1
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Zeng Y, Fair BJ, Zeng H, Krishnamohan A, Hou Y, Hall JM, Ruthenburg AJ, Li YI, Staley JP. Profiling lariat intermediates reveals genetic determinants of early and late co-transcriptional splicing. Mol Cell 2022; 82:4681-4699.e8. [PMID: 36435176 PMCID: PMC10448999 DOI: 10.1016/j.molcel.2022.11.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2021] [Revised: 09/10/2022] [Accepted: 11/02/2022] [Indexed: 11/27/2022]
Abstract
Long introns with short exons in vertebrate genes are thought to require spliceosome assembly across exons (exon definition), rather than introns, thereby requiring transcription of an exon to splice an upstream intron. Here, we developed CoLa-seq (co-transcriptional lariat sequencing) to investigate the timing and determinants of co-transcriptional splicing genome wide. Unexpectedly, 90% of all introns, including long introns, can splice before transcription of a downstream exon, indicating that exon definition is not obligatory for most human introns. Still, splicing timing varies dramatically across introns, and various genetic elements determine this variation. Strong U2AF2 binding to the polypyrimidine tract predicts early splicing, explaining exon definition-independent splicing. Together, our findings question the essentiality of exon definition and reveal features beyond intron and exon length that are determinative for splicing timing.
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Affiliation(s)
- Yi Zeng
- Department of Molecular Genetics and Cell Biology, University of Chicago, Chicago, IL 60637, USA
| | - Benjamin J Fair
- Department of Medicine, University of Chicago, Chicago, IL 60637, USA
| | - Huilin Zeng
- 855 Jefferson Ave. Redwood City, CA 94063, USA
| | - Aiswarya Krishnamohan
- Department of Molecular Genetics and Cell Biology, University of Chicago, Chicago, IL 60637, USA
| | - Yichen Hou
- Department of Molecular Genetics and Cell Biology, University of Chicago, Chicago, IL 60637, USA
| | - Johnathon M Hall
- Department of Molecular Genetics and Cell Biology, University of Chicago, Chicago, IL 60637, USA
| | - Alexander J Ruthenburg
- Department of Molecular Genetics and Cell Biology, University of Chicago, Chicago, IL 60637, USA; Department of Biochemistry & Molecular Biology, University of Chicago, Chicago, IL 60637, USA
| | - Yang I Li
- Department of Medicine, University of Chicago, Chicago, IL 60637, USA; Department of Human Genetics, University of Chicago, Chicago, IL 60637, USA.
| | - Jonathan P Staley
- Department of Molecular Genetics and Cell Biology, University of Chicago, Chicago, IL 60637, USA.
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2
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Genome-wide detection of human variants that disrupt intronic branchpoints. Proc Natl Acad Sci U S A 2022; 119:e2211194119. [PMID: 36306325 PMCID: PMC9636908 DOI: 10.1073/pnas.2211194119] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Pre-messenger RNA splicing is initiated with the recognition of a single-nucleotide intronic branchpoint (BP) within a BP motif by spliceosome elements. Forty-eight rare variants in 43 human genes have been reported to alter splicing and cause disease by disrupting BP. However, until now, no computational approach was available to efficiently detect such variants in massively parallel sequencing data. We established a comprehensive human genome-wide BP database by integrating existing BP data and generating new BP data from RNA sequencing of lariat debranching enzyme DBR1-mutated patients and from machine-learning predictions. We characterized multiple features of BP in major and minor introns and found that BP and BP-2 (two nucleotides upstream of BP) positions exhibit a lower rate of variation in human populations and higher evolutionary conservation than the intronic background, while being comparable to the exonic background. We developed BPHunter as a genome-wide computational approach to systematically and efficiently detect intronic variants that may disrupt BP recognition. BPHunter retrospectively identified 40 of the 48 known pathogenic BP variants, in which we summarized a strategy for prioritizing BP variant candidates. The remaining eight variants all create AG-dinucleotides between the BP and acceptor site, which is the likely reason for missplicing. We demonstrated the practical utility of BPHunter prospectively by using it to identify a novel germline heterozygous BP variant of
STAT2
in a patient with critical COVID-19 pneumonia and a novel somatic intronic 59-nucleotide deletion of
ITPKB
in a lymphoma patient, both of which were validated experimentally. BPHunter is publicly available from
https://hgidsoft.rockefeller.edu/BPHunter
and
https://github.com/casanova-lab/BPHunter
.
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3
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Borao S, Ayté J, Hümmer S. Evolution of the Early Spliceosomal Complex-From Constitutive to Regulated Splicing. Int J Mol Sci 2021; 22:ijms222212444. [PMID: 34830325 PMCID: PMC8624252 DOI: 10.3390/ijms222212444] [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: 10/20/2021] [Revised: 11/15/2021] [Accepted: 11/16/2021] [Indexed: 12/14/2022] Open
Abstract
Pre-mRNA splicing is a major process in the regulated expression of genes in eukaryotes, and alternative splicing is used to generate different proteins from the same coding gene. Splicing is a catalytic process that removes introns and ligates exons to create the RNA sequence that codifies the final protein. While this is achieved in an autocatalytic process in ancestral group II introns in prokaryotes, the spliceosome has evolved during eukaryogenesis to assist in this process and to finally provide the opportunity for intron-specific splicing. In the early stage of splicing, the RNA 5' and 3' splice sites must be brought within proximity to correctly assemble the active spliceosome and perform the excision and ligation reactions. The assembly of this first complex, termed E-complex, is currently the least understood process. We focused in this review on the formation of the E-complex and compared its composition and function in three different organisms. We highlight the common ancestral mechanisms in S. cerevisiae, S. pombe, and mammals and conclude with a unifying model for intron definition in constitutive and regulated co-transcriptional splicing.
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Affiliation(s)
- Sonia Borao
- Oxidative Stress and Cell Cycle Group, Universitat Pompeu Fabra, 08003 Barcelona, Spain;
| | - José Ayté
- Oxidative Stress and Cell Cycle Group, Universitat Pompeu Fabra, 08003 Barcelona, Spain;
- Correspondence: (J.A.); (S.H.)
| | - Stefan Hümmer
- Oxidative Stress and Cell Cycle Group, Universitat Pompeu Fabra, 08003 Barcelona, Spain;
- Translational Molecular Pathology, Vall d’Hebron Research Institute (VHIR), CIBERONC, 08035 Barcelona, Spain
- Correspondence: (J.A.); (S.H.)
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4
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Hümmer S, Borao S, Guerra-Moreno A, Cozzuto L, Hidalgo E, Ayté J. Cross talk between the upstream exon-intron junction and Prp2 facilitates splicing of non-consensus introns. Cell Rep 2021; 37:109893. [PMID: 34706246 DOI: 10.1016/j.celrep.2021.109893] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Revised: 04/27/2021] [Accepted: 10/06/2021] [Indexed: 10/20/2022] Open
Abstract
Splicing of mRNA precursors is essential in the regulation of gene expression. U2AF65 recognizes the poly-pyrimidine tract and helps in the recognition of the branch point. Inactivation of fission yeast U2AF65 (Prp2) blocks splicing of most, but not all, pre-mRNAs, for reasons that are not understood. Here, we have determined genome-wide the splicing efficiency of fission yeast cells as they progress into synchronous meiosis in the presence or absence of functional Prp2. Our data indicate that in addition to the splicing elements at the 3' end of any intron, the nucleotides immediately upstream the intron will determine whether Prp2 is required or dispensable for splicing. By changing those nucleotides in any given intron, we regulate its Prp2 dependency. Our results suggest a model in which Prp2 is required for the coordinated recognition of both intronic ends, placing Prp2 as a key regulatory element in the determination of the exon-intron boundaries.
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Affiliation(s)
- Stefan Hümmer
- Oxidative Stress and Cell Cycle Group, Universitat Pompeu Fabra, 08003 Barcelona, Spain.
| | - Sonia Borao
- Oxidative Stress and Cell Cycle Group, Universitat Pompeu Fabra, 08003 Barcelona, Spain
| | - Angel Guerra-Moreno
- Oxidative Stress and Cell Cycle Group, Universitat Pompeu Fabra, 08003 Barcelona, Spain
| | - Luca Cozzuto
- CRG Bioinformatics Core, Centre de Regulació Genòmica (CRG), 08003 Barcelona, Spain
| | - Elena Hidalgo
- Oxidative Stress and Cell Cycle Group, Universitat Pompeu Fabra, 08003 Barcelona, Spain
| | - José Ayté
- Oxidative Stress and Cell Cycle Group, Universitat Pompeu Fabra, 08003 Barcelona, Spain.
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5
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RIPiT-Seq: A tandem immunoprecipitation approach to reveal global binding landscape of multisubunit ribonucleoproteins. Methods Enzymol 2021; 655:401-425. [PMID: 34183131 DOI: 10.1016/bs.mie.2021.03.019] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
RNA-binding proteins (RBPs) regulate all aspects of RNA metabolism. The ability to identify RNA targets bound by RBPs is critical for understanding RBP function. While powerful techniques are available to identify binding sites of individual RBPs at high resolution, it remains challenging to unravel binding sites of multicomponent ribonucleoproteins (RNPs) where multiple RBPs or proteins function cooperatively to bind to target RNAs. To fill this gap, we have previously developed RNA Immunoprecipitation in Tandem followed by high-throughput sequencing (RIPiT-seq) to characterize RNA targets of compositionally distinct RNP complexes by sequentially immunoprecipitating two proteins from the same RNP and sequencing the co-purifying RNA footprints. Here, we provide an updated and improved protocol for RIPiT-seq. In this protocol, we have used CRISPR-Cas9 to introduce affinity tag to endogenous protein of interest to capture a more representative state of an RNP complex. We present a modified protocol for library preparation for high-throughput sequencing so that it exclusively uses equipment and reagents available in a standard molecular biology lab. This updated custom library preparation protocol is compatible with commercial PCR multiplexing systems for Illumina sequencing platform for simultaneous and cost-effective analysis of large number of samples.
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6
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Wan Y, Anastasakis DG, Rodriguez J, Palangat M, Gudla P, Zaki G, Tandon M, Pegoraro G, Chow CC, Hafner M, Larson DR. Dynamic imaging of nascent RNA reveals general principles of transcription dynamics and stochastic splice site selection. Cell 2021; 184:2878-2895.e20. [PMID: 33979654 DOI: 10.1016/j.cell.2021.04.012] [Citation(s) in RCA: 62] [Impact Index Per Article: 20.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2019] [Revised: 11/12/2020] [Accepted: 04/08/2021] [Indexed: 01/06/2023]
Abstract
The activities of RNA polymerase and the spliceosome are responsible for the heterogeneity in the abundance and isoform composition of mRNA in human cells. However, the dynamics of these megadalton enzymatic complexes working in concert on endogenous genes have not been described. Here, we establish a quasi-genome-scale platform for observing synthesis and processing kinetics of single nascent RNA molecules in real time. We find that all observed genes show transcriptional bursting. We also observe large kinetic variation in intron removal for single introns in single cells, which is inconsistent with deterministic splice site selection. Transcriptome-wide footprinting of the U2AF complex, nascent RNA profiling, long-read sequencing, and lariat sequencing further reveal widespread stochastic recursive splicing within introns. We propose and validate a unified theoretical model to explain the general features of transcription and pervasive stochastic splice site selection.
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Affiliation(s)
- Yihan Wan
- Center for Cancer Research, National Cancer Institute, Bethesda, MD 20892, USA
| | - Dimitrios G Anastasakis
- National Institute of Arthritis and Musculoskeletal and Skin Diseases, Bethesda, MD 20892, USA
| | | | - Murali Palangat
- Center for Cancer Research, National Cancer Institute, Bethesda, MD 20892, USA
| | - Prabhakar Gudla
- Center for Cancer Research, National Cancer Institute, Bethesda, MD 20892, USA
| | - George Zaki
- Biomedical Informatics and Data Science Directorate, Frederick National Laboratory for Cancer Research, Frederick, MD, USA
| | - Mayank Tandon
- Center for Cancer Research, National Cancer Institute, Bethesda, MD 20892, USA; Advanced Biomedical Computational Science, Frederick National Laboratory for Cancer Research, Frederick, MD, USA
| | - Gianluca Pegoraro
- Center for Cancer Research, National Cancer Institute, Bethesda, MD 20892, USA
| | - Carson C Chow
- Laboratory of Biological Modeling, NIDDK, Bethesda, MD, USA
| | - Markus Hafner
- National Institute of Arthritis and Musculoskeletal and Skin Diseases, Bethesda, MD 20892, USA.
| | - Daniel R Larson
- Center for Cancer Research, National Cancer Institute, Bethesda, MD 20892, USA.
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7
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Strittmatter LM, Capitanchik C, Newman AJ, Hallegger M, Norman CM, Fica SM, Oubridge C, Luscombe NM, Ule J, Nagai K. psiCLIP reveals dynamic RNA binding by DEAH-box helicases before and after exon ligation. Nat Commun 2021; 12:1488. [PMID: 33674615 PMCID: PMC7935899 DOI: 10.1038/s41467-021-21745-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2020] [Accepted: 02/05/2021] [Indexed: 11/09/2022] Open
Abstract
RNA helicases remodel the spliceosome to enable pre-mRNA splicing, but their binding and mechanism of action remain poorly understood. To define helicase-RNA contacts in specific spliceosomal states, we develop purified spliceosome iCLIP (psiCLIP), which reveals dynamic helicase-RNA contacts during splicing catalysis. The helicase Prp16 binds along the entire available single-stranded RNA region between the branchpoint and 3'-splice site, while Prp22 binds diffusely downstream of the branchpoint before exon ligation, but then switches to more narrow binding in the downstream exon after exon ligation, arguing against a mechanism of processive translocation. Depletion of the exon-ligation factor Prp18 destabilizes Prp22 binding to the pre-mRNA, suggesting that proofreading by Prp22 may sense the stability of the spliceosome during exon ligation. Thus, psiCLIP complements structural studies by providing key insights into the binding and proofreading activity of spliceosomal RNA helicases.
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Affiliation(s)
| | | | | | - Martina Hallegger
- The Francis Crick Institute, London, UK
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, Queen Square, London, UK
| | | | | | | | - Nicholas M Luscombe
- The Francis Crick Institute, London, UK
- UCL Genetics Institute, Department of Genetics, Environment and Evolution, University College London, London, UK
- Okinawa Institute of Science & Technology Graduate University, Okinawa, Japan
| | - Jernej Ule
- The Francis Crick Institute, London, UK.
- Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, Queen Square, London, UK.
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8
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Saldi T, Riemondy K, Erickson B, Bentley DL. Alternative RNA structures formed during transcription depend on elongation rate and modify RNA processing. Mol Cell 2021; 81:1789-1801.e5. [PMID: 33631106 DOI: 10.1016/j.molcel.2021.01.040] [Citation(s) in RCA: 44] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Revised: 01/26/2021] [Accepted: 01/27/2021] [Indexed: 12/24/2022]
Abstract
Most RNA processing occurs co-transcriptionally. We interrogated nascent pol II transcripts by chemical and enzymatic probing and determined how the "nascent RNA structureome" relates to splicing, A-I editing and transcription speed. RNA folding within introns and steep structural transitions at splice sites are associated with efficient co-transcriptional splicing. A slow pol II mutant elicits extensive remodeling into more folded conformations with increased A-I editing. Introns that become more structured at their 3' splice sites get co-transcriptionally excised more efficiently. Slow pol II altered folding of intronic Alu elements where cryptic splicing and intron retention are stimulated, an outcome mimicked by UV, which decelerates transcription. Slow transcription also remodeled RNA folding around alternative exons in distinct ways that predict whether skipping or inclusion is favored, even though it occurs post-transcriptionally. Hence, co-transcriptional RNA folding modulates post-transcriptional alternative splicing. In summary, the plasticity of nascent transcripts has widespread effects on RNA processing.
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Affiliation(s)
- Tassa Saldi
- RNA Bioscience Initiative, Department Biochemistry and Molecular Genetics, University of Colorado School of Medicine, PO Box 6511, Aurora, CO 80045, USA
| | - Kent Riemondy
- RNA Bioscience Initiative, Department Biochemistry and Molecular Genetics, University of Colorado School of Medicine, PO Box 6511, Aurora, CO 80045, USA
| | - Benjamin Erickson
- RNA Bioscience Initiative, Department Biochemistry and Molecular Genetics, University of Colorado School of Medicine, PO Box 6511, Aurora, CO 80045, USA
| | - David L Bentley
- RNA Bioscience Initiative, Department Biochemistry and Molecular Genetics, University of Colorado School of Medicine, PO Box 6511, Aurora, CO 80045, USA.
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9
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Reimer KA, Mimoso CA, Adelman K, Neugebauer KM. Co-transcriptional splicing regulates 3' end cleavage during mammalian erythropoiesis. Mol Cell 2021; 81:998-1012.e7. [PMID: 33440169 DOI: 10.1016/j.molcel.2020.12.018] [Citation(s) in RCA: 89] [Impact Index Per Article: 29.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Revised: 12/07/2020] [Accepted: 12/10/2020] [Indexed: 12/11/2022]
Abstract
Pre-mRNA processing steps are tightly coordinated with transcription in many organisms. To determine how co-transcriptional splicing is integrated with transcription elongation and 3' end formation in mammalian cells, we performed long-read sequencing of individual nascent RNAs and precision run-on sequencing (PRO-seq) during mouse erythropoiesis. Splicing was not accompanied by transcriptional pausing and was detected when RNA polymerase II (Pol II) was within 75-300 nucleotides of 3' splice sites (3'SSs), often during transcription of the downstream exon. Interestingly, several hundred introns displayed abundant splicing intermediates, suggesting that splicing delays can take place between the two catalytic steps. Overall, splicing efficiencies were correlated among introns within the same transcript, and intron retention was associated with inefficient 3' end cleavage. Remarkably, a thalassemia patient-derived mutation introducing a cryptic 3'SS improved both splicing and 3' end cleavage of individual β-globin transcripts, demonstrating functional coupling between the two co-transcriptional processes as a determinant of productive gene output.
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Affiliation(s)
- Kirsten A Reimer
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520, USA
| | - Claudia A Mimoso
- Department of Biological Chemistry and Molecular Pharmacology, Blavatnik Institute, Harvard Medical School, Boston, MA 02115, USA
| | - Karen Adelman
- Department of Biological Chemistry and Molecular Pharmacology, Blavatnik Institute, Harvard Medical School, Boston, MA 02115, USA
| | - Karla M Neugebauer
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520, USA.
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10
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Jia J, Long Y, Zhang H, Li Z, Liu Z, Zhao Y, Lu D, Jin X, Deng X, Xia R, Cao X, Zhai J. Post-transcriptional splicing of nascent RNA contributes to widespread intron retention in plants. NATURE PLANTS 2020; 6:780-788. [PMID: 32541953 DOI: 10.1038/s41477-020-0688-1] [Citation(s) in RCA: 66] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/02/2019] [Accepted: 05/08/2020] [Indexed: 05/21/2023]
Abstract
In eukaryotes, genes are transcribed by RNA polymerase-II (Pol-II) and introns are removed by the spliceosome largely cotranscriptionally1-3; analysis using long-read sequencing revealed that splicing occurs immediately after Pol-II passes introns in yeast4,5. Here, we developed a Nanopore-based method to profile chromatin-bound RNA that enables the simultaneous detection of splicing status, Pol-II position and polyadenylation at the genome-wide scale in Arabidopsis. We found that more than half of the introns remain unspliced after Pol-II transcribes 1 kb past the 3' splice site, which is much slower than the rate of splicing reported in yeast4,5. Many of the full-length chromatin-bound RNA molecules are polyadenylated, yet still contain unspliced introns at specific positions. These introns are nearly absent in the cytoplasm and are resistant to nonsense-mediated decay, suggesting that they are post-transcriptionally spliced before the transcripts are released into the cytoplasm; we therefore termed these introns post-transcriptionally spliced introns (pts introns). Analysis of around 6,500 public RNA-sequencing libraries found that the splicing of pts introns requires the function of splicing-related proteins such as PRMT5 and SKIP, and is also influenced by various environmental signals. The majority of the intron retention events in Arabidopsis are at pts introns, suggesting that chromatin-tethered post-transcriptional splicing is a major contributor to the widespread intron retention that is observed in plants, and could be a mechanism to produce fully spliced functional mRNAs for rapid response.
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Affiliation(s)
- Jinbu Jia
- Institute of Plant and Food Science, Department of Biology, Southern University of Science and Technology, Shenzhen, China
- College of Horticulture, South China Agricultural University, Guangzhou, China
| | - Yanping Long
- Institute of Plant and Food Science, Department of Biology, Southern University of Science and Technology, Shenzhen, China
- Institute for Advanced Studies and College of Life Science, Wuhan University, Wuhan, China
| | - Hong Zhang
- Institute of Plant and Food Science, Department of Biology, Southern University of Science and Technology, Shenzhen, China
| | - Zhuowen Li
- Institute of Plant and Food Science, Department of Biology, Southern University of Science and Technology, Shenzhen, China
| | - Zhijian Liu
- Institute of Plant and Food Science, Department of Biology, Southern University of Science and Technology, Shenzhen, China
| | - Yan Zhao
- Institute of Plant and Food Science, Department of Biology, Southern University of Science and Technology, Shenzhen, China
| | - Dongdong Lu
- Institute of Plant and Food Science, Department of Biology, Southern University of Science and Technology, Shenzhen, China
| | - Xianhao Jin
- Institute of Plant and Food Science, Department of Biology, Southern University of Science and Technology, Shenzhen, China
| | - Xian Deng
- State Key Laboratory of Plant Genomics and National Center for Plant Gene Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
| | - Rui Xia
- College of Horticulture, South China Agricultural University, Guangzhou, China
| | - Xiaofeng Cao
- State Key Laboratory of Plant Genomics and National Center for Plant Gene Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
- Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Beijing, China
| | - Jixian Zhai
- Institute of Plant and Food Science, Department of Biology, Southern University of Science and Technology, Shenzhen, China.
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11
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Liu S, Li B, Liang Q, Liu A, Qu L, Yang J. Classification and function of RNA-protein interactions. WILEY INTERDISCIPLINARY REVIEWS-RNA 2020; 11:e1601. [PMID: 32488992 DOI: 10.1002/wrna.1601] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2019] [Revised: 04/15/2020] [Accepted: 04/29/2020] [Indexed: 12/11/2022]
Abstract
Almost all RNAs need to interact with proteins to fully exert their functions, and proteins also bind to RNAs to act as regulators. It has now become clear that RNA-protein interactions play important roles in many biological processes among organisms. Despite the great progress that has been made in the field, there is still no precise classification system for RNA-protein interactions, which makes it challenging to further decipher the functions and mechanisms of these interactions. In this review, we propose four different categories of RNA-protein interactions according to their basic characteristics: RNA motif-dependent RNA-protein interactions, RNA structure-dependent RNA-protein interactions, RNA modification-dependent RNA-protein interactions, and RNA guide-based RNA-protein interactions. Moreover, the integration of different types of RNA-protein interactions and the regulatory factors implicated in these interactions are discussed. Furthermore, we emphasize the functional diversity of these four types of interactions in biological processes and disease development and assess emerging trends in this exciting research field. This article is categorized under: RNA Interactions with Proteins and Other Molecules > Protein-RNA Interactions: Functional Implications RNA Interactions with Proteins and Other Molecules > Protein-RNA Recognition RNA Processing > RNA Editing and Modification.
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Affiliation(s)
- Shurong Liu
- MOE Key Laboratory of Gene Function and Regulation, State Key Laboratory for Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Bin Li
- MOE Key Laboratory of Gene Function and Regulation, State Key Laboratory for Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Qiaoxia Liang
- MOE Key Laboratory of Gene Function and Regulation, State Key Laboratory for Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Anrui Liu
- MOE Key Laboratory of Gene Function and Regulation, State Key Laboratory for Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Lianghu Qu
- MOE Key Laboratory of Gene Function and Regulation, State Key Laboratory for Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Jianhua Yang
- MOE Key Laboratory of Gene Function and Regulation, State Key Laboratory for Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, China.,Department of Interventional Medicine, The Fifth Affiliated Hospital, Sun Yat-sen University, Zhuhai, China
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12
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Ye X, Jankowsky E. High throughput approaches to study RNA-protein interactions in vitro. Methods 2020; 178:3-10. [PMID: 31494245 PMCID: PMC7071787 DOI: 10.1016/j.ymeth.2019.09.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2019] [Revised: 06/07/2019] [Accepted: 09/01/2019] [Indexed: 02/08/2023] Open
Abstract
To understand the regulation of gene expression it is critical to determine how proteins interact with and discriminate between different RNAs. In this review, we discuss experimental techniques that utilize high throughput approaches to characterize the interactions of proteins with large numbers of RNAs in vitro. We describe the underlying principles for the main methods, briefly discuss their scope and limitations, and outline how insight from the techniques contributes to our understanding of specificity for RNA-protein interactions.
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Affiliation(s)
- Xuan Ye
- Center for RNA Science and Therapeutics, School of Medicine, Case Western Reserve University, Cleveland, OH, United States
| | - Eckhard Jankowsky
- Center for RNA Science and Therapeutics, School of Medicine, Case Western Reserve University, Cleveland, OH, United States.
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13
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Drexler HL, Choquet K, Churchman LS. Splicing Kinetics and Coordination Revealed by Direct Nascent RNA Sequencing through Nanopores. Mol Cell 2020; 77:985-998.e8. [PMID: 31839405 PMCID: PMC7060811 DOI: 10.1016/j.molcel.2019.11.017] [Citation(s) in RCA: 115] [Impact Index Per Article: 28.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Revised: 09/17/2019] [Accepted: 11/18/2019] [Indexed: 02/06/2023]
Abstract
Understanding how splicing events are coordinated across numerous introns in metazoan RNA transcripts requires quantitative analyses of transient RNA processing events in living cells. We developed nanopore analysis of co-transcriptional processing (nano-COP), in which nascent RNAs are directly sequenced through nanopores, exposing the dynamics and patterns of RNA splicing without biases introduced by amplification. Long nano-COP reads reveal that, in human and Drosophila cells, splicing occurs after RNA polymerase II transcribes several kilobases of pre-mRNA, suggesting that metazoan splicing transpires distally from the transcription machinery. Inhibition of the branch-site recognition complex SF3B rapidly diminished global co-transcriptional splicing. We found that splicing order does not strictly follow the order of transcription and is associated with cis-acting elements, alternative splicing, and RNA-binding factors. Further, neighboring introns in human cells tend to be spliced concurrently, implying that splicing of these introns occurs cooperatively. Thus, nano-COP unveils the organizational complexity of RNA processing.
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Affiliation(s)
- Heather L Drexler
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, MA 02115, USA
| | - Karine Choquet
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, MA 02115, USA
| | - L Stirling Churchman
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, MA 02115, USA.
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14
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Abstract
High-throughput sequencing-based methods and their applications in the study of transcriptomes have revolutionized our understanding of alternative splicing. Networks of functionally coordinated and biologically important alternative splicing events continue to be discovered in an ever-increasing diversity of cell types in the context of physiologically normal and disease states. These studies have been complemented by efforts directed at defining sequence codes governing splicing and their cognate trans-acting factors, which have illuminated important combinatorial principles of regulation. Additional studies have revealed critical roles of position-dependent, multivalent protein-RNA interactions that direct splicing outcomes. Investigations of evolutionary changes in RNA binding proteins, splice variants, and associated cis elements have further shed light on the emergence, mechanisms, and functions of splicing networks. Progress in these areas has emphasized the need for a coordinated, community-based effort to systematically address the functions of individual splice variants associated with normal and disease biology.
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15
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Briese M, Haberman N, Sibley CR, Faraway R, Elser AS, Chakrabarti AM, Wang Z, König J, Perera D, Wickramasinghe VO, Venkitaraman AR, Luscombe NM, Saieva L, Pellizzoni L, Smith CWJ, Curk T, Ule J. A systems view of spliceosomal assembly and branchpoints with iCLIP. Nat Struct Mol Biol 2019; 26:930-940. [PMID: 31570875 PMCID: PMC6859068 DOI: 10.1038/s41594-019-0300-4] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2018] [Accepted: 08/14/2019] [Indexed: 02/02/2023]
Abstract
Studies of spliceosomal interactions are challenging due to their dynamic nature. Here we used spliceosome iCLIP, which immunoprecipitates SmB along with small nuclear ribonucleoprotein particles and auxiliary RNA binding proteins, to map spliceosome engagement with pre-messenger RNAs in human cell lines. This revealed seven peaks of spliceosomal crosslinking around branchpoints (BPs) and splice sites. We identified RNA binding proteins that crosslink to each peak, including known and candidate splicing factors. Moreover, we detected the use of over 40,000 BPs with strong sequence consensus and structural accessibility, which align well to nearby crosslinking peaks. We show how the position and strength of BPs affect the crosslinking patterns of spliceosomal factors, which bind more efficiently upstream of strong or proximally located BPs and downstream of weak or distally located BPs. These insights exemplify spliceosome iCLIP as a broadly applicable method for transcriptomic studies of splicing mechanisms.
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Affiliation(s)
- Michael Briese
- MRC Laboratory of Molecular Biology, Cambridge, UK
- Institute of Clinical Neurobiology, University of Wuerzburg, Wuerzburg, Germany
| | - Nejc Haberman
- The Francis Crick Institute, London, UK
- Department of Neuromuscular Disease, UCL Institute of Neurology, London, UK
| | - Christopher R Sibley
- MRC Laboratory of Molecular Biology, Cambridge, UK
- Department of Neuromuscular Disease, UCL Institute of Neurology, London, UK
- Division of Brain Sciences, Department of Medicine, Imperial College London, London, UK
- Institute of Quantitative Biology, Biochemistry and Biotechnology, Edinburgh University, Edinburgh, UK
| | - Rupert Faraway
- The Francis Crick Institute, London, UK
- Department of Neuromuscular Disease, UCL Institute of Neurology, London, UK
| | - Andrea S Elser
- The Francis Crick Institute, London, UK
- Department of Neuromuscular Disease, UCL Institute of Neurology, London, UK
| | - Anob M Chakrabarti
- The Francis Crick Institute, London, UK
- Department of Genetics, Environment and Evolution, UCL Genetics Institute, London, UK
| | - Zhen Wang
- MRC Laboratory of Molecular Biology, Cambridge, UK
| | - Julian König
- MRC Laboratory of Molecular Biology, Cambridge, UK
- Institute of Molecular Biology GmbH, Mainz, Germany
| | - David Perera
- MRC Cancer Unit at the University of Cambridge, Cambridge, UK
| | - Vihandha O Wickramasinghe
- MRC Cancer Unit at the University of Cambridge, Cambridge, UK
- RNA Biology and Cancer Laboratory, Peter MacCallum Cancer Centre, Melbourne, Australia
| | | | - Nicholas M Luscombe
- The Francis Crick Institute, London, UK
- Department of Genetics, Environment and Evolution, UCL Genetics Institute, London, UK
- Okinawa Institute of Science & Technology Graduate University, Okinawa, Japan
| | - Luciano Saieva
- Center for Motor Neuron Biology and Disease, Department of Pathology and Cell Biology, Columbia University, New York, NY, USA
- Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, UK
| | - Livio Pellizzoni
- Center for Motor Neuron Biology and Disease, Department of Pathology and Cell Biology, Columbia University, New York, NY, USA
| | | | - Tomaž Curk
- Faculty of Computer and Information Science, University of Ljubljana, Ljubljana, Slovenia
| | - Jernej Ule
- MRC Laboratory of Molecular Biology, Cambridge, UK.
- The Francis Crick Institute, London, UK.
- Department of Neuromuscular Disease, UCL Institute of Neurology, London, UK.
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16
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RNA Polymerase II Phosphorylated on CTD Serine 5 Interacts with the Spliceosome during Co-transcriptional Splicing. Mol Cell 2019; 72:369-379.e4. [PMID: 30340024 PMCID: PMC6201815 DOI: 10.1016/j.molcel.2018.09.004] [Citation(s) in RCA: 97] [Impact Index Per Article: 19.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2017] [Revised: 07/23/2018] [Accepted: 08/31/2018] [Indexed: 01/22/2023]
Abstract
The highly intronic nature of protein coding genes in mammals necessitates a co-transcriptional splicing mechanism as revealed by mNET-seq analysis. Immunoprecipitation of MNase-digested chromatin with antibodies against RNA polymerase II (Pol II) shows that active spliceosomes (both snRNA and proteins) are complexed to Pol II S5P CTD during elongation and co-transcriptional splicing. Notably, elongating Pol II-spliceosome complexes form strong interactions with nascent transcripts, resulting in footprints of approximately 60 nucleotides. Also, splicing intermediates formed by cleavage at the 5′ splice site are associated with nearly all spliced exons. These spliceosome-bound intermediates are frequently ligated to upstream exons, implying a sequential, constitutive, and U12-dependent splicing process. Finally, lack of detectable spliced products connected to the Pol II active site in human HeLa or murine lymphoid cells suggests that splicing does not occur immediately following 3′ splice site synthesis. Our results imply that most mammalian splicing requires exon definition for completion. S5P CTD Pol II associates with the catalytic spliceosome Elongating Pol II complexes protect about 60 newly synthesized nucleotides Co-transcriptional splicing associated with dominant 5′ ss intermediate U12-dependent introns are sequentially spliced in association with Pol II
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17
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Xu H, Fair BJ, Dwyer ZW, Gildea M, Pleiss JA. Detection of splice isoforms and rare intermediates using multiplexed primer extension sequencing. Nat Methods 2018; 16:55-58. [PMID: 30573814 PMCID: PMC6414223 DOI: 10.1038/s41592-018-0258-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2018] [Accepted: 11/08/2018] [Indexed: 01/05/2023]
Abstract
Targeted RNA-sequencing aims to focus coverage on areas of interest that are inadequately sampled in standard RNA-sequencing experiments. Here we present a novel approach for targeted RNA-sequencing that uses complex pools of reverse transcription primers to enable sequencing enrichment at user-selected locations across the genome. We demonstrate this approach by targeting hundreds to thousands of pre-mRNA splice junctions, revealing high-precision detection of splice isoforms, including rare pre-mRNA splicing intermediates.
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Affiliation(s)
- Hansen Xu
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY, USA
| | - Benjamin J Fair
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY, USA
| | - Zachary W Dwyer
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY, USA
| | - Michael Gildea
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY, USA
| | - Jeffrey A Pleiss
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY, USA.
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18
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Nawy T. Transcripts from a spliceosome. Nat Methods 2018; 15:480. [PMID: 29967507 DOI: 10.1038/s41592-018-0058-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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19
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Furlong R. Scrutinizing spliceosomes. Nat Rev Genet 2018; 19:401. [PMID: 29765162 DOI: 10.1038/s41576-018-0019-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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