1
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Riccardi F, Romano G, Licastro D, Pagani F. Age-dependent regulation of ELP1 exon 20 splicing in Familial Dysautonomia by RNA Polymerase II kinetics and chromatin structure. PLoS One 2024; 19:e0298965. [PMID: 38829854 PMCID: PMC11146744 DOI: 10.1371/journal.pone.0298965] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2023] [Accepted: 02/01/2024] [Indexed: 06/05/2024] Open
Abstract
Familial Dysautonomia (FD) is a rare disease caused by ELP1 exon 20 skipping. Here we clarify the role of RNA Polymerase II (RNAPII) and chromatin on this splicing event. A slow RNAPII mutant and chromatin-modifying chemicals that reduce the rate of RNAPII elongation induce exon skipping whereas chemicals that create a more relaxed chromatin exon inclusion. In the brain of a mouse transgenic for the human FD-ELP1 we observed on this gene an age-dependent decrease in the RNAPII density profile that was most pronounced on the alternative exon, a robust increase in the repressive marks H3K27me3 and H3K9me3 and a decrease of H3K27Ac, together with a progressive reduction in ELP1 exon 20 inclusion level. In HEK 293T cells, selective drug-induced demethylation of H3K27 increased RNAPII elongation on ELP1 and SMN2, promoted the inclusion of the corresponding alternative exons, and, by RNA-sequencing analysis, induced changes in several alternative splicing events. These data suggest a co-transcriptional model of splicing regulation in which age-dependent changes in H3K27me3/Ac modify the rate of RNAPII elongation and affect processing of ELP1 alternative exon 20.
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Affiliation(s)
- Federico Riccardi
- Human Molecular Genetics, International Centre for Genetic Engineering and Biotechnology, Padriciano, Trieste, Italy
| | - Giulia Romano
- Human Molecular Genetics, International Centre for Genetic Engineering and Biotechnology, Padriciano, Trieste, Italy
| | - Danilo Licastro
- Laboratorio di Genomica ed Epigenomica, AREA Science Park, Padriciano, Trieste, Italy
| | - Franco Pagani
- Human Molecular Genetics, International Centre for Genetic Engineering and Biotechnology, Padriciano, Trieste, Italy
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2
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Chen Y, Liu D, Li X, Nie K, Yan S, Peng H, Zhuang Y, Sun M. Aggressive alternative splicing events discovered in cecum ligation and puncture induced lung injury. Biochem Biophys Res Commun 2023; 655:90-96. [PMID: 36933312 DOI: 10.1016/j.bbrc.2023.03.002] [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: 02/17/2023] [Revised: 02/28/2023] [Accepted: 03/01/2023] [Indexed: 03/09/2023]
Abstract
AIMS Acute lung injury (ALI) induced by sepsis and its complications have high morbidity and mortality rates globally. The objective of this study was to enhance our understanding of the underlying mechanism of ALI by identifying potential splicing events that are regulated in this condition. MATERIALS AND METHODS The CLP mouse model was utilized for mRNA sequencing, and the expression and splicing data were analyzed. Verification of the changes in expression and splicing induced by CLP was conducted using qPCR and RT-PCR. RESULTS Our results showed that splicing-related genes were regulated, suggesting that splicing regulation may be a key mechanism in ALI. We also found that more than 2900 genes displayed alternative splicing in the lungs of mice with sepsis. Using RT-PCR, we verified that TLR4 and other genes had differential splicing isoforms in the lungs of mice with sepsis. We confirmed the presence of TLR4-s in the lungs of mice with sepsis using RNA-fluorescence in situ hybridization. CONCLUSION Our results suggest that sepsis-induced ALI can significantly alter splicing in the lungs of mice. The list of DASGs and splicing factors is valuable for further study in the search for new treatment approaches for sepsis-induced ALI.
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Affiliation(s)
- Yuanzhuo Chen
- Department of Emergency, Shanghai Tenth People's Hospital, School of Medicine Tongji University, Shanghai, 200072, China
| | - Dan Liu
- Department of Emergency, Shanghai Tenth People's Hospital, School of Medicine Tongji University, Shanghai, 200072, China
| | - Xiaofeng Li
- Department of Emergency, Shanghai Tenth People's Hospital, School of Medicine Tongji University, Shanghai, 200072, China
| | - Ke Nie
- Department of Emergency, Shanghai Tenth People's Hospital, School of Medicine Tongji University, Shanghai, 200072, China
| | - Songjuan Yan
- Department of Emergency, Shanghai Tenth People's Hospital, School of Medicine Tongji University, Shanghai, 200072, China
| | - Hu Peng
- Department of Emergency, Shanghai Tenth People's Hospital, School of Medicine Tongji University, Shanghai, 200072, China
| | - Yugang Zhuang
- Department of Emergency, Shanghai Tenth People's Hospital, School of Medicine Tongji University, Shanghai, 200072, China.
| | - Mingming Sun
- Department of Emergency, Shanghai Tenth People's Hospital, School of Medicine Tongji University, Shanghai, 200072, China.
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3
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Morini E, Chekuri A, Logan EM, Bolduc JM, Kirchner EG, Salani M, Krauson AJ, Narasimhan J, Gabbeta V, Grover S, Dakka A, Mollin A, Jung SP, Zhao X, Zhang N, Zhang S, Arnold M, Woll MG, Naryshkin NA, Weetall M, Slaugenhaupt SA. Development of an oral treatment that rescues gait ataxia and retinal degeneration in a phenotypic mouse model of familial dysautonomia. Am J Hum Genet 2023; 110:531-547. [PMID: 36809767 PMCID: PMC10027479 DOI: 10.1016/j.ajhg.2023.01.019] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2022] [Accepted: 01/30/2023] [Indexed: 02/22/2023] Open
Abstract
Familial dysautonomia (FD) is a rare neurodegenerative disease caused by a splicing mutation in elongator acetyltransferase complex subunit 1 (ELP1). This mutation leads to the skipping of exon 20 and a tissue-specific reduction of ELP1, mainly in the central and peripheral nervous systems. FD is a complex neurological disorder accompanied by severe gait ataxia and retinal degeneration. There is currently no effective treatment to restore ELP1 production in individuals with FD, and the disease is ultimately fatal. After identifying kinetin as a small molecule able to correct the ELP1 splicing defect, we worked on its optimization to generate novel splicing modulator compounds (SMCs) that can be used in individuals with FD. Here, we optimize the potency, efficacy, and bio-distribution of second-generation kinetin derivatives to develop an oral treatment for FD that can efficiently pass the blood-brain barrier and correct the ELP1 splicing defect in the nervous system. We demonstrate that the novel compound PTC258 efficiently restores correct ELP1 splicing in mouse tissues, including brain, and most importantly, prevents the progressive neuronal degeneration that is characteristic of FD. Postnatal oral administration of PTC258 to the phenotypic mouse model TgFD9;Elp1Δ20/flox increases full-length ELP1 transcript in a dose-dependent manner and leads to a 2-fold increase in functional ELP1 in the brain. Remarkably, PTC258 treatment improves survival, gait ataxia, and retinal degeneration in the phenotypic FD mice. Our findings highlight the great therapeutic potential of this novel class of small molecules as an oral treatment for FD.
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Affiliation(s)
- Elisabetta Morini
- Center for Genomic Medicine, Massachusetts General Hospital Research Institute, Boston, MA, USA; Department of Neurology, Massachusetts General Hospital Research Institute and Harvard Medical School, Boston, MA, USA.
| | - Anil Chekuri
- Center for Genomic Medicine, Massachusetts General Hospital Research Institute, Boston, MA, USA; Department of Neurology, Massachusetts General Hospital Research Institute and Harvard Medical School, Boston, MA, USA; Grousbeck Gene Therapy Center, Schepens Eye Research Institute and Massachusetts Eye and Ear Infirmary, Boston, MA, USA
| | - Emily M Logan
- Center for Genomic Medicine, Massachusetts General Hospital Research Institute, Boston, MA, USA
| | - Jessica M Bolduc
- Center for Genomic Medicine, Massachusetts General Hospital Research Institute, Boston, MA, USA
| | - Emily G Kirchner
- Center for Genomic Medicine, Massachusetts General Hospital Research Institute, Boston, MA, USA
| | - Monica Salani
- Center for Genomic Medicine, Massachusetts General Hospital Research Institute, Boston, MA, USA
| | - Aram J Krauson
- Center for Genomic Medicine, Massachusetts General Hospital Research Institute, Boston, MA, USA
| | | | | | | | - Amal Dakka
- PTC Therapeutics, Inc., South Plainfield, NJ 07080, USA
| | - Anna Mollin
- PTC Therapeutics, Inc., South Plainfield, NJ 07080, USA
| | | | - Xin Zhao
- PTC Therapeutics, Inc., South Plainfield, NJ 07080, USA
| | - Nanjing Zhang
- PTC Therapeutics, Inc., South Plainfield, NJ 07080, USA
| | - Sophie Zhang
- PTC Therapeutics, Inc., South Plainfield, NJ 07080, USA
| | | | | | | | - Marla Weetall
- PTC Therapeutics, Inc., South Plainfield, NJ 07080, USA
| | - Susan A Slaugenhaupt
- Center for Genomic Medicine, Massachusetts General Hospital Research Institute, Boston, MA, USA; Department of Neurology, Massachusetts General Hospital Research Institute and Harvard Medical School, Boston, MA, USA.
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4
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Tolman Z, Chaverra M, George L, Lefcort F. Elp1 is required for development of visceral sensory peripheral and central circuitry. Dis Model Mech 2022; 15:275184. [PMID: 35481599 PMCID: PMC9187870 DOI: 10.1242/dmm.049274] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Accepted: 04/20/2022] [Indexed: 11/23/2022] Open
Abstract
Cardiovascular instability and a blunted respiratory drive in hypoxic conditions are hallmark features of the genetic sensory and autonomic neuropathy, familial dysautonomia (FD). FD results from a mutation in the gene ELP1, the encoded protein of which is a scaffolding subunit of the six-subunit Elongator complex. In mice, we and others have shown that Elp1 is essential for the normal development of neural crest-derived dorsal root ganglia sensory neurons. Whether Elp1 is also required for development of ectodermal placode-derived visceral sensory receptors, which are required for normal baroreception and chemosensory responses, has not been investigated. Using mouse models for FD, we here show that the entire circuitry underlying baroreception and chemoreception is impaired due to a requirement for Elp1 in the visceral sensory neuron ganglia, as well as for normal peripheral target innervation, and in their central nervous system synaptic partners in the medulla. Thus, Elp1 is required in both placode- and neural crest-derived sensory neurons, and its reduction aborts the normal development of neuronal circuitry essential for autonomic homeostasis and interoception. This article has an associated First Person interview with the first author of the paper. Summary: Our data indicate that Elp1 is required in both placode- and neural crest-derived sensory neurons, and that it exerts comparable effects, including survival, axonal morphology and target innervation in both lineages.
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Affiliation(s)
- Zariah Tolman
- Department of Microbiology and Cell Biology, Montana State University, Bozeman, MT 59717, USA
| | - Marta Chaverra
- Department of Microbiology and Cell Biology, Montana State University, Bozeman, MT 59717, USA
| | - Lynn George
- Department of Microbiology and Cell Biology, Montana State University, Bozeman, MT 59717, USA.,Department of Biological and Physical Sciences, Montana State University Billings, Billings, MT 59101, USA
| | - Frances Lefcort
- Department of Microbiology and Cell Biology, Montana State University, Bozeman, MT 59717, USA
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5
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Cheng Z, He X, Zou F, Xu ZE, Li C, Liu H, Miao J. Identification of Novel Mutations in Chinese Infants With Citrullinemia. Front Genet 2022; 13:783799. [PMID: 35309121 PMCID: PMC8929347 DOI: 10.3389/fgene.2022.783799] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Accepted: 02/15/2022] [Indexed: 12/30/2022] Open
Abstract
Citrullinemia is a rare autosomal recessive disorder characterized by elevated concentrations of citrulline in the blood resulting from malfunction of the urea cycle. It is categorized into two types, types I and II, which are caused by argininosuccinate synthase 1 (ASS1), and citrin (SLC25A13) gene mutations, respectively. In this study, we performed genetic analysis on nine Chinese infants with citrullinemia using next-generation sequencing, which identified a novel mutation (p.Leu313Met) and a rare mutation (p.Thr323Ile, rs1250895424) of ASS1. We also found a novel splicing mutation of SLC25A13: c.1311 + 4_+7del. Functional analysis of the ASS1 missense mutations showed that both significantly impaired the enzyme activity of ASS1, with the p. Thr323Ile mutation clearly affecting the interaction between ASS1 and protein arginine methyltransferase 7 (PRMT7). These findings expand the mutational spectrum of ASS1 and SLC25A13, and further our understanding of the molecular genetic mechanism of citrullinemia in the Chinese population.
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Affiliation(s)
- Zhi Cheng
- Key Laboratory of Birth Defects and Reproductive Health of the National Health and Family Planning Commission (Chongqing Population and Family Planning Science and Technology Research Institute), Chongqing, China
- College of Basic Medical Sciences, Chongqing Medical University, Chongqing, China
| | - Xiwen He
- College of Basic Medical Sciences, Chongqing Medical University, Chongqing, China
| | - Fa Zou
- College of Basic Medical Sciences, Chongqing Medical University, Chongqing, China
| | - Zhen-E Xu
- Department of Neonatology, Children’s Hospital of Chongqing Medical University, Chongqing, China
- National Clinical Research Center for Child Health and Disorders, Ministry of Education Key Laboratory of Child Development and Disorders, Chongqing Key Laboratory of Pediatrics, Chongqing, China
| | - Chun Li
- Department of Neonatology, Children’s Hospital of Chongqing Medical University, Chongqing, China
- National Clinical Research Center for Child Health and Disorders, Ministry of Education Key Laboratory of Child Development and Disorders, Chongqing Key Laboratory of Pediatrics, Chongqing, China
| | - Hao Liu
- Neonatal Disease Screening Center, Chongqing Health Center for Women and Children, Chongqing, China
| | - Jingkun Miao
- Neonatal Disease Screening Center, Chongqing Health Center for Women and Children, Chongqing, China
- *Correspondence: Jingkun Miao,
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6
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Liu Q, Fang L, Wu C. Alternative Splicing and Isoforms: From Mechanisms to Diseases. Genes (Basel) 2022; 13:genes13030401. [PMID: 35327956 PMCID: PMC8951537 DOI: 10.3390/genes13030401] [Citation(s) in RCA: 29] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2022] [Revised: 02/21/2022] [Accepted: 02/22/2022] [Indexed: 11/16/2022] Open
Abstract
Alternative splicing of pre-mRNA is a key mechanism for increasing the complexity of proteins in humans, causing a diversity of expression of transcriptomes and proteomes in a tissue-specific manner. Alternative splicing is regulated by a variety of splicing factors. However, the changes and errors of splicing regulation caused by splicing factors are strongly related to many diseases, something which represents one of this study’s main interests. Further understanding of alternative splicing regulation mediated by cellular factors is also a prospective choice to develop specific drugs for targeting the dynamic RNA splicing process. In this review, we firstly concluded the basic principle of alternative splicing. Afterwards, we showed how splicing isoforms affect physiological activities through specific disease examples. Finally, the available treatment methods relative to adjusting splicing activities have been summarized.
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7
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Abstract
In Eukarya, immature mRNA transcripts (pre-mRNA) often contain coding sequences, or exons, interleaved by non-coding sequences, or introns. Introns are removed upon splicing, and further regulation of the retained exons leads to alternatively spliced mRNA. The splicing reaction requires the stepwise assembly of the spliceosome, a macromolecular machine composed of small nuclear ribonucleoproteins (snRNPs). This review focuses on the early stage of spliceosome assembly, when U1 snRNP defines each intron 5’-splice site (5ʹss) in the pre-mRNA. We first introduce the splicing reaction and the impact of alternative splicing on gene expression regulation. Thereafter, we extensively discuss splicing descriptors that influence the 5ʹss selection by U1 snRNP, such as sequence determinants, and interactions mediated by U1-specific proteins or U1 small nuclear RNA (U1 snRNA). We also include examples of diseases that affect the 5ʹss selection by U1 snRNP, and discuss recent therapeutic advances that manipulate U1 snRNP 5ʹss selectivity with antisense oligonucleotides and small-molecule splicing switches.
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Affiliation(s)
- Florian Malard
- Inserm U1212, CNRS UMR5320, ARNA Laboratory, University of Bordeaux, Bordeaux Cedex, France
| | - Cameron D Mackereth
- Inserm U1212, CNRS UMR5320, ARNA Laboratory, University of Bordeaux, Bordeaux Cedex, France
| | - Sébastien Campagne
- Inserm U1212, CNRS UMR5320, ARNA Laboratory, University of Bordeaux, Bordeaux Cedex, France
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8
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Ajiro M, Awaya T, Kim YJ, Iida K, Denawa M, Tanaka N, Kurosawa R, Matsushima S, Shibata S, Sakamoto T, Studer R, Krainer AR, Hagiwara M. Therapeutic manipulation of IKBKAP mis-splicing with a small molecule to cure familial dysautonomia. Nat Commun 2021; 12:4507. [PMID: 34301951 PMCID: PMC8302731 DOI: 10.1038/s41467-021-24705-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Accepted: 06/21/2021] [Indexed: 01/10/2023] Open
Abstract
Approximately half of genetic disease-associated mutations cause aberrant splicing. However, a widely applicable therapeutic strategy to splicing diseases is yet to be developed. Here, we analyze the mechanism whereby IKBKAP-familial dysautonomia (FD) exon 20 inclusion is specifically promoted by a small molecule splice modulator, RECTAS, even though IKBKAP-FD exon 20 has a suboptimal 5' splice site due to the IVS20 + 6 T > C mutation. Knockdown experiments reveal that exon 20 inclusion is suppressed in the absence of serine/arginine-rich splicing factor 6 (SRSF6) binding to an intronic splicing enhancer in intron 20. We show that RECTAS directly interacts with CDC-like kinases (CLKs) and enhances SRSF6 phosphorylation. Consistently, exon 20 splicing is bidirectionally manipulated by targeting cellular CLK activity with RECTAS versus CLK inhibitors. The therapeutic potential of RECTAS is validated in multiple FD disease models. Our study indicates that small synthetic molecules affecting phosphorylation state of SRSFs is available as a new therapeutic modality for mechanism-oriented precision medicine of splicing diseases.
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Affiliation(s)
- Masahiko Ajiro
- Department of Drug Discovery Medicine, Kyoto University Graduate School of Medicine, Kyoto, Japan.,Department of Anatomy and Developmental Biology, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Tomonari Awaya
- Department of Anatomy and Developmental Biology, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Young Jin Kim
- Cold Spring Harbor Laboratory, Cold Spring Harbor, NY, USA
| | - Kei Iida
- Medical Research Support Center, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Masatsugu Denawa
- Medical Research Support Center, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Nobuo Tanaka
- Medical Research Support Center, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Ryo Kurosawa
- Department of Anatomy and Developmental Biology, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Shingo Matsushima
- Department of Drug Discovery Medicine, Kyoto University Graduate School of Medicine, Kyoto, Japan.,Department of Anatomy and Developmental Biology, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Saiko Shibata
- Department of Drug Discovery Medicine, Kyoto University Graduate School of Medicine, Kyoto, Japan.,Department of Anatomy and Developmental Biology, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Tetsunori Sakamoto
- Department of Anatomy and Developmental Biology, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Rolenz Studer
- Center for Stem Cell Biology, Sloan Kettering Institute, New York, NY, USA
| | | | - Masatoshi Hagiwara
- Department of Drug Discovery Medicine, Kyoto University Graduate School of Medicine, Kyoto, Japan. .,Department of Anatomy and Developmental Biology, Kyoto University Graduate School of Medicine, Kyoto, Japan.
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9
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A deep learning approach to identify gene targets of a therapeutic for human splicing disorders. Nat Commun 2021; 12:3332. [PMID: 34099697 PMCID: PMC8185002 DOI: 10.1038/s41467-021-23663-2] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2020] [Accepted: 05/07/2021] [Indexed: 01/16/2023] Open
Abstract
Pre-mRNA splicing is a key controller of human gene expression. Disturbances in splicing due to mutation lead to dysregulated protein expression and contribute to a substantial fraction of human disease. Several classes of splicing modulator compounds (SMCs) have been recently identified and establish that pre-mRNA splicing represents a target for therapy. We describe herein the identification of BPN-15477, a SMC that restores correct splicing of ELP1 exon 20. Using transcriptome sequencing from treated fibroblast cells and a machine learning approach, we identify BPN-15477 responsive sequence signatures. We then leverage this model to discover 155 human disease genes harboring ClinVar mutations predicted to alter pre-mRNA splicing as targets for BPN-15477. Splicing assays confirm successful correction of splicing defects caused by mutations in CFTR, LIPA, MLH1 and MAPT. Subsequent validations in two disease-relevant cellular models demonstrate that BPN-15477 increases functional protein, confirming the clinical potential of our predictions.
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10
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Varela P, Caldas MM, Pesquero JB. Novel GLA Mutation Promotes Intron Inclusion Leading to Fabry Disease. Front Genet 2019; 10:783. [PMID: 31611903 PMCID: PMC6777637 DOI: 10.3389/fgene.2019.00783] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2019] [Accepted: 07/24/2019] [Indexed: 01/28/2023] Open
Abstract
Fabry disease (FD) is a rare and underdiagnosed X-linked disorder resulting from the deficient activity of the lysosomal hydrolase α-galactosidase A, which leads to storage of complex glycosphingolipids inside of lysosomes in critical organs and tissues, impairing their functions and consequently resulting in a progressive multisystem disease. FD is caused by mutations in the GLA gene, and only 4.6% of described mutations are located in the splice site regions. RNA splicing is an essential step to the formation of functional proteins, and mutations in splice site regions can cause formation of aberrant transcripts leading to disease. Here we report a novel GLA insertion at position c.801+3 in intron 5 (c.801+2_801+3insT) in a Brazilian family with suspicion of FD. The index case, a 46-year-old male, presented undetectable α-galactosidase A activity. Analysis of blood cDNA found two aberrant GLA transcripts. In the first transcript, a novel donor splice site was created promoting formation of an intron inclusion with 37 bp. The splice site was not recognized in the second transcript and the intron 5 was not excised. The wild-type transcript was not formed and both aberrant transcripts lead to a premature stop codon. Despite not being in the canonical site, this new mutation disrupts existing 5’ splice site and produces two aberrant transcripts leading to FD.
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Affiliation(s)
- Patrícia Varela
- Center for Research and Molecular Diagnostic of Genetic Diseases - Department of Biophysics, Federal University of São Paulo, São Paulo, Brazil
| | | | - João Bosco Pesquero
- Center for Research and Molecular Diagnostic of Genetic Diseases - Department of Biophysics, Federal University of São Paulo, São Paulo, Brazil
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11
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Bruun GH, Bang JMV, Christensen LL, Brøner S, Petersen USS, Guerra B, Grønning AGB, Doktor TK, Andresen BS. Blocking of an intronic splicing silencer completely rescues IKBKAP exon 20 splicing in familial dysautonomia patient cells. Nucleic Acids Res 2019; 46:7938-7952. [PMID: 29762696 PMCID: PMC6125618 DOI: 10.1093/nar/gky395] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2017] [Accepted: 04/30/2018] [Indexed: 12/22/2022] Open
Abstract
Familial dysautonomia (FD) is a severe genetic disorder causing sensory and autonomic dysfunction. It is predominantly caused by a c.2204+6T>C mutation in the IKBKAP gene. This mutation decreases the 5′ splice site strength of IKBKAP exon 20 leading to exon 20 skipping and decreased amounts of full-length IKAP protein. We identified a binding site for the splicing regulatory protein hnRNP A1 downstream of the IKBKAP exon 20 5′-splice site. We show that hnRNP A1 binds to this splicing regulatory element (SRE) and that two previously described inhibitory SREs inside IKBKAP exon 20 are also bound by hnRNP A1. Knockdown of hnRNP A1 in FD patient fibroblasts increases IKBKAP exon 20 inclusion demonstrating that hnRNP A1 is a negative regulator of IKBKAP exon 20 splicing. Furthermore, by mutating the SREs in an IKBKAP minigene we show that all three SREs cause hnRNP A1-mediated exon repression. We designed splice switching oligonucleotides (SSO) that blocks the intronic hnRNP A1 binding site, and demonstrate that this completely rescues splicing of IKBKAP exon 20 in FD patient fibroblasts and increases the amounts of IKAP protein. We propose that this may be developed into a potential new specific treatment of FD.
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Affiliation(s)
- Gitte H Bruun
- Department of Biochemistry and Molecular Biology and The Villum Center for Bioanalytical Sciences, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark
| | - Jeanne M V Bang
- Department of Biochemistry and Molecular Biology and The Villum Center for Bioanalytical Sciences, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark
| | - Lise L Christensen
- Department of Biochemistry and Molecular Biology and The Villum Center for Bioanalytical Sciences, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark
| | - Sabrina Brøner
- Department of Biochemistry and Molecular Biology and The Villum Center for Bioanalytical Sciences, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark
| | - Ulrika S S Petersen
- Department of Biochemistry and Molecular Biology and The Villum Center for Bioanalytical Sciences, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark
| | - Barbara Guerra
- Department of Biochemistry and Molecular Biology and The Villum Center for Bioanalytical Sciences, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark
| | - Alexander G B Grønning
- Department of Biochemistry and Molecular Biology and The Villum Center for Bioanalytical Sciences, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark
| | - Thomas K Doktor
- Department of Biochemistry and Molecular Biology and The Villum Center for Bioanalytical Sciences, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark
| | - Brage S Andresen
- Department of Biochemistry and Molecular Biology and The Villum Center for Bioanalytical Sciences, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark
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12
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Moye AR, Bedoni N, Cunningham JG, Sanzhaeva U, Tucker ES, Mathers P, Peter VG, Quinodoz M, Paris LP, Coutinho-Santos L, Camacho P, Purcell MG, Winkelmann AC, Foster JA, Pugacheva EN, Rivolta C, Ramamurthy V. Mutations in ARL2BP, a protein required for ciliary microtubule structure, cause syndromic male infertility in humans and mice. PLoS Genet 2019; 15:e1008315. [PMID: 31425546 PMCID: PMC6715254 DOI: 10.1371/journal.pgen.1008315] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2019] [Revised: 08/29/2019] [Accepted: 07/17/2019] [Indexed: 12/30/2022] Open
Abstract
Cilia are evolutionarily conserved hair-like structures with a wide spectrum of key biological roles, and their dysfunction has been linked to a growing class of genetic disorders, known collectively as ciliopathies. Many strides have been made towards deciphering the molecular causes for these diseases, which have in turn expanded the understanding of cilia and their functional roles. One recently-identified ciliary gene is ARL2BP, encoding the ADP-Ribosylation Factor Like 2 Binding Protein. In this study, we have identified multiple ciliopathy phenotypes associated with mutations in ARL2BP in human patients and in a mouse knockout model. Our research demonstrates that spermiogenesis is impaired, resulting in abnormally shaped heads, shortened and mis-assembled sperm tails, as well as in loss of axonemal doublets. Additional phenotypes in the mouse included enlarged ventricles of the brain and situs inversus. Mouse embryonic fibroblasts derived from knockout animals revealed delayed depolymerization of primary cilia. Our results suggest that ARL2BP is required for the structural maintenance of cilia as well as of the sperm flagellum, and that its deficiency leads to syndromic ciliopathy. The flagellated tails of sperm cells require a stringent developmental process that is essential for motility and fertility. The components that comprise the sperm tail assemble in regulated steps with protein processing, transport, and structural assembly dependent on each other for sperm tail maturity. In this work, we have identified ARL2BP, a previously retinal-associated protein, to be essential for sperm tail development and assembly. We show that without functional ARL2BP in humans or mice, sperm tails fail to develop, starting with the assembly of the core microtubular structure within the tail. Loss of ARL2BP also effects other ciliated cells, indicating a unique role for ARL2BP in ciliary microtubule formation. This research on ARL2BP provides further understanding on the links between vision and fertility. This work also demonstrates how genomic studies for human patients and murine models can coincide to provide greater insight into disease.
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Affiliation(s)
- Abigail R. Moye
- Department of Ophthalmology, West Virginia University, Morgantown, United States of America
- Department of Biochemistry, West Virginia University, Morgantown, United States of America
| | - Nicola Bedoni
- Department of Computational Biology, Unit of Medical Genetics, University of Lausanne, Lausanne, Switzerland
| | - Jessica G. Cunningham
- Rockefeller Neurosciences Institute, West Virginia University, Morgantown, WV, United States of America
| | - Urikhan Sanzhaeva
- Department of Biochemistry, West Virginia University, Morgantown, United States of America
| | - Eric S. Tucker
- Rockefeller Neurosciences Institute, West Virginia University, Morgantown, WV, United States of America
| | - Peter Mathers
- Department of Ophthalmology, West Virginia University, Morgantown, United States of America
- Department of Biochemistry, West Virginia University, Morgantown, United States of America
- Rockefeller Neurosciences Institute, West Virginia University, Morgantown, WV, United States of America
| | - Virginie G. Peter
- Department of Computational Biology, Unit of Medical Genetics, University of Lausanne, Lausanne, Switzerland
| | - Mathieu Quinodoz
- Department of Computational Biology, Unit of Medical Genetics, University of Lausanne, Lausanne, Switzerland
| | - Liliana P. Paris
- Department of Ophthalmology, Instituto de Oftalmologia Dr Gama Pinto, Lisbon, Portugal
| | - Luísa Coutinho-Santos
- Department of Ophthalmology, Instituto de Oftalmologia Dr Gama Pinto, Lisbon, Portugal
| | - Pedro Camacho
- Department of Ophthalmology, Instituto de Oftalmologia Dr Gama Pinto, Lisbon, Portugal
| | - Madeleine G. Purcell
- Department of Biology, Randolph-Macon College, Ashland, VA, United States of America
| | - Abbie C. Winkelmann
- Department of Biology, Randolph-Macon College, Ashland, VA, United States of America
| | - James A. Foster
- Department of Biology, Randolph-Macon College, Ashland, VA, United States of America
| | - Elena N. Pugacheva
- Department of Biochemistry, West Virginia University, Morgantown, United States of America
| | - Carlo Rivolta
- Department of Computational Biology, Unit of Medical Genetics, University of Lausanne, Lausanne, Switzerland
- Department of Genetics and Genome Biology, University of Leicester, Leicester, United Kingdom
- Clinical Research Center, Institute of Molecular and Clinical Ophthalmology Basel (IOB), Basel, Switzerland
- Department of Ophthalmology, University Hospital Basel, Switzerland
- * E-mail: (CR); (VR)
| | - Visvanathan Ramamurthy
- Department of Ophthalmology, West Virginia University, Morgantown, United States of America
- Department of Biochemistry, West Virginia University, Morgantown, United States of America
- Rockefeller Neurosciences Institute, West Virginia University, Morgantown, WV, United States of America
- * E-mail: (CR); (VR)
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13
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Neueder A. RNA-Mediated Disease Mechanisms in Neurodegenerative Disorders. J Mol Biol 2018; 431:1780-1791. [PMID: 30597161 DOI: 10.1016/j.jmb.2018.12.012] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2018] [Revised: 12/14/2018] [Accepted: 12/16/2018] [Indexed: 12/16/2022]
Abstract
RNA is accurately entangled in virtually all pathways that maintain cellular homeostasis. To name but a few, RNA is the "messenger" between DNA encoded information and the resulting proteins. Furthermore, RNAs regulate diverse processes by forming DNA::RNA or RNA::RNA interactions. Finally, RNA itself can be the scaffold for ribonucleoprotein complexes, for example, ribosomes or cellular bodies. Consequently, disruption of any of these processes can lead to disease. This review describes known and emerging RNA-based disease mechanisms like interference with regular splicing, the anomalous appearance of RNA-protein complexes and uncommon RNA species, as well as non-canonical translation. Due to the complexity and entanglement of the above-mentioned pathways, only few drugs are available that target RNA-based disease mechanisms. However, advances in our understanding how RNA is involved in and modulates cellular homeostasis might pave the way to novel treatments.
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Affiliation(s)
- Andreas Neueder
- Experimental Neurology, Department of Neurology, Ulm University, 89081 Ulm, Germany.
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14
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15
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Zhang S, Samocha KE, Rivas MA, Karczewski KJ, Daly E, Schmandt B, Neale BM, MacArthur DG, Daly MJ. Base-specific mutational intolerance near splice sites clarifies the role of nonessential splice nucleotides. Genome Res 2018; 28:968-974. [PMID: 29858273 PMCID: PMC6028136 DOI: 10.1101/gr.231902.117] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2017] [Accepted: 05/31/2018] [Indexed: 12/20/2022]
Abstract
Variation in RNA splicing (i.e., alternative splicing) plays an important role in many diseases. Variants near 5′ and 3′ splice sites often affect splicing, but the effects of these variants on splicing and disease have not been fully characterized beyond the two “essential” splice nucleotides flanking each exon. Here we provide quantitative measurements of tolerance to mutational disruptions by position and reference allele–alternative allele combinations. We show that certain reference alleles are particularly sensitive to mutations, regardless of the alternative alleles into which they are mutated. Using public RNA-seq data, we demonstrate that individuals carrying such variants have significantly lower levels of the correctly spliced transcript, compared to individuals without them, and confirm that these specific substitutions are highly enriched for known Mendelian mutations. Our results propose a more refined definition of the “splice region” and offer a new way to prioritize and provide functional interpretation of variants identified in diagnostic sequencing and association studies.
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Affiliation(s)
- Sidi Zhang
- Analytic and Translational Genetics Unit, Massachusetts General Hospital, Boston, Massachusetts 02114, USA.,Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, Massachusetts 02142, USA.,Program in Biological and Biomedical Sciences, Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Kaitlin E Samocha
- Analytic and Translational Genetics Unit, Massachusetts General Hospital, Boston, Massachusetts 02114, USA.,Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, Massachusetts 02142, USA.,Program in Biological and Biomedical Sciences, Harvard Medical School, Boston, Massachusetts 02115, USA.,Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, Massachusetts 02142, USA
| | - Manuel A Rivas
- Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, Massachusetts 02142, USA
| | - Konrad J Karczewski
- Analytic and Translational Genetics Unit, Massachusetts General Hospital, Boston, Massachusetts 02114, USA.,Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, Massachusetts 02142, USA
| | - Emma Daly
- Analytic and Translational Genetics Unit, Massachusetts General Hospital, Boston, Massachusetts 02114, USA
| | - Ben Schmandt
- Analytic and Translational Genetics Unit, Massachusetts General Hospital, Boston, Massachusetts 02114, USA
| | - Benjamin M Neale
- Analytic and Translational Genetics Unit, Massachusetts General Hospital, Boston, Massachusetts 02114, USA.,Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, Massachusetts 02142, USA.,Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, Massachusetts 02142, USA
| | - Daniel G MacArthur
- Analytic and Translational Genetics Unit, Massachusetts General Hospital, Boston, Massachusetts 02114, USA.,Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, Massachusetts 02142, USA
| | - Mark J Daly
- Analytic and Translational Genetics Unit, Massachusetts General Hospital, Boston, Massachusetts 02114, USA.,Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, Massachusetts 02142, USA.,Stanley Center for Psychiatric Research, Broad Institute of MIT and Harvard, Cambridge, Massachusetts 02142, USA.,Institute for Molecular Medicine Finland (FIMM), 00290 Helsinki, Finland
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16
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Anna A, Monika G. Splicing mutations in human genetic disorders: examples, detection, and confirmation. J Appl Genet 2018; 59:253-268. [PMID: 29680930 PMCID: PMC6060985 DOI: 10.1007/s13353-018-0444-7] [Citation(s) in RCA: 377] [Impact Index Per Article: 62.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2018] [Revised: 04/08/2018] [Accepted: 04/10/2018] [Indexed: 01/02/2023]
Abstract
Precise pre-mRNA splicing, essential for appropriate protein translation, depends on the presence of consensus "cis" sequences that define exon-intron boundaries and regulatory sequences recognized by splicing machinery. Point mutations at these consensus sequences can cause improper exon and intron recognition and may result in the formation of an aberrant transcript of the mutated gene. The splicing mutation may occur in both introns and exons and disrupt existing splice sites or splicing regulatory sequences (intronic and exonic splicing silencers and enhancers), create new ones, or activate the cryptic ones. Usually such mutations result in errors during the splicing process and may lead to improper intron removal and thus cause alterations of the open reading frame. Recent research has underlined the abundance and importance of splicing mutations in the etiology of inherited diseases. The application of modern techniques allowed to identify synonymous and nonsynonymous variants as well as deep intronic mutations that affected pre-mRNA splicing. The bioinformatic algorithms can be applied as a tool to assess the possible effect of the identified changes. However, it should be underlined that the results of such tests are only predictive, and the exact effect of the specific mutation should be verified in functional studies. This article summarizes the current knowledge about the "splicing mutations" and methods that help to identify such changes in clinical diagnosis.
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Affiliation(s)
- Abramowicz Anna
- Department of Medical Genetics, Institute of Mother and Child, Kasprzaka 17a, 01-211, Warsaw, Poland
| | - Gos Monika
- Department of Medical Genetics, Institute of Mother and Child, Kasprzaka 17a, 01-211, Warsaw, Poland.
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17
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Ohe K, Yoshida M, Nakano-Kobayashi A, Hosokawa M, Sako Y, Sakuma M, Okuno Y, Usui T, Ninomiya K, Nojima T, Kataoka N, Hagiwara M. RBM24 promotes U1 snRNP recognition of the mutated 5' splice site in the IKBKAP gene of familial dysautonomia. RNA (NEW YORK, N.Y.) 2017; 23:1393-1403. [PMID: 28592461 PMCID: PMC5558909 DOI: 10.1261/rna.059428.116] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/06/2016] [Accepted: 05/25/2017] [Indexed: 06/07/2023]
Abstract
The 5' splice site mutation (IVS20+6T>C) of the inhibitor of κ light polypeptide gene enhancer in B cells, kinase complex-associated protein (IKBKAP) gene in familial dysautonomia (FD) is at the sixth intronic nucleotide of the 5' splice site. It is known to weaken U1 snRNP recognition and result in an aberrantly spliced mRNA product in neuronal tissue, but normally spliced mRNA in other tissues. Aberrantly spliced IKBKAP mRNA abrogates IKK complex-associated protein (IKAP)/elongator protein 1 (ELP1) expression and results in a defect of neuronal cell development in FD. To elucidate the tissue-dependent regulatory mechanism, we screened an expression library of major RNA-binding proteins (RBPs) with our mammalian dual-color splicing reporter system and identified RBM24 as a regulator. RBM24 functioned as a cryptic intronic splicing enhancer binding to an element (IVS20+13-29) downstream from the intronic 5' splice site mutation in the IKBKAP gene and promoted U1 snRNP recognition only to the mutated 5' splice site (and not the wild-type 5' splice site). Our results show that tissue-specific expression of RBM24 can explain the neuron-specific aberrant splicing of IKBKAP exon 20 in familial dysautonomia, and that ectopic expression of RBM24 in neuronal tissue could be a novel therapeutic target of the disease.
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Affiliation(s)
- Kenji Ohe
- Department of Anatomy and Developmental Biology, Kyoto University Graduate School of Medicine, Sakyo-ku, Kyoto 606-8501, Japan
- Training Program of Leaders for Integrated Medical System for Fruitful Healthy-Longevity Society (LIMS), Kyoto University Graduate School of Medicine, Sakyo-ku, Kyoto 606-8501, Japan
| | - Mayumi Yoshida
- Department of Anatomy and Developmental Biology, Kyoto University Graduate School of Medicine, Sakyo-ku, Kyoto 606-8501, Japan
| | - Akiko Nakano-Kobayashi
- Department of Anatomy and Developmental Biology, Kyoto University Graduate School of Medicine, Sakyo-ku, Kyoto 606-8501, Japan
| | - Motoyasu Hosokawa
- Department of Anatomy and Developmental Biology, Kyoto University Graduate School of Medicine, Sakyo-ku, Kyoto 606-8501, Japan
| | - Yukiya Sako
- Department of Anatomy and Developmental Biology, Kyoto University Graduate School of Medicine, Sakyo-ku, Kyoto 606-8501, Japan
| | - Maki Sakuma
- Department of Anatomy and Developmental Biology, Kyoto University Graduate School of Medicine, Sakyo-ku, Kyoto 606-8501, Japan
| | - Yukiko Okuno
- Medical Research Support Center, Kyoto University Graduate School of Medicine, Sakyo-ku, Kyoto 606-8501, Japan
| | - Tomomi Usui
- Laboratory of Gene Expression, School of Biomedical Science, Tokyo Medical and Dental University, Bunkyo-ku, Tokyo 113-8510, Japan
| | - Kensuke Ninomiya
- Department of Anatomy and Developmental Biology, Kyoto University Graduate School of Medicine, Sakyo-ku, Kyoto 606-8501, Japan
| | - Takayuki Nojima
- Sir William Dunn School of Pathology, University of Oxford, Oxford OX1 3RE, United Kingdom
| | - Naoyuki Kataoka
- Laboratory for Malignancy Control Research, Medical Innovation Center, Kyoto University Graduate School of Medicine, Sakyo-ku, Kyoto 606-8507, Japan
- Laboratory of Cell Regulation, Departments of Applied Animal Sciences and Applied Biological Chemistry, Graduate School of Agriculture and Life Sciences, The University of Tokyo, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Masatoshi Hagiwara
- Department of Anatomy and Developmental Biology, Kyoto University Graduate School of Medicine, Sakyo-ku, Kyoto 606-8501, Japan
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18
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Faulty RNA splicing: consequences and therapeutic opportunities in brain and muscle disorders. Hum Genet 2017; 136:1215-1235. [DOI: 10.1007/s00439-017-1802-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2017] [Accepted: 04/13/2017] [Indexed: 12/12/2022]
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19
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Kataoka N. Modulation of aberrant splicing in human RNA diseases by chemical compounds. Hum Genet 2017; 136:1237-1245. [PMID: 28364159 DOI: 10.1007/s00439-017-1789-4] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2017] [Accepted: 03/25/2017] [Indexed: 01/09/2023]
Abstract
Pre-mRNA splicing is an essential step for gene expression in higher eukaryotes. Alternative splicing contributes to diversity of the expressed proteins from the limited number of genes. Disruption of splicing regulation often results in hereditary and sporadic diseases called as 'RNA diseases'. Modulation of splicing by small chemical compounds and nucleic acids has been tried to target aberrant splicing in those diseases. Several RNA diseases and splicing-target therapeutic approaches will be briefly introduced in this review. Accumulating knowledge about molecular mechanism of aberrant splicing and their correction by chemical compounds is important not only for RNA biologists, but also for clinicians who desire therapies for those diseases.
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Affiliation(s)
- Naoyuki Kataoka
- Laboratory of Cell Regulation, Departments of Applied Animal Sciences and Applied Biological Chemistry, Graduate School of Agriculture and Life Sciences, The University of Tokyo, Tokyo, Japan.
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20
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Kolaj-Robin O, Séraphin B. Structures and Activities of the Elongator Complex and Its Cofactors. RNA MODIFICATION 2017; 41:117-149. [DOI: 10.1016/bs.enz.2017.03.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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21
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Dietrich P, Dragatsis I. Familial Dysautonomia: Mechanisms and Models. Genet Mol Biol 2016; 39:497-514. [PMID: 27561110 PMCID: PMC5127153 DOI: 10.1590/1678-4685-gmb-2015-0335] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2015] [Accepted: 03/16/2016] [Indexed: 11/22/2022] Open
Abstract
Hereditary Sensory and Autonomic Neuropathies (HSANs) compose a heterogeneous group of genetic disorders characterized by sensory and autonomic dysfunctions. Familial Dysautonomia (FD), also known as HSAN III, is an autosomal recessive disorder that affects 1/3,600 live births in the Ashkenazi Jewish population. The major features of the disease are already present at birth and are attributed to abnormal development and progressive degeneration of the sensory and autonomic nervous systems. Despite clinical interventions, the disease is inevitably fatal. FD is caused by a point mutation in intron 20 of the IKBKAP gene that results in severe reduction in expression of IKAP, its encoded protein. In vitro and in vivo studies have shown that IKAP is involved in multiple intracellular processes, and suggest that failed target innervation and/or impaired neurotrophic retrograde transport are the primary causes of neuronal cell death in FD. However, FD is far more complex, and appears to affect several other organs and systems in addition to the peripheral nervous system. With the recent generation of mouse models that recapitulate the molecular and pathological features of the disease, it is now possible to further investigate the mechanisms underlying different aspects of the disorder, and to test novel therapeutic strategies.
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Affiliation(s)
- Paula Dietrich
- Department of Physiology, The University of Tennessee, Memphis, TN, USA
| | - Ioannis Dragatsis
- Department of Physiology, The University of Tennessee, Memphis, TN, USA
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22
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Abstract
The human transcriptome is composed of a vast RNA population that undergoes further diversification by splicing. Detecting specific splice sites in this large sequence pool is the responsibility of the major and minor spliceosomes in collaboration with numerous splicing factors. This complexity makes splicing susceptible to sequence polymorphisms and deleterious mutations. Indeed, RNA mis-splicing underlies a growing number of human diseases with substantial societal consequences. Here, we provide an overview of RNA splicing mechanisms followed by a discussion of disease-associated errors, with an emphasis on recently described mutations that have provided new insights into splicing regulation. We also discuss emerging strategies for splicing-modulating therapy.
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Affiliation(s)
- Marina M Scotti
- Department of Molecular Genetics and Microbiology, Center for NeuroGenetics and the Genetics Institute, University of Florida, College of Medicine, Gainesville, Florida 32610-3610 USA
| | - Maurice S Swanson
- Department of Molecular Genetics and Microbiology, Center for NeuroGenetics and the Genetics Institute, University of Florida, College of Medicine, Gainesville, Florida 32610-3610 USA
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23
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Daguenet E, Dujardin G, Valcárcel J. The pathogenicity of splicing defects: mechanistic insights into pre-mRNA processing inform novel therapeutic approaches. EMBO Rep 2015; 16:1640-55. [PMID: 26566663 DOI: 10.15252/embr.201541116] [Citation(s) in RCA: 102] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2015] [Accepted: 10/12/2015] [Indexed: 12/22/2022] Open
Abstract
Removal of introns from pre-mRNA precursors (pre-mRNA splicing) is a necessary step for the expression of most genes in multicellular organisms, and alternative patterns of intron removal diversify and regulate the output of genomic information. Mutation or natural variation in pre-mRNA sequences, as well as in spliceosomal components and regulatory factors, has been implicated in the etiology and progression of numerous pathologies. These range from monogenic to multifactorial genetic diseases, including metabolic syndromes, muscular dystrophies, neurodegenerative and cardiovascular diseases, and cancer. Understanding the molecular mechanisms associated with splicing-related pathologies can provide key insights into the normal function and physiological context of the complex splicing machinery and establish sound basis for novel therapeutic approaches.
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Affiliation(s)
- Elisabeth Daguenet
- Centre de Regulació Genòmica (CRG), The Barcelona Institute of Science and Technology, Barcelona, Spain Universitat Pompeu-Fabra, Barcelona, Spain
| | - Gwendal Dujardin
- Centre de Regulació Genòmica (CRG), The Barcelona Institute of Science and Technology, Barcelona, Spain Universitat Pompeu-Fabra, Barcelona, Spain
| | - Juan Valcárcel
- Centre de Regulació Genòmica (CRG), The Barcelona Institute of Science and Technology, Barcelona, Spain Universitat Pompeu-Fabra, Barcelona, Spain Institució Catalana de Recerca i Estudis Avançats (ICREA), Barcelona, Spain
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24
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Rectifying RNA splicing errors in hereditary neurodegenerative disease. Proc Natl Acad Sci U S A 2015; 112:2637-8. [PMID: 25691745 DOI: 10.1073/pnas.1500976112] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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25
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Rectifier of aberrant mRNA splicing recovers tRNA modification in familial dysautonomia. Proc Natl Acad Sci U S A 2015; 112:2764-9. [PMID: 25675486 DOI: 10.1073/pnas.1415525112] [Citation(s) in RCA: 78] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Familial dysautonomia (FD), a hereditary sensory and autonomic neuropathy, is caused by missplicing of exon 20, resulting from an intronic mutation in the inhibitor of kappa light polypeptide gene enhancer in B cells, kinase complex-associated protein (IKBKAP) gene encoding IKK complex-associated protein (IKAP)/elongator protein 1 (ELP1). A newly established splicing reporter assay allowed us to visualize pathogenic splicing in cells and to screen small chemicals for the ability to correct the aberrant splicing of IKBKAP. Using this splicing reporter, we screened our chemical libraries and identified a compound, rectifier of aberrant splicing (RECTAS), that rectifies the aberrant IKBKAP splicing in cells from patients with FD. Here, we found that the levels of modified uridine at the wobble position in cytoplasmic tRNAs are reduced in cells from patients with FD and that treatment with RECTAS increases the expression of IKAP and recovers the tRNA modifications. These findings suggest that the missplicing of IKBKAP results in reduced tRNA modifications in patients with FD and that RECTAS is a promising therapeutic drug candidate for FD.
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26
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A targeted oligonucleotide enhancer of SMN2 exon 7 splicing forms competing quadruplex and protein complexes in functional conditions. Cell Rep 2014; 9:193-205. [PMID: 25263560 PMCID: PMC4536295 DOI: 10.1016/j.celrep.2014.08.051] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2013] [Revised: 07/17/2014] [Accepted: 08/21/2014] [Indexed: 01/20/2023] Open
Abstract
The use of oligonucleotides to activate the splicing of selected exons is limited by a poor understanding of the mechanisms affected. A targeted bifunctional oligonucleotide enhancer of splicing (TOES) anneals to SMN2 exon 7 and carries an exonic splicing enhancer (ESE) sequence. We show that it stimulates splicing specifically of intron 6 in the presence of repressing sequences in intron 7. Complementarity to the 5' end of exon 7 increases U2AF65 binding, but the ESE sequence is required for efficient recruitment of U2 snRNP. The ESE forms at least three coexisting discrete states: a quadruplex, a complex containing only hnRNP F/H, and a complex enriched in the activator SRSF1. Neither hnRNP H nor quadruplex formation contributes to ESE activity. The results suggest that splicing limited by weak signals can be rescued by rapid exchange of TOES oligonucleotides in various complexes and raise the possibility that SR proteins associate transiently with ESEs.
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27
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Cheishvili D, Laiba E, Rekhtman D, Claman A, Razin A, Maayan C. Dynamic changes in IKBKAP mRNA levels during crisis of familial dysautonomia patients. Auton Neurosci 2014; 180:59-65. [DOI: 10.1016/j.autneu.2013.10.009] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2013] [Revised: 09/29/2013] [Accepted: 10/24/2013] [Indexed: 11/27/2022]
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28
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Liu B, Anderson SL, Qiu J, Rubin BY. Cardiac glycosides correct aberrant splicing of IKBKAP-encoded mRNA in familial dysautonomia derived cells by suppressing expression of SRSF3. FEBS J 2013; 280:3632-46. [PMID: 23711097 DOI: 10.1111/febs.12355] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2013] [Revised: 04/30/2013] [Accepted: 05/21/2013] [Indexed: 12/11/2022]
Abstract
The ability to modulate the production of the wild-type transcript in cells bearing the splice-altering familial dysautonomia (FD) causing mutation in the IKBKAP gene prompted a study of the impact of a panel of pharmaceuticals on the splicing of this transcript, which revealed the ability of the cardiac glycoside digoxin to increase the production of the wild-type, exon-20-containing, IKBKAP-encoded transcript and the full-length IκB-kinase-complex-associated protein in FD-derived cells. Characterization of the cis elements and trans factors involved in the digoxin-mediated effect on splicing reveals that this response is dependent on an SRSF3 binding site(s) located in the intron 5' of the alternatively spliced exon and that digoxin mediates its effect by suppressing the level of the SRSF3 protein. Characterization of the digoxin-mediated effect on the RNA splicing process was facilitated by the identification of several RNA splicing events in which digoxin treatment mediates the enhanced inclusion of exonic sequence. Moreover, we demonstrate the ability of digoxin to impact the splicing process in neuronal cells, a cell type profoundly impacted by FD. This study represents the first demonstration that digoxin possesses splice-altering capabilities that are capable of reversing the impact of the FD-causing mutation. These findings support the clinical evaluation of the impact of digoxin on the FD patient population.
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Affiliation(s)
- Bo Liu
- Laboratory for Familial Dysautonomia Research, Department of Biological Sciences, Fordham University, Bronx, NY 10458, USA
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Boone N, Bergon A, Loriod B, Devèze A, Nguyen C, Axelrod FB, Ibrahim EC. Genome-wide analysis of familial dysautonomia and kinetin target genes with patient olfactory ecto-mesenchymal stem cells. Hum Mutat 2012; 33:530-40. [PMID: 22190446 DOI: 10.1002/humu.22010] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2011] [Accepted: 12/08/2011] [Indexed: 11/10/2022]
Abstract
Familial dysautonomia (FD) is a rare inherited neurodegenerative disorder. The most common mutation is a c.2204+6T>C transition in the 5' splice site (5'ss) of IKBKAP intron 20, which causes a tissue-specific skipping of exon 20, resulting in lower synthesis of IKAP/hELP1 protein. To better understand the specificity of neuron loss in FD, we modeled the molecular mechanisms of IKBKAP mRNA splicing by studying human olfactory ecto-mesenchymal stem cells (hOE-MSCs) derived from FD patient nasal biopsies. We explored how the modulation of IKBKAP mRNA alternative splicing impacts the transcriptome at the genome-wide level. We found that the FD transcriptional signature was highly associated with biological functions related to the development of the nervous system. In addition, we identified target genes of kinetin, a plant cytokinin that corrects IKBKAP mRNA splicing and increases the expression of IKAP/hELP1. We identified this compound as a putative regulator of splicing factors and added new evidence for a sequence-specific correction of splicing. In conclusion, hOE-MSCs isolated from FD patients represent a promising avenue for modeling the altered genetic expression of FD, demonstrating a methodology that can be applied to a host of other genetic disorders to test the therapeutic potential of candidate molecules.
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Affiliation(s)
- Nathalie Boone
- Aix-Marseille Université, NICN, UMR 6184, Marseille, France
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Lee G, Studer L. Modelling familial dysautonomia in human induced pluripotent stem cells. Philos Trans R Soc Lond B Biol Sci 2011; 366:2286-96. [PMID: 21727134 DOI: 10.1098/rstb.2011.0026] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Induced pluripotent stem (iPS) cells have considerable promise as a novel tool for modelling human disease and for drug discovery. While the generation of disease-specific iPS cells has become routine, realizing the potential of iPS cells in disease modelling poses challenges at multiple fronts. Such challenges include selecting a suitable disease target, directing the fate of iPS cells into symptom-relevant cell populations, identifying disease-related phenotypes and showing reversibility of such phenotypes using genetic or pharmacological approaches. Finally, the system needs to be scalable for use in modern drug discovery. Here, we will discuss these points in the context of modelling familial dysautonomia (FD, Riley-Day syndrome, hereditary sensory and autonomic neuropathy III (HSAN-III)), a rare genetic disorder in the peripheral nervous system. We have demonstrated three disease-specific phenotypes in FD-iPS-derived cells that can be partially rescued by treating cells with the plant hormone kinetin. Here, we will discuss how to use FD-iPS cells further in high throughput drug discovery assays, in modelling disease severity and in performing mechanistic studies aimed at understanding disease pathogenesis. FD is a rare disease but represents an important testing ground for exploring the potential of iPS cell technology in modelling and treating human disease.
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Affiliation(s)
- Gabsang Lee
- Centre for Stem Cell Biology, Sloan-Kettering Institute for Cancer Research, 1275 York Avenue, New York, NY 10065, USA
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31
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Shetty RS, Gallagher CS, Chen YT, Hims MM, Mull J, Leyne M, Pickel J, Kwok D, Slaugenhaupt SA. Specific correction of a splice defect in brain by nutritional supplementation. Hum Mol Genet 2011; 20:4093-101. [PMID: 21821670 DOI: 10.1093/hmg/ddr333] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Recent studies emphasize the importance of mRNA splicing in human genetic disease, as 20-30% of all disease-causing mutations are predicted to result in mRNA splicing defects. The plasticity of the mRNA splicing reaction has made these mutations attractive candidates for the development of therapeutics. Familial dysautonomia (FD) is a severe neurodegenerative disorder, and all patients have an intronic IVS20+6T>C splice site mutation in the IKBKAP gene, which results in tissue-specific skipping of exon 20 and a corresponding reduction in ikappaB kinase complex associated protein (IKAP) levels. We created transgenic mouse lines using a human IKBKAP bacterial artificial chromosome (BAC) into which we inserted the IKBKAP splice mutation (FD BAC) and have shown that the transgenic mice exhibit the same tissue-specific aberrant splicing patterns as seen in FD patients. We have previously demonstrated that the plant cytokinin kinetin can significantly improve the production of wild-type IKBKAP transcripts in FD lymphoblast cell lines by improving exon inclusion. In this study, we tested the ability of kinetin to alter IKBKAP splicing in the transgenic mice carrying the FD BAC and show that it corrects IKBKAP splicing in all major tissues assayed, including the brain. The amount of wild-type IKBKAP mRNA and IKAP protein was significantly higher in the kinetin-treated mice. These exciting results prove that treatment of FD, as well as other mechanistically related splicing disorders, with kinetin holds great promise as a potential therapeutic aimed at increasing normal protein levels, which may, in turn, slow disease progression.
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Affiliation(s)
- Ranjit S Shetty
- Center for Human Genetic Research, Massachusetts General Hospital and Harvard Medical School, 185 Cambridge Street, CPZN-5254, Boston, MA 02114, USA
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Boone N, Loriod B, Bergon A, Sbai O, Formisano-Tréziny C, Gabert J, Khrestchatisky M, Nguyen C, Féron F, Axelrod FB, Ibrahim EC. Olfactory stem cells, a new cellular model for studying molecular mechanisms underlying familial dysautonomia. PLoS One 2010; 5:e15590. [PMID: 21187979 PMCID: PMC3004942 DOI: 10.1371/journal.pone.0015590] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2010] [Accepted: 11/13/2010] [Indexed: 12/29/2022] Open
Abstract
Background Familial dysautonomia (FD) is a hereditary neuropathy caused by mutations in the IKBKAP gene, the most common of which results in variable tissue-specific mRNA splicing with skipping of exon 20. Defective splicing is especially severe in nervous tissue, leading to incomplete development and progressive degeneration of sensory and autonomic neurons. The specificity of neuron loss in FD is poorly understood due to the lack of an appropriate model system. To better understand and modelize the molecular mechanisms of IKBKAP mRNA splicing, we collected human olfactory ecto-mesenchymal stem cells (hOE-MSC) from FD patients. hOE-MSCs have a pluripotent ability to differentiate into various cell lineages, including neurons and glial cells. Methodology/Principal Findings We confirmed IKBKAP mRNA alternative splicing in FD hOE-MSCs and identified 2 novel spliced isoforms also present in control cells. We observed a significant lower expression of both IKBKAP transcript and IKAP/hELP1 protein in FD cells resulting from the degradation of the transcript isoform skipping exon 20. We localized IKAP/hELP1 in different cell compartments, including the nucleus, which supports multiple roles for that protein. We also investigated cellular pathways altered in FD, at the genome-wide level, and confirmed that cell migration and cytoskeleton reorganization were among the processes altered in FD. Indeed, FD hOE-MSCs exhibit impaired migration compared to control cells. Moreover, we showed that kinetin improved exon 20 inclusion and restores a normal level of IKAP/hELP1 in FD hOE-MSCs. Furthermore, we were able to modify the IKBKAP splicing ratio in FD hOE-MSCs, increasing or reducing the WT (exon 20 inclusion):MU (exon 20 skipping) ratio respectively, either by producing free-floating spheres, or by inducing cells into neural differentiation. Conclusions/Significance hOE-MSCs isolated from FD patients represent a new approach for modeling FD to better understand genetic expression and possible therapeutic approaches. This model could also be applied to other neurological genetic diseases.
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Affiliation(s)
- Nathalie Boone
- NICN-CNRS UMR 6184, Université de la Méditerranée-Faculté de Médecine Nord, IFR Jean Roche, Marseille, France
| | | | | | - Oualid Sbai
- NICN-CNRS UMR 6184, Université de la Méditerranée-Faculté de Médecine Nord, IFR Jean Roche, Marseille, France
| | | | - Jean Gabert
- Plateforme Transcriptome, CRO2, Faculté de Médecine, Marseille, France
- Biochemistry and Molecular Biology, Hôpital Nord, AP-HM, Marseille, France
| | - Michel Khrestchatisky
- NICN-CNRS UMR 6184, Université de la Méditerranée-Faculté de Médecine Nord, IFR Jean Roche, Marseille, France
| | | | - François Féron
- NICN-CNRS UMR 6184, Université de la Méditerranée-Faculté de Médecine Nord, IFR Jean Roche, Marseille, France
| | - Felicia B. Axelrod
- Department of Pediatrics, New York University School of Medicine, New York, New York, United States of America
| | - El Chérif Ibrahim
- NICN-CNRS UMR 6184, Université de la Méditerranée-Faculté de Médecine Nord, IFR Jean Roche, Marseille, France
- * E-mail:
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Abstract
Ninety-four percent of human genes are discontinuous, such that segments expressed as mRNA are contained within exons and separated by intervening segments, called introns. Following transcription, genes are expressed as precursor mRNAs (pre-mRNAs), which are spliced co-transcriptionally, and the flanking exons are joined together to form a continuous mRNA. One advantage of this architecture is that it allows alternative splicing by differential use of exons to generate multiple mRNAs from individual genes. Regulatory elements located within introns and exons guide the splicing complex, the spliceosome, and auxiliary RNA binding proteins to the correct sites for intron removal and exon joining. Misregulation of splicing and alternative splicing can result from mutations in cis-regulatory elements within the affected gene or from mutations that affect the activities of trans-acting factors that are components of the splicing machinery. Mutations that affect splicing can cause disease directly or contribute to the susceptibility or severity of disease. An understanding of the role of splicing in disease expands potential opportunities for therapeutic intervention by either directly addressing the cause or by providing novel approaches to circumvent disease processes.
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Affiliation(s)
- Amanda J Ward
- Departments of Molecular and Cellular Biology and Pathology, Baylor College of Medicine, Houston, TX 77030, USA
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Zychlinski D, Erkelenz S, Melhorn V, Baum C, Schaal H, Bohne J. Limited complementarity between U1 snRNA and a retroviral 5' splice site permits its attenuation via RNA secondary structure. Nucleic Acids Res 2010; 37:7429-40. [PMID: 19854941 PMCID: PMC2794156 DOI: 10.1093/nar/gkp694] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Multiple types of regulation are used by cells and viruses to control alternative splicing. In murine leukemia virus, accessibility of the 5′ splice site (ss) is regulated by an upstream region, which can fold into a complex RNA stem–loop structure. The underlying sequence of the structure itself is negligible, since most of it could be functionally replaced by a simple heterologous RNA stem–loop preserving the wild-type splicing pattern. Increasing the RNA duplex formation between U1 snRNA and the 5′ss by a compensatory mutation in position +6 led to enhanced splicing. Interestingly, this mutation affects splicing only in the context of the secondary structure, arguing for a dynamic interplay between structure and primary 5′ss sequence. The reduced 5′ss accessibility could also be counteracted by recruiting a splicing enhancer domain via a modified MS2 phage coat protein to a single binding site at the tip of the simple RNA stem–loop. The mechanism of 5′ss attenuation was revealed using hyperstable U1 snRNA mutants, showing that restricted U1 snRNP access is the cause of retroviral alternative splicing.
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Affiliation(s)
- Daniela Zychlinski
- Institute for Virology, Hannover Medical School, 30625 Hannover, Germany
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Tazi J, Bakkour N, Stamm S. Alternative splicing and disease. BIOCHIMICA ET BIOPHYSICA ACTA 2009; 1792:14-26. [PMID: 18992329 PMCID: PMC5632948 DOI: 10.1016/j.bbadis.2008.09.017] [Citation(s) in RCA: 382] [Impact Index Per Article: 25.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2008] [Revised: 09/19/2008] [Accepted: 09/30/2008] [Indexed: 12/11/2022]
Abstract
Almost all protein-coding genes are spliced and their majority is alternatively spliced. Alternative splicing is a key element in eukaryotic gene expression that increases the coding capacity of the human genome and an increasing number of examples illustrates that the selection of wrong splice sites causes human disease. A fine-tuned balance of factors regulates splice site selection. Here, we discuss well-studied examples that show how a disturbance of this balance can cause human disease. The rapidly emerging knowledge of splicing regulation now allows the development of treatment options.
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Affiliation(s)
- Jamal Tazi
- University of Montpellier II, Institute of Molecular Genetics, Centre Nationale de Recherche Scientifique, 1919 Route de Mende, France
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36
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Hims MM, Shetty RS, Pickel J, Mull J, Leyne M, Liu L, Gusella JF, Slaugenhaupt SA. A humanized IKBKAP transgenic mouse models a tissue-specific human splicing defect. Genomics 2007; 90:389-96. [PMID: 17644305 PMCID: PMC1976430 DOI: 10.1016/j.ygeno.2007.05.012] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2006] [Revised: 05/27/2007] [Accepted: 05/30/2007] [Indexed: 12/18/2022]
Abstract
Familial dysautonomia (FD) is a severe hereditary sensory and autonomic neuropathy, and all patients with FD have a splice mutation in the IKBKAP gene. The FD splice mutation results in variable, tissue-specific skipping of exon 20 in IKBKAP mRNA, which leads to reduced IKAP protein levels. The development of therapies for FD will require suitable mouse models for preclinical studies. In this study, we report the generation and characterization of a mouse model carrying the complete human IKBKAP locus with the FD IVS20+6T-->C splice mutation. We show that the mutant IKBKAP transgene is misspliced in this model in a tissue-specific manner that replicates the pattern seen in FD patient tissues. Creation of this humanized mouse is the first step toward development of a complex phenotypic model of FD. These transgenic mice are an ideal model system for testing the effectiveness of therapeutic agents that target the missplicing defect. Last, these mice will permit direct studies of tissue-specific splicing and the identification of regulatory factors that play a role in complex gene expression.
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Affiliation(s)
- Matthew M. Hims
- Center for Human Genetic Research, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, USA
| | - Ranjit S. Shetty
- Center for Human Genetic Research, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, USA
| | - James Pickel
- National Institute of Mental Health, National Institutes of Health, Bethesda, MD 20892, USA
| | - James Mull
- Center for Human Genetic Research, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, USA
| | - Maire Leyne
- Center for Human Genetic Research, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, USA
| | - Lijuan Liu
- Center for Human Genetic Research, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, USA
| | - James F. Gusella
- Center for Human Genetic Research, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, USA
| | - Susan A. Slaugenhaupt
- Center for Human Genetic Research, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, USA
- *corresponding author: Susan A Slaugenhaupt, MGH Center for Human Genetic Research, 185 Cambridge Street, CPZN-5254, Boston , MA 02114, Tel: 617-643-3091; Fax: 617-726-5735;
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37
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Hims MM, Ibrahim EC, Leyne M, Mull J, Liu L, Lazaro C, Shetty RS, Gill S, Gusella JF, Reed R, Slaugenhaupt SA. Therapeutic potential and mechanism of kinetin as a treatment for the human splicing disease familial dysautonomia. J Mol Med (Berl) 2007; 85:149-61. [PMID: 17206408 DOI: 10.1007/s00109-006-0137-2] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2006] [Revised: 10/24/2006] [Accepted: 10/26/2006] [Indexed: 01/13/2023]
Abstract
Mutations that affect the splicing of pre-mRNA are a major cause of human disease. Familial dysautonomia (FD) is a recessive neurodegenerative disease caused by a T to C transition at base pair 6 of IKBKAP intron 20. This mutation results in variable tissue-specific skipping of exon 20. Previously, we reported that the plant cytokinin kinetin dramatically increases exon 20 inclusion in RNA isolated from cultured FD cells. The goal of the current study was to investigate the nature of the FD splicing defect and the mechanism by which kinetin improves exon inclusion, as such knowledge will facilitate the development of future therapeutics aimed at regulating mRNA splicing. In this study, we demonstrate that treatment of FD lymphoblast cell lines with kinetin increases IKBKAP mRNA and IKAP protein to normal levels. Using a series of minigene constructs, we show that deletion of a region at the end of IKBKAP exon 20 disrupts the ability of kinetin to improve exon inclusion, pinpointing a kinetin responsive sequence element. We next performed a screen of endogenously expressed genes with multiple isoforms resulting from exon skipping events and show that kinetin's ability to improve exon inclusion is not limited to IKBKAP. Lastly, we highlight the potential of kinetin for the treatment of other human splicing disorders by showing correction of a splicing defect in neurofibromatosis.
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Affiliation(s)
- Matthew M Hims
- Center for Human Genetic Research, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, USA
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