- The Dumont-UCLA Transplantation Center, Division of Liver and Pancreas Transplantation, Department of Surgery, David Geffen School of Medicine at UCLA, Los Angeles, California, USA
| | - Zeriel Wong
- The Dumont-UCLA Transplantation Center, Division of Liver and Pancreas Transplantation, Department of Surgery, David Geffen School of Medicine at UCLA, Los Angeles, California, USA
| | - Megan Wei
- The Dumont-UCLA Transplantation Center, Division of Liver and Pancreas Transplantation, Department of Surgery, David Geffen School of Medicine at UCLA, Los Angeles, California, USA
| | - Jerzy W Kupiec-Weglinski
- The Dumont-UCLA Transplantation Center, Division of Liver and Pancreas Transplantation, Department of Surgery, David Geffen School of Medicine at UCLA, Los Angeles, California, USA
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15
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Kuang S, Pollard KS. Exploring the Roles of RNAs in Chromatin Architecture Using Deep Learning. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.10.22.563498. [PMID: 37961712 PMCID: PMC10634726 DOI: 10.1101/2023.10.22.563498] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2023]
Abstract
Recent studies have highlighted the impact of both transcription and transcripts on 3D genome organization, particularly its dynamics. Here, we propose a deep learning framework, called AkitaR, that leverages both genome sequences and genome-wide RNA-DNA interactions to investigate the roles of chromatin-associated RNAs (caRNAs) on genome folding in HFFc6 cells. In order to disentangle the cis- and trans-regulatory roles of caRNAs, we compared models with nascent transcripts, trans-located caRNAs, open chromatin data, or DNA sequence alone. Both nascent transcripts and trans-located caRNAs improved the models' predictions, especially at cell-type-specific genomic regions. Analyses of feature importance scores revealed the contribution of caRNAs at TAD boundaries, chromatin loops and nuclear sub-structures such as nuclear speckles and nucleoli to the models' predictions. Furthermore, we identified non-coding RNAs (ncRNAs) known to regulate chromatin structures, such as MALAT1 and NEAT1, as well as several novel RNAs, RNY5, RPPH1, POLG-DT and THBS1-IT, that might modulate chromatin architecture through trans-interactions in HFFc6. Our modeling also suggests that transcripts from Alus and other repetitive elements may facilitate chromatin interactions through trans R-loop formation. Our findings provide new insights and generate testable hypotheses about the roles of caRNAs in shaping chromatin organization.
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Affiliation(s)
- Shuzhen Kuang
- Gladstone Institute of Data Science and Biotechnology, San Francisco, CA
| | - Katherine S. Pollard
- Gladstone Institute of Data Science and Biotechnology, San Francisco, CA
- Department of Epidemiology & Biostatistics, University of California, San Francisco, CA
- Chan Zuckerberg Biohub, San Francisco, CA, USA
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16
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Huang L, Li G, Du C, Jia Y, Yang J, Fan W, Xu Y, Cheng H, Zhou Y. The polyA tail facilitates splicing of last introns with weak 3' splice sites via PABPN1. EMBO Rep 2023; 24:e57128. [PMID: 37661812 PMCID: PMC10561182 DOI: 10.15252/embr.202357128] [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: 03/06/2023] [Revised: 08/04/2023] [Accepted: 08/16/2023] [Indexed: 09/05/2023] Open
Abstract
The polyA tail of mRNAs is important for many aspects of RNA metabolism. However, whether and how it regulates pre-mRNA splicing is still unknown. Here, we report that the polyA tail acts as a splicing enhancer for the last intron via the nuclear polyA binding protein PABPN1 in HeLa cells. PABPN1-depletion induces the retention of a group of introns with a weaker 3' splice site, and they show a strong 3'-end bias and mainly locate in nuclear speckles. The polyA tail is essential for PABPN1-enhanced last intron splicing and functions in a length-dependent manner. Tethering PABPN1 to nonpolyadenylated transcripts also promotes splicing, suggesting a direct role for PABPN1 in splicing regulation. Using TurboID-MS, we construct the PABPN1 interactome, including many spliceosomal and RNA-binding proteins. Specifically, PABPN1 can recruit RBM26&27 to promote splicing by interacting with the coiled-coil and RRM domain of RBM27. PABPN1-regulated terminal intron splicing is conserved in mice. Together, our study establishes a novel mode of post-transcriptional splicing regulation via the polyA tail and PABPN1.
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Affiliation(s)
- Li Huang
- College of Life Sciences, TaiKang Center for Life and Medical Sciences, RNA InstituteWuhan UniversityWuhanChina
| | - Guangnan Li
- College of Life Sciences, TaiKang Center for Life and Medical Sciences, RNA InstituteWuhan UniversityWuhanChina
| | - Chen Du
- College of Life Sciences, TaiKang Center for Life and Medical Sciences, RNA InstituteWuhan UniversityWuhanChina
| | - Yu Jia
- College of Life Sciences, TaiKang Center for Life and Medical Sciences, RNA InstituteWuhan UniversityWuhanChina
| | - Jiayi Yang
- College of Life Sciences, TaiKang Center for Life and Medical Sciences, RNA InstituteWuhan UniversityWuhanChina
| | - Weiliang Fan
- College of Life Sciences, TaiKang Center for Life and Medical Sciences, RNA InstituteWuhan UniversityWuhanChina
| | - Yong‐Zhen Xu
- College of Life Sciences, TaiKang Center for Life and Medical Sciences, RNA InstituteWuhan UniversityWuhanChina
| | - Hong Cheng
- Key Laboratory of RNA Science and Engineering, Chinese Academy of Sciences, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of SciencesUniversity of Chinese Academy of SciencesShanghaiChina
| | - Yu Zhou
- College of Life Sciences, TaiKang Center for Life and Medical Sciences, RNA InstituteWuhan UniversityWuhanChina
- Frontier Science Center for Immunology and MetabolismWuhan UniversityWuhanChina
- Institute of Advanced StudiesWuhan UniversityWuhanChina
- State Key Laboratory of VirologyWuhan UniversityWuhanChina
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17
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Galang JN, Shen Y, Koitzsch U, Yu X, Eischeid-Scholz H, Bachurski D, Rau TT, Neppl C, Herling M, Bulimaga B, Vasyutina E, Schweiger MR, Büttner R, Odenthal M, Anokhina MM. Vesicular Release and Uptake of Circular LSD1-RNAs from Non-Cancer and Cancer Lung Cells. Int J Mol Sci 2023; 24:13981. [PMID: 37762282 PMCID: PMC10530930 DOI: 10.3390/ijms241813981] [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: 07/23/2023] [Revised: 09/03/2023] [Accepted: 09/07/2023] [Indexed: 09/29/2023] Open
Abstract
Lysine-specific demethylase 1 (LSD1) is highly expressed in many cancer types and strongly associated with cancer progression and metastasis. Circular RNAs (circRNAs) are produced by back-splicing and influence the interactive RNA network by microRNA and protein sponging. In the present study, we aimedto identify circRNAs that derive from the LSD1-encoding KDM1A gene, and to investigate their potential to be released and uptaken by lung cancer versus non-cancer epithelial cells. We identified four circLSD1-RNAs by RT-PCR with divergent primers, followed by sequencing. The expression level of circLSD1-RNAs was then studied by quantitative PCR on cellular and extracellular fractions of lung cancer (PC9) and non-cancer primary small airway epithelial (PSAE) cells. Moreover, we established the transgenic overexpression of circLSD1-RNAs. We show that circLSD1-RNAs are primarily located in the cytoplasm, but are packaged and released from lung cancer and non-cancer cells by extracellular vesicles (EVs) and ribonucleoprotein (RNP) complexes, respectively. Proteomics demonstrated a different protein pattern of EV fractions released from PC9 versus PSAE cells. Importantly, released circLSD1-RNAs were differently taken up by PSAE and PC9 cells. In conclusion, our findings provide primary evidence that circLSD1-RNAs participate in the intercellular communication of lung cancer cells with the tumor environment.
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Affiliation(s)
- Joelle Noriko Galang
- Institute of Pathology, University Hospital of Cologne, 50937 Cologne, Germany; (J.N.G.); (Y.S.); (X.Y.); (H.E.-S.); (B.B.); (R.B.)
- Center for Molecular Medicine Cologne, University of Cologne, 50937 Cologne, Germany;
| | - Yefeng Shen
- Institute of Pathology, University Hospital of Cologne, 50937 Cologne, Germany; (J.N.G.); (Y.S.); (X.Y.); (H.E.-S.); (B.B.); (R.B.)
- Center for Molecular Medicine Cologne, University of Cologne, 50937 Cologne, Germany;
| | - Ulrike Koitzsch
- Institute of Pathology, University Hospital of Cologne, 50937 Cologne, Germany; (J.N.G.); (Y.S.); (X.Y.); (H.E.-S.); (B.B.); (R.B.)
- Center for Molecular Medicine Cologne, University of Cologne, 50937 Cologne, Germany;
| | - Xiaojie Yu
- Institute of Pathology, University Hospital of Cologne, 50937 Cologne, Germany; (J.N.G.); (Y.S.); (X.Y.); (H.E.-S.); (B.B.); (R.B.)
- Center for Molecular Medicine Cologne, University of Cologne, 50937 Cologne, Germany;
| | - Hannah Eischeid-Scholz
- Institute of Pathology, University Hospital of Cologne, 50937 Cologne, Germany; (J.N.G.); (Y.S.); (X.Y.); (H.E.-S.); (B.B.); (R.B.)
- Center for Molecular Medicine Cologne, University of Cologne, 50937 Cologne, Germany;
| | - Daniel Bachurski
- CECAD Center of Excellence on Cellular Stress Responses in Aging-Associated Diseases, University of Cologne, 50937 Cologne, Germany;
- Department I of Internal Medicine, University Hospital of Cologne, 50937 Cologne, Germany; (M.H.)
| | - Tilman T. Rau
- Institute of Pathology, University Hospital of Duesseldorf, 40225 Duesseldorf, Germany; (T.T.R.); (C.N.)
| | - Christina Neppl
- Institute of Pathology, University Hospital of Duesseldorf, 40225 Duesseldorf, Germany; (T.T.R.); (C.N.)
| | - Marco Herling
- Department I of Internal Medicine, University Hospital of Cologne, 50937 Cologne, Germany; (M.H.)
- Department of Hematology, Cellular Therapy and Hemostaseology, University of Leipzig, 04103 Leipzig, Germany
| | - Bianca Bulimaga
- Institute of Pathology, University Hospital of Cologne, 50937 Cologne, Germany; (J.N.G.); (Y.S.); (X.Y.); (H.E.-S.); (B.B.); (R.B.)
- Center for Molecular Medicine Cologne, University of Cologne, 50937 Cologne, Germany;
| | - Elena Vasyutina
- Department I of Internal Medicine, University Hospital of Cologne, 50937 Cologne, Germany; (M.H.)
- Department of Hematology, Cellular Therapy and Hemostaseology, University of Leipzig, 04103 Leipzig, Germany
| | - Michal R. Schweiger
- Center for Molecular Medicine Cologne, University of Cologne, 50937 Cologne, Germany;
- Institute for Epigenetics, University Hospital of Cologne, 50937 Cologne, Germany
| | - Reinhard Büttner
- Institute of Pathology, University Hospital of Cologne, 50937 Cologne, Germany; (J.N.G.); (Y.S.); (X.Y.); (H.E.-S.); (B.B.); (R.B.)
- Center for Molecular Medicine Cologne, University of Cologne, 50937 Cologne, Germany;
| | - Margarete Odenthal
- Institute of Pathology, University Hospital of Cologne, 50937 Cologne, Germany; (J.N.G.); (Y.S.); (X.Y.); (H.E.-S.); (B.B.); (R.B.)
- Center for Molecular Medicine Cologne, University of Cologne, 50937 Cologne, Germany;
| | - Maria M. Anokhina
- Institute of Pathology, University Hospital of Cologne, 50937 Cologne, Germany; (J.N.G.); (Y.S.); (X.Y.); (H.E.-S.); (B.B.); (R.B.)
- Center for Molecular Medicine Cologne, University of Cologne, 50937 Cologne, Germany;
- Institute of Pathology, University Hospital of Duesseldorf, 40225 Duesseldorf, Germany; (T.T.R.); (C.N.)
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18
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Flemr M, Schwaiger M, Hess D, Iesmantavicius V, Ahel J, Tuck AC, Mohn F, Bühler M. Mouse nuclear RNAi-defective 2 promotes splicing of weak 5' splice sites. RNA (NEW YORK, N.Y.) 2023; 29:1140-1165. [PMID: 37137667 PMCID: PMC10351895 DOI: 10.1261/rna.079465.122] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Accepted: 04/19/2023] [Indexed: 05/05/2023]
Abstract
Removal of introns during pre-mRNA splicing, which is central to gene expression, initiates by base pairing of U1 snRNA with a 5' splice site (5'SS). In mammals, many introns contain weak 5'SSs that are not efficiently recognized by the canonical U1 snRNP, suggesting alternative mechanisms exist. Here, we develop a cross-linking immunoprecipitation coupled to a high-throughput sequencing method, BCLIP-seq, to identify NRDE2 (nuclear RNAi-defective 2), and CCDC174 (coiled-coil domain-containing 174) as novel RNA-binding proteins in mouse ES cells that associate with U1 snRNA and 5'SSs. Both proteins bind directly to U1 snRNA independently of canonical U1 snRNP-specific proteins, and they are required for the selection and effective processing of weak 5'SSs. Our results reveal that mammalian cells use noncanonical splicing factors bound directly to U1 snRNA to effectively select suboptimal 5'SS sequences in hundreds of genes, promoting proper splice site choice, and accurate pre-mRNA splicing.
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Affiliation(s)
- Matyas Flemr
- Friedrich Miescher Institute for Biomedical Research, 4058 Basel, Switzerland
| | - Michaela Schwaiger
- Friedrich Miescher Institute for Biomedical Research, 4058 Basel, Switzerland
- Swiss Institute of Bioinformatics, 4058 Basel, Switzerland
| | - Daniel Hess
- Friedrich Miescher Institute for Biomedical Research, 4058 Basel, Switzerland
| | | | - Josip Ahel
- Friedrich Miescher Institute for Biomedical Research, 4058 Basel, Switzerland
| | - Alex Charles Tuck
- Friedrich Miescher Institute for Biomedical Research, 4058 Basel, Switzerland
| | - Fabio Mohn
- Friedrich Miescher Institute for Biomedical Research, 4058 Basel, Switzerland
| | - Marc Bühler
- Friedrich Miescher Institute for Biomedical Research, 4058 Basel, Switzerland
- University of Basel, 4003 Basel, Switzerland
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19
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Xiao W, Yeom KH, Lin CH, Black DL. Improved enzymatic labeling of fluorescent in situ hybridization probes applied to the visualization of retained introns in cells. RNA (NEW YORK, N.Y.) 2023; 29:1274-1287. [PMID: 37130703 PMCID: PMC10351894 DOI: 10.1261/rna.079591.123] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/2023] [Accepted: 03/31/2023] [Indexed: 05/04/2023]
Abstract
Fluorescence in situ hybridization (FISH) is a widely used tool for quantifying gene expression and determining the location of RNA molecules in cells. We present an improved method for FISH probe production that yields high-purity probes with a wide range of fluorophores using standard laboratory equipment at low cost. The method modifies an earlier protocol that uses terminal deoxynucleotidyl transferase to add fluorescently labeled nucleotides to synthetic deoxyoligonucleotides. In our protocol, amino-11-ddUTP is joined to an oligonucleotide pool prior to its conjugation to a fluorescent dye, thereby generating pools of probes ready for a variety of modifications. This order of reaction steps allows for high labeling efficiencies regardless of the GC content or terminal base of the oligonucleotides. The degree of labeling (DOL) for spectrally distinct fluorophores (Quasar, ATTO, and Alexa dyes) was mostly >90%, comparable with commercial probes. The ease and low cost of production allowed the generation of probe sets targeting a wide variety of RNA molecules. Using these probes, FISH assays in C2C12 cells showed the expected subcellular localization of mRNAs and pre-mRNAs for Polr2a (RNA polymerase II subunit 2a) and Gapdh, and of the long noncoding RNAs Malat1 and Neat1 Developing FISH probe sets for several transcripts containing retained introns, we found that retained introns in the Gabbr1 and Noc2l transcripts are present in subnuclear foci separate from their sites of synthesis and partially coincident with nuclear speckles. This labeling protocol should have many applications in RNA biology.
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Affiliation(s)
- Wen Xiao
- Department of Microbiology, Immunology, and Molecular Genetics, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California 90095, USA
| | - Kyu-Hyeon Yeom
- Department of Microbiology, Immunology, and Molecular Genetics, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California 90095, USA
| | - Chia-Ho Lin
- Department of Microbiology, Immunology, and Molecular Genetics, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California 90095, USA
| | - Douglas L Black
- Department of Microbiology, Immunology, and Molecular Genetics, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California 90095, USA
- Molecular Biology Institute, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California 90095, USA
- Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California 90095, USA
- Jonsson Comprehensive Cancer Center, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California 90095, USA
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20
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Wu S, Chen J, Teo BHD, Wee SYK, Wong MHM, Cui J, Chen J, Leong KP, Lu J. The axis of complement C1 and nucleolus in antinuclear autoimmunity. Front Immunol 2023; 14:1196544. [PMID: 37359557 PMCID: PMC10288996 DOI: 10.3389/fimmu.2023.1196544] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Accepted: 05/19/2023] [Indexed: 06/28/2023] Open
Abstract
Antinuclear autoantibodies (ANA) are heterogeneous self-reactive antibodies that target the chromatin network, the speckled, the nucleoli, and other nuclear regions. The immunological aberration for ANA production remains partially understood, but ANA are known to be pathogenic, especially, in systemic lupus erythematosus (SLE). Most SLE patients exhibit a highly polygenic disease involving multiple organs, but in rare complement C1q, C1r, or C1s deficiencies, the disease can become largely monogenic. Increasing evidence point to intrinsic autoimmunogenicity of the nuclei. Necrotic cells release fragmented chromatins as nucleosomes and the alarmin HMGB1 is associated with the nucleosomes to activate TLRs and confer anti-chromatin autoimmunogenecity. In speckled regions, the major ANA targets Sm/RNP and SSA/Ro contain snRNAs that confer autoimmunogenecity to Sm/RNP and SSA/Ro antigens. Recently, three GAR/RGG-containing alarmins have been identified in the nucleolus that helps explain its high autoimmunogenicity. Interestingly, C1q binds to the nucleoli exposed by necrotic cells to cause protease C1r and C1s activation. C1s cleaves HMGB1 to inactive its alarmin activity. C1 proteases also degrade many nucleolar autoantigens including nucleolin, a major GAR/RGG-containing autoantigen and alarmin. It appears that the different nuclear regions are intrinsically autoimmunogenic by containing autoantigens and alarmins. However, the extracellular complement C1 complex function to dampen nuclear autoimmunogenecity by degrading these nuclear proteins.
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Affiliation(s)
- Shan Wu
- Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
- Immunology Translational Research Program, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Junjie Chen
- Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
- Immunology Translational Research Program, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Boon Heng Dennis Teo
- Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
- Immunology Translational Research Program, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Seng Yin Kelly Wee
- Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
- Immunology Translational Research Program, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Ming Hui Millie Wong
- Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
- Immunology Translational Research Program, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Jianzhou Cui
- Immunology Translational Research Program, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Jinmiao Chen
- Immunology Translational Research Program, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
- Singapore Immunology Network, Agency for Science, Technology and Research, Singapore, Singapore
| | - Khai Pang Leong
- Department of Rheumatology, Allergy and Immunology, Tan Tock Seng Hospital, Singapore, Singapore
| | - Jinhua Lu
- Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
- Immunology Translational Research Program, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
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21
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Wojtyś W, Oroń M. How Driver Oncogenes Shape and Are Shaped by Alternative Splicing Mechanisms in Tumors. Cancers (Basel) 2023; 15:cancers15112918. [PMID: 37296881 DOI: 10.3390/cancers15112918] [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: 04/28/2023] [Revised: 05/20/2023] [Accepted: 05/24/2023] [Indexed: 06/12/2023] Open
Abstract
The development of RNA sequencing methods has allowed us to study and better understand the landscape of aberrant pre-mRNA splicing in tumors. Altered splicing patterns are observed in many different tumors and affect all hallmarks of cancer: growth signal independence, avoidance of apoptosis, unlimited proliferation, invasiveness, angiogenesis, and metabolism. In this review, we focus on the interplay between driver oncogenes and alternative splicing in cancer. On one hand, oncogenic proteins-mutant p53, CMYC, KRAS, or PI3K-modify the alternative splicing landscape by regulating expression, phosphorylation, and interaction of splicing factors with spliceosome components. Some splicing factors-SRSF1 and hnRNPA1-are also driver oncogenes. At the same time, aberrant splicing activates key oncogenes and oncogenic pathways: p53 oncogenic isoforms, the RAS-RAF-MAPK pathway, the PI3K-mTOR pathway, the EGF and FGF receptor families, and SRSF1 splicing factor. The ultimate goal of cancer research is a better diagnosis and treatment of cancer patients. In the final part of this review, we discuss present therapeutic opportunities and possible directions of further studies aiming to design therapies targeting alternative splicing mechanisms in the context of driver oncogenes.
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Affiliation(s)
- Weronika Wojtyś
- Laboratory of Human Disease Multiomics, Mossakowski Medical Research Institute, Polish Academy of Sciences, Pawinskiego 5, 02-106 Warsaw, Poland
| | - Magdalena Oroń
- Laboratory of Human Disease Multiomics, Mossakowski Medical Research Institute, Polish Academy of Sciences, Pawinskiego 5, 02-106 Warsaw, Poland
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22
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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: 50] [Impact Index Per Article: 50.0] [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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23
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Miyashita A, Kobayashi M, Yokota T, Zochodne DW. Diabetic Polyneuropathy: New Strategies to Target Sensory Neurons in Dorsal Root Ganglia. Int J Mol Sci 2023; 24:ijms24065977. [PMID: 36983051 PMCID: PMC10051459 DOI: 10.3390/ijms24065977] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Revised: 03/10/2023] [Accepted: 03/11/2023] [Indexed: 03/29/2023] Open
Abstract
Diabetic polyneuropathy (DPN) is the most common type of diabetic neuropathy, rendering a slowly progressive, symmetrical, and length-dependent dying-back axonopathy with preferential sensory involvement. Although the pathogenesis of DPN is complex, this review emphasizes the concept that hyperglycemia and metabolic stressors directly target sensory neurons in the dorsal root ganglia (DRG), leading to distal axonal degeneration. In this context, we discuss the role for DRG-targeting gene delivery, specifically oligonucleotide therapeutics for DPN. Molecules including insulin, GLP-1, PTEN, HSP27, RAGE, CWC22, and DUSP1 that impact neurotrophic signal transduction (for example, phosphatidylinositol-3 kinase/phosphorylated protein kinase B [PI3/pAkt] signaling) and other cellular networks may promote regeneration. Regenerative strategies may be essential in maintaining axon integrity during ongoing degeneration in diabetes mellitus (DM). We discuss specific new findings that relate to sensory neuron function in DM associated with abnormal dynamics of nuclear bodies such as Cajal bodies and nuclear speckles in which mRNA transcription and post-transcriptional processing occur. Manipulating noncoding RNAs such as microRNA and long-noncoding RNA (specifically MALAT1) that regulate gene expression through post-transcriptional modification are interesting avenues to consider in supporting neurons during DM. Finally, we present therapeutic possibilities around the use of a novel DNA/RNA heteroduplex oligonucleotide that provides more efficient gene knockdown in DRG than the single-stranded antisense oligonucleotide.
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Affiliation(s)
- Akiko Miyashita
- Department of Neurology, Neurological Science, Tokyo Medical and Dental University, Tokyo 113-8519, Japan
- Center for Brain Integration Research, Tokyo Medical and Dental University, Tokyo 113-8519, Japan
| | - Masaki Kobayashi
- Department of Neurology, Neurological Science, Tokyo Medical and Dental University, Tokyo 113-8519, Japan
- Center for Brain Integration Research, Tokyo Medical and Dental University, Tokyo 113-8519, Japan
- Department of Neurology, Nissan Tamagawa Hospital, Tokyo 158-0095, Japan
| | - Takanori Yokota
- Department of Neurology, Neurological Science, Tokyo Medical and Dental University, Tokyo 113-8519, Japan
- Center for Brain Integration Research, Tokyo Medical and Dental University, Tokyo 113-8519, Japan
| | - Douglas W. Zochodne
- Division of Neurology and Department of Medicine, Faculty of Medicine and Dentistry, The Neuroscience and Mental Health Institute and The Alberta Diabetes Institute, University of Alberta, Edmonton, AB T6G 2G3, Canada
- Correspondence: ; Tel.: +1-780-248-1928; Fax: +1-780-248-1807
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24
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Zhang S, Cooper JAL, Chong YS, Naveed A, Mayoh C, Jayatilleke N, Liu T, Amos S, Kobelke S, Marshall AC, Meers O, Choi YS, Bond CS, Fox AH. NONO enhances mRNA processing of super-enhancer-associated GATA2 and HAND2 genes in neuroblastoma. EMBO Rep 2023; 24:e54977. [PMID: 36416237 PMCID: PMC9900351 DOI: 10.15252/embr.202254977] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2022] [Revised: 11/02/2022] [Accepted: 11/07/2022] [Indexed: 11/24/2022] Open
Abstract
High-risk neuroblastoma patients have poor survival rates and require better therapeutic options. High expression of a multifunctional DNA and RNA-binding protein, NONO, in neuroblastoma is associated with poor patient outcome; however, there is little understanding of the mechanism of NONO-dependent oncogenic gene regulatory activity in neuroblastoma. Here, we used cell imaging, biochemical and genome-wide molecular analysis to reveal complex NONO-dependent regulation of gene expression. NONO forms RNA- and DNA-tethered condensates throughout the nucleus and undergoes phase separation in vitro, modulated by nucleic acid binding. CLIP analyses show that NONO mainly binds to the 5' end of pre-mRNAs and modulates pre-mRNA processing, dependent on its RNA-binding activity. NONO regulates super-enhancer-associated genes, including HAND2 and GATA2. Abrogating NONO RNA binding, or phase separation activity, results in decreased expression of HAND2 and GATA2. Thus, future development of agents that target RNA-binding activity of NONO may have therapeutic potential in this cancer context.
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Affiliation(s)
- Song Zhang
- School of Human SciencesThe University of Western AustraliaCrawleyWAAustralia
| | - Jack AL Cooper
- School of Human SciencesThe University of Western AustraliaCrawleyWAAustralia
| | - Yee Seng Chong
- School of Molecular SciencesThe University of Western AustraliaCrawleyWAAustralia
| | - Alina Naveed
- School of Human SciencesThe University of Western AustraliaCrawleyWAAustralia
| | - Chelsea Mayoh
- Children's Cancer Institute AustraliaRandwickNSWAustralia
- Centre for Childhood Cancer ResearchUNSW SydneyKensingtonNSWAustralia
- School of Women's and Children's HealthUNSW SydneyKensingtonNSWAustralia
| | - Nisitha Jayatilleke
- Children's Cancer Institute AustraliaRandwickNSWAustralia
- Centre for Childhood Cancer ResearchUNSW SydneyKensingtonNSWAustralia
| | - Tao Liu
- Children's Cancer Institute AustraliaRandwickNSWAustralia
- Centre for Childhood Cancer ResearchUNSW SydneyKensingtonNSWAustralia
| | - Sebastian Amos
- School of Human SciencesThe University of Western AustraliaCrawleyWAAustralia
| | - Simon Kobelke
- School of Human SciencesThe University of Western AustraliaCrawleyWAAustralia
| | - Andrew C Marshall
- School of Molecular SciencesThe University of Western AustraliaCrawleyWAAustralia
| | - Oliver Meers
- School of Human SciencesThe University of Western AustraliaCrawleyWAAustralia
| | - Yu Suk Choi
- School of Human SciencesThe University of Western AustraliaCrawleyWAAustralia
| | - Charles S Bond
- School of Molecular SciencesThe University of Western AustraliaCrawleyWAAustralia
| | - Archa H Fox
- School of Human SciencesThe University of Western AustraliaCrawleyWAAustralia
- School of Molecular SciencesThe University of Western AustraliaCrawleyWAAustralia
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25
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Vester K, Preußner M, Holton N, Feng S, Schultz C, Heyd F, Wahl MC. Recruitment of a splicing factor to the nuclear lamina for its inactivation. Commun Biol 2022; 5:736. [PMID: 35869234 PMCID: PMC9307855 DOI: 10.1038/s42003-022-03689-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2022] [Accepted: 07/08/2022] [Indexed: 11/10/2022] Open
Abstract
Precursor messenger RNA splicing is a highly regulated process, mediated by a complex RNA-protein machinery, the spliceosome, that encompasses several hundred proteins and five small nuclear RNAs in humans. Emerging evidence suggests that the spatial organization of splicing factors and their spatio-temporal dynamics participate in the regulation of splicing. So far, methods to manipulate the spatial distribution of splicing factors in a temporally defined manner in living cells are missing. Here, we describe such an approach that takes advantage of a reversible chemical dimerizer, and outline the requirements for efficient, reversible re-localization of splicing factors to selected sub-nuclear compartments. In a proof-of-principle study, the partial re-localization of the PRPF38A protein to the nuclear lamina in HEK293T cells induced a moderate increase in intron retention. Our approach allows fast and reversible re-localization of splicing factors, has few side effects and can be applied to many splicing factors by fusion of a protein tag through genome engineering. Apart from the systematic analysis of the spatio-temporal aspects of splicing regulation, the approach has a large potential for the fast induction and reversal of splicing switches and can reveal mechanisms of splicing regulation in native nuclear environments. Through the use of a reversible chemical dimerizer, the splicing factor PRPF38A is re-localized to the nuclear lamina, paving the way for a systematic analysis of spatio-temporal splicing regulation.
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26
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A Truncated Form of the p27 Cyclin-Dependent Kinase Inhibitor Translated from Pre-mRNA Causes G 2-Phase Arrest. Mol Cell Biol 2022; 42:e0021722. [PMID: 36317925 PMCID: PMC9671031 DOI: 10.1128/mcb.00217-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Pre-mRNA splicing is an indispensable mechanism for eukaryotic gene expression. Splicing inhibition causes cell cycle arrest at the G1 and G2/M phases, and this is thought to be one of the reasons for the potent antitumor activity of splicing inhibitors. However, the molecular mechanisms underlying the cell cycle arrest have many unknown aspects. In particular, the mechanism of G2/M-phase arrest caused by splicing inhibition is completely unknown. Here, we found that lower and higher concentrations of pladienolide B caused M-phase and G2-phase arrest, respectively. We analyzed protein levels of cell cycle regulators and found that a truncated form of the p27 cyclin-dependent kinase inhibitor, named p27*, accumulated in G2-arrested cells. Overexpression of p27* caused partial G2-phase arrest. Conversely, knockdown of p27* accelerated exit from G2/M phase after washout of splicing inhibitor. These results suggest that p27* contributes to G2/M-phase arrest caused by splicing inhibition. We also found that p27* bound to and inhibited M-phase cyclins, although it is well known that p27 regulates the G1/S transition. Intriguingly, p27*, but not full-length p27, was resistant to proteasomal degradation and remained in G2/M phase. These results suggest that p27*, which is a very stable truncated protein in G2/M phase, contributes to G2-phase arrest caused by splicing inhibition.
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27
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David JK, Maden SK, Wood MA, Thompson RF, Nellore A. Retained introns in long RNA-seq reads are not reliably detected in sample-matched short reads. Genome Biol 2022; 23:240. [PMID: 36369064 PMCID: PMC9652823 DOI: 10.1186/s13059-022-02789-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Accepted: 10/10/2022] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND There is growing interest in retained introns in a variety of disease contexts including cancer and aging. Many software tools have been developed to detect retained introns from short RNA-seq reads, but reliable detection is complicated by overlapping genes and transcripts as well as the presence of unprocessed or partially processed RNAs. RESULTS We compared introns detected by 8 tools using short RNA-seq reads with introns observed in long RNA-seq reads from the same biological specimens. We found significant disagreement among tools (Fleiss' [Formula: see text]) such that 47.7% of all detected intron retentions were not called by more than one tool. We also observed poor performance of all tools, with none achieving an F1-score greater than 0.26, and qualitatively different behaviors between general-purpose alternative splicing detection tools and tools confined to retained intron detection. CONCLUSIONS Short-read tools detect intron retention with poor recall and precision, calling into question the completeness and validity of a large percentage of putatively retained introns called by commonly used methods.
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Affiliation(s)
- Julianne K. David
- grid.5288.70000 0000 9758 5690Computational Biology Program, Oregon Health & Science University, Portland, OR USA ,grid.5288.70000 0000 9758 5690Department of Biomedical Engineering, Oregon Health & Science University, Portland, OR USA ,Present Address: Base5 Genomics, Inc., Mountain View, CA USA
| | - Sean K. Maden
- grid.5288.70000 0000 9758 5690Computational Biology Program, Oregon Health & Science University, Portland, OR USA ,grid.5288.70000 0000 9758 5690Department of Biomedical Engineering, Oregon Health & Science University, Portland, OR USA ,grid.21107.350000 0001 2171 9311Present Address: Department of Biostatistics, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD USA
| | - Mary A. Wood
- grid.5288.70000 0000 9758 5690Computational Biology Program, Oregon Health & Science University, Portland, OR USA ,grid.429936.30000 0004 5914 210XPortland VA Research Foundation, Portland, OR USA ,Present Address: Phase Genomics, Inc., Seattle, WA USA
| | - Reid F. Thompson
- grid.5288.70000 0000 9758 5690Computational Biology Program, Oregon Health & Science University, Portland, OR USA ,grid.5288.70000 0000 9758 5690Department of Biomedical Engineering, Oregon Health & Science University, Portland, OR USA ,grid.484322.bDivision of Hospital and Specialty Medicine, VA Portland Healthcare System, Portland, OR USA ,grid.5288.70000 0000 9758 5690Department of Medical Informatics & Clinical Epidemiology, Oregon Health & Science University, Portland, OR USA ,grid.5288.70000 0000 9758 5690Department of Radiation Medicine, Oregon Health & Science University, Portland, OR USA
| | - Abhinav Nellore
- grid.5288.70000 0000 9758 5690Computational Biology Program, Oregon Health & Science University, Portland, OR USA ,grid.5288.70000 0000 9758 5690Department of Biomedical Engineering, Oregon Health & Science University, Portland, OR USA ,grid.5288.70000 0000 9758 5690Department of Surgery, Oregon Health & Science University, Portland, OR USA
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28
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Cancer cells hijack RNA processing to rewrite the message. Biochem Soc Trans 2022; 50:1447-1456. [PMID: 36282006 PMCID: PMC9704515 DOI: 10.1042/bst20220621] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2022] [Revised: 10/01/2022] [Accepted: 10/04/2022] [Indexed: 11/17/2022]
Abstract
Typically, cancer is thought to arise due to DNA mutations, dysregulated transcription and/or aberrant signalling. Recently, it has become clear that dysregulated mRNA processing, mRNA export and translation also contribute to malignancy. RNA processing events result in major modifications to the physical nature of mRNAs such as the addition of the methyl-7-guanosine cap, the removal of introns and the addition of polyA tails. mRNA processing is a critical determinant for the protein-coding capacity of mRNAs since these physical changes impact the efficiency by which a given transcript can be exported to the cytoplasm and translated into protein. While many of these mRNA metabolism steps were considered constitutive housekeeping activities, they are now known to be highly regulated with combinatorial and multiplicative impacts i.e. one event will influence the capacity to undergo others. Furthermore, alternative splicing and/or cleavage and polyadenylation can produce transcripts with alternative messages and new functionalities. The coordinated processing of groups of functionally related RNAs can potently re-wire signalling pathways, modulate survival pathways and even re-structure the cell. As postulated by the RNA regulon model, combinatorial regulation of these groups is achieved by the presence of shared cis-acting elements (known as USER codes) which recruit machinery for processing, export or translation. In all, dysregulated RNA metabolism in cancer gives rise to an altered proteome that in turn elicits biological responses related to malignancy. Studies of these events in cancer revealed new mechanisms underpinning malignancies and unearthed novel therapeutic opportunities. In all, cancer cells coopt RNA processing, export and translation to support their oncogenic activity.
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29
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Hluchý M, Gajdušková P, Ruiz de Los Mozos I, Rájecký M, Kluge M, Berger BT, Slabá Z, Potěšil D, Weiß E, Ule J, Zdráhal Z, Knapp S, Paruch K, Friedel CC, Blazek D. CDK11 regulates pre-mRNA splicing by phosphorylation of SF3B1. Nature 2022; 609:829-834. [PMID: 36104565 DOI: 10.1038/s41586-022-05204-z] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2021] [Accepted: 08/08/2022] [Indexed: 11/09/2022]
Abstract
RNA splicing, the process of intron removal from pre-mRNA, is essential for the regulation of gene expression. It is controlled by the spliceosome, a megadalton RNA-protein complex that assembles de novo on each pre-mRNA intron through an ordered assembly of intermediate complexes1,2. Spliceosome activation is a major control step that requires substantial protein and RNA rearrangements leading to a catalytically active complex1-5. Splicing factor 3B subunit 1 (SF3B1) protein-a subunit of the U2 small nuclear ribonucleoprotein6-is phosphorylated during spliceosome activation7-10, but the kinase that is responsible has not been identified. Here we show that cyclin-dependent kinase 11 (CDK11) associates with SF3B1 and phosphorylates threonine residues at its N terminus during spliceosome activation. The phosphorylation is important for the association between SF3B1 and U5 and U6 snRNAs in the activated spliceosome, termed the Bact complex, and the phosphorylation can be blocked by OTS964, a potent and selective inhibitor of CDK11. Inhibition of CDK11 prevents spliceosomal transition from the precatalytic complex B to the activated complex Bact and leads to widespread intron retention and accumulation of non-functional spliceosomes on pre-mRNAs and chromatin. We demonstrate a central role of CDK11 in spliceosome assembly and splicing regulation and characterize OTS964 as a highly selective CDK11 inhibitor that suppresses spliceosome activation and splicing.
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Affiliation(s)
- Milan Hluchý
- Central European Institute of Technology (CEITEC), Masaryk University, Brno, Czech Republic
| | - Pavla Gajdušková
- Central European Institute of Technology (CEITEC), Masaryk University, Brno, Czech Republic
| | - Igor Ruiz de Los Mozos
- The Francis Crick Institute, London, UK
- Department of Personalized Medicine, NASERTIC, Government of Navarra, Pamplona, Spain
- Center for Applied Medical Research, University of Navarra, Pamplona, Spain
| | - Michal Rájecký
- Central European Institute of Technology (CEITEC), Masaryk University, Brno, Czech Republic
| | - Michael Kluge
- Institut für Informatik, Ludwig-Maximilians-Universität München, München, Germany
| | - Benedict-Tilman Berger
- Structural Genomics Consortium (SGC), Buchmann Institute for Life Sciences (BMLS), Goethe University Frankfurt am Main, Frankfurt am Main, Germany
- Institut für Pharmazeutische Chemie, Goethe University Frankfurt am Main, Frankfurt am Main, Germany
| | - Zuzana Slabá
- Central European Institute of Technology (CEITEC), Masaryk University, Brno, Czech Republic
| | - David Potěšil
- Central European Institute of Technology (CEITEC), Masaryk University, Brno, Czech Republic
| | - Elena Weiß
- Institut für Informatik, Ludwig-Maximilians-Universität München, München, Germany
| | - Jernej Ule
- The Francis Crick Institute, London, UK
- UK Dementia Research Institute, King's College London, London, UK
| | - Zbyněk Zdráhal
- Central European Institute of Technology (CEITEC), Masaryk University, Brno, Czech Republic
| | - Stefan Knapp
- Structural Genomics Consortium (SGC), Buchmann Institute for Life Sciences (BMLS), Goethe University Frankfurt am Main, Frankfurt am Main, Germany
- Institut für Pharmazeutische Chemie, Goethe University Frankfurt am Main, Frankfurt am Main, Germany
| | - Kamil Paruch
- Department of Chemistry, Faculty of Science, Masaryk University, Brno, Czech Republic
- International Clinical Research Center, St Anne's University Hospital in Brno, Brno, Czech Republic
| | - Caroline C Friedel
- Institut für Informatik, Ludwig-Maximilians-Universität München, München, Germany
| | - Dalibor Blazek
- Central European Institute of Technology (CEITEC), Masaryk University, Brno, Czech Republic.
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Cytoplasmic forces functionally reorganize nuclear condensates in oocytes. Nat Commun 2022; 13:5070. [PMID: 36038550 PMCID: PMC9424315 DOI: 10.1038/s41467-022-32675-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2022] [Accepted: 08/05/2022] [Indexed: 12/21/2022] Open
Abstract
Cells remodel their cytoplasm with force-generating cytoskeletal motors. Their activity generates random forces that stir the cytoplasm, agitating and displacing membrane-bound organelles like the nucleus in somatic and germ cells. These forces are transmitted inside the nucleus, yet their consequences on liquid-like biomolecular condensates residing in the nucleus remain unexplored. Here, we probe experimentally and computationally diverse nuclear condensates, that include nuclear speckles, Cajal bodies, and nucleoli, during cytoplasmic remodeling of female germ cells named oocytes. We discover that growing mammalian oocytes deploy cytoplasmic forces to timely impose multiscale reorganization of nuclear condensates for the success of meiotic divisions. These cytoplasmic forces accelerate nuclear condensate collision-coalescence and molecular kinetics within condensates. Disrupting the forces decelerates nuclear condensate reorganization on both scales, which correlates with compromised condensate-associated mRNA processing and hindered oocyte divisions that drive female fertility. We establish that cytoplasmic forces can reorganize nuclear condensates in an evolutionary conserved fashion in insects. Our work implies that cells evolved a mechanism, based on cytoplasmic force tuning, to functionally regulate a broad range of nuclear condensates across scales. This finding opens new perspectives when studying condensate-associated pathologies like cancer, neurodegeneration and viral infections. Cytoskeletal activity generates mechanical forces known to agitate and displace membrane-bound organelles in the cytoplasm. In oocytes, Al Jord et al. discover that these cytoplasmic forces functionally remodel nuclear RNA-processing condensates across scales for developmental success.
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Esparza M, Bhat P, Fontoura BMA. Viral-host interactions during splicing and nuclear export of influenza virus mRNAs. Curr Opin Virol 2022; 55:101254. [PMID: 35908311 PMCID: PMC9945342 DOI: 10.1016/j.coviro.2022.101254] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2022] [Revised: 06/23/2022] [Accepted: 06/30/2022] [Indexed: 02/07/2023]
Abstract
As influenza-A viruses (IAV) replicate in the host cell nucleus, intranuclear pathways are usurped for viral gene expression. The eight genomic viral ribonucleoproteins (vRNPs) segments of IAV are transcribed and two generate viral mRNAs (M and NS) that undergo alternative splicing followed by export from the nucleus. The focus of this review is on viral RNA splicing and nuclear export. Recent mechanistic advances on M and NS splicing show differential regulation by RNA-binding proteins as well as distinct intranuclear localization. After a review of IAV splicing, we will discuss the nuclear export of viral mRNAs, which occur by interacting with specific constituents of the host mRNA export machinery that translocate viral mRNAs through the nuclear pore complex for translation in the cytoplasm.
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Kaczynski TJ, Au ED, Farkas MH. Exploring the lncRNA localization landscape within the retinal pigment epithelium under normal and stress conditions. BMC Genomics 2022; 23:539. [PMID: 35883037 PMCID: PMC9327364 DOI: 10.1186/s12864-022-08777-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2022] [Accepted: 07/14/2022] [Indexed: 11/20/2022] Open
Abstract
Background Long noncoding RNAs (lncRNAs) are emerging as a class of genes whose importance has yet to be fully realized. It is becoming clear that the primary function of lncRNAs is to regulate gene expression, and they do so through a variety of mechanisms that are critically tied to their subcellular localization. Although most lncRNAs are poorly understood, mapping lncRNA subcellular localization can provide a foundation for understanding these mechanisms. Results Here, we present an initial step toward uncovering the localization landscape of lncRNAs in the human retinal pigment epithelium (RPE) using high throughput RNA-Sequencing (RNA-Seq). To do this, we differentiated human induced pluripotent stem cells (iPSCs) into RPE, isolated RNA from nuclear and cytoplasmic fractions, and performed RNA-Seq on both. Furthermore, we investigated lncRNA localization changes that occur in response to oxidative stress. We discovered that, under normal conditions, most lncRNAs are seen in both the nucleus and the cytoplasm to a similar degree, but of the transcripts that are highly enriched in one compartment, far more are nuclear than cytoplasmic. Interestingly, under oxidative stress conditions, we observed an increase in lncRNA localization in both nuclear and cytoplasmic fractions. In addition, we found that nuclear localization was partially attributable to the presence of previously described nuclear retention motifs, while adenosine to inosine (A-to-I) RNA editing appeared to play a very minimal role. Conclusions Our findings map lncRNA localization in the RPE and provide two avenues for future research: 1) how lncRNAs function in the RPE, and 2) how one environmental factor, in isolation, may potentially play a role in retinal disease pathogenesis through altered lncRNA localization. Supplementary Information The online version contains supplementary material available at 10.1186/s12864-022-08777-1.
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Affiliation(s)
- Tadeusz J Kaczynski
- Department of Ophthalmology, State University of New York at Buffalo, Buffalo, NY, USA.,Research Service, VA Medical Center, Buffalo, NY, USA
| | - Elizabeth D Au
- Department of Ophthalmology, State University of New York at Buffalo, Buffalo, NY, USA
| | - Michael H Farkas
- Department of Ophthalmology, State University of New York at Buffalo, Buffalo, NY, USA. .,Research Service, VA Medical Center, Buffalo, NY, USA. .,Department of Biochemistry, State University of New York at Buffalo, Buffalo, NY, USA.
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Górka S, Kubiak D, Ciesińska M, Niedojadło K, Tyburski J, Niedojadło J. Function of Cajal Bodies in Nuclear RNA Retention in A. thaliana Leaves Subjected to Hypoxia. Int J Mol Sci 2022; 23:ijms23147568. [PMID: 35886915 PMCID: PMC9321658 DOI: 10.3390/ijms23147568] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2022] [Revised: 06/27/2022] [Accepted: 06/28/2022] [Indexed: 11/29/2022] Open
Abstract
Retention of RNA in the nucleus precisely regulates the time and rate of translation and controls transcriptional bursts that can generate profound variability in mRNA levels among identical cells in tissues. In this study, we investigated the function of Cajal bodies (CBs) in RNA retention in A. thaliana leaf nuclei during hypoxia stress was investigated. It was observed that in ncb-1 mutants with a complete absence of CBs, the accumulation of poly(A+) RNA in the leaf nuclei was lower than that in wt under stress. Moreover, unlike in root cells, CBs store less RNA, and RNA retention in the nuclei is much less intense. Our results reveal that the function of CBs in the accumulation of RNA in nuclei under stress depends on the plant organ. Additionally, in ncb-1, retention of introns of mRNA RPB1 (largest subunit of RNA polymerase II) mRNA was observed. However, this isoform is highly accumulated in the nucleus. It thus follows that intron retention in transcripts is more important than CBs for the accumulation of RNA in nuclei. Accumulated mRNAs with introns in the nucleus could escape transcript degradation by NMD (nonsense-mediated mRNA decay). From non-fully spliced mRNAs in ncb-1 nuclei, whose levels increase during hypoxia, introns are removed during reoxygenation. Then, the mRNA is transferred to the cytoplasm, and the RPB1 protein is translated. Despite the accumulation of isoforms in nuclei with retention of introns in reoxygenation, ncb-1 coped much worse with long hypoxia, and manifested faster yellowing and shrinkage of leaves.
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Affiliation(s)
- Sylwia Górka
- Department of Cellular and Molecular Biology, Nicolaus Copernicus University, Lwowska 1, 87-100 Toruń, Poland; (S.G.); (D.K.); (M.C.); (K.N.)
- Centre For Modern Interdisciplinary Technologies, Nicolaus Copernicus University, Wileńska 4, 87-100 Toruń, Poland
| | - Dawid Kubiak
- Department of Cellular and Molecular Biology, Nicolaus Copernicus University, Lwowska 1, 87-100 Toruń, Poland; (S.G.); (D.K.); (M.C.); (K.N.)
- Centre For Modern Interdisciplinary Technologies, Nicolaus Copernicus University, Wileńska 4, 87-100 Toruń, Poland
| | - Małgorzata Ciesińska
- Department of Cellular and Molecular Biology, Nicolaus Copernicus University, Lwowska 1, 87-100 Toruń, Poland; (S.G.); (D.K.); (M.C.); (K.N.)
| | - Katarzyna Niedojadło
- Department of Cellular and Molecular Biology, Nicolaus Copernicus University, Lwowska 1, 87-100 Toruń, Poland; (S.G.); (D.K.); (M.C.); (K.N.)
- Centre For Modern Interdisciplinary Technologies, Nicolaus Copernicus University, Wileńska 4, 87-100 Toruń, Poland
| | - Jarosław Tyburski
- Chair of Plant Physiology and Biotechnology, Nicolaus Copernicus University, Lwowska 1, 87-100 Toruń, Poland;
| | - Janusz Niedojadło
- Department of Cellular and Molecular Biology, Nicolaus Copernicus University, Lwowska 1, 87-100 Toruń, Poland; (S.G.); (D.K.); (M.C.); (K.N.)
- Centre For Modern Interdisciplinary Technologies, Nicolaus Copernicus University, Wileńska 4, 87-100 Toruń, Poland
- Correspondence:
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Faber GP, Nadav-Eliyahu S, Shav-Tal Y. Nuclear speckles - a driving force in gene expression. J Cell Sci 2022; 135:275909. [PMID: 35788677 DOI: 10.1242/jcs.259594] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Nuclear speckles are dynamic membraneless bodies located in the cell nucleus. They harbor RNAs and proteins, many of which are splicing factors, that together display complex biophysical properties dictating nuclear speckle formation and maintenance. Although these nuclear bodies were discovered decades ago, only recently has in-depth genomic analysis begun to unravel their essential functions in modulation of gene activity. Major advancements in genomic mapping techniques combined with microscopy approaches have enabled insights into the roles nuclear speckles may play in enhancing gene expression, and how gene positioning to specific nuclear landmarks can regulate gene expression and RNA processing. Some studies have drawn a link between nuclear speckles and disease. Certain maladies either involve nuclear speckles directly or dictate the localization and reorganization of many nuclear speckle factors. This is most striking during viral infection, as viruses alter the entire nuclear architecture and highjack host machinery. As discussed in this Review, nuclear speckles represent a fascinating target of study not only to reveal the links between gene positioning, genome subcompartments and gene activity, but also as a potential target for therapeutics.
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Affiliation(s)
- Gabriel P Faber
- The Mina and Everard Goodman Faculty of Life Sciences , Bar-Ilan University, Ramat Gan 5290002, Israel.,Institute of Nanotechnology , Bar-Ilan University, Ramat Gan 5290002, Israel
| | - Shani Nadav-Eliyahu
- The Mina and Everard Goodman Faculty of Life Sciences , Bar-Ilan University, Ramat Gan 5290002, Israel.,Institute of Nanotechnology , Bar-Ilan University, Ramat Gan 5290002, Israel
| | - Yaron Shav-Tal
- The Mina and Everard Goodman Faculty of Life Sciences , Bar-Ilan University, Ramat Gan 5290002, Israel.,Institute of Nanotechnology , Bar-Ilan University, Ramat Gan 5290002, Israel
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Gao S, Esparza M, Dehghan I, Aksenova V, Zhang K, Batten K, Ferretti MB, Begg BE, Cagatay T, Shay JW, García-Sastre A, Goldsmith EJ, Chen ZJ, Dasso M, Lynch KW, Cobb MH, Fontoura BMA. Nuclear speckle integrity and function require TAO2 kinase. Proc Natl Acad Sci U S A 2022; 119:e2206046119. [PMID: 35704758 PMCID: PMC9231605 DOI: 10.1073/pnas.2206046119] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2022] [Accepted: 05/16/2022] [Indexed: 11/18/2022] Open
Abstract
Nuclear speckles are non-membrane-bound organelles known as storage sites for messenger RNA (mRNA) processing and splicing factors. More recently, nuclear speckles have also been implicated in splicing and export of a subset of mRNAs, including the influenza virus M mRNA that encodes proteins required for viral entry, trafficking, and budding. However, little is known about how nuclear speckles are assembled or regulated. Here, we uncovered a role for the cellular protein kinase TAO2 as a constituent of nuclear speckles and as a factor required for the integrity of these nuclear bodies and for their functions in pre-mRNA splicing and trafficking. We found that a nuclear pool of TAO2 is localized at nuclear speckles and interacts with nuclear speckle factors involved in RNA splicing and nuclear export, including SRSF1 and Aly/Ref. Depletion of TAO2 or inhibition of its kinase activity disrupts nuclear speckle structure, decreasing the levels of several proteins involved in nuclear speckle assembly and splicing, including SC35 and SON. Consequently, splicing and nuclear export of influenza virus M mRNA were severely compromised and caused a disruption in the virus life cycle. In fact, low levels of TAO2 led to a decrease in viral protein levels and inhibited viral replication. Additionally, depletion or inhibition of TAO2 resulted in abnormal expression of a subset of mRNAs with key roles in viral replication and immunity. Together, these findings uncovered a function of TAO2 in nuclear speckle formation and function and revealed host requirements and vulnerabilities for influenza infection.
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Affiliation(s)
- Shengyan Gao
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390
| | - Matthew Esparza
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390
| | - Ishmael Dehghan
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390
- HHMI, University of Texas Southwestern Medical Center, Dallas, TX 75390
| | - Vasilisa Aksenova
- Division of Molecular and Cellular Biology, National Institute of Child Health and Human Development, NIH, Bethesda, MD 20892
| | - Ke Zhang
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390
| | - Kimberly Batten
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390
| | - Max B. Ferretti
- Department of Biochemistry and Biophysics, University of Pennsylvania, Philadelphia, PA 19104
| | - Bridget E. Begg
- Department of Biochemistry and Biophysics, University of Pennsylvania, Philadelphia, PA 19104
| | - Tolga Cagatay
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390
| | - Jerry W. Shay
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390
| | - Adolfo García-Sastre
- Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, NY 10029
- Global Health and Emerging Pathogens Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029
- Division of Infectious Diseases, Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, NY 10029
- The Tisch Cancer Institute, Icahn School of Medicine at Mount Sinai, New York, NY 10029
- Department of Pathology, Molecular and Cell-Based Medicine, Icahn School of Medicine at Mount Sinai, New York, NY 10029
| | - Elizabeth J. Goldsmith
- Department of Biophysics, University of Texas Southwestern Medical Center, Dallas, TX 75390
| | - Zhijian J. Chen
- Department of Molecular Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390
- HHMI, University of Texas Southwestern Medical Center, Dallas, TX 75390
| | - Mary Dasso
- Division of Molecular and Cellular Biology, National Institute of Child Health and Human Development, NIH, Bethesda, MD 20892
| | - Kristen W. Lynch
- Department of Biochemistry and Biophysics, University of Pennsylvania, Philadelphia, PA 19104
| | - Melanie H. Cobb
- Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, TX 75390
| | - Beatriz M. A. Fontoura
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390
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Rudzka M, Wróblewska-Ankiewicz P, Majewska K, Hyjek-Składanowska M, Gołębiewski M, Sikora M, Smoliński DJ, Kołowerzo-Lubnau A. Functional nuclear retention of pre-mRNA involving Cajal bodies during meiotic prophase in European larch (Larix decidua). THE PLANT CELL 2022; 34:2404-2423. [PMID: 35294035 PMCID: PMC9134060 DOI: 10.1093/plcell/koac091] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/19/2021] [Accepted: 03/11/2022] [Indexed: 06/14/2023]
Abstract
Gene regulation ensures that the appropriate genes are expressed at the proper time. Nuclear retention of incompletely spliced or mature mRNAs is emerging as a novel, previously underappreciated layer of posttranscriptional regulation. Studies on this phenomenon indicated that it exerts a significant influence on the regulation of gene expression by regulating export and translation delay, which allows the synthesis of specific proteins in response to a stimulus or at strictly controlled time points, for example, during cell differentiation or development. Here, we show that transcription in microsporocytes of European larch (Larix decidua) occurs in a pulsatile manner during prophase of the first meiotic division. Transcriptional activity was then silenced after each pulse. However, the transcripts synthesized were not exported immediately to the cytoplasm but were retained in the nucleoplasm and Cajal bodies (CBs). In contrast to the nucleoplasm, we did not detect mature transcripts in CBs, which only stored nonfully spliced transcripts with retained introns. Notably, the retained introns were spliced at precisely defined times, and fully mature mRNAs were released into the cytoplasm for translation. As similar processes have been observed during spermatogenesis in animals, our results illustrate an evolutionarily conserved mechanism of gene expression regulation during generative cells development in Eukaryota.
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Affiliation(s)
- Magda Rudzka
- Department of Cellular and Molecular Biology, Nicolaus Copernicus University, Torun 87-100, Poland
- Centre for Modern Interdisciplinary Technologies, Nicolaus Copernicus University, Torun 87-100, Poland
| | - Patrycja Wróblewska-Ankiewicz
- Department of Cellular and Molecular Biology, Nicolaus Copernicus University, Torun 87-100, Poland
- Centre for Modern Interdisciplinary Technologies, Nicolaus Copernicus University, Torun 87-100, Poland
| | - Karolina Majewska
- Department of Cellular and Molecular Biology, Nicolaus Copernicus University, Torun 87-100, Poland
- Centre for Modern Interdisciplinary Technologies, Nicolaus Copernicus University, Torun 87-100, Poland
| | | | - Marcin Gołębiewski
- Centre for Modern Interdisciplinary Technologies, Nicolaus Copernicus University, Torun 87-100, Poland
- Department of Plant Physiology and Biotechnology, Nicolaus Copernicus University, Torun 87-100, Poland
| | - Marcin Sikora
- Centre for Modern Interdisciplinary Technologies, Nicolaus Copernicus University, Torun 87-100, Poland
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Vieira-Vieira CH, Dauksaite V, Sporbert A, Gotthardt M, Selbach M. Proteome-wide quantitative RNA-interactome capture identifies phosphorylation sites with regulatory potential in RBM20. Mol Cell 2022; 82:2069-2083.e8. [DOI: 10.1016/j.molcel.2022.03.024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2021] [Revised: 12/14/2021] [Accepted: 03/18/2022] [Indexed: 10/18/2022]
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Georgiou M, Yang C, Atkinson R, Pan K, Buskin A, Molina MM, Collin J, Al‐Aama J, Goertler F, Ludwig SEJ, Davey T, Lührmann R, Nagaraja‐Grellscheid S, Johnson CA, Ali R, Armstrong L, Korolchuk V, Urlaub H, Mozaffari‐Jovin S, Lako M. Activation of autophagy reverses progressive and deleterious protein aggregation in PRPF31 patient-induced pluripotent stem cell-derived retinal pigment epithelium cells. Clin Transl Med 2022; 12:e759. [PMID: 35297555 PMCID: PMC8926896 DOI: 10.1002/ctm2.759] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2021] [Revised: 02/21/2022] [Accepted: 02/23/2022] [Indexed: 01/18/2023] Open
Abstract
INTRODUCTION Mutations in pre-mRNA processing factor 31 (PRPF31), a core protein of the spliceosomal tri-snRNP complex, cause autosomal-dominant retinitis pigmentosa (adRP). It has remained an enigma why mutations in ubiquitously expressed tri-snRNP proteins result in retina-specific disorders, and so far, the underlying mechanism of splicing factors-related RP is poorly understood. METHODS We used the induced pluripotent stem cell (iPSC) technology to generate retinal organoids and RPE models from four patients with severe and very severe PRPF31-adRP, unaffected individuals and a CRISPR/Cas9 isogenic control. RESULTS To fully assess the impacts of PRPF31 mutations, quantitative proteomics analyses of retinal organoids and RPE cells were carried out showing RNA splicing, autophagy and lysosome, unfolded protein response (UPR) and visual cycle-related pathways to be significantly affected. Strikingly, the patient-derived RPE and retinal cells were characterised by the presence of large amounts of cytoplasmic aggregates containing the mutant PRPF31 and misfolded, ubiquitin-conjugated proteins including key visual cycle and other RP-linked tri-snRNP proteins, which accumulated progressively with time. The mutant PRPF31 variant was not incorporated into splicing complexes, but reduction of PRPF31 wild-type levels led to tri-snRNP assembly defects in Cajal bodies of PRPF31 patient retinal cells, altered morphology of nuclear speckles and reduced formation of active spliceosomes giving rise to global splicing dysregulation. Moreover, the impaired waste disposal mechanisms further exacerbated aggregate formation, and targeting these by activating the autophagy pathway using Rapamycin reduced cytoplasmic aggregates, leading to improved cell survival. CONCLUSIONS Our data demonstrate that it is the progressive aggregate accumulation that overburdens the waste disposal machinery rather than direct PRPF31-initiated mis-splicing, and thus relieving the RPE cells from insoluble cytoplasmic aggregates presents a novel therapeutic strategy that can be combined with gene therapy studies to fully restore RPE and retinal cell function in PRPF31-adRP patients.
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Affiliation(s)
- Maria Georgiou
- Newcastle University Biosciences InstituteNewcastle upon TyneUK
| | - Chunbo Yang
- Newcastle University Biosciences InstituteNewcastle upon TyneUK
| | - Robert Atkinson
- Newcastle University Biosciences InstituteNewcastle upon TyneUK
| | - Kuan‐Ting Pan
- Max Planck Institute for Multidisciplinary SciencesGöttingenGermany
| | - Adriana Buskin
- Newcastle University Biosciences InstituteNewcastle upon TyneUK
| | | | - Joseph Collin
- Newcastle University Biosciences InstituteNewcastle upon TyneUK
| | - Jumana Al‐Aama
- Faculty of MedicineKing Abdulaziz UniversitySaudi Arabia
| | | | | | - Tracey Davey
- Newcastle University Biosciences InstituteNewcastle upon TyneUK
| | | | | | | | | | - Lyle Armstrong
- Newcastle University Biosciences InstituteNewcastle upon TyneUK
| | | | - Henning Urlaub
- Max Planck Institute for Multidisciplinary SciencesGöttingenGermany
- Bioanalytics, Department of Clinical ChemistryUniversity Medical CenterGoettingenGermany
| | - Sina Mozaffari‐Jovin
- Max Planck Institute for Multidisciplinary SciencesGöttingenGermany
- Medical Genetics Research CenterMashhad University of Medical SciencesMashhadIran
- Department of Medical Genetics, Faculty of MedicineMashhad University of Medical SciencesMashhadIran
| | - Majlinda Lako
- Newcastle University Biosciences InstituteNewcastle upon TyneUK
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Alternative Splicing, Epigenetic Modifications and Cancer: A Dangerous Triangle, or a Hopeful One? Cancers (Basel) 2022; 14:cancers14030560. [PMID: 35158828 PMCID: PMC8833605 DOI: 10.3390/cancers14030560] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2021] [Revised: 01/15/2022] [Accepted: 01/18/2022] [Indexed: 12/15/2022] Open
Abstract
Simple Summary Epigenetics studies the alteration of gene expression without changing DNA sequence and very often, epigenetic dysregulation causes cancer. Alternative splicing is a mechanism that results in the production of several mRNA isoforms from a single gene and aberrant splicing is also a frequent cause of cancer. The present review is built on the interrelations of epigenetics and alternative splicing. In an intuitive way, we say that epigenetic modifications and alternative splicing are at two vertices of a triangle, the third vertex being occupied by cancer. Interconnection between alternative splicing and epigenetic modifications occurs backward and forward and the mechanisms involved are widely reviewed. These connections also provide novel diagnostic or prognostic tools, which are listed. Finally, as epigenetic alterations are reversible and aberrant alternative splicing may be corrected, the therapeutic possibilities to break the triangle are discussed. Abstract The alteration of epigenetic modifications often causes cancer onset and development. In a similar way, aberrant alternative splicing may result in oncogenic products. These issues have often been individually reviewed, but there is a growing body of evidence for the interconnection of both causes of cancer. Actually, aberrant splicing may result from abnormal epigenetic signalization and epigenetic factors may be altered by alternative splicing. In this way, the interrelation between epigenetic marks and alternative splicing form the base of a triangle, while cancer may be placed at the vertex. The present review centers on the interconnections at the triangle base, i.e., between alternative splicing and epigenetic modifications, which may result in neoplastic transformations. The effects of different epigenetic factors, including DNA and histone modifications, the binding of non-coding RNAs and the alterations of chromatin organization on alternative splicing resulting in cancer are first considered. Other less-frequently considered questions, such as the epigenetic regulation of the splicing machinery, the aberrant splicing of epigenetic writers, readers and erasers, etc., are next reviewed in their connection with cancer. The knowledge of the above-mentioned relationships has allowed increasing the collection of biomarkers potentially useful as cancer diagnostic and/or prognostic tools. Finally, taking into account on one hand that epigenetic changes are reversible, and some epigenetic drugs already exist and, on the other hand, that drugs intended for reversing aberrations in alternative splicing, therapeutic possibilities for breaking the mentioned cancer-related triangle are discussed.
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Osborne MJ, Volpon L, Memarpooryazdi M, Pillay S, Thambipillai A, Czarnota S, Culjkovic-Kraljacic B, Trahan C, Oeffinger M, Cowling VH, L B Borden K. Identification and characterization of the interaction between the methyl-7-guanosine cap maturation enzyme RNMT and the cap-binding protein eIF4E. J Mol Biol 2022; 434:167451. [PMID: 35026230 DOI: 10.1016/j.jmb.2022.167451] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Revised: 01/04/2022] [Accepted: 01/05/2022] [Indexed: 12/20/2022]
Abstract
The control of RNA metabolism is an important aspect of molecular biology with wide-ranging impacts on cells. Central to processing of coding RNAs is the addition of the methyl-7 guanosine (m7G) "cap" on their 5' end. The eukaryotic translation initiation factor eIF4E directly binds the m7G cap and through this interaction plays key roles in many steps of RNA metabolism including nuclear RNA export and translation. eIF4E also stimulates capping of many transcripts through its ability to drive the production of the enzyme RNMT which methylates the G-cap to form the mature m7G cap. Here, we found that eIF4E also physically associated with RNMT in human cells. Moreover, eIF4E directly interacted with RNMT in vitro. eIF4E is only the second protein reported to directly bind the methyltransferase domain of RNMT, the first being its co-factor RAM. We combined high-resolution NMR methods with biochemical studies to define the binding interfaces for the RNMT-eIF4E complex. Further, we found that eIF4E competes for RAM binding to RNMT and conversely, RNMT competes for binding of well-established eIF4E-binding partners such as the 4E-BPs. RNMT uses novel structural means to engage eIF4E. Finally, we observed that m7G cap-eIF4E-RNMT trimeric complexes form, and thus RNMT-eIF4E complexes may be employed so that eIF4E captures newly capped RNA. In all, we show for the first time that the cap-binding protein eIF4E directly binds to the cap-maturation enzyme RNMT.
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Affiliation(s)
- Michael J Osborne
- Institute of Research in Immunology and Cancer, Department of Pathology and Cell Biology, Université de Montréal, Pavilion Marcelle-Coutu, Chemin Polytechnique, Montréal, QC H3T 1J4, Canada
| | - Laurent Volpon
- Institute of Research in Immunology and Cancer, Department of Pathology and Cell Biology, Université de Montréal, Pavilion Marcelle-Coutu, Chemin Polytechnique, Montréal, QC H3T 1J4, Canada
| | - Mina Memarpooryazdi
- Institute of Research in Immunology and Cancer, Department of Pathology and Cell Biology, Université de Montréal, Pavilion Marcelle-Coutu, Chemin Polytechnique, Montréal, QC H3T 1J4, Canada
| | - Subhadra Pillay
- Institute of Research in Immunology and Cancer, Department of Pathology and Cell Biology, Université de Montréal, Pavilion Marcelle-Coutu, Chemin Polytechnique, Montréal, QC H3T 1J4, Canada; Department of Biological Chemistry, Michigan Medicine, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Aksharh Thambipillai
- Institute of Research in Immunology and Cancer, Department of Pathology and Cell Biology, Université de Montréal, Pavilion Marcelle-Coutu, Chemin Polytechnique, Montréal, QC H3T 1J4, Canada
| | - Sylwia Czarnota
- Institute of Research in Immunology and Cancer, Department of Pathology and Cell Biology, Université de Montréal, Pavilion Marcelle-Coutu, Chemin Polytechnique, Montréal, QC H3T 1J4, Canada
| | - Biljana Culjkovic-Kraljacic
- Institute of Research in Immunology and Cancer, Department of Pathology and Cell Biology, Université de Montréal, Pavilion Marcelle-Coutu, Chemin Polytechnique, Montréal, QC H3T 1J4, Canada
| | - Christian Trahan
- Department for Systems Biology, Institut de Recherches Cliniques de Montréal, Montréal, QC H2W 1R7, Canada; Département de Biochimie et Médecine Moléculaire, Université de Montréal, Montréal, QC H3T 1J4, Canada
| | - Marlene Oeffinger
- Department for Systems Biology, Institut de Recherches Cliniques de Montréal, Montréal, QC H2W 1R7, Canada; Département de Biochimie et Médecine Moléculaire, Université de Montréal, Montréal, QC H3T 1J4, Canada; Division of Experimental Medicine, McGill University, Montréal, QC, Canada
| | - Victoria H Cowling
- Centre for Gene Regulation and Expression, School of Life Sciences, University of Dundee, Dundee, UK, DD1 5EH
| | - Katherine L B Borden
- Institute of Research in Immunology and Cancer, Department of Pathology and Cell Biology, Université de Montréal, Pavilion Marcelle-Coutu, Chemin Polytechnique, Montréal, QC H3T 1J4, Canada.
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Maron MI, Casill AD, Gupta V, Roth JS, Sidoli S, Query CC, Gamble MJ, Shechter D. Type I and II PRMTs inversely regulate post-transcriptional intron detention through Sm and CHTOP methylation. eLife 2022; 11:e72867. [PMID: 34984976 PMCID: PMC8765754 DOI: 10.7554/elife.72867] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Accepted: 01/03/2022] [Indexed: 12/26/2022] Open
Abstract
Protein arginine methyltransferases (PRMTs) are required for the regulation of RNA processing factors. Type I PRMT enzymes catalyze mono- and asymmetric dimethylation; Type II enzymes catalyze mono- and symmetric dimethylation. To understand the specific mechanisms of PRMT activity in splicing regulation, we inhibited Type I and II PRMTs and probed their transcriptomic consequences. Using the newly developed Splicing Kinetics and Transcript Elongation Rates by Sequencing (SKaTER-seq) method, analysis of co-transcriptional splicing demonstrated that PRMT inhibition resulted in altered splicing rates. Surprisingly, co-transcriptional splicing kinetics did not correlate with final changes in splicing of polyadenylated RNA. This was particularly true for retained introns (RI). By using actinomycin D to inhibit ongoing transcription, we determined that PRMTs post-transcriptionally regulate RI. Subsequent proteomic analysis of both PRMT-inhibited chromatin and chromatin-associated polyadenylated RNA identified altered binding of many proteins, including the Type I substrate, CHTOP, and the Type II substrate, SmB. Targeted mutagenesis of all methylarginine sites in SmD3, SmB, and SmD1 recapitulated splicing changes seen with Type II PRMT inhibition, without disrupting snRNP assembly. Similarly, mutagenesis of all methylarginine sites in CHTOP recapitulated the splicing changes seen with Type I PRMT inhibition. Examination of subcellular fractions further revealed that RI were enriched in the nucleoplasm and chromatin. Taken together, these data demonstrate that, through Sm and CHTOP arginine methylation, PRMTs regulate the post-transcriptional processing of nuclear, detained introns.
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Affiliation(s)
- Maxim I Maron
- Department of Biochemistry, Albert Einstein College of MedicineBronxUnited States
| | - Alyssa D Casill
- Department of Molecular Pharmacology, Albert Einstein College of MedicineBronxUnited States
| | - Varun Gupta
- Department of Cell Biology, Albert Einstein College of MedicineBronxUnited States
| | - Jacob S Roth
- Department of Biochemistry, Albert Einstein College of MedicineBronxUnited States
| | - Simone Sidoli
- Department of Biochemistry, Albert Einstein College of MedicineBronxUnited States
| | - Charles C Query
- Department of Cell Biology, Albert Einstein College of MedicineBronxUnited States
| | - Matthew J Gamble
- Department of Molecular Pharmacology, Albert Einstein College of MedicineBronxUnited States
- Department of Cell Biology, Albert Einstein College of MedicineBronxUnited States
| | - David Shechter
- Department of Biochemistry, Albert Einstein College of MedicineBronxUnited States
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42
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Zhang J, Liu W, Li G, Xu C, Nie X, Qin D, Wang Q, Lu X, Liu J, Li L. BCAS2 is involved in alternative splicing and mouse oocyte development. FASEB J 2022; 36:e22128. [PMID: 34972250 DOI: 10.1096/fj.202101279r] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2021] [Revised: 12/06/2021] [Accepted: 12/16/2021] [Indexed: 11/11/2022]
Abstract
Alternative splicing (AS) is an important mechanism to regulate organogenesis and fertility. Breast carcinoma amplified sequence 2 (BCAS2) is one of the core components of the PRP19 complex, a multiple function complex including splicing, and it is involved in the initiation of meiosis through regulating AS in male mice. However, the role of BCAS2 in mouse oogenesis remains largely unknown. In this study, we found that BCAS2 was highly expressed in the oocytes of primordial follicles. Vasa-Cre-mediated deletion of Bcas2 caused poor oocyte quality, abnormal oogenesis and follicular development. The deletion of Bcas2 in mouse oocytes caused alteration in 991 AS events that corresponded to 706 genes, including Pabpc1l, Nobox, Zfp207, Mybl2, Prc1, and Spc25, which were associated with oogenesis and spindle assembly. Moreover, the disruption of BCAS2 led to degradation of PRP19 core proteins in mouse oocytes. These results suggested that BCAS2 was involved in the AS of functional genes through PRP19 complex during mouse oocyte development.
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Affiliation(s)
- Jiaqi Zhang
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China.,Chinese Academy of Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Wenbo Liu
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China.,Department of Obstetrics and Gynecology, Center for Reproductive Medicine, Key Laboratory for Major Obstetric Diseases of Guangdong Province, The Third Affiliated Hospital of Guangzhou Medical University, Guangzhou, China.,Key Laboratory for Reproductive Medicine of Guangdong Province, The Third Affiliated Hospital of Guangzhou Medical University, Guangzhou, China
| | - Guangyue Li
- Key Laboratory of Saline-Alkali Vegetation Ecology Restoration, Ministry of Education, College of Life Science, Northeast Forestry University, Harbin, China
| | - Chengpeng Xu
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China.,Chinese Academy of Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Xiaoqing Nie
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China.,Chinese Academy of Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Dandan Qin
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
| | - Qizhi Wang
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China.,Chinese Academy of Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Xukun Lu
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
| | - Jianqiao Liu
- Department of Obstetrics and Gynecology, Center for Reproductive Medicine, Key Laboratory for Major Obstetric Diseases of Guangdong Province, The Third Affiliated Hospital of Guangzhou Medical University, Guangzhou, China.,Key Laboratory for Reproductive Medicine of Guangdong Province, The Third Affiliated Hospital of Guangzhou Medical University, Guangzhou, China
| | - Lei Li
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
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43
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Naro C, De Musso M, Delle Monache F, Panzeri V, de la Grange P, Sette C. The oncogenic kinase NEK2 regulates an RBFOX2-dependent pro-mesenchymal splicing program in triple-negative breast cancer cells. J Exp Clin Cancer Res 2021; 40:397. [PMID: 34930366 PMCID: PMC8686545 DOI: 10.1186/s13046-021-02210-3] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2021] [Accepted: 12/06/2021] [Indexed: 01/05/2023] Open
Abstract
BACKGROUND Triple-negative breast cancer (TNBC) is the most heterogeneous and malignant subtype of breast cancer (BC). TNBC is defined by the absence of expression of estrogen, progesterone and HER2 receptors and lacks efficacious targeted therapies. NEK2 is an oncogenic kinase that is significantly upregulated in TNBC, thereby representing a promising therapeutic target. NEK2 localizes in the nucleus and promotes oncogenic splice variants in different cancer cells. Notably, alternative splicing (AS) dysregulation has recently emerged as a featuring trait of TNBC that contributes to its aggressive phenotype. METHODS To investigate whether NEK2 modulates TNBC transcriptome we performed RNA-sequencing analyses in a representative TNBC cell line (MDA-MB-231) and results were validated in multiple TNBC cell lines. Bioinformatics and functional analyses were carried out to elucidate the mechanism of splicing regulation by NEK2. Data from The Cancer Genome Atlas were mined to evaluate the potential of NEK2-sensitive exons as markers to identify the TNBC subtype and to assess their prognostic value. RESULTS Transcriptome analysis revealed a widespread impact of NEK2 on the transcriptome of TNBC cells, with 1830 AS events that are susceptible to its expression. NEK2 regulates the inclusion of cassette exons in splice variants that discriminate TNBC from other BC and that correlate with poor prognosis, suggesting that this kinase contributes to the TNBC-specific splicing program. NEK2 elicits its effects by modulating the expression of the splicing factor RBFOX2, a well-known regulator of epithelial to mesenchymal transition (EMT). Accordingly, NEK2 splicing-regulated genes are enriched in functional terms related to cell adhesion and contractile cytoskeleton and NEK2 depletion in mesenchymal TNBC cells induces phenotypic and molecular traits typical of epithelial cells. Remarkably, depletion of select NEK2-sensitive splice-variants that are prognostic in TNBC patients is sufficient to interfere with TNBC cell morphology and motility, suggesting that NEK2 orchestrates a pro-mesenchymal splicing program that modulates migratory and invasive properties of TNBC cells. CONCLUSIONS Our study uncovers an extensive splicing program modulated by NEK2 involving splice variants that confer an invasive phenotype to TNBCs and that might represent, together with NEK2 itself, valuable therapeutic targets for this disease.
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Affiliation(s)
- Chiara Naro
- Department of Neuroscience, Section of Human Anatomy, Catholic University of the Sacred Heart, 00168, Rome, Italy.
- Fondazione Policlinico Universitario A. Gemelli, IRCCS, Rome, Italy.
| | - Monica De Musso
- Department of Neuroscience, Section of Human Anatomy, Catholic University of the Sacred Heart, 00168, Rome, Italy
- Fondazione Policlinico Universitario A. Gemelli, IRCCS, Rome, Italy
| | - Francesca Delle Monache
- Department of Neuroscience, Section of Human Anatomy, Catholic University of the Sacred Heart, 00168, Rome, Italy
- Fondazione Policlinico Universitario A. Gemelli, IRCCS, Rome, Italy
| | - Valentina Panzeri
- Department of Neuroscience, Section of Human Anatomy, Catholic University of the Sacred Heart, 00168, Rome, Italy
- Fondazione Policlinico Universitario A. Gemelli, IRCCS, Rome, Italy
| | | | - Claudio Sette
- Department of Neuroscience, Section of Human Anatomy, Catholic University of the Sacred Heart, 00168, Rome, Italy.
- Fondazione Santa Lucia, IRCCS, Rome, Italy.
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44
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Mars JC, Ghram M, Culjkovic-Kraljacic B, Borden KLB. The Cap-Binding Complex CBC and the Eukaryotic Translation Factor eIF4E: Co-Conspirators in Cap-Dependent RNA Maturation and Translation. Cancers (Basel) 2021; 13:6185. [PMID: 34944805 PMCID: PMC8699206 DOI: 10.3390/cancers13246185] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Revised: 11/30/2021] [Accepted: 12/02/2021] [Indexed: 12/26/2022] Open
Abstract
The translation of RNA into protein is a dynamic process which is heavily regulated during normal cell physiology and can be dysregulated in human malignancies. Its dysregulation can impact selected groups of RNAs, modifying protein levels independently of transcription. Integral to their suitability for translation, RNAs undergo a series of maturation steps including the addition of the m7G cap on the 5' end of RNAs, splicing, as well as cleavage and polyadenylation (CPA). Importantly, each of these steps can be coopted to modify the transcript signal. Factors that bind the m7G cap escort these RNAs through different steps of maturation and thus govern the physical nature of the final transcript product presented to the translation machinery. Here, we describe these steps and how the major m7G cap-binding factors in mammalian cells, the cap binding complex (CBC) and the eukaryotic translation initiation factor eIF4E, are positioned to chaperone transcripts through RNA maturation, nuclear export, and translation in a transcript-specific manner. To conceptualize a framework for the flow and integration of this genetic information, we discuss RNA maturation models and how these integrate with translation. Finally, we discuss how these processes can be coopted by cancer cells and means to target these in malignancy.
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Affiliation(s)
- Jean-Clement Mars
- Institute for Research in Immunology and Cancer (IRIC), Université de Montréal, Pavillion Marcelle-Coutu, Chemin Polytechnique, Montreal, QC H3T 1J4, Canada
| | - Mehdi Ghram
- Institute for Research in Immunology and Cancer (IRIC), Université de Montréal, Pavillion Marcelle-Coutu, Chemin Polytechnique, Montreal, QC H3T 1J4, Canada
| | - Biljana Culjkovic-Kraljacic
- Institute for Research in Immunology and Cancer (IRIC), Université de Montréal, Pavillion Marcelle-Coutu, Chemin Polytechnique, Montreal, QC H3T 1J4, Canada
| | - Katherine L B Borden
- Institute for Research in Immunology and Cancer (IRIC), Université de Montréal, Pavillion Marcelle-Coutu, Chemin Polytechnique, Montreal, QC H3T 1J4, Canada
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45
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Rivera C, Verbel-Vergara D, Arancibia D, Lappala A, González M, Guzmán F, Merello G, Lee JT, Andrés ME. Revealing RCOR2 as a regulatory component of nuclear speckles. Epigenetics Chromatin 2021; 14:51. [PMID: 34819154 PMCID: PMC8611983 DOI: 10.1186/s13072-021-00425-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2021] [Accepted: 10/31/2021] [Indexed: 12/26/2022] Open
Abstract
Background Nuclear processes such as transcription and RNA maturation can be impacted by subnuclear compartmentalization in condensates and nuclear bodies. Here, we characterize the nature of nuclear granules formed by REST corepressor 2 (RCOR2), a nuclear protein essential for pluripotency maintenance and central nervous system development. Results Using biochemical approaches and high-resolution microscopy, we reveal that RCOR2 is localized in nuclear speckles across multiple cell types, including neurons in the brain. RCOR2 forms complexes with nuclear speckle components such as SON, SRSF7, and SRRM2. When cells are exposed to chemical stress, RCOR2 behaves as a core component of the nuclear speckle and is stabilized by RNA. In turn, nuclear speckle morphology appears to depend on RCOR2. Specifically, RCOR2 knockdown results larger nuclear speckles, whereas overexpressing RCOR2 leads to smaller and rounder nuclear speckles. Conclusion Our study suggests that RCOR2 is a regulatory component of the nuclear speckle bodies, setting this co-repressor protein as a factor that controls nuclear speckles behavior. Supplementary Information The online version contains supplementary material available at 10.1186/s13072-021-00425-4.
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Affiliation(s)
- Carlos Rivera
- Department of Cellular and Molecular Biology, Faculty of Biological Sciences, Pontificia Universidad Católica de Chile, Avenida Del Libertador Bernardo O'Higgins 340, 8320000, Santiago, Chile.,Department of Molecular Biology, Massachusetts General Hospital, 185 Cambridge Street, CPZN 6624, Boston, MA, 02114, USA.,Department of Genetics, The Blavatnik Institute, Harvard Medical School, Boston, MA, 02114, USA
| | - Daniel Verbel-Vergara
- Department of Cellular and Molecular Biology, Faculty of Biological Sciences, Pontificia Universidad Católica de Chile, Avenida Del Libertador Bernardo O'Higgins 340, 8320000, Santiago, Chile
| | - Duxan Arancibia
- Department of Cellular and Molecular Biology, Faculty of Biological Sciences, Pontificia Universidad Católica de Chile, Avenida Del Libertador Bernardo O'Higgins 340, 8320000, Santiago, Chile
| | - Anna Lappala
- Department of Molecular Biology, Massachusetts General Hospital, 185 Cambridge Street, CPZN 6624, Boston, MA, 02114, USA.,Department of Genetics, The Blavatnik Institute, Harvard Medical School, Boston, MA, 02114, USA
| | - Marcela González
- Department of Cellular and Molecular Biology, Faculty of Biological Sciences, Pontificia Universidad Católica de Chile, Avenida Del Libertador Bernardo O'Higgins 340, 8320000, Santiago, Chile
| | - Fabián Guzmán
- Department of Cellular and Molecular Biology, Faculty of Biological Sciences, Pontificia Universidad Católica de Chile, Avenida Del Libertador Bernardo O'Higgins 340, 8320000, Santiago, Chile
| | - Gianluca Merello
- Department of Cellular and Molecular Biology, Faculty of Biological Sciences, Pontificia Universidad Católica de Chile, Avenida Del Libertador Bernardo O'Higgins 340, 8320000, Santiago, Chile
| | - Jeannie T Lee
- Department of Molecular Biology, Massachusetts General Hospital, 185 Cambridge Street, CPZN 6624, Boston, MA, 02114, USA. .,Department of Genetics, The Blavatnik Institute, Harvard Medical School, Boston, MA, 02114, USA.
| | - María Estela Andrés
- Department of Cellular and Molecular Biology, Faculty of Biological Sciences, Pontificia Universidad Católica de Chile, Avenida Del Libertador Bernardo O'Higgins 340, 8320000, Santiago, Chile.
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46
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Ling Y, Mahfouz MM, Zhou S. Pre-mRNA alternative splicing as a modulator for heat stress response in plants. TRENDS IN PLANT SCIENCE 2021; 26:1153-1170. [PMID: 34334317 DOI: 10.1016/j.tplants.2021.07.008] [Citation(s) in RCA: 49] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Revised: 07/01/2021] [Accepted: 07/07/2021] [Indexed: 05/11/2023]
Abstract
The molecular responses of plants to the important abiotic stress, heat stress (HS), have been extensively studied at the transcriptional level. Alternative splicing (AS) is a post-transcriptional regulatory process in which an intron-containing gene can generate more than one mRNA variant. The impact of HS on the pre-mRNA splicing process has been reported in various eukaryotes but seldom discussed in-depth, especially in plants. Here, we review AS regulation in response to HS in different plant species. We discuss potential molecular mechanisms controlling heat-inducible AS regulation in plants and hypothesize that AS regulation participates in heat-priming establishment and HS memory maintenance. We propose that the pre-mRNA splicing variation is an important regulator of plant HS responses (HSRs).
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Affiliation(s)
- Yu Ling
- College of Coastal Agricultural Sciences, Guangdong Ocean University, Zhanjiang, 524088, PR China; Laboratory for Genome Engineering, Division of Biological Sciences, 4700 King Abdullah University of Science and Technology, Thuwal 23955-6900, Saudi Arabia; South China Branch of National Saline-Alkali Tolerant Rice Technology Innovation Center, Zhanjiang, 524088, PR China.
| | - Magdy M Mahfouz
- Laboratory for Genome Engineering, Division of Biological Sciences, 4700 King Abdullah University of Science and Technology, Thuwal 23955-6900, Saudi Arabia.
| | - Shuangxi Zhou
- New Zealand Institute for Plant and Food Research Limited, Hawke's Bay 4130, New Zealand
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47
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Lu YY, Krebber H. Nuclear mRNA Quality Control and Cytoplasmic NMD Are Linked by the Guard Proteins Gbp2 and Hrb1. Int J Mol Sci 2021; 22:ijms222011275. [PMID: 34681934 PMCID: PMC8541090 DOI: 10.3390/ijms222011275] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Revised: 10/13/2021] [Accepted: 10/17/2021] [Indexed: 12/23/2022] Open
Abstract
Pre-mRNA splicing is critical for cells, as defects in this process can lead to altered open reading frames and defective proteins, potentially causing neurodegenerative diseases and cancer. Introns are removed in the nucleus and splicing is documented by the addition of exon-junction-complexes (EJCs) at exon-exon boundaries. This “memory” of splicing events is important for the ribosome, which translates the RNAs in the cytoplasm. In case a stop codon was detected before an EJC, translation is blocked and the RNA is eliminated by the nonsense-mediated decay (NMD). In the model organism Saccharomyces cerevisiae, two guard proteins, Gbp2 and Hrb1, have been identified as nuclear quality control factors for splicing. In their absence, intron-containing mRNAs leak into the cytoplasm. Their presence retains transcripts until the process is completed and they release the mRNAs by recruitment of the export factor Mex67. On transcripts that experience splicing problems, these guard proteins recruit the nuclear RNA degradation machinery. Interestingly, they continue their quality control function on exported transcripts. They support NMD by inhibiting translation and recruiting the cytoplasmic degradation factors. In this way, they link the nuclear and cytoplasmic quality control systems. These discoveries are also intriguing for humans, as homologues of these guard proteins are present also in multicellular organisms. Here, we provide an overview of the quality control mechanisms of pre-mRNA splicing, and present Gbp2 and Hrb1, as well as their human counterparts, as important players in these pathways.
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48
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Bento FMM, Darolt JC, Merlin BL, Penã L, Wulff NA, Cônsoli FL. The molecular interplay of the establishment of an infection - gene expression of Diaphorina citri gut and Candidatus Liberibacter asiaticus. BMC Genomics 2021; 22:677. [PMID: 34544390 PMCID: PMC8454146 DOI: 10.1186/s12864-021-07988-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Accepted: 09/03/2021] [Indexed: 12/19/2022] Open
Abstract
BACKGROUND Candidatus Liberibacter asiaticus (CLas) is one the causative agents of greening disease in citrus, an unccurable, devastating disease of citrus worldwide. CLas is vectored by Diaphorina citri, and the understanding of the molecular interplay between vector and pathogen will provide additional basis for the development and implementation of successful management strategies. We focused in the molecular interplay occurring in the gut of the vector, a major barrier for CLas invasion and colonization. RESULTS We investigated the differential expression of vector and CLas genes by analyzing a de novo reference metatranscriptome of the gut of adult psyllids fed of CLas-infected and healthy citrus plants for 1-2, 3-4 and 5-6 days. CLas regulates the immune response of the vector affecting the production of reactive species of oxygen and nitrogen, and the production of antimicrobial peptides. Moreover, CLas overexpressed peroxiredoxin, probably in a protective manner. The major transcript involved in immune expression was related to melanization, a CLIP-domain serine protease we believe participates in the wounding of epithelial cells damaged during infection, which is supported by the down-regulation of pangolin. We also detected that CLas modulates the gut peristalsis of psyllids through the down-regulation of titin, reducing the elimination of CLas with faeces. The up-regulation of the neuromodulator arylalkylamine N-acetyltransferase implies CLas also interferes with the double brain-gut communication circuitry of the vector. CLas colonizes the gut by expressing two Type IVb pilin flp genes and several chaperones that can also function as adhesins. We hypothesized biofilm formation occurs by the expression of the cold shock protein of CLas. CONCLUSIONS The thorough detailed analysis of the transcritome of Ca. L. asiaticus and of D. citri at different time points of their interaction in the gut tissues of the host led to the identification of several host genes targeted for regulation by L. asiaticus, but also bacterial genes coding for potential effector proteins. The identified targets and effector proteins are potential targets for the development of new management strategies directed to interfere with the successful utilization of the psyllid vector by this pathogen.
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Affiliation(s)
- Flavia Moura Manoel Bento
- Insect Interactions Laboratory, Department of Entomology and Acarology, Luiz de Queiroz College of Agriculture, University of São Paulo, Avenida Pádua Dias 11, Piracicaba, São Paulo 13418-900 Brazil
| | - Josiane Cecília Darolt
- Fund for Citrus Protection (FUNDECITRUS), Araraquara, São Paulo 14807-040 Brazil
- Institute of Chemistry, São Paulo State University – UNESP, Araraquara, São Paulo Brazil
| | - Bruna Laís Merlin
- Insect Interactions Laboratory, Department of Entomology and Acarology, Luiz de Queiroz College of Agriculture, University of São Paulo, Avenida Pádua Dias 11, Piracicaba, São Paulo 13418-900 Brazil
| | - Leandro Penã
- Fund for Citrus Protection (FUNDECITRUS), Araraquara, São Paulo 14807-040 Brazil
- Instituto de Biología Molecular y Celular de Plantas (IBMCP), Consejo Superior de Investigaciones Científicas (CSIC), Universidad Politécnica de Valencia (UPV), 46022 Valencia, Spain
| | - Nelson Arno Wulff
- Fund for Citrus Protection (FUNDECITRUS), Araraquara, São Paulo 14807-040 Brazil
- Institute of Chemistry, São Paulo State University – UNESP, Araraquara, São Paulo Brazil
| | - Fernando Luis Cônsoli
- Insect Interactions Laboratory, Department of Entomology and Acarology, Luiz de Queiroz College of Agriculture, University of São Paulo, Avenida Pádua Dias 11, Piracicaba, São Paulo 13418-900 Brazil
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49
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Kubina J, Geldreich A, Gales JP, Baumberger N, Bouton C, Ryabova LA, Grasser KD, Keller M, Dimitrova M. Nuclear export of plant pararetrovirus mRNAs involves the TREX complex, two viral proteins and the highly structured 5' leader region. Nucleic Acids Res 2021; 49:8900-8922. [PMID: 34370034 PMCID: PMC8421220 DOI: 10.1093/nar/gkab653] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2020] [Revised: 07/09/2021] [Accepted: 07/22/2021] [Indexed: 11/13/2022] Open
Abstract
In eukaryotes, the major nuclear export pathway for mature mRNAs uses the dimeric receptor TAP/p15, which is recruited to mRNAs via the multisubunit TREX complex, comprising the THO core and different export adaptors. Viruses that replicate in the nucleus adopt different strategies to hijack cellular export factors and achieve cytoplasmic translation of their mRNAs. No export receptors are known in plants, but Arabidopsis TREX resembles the mammalian complex, with a conserved hexameric THO core associated with ALY and UIEF proteins, as well as UAP56 and MOS11. The latter protein is an orthologue of mammalian CIP29. The nuclear export mechanism for viral mRNAs has not been described in plants. To understand this process, we investigated the export of mRNAs of the pararetrovirus CaMV in Arabidopsis and demonstrated that it is inhibited in plants deficient in ALY, MOS11 and/or TEX1. Deficiency for these factors renders plants partially resistant to CaMV infection. Two CaMV proteins, the coat protein P4 and reverse transcriptase P5, are important for nuclear export. P4 and P5 interact and co-localise in the nucleus with the cellular export factor MOS11. The highly structured 5′ leader region of 35S RNAs was identified as an export enhancing element that interacts with ALY1, ALY3 and MOS11 in vitro.
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Affiliation(s)
- Julie Kubina
- Institut de biologie moléculaire des plantes, CNRS, Université de Strasbourg, Strasbourg, France
| | - Angèle Geldreich
- Institut de biologie moléculaire des plantes, CNRS, Université de Strasbourg, Strasbourg, France
| | - Jón Pol Gales
- Institut de biologie moléculaire des plantes, CNRS, Université de Strasbourg, Strasbourg, France
| | - Nicolas Baumberger
- Institut de biologie moléculaire des plantes, CNRS, Université de Strasbourg, Strasbourg, France
| | - Clément Bouton
- Institut de biologie moléculaire des plantes, CNRS, Université de Strasbourg, Strasbourg, France
| | - Lyubov A Ryabova
- Institut de biologie moléculaire des plantes, CNRS, Université de Strasbourg, Strasbourg, France
| | - Klaus D Grasser
- Cell Biology & Plant Biochemistry, Biochemistry Centre, University of Regensburg, D-93053 Regensburg, Germany
| | - Mario Keller
- Institut de biologie moléculaire des plantes, CNRS, Université de Strasbourg, Strasbourg, France
| | - Maria Dimitrova
- Institut de biologie moléculaire des plantes, CNRS, Université de Strasbourg, Strasbourg, France
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Nuclear compartmentalization as a mechanism of quantitative control of gene expression. Nat Rev Mol Cell Biol 2021; 22:653-670. [PMID: 34341548 DOI: 10.1038/s41580-021-00387-1] [Citation(s) in RCA: 123] [Impact Index Per Article: 41.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/28/2021] [Indexed: 01/08/2023]
Abstract
Gene regulation requires the dynamic coordination of hundreds of regulatory factors at precise genomic and RNA targets. Although many regulatory factors have specific affinity for their nucleic acid targets, molecular diffusion and affinity models alone cannot explain many of the quantitative features of gene regulation in the nucleus. One emerging explanation for these quantitative properties is that DNA, RNA and proteins organize within precise, 3D compartments in the nucleus to concentrate groups of functionally related molecules. Recently, nucleic acids and proteins involved in many important nuclear processes have been shown to engage in cooperative interactions, which lead to the formation of condensates that partition the nucleus. In this Review, we discuss an emerging perspective of gene regulation, which moves away from classic models of stoichiometric interactions towards an understanding of how spatial compartmentalization can lead to non-stoichiometric molecular interactions and non-linear regulatory behaviours. We describe key mechanisms of nuclear compartment formation, including emerging roles for non-coding RNAs in facilitating their formation, and discuss the functional role of nuclear compartments in transcription regulation, co-transcriptional and post-transcriptional RNA processing, and higher-order chromatin regulation. More generally, we discuss how compartmentalization may explain important quantitative aspects of gene regulation.
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