1
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Duan C, Mooney T, Buerer L, Bowers C, Rong S, Kim SW, Fredericks AM, Monaghan SF, Fairbrother WG. The unusual gene architecture of polyubiquitin is created by dual-specific splice sites. Genome Biol 2024; 25:33. [PMID: 38268025 PMCID: PMC10809524 DOI: 10.1186/s13059-023-03157-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2023] [Accepted: 12/21/2023] [Indexed: 01/26/2024] Open
Abstract
BACKGROUND The removal of introns occurs through the splicing of a 5' splice site (5'ss) with a 3' splice site (3'ss). These two elements are recognized by distinct components of the spliceosome. However, introns in higher eukaryotes contain many matches to the 5' and 3' splice-site motifs that are presumed not to be used. RESULTS Here, we find that many of these sites can be used. We also find occurrences of the AGGT motif that can function as either a 5'ss or a 3'ss-previously referred to as dual-specific splice sites (DSSs)-within introns. Analysis of the Sequence Read Archive reveals a 3.1-fold enrichment of DSSs relative to expectation, implying synergy between the ability to function as a 5'ss and 3'ss. Despite this suggested mechanistic advantage, DSSs are 2.7- and 4.7-fold underrepresented in annotated 5' and 3' splice sites. A curious exception is the polyubiquitin gene UBC, which contains a tandem array of DSSs that precisely delimit the boundary of each ubiquitin monomer. The resulting isoforms splice stochastically to include a variable number of ubiquitin monomers. We found no evidence of tissue-specific or feedback regulation but note the 8.4-fold enrichment of DSS-spliced introns in tandem repeat genes suggests a driving role in the evolution of genes like UBC. CONCLUSIONS We find an excess of unannotated splice sites and the utilization of DSSs in tandem repeats supports the role of splicing in gene evolution. These findings enhance our understanding of the diverse and complex nature of the splicing process.
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Affiliation(s)
- Chaorui Duan
- Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence, RI, 02903, USA
| | - Truman Mooney
- Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence, RI, 02903, USA
| | - Luke Buerer
- Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence, RI, 02903, USA
| | - Cory Bowers
- Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence, RI, 02903, USA
| | - Stephen Rong
- Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence, RI, 02903, USA
- Center for Computational Molecular Biology, Brown University, Providence, RI, 02903, USA
| | - Seong Won Kim
- Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence, RI, 02903, USA
| | | | - Sean F Monaghan
- Division of Surgical Research, Department of Surgery, Alpert Medical School of Brown University/Rhode Island Hospital, Providence, RI, 02903, USA
| | - William G Fairbrother
- Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence, RI, 02903, USA.
- Center for Computational Molecular Biology, Brown University, Providence, RI, 02903, USA.
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2
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Farberov L, Weissglas-Volkov D, Shapira G, Zoabi Y, Schiff C, Kloeckener-Gruissem B, Neidhardt J, Shomron N. mRNA splicing is modulated by intronic microRNAs. iScience 2023; 26:107723. [PMID: 37692287 PMCID: PMC10492213 DOI: 10.1016/j.isci.2023.107723] [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: 09/15/2022] [Revised: 08/06/2023] [Accepted: 08/22/2023] [Indexed: 09/12/2023] Open
Abstract
Splicing of transcripts is catalyzed by the spliceosome, a mega-complex consisting of hundreds of proteins and five snRNAs, which employs direct interactions. When U1 snRNA forms high-affinity binding, namely more than eight base pairs, with the 5'SS, the result is usually a suppressing effect on the splicing activity. This likely occurs due to the inefficient unwinding of U1/5'SS base-pairing or other regulatory obstructions. Here, we show in vitro and in patient-derived cell lines that pre-microRNAs can modulate the splicing reaction by interacting with U1 snRNA. This leads to reduced binding affinity to the 5'SS, and hence promotes the inclusion of exons containing 5'SS, despite sequence-based high affinity to U1. Application of the mechanism resulted in correction of the splicing defect in the disease-causing VCAN gene from an individual with Wagner syndrome. This pre-miRNA/U1 interaction can regulate the expression of alternatively spliced exons, thus extending the scope of mechanisms regulating splicing.
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Affiliation(s)
- Luba Farberov
- Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Daphna Weissglas-Volkov
- Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
- Edmond J. Safra Center for Bioinformatics, Tel Aviv University, Tel Aviv, Israel
| | - Guy Shapira
- Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
- Edmond J. Safra Center for Bioinformatics, Tel Aviv University, Tel Aviv, Israel
| | - Yazeed Zoabi
- Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
- Edmond J. Safra Center for Bioinformatics, Tel Aviv University, Tel Aviv, Israel
| | - Chen Schiff
- Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Barbara Kloeckener-Gruissem
- Institute of Medical Molecular Genetics, University of Zurich, Zurich, Switzerland
- Department of Biology, ETHZ, Zurich, Switzerland
| | - John Neidhardt
- Human Genetics, Faculty of Medicine and Health Sciences, University of Oldenburg, Germany
- Research Center Neurosensory Science, University Oldenburg, Germany
| | - Noam Shomron
- Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
- Edmond J. Safra Center for Bioinformatics, Tel Aviv University, Tel Aviv, Israel
- Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel
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3
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Mann MW, Fu Y, Gearhart RL, Xu X, Roberts DS, Li Y, Zhou J, Ge Y, Brasier AR. Bromodomain-containing Protein 4 regulates innate inflammation via modulation of alternative splicing. Front Immunol 2023; 14:1212770. [PMID: 37435059 PMCID: PMC10331468 DOI: 10.3389/fimmu.2023.1212770] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2023] [Accepted: 06/05/2023] [Indexed: 07/13/2023] Open
Abstract
Introduction Bromodomain-containing Protein 4 (BRD4) is a transcriptional regulator which coordinates gene expression programs controlling cancer biology, inflammation, and fibrosis. In the context of airway viral infection, BRD4-specific inhibitors (BRD4i) block the release of pro-inflammatory cytokines and prevent downstream epithelial plasticity. Although the chromatin modifying functions of BRD4 in inducible gene expression have been extensively investigated, its roles in post-transcriptional regulation are not well understood. Given BRD4's interaction with the transcriptional elongation complex and spliceosome, we hypothesize that BRD4 is a functional regulator of mRNA processing. Methods To address this question, we combine data-independent analysis - parallel accumulation-serial fragmentation (diaPASEF) with RNA-sequencing to achieve deep and integrated coverage of the proteomic and transcriptomic landscapes of human small airway epithelial cells exposed to viral challenge and treated with BRD4i. Results We discover that BRD4 regulates alternative splicing of key genes, including Interferon-related Developmental Regulator 1 (IFRD1) and X-Box Binding Protein 1 (XBP1), related to the innate immune response and the unfolded protein response (UPR). We identify requirement of BRD4 for expression of serine-arginine splicing factors, splicosome components and the Inositol-Requiring Enzyme 1 IREα affecting immediate early innate response and the UPR. Discussion These findings extend the transcriptional elongation-facilitating actions of BRD4 in control of post-transcriptional RNA processing via modulating splicing factor expression in virus-induced innate signaling.
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Affiliation(s)
- Morgan W. Mann
- Department of Medicine, University of Wisconsin – Madison, Madison, WI, United States
| | - Yao Fu
- Department of Medicine, University of Wisconsin – Madison, Madison, WI, United States
| | - Robert L. Gearhart
- Department of Chemistry, University of Wisconsin – Madison, Madison, WI, United States
| | - Xiaofang Xu
- Department of Medicine, University of Wisconsin – Madison, Madison, WI, United States
| | - David S. Roberts
- Department of Chemistry, University of Wisconsin – Madison, Madison, WI, United States
| | - Yi Li
- Department of Pharmacology and Toxicology, University of Texas Medical Branch, Galveston, TX, United States
| | - Jia Zhou
- Department of Pharmacology and Toxicology, University of Texas Medical Branch, Galveston, TX, United States
| | - Ying Ge
- Department of Chemistry, University of Wisconsin – Madison, Madison, WI, United States
- Department of Cell and Regenerative Biology, University of Wisconsin-Madison, Madison, WI, United States
- Human Proteomics Program, University of Wisconsin-Madison, Madison, WI, United States
| | - Allan R. Brasier
- Department of Medicine, University of Wisconsin – Madison, Madison, WI, United States
- Institute for Clinical and Translational Research, University of Wisconsin-Madison, Madison, WI, United States
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4
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Ye R, Hu N, Cao C, Su R, Xu S, Yang C, Zhou X, Xue Y. Capture RIC-seq reveals positional rules of PTBP1-associated RNA loops in splicing regulation. Mol Cell 2023; 83:1311-1327.e7. [PMID: 36958328 DOI: 10.1016/j.molcel.2023.03.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2022] [Revised: 01/10/2023] [Accepted: 02/27/2023] [Indexed: 03/25/2023]
Abstract
RNA-binding proteins (RBPs) bind at different positions of the pre-mRNA molecules to promote or reduce the usage of a particular exon. Seeking to understand the working principle of these positional effects, we develop a capture RIC-seq (CRIC-seq) method to enrich specific RBP-associated in situ proximal RNA-RNA fragments for deep sequencing. We determine hnRNPA1-, SRSF1-, and PTBP1-associated proximal RNA-RNA contacts and regulatory mechanisms in HeLa cells. Unexpectedly, the 3D RNA map analysis shows that PTBP1-associated loops in individual introns preferentially promote cassette exon splicing by accelerating asymmetric intron removal, whereas the loops spanning across cassette exon primarily repress splicing. These "positional rules" can faithfully predict PTBP1-regulated splicing outcomes. We further demonstrate that cancer-related splicing quantitative trait loci can disrupt RNA loops by reducing PTBP1 binding on pre-mRNAs to cause aberrant splicing in tumors. Our study presents a powerful method for exploring the functions of RBP-associated RNA-RNA proximal contacts in gene regulation and disease.
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Affiliation(s)
- Rong Ye
- Key Laboratory of RNA Biology, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Naijing Hu
- Key Laboratory of RNA Biology, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Changchang Cao
- Key Laboratory of RNA Biology, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Ruibao Su
- Key Laboratory of RNA Biology, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Shihan Xu
- State Key Laboratory of Ophthalmology, Optometry and Vision Science, Wenzhou, Zhejiang 325003, China
| | - Chen Yang
- State Key Laboratory of Ophthalmology, Optometry and Vision Science, Wenzhou, Zhejiang 325003, China
| | - Xiangtian Zhou
- State Key Laboratory of Ophthalmology, Optometry and Vision Science, Wenzhou, Zhejiang 325003, China
| | - Yuanchao Xue
- Key Laboratory of RNA Biology, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China.
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5
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Wang X, You B, Yin F, Chen C, He H, Liu F, Pan Z, Ni X, Pang N, Peng J. A presumed missense variant in the U2AF2 gene causes exon skipping in neurodevelopmental diseases. J Hum Genet 2023; 68:375-382. [PMID: 36747105 DOI: 10.1038/s10038-023-01128-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Revised: 12/14/2022] [Accepted: 01/23/2023] [Indexed: 02/08/2023]
Abstract
U2 small nuclear RNA auxiliary factor 2 (U2AF2) is an indispensable pre-mRNA splicing factor in the early process of splicing. Recently, U2AF2 was reported as a novel candidate gene associated with neurodevelopmental disorders. Herein, we report a patient with a novel presumed heterozygous missense variant in the U2AF2 gene (c.603G>T), who has a similar clinical phenotype as the patient reported before, including epilepsy, intellectual disability, language delay, microcephaly, and hypoplastic corpus callosum. We reviewed the phenotypic and genetic spectrum of patients with U2AF2-related neurological diseases, both newly diagnosed and previously reported. To investigate the possible pathogenesis, EBV-immortalized lymphoblastoid cells were derived from the peripheral blood obtained from the patient and control groups. Furthermore, according to the results of WB, RT-PCR, Q-PCR, and cDNA sequencing of RT-PCR products, the presumed missense variant c.603G>T caused exon 6 skipping in the U2AF2 mRNA transcript and led to a truncated protein (p.E163_E201del). Cell Counting Kit-8 (CCK-8) and cell cycle detection demonstrated that the variant c.603G>T inhibited the proliferation of patient lymphocyte cells compared with the control group. This study is aimed at expanding the phenotypic and genetic spectrum of U2AF2-related neurodevelopmental diseases and investigating the potential effects. This is the first report of the possible pathogenesis of a U2AF2 gene pathogenic variant in a patient with neurodevelopmental diseases and shows that a novel presumed missense variant in the U2AF2 gene causes exon skipping.
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Affiliation(s)
- Xiaole Wang
- Department of Pediatrics, Xiangya Hospital of Central South University, Changsha, Hunan Province, China
| | - Baiyang You
- Department of Physical Medicine & Rehabilitation, Xiangya Hospital of Central South University, Changsha, Hunan Province, China
| | - Fei Yin
- Department of Pediatrics, Xiangya Hospital of Central South University, Changsha, Hunan Province, China.,Clinical Research Center for Children Neurodevelopmental Disabilities of Hunan Province, Changsha, China
| | - Chen Chen
- Department of Pediatrics, Xiangya Hospital of Central South University, Changsha, Hunan Province, China
| | - Hailan He
- Department of Pediatrics, Xiangya Hospital of Central South University, Changsha, Hunan Province, China
| | - Fangyun Liu
- Department of Pediatrics, Xiangya Hospital of Central South University, Changsha, Hunan Province, China
| | - Zou Pan
- Department of Pediatrics, Xiangya Hospital of Central South University, Changsha, Hunan Province, China
| | - Xiaoyuan Ni
- Department of Pediatrics, Xiangya Hospital of Central South University, Changsha, Hunan Province, China
| | - Nan Pang
- Department of Pediatrics, Xiangya Hospital of Central South University, Changsha, Hunan Province, China
| | - Jing Peng
- Department of Pediatrics, Xiangya Hospital of Central South University, Changsha, Hunan Province, China. .,Clinical Research Center for Children Neurodevelopmental Disabilities of Hunan Province, Changsha, China.
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6
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Anil AT, Choudhary K, Pandian R, Gupta P, Thakran P, Singh A, Sharma M, Mishra SK. Splicing of branchpoint-distant exons is promoted by Cactin, Tls1 and the ubiquitin-fold-activated Sde2. Nucleic Acids Res 2022; 50:10000-10014. [PMID: 36095128 PMCID: PMC9508853 DOI: 10.1093/nar/gkac769] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2022] [Revised: 08/22/2022] [Accepted: 08/27/2022] [Indexed: 11/13/2022] Open
Abstract
Intron diversity facilitates regulated gene expression and alternative splicing. Spliceosomes excise introns after recognizing their splicing signals: the 5'-splice site (5'ss), branchpoint (BP) and 3'-splice site (3'ss). The latter two signals are recognized by U2 small nuclear ribonucleoprotein (snRNP) and its accessory factors (U2AFs), but longer spacings between them result in weaker splicing. Here, we show that excision of introns with a BP-distant 3'ss (e.g. rap1 intron 2) requires the ubiquitin-fold-activated splicing regulator Sde2 in Schizosaccharomyces pombe. By monitoring splicing-specific ura4 reporters in a collection of S. pombe mutants, Cay1 and Tls1 were identified as additional regulators of this process. The role of Sde2, Cay1 and Tls1 was further confirmed by increasing BP-3'ss spacings in a canonical tho5 intron. We also examined BP-distant exons spliced independently of these factors and observed that RNA secondary structures possibly bridged the gap between the two signals. These proteins may guide the 3'ss towards the spliceosome's catalytic centre by folding the RNA between the BP and 3'ss. Orthologues of Sde2, Cay1 and Tls1, although missing in the intron-poor Saccharomyces cerevisiae, are present in intron-rich eukaryotes, including humans. This type of intron-specific pre-mRNA splicing appears to have evolved for regulated gene expression and alternative splicing of key heterochromatin factors.
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Affiliation(s)
- Anupa T Anil
- Department of Biological Sciences, Indian Institute of Science Education and Research (IISER) Mohali, Sector 81, 140306 Punjab, India
| | - Karan Choudhary
- Department of Biological Sciences, Indian Institute of Science Education and Research (IISER) Mohali, Sector 81, 140306 Punjab, India
| | - Rakesh Pandian
- Department of Biological Sciences, Indian Institute of Science Education and Research (IISER) Mohali, Sector 81, 140306 Punjab, India
| | - Praver Gupta
- Department of Biological Sciences, Indian Institute of Science Education and Research (IISER) Mohali, Sector 81, 140306 Punjab, India
| | - Poonam Thakran
- Department of Biological Sciences, Indian Institute of Science Education and Research (IISER) Mohali, Sector 81, 140306 Punjab, India
| | - Arashdeep Singh
- Department of Biological Sciences, Indian Institute of Science Education and Research (IISER) Mohali, Sector 81, 140306 Punjab, India
| | - Monika Sharma
- Department of Chemical Sciences, Indian Institute of Science Education and Research (IISER) Mohali, Sector 81, 140306 Punjab, India
| | - Shravan Kumar Mishra
- Department of Biological Sciences, Indian Institute of Science Education and Research (IISER) Mohali, Sector 81, 140306 Punjab, India
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7
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Jones AN, Graß C, Meininger I, Geerlof A, Klostermann M, Zarnack K, Krappmann D, Sattler M. Modulation of pre-mRNA structure by hnRNP proteins regulates alternative splicing of MALT1. SCIENCE ADVANCES 2022; 8:eabp9153. [PMID: 35921415 PMCID: PMC9348792 DOI: 10.1126/sciadv.abp9153] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
Alternative splicing plays key roles for cell type-specific regulation of protein function. It is controlled by cis-regulatory RNA elements that are recognized by RNA binding proteins (RBPs). The MALT1 paracaspase is a key factor of signaling pathways that mediate innate and adaptive immune responses. Alternative splicing of MALT1 is critical for controlling optimal T cell activation. We demonstrate that MALT1 splicing depends on RNA structural elements that sequester the splice sites of the alternatively spliced exon7. The RBPs hnRNP U and hnRNP L bind competitively to stem-loop RNA structures that involve the 5' and 3' splice sites flanking exon7. While hnRNP U stabilizes RNA stem-loop conformations that maintain exon7 skipping, hnRNP L disrupts these RNA elements to facilitate recruitment of the essential splicing factor U2AF2, thereby promoting exon7 inclusion. Our data represent a paradigm for the control of splice site selection by differential RBP binding and modulation of pre-mRNA structure.
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Affiliation(s)
- Alisha N. Jones
- Institute of Structural Biology, Molecular Targets and Therapeutics Center, Helmholtz Zentrum München, Neuherberg, 85764 München, Germany
- Bavarian NMR Center, Department of Chemistry, Technical University of Munich, Garching, 85748 München, Germany
| | - Carina Graß
- Research Unit Cellular Signal Integration, Institute of Molecular Toxicology and Pharmacology, Molecular Targets and Therapeutics Center, Helmholtz Zentrum München, Neuherberg, 85764 München, Germany
| | - Isabel Meininger
- Research Unit Cellular Signal Integration, Institute of Molecular Toxicology and Pharmacology, Molecular Targets and Therapeutics Center, Helmholtz Zentrum München, Neuherberg, 85764 München, Germany
| | - Arie Geerlof
- Institute of Structural Biology, Molecular Targets and Therapeutics Center, Helmholtz Zentrum München, Neuherberg, 85764 München, Germany
| | - Melina Klostermann
- Buchmann Institute for Molecular Life Sciences (BMLS) & Faculty of Biological Sciences, Goethe University Frankfurt, Max-von-Laue-Str. 15, 60438 Frankfurt am Main, Germany
| | - Kathi Zarnack
- Buchmann Institute for Molecular Life Sciences (BMLS) & Faculty of Biological Sciences, Goethe University Frankfurt, Max-von-Laue-Str. 15, 60438 Frankfurt am Main, Germany
| | - Daniel Krappmann
- Research Unit Cellular Signal Integration, Institute of Molecular Toxicology and Pharmacology, Molecular Targets and Therapeutics Center, Helmholtz Zentrum München, Neuherberg, 85764 München, Germany
- Corresponding author. (D.K.); (M.S.)
| | - Michael Sattler
- Institute of Structural Biology, Molecular Targets and Therapeutics Center, Helmholtz Zentrum München, Neuherberg, 85764 München, Germany
- Bavarian NMR Center, Department of Chemistry, Technical University of Munich, Garching, 85748 München, Germany
- Corresponding author. (D.K.); (M.S.)
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8
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Georgakopoulos-Soares I, Parada GE, Hemberg M. Secondary structures in RNA synthesis, splicing and translation. Comput Struct Biotechnol J 2022; 20:2871-2884. [PMID: 35765654 PMCID: PMC9198270 DOI: 10.1016/j.csbj.2022.05.041] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Revised: 05/19/2022] [Accepted: 05/21/2022] [Indexed: 11/30/2022] Open
Abstract
Even though the functional role of mRNA molecules is primarily decided by the nucleotide sequence, several properties are determined by secondary structure conformations. Examples of secondary structures include long range interactions, hairpins, R-loops and G-quadruplexes and they are formed through interactions of non-adjacent nucleotides. Here, we discuss advances in our understanding of how secondary structures can impact RNA synthesis, splicing, translation and mRNA half-life. During RNA synthesis, secondary structures determine RNA polymerase II (RNAPII) speed, thereby influencing splicing. Splicing is also determined by RNA binding proteins and their binding rates are modulated by secondary structures. For the initiation of translation, secondary structures can control the choice of translation start site. Here, we highlight the mechanisms by which secondary structures modulate these processes, discuss advances in technologies to detect and study them systematically, and consider the roles of RNA secondary structures in disease.
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9
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Unique and Repeated Stwintrons (Spliceosomal Twin Introns) in the Hypoxylaceae. J Fungi (Basel) 2022; 8:jof8040397. [PMID: 35448628 PMCID: PMC9024468 DOI: 10.3390/jof8040397] [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: 03/02/2022] [Revised: 04/06/2022] [Accepted: 04/09/2022] [Indexed: 12/04/2022] Open
Abstract
Introns are usually non-coding sequences interrupting open reading frames in pre-mRNAs [D1,2]. Stwintrons are nested spliceosomal introns, where an internal intron splits a second donor sequence into two consecutive splicing reactions leading to mature mRNA. In Hypoxylon sp. CO27-5, 36 highly sequence-similar [D1,2] stwintrons are extant (sister stwintrons). An additional 81 [D1,2] sequence-unrelated stwintrons are described here. Most of them are located at conserved gene positions rooted deep in the Hypoxylaceae. Absence of exonic sequence bias at the exon–stwintron junctions and a very similar phase distribution were noted for both groups. The presence of an underlying sequence symmetry in all 117 stwintrons was striking. This symmetry, more pronounced near the termini of most of the full-length sister stwintrons, may lead to a secondary structure that brings into close proximity the most distal splice sites, the donor of the internal and the acceptor of the external intron. The Hypoxylon stwintrons were overwhelmingly excised by consecutive splicing reactions precisely removing the whole intervening sequence, whereas one excision involving the distal splice sites led to a frameshift. Alternative (mis)splicing took place for both sister and uniquely occurring stwintrons. The extraordinary symmetry of the sister stwintrons thus seems dispensable for the infrequent, direct utilisation of the distal splice sites.
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10
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Wang S, Cheng Y, Liu S, Xu Y, Gao Y, Wang C, Wang Z, Feng T, Lu G, Song J, Xia P, Hao L. A synonymous mutation in IGF-1 impacts the transcription and translation process of gene expression. MOLECULAR THERAPY. NUCLEIC ACIDS 2021; 26:1446-1465. [PMID: 34938600 PMCID: PMC8655398 DOI: 10.1016/j.omtn.2021.08.007] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Accepted: 08/10/2021] [Indexed: 11/18/2022]
Abstract
Insulin-like growth factor 1 (IGF-1) is considered to be a crucial gene in the animal development of bone and body size. In this study, a unique synonymous mutation (c.258 A > G) of the IGF-1 gene was modified with an adenine base editor to observe the growth and developmental situation of mutant mice. Significant expression differences and molecular mechanisms among vectors with different alanine synonymous codons were explored. Although modification of a single synonymous codon rarely interferes with animal phenotypes, we observed that the expression and secretion of IGF-1 were different between 8-week-old homozygous (Ho) and wild-type (WT) mice. In addition, the IGF-1 with optimal codon combinations showed a higher expression content than other codon combination modes at both transcription and translation levels and performed proliferation promotion. The gene stability and translation initiation efficiency also changed significantly. Our findings illustrated that the synonymous mutation altered the IGF-1 gene expression in individual mice and suggested that the synonymous mutation affected the IGF-1 expression and biological function through the transcription and translation processes.
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Affiliation(s)
- S.Y. Wang
- College of Animal Science, Jilin University, Changchun 130062, China
- Beijing Advanced Innovation Centre for Biomedical Engineering, School of Biological Science and Medical Engineering, Beihang University, Beijing, China
| | - Y.Y. Cheng
- Ministry of Health Key Laboratory of Radiobiology, College of Public Health, Jilin University, Changchun, Jilin 130021, China
| | - S.C. Liu
- College of Animal Science, Jilin University, Changchun 130062, China
| | - Y.X. Xu
- College of Animal Science, Jilin University, Changchun 130062, China
| | - Y. Gao
- College of Animal Science, Jilin University, Changchun 130062, China
| | - C.L. Wang
- College of Animal Science, Jilin University, Changchun 130062, China
| | - Z.G. Wang
- College of Animal Science, Jilin University, Changchun 130062, China
| | - T.Q. Feng
- College of Animal Science, Jilin University, Changchun 130062, China
| | - G.H. Lu
- College of Animal Science, Jilin University, Changchun 130062, China
| | - J. Song
- College of Animal Science, Jilin University, Changchun 130062, China
| | - P.J. Xia
- College of Animal Science, Jilin University, Changchun 130062, China
| | - L.L. Hao
- College of Animal Science, Jilin University, Changchun 130062, China
- Corresponding author: Linlin Hao, College of Animal Science, Jilin University, Changchun 130062, China.
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11
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Feng J, Li Y, Zhu L, Zhao Q, Li D, Li Y, Wu T. STAT1 mediated long non-coding RNA LINC00504 influences radio-sensitivity of breast cancer via binding to TAF15 and stabilizing CPEB2 expression. Cancer Biol Ther 2021; 22:630-639. [PMID: 34908514 DOI: 10.1080/15384047.2021.1964320] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022] Open
Abstract
Radiotherapy plays important roles in the treatment of breast cancer (BC), which develops from malignant cells in the breast. Long non-coding RNAs (lncRNAs) have been reported to be implicated in radio-resistance or radio-sensitivity of human cancer, which includes breast cancer. Nevertheless, long intergenic non-protein coding RNA 0504 (LINC00504) has not been investigated in BC. In our study, from RT-qPCR analysis, LINC00504 was found to be up-regulated in BC cells. By conducting in vitro assays, it was confirmed that the knockdown of LINC00504 could enhance the radio-sensitivity of BC cells. The regulatory mechanism of LINC00504 in BC was also verified by chromatin immunoprecipitation (ChIP), RNA immunoprecipitation (RIP) and luciferase reporter assays. From the experimental results, we knew that the up-regulation of LINC00504 was mediated by signal transducer and activator of transcription 1 (STAT1). Moreover, LINC00504 stabilized the expression of cytoplasmic polyadenylation element-binding protein 2 (CPEB2) via binding to TATA-box binding protein associated factor 15 (TAF15). Furthermore, rescue assays validated that LINC00504 participated in regulating the radio-sensitivity of BC cells via up-regulating CPEB2. In summary, our study disclosed that STAT1 could mediate LINC00504 and weaken the radio-sensitivity of BC cells via binding to TAF15 and stabilizing CPEB2 expression.
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Affiliation(s)
- Jinchun Feng
- Department of Breast Surgery, Cancer Hospital Affiliated to Xinjiang Medical University, Urumqi, Xinjiang, China
| | - Yan Li
- Department of Breast Surgery, Hami City Second People's Hospital, Hami, Xinjiang, China
| | - Liping Zhu
- Department of Breast Surgery, Cancer Hospital Affiliated to Xinjiang Medical University, Urumqi, Xinjiang, China
| | - Qian Zhao
- Department of Breast Surgery, Cancer Hospital Affiliated to Xinjiang Medical University, Urumqi, Xinjiang, China
| | - Dan Li
- Department of Breast Surgery, Cancer Hospital Affiliated to Xinjiang Medical University, Urumqi, Xinjiang, China
| | - Yuxiang Li
- Department of Breast Surgery, Cancer Hospital Affiliated to Xinjiang Medical University, Urumqi, Xinjiang, China
| | - Tao Wu
- Department of Breast Surgery, Cancer Hospital Affiliated to Xinjiang Medical University, Urumqi, Xinjiang, China
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12
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Zhang X, Bustos MA, Gross R, Ramos RI, Takeshima T, Mills GB, Yu Q, Hoon DSB. Interleukin enhancer-binding factor 2 promotes cell proliferation and DNA damage response in metastatic melanoma. Clin Transl Med 2021; 11:e608. [PMID: 34709752 PMCID: PMC8516365 DOI: 10.1002/ctm2.608] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Revised: 09/21/2021] [Accepted: 09/27/2021] [Indexed: 12/19/2022] Open
Abstract
BACKGROUND 1q21.3 amplification, which is frequently observed in metastatic melanoma, is associated with cancer progression. Interleukin enhancer-binding factor 2 (ILF2) is located in the 1q21.3 amplified region, but its functional role or contribution to tumour aggressiveness in cutaneous melanoma is unknown. METHODS In silico analyses were performed using the TCGA SKCM dataset with clinical annotations and three melanoma microarray cohorts from the GEO datasets. RNA in situ hybridisation and immunohistochemistry were utilised to validate the gene expression in melanoma tissues. Four stable melanoma cell lines were established for in vitro ILF2 functional characterisation. RESULTS Our results showed that the ILF2 copy number variation (CNV) is positively correlated with ILF2 mRNA expression (r = 0.68, p < .0001). Additionally, ILF2 expression is significantly increased with melanoma progression (p < .0001), and significantly associated with poor overall survival for metastatic melanoma patients (p = .026). The overexpression of ILF2 (ILF2-OV) promotes proliferation in metastatic melanoma cells, whereas ILF2 knockdown decreases proliferation by blocking the cell cycle. Mechanistically, we demonstrated the interaction between ILF2 and the splicing factor U2AF2, whose knockdown reverses the proliferation effects mediated by ILF2-OV. Stage IIIB-C melanoma patients with high ILF2-U2AF2 expression showed significantly shorter overall survival (p = .024). Enhanced ILF2/U2AF2 expression promotes a more efficient DNA-damage repair by increasing RAD50 and ATM mRNA expression. Paradoxically, metastatic melanoma cells with ILF2-OV were more sensitive to ATM inhibitors. CONCLUSION Our study uncovered that ILF2 amplification of the 1q21.3 chromosome is associated with melanoma progression and triggers a functional downstream pathway in metastatic melanoma promoting drug resistance.
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Affiliation(s)
- Xiaoqing Zhang
- Department of Translational Molecular MedicineProvidence Saint John's Health CenterSaint John's Cancer InstituteSanta MonicaCalifornia
| | - Matias A. Bustos
- Department of Translational Molecular MedicineProvidence Saint John's Health CenterSaint John's Cancer InstituteSanta MonicaCalifornia
| | - Rebecca Gross
- Department of Translational Molecular MedicineProvidence Saint John's Health CenterSaint John's Cancer InstituteSanta MonicaCalifornia
| | - Romela Irene Ramos
- Department of Translational Molecular MedicineProvidence Saint John's Health CenterSaint John's Cancer InstituteSanta MonicaCalifornia
| | - Teh‐Ling Takeshima
- Department of Translational Molecular MedicineProvidence Saint John's Health CenterSaint John's Cancer InstituteSanta MonicaCalifornia
| | - Gordon B. Mills
- Department of Cell Development and Cancer BiologyKnight Cancer InstituteOregon Health and Science UniversityPortlandOregon
| | - Qiang Yu
- Agency for Science Technology and Research (A*STAR)Genome Institute of SingaporeBiopolisSingapore
| | - Dave S. B. Hoon
- Department of Translational Molecular MedicineProvidence Saint John's Health CenterSaint John's Cancer InstituteSanta MonicaCalifornia
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13
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Conboy JG. Unannotated splicing regulatory elements in deep intron space. WILEY INTERDISCIPLINARY REVIEWS-RNA 2021; 12:e1656. [PMID: 33887804 DOI: 10.1002/wrna.1656] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 01/06/2021] [Revised: 03/14/2021] [Accepted: 03/23/2021] [Indexed: 12/21/2022]
Abstract
Deep intron space harbors a diverse array of splicing regulatory elements that cooperate with better-known exon-proximal elements to enforce proper tissue-specific and development-specific pre-mRNA processing. Many deep intron elements have been highly conserved through vertebrate evolution, yet remain poorly annotated in the human genome. Recursive splicing exons (RS-exons) and intraexons promote noncanonical, multistep resplicing pathways in long introns, involving transient intermediate structures that are greatly underrepresented in RNA-seq datasets. Decoy splice sites and decoy exons act at a distance to inhibit splicing catalysis at annotated splice sites, with functional consequences such as exon skipping and intron retention. RNA:RNA bridges can juxtapose distant sequences within or across introns to activate deep intron splicing enhancers and silencers, to loop out exons to be skipped, or to select one member of a mutually exclusive set of exons. Similarly, protein bridges mediated by interactions among transcript-bound RNA binding proteins (RBPs) can modulate splicing outcomes. Experimental disruption of deep intron elements serving any of these functions can abrogate normal splicing, strongly suggesting that natural mutations of deep intron elements can do likewise to cause human disease. Understanding noncanonical splicing pathways and discovering deep intron regulatory signals, many of which map hundreds to many thousands of nucleotides from annotated splice junctions, is of great academic interest for basic scientists studying alternative splicing mechanisms. Hopefully, this knowledge coupled with increased analysis of deep intron sequences will also have important medical applications, as better interpretation of deep intron mutations may reveal new disease mechanisms and suggest new therapies. This article is categorized under: RNA Processing > Splicing Regulation/Alternative Splicing.
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Affiliation(s)
- John G Conboy
- Lawrence Berkeley National Laboratory, Biological Systems and Engineering Division, Berkeley, California, USA
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14
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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: 42] [Impact Index Per Article: 14.0] [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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15
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Taylor K, Sobczak K. Intrinsic Regulatory Role of RNA Structural Arrangement in Alternative Splicing Control. Int J Mol Sci 2020; 21:ijms21145161. [PMID: 32708277 PMCID: PMC7404189 DOI: 10.3390/ijms21145161] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Accepted: 07/17/2020] [Indexed: 12/14/2022] Open
Abstract
Alternative splicing is a highly sophisticated process, playing a significant role in posttranscriptional gene expression and underlying the diversity and complexity of organisms. Its regulation is multilayered, including an intrinsic role of RNA structural arrangement which undergoes time- and tissue-specific alterations. In this review, we describe the principles of RNA structural arrangement and briefly decipher its cis- and trans-acting cellular modulators which serve as crucial determinants of biological functionality of the RNA structure. Subsequently, we engage in a discussion about the RNA structure-mediated mechanisms of alternative splicing regulation. On one hand, the impairment of formation of optimal RNA structures may have critical consequences for the splicing outcome and further contribute to understanding the pathomechanism of severe disorders. On the other hand, the structural aspects of RNA became significant features taken into consideration in the endeavor of finding potential therapeutic treatments. Both aspects have been addressed by us emphasizing the importance of ongoing studies in both fields.
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16
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Lemaire S, Fontrodona N, Aubé F, Claude JB, Polvèche H, Modolo L, Bourgeois CF, Mortreux F, Auboeuf D. Characterizing the interplay between gene nucleotide composition bias and splicing. Genome Biol 2019; 20:259. [PMID: 31783898 PMCID: PMC6883713 DOI: 10.1186/s13059-019-1869-y] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2019] [Accepted: 10/28/2019] [Indexed: 12/18/2022] Open
Abstract
BACKGROUND Nucleotide composition bias plays an important role in the 1D and 3D organization of the human genome. Here, we investigate the potential interplay between nucleotide composition bias and the regulation of exon recognition during splicing. RESULTS By analyzing dozens of RNA-seq datasets, we identify two groups of splicing factors that activate either about 3200 GC-rich exons or about 4000 AT-rich exons. We show that splicing factor-dependent GC-rich exons have predicted RNA secondary structures at 5' ss and are dependent on U1 snRNP-associated proteins. In contrast, splicing factor-dependent AT-rich exons have a large number of decoy branch points, SF1- or U2AF2-binding sites and are dependent on U2 snRNP-associated proteins. Nucleotide composition bias also influences local chromatin organization, with consequences for exon recognition during splicing. Interestingly, the GC content of exons correlates with that of their hosting genes, isochores, and topologically associated domains. CONCLUSIONS We propose that regional nucleotide composition bias over several dozens of kilobase pairs leaves a local footprint at the exon level and induces constraints during splicing that can be alleviated by local chromatin organization at the DNA level and recruitment of specific splicing factors at the RNA level. Therefore, nucleotide composition bias establishes a direct link between genome organization and local regulatory processes, like alternative splicing.
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Affiliation(s)
- Sébastien Lemaire
- Laboratory of Biology and Modelling of the Cell, Univ Lyon, ENS de Lyon, Univ Claude Bernard, CNRS UMR 5239, INSERM U1210, 46 Allée d'Italie Site Jacques Monod, F-69007, Lyon, France
| | - Nicolas Fontrodona
- Laboratory of Biology and Modelling of the Cell, Univ Lyon, ENS de Lyon, Univ Claude Bernard, CNRS UMR 5239, INSERM U1210, 46 Allée d'Italie Site Jacques Monod, F-69007, Lyon, France
| | - Fabien Aubé
- Laboratory of Biology and Modelling of the Cell, Univ Lyon, ENS de Lyon, Univ Claude Bernard, CNRS UMR 5239, INSERM U1210, 46 Allée d'Italie Site Jacques Monod, F-69007, Lyon, France
| | - Jean-Baptiste Claude
- Laboratory of Biology and Modelling of the Cell, Univ Lyon, ENS de Lyon, Univ Claude Bernard, CNRS UMR 5239, INSERM U1210, 46 Allée d'Italie Site Jacques Monod, F-69007, Lyon, France
| | | | - Laurent Modolo
- LBMC Biocomputing Center, CNRS UMR 5239, INSERM U1210, 46 Allée d'Italie Site Jacques Monod, F-69007, Lyon, France
| | - Cyril F Bourgeois
- Laboratory of Biology and Modelling of the Cell, Univ Lyon, ENS de Lyon, Univ Claude Bernard, CNRS UMR 5239, INSERM U1210, 46 Allée d'Italie Site Jacques Monod, F-69007, Lyon, France
| | - Franck Mortreux
- Laboratory of Biology and Modelling of the Cell, Univ Lyon, ENS de Lyon, Univ Claude Bernard, CNRS UMR 5239, INSERM U1210, 46 Allée d'Italie Site Jacques Monod, F-69007, Lyon, France
| | - Didier Auboeuf
- Laboratory of Biology and Modelling of the Cell, Univ Lyon, ENS de Lyon, Univ Claude Bernard, CNRS UMR 5239, INSERM U1210, 46 Allée d'Italie Site Jacques Monod, F-69007, Lyon, France.
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17
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Neil CR, Fairbrother WG. Intronic RNA: Ad'junk' mediator of post-transcriptional gene regulation. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2019; 1862:194439. [PMID: 31682938 DOI: 10.1016/j.bbagrm.2019.194439] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/04/2019] [Accepted: 09/30/2019] [Indexed: 01/23/2023]
Abstract
RNA splicing, the process through which intervening segments of noncoding RNA (introns) are excised from pre-mRNAs to allow for the formation of a mature mRNA product, has long been appreciated for its capacity to add complexity to eukaryotic proteomes. However, evidence suggests that the utility of this process extends beyond protein output and provides cells with a dynamic tool for gene regulation. In this review, we aim to highlight the role that intronic RNA plays in mediating specific splicing outcomes in pre-mRNA processing, as well as explore an emerging class of stable intronic sequences that have been observed to act in gene expression control. Building from underlying flexibility in both sequence and structure, intronic RNA provides mechanisms for post-transcriptional gene regulation that are amenable to the tissue and condition specific needs of eukaryotic cells. This article is part of a Special Issue entitled: RNA structure and splicing regulation edited by Francisco Baralle, Ravindra Singh and Stefan Stamm.
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Affiliation(s)
- Christopher R Neil
- Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence, RI, United States of America
| | - William G Fairbrother
- Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence, RI, United States of America; Center for Computational Molecular Biology, Brown University, Providence, RI, United States of America.
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18
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Královicová J, Ševcíková I, Stejskalová E, Obuca M, Hiller M, Stanek D, Vorechovský I. PUF60-activated exons uncover altered 3' splice-site selection by germline missense mutations in a single RRM. Nucleic Acids Res 2019; 46:6166-6187. [PMID: 29788428 PMCID: PMC6093180 DOI: 10.1093/nar/gky389] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2018] [Accepted: 05/01/2018] [Indexed: 12/27/2022] Open
Abstract
PUF60 is a splicing factor that binds uridine (U)-rich tracts and facilitates association of the U2 small nuclear ribonucleoprotein with primary transcripts. PUF60 deficiency (PD) causes a developmental delay coupled with intellectual disability and spinal, cardiac, ocular and renal defects, but PD pathogenesis is not understood. Using RNA-Seq, we identify human PUF60-regulated exons and show that PUF60 preferentially acts as their activator. PUF60-activated internal exons are enriched for Us upstream of their 3′ splice sites (3′ss), are preceded by longer AG dinucleotide exclusion zones and more distant branch sites, with a higher probability of unpaired interactions across a typical branch site location as compared to control exons. In contrast, PUF60-repressed exons show U-depletion with lower estimates of RNA single-strandedness. We also describe PUF60-regulated, alternatively spliced isoforms encoding other U-bound splicing factors, including PUF60 partners, suggesting that they are co-regulated in the cell, and identify PUF60-regulated exons derived from transposed elements. PD-associated amino-acid substitutions, even within a single RNA recognition motif (RRM), altered selection of competing 3′ss and branch points of a PUF60-dependent exon and the 3′ss choice was also influenced by alternative splicing of PUF60. Finally, we propose that differential distribution of RNA processing steps detected in cells lacking PUF60 and the PUF60-paralog RBM39 is due to the RBM39 RS domain interactions. Together, these results provide new insights into regulation of exon usage by the 3′ss organization and reveal that germline mutation heterogeneity in RRMs can enhance phenotypic variability at the level of splice-site and branch-site selection.
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Affiliation(s)
- Jana Královicová
- University of Southampton Faculty of Medicine, Southampton SO16 6YD, UK.,Slovak Academy of Sciences, Centre for Biosciences, 840 05 Bratislava, Slovak Republic
| | - Ivana Ševcíková
- Slovak Academy of Sciences, Centre for Biosciences, 840 05 Bratislava, Slovak Republic
| | - Eva Stejskalová
- Czech Academy of Sciences, Institute of Molecular Genetics, 142 20 Prague, Czech Republic
| | - Mina Obuca
- Czech Academy of Sciences, Institute of Molecular Genetics, 142 20 Prague, Czech Republic
| | - Michael Hiller
- Max Planck Institute of Molecular Cell Biology and Genetics and Max Planck Institute for the Physics of Complex Systems, Dresden, Germany
| | - David Stanek
- Czech Academy of Sciences, Institute of Molecular Genetics, 142 20 Prague, Czech Republic
| | - Igor Vorechovský
- University of Southampton Faculty of Medicine, Southampton SO16 6YD, UK
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19
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Andrews RJ, Moss WN. Computational approaches for the discovery of splicing regulatory RNA structures. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2019; 1862:194380. [PMID: 31048028 DOI: 10.1016/j.bbagrm.2019.04.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Revised: 04/15/2019] [Accepted: 04/16/2019] [Indexed: 12/14/2022]
Abstract
Global RNA structure and local functional motifs mediate interactions important in determining the rates and patterns of mRNA splicing. In this review, we overview approaches for the computational prediction of RNA secondary structure with a special emphasis on the discovery of motifs important to RNA splicing. The process of identifying and modeling potential splicing regulatory structures is illustrated using a recently-developed approach for RNA structural motif discovery, the ScanFold pipeline, which is applied to the identification of a known splicing regulatory structure in influenza virus.
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Affiliation(s)
- Ryan J Andrews
- Roy J. Carver Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, 2437 Pammel Drive, Ames, IA 50011, USA
| | - Walter N Moss
- Roy J. Carver Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, 2437 Pammel Drive, Ames, IA 50011, USA.
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20
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Kim SW, Taggart AJ, Heintzelman C, Cygan KJ, Hull CG, Wang J, Shrestha B, Fairbrother WG. Widespread intra-dependencies in the removal of introns from human transcripts. Nucleic Acids Res 2017; 45:9503-9513. [PMID: 28934498 PMCID: PMC5766209 DOI: 10.1093/nar/gkx661] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2016] [Accepted: 07/24/2017] [Indexed: 01/19/2023] Open
Abstract
Research into the problem of splice site selection has followed a reductionist approach focused on how individual splice sites are recognized. Early applications of information theory uncovered an inconsistency. Human splice signals do not contain enough information to explain the observed fidelity of splicing. Here, we conclude that introns do not necessarily contain ‘missing’ information but rather may require definition from neighboring processing events. For example, there are known cases where an intronic mutation disrupts the splicing of not only the local intron but also adjacent introns. We present a genome-wide measurement of the order of splicing within human transcripts. The observed order of splicing cannot be explained by a simple kinetic model. Simulations reveal a bias toward a particular, transcript-specific order of intron removal in human genes. We validate an extreme class of intron that can only splice in a multi-intron context. Special categories of splicing such as exon circularization, first and last intron processing, alternative 5 and 3′ss usage and exon skipping are marked by distinct patterns of ordered intron removal. Excessive intronic length and silencer density tend to delay splicing. Shorter introns that contain enhancers splice early.
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Affiliation(s)
- Seong Won Kim
- Department of Molecular and Cellular Biology, Brown University, Providence, RI 02903, USA
| | - Allison J Taggart
- Department of Molecular and Cellular Biology, Brown University, Providence, RI 02903, USA
| | - Claire Heintzelman
- Department of Molecular and Cellular Biology, Brown University, Providence, RI 02903, USA
| | - Kamil J Cygan
- Center for Computational Molecular Biology, Brown University, Providence, RI 02903, USA
| | - Caitlin G Hull
- Department of Molecular and Cellular Biology, Brown University, Providence, RI 02903, USA
| | - Jing Wang
- Department of Molecular and Cellular Biology, Brown University, Providence, RI 02903, USA
| | - Barsha Shrestha
- Department of Molecular and Cellular Biology, Brown University, Providence, RI 02903, USA
| | - William G Fairbrother
- Department of Molecular and Cellular Biology, Brown University, Providence, RI 02903, USA.,Center for Computational Molecular Biology, Brown University, Providence, RI 02903, USA
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21
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Soemedi R, Cygan KJ, Rhine CL, Glidden DT, Taggart AJ, Lin CL, Fredericks AM, Fairbrother WG. The effects of structure on pre-mRNA processing and stability. Methods 2017; 125:36-44. [PMID: 28595983 DOI: 10.1016/j.ymeth.2017.06.001] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2017] [Revised: 05/31/2017] [Accepted: 06/01/2017] [Indexed: 12/16/2022] Open
Abstract
Pre-mRNA molecules can form a variety of structures, and both secondary and tertiary structures have important effects on processing, function and stability of these molecules. The prediction of RNA secondary structure is a challenging problem and various algorithms that use minimum free energy, maximum expected accuracy and comparative evolutionary based methods have been developed to predict secondary structures. However, these tools are not perfect, and this remains an active area of research. The secondary structure of pre-mRNA molecules can have an enhancing or inhibitory effect on pre-mRNA splicing. An example of enhancing structure can be found in a novel class of introns in zebrafish. About 10% of zebrafish genes contain a structured intron that forms a bridging hairpin that enforces correct splice site pairing. Negative examples of splicing include local structures around splice sites that decrease splicing efficiency and potentially cause mis-splicing leading to disease. Splicing mutations are a frequent cause of hereditary disease. The transcripts of disease genes are significantly more structured around the splice sites, and point mutations that increase the local structure often cause splicing disruptions. Post-splicing, RNA secondary structure can also affect the stability of the spliced intron and regulatory RNA interference pathway intermediates, such as pre-microRNAs. Additionally, RNA secondary structure has important roles in the innate immune defense against viruses. Finally, tertiary structure can also play a large role in pre-mRNA splicing. One example is the G-quadruplex structure, which, similar to secondary structure, can either enhance or inhibit splicing through mechanisms such as creating or obscuring RNA binding protein sites.
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Affiliation(s)
- Rachel Soemedi
- Department of Molecular Biology, Cell Biology and Biochemistry, Brown University, 70 Ship Street, Providence, RI 02903, USA; Center for Computational Molecular Biology, Brown University, 115 Waterman Street, Providence, RI 02912, USA.
| | - Kamil J Cygan
- Department of Molecular Biology, Cell Biology and Biochemistry, Brown University, 70 Ship Street, Providence, RI 02903, USA; Center for Computational Molecular Biology, Brown University, 115 Waterman Street, Providence, RI 02912, USA.
| | - Christy L Rhine
- Department of Molecular Biology, Cell Biology and Biochemistry, Brown University, 70 Ship Street, Providence, RI 02903, USA.
| | - David T Glidden
- Department of Molecular Biology, Cell Biology and Biochemistry, Brown University, 70 Ship Street, Providence, RI 02903, USA; Center for Computational Molecular Biology, Brown University, 115 Waterman Street, Providence, RI 02912, USA.
| | - Allison J Taggart
- Department of Molecular Biology, Cell Biology and Biochemistry, Brown University, 70 Ship Street, Providence, RI 02903, USA.
| | - Chien-Ling Lin
- Department of Molecular Biology, Cell Biology and Biochemistry, Brown University, 70 Ship Street, Providence, RI 02903, USA.
| | - Alger M Fredericks
- Department of Molecular Biology, Cell Biology and Biochemistry, Brown University, 70 Ship Street, Providence, RI 02903, USA.
| | - William G Fairbrother
- Department of Molecular Biology, Cell Biology and Biochemistry, Brown University, 70 Ship Street, Providence, RI 02903, USA; Center for Computational Molecular Biology, Brown University, 115 Waterman Street, Providence, RI 02912, USA.
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22
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Pathogenic variants that alter protein code often disrupt splicing. Nat Genet 2017; 49:848-855. [PMID: 28416821 PMCID: PMC6679692 DOI: 10.1038/ng.3837] [Citation(s) in RCA: 142] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2016] [Accepted: 03/16/2017] [Indexed: 12/18/2022]
Abstract
The lack of tools to identify causative variants from sequencing data greatly limits the promise of Precision Medicine. Previous studies suggest one-third of disease alleles alter splicing. We discovered that splicing defects cluster in diseases (e.g. haploinsufficient genes). We analyzed 4,964 published disease-causing exonic mutations using a Massively Parallel Splicing Assay (MaPSy) that showed 81% concordance rate with patient tissue splicing. ~10% of exonic mutations altered splicing, mostly by disrupting multiple stages of the spliceosome assembly. We present the first large-scale characterization of exonic splicing mutations using a novel technology that facilitates variant classification that keeps pace with variant discovery.
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23
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Abstract
Pre-mRNA splicing is a key post-transcriptional regulation process in which introns are excised and exons are ligated together. A novel class of structured intron was recently discovered in fish. Simple expansions of complementary AC and GT dimers at opposite boundaries of an intron were found to form a bridging structure, thereby enforcing correct splice site pairing across the intron. In some fish introns, the RNA structures are strong enough to bypass the need of regulatory protein factors for splicing. Here, we discuss the prevalence and potential functions of highly structured introns. In humans, structured introns usually arise through the co-occurrence of C and G-rich repeats at intron boundaries. We explore the potentially instructive example of the HLA receptor genes. In HLA pre-mRNA, structured introns flank the exons that encode the highly polymorphic β sheet cleft, making the processing of the transcript robust to variants that disrupt splicing factor binding. While selective forces that have shaped HLA receptor are fairly atypical, numerous other highly polymorphic genes that encode receptors contain structured introns. Finally, we discuss how the elevated mutation rate associated with the simple repeats that often compose structured intron can make structured introns themselves rapidly evolving elements.
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Affiliation(s)
- Chien-Ling Lin
- a Molecular Biology, Cell Biology and Biochemistry, Brown University , Providence , RI , USA
| | - Allison J Taggart
- a Molecular Biology, Cell Biology and Biochemistry, Brown University , Providence , RI , USA
| | - William G Fairbrother
- a Molecular Biology, Cell Biology and Biochemistry, Brown University , Providence , RI , USA.,b Center for Computational Molecular Biology, Brown University , Providence , RI , USA.,c Hassenfeld Child Health Innovation Institute of Brown University , Providence , RI , USA
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