1
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Olthof AM, Schwoerer CF, Girardini KN, Weber AL, Doggett K, Mieruszynski S, Heath JK, Moore TE, Biran J, Kanadia RN. Taxonomy of introns and the evolution of minor introns. Nucleic Acids Res 2024:gkae550. [PMID: 38943346 DOI: 10.1093/nar/gkae550] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2023] [Revised: 06/05/2024] [Accepted: 06/13/2024] [Indexed: 07/01/2024] Open
Abstract
Classification of introns, which is crucial to understanding their evolution and splicing, has historically been binary and has resulted in the naming of major and minor introns that are spliced by their namesake spliceosome. However, a broad range of intron consensus sequences exist, leading us to here reclassify introns as minor, minor-like, hybrid, major-like, major and non-canonical introns in 263 species across six eukaryotic supergroups. Through intron orthology analysis, we discovered that minor-like introns are a transitory node for intron conversion across evolution. Despite close resemblance of their consensus sequences to minor introns, these introns possess an AG dinucleotide at the -1 and -2 position of the 5' splice site, a salient feature of major introns. Through combined analysis of CoLa-seq, CLIP-seq for major and minor spliceosome components, and RNAseq from samples in which the minor spliceosome is inhibited we found that minor-like introns are also an intermediate class from a splicing mechanism perspective. Importantly, this analysis has provided insight into the sequence elements that have evolved to make minor-like introns amenable to recognition by both minor and major spliceosome components. We hope that this revised intron classification provides a new framework to study intron evolution and splicing.
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Affiliation(s)
- Anouk M Olthof
- Physiology and Neurobiology Department, University of Connecticut, Storrs, CT, USA
| | - Charles F Schwoerer
- Physiology and Neurobiology Department, University of Connecticut, Storrs, CT, USA
| | - Kaitlin N Girardini
- Physiology and Neurobiology Department, University of Connecticut, Storrs, CT, USA
| | - Audrey L Weber
- Physiology and Neurobiology Department, University of Connecticut, Storrs, CT, USA
| | - Karen Doggett
- Walter and Eliza Hall Institute of Medical Research, Parkville, VIC 3052, Australia
| | - Stephen Mieruszynski
- Walter and Eliza Hall Institute of Medical Research, Parkville, VIC 3052, Australia
| | - Joan K Heath
- Walter and Eliza Hall Institute of Medical Research, Parkville, VIC 3052, Australia
| | - Timothy E Moore
- Statistical Consulting Services, Center for Open Research Resources & Equipment, University of Connecticut, Storrs, CT, USA
| | - Jakob Biran
- Department of Poultry and Aquaculture, Institute of Animal Science, Agricultural Research Organization, Rishon LeTsiyon, Israel
| | - Rahul N Kanadia
- Physiology and Neurobiology Department, University of Connecticut, Storrs, CT, USA
- Institute for Systems Genomics, University of Connecticut, Storrs, CT, USA
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2
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Schot R, Ferraro F, Geeven G, Diderich KEM, Barakat TS. Re-analysis of whole genome sequencing ends a diagnostic odyssey: Case report of an RNU4-2 related neurodevelopmental disorder. Clin Genet 2024. [PMID: 38859706 DOI: 10.1111/cge.14574] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2024] [Revised: 05/31/2024] [Accepted: 06/03/2024] [Indexed: 06/12/2024]
Abstract
Despite increasing knowledge of disease-causing genes in human genetics, approximately half of the individuals affected by neurodevelopmental disorders remain genetically undiagnosed. Part of this missing heritability might be caused by genetic variants outside of protein-coding genes, which are not routinely diagnostically investigated. A recent preprint identified de novo variants in the non-coding spliceosomal snRNA gene RNU4-2 as a cause of a frequent novel syndromic neurodevelopmental disorder. Here we mined 164 whole genome sequencing (WGS) trios from individuals with neurodevelopmental or multiple congenital anomaly disorders that received diagnostic genomic investigations at our clinic. We identify a recurrent de novo RNU4-2 variant (NR_003137.2(RNU4-2):n.64_65insT) in a 5-year-old girl with severe global developmental delay, hypotonia, microcephaly, and seizures that likely explains her phenotype, given that extensive previous genetic investigations failed to identify an alternative cause. We present detailed phenotyping of the individual obtained during a 5-year follow-up. This includes photographs showing recognizable facial features for this novel disorder, which might allow prioritizing other currently unexplained affected individuals sharing similar facial features for targeted investigations of RNU4-2. This case illustrates the power of re-analysis to solve previously unexplained cases even when a diagnostic genome remains negative.
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Affiliation(s)
- Rachel Schot
- Department of Clinical Genetics, Erasmus MC University Medical Center, Rotterdam, The Netherlands
- Discovery Unit, Department of Clinical Genetics, Erasmus MC University Medical Center, Rotterdam, The Netherlands
| | - Federico Ferraro
- Department of Clinical Genetics, Erasmus MC University Medical Center, Rotterdam, The Netherlands
| | - Geert Geeven
- Department of Clinical Genetics, Erasmus MC University Medical Center, Rotterdam, The Netherlands
| | - Karin E M Diderich
- Department of Clinical Genetics, Erasmus MC University Medical Center, Rotterdam, The Netherlands
| | - Tahsin Stefan Barakat
- Department of Clinical Genetics, Erasmus MC University Medical Center, Rotterdam, The Netherlands
- Discovery Unit, Department of Clinical Genetics, Erasmus MC University Medical Center, Rotterdam, The Netherlands
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3
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Gauthier LW, Gossez M, Malcus C, Viel S, Monneret G, Bordonné R, Pons L, Cabet S, Delous M, Mazoyer S, Putoux A, Edery P. B-cell immune deficiency in twin sisters expands the phenotype of MOPDI. Clin Genet 2024. [PMID: 38837402 DOI: 10.1111/cge.14571] [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: 02/26/2024] [Revised: 05/03/2024] [Accepted: 05/26/2024] [Indexed: 06/07/2024]
Abstract
Microcephalic osteodysplastic primordial dwarfism type I (MOPDI) is a very rare and severe autosomal recessive disorder characterized by marked intrauterine growth retardation, skeletal dysplasia, microcephaly and brain malformations. MOPDI is caused by biallelic mutations in RNU4ATAC, a non-coding gene involved in U12-type splicing of 1% of the introns in the genome, which are recognized by their specific splicing consensus sequences. Here, we describe a unique observation of immunodeficiency in twin sisters with mild MOPDI, who harbor a novel n.108_126del mutation, encompassing part of the U4atac snRNA 3' stem-loop and Sm protein binding site, and the previously reported n.111G>A mutation. Interestingly, both twin sisters show mild B-cell anomalies, including low naive B-cell counts and increased memory B-cell and plasmablasts counts, suggesting partial and transitory blockage of B-cell maturation and/or excessive activation of naive B-cells. Hence, the localization of a mutation in stem II of U4atac snRNA, as observed in another RNU4ATAC-opathy with immunodeficiency, that is, Roifman syndrome (RFMN), is not required for the occurrence of an immune deficiency. Finally, we emphasize the importance of considering immunodeficiency in MOPDI management to reduce the risk of serious infectious episodes.
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Affiliation(s)
- Lucas W Gauthier
- Department of Genetics, Clinical Genetics Unit, Centre de Référence Maladies Rares des Anomalies du Développement Sud-Est, Hospices Civils de Lyon, Université Claude Bernard Lyon 1, Bron, France
| | - Morgane Gossez
- CIRI, Centre International de Recherche en Infectiologie, Univ Lyon, Inserm U1111, Université Claude Bernard-Lyon 1, CNRS, UMR5308, ENS Lyon, Lyon, France
- Immunology Laboratory, Hospices Civils de Lyon, Edouard Herriot Hospital, Lyon, France
| | - Christophe Malcus
- Immunology Laboratory, Hospices Civils de Lyon, Edouard Herriot Hospital, Lyon, France
| | - Sébastien Viel
- Plateforme de Biothérapies et de production de MTI, Hôpital Edouard Herriot, Hospices Civils de Lyon, Lyon, France
| | - Guillaume Monneret
- Immunology Laboratory, Hospices Civils de Lyon, Edouard Herriot Hospital, Lyon, France
- Equipe d'Accueil 7426, Pathophysiology of Injury-Induced Immunosuppression, Université Claude Bernard Lyon 1, Hospices Civils de Lyon - bioMérieux, Hôpital Edouard Herriot, Lyon, France
| | - Remy Bordonné
- Institut de Génétique Moléculaire de Montpellier, University of Montpellier, CNRS UMR5535, Montpellier, France
| | - Linda Pons
- Unité Fonctionnelle de Cytogénétique, Laboratoire de Biologie Médicale, Centre hospitalier de Valence, Valence, France
| | - Sara Cabet
- Pediatric and Fetal Imaging Department, Femme-Mère-Enfant Hospital, Hospices Civils de Lyon, Claude Bernard Lyon 1 University, Lyon, France
- Institut NeuroMyoGène, CNRS UMR5292, INSERM U1028, Claude Bernard Lyon 1 University, Lyon, France
| | - Marion Delous
- Université Claude Bernard Lyon 1, INSERM, CNRS, Centre de Recherche en Neurosciences de Lyon CRNL U1028 UMR5292, Genetics of Neurodevelopment Team (GENDEV), Bron, France
| | - Sylvie Mazoyer
- Université Claude Bernard Lyon 1, INSERM, CNRS, Centre de Recherche en Neurosciences de Lyon CRNL U1028 UMR5292, Genetics of Neurodevelopment Team (GENDEV), Bron, France
| | - Audrey Putoux
- Department of Genetics, Clinical Genetics Unit, Centre de Référence Maladies Rares des Anomalies du Développement Sud-Est, Hospices Civils de Lyon, Université Claude Bernard Lyon 1, Bron, France
- Université Claude Bernard Lyon 1, INSERM, CNRS, Centre de Recherche en Neurosciences de Lyon CRNL U1028 UMR5292, Genetics of Neurodevelopment Team (GENDEV), Bron, France
| | - Patrick Edery
- Department of Genetics, Clinical Genetics Unit, Centre de Référence Maladies Rares des Anomalies du Développement Sud-Est, Hospices Civils de Lyon, Université Claude Bernard Lyon 1, Bron, France
- Université Claude Bernard Lyon 1, INSERM, CNRS, Centre de Recherche en Neurosciences de Lyon CRNL U1028 UMR5292, Genetics of Neurodevelopment Team (GENDEV), Bron, France
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4
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Nishimura K, Saika W, Inoue D. Minor introns impact on hematopoietic malignancies. Exp Hematol 2024; 132:104173. [PMID: 38309573 DOI: 10.1016/j.exphem.2024.104173] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2023] [Revised: 12/25/2023] [Accepted: 01/03/2024] [Indexed: 02/05/2024]
Abstract
In the intricate orchestration of the central dogma, pre-mRNA splicing plays a crucial role in the post-transcriptional process that transforms DNA into mature mRNA. Widely acknowledged as a pivotal RNA processing step, it significantly influences gene expression and alters the functionality of gene product proteins. Although U2-dependent spliceosomes efficiently manage the removal of over 99% of introns, a distinct subset of essential genes undergo splicing with a different intron type, denoted as minor introns, using U12-dependent spliceosomes. Mutations in spliceosome component genes are now recognized as prevalent genetic abnormalities in cancer patients, especially those with hematologic malignancies. Despite the relative rarity of minor introns, genes containing them are evolutionarily conserved and play crucial roles in functions such as the RAS-MAPK pathway. Disruptions in U12-type minor intron splicing caused by mutations in snRNA or its regulatory components significantly contribute to cancer progression. Notably, recurrent mutations associated with myelodysplastic syndrome (MDS) in the minor spliceosome component ZRSR2 underscore its significance. Examination of ZRSR2-mutated MDS cells has revealed that only a subset of minor spliceosome-dependent genes, such as LZTR1, consistently exhibit missplicing. Recent technological advancements have uncovered insights into minor introns, raising inquiries beyond current understanding. This review comprehensively explores the importance of minor intron regulation, the molecular implications of minor (U12-type) spliceosomal mutations and cis-regulatory regions, and the evolutionary progress of studies on minor, aiming to provide a sophisticated understanding of their intricate role in cancer biology.
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Affiliation(s)
- Koutarou Nishimura
- Department of Hematology-Oncology, Institute of Biomedical Research and Innovation, Foundation for Biomedical Research and Innovation at Kobe, Kobe, Hyogo, Japan.
| | - Wataru Saika
- Department of Hematology-Oncology, Institute of Biomedical Research and Innovation, Foundation for Biomedical Research and Innovation at Kobe, Kobe, Hyogo, Japan; Department of Hematology, Shiga University of Medical Science, Ōtsu, Shiga, Japan
| | - Daichi Inoue
- Department of Hematology-Oncology, Institute of Biomedical Research and Innovation, Foundation for Biomedical Research and Innovation at Kobe, Kobe, Hyogo, Japan.
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5
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Kwon YS, Jin SW, Song H. Global analysis of binding sites of U2AF1 and ZRSR2 reveals RNA elements required for mutually exclusive splicing by the U2- and U12-type spliceosome. Nucleic Acids Res 2024; 52:1420-1434. [PMID: 38088204 PMCID: PMC10853781 DOI: 10.1093/nar/gkad1180] [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: 06/14/2022] [Revised: 11/18/2023] [Accepted: 12/05/2023] [Indexed: 02/10/2024] Open
Abstract
Recurring mutations in genes encoding 3' splice-site recognition proteins, U2AF1 and ZRSR2 are associated with human cancers. Here, we determined binding sites of the proteins to reveal that U2-type and U12-type splice sites are recognized by U2AF1 and ZRSR2, respectively. However, some sites are spliced by both the U2-type and U12-type spliceosomes, indicating that well-conserved consensus motifs in some U12-type introns could be recognized by the U2-type spliceosome. Nucleotides flanking splice sites of U12-type introns are different from those flanking U2-type introns. Remarkably, the AG dinucleotide at the positions -1 and -2 of 5' splice sites of U12-type introns with GT-AG termini is not present. AG next to 5' splice site introduced by a single nucleotide substitution at the -2 position could convert a U12-type splice site to a U2-type site. The class switch of introns by a single mutation and the bias against G at the -1 position of U12-type 5' splice site support the notion that the identities of nucleotides in exonic regions adjacent to splice sites are fine-tuned to avoid recognition by the U2-type spliceosome. These findings may shed light on the mechanism of selectivity in U12-type intron splicing and the mutations that affect splicing.
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Affiliation(s)
- Young-Soo Kwon
- Department of Integrative Bioscience & Biotechnology, Sejong University, Seoul 05006, Korea
| | - Sang Woo Jin
- BK21 Graduate Program, Department of Biomedical Sciences, College of Medicine, Korea University Guro Hospital, Seoul 08308, Korea
| | - Hoseok Song
- BK21 Graduate Program, Department of Biomedical Sciences, College of Medicine, Korea University Guro Hospital, Seoul 08308, Korea
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6
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Li B, Liu S, Zheng W, Liu A, Yu P, Wu D, Zhou J, Zhang P, Liu C, Lin Q, Ye J, He S, Huang Q, Zhou H, Chen J, Qu L, Yang J. RIP-PEN-seq identifies a class of kink-turn RNAs as splicing regulators. Nat Biotechnol 2024; 42:119-131. [PMID: 37037902 DOI: 10.1038/s41587-023-01749-0] [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: 08/02/2022] [Accepted: 03/13/2023] [Indexed: 04/12/2023]
Abstract
A kink-turn (K-turn) is a three-dimensional RNA structure that exists in all three primary phylogenetic domains. In this study, we developed the RIP-PEN-seq method to identify the full-length sequences of RNAs bound by the K-turn binding protein 15.5K and discovered a previously uncharacterized class of RNAs with backward K-turn motifs (bktRNAs) in humans and mice. All bktRNAs share two consensus sequence motifs at their fixed terminal position and have complex folding properties, expression and evolution patterns. We found that a highly conserved bktRNA1 guides the methyltransferase fibrillarin to install RNA methylation of U12 small nuclear RNA in humans. Depletion of bktRNA1 causes global splicing dysregulation of U12-type introns by impairing the recruitment of ZCRB1 to the minor spliceosome. Most bktRNAs regulate the splicing of local introns by interacting with the 15.5K protein. Taken together, our findings characterize a class of small RNAs and uncover another layer of gene expression regulation that involves crosstalk among bktRNAs, RNA splicing and RNA methylation.
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Affiliation(s)
- Bin Li
- MOE Key Laboratory of Gene Function and Regulation, State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Shurong Liu
- MOE Key Laboratory of Gene Function and Regulation, State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Wujian Zheng
- MOE Key Laboratory of Gene Function and Regulation, State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
- The Fifth Affiliated Hospital, Sun Yat-sen University, Zhuhai, China
| | - Anrui Liu
- MOE Key Laboratory of Gene Function and Regulation, State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
- The Fifth Affiliated Hospital, Sun Yat-sen University, Zhuhai, China
| | - Peng Yu
- MOE Key Laboratory of Gene Function and Regulation, State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Di Wu
- MOE Key Laboratory of Gene Function and Regulation, State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
- The Fifth Affiliated Hospital, Sun Yat-sen University, Zhuhai, China
| | - Jie Zhou
- MOE Key Laboratory of Gene Function and Regulation, State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
- The Fifth Affiliated Hospital, Sun Yat-sen University, Zhuhai, China
| | - Ping Zhang
- MOE Key Laboratory of Gene Function and Regulation, State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Chang Liu
- MOE Key Laboratory of Gene Function and Regulation, State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Qiao Lin
- MOE Key Laboratory of Gene Function and Regulation, State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
- The Fifth Affiliated Hospital, Sun Yat-sen University, Zhuhai, China
| | - Jiayi Ye
- MOE Key Laboratory of Gene Function and Regulation, State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
- The Fifth Affiliated Hospital, Sun Yat-sen University, Zhuhai, China
| | - Simeng He
- The Fifth Affiliated Hospital, Sun Yat-sen University, Zhuhai, China
| | - Qiaojuan Huang
- MOE Key Laboratory of Gene Function and Regulation, State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Hui Zhou
- MOE Key Laboratory of Gene Function and Regulation, State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, China
| | - Jianjun Chen
- Department of Systems Biology, Beckman Research Institute of City of Hope, Monrovia, CA, USA
| | - Lianghu Qu
- MOE Key Laboratory of Gene Function and Regulation, State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, China.
| | - Jianhua Yang
- MOE Key Laboratory of Gene Function and Regulation, State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, China.
- The Fifth Affiliated Hospital, Sun Yat-sen University, Zhuhai, China.
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7
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Tabib A, Richmond CM, McGaughran J. Delineating the phenotype of RNU4ATAC-related spliceosomopathy. Am J Med Genet A 2023; 191:1094-1100. [PMID: 36622817 DOI: 10.1002/ajmg.a.63110] [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: 11/09/2022] [Revised: 12/19/2022] [Accepted: 12/22/2022] [Indexed: 01/10/2023]
Abstract
Biallelic pathogenic variants in RNU4ATAC cause microcephalic osteodysplastic primordial dwarfism type I (MOPD1), Roifman syndrome (RS) and Lowry-Wood syndrome (LWS). These conditions demonstrate significant phenotypic heterogeneity yet have overlapping features. Although historically described as discrete conditions they appear to represent a phenotypic spectrum with clinical features not always aligning with diagnostic categories. Clinical variability and ambiguity in diagnostic criteria exist among each disorder. Here we report an individual with a novel genotype and phenotype spanning all three disorders, expanding the phenotypic spectrum of RNU4ATAC-related spliceosomeopathies.
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Affiliation(s)
- Amanda Tabib
- Paediatrics, John Hunter Children's Hospital, Newcastle, New South Wales, Australia
| | - Christopher M Richmond
- Genetic Health QLD, Royal Brisbane & Women's Hospital, Herston, Queensland, Australia.,School of Medicine, Griffith University, Southport, Queensland, Australia
| | - Julie McGaughran
- Genetic Health QLD, Royal Brisbane & Women's Hospital, Herston, Queensland, Australia.,Faculty of Medicine, University of Queensland, St. Lucia, Queensland, Australia
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8
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Khatri D, Putoux A, Cologne A, Kaltenbach S, Besson A, Bertiaux E, Guguin J, Fendler A, Dupont MA, Benoit-Pilven C, Qebibo L, Ahmed-Elie S, Audebert-Bellanger S, Blanc P, Rambaud T, Castelle M, Cornen G, Grotto S, Guët A, Guibaud L, Michot C, Odent S, Ruaud L, Sacaze E, Hamel V, Bordonné R, Leutenegger AL, Edery P, Burglen L, Attié-Bitach T, Mazoyer S, Delous M. Deficiency of the minor spliceosome component U4atac snRNA secondarily results in ciliary defects in human and zebrafish. Proc Natl Acad Sci U S A 2023; 120:e2102569120. [PMID: 36802443 PMCID: PMC9992838 DOI: 10.1073/pnas.2102569120] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Accepted: 12/12/2022] [Indexed: 02/23/2023] Open
Abstract
In the human genome, about 750 genes contain one intron excised by the minor spliceosome. This spliceosome comprises its own set of snRNAs, among which U4atac. Its noncoding gene, RNU4ATAC, has been found mutated in Taybi-Linder (TALS/microcephalic osteodysplastic primordial dwarfism type 1), Roifman (RFMN), and Lowry-Wood (LWS) syndromes. These rare developmental disorders, whose physiopathological mechanisms remain unsolved, associate ante- and post-natal growth retardation, microcephaly, skeletal dysplasia, intellectual disability, retinal dystrophy, and immunodeficiency. Here, we report bi-allelic RNU4ATAC mutations in five patients presenting with traits suggestive of the Joubert syndrome (JBTS), a well-characterized ciliopathy. These patients also present with traits typical of TALS/RFMN/LWS, thus widening the clinical spectrum of RNU4ATAC-associated disorders and indicating ciliary dysfunction as a mechanism downstream of minor splicing defects. Intriguingly, all five patients carry the n.16G>A mutation, in the Stem II domain, either at the homozygous or compound heterozygous state. A gene ontology term enrichment analysis on minor intron-containing genes reveals that the cilium assembly process is over-represented, with no less than 86 cilium-related genes containing at least one minor intron, among which there are 23 ciliopathy-related genes. The link between RNU4ATAC mutations and ciliopathy traits is supported by alterations of primary cilium function in TALS and JBTS-like patient fibroblasts, as well as by u4atac zebrafish model, which exhibits ciliopathy-related phenotypes and ciliary defects. These phenotypes could be rescued by WT but not by pathogenic variants-carrying human U4atac. Altogether, our data indicate that alteration of cilium biogenesis is part of the physiopathological mechanisms of TALS/RFMN/LWS, secondarily to defects of minor intron splicing.
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Affiliation(s)
- Deepak Khatri
- Université Claude Bernard Lyon 1, INSERM, CNRS, Centre de Recherche en Neurosciences de Lyon CRNL U1028 UMR5292,Genetics of Neurodevelopment Team, 69500Bron, France
| | - Audrey Putoux
- Université Claude Bernard Lyon 1, INSERM, CNRS, Centre de Recherche en Neurosciences de Lyon CRNL U1028 UMR5292,Genetics of Neurodevelopment Team, 69500Bron, France
- Department of Genetics, Clinical Genetics Unit, Centre de Référence Maladies Rares des Anomalies du Développement, Hospices Civils de Lyon, Université Claude Bernard Lyon 1, 69500Bron, France
| | - Audric Cologne
- Université Claude Bernard Lyon 1, INSERM, CNRS, Centre de Recherche en Neurosciences de Lyon CRNL U1028 UMR5292,Genetics of Neurodevelopment Team, 69500Bron, France
- Institut national de recherche en sciences et technologies du numérique Erable, Laboratoire de Biométrie et Biologie Evolutive, UMR5558 CNRS, Université Claude Bernard Lyon 1, 69622Villeurbanne, France
| | - Sophie Kaltenbach
- Department of Histology Embryology and Cytogenetics, Assistance Publique - Hôpitaux de Paris, Necker-Enfants Malades Hospital, University of Paris, 75015Paris, France
| | - Alicia Besson
- Université Claude Bernard Lyon 1, INSERM, CNRS, Centre de Recherche en Neurosciences de Lyon CRNL U1028 UMR5292,Genetics of Neurodevelopment Team, 69500Bron, France
| | - Eloïse Bertiaux
- Department of Cell Biology, Sciences III, University of Geneva, 1211-Geneva, Switzerland
| | - Justine Guguin
- Université Claude Bernard Lyon 1, INSERM, CNRS, Centre de Recherche en Neurosciences de Lyon CRNL U1028 UMR5292,Genetics of Neurodevelopment Team, 69500Bron, France
| | - Adèle Fendler
- Université Claude Bernard Lyon 1, INSERM, CNRS, Centre de Recherche en Neurosciences de Lyon CRNL U1028 UMR5292,Genetics of Neurodevelopment Team, 69500Bron, France
| | - Marie A. Dupont
- Laboratory of hereditary kidney diseases, Imagine Institute, U1163 INSERM, University of Paris, 75015Paris, France
| | - Clara Benoit-Pilven
- Université Claude Bernard Lyon 1, INSERM, CNRS, Centre de Recherche en Neurosciences de Lyon CRNL U1028 UMR5292,Genetics of Neurodevelopment Team, 69500Bron, France
- Institut national de recherche en sciences et technologies du numérique Erable, Laboratoire de Biométrie et Biologie Evolutive, UMR5558 CNRS, Université Claude Bernard Lyon 1, 69622Villeurbanne, France
| | - Leila Qebibo
- Département de Génétique, Centre de Référence des Malformations et Maladies Congénitales du Cervelet, Assistance Publique - Hôpitaux de Paris, Sorbonne University, Trousseau Hospital, 75012Paris, France
| | - Samira Ahmed-Elie
- Département de Génétique, Centre de Référence des Malformations et Maladies Congénitales du Cervelet, Assistance Publique - Hôpitaux de Paris, Sorbonne University, Trousseau Hospital, 75012Paris, France
| | - Séverine Audebert-Bellanger
- Department of Genetics, Clinical Genetics Unit, Centre de Compétence Anomalies du Développement et Syndromes Polymalformatifs, Centre Hospitalier Universitaire Morvan, 29200Brest, France
| | | | | | - Martin Castelle
- Hematology-Immunology Unit, Assistance Publique - Hôpitaux de Paris, Necker-Enfants Malades Hospital, 75015Paris, France
| | - Gaëlle Cornen
- Pediatric service, Centre Hospitalier Morlaix, 29600Morlaix, France
| | - Sarah Grotto
- Clinical Genetics Unit, Maternité Port-Royal, Assistance Publique - Hôpitaux de Paris, Cochin Broca Hôtel-Dieu Hospitals75014Paris, France
| | - Agnès Guët
- Neonatal and Pediatric Units, Louis-Mourier Hospital, 92700Colombes, France
| | - Laurent Guibaud
- Pediatric and Fetal Imaging, Hospices Civils de Lyon, Université Claude Bernard Lyon 1, 69500Bron, France
| | - Caroline Michot
- Clinical Genetics Department, Centre de Référence Maladies Rares–Maladies Osseuses Constitutionnelles, Assistance Publique - Hôpitaux de Paris, Necker-Enfants Malades Hospital, 75015Paris, France
- Developmental Brain Disorders Laboratory, Imagine Institute, U1163 INSERM, University of Paris, 75015Paris, France
| | - Sylvie Odent
- Service de Génétique Clinique, Centre Hospitalier Universitaire Rennes, Centre de référence Anomalies du développement et syndromes malformatifs, Univ Rennes, CNRS, INSERM, Institut de Génétique et Développement de Rennes UMR 6290/ Equipe de Recherche Labellisée 1305, 35000Rennes, France
| | - Lyse Ruaud
- NeuroDiderot, UMR1141, University of Paris, 75019Paris, France
- Departement of Genetics, Assistance Publique - Hôpitaux de Paris, Robert Debré Hospital, 75019Paris, France
| | - Elise Sacaze
- Pediatric Service, Centre Hospitalier Régional Universitaire Brest, 29200Brest, France
| | - Virginie Hamel
- Department of Cell Biology, Sciences III, University of Geneva, 1211-Geneva, Switzerland
| | - Rémy Bordonné
- Institute of Molecular Genetics of Montpellier, UMR5535 CNRS, University of Montpellier, 34000Montpellier, France
| | | | - Patrick Edery
- Université Claude Bernard Lyon 1, INSERM, CNRS, Centre de Recherche en Neurosciences de Lyon CRNL U1028 UMR5292,Genetics of Neurodevelopment Team, 69500Bron, France
- Department of Genetics, Clinical Genetics Unit, Centre de Référence Maladies Rares des Anomalies du Développement, Hospices Civils de Lyon, Université Claude Bernard Lyon 1, 69500Bron, France
| | - Lydie Burglen
- Département de Génétique, Centre de Référence des Malformations et Maladies Congénitales du Cervelet, Assistance Publique - Hôpitaux de Paris, Sorbonne University, Trousseau Hospital, 75012Paris, France
- Developmental Brain Disorders Laboratory, Imagine Institute, U1163 INSERM, University of Paris, 75015Paris, France
| | - Tania Attié-Bitach
- Department of Histology Embryology and Cytogenetics, Assistance Publique - Hôpitaux de Paris, Necker-Enfants Malades Hospital, University of Paris, 75015Paris, France
- Developmental Brain Disorders Laboratory, Imagine Institute, U1163 INSERM, University of Paris, 75015Paris, France
| | - Sylvie Mazoyer
- Université Claude Bernard Lyon 1, INSERM, CNRS, Centre de Recherche en Neurosciences de Lyon CRNL U1028 UMR5292,Genetics of Neurodevelopment Team, 69500Bron, France
| | - Marion Delous
- Université Claude Bernard Lyon 1, INSERM, CNRS, Centre de Recherche en Neurosciences de Lyon CRNL U1028 UMR5292,Genetics of Neurodevelopment Team, 69500Bron, France
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9
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Almentina Ramos Shidi F, Cologne A, Delous M, Besson A, Putoux A, Leutenegger AL, Lacroix V, Edery P, Mazoyer S, Bordonné R. Mutations in the non-coding RNU4ATAC gene affect the homeostasis and function of the Integrator complex. Nucleic Acids Res 2022; 51:712-727. [PMID: 36537210 PMCID: PMC9881141 DOI: 10.1093/nar/gkac1182] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Revised: 11/17/2022] [Accepted: 11/28/2022] [Indexed: 12/24/2022] Open
Abstract
Various genetic diseases associated with microcephaly and developmental defects are due to pathogenic variants in the U4atac small nuclear RNA (snRNA), a component of the minor spliceosome essential for the removal of U12-type introns from eukaryotic mRNAs. While it has been shown that a few RNU4ATAC mutations result in impaired binding of essential protein components, the molecular defects of the vast majority of variants are still unknown. Here, we used lymphoblastoid cells derived from RNU4ATAC compound heterozygous (g.108_126del;g.111G>A) twin patients with MOPD1 phenotypes to analyze the molecular consequences of the mutations on small nuclear ribonucleoproteins (snRNPs) formation and on splicing. We found that the U4atac108_126del mutant is unstable and that the U4atac111G>A mutant as well as the minor di- and tri-snRNPs are present at reduced levels. Our results also reveal the existence of 3'-extended snRNA transcripts in patients' cells. Moreover, we show that the mutant cells have alterations in splicing of INTS7 and INTS10 minor introns, contain lower levels of the INTS7 and INTS10 proteins and display changes in the assembly of Integrator subunits. Altogether, our results show that compound heterozygous g.108_126del;g.111G>A mutations induce splicing defects and affect the homeostasis and function of the Integrator complex.
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Affiliation(s)
- Fatimat Almentina Ramos Shidi
- Institut de Génétique Moléculaire de Montpellier, University of Montpellier, CNRS UMR5535, 34293 Montpellier, France
| | - Audric Cologne
- INRIA Erable, CNRS LBBE UMR 5558, University Lyon 1, University of Lyon, 69622 Villeurbanne, France
| | - Marion Delous
- Université Claude Bernard Lyon 1, INSERM, CNRS, Centre de Recherche en Neurosciences de Lyon U1028 UMR5292, GENDEV, 69500 Bron, France
| | - Alicia Besson
- Université Claude Bernard Lyon 1, INSERM, CNRS, Centre de Recherche en Neurosciences de Lyon U1028 UMR5292, GENDEV, 69500 Bron, France
| | - Audrey Putoux
- Université Claude Bernard Lyon 1, INSERM, CNRS, Centre de Recherche en Neurosciences de Lyon U1028 UMR5292, GENDEV, 69500 Bron, France,Clinical Genetics Unit, Department of Genetics, Centre de Référence Anomalies du Développement et Syndromes Polymalformatifs, Hospices Civils de Lyon, University Lyon 1, Bron, France
| | | | - Vincent Lacroix
- INRIA Erable, CNRS LBBE UMR 5558, University Lyon 1, University of Lyon, 69622 Villeurbanne, France
| | - Patrick Edery
- Université Claude Bernard Lyon 1, INSERM, CNRS, Centre de Recherche en Neurosciences de Lyon U1028 UMR5292, GENDEV, 69500 Bron, France,Clinical Genetics Unit, Department of Genetics, Centre de Référence Anomalies du Développement et Syndromes Polymalformatifs, Hospices Civils de Lyon, University Lyon 1, Bron, France
| | - Sylvie Mazoyer
- Université Claude Bernard Lyon 1, INSERM, CNRS, Centre de Recherche en Neurosciences de Lyon U1028 UMR5292, GENDEV, 69500 Bron, France
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10
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Olthof AM, White AK, Kanadia RN. The emerging significance of splicing in vertebrate development. Development 2022; 149:dev200373. [PMID: 36178052 PMCID: PMC9641660 DOI: 10.1242/dev.200373] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Splicing is a crucial regulatory node of gene expression that has been leveraged to expand the proteome from a limited number of genes. Indeed, the vast increase in intron number that accompanied vertebrate emergence might have aided the evolution of developmental and organismal complexity. Here, we review how animal models for core spliceosome components have provided insights into the role of splicing in vertebrate development, with a specific focus on neuronal, neural crest and skeletal development. To this end, we also discuss relevant spliceosomopathies, which are developmental disorders linked to mutations in spliceosome subunits. Finally, we discuss potential mechanisms that could underlie the tissue-specific phenotypes often observed upon spliceosome inhibition and identify gaps in our knowledge that, we hope, will inspire further research.
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Affiliation(s)
- Anouk M. Olthof
- Physiology and Neurobiology Department, University of Connecticut, Storrs, CT 06269, USA
- Department of Cellular and Molecular Medicine, University of Copenhagen, Copenhagen 2200, Denmark
| | - Alisa K. White
- Physiology and Neurobiology Department, University of Connecticut, Storrs, CT 06269, USA
| | - Rahul N. Kanadia
- Physiology and Neurobiology Department, University of Connecticut, Storrs, CT 06269, USA
- Institute for Systems Genomics, University of Connecticut, Storrs, CT 06269, USA
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11
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Jacquier V, Prévot M, Gostan T, Bordonné R, Benkhelifa-Ziyyat S, Barkats M, Soret J. Splicing efficiency of minor introns in a mouse model of SMA predominantly depends on their branchpoint sequence and can involve the contribution of major spliceosome components. RNA (NEW YORK, N.Y.) 2022; 28:303-319. [PMID: 34893560 PMCID: PMC8848931 DOI: 10.1261/rna.078329.120] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Accepted: 11/22/2021] [Indexed: 06/14/2023]
Abstract
Spinal muscular atrophy (SMA) is a devastating neurodegenerative disease caused by reduced amounts of the ubiquitously expressed Survival of Motor Neuron (SMN) protein. In agreement with its crucial role in the biogenesis of spliceosomal snRNPs, SMN-deficiency is correlated to numerous splicing alterations in patient cells and various tissues of SMA mouse models. Among the snRNPs whose assembly is impacted by SMN-deficiency, those involved in the minor spliceosome are particularly affected. Importantly, splicing of several, but not all U12-dependent introns has been shown to be affected in different SMA models. Here, we have investigated the molecular determinants of this differential splicing in spinal cords from SMA mice. We show that the branchpoint sequence (BPS) is a key element controlling splicing efficiency of minor introns. Unexpectedly, splicing of several minor introns with suboptimal BPS is not affected in SMA mice. Using in vitro splicing experiments and oligonucleotides targeting minor or major snRNAs, we show for the first time that splicing of these introns involves both the minor and major machineries. Our results strongly suggest that splicing of a subset of minor introns is not affected in SMA mice because components of the major spliceosome compensate for the loss of minor splicing activity.
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Affiliation(s)
- Valentin Jacquier
- Institut de Génétique Moléculaire de Montpellier, Univ Montpellier, CNRS, Montpellier 34293, France
| | - Manon Prévot
- Institut de Génétique Moléculaire de Montpellier, Univ Montpellier, CNRS, Montpellier 34293, France
| | - Thierry Gostan
- Institut de Génétique Moléculaire de Montpellier, Univ Montpellier, CNRS, Montpellier 34293, France
| | - Rémy Bordonné
- Institut de Génétique Moléculaire de Montpellier, Univ Montpellier, CNRS, Montpellier 34293, France
| | - Sofia Benkhelifa-Ziyyat
- Centre de Recherche en Myologie (CRM), Institut de Myologie, Sorbonne Universités, UPMC Univ Paris 06, Inserm UMRS974, GH Pitié Salpêtrière, Paris 75013, France
| | - Martine Barkats
- Centre de Recherche en Myologie (CRM), Institut de Myologie, Sorbonne Universités, UPMC Univ Paris 06, Inserm UMRS974, GH Pitié Salpêtrière, Paris 75013, France
| | - Johann Soret
- Institut de Génétique Moléculaire de Montpellier, Univ Montpellier, CNRS, Montpellier 34293, France
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12
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Ibáñez-Costa A, Perez-Sanchez C, Patiño-Trives AM, Luque-Tevar M, Font P, Arias de la Rosa I, Roman-Rodriguez C, Abalos-Aguilera MC, Conde C, Gonzalez A, Pedraza-Arevalo S, Del Rio-Moreno M, Blazquez-Encinas R, Segui P, Calvo J, Ortega Castro R, Escudero-Contreras A, Barbarroja N, Aguirre MA, Castaño JP, Luque RM, Collantes-Estevez E, Lopez-Pedrera C. Splicing machinery is impaired in rheumatoid arthritis, associated with disease activity and modulated by anti-TNF therapy. Ann Rheum Dis 2021; 81:56-67. [PMID: 34625402 PMCID: PMC8762032 DOI: 10.1136/annrheumdis-2021-220308] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Accepted: 08/18/2021] [Indexed: 12/29/2022]
Abstract
OBJECTIVES To characterise splicing machinery (SM) alterations in leucocytes of patients with rheumatoid arthritis (RA), and to assess its influence on their clinical profile and therapeutic response. METHODS Leucocyte subtypes from 129 patients with RA and 29 healthy donors (HD) were purified, and 45 selected SM elements (SME) were evaluated by quantitative PCR-array based on microfluidic technology (Fluidigm). Modulation by anti-tumour necrosis factor (TNF) therapy and underlying regulatory mechanisms were assessed. RESULTS An altered expression of several SME was found in RA leucocytes. Eight elements (SNRNP70, SNRNP200, U2AF2, RNU4ATAC, RBM3, RBM17, KHDRBS1 and SRSF10) were equally altered in all leucocytes subtypes. Logistic regressions revealed that this signature might: discriminate RA and HD, and anti-citrullinated protein antibodies (ACPAs) positivity; classify high-disease activity (disease activity score-28 (DAS28) >5.1); recognise radiological involvement; and identify patients showing atheroma plaques. Furthermore, this signature was altered in RA synovial fluid and ankle joints of K/BxN-arthritic mice. An available RNA-seq data set enabled to validate data and identified distinctive splicing events and splicing variants among patients with RA expressing high and low SME levels. 3 and 6 months anti-TNF therapy reversed their expression in parallel to the reduction of the inflammatory profile. In vitro, ACPAs modulated SME, at least partially, by Fc Receptor (FcR)-dependent mechanisms. Key inflammatory cytokines further altered SME. Lastly, induced SNRNP70-overexpression and KHDRBS1-overexpression reversed inflammation in lymphocytes, NETosis in neutrophils and adhesion in RA monocytes and influenced activity of RA synovial fibroblasts. CONCLUSIONS Overall, we have characterised for the first time a signature comprising eight dysregulated SME in RA leucocytes from both peripheral blood and synovial fluid, linked to disease pathophysiology, modulated by ACPAs and reversed by anti-TNF therapy.
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Affiliation(s)
- Alejandro Ibáñez-Costa
- Rheumatology Service, Maimonides Institute of Biomedical Research of Cordoba (IMIBIC),Reina Sofia University Hospital, University of Córdoba, Cordoba, Spain
| | - Carlos Perez-Sanchez
- Rheumatology Service, Maimonides Institute of Biomedical Research of Cordoba (IMIBIC),Reina Sofia University Hospital, University of Córdoba, Cordoba, Spain
| | - Alejandra María Patiño-Trives
- Rheumatology Service, Maimonides Institute of Biomedical Research of Cordoba (IMIBIC),Reina Sofia University Hospital, University of Córdoba, Cordoba, Spain
| | - Maria Luque-Tevar
- Rheumatology Service, Maimonides Institute of Biomedical Research of Cordoba (IMIBIC),Reina Sofia University Hospital, University of Córdoba, Cordoba, Spain
| | - Pilar Font
- Rheumatology Service, Maimonides Institute of Biomedical Research of Cordoba (IMIBIC),Reina Sofia University Hospital, University of Córdoba, Cordoba, Spain
| | - Ivan Arias de la Rosa
- Rheumatology Service, Maimonides Institute of Biomedical Research of Cordoba (IMIBIC),Reina Sofia University Hospital, University of Córdoba, Cordoba, Spain
| | - Cristobal Roman-Rodriguez
- Rheumatology Service, Maimonides Institute of Biomedical Research of Cordoba (IMIBIC),Reina Sofia University Hospital, University of Córdoba, Cordoba, Spain
| | - Mª Carmen Abalos-Aguilera
- Rheumatology Service, Maimonides Institute of Biomedical Research of Cordoba (IMIBIC),Reina Sofia University Hospital, University of Córdoba, Cordoba, Spain
| | - Carmen Conde
- Laboratorio de Investigación 8, Instituto de Investigación Sanitaria (IDIS), Hospital Clinico de Santiago (CHUS), Santiago de Compostela, Spain
| | - Antonio Gonzalez
- Experimental and Observational Rheumatology, Hospital Clinico Universitario de Santiago, Santiago de Compostela, Spain
| | - Sergio Pedraza-Arevalo
- Department of Cell Biology, Physiology and Immunology, Maimonides Institute of Biomedical Research of Cordoba (IMIBIC),Reina Sofia University Hospital, University of Córdoba and CIBER Fisiopatologia de la Obesidad y Nutricion (CIBERobn), Cordoba, Spain
| | - Mercedes Del Rio-Moreno
- Department of Cell Biology, Physiology and Immunology, Maimonides Institute of Biomedical Research of Cordoba (IMIBIC),Reina Sofia University Hospital, University of Córdoba and CIBER Fisiopatologia de la Obesidad y Nutricion (CIBERobn), Cordoba, Spain
| | - Ricardo Blazquez-Encinas
- Department of Cell Biology, Physiology and Immunology, Maimonides Institute of Biomedical Research of Cordoba (IMIBIC),Reina Sofia University Hospital, University of Córdoba and CIBER Fisiopatologia de la Obesidad y Nutricion (CIBERobn), Cordoba, Spain
| | - Pedro Segui
- Radiology Service, Maimonides Institute of Biomedical Research of Cordoba (IMIBIC),Reina Sofia University Hospital, University of Córdoba, Cordoba, Spain
| | - Jerusalem Calvo
- Rheumatology Service, Maimonides Institute of Biomedical Research of Cordoba (IMIBIC),Reina Sofia University Hospital, University of Córdoba, Cordoba, Spain
| | - Rafaela Ortega Castro
- Rheumatology Service, Maimonides Institute of Biomedical Research of Cordoba (IMIBIC),Reina Sofia University Hospital, University of Córdoba, Cordoba, Spain
| | - Alejandro Escudero-Contreras
- Rheumatology Service, Maimonides Institute of Biomedical Research of Cordoba (IMIBIC),Reina Sofia University Hospital, University of Córdoba, Cordoba, Spain
| | - Nuria Barbarroja
- Rheumatology Service, Maimonides Institute of Biomedical Research of Cordoba (IMIBIC),Reina Sofia University Hospital, University of Córdoba, Cordoba, Spain
| | - Mª Angeles Aguirre
- Rheumatology Service, Maimonides Institute of Biomedical Research of Cordoba (IMIBIC),Reina Sofia University Hospital, University of Córdoba, Cordoba, Spain
| | - Justo P Castaño
- Department of Cell Biology, Physiology and Immunology, Maimonides Institute of Biomedical Research of Cordoba (IMIBIC),Reina Sofia University Hospital, University of Córdoba and CIBER Fisiopatologia de la Obesidad y Nutricion (CIBERobn), Cordoba, Spain
| | - Raul M Luque
- Department of Cell Biology, Physiology and Immunology, Maimonides Institute of Biomedical Research of Cordoba (IMIBIC),Reina Sofia University Hospital, University of Córdoba and CIBER Fisiopatologia de la Obesidad y Nutricion (CIBERobn), Cordoba, Spain
| | - Eduardo Collantes-Estevez
- Rheumatology Service, Maimonides Institute of Biomedical Research of Cordoba (IMIBIC),Reina Sofia University Hospital, University of Córdoba, Cordoba, Spain
| | - Chary Lopez-Pedrera
- Rheumatology Service, Maimonides Institute of Biomedical Research of Cordoba (IMIBIC),Reina Sofia University Hospital, University of Córdoba, Cordoba, Spain
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13
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Akinyi MV, Frilander MJ. At the Intersection of Major and Minor Spliceosomes: Crosstalk Mechanisms and Their Impact on Gene Expression. Front Genet 2021; 12:700744. [PMID: 34354740 PMCID: PMC8329584 DOI: 10.3389/fgene.2021.700744] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Accepted: 06/28/2021] [Indexed: 11/17/2022] Open
Abstract
Many eukaryotic species contain two separate molecular machineries for removing non-coding intron sequences from pre-mRNA molecules. The majority of introns (more than 99.5% in humans) are recognized and excised by the major spliceosome, which utilizes relatively poorly conserved sequence elements at the 5′ and 3′ ends of the intron that are used for intron recognition and in subsequent catalysis. In contrast, the minor spliceosome targets a rare group of introns (approximately 0.5% in humans) with highly conserved sequences at the 5′ and 3′ ends of the intron. Minor introns coexist in the same genes with major introns and while the two intron types are spliced by separate spliceosomes, the two splicing machineries can interact with one another to shape mRNA processing events in genes containing minor introns. Here, we review known cooperative and competitive interactions between the two spliceosomes and discuss the mechanistic basis of the spliceosome crosstalk, its regulatory significance, and impact on spliceosome diseases.
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Affiliation(s)
- Maureen V Akinyi
- Institute of Biotechnology/Helsinki Institute of Life Science, University of Helsinki, Helsinki, Finland
| | - Mikko J Frilander
- Institute of Biotechnology/Helsinki Institute of Life Science, University of Helsinki, Helsinki, Finland
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14
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de Wolf B, Oghabian A, Akinyi MV, Hanks S, Tromer EC, van Hooff JJE, van Voorthuijsen L, van Rooijen LE, Verbeeren J, Uijttewaal ECH, Baltissen MPA, Yost S, Piloquet P, Vermeulen M, Snel B, Isidor B, Rahman N, Frilander MJ, Kops GJPL. Chromosomal instability by mutations in the novel minor spliceosome component CENATAC. EMBO J 2021; 40:e106536. [PMID: 34009673 PMCID: PMC8280824 DOI: 10.15252/embj.2020106536] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2020] [Revised: 04/16/2021] [Accepted: 04/19/2021] [Indexed: 12/22/2022] Open
Abstract
Aneuploidy is the leading cause of miscarriage and congenital birth defects, and a hallmark of cancer. Despite this strong association with human disease, the genetic causes of aneuploidy remain largely unknown. Through exome sequencing of patients with constitutional mosaic aneuploidy, we identified biallelic truncating mutations in CENATAC (CCDC84). We show that CENATAC is a novel component of the minor (U12-dependent) spliceosome that promotes splicing of a specific, rare minor intron subtype. This subtype is characterized by AT-AN splice sites and relatively high basal levels of intron retention. CENATAC depletion or expression of disease mutants resulted in excessive retention of AT-AN minor introns in ˜ 100 genes enriched for nucleocytoplasmic transport and cell cycle regulators, and caused chromosome segregation errors. Our findings reveal selectivity in minor intron splicing and suggest a link between minor spliceosome defects and constitutional aneuploidy in humans.
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Affiliation(s)
- Bas de Wolf
- Oncode InstituteHubrecht Institute ‐ Royal Academy of Arts and Sciences and University Medical Centre UtrechtUtrechtThe Netherlands
| | - Ali Oghabian
- Institute of BiotechnologyHelsinki Institute of Life ScienceUniversity of HelsinkiHelsinkiFinland
- Present address:
Faculty of MedicineResearch Programs UnitUniversity of HelsinkiHelsinkiFinland
| | - Maureen V Akinyi
- Institute of BiotechnologyHelsinki Institute of Life ScienceUniversity of HelsinkiHelsinkiFinland
| | - Sandra Hanks
- Division of Genetics and EpidemiologyInstitute of Cancer ResearchLondonUK
| | - Eelco C Tromer
- Oncode InstituteHubrecht Institute ‐ Royal Academy of Arts and Sciences and University Medical Centre UtrechtUtrechtThe Netherlands
- Theoretical Biology and Bioinformatics, BiologyScience FacultyUtrecht UniversityUtrechtThe Netherlands
- Present address:
Department of BiochemistryUniversity of CambridgeCambridgeUK
| | - Jolien J E van Hooff
- Oncode InstituteHubrecht Institute ‐ Royal Academy of Arts and Sciences and University Medical Centre UtrechtUtrechtThe Netherlands
- Theoretical Biology and Bioinformatics, BiologyScience FacultyUtrecht UniversityUtrechtThe Netherlands
- Present address:
Unité d'EcologieSystématique et EvolutionCNRSUniversité Paris‐SudUniversité Paris‐SaclayAgroParisTechOrsayFrance
| | - Lisa van Voorthuijsen
- Oncode InstituteDepartment of Molecular BiologyFaculty of ScienceRadboud Institute for Molecular Life ScienceRadboud University NijmegenNijmegenThe Netherlands
| | - Laura E van Rooijen
- Theoretical Biology and Bioinformatics, BiologyScience FacultyUtrecht UniversityUtrechtThe Netherlands
| | - Jens Verbeeren
- Institute of BiotechnologyHelsinki Institute of Life ScienceUniversity of HelsinkiHelsinkiFinland
| | - Esther C H Uijttewaal
- Oncode InstituteHubrecht Institute ‐ Royal Academy of Arts and Sciences and University Medical Centre UtrechtUtrechtThe Netherlands
| | - Marijke P A Baltissen
- Oncode InstituteDepartment of Molecular BiologyFaculty of ScienceRadboud Institute for Molecular Life ScienceRadboud University NijmegenNijmegenThe Netherlands
| | - Shawn Yost
- Division of Genetics and EpidemiologyInstitute of Cancer ResearchLondonUK
| | - Philippe Piloquet
- Service de Génétique MédicaleUnité de génétique CliniqueCHU Hotel DieuNantes CedexFrance
| | - Michiel Vermeulen
- Oncode InstituteDepartment of Molecular BiologyFaculty of ScienceRadboud Institute for Molecular Life ScienceRadboud University NijmegenNijmegenThe Netherlands
| | - Berend Snel
- Theoretical Biology and Bioinformatics, BiologyScience FacultyUtrecht UniversityUtrechtThe Netherlands
| | - Bertrand Isidor
- Service de Génétique MédicaleUnité de génétique CliniqueCHU Hotel DieuNantes CedexFrance
| | - Nazneen Rahman
- Division of Genetics and EpidemiologyInstitute of Cancer ResearchLondonUK
| | - Mikko J Frilander
- Institute of BiotechnologyHelsinki Institute of Life ScienceUniversity of HelsinkiHelsinkiFinland
| | - Geert J P L Kops
- Oncode InstituteHubrecht Institute ‐ Royal Academy of Arts and Sciences and University Medical Centre UtrechtUtrechtThe Netherlands
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15
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Minor Intron Splicing from Basic Science to Disease. Int J Mol Sci 2021; 22:ijms22116062. [PMID: 34199764 PMCID: PMC8199999 DOI: 10.3390/ijms22116062] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2021] [Revised: 05/17/2021] [Accepted: 05/18/2021] [Indexed: 01/14/2023] Open
Abstract
Pre-mRNA splicing is an essential step in gene expression and is catalyzed by two machineries in eukaryotes: the major (U2 type) and minor (U12 type) spliceosomes. While the majority of introns in humans are U2 type, less than 0.4% are U12 type, also known as minor introns (mi-INTs), and require a specialized spliceosome composed of U11, U12, U4atac, U5, and U6atac snRNPs. The high evolutionary conservation and apparent splicing inefficiency of U12 introns have set them apart from their major counterparts and led to speculations on the purpose for their existence. However, recent studies challenged the simple concept of mi-INTs splicing inefficiency due to low abundance of their spliceosome and confirmed their regulatory role in alternative splicing, significantly impacting the expression of their host genes. Additionally, a growing list of minor spliceosome-associated diseases with tissue-specific pathologies affirmed the importance of minor splicing as a key regulatory pathway, which when deregulated could lead to tissue-specific pathologies due to specific alterations in the expression of some minor-intron-containing genes. Consequently, uncovering how mi-INTs splicing is regulated in a tissue-specific manner would allow for better understanding of disease pathogenesis and pave the way for novel therapies, which we highlight in this review.
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16
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El Marabti E, Abdel-Wahab O. Therapeutic Modulation of RNA Splicing in Malignant and Non-Malignant Disease. Trends Mol Med 2021; 27:643-659. [PMID: 33994320 DOI: 10.1016/j.molmed.2021.04.005] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2021] [Revised: 04/11/2021] [Accepted: 04/13/2021] [Indexed: 01/24/2023]
Abstract
RNA splicing is the enzymatic process by which non-protein coding sequences are removed from RNA to produce mature protein-coding mRNA. Splicing is thereby a major mediator of proteome diversity as well as a dynamic regulator of gene expression. Genetic alterations disrupting splicing of individual genes or altering the function of splicing factors contribute to a wide range of human genetic diseases as well as cancer. These observations have resulted in the development of therapies based on oligonucleotides that bind to RNA sequences and modulate splicing for therapeutic benefit. In parallel, small molecules that bind to splicing factors to alter their function or modify RNA processing of individual transcripts are being pursued for monogenic disorders as well as for cancer.
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Affiliation(s)
- Ettaib El Marabti
- Clinical Transplant Research Division, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
| | - Omar Abdel-Wahab
- Human Oncology and Pathogenesis Program, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA; Leukemia Service, Department of Medicine, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA.
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17
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Olthof AM, White AK, Mieruszynski S, Doggett K, Lee MF, Chakroun A, Abdel Aleem AK, Rousseau J, Magnani C, Roifman CM, Campeau PM, Heath JK, Kanadia RN. Disruption of exon-bridging interactions between the minor and major spliceosomes results in alternative splicing around minor introns. Nucleic Acids Res 2021; 49:3524-3545. [PMID: 33660780 PMCID: PMC8034651 DOI: 10.1093/nar/gkab118] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Revised: 02/08/2021] [Accepted: 02/10/2021] [Indexed: 12/11/2022] Open
Abstract
Vertebrate genomes contain major (>99.5%) and minor (<0.5%) introns that are spliced by the major and minor spliceosomes, respectively. Major intron splicing follows the exon-definition model, whereby major spliceosome components first assemble across exons. However, since most genes with minor introns predominately consist of major introns, formation of exon-definition complexes in these genes would require interaction between the major and minor spliceosomes. Here, we report that minor spliceosome protein U11-59K binds to the major spliceosome U2AF complex, thereby supporting a model in which the minor spliceosome interacts with the major spliceosome across an exon to regulate the splicing of minor introns. Inhibition of minor spliceosome snRNAs and U11-59K disrupted exon-bridging interactions, leading to exon skipping by the major spliceosome. The resulting aberrant isoforms contained a premature stop codon, yet were not subjected to nonsense-mediated decay, but rather bound to polysomes. Importantly, we detected elevated levels of these alternatively spliced transcripts in individuals with minor spliceosome-related diseases such as Roifman syndrome, Lowry–Wood syndrome and early-onset cerebellar ataxia. In all, we report that the minor spliceosome informs splicing by the major spliceosome through exon-definition interactions and show that minor spliceosome inhibition results in aberrant alternative splicing in disease.
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Affiliation(s)
- Anouk M Olthof
- Physiology and Neurobiology Department, University of Connecticut, 75 N. Eagleville Road, Storrs, CT 06269, USA
| | - Alisa K White
- Physiology and Neurobiology Department, University of Connecticut, 75 N. Eagleville Road, Storrs, CT 06269, USA
| | - Stephen Mieruszynski
- Epigenetics and Development Division, Walter and Eliza Hall Institute of Medical Research, Parkville, VIC 3052, Australia
| | - Karen Doggett
- Epigenetics and Development Division, Walter and Eliza Hall Institute of Medical Research, Parkville, VIC 3052, Australia
| | - Madisen F Lee
- Physiology and Neurobiology Department, University of Connecticut, 75 N. Eagleville Road, Storrs, CT 06269, USA
| | | | | | - Justine Rousseau
- CHU Sainte-Justine Research Center, Montreal, QC H3T 1C5, Canada
| | - Cinzia Magnani
- Neonatology and Neonatal Intensive Care Unit, Maternal and Child Department, University of Parma, Parma, 43121, Italy
| | - Chaim M Roifman
- Division of Immunology and Allergy, Department of Pediatrics, The Hospital for Sick Children and the University of Toronto, Toronto, ON M5G 1X8, Canada.,The Canadian Centre for Primary Immunodeficiency and The Jeffrey Modell Research Laboratory for the Diagnosis of Primary Immunodeficiency, The Hospital for Sick Children, Toronto, ON M5G 1X8, Canada
| | - Philippe M Campeau
- Department of Pediatrics, University of Montreal, Montreal, QC H4A 3J1, Canada
| | - Joan K Heath
- Epigenetics and Development Division, Walter and Eliza Hall Institute of Medical Research, Parkville, VIC 3052, Australia
| | - Rahul N Kanadia
- Physiology and Neurobiology Department, University of Connecticut, 75 N. Eagleville Road, Storrs, CT 06269, USA.,Institute for System Genomics, University of Connecticut, Storrs, CT 06269, USA
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18
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Norppa AJ, Frilander MJ. The integrity of the U12 snRNA 3' stem-loop is necessary for its overall stability. Nucleic Acids Res 2021; 49:2835-2847. [PMID: 33577674 PMCID: PMC7968993 DOI: 10.1093/nar/gkab048] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Revised: 01/14/2021] [Accepted: 02/07/2021] [Indexed: 12/20/2022] Open
Abstract
Disruption of minor spliceosome functions underlies several genetic diseases with mutations in the minor spliceosome-specific small nuclear RNAs (snRNAs) and proteins. Here, we define the molecular outcome of the U12 snRNA mutation (84C>U) resulting in an early-onset form of cerebellar ataxia. To understand the molecular consequences of the U12 snRNA mutation, we created cell lines harboring the 84C>T mutation in the U12 snRNA gene (RNU12). We show that the 84C>U mutation leads to accelerated decay of the snRNA, resulting in significantly reduced steady-state U12 snRNA levels. Additionally, the mutation leads to accumulation of 3′-truncated forms of U12 snRNA, which have undergone the cytoplasmic steps of snRNP biogenesis. Our data suggests that the 84C>U-mutant snRNA is targeted for decay following reimport into the nucleus, and that the U12 snRNA fragments are decay intermediates that result from the stalling of a 3′-to-5′ exonuclease. Finally, we show that several other single-nucleotide variants in the 3′ stem-loop of U12 snRNA that are segregating in the human population are also highly destabilizing. This suggests that the 3′ stem-loop is important for the overall stability of the U12 snRNA and that additional disease-causing mutations are likely to exist in this region.
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Affiliation(s)
- Antto J Norppa
- Institute of Biotechnology, P.O. Box 56, Viikinkaari 5, University of Helsinki, FI-00014 Helsinki, Finland
| | - Mikko J Frilander
- Institute of Biotechnology, P.O. Box 56, Viikinkaari 5, University of Helsinki, FI-00014 Helsinki, Finland
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19
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Madan V, Cao Z, Teoh WW, Dakle P, Han L, Shyamsunder P, Jeitany M, Zhou S, Li J, Nordin HBM, Shi J, Yu S, Yang H, Hossain MZ, Chng WJ, Koeffler HP. ZRSR1 cooperates with ZRSR2 in regulating splicing of U12-type introns in murine hematopoietic cells. Haematologica 2021; 107:680-689. [PMID: 33691379 PMCID: PMC8883539 DOI: 10.3324/haematol.2020.260562] [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: 05/24/2020] [Indexed: 12/03/2022] Open
Abstract
Recurrent loss-of-function mutations of spliceosome gene, ZRSR2, occur in myelodysplastic syndromes (MDS). Mutation/loss of ZRSR2 in human myeloid cells primarily causes impaired splicing of the U12-type introns. In order to further investigate the role of this splice factor in RNA splicing and hematopoietic development, we generated mice lacking ZRSR2. Unexpectedly, Zrsr2-deficient mice developed normal hematopoiesis with no abnormalities in myeloid differentiation evident in either young or ≥1-year old knockout mice. Repopulation ability of Zrsr2-deficient hematopoietic stem cells was also unaffected in both competitive and non-competitive reconstitution assays. Myeloid progenitors lacking ZRSR2 exhibited mis-splicing of U12-type introns, however, this phenotype was moderate compared to the ZRSR2-deficient human cells. Our investigations revealed that a closely related homolog, Zrsr1, expressed in the murine hematopoietic cells, but not in human cells contributes to splicing of U12-type introns. Depletion of Zrsr1 in Zrsr2 KO myeloid cells exacerbated retention of the U12-type introns, thus highlighting a collective role of ZRSR1 and ZRSR2 in murine U12-spliceosome. We also demonstrate that aberrant retention of U12-type introns of MAPK9 and MAPK14 leads to their reduced protein expression. Overall, our findings highlight that both ZRSR1 and ZRSR2 are functional components of the murine U12-spliceosome, and depletion of both proteins is required to accurately model ZRSR2-mutant MDS in mice.
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Affiliation(s)
- Vikas Madan
- Cancer Science Institute of Singapore, National University of Singapore, Singapore.
| | - Zeya Cao
- Cancer Science Institute of Singapore, National University of Singapore, Singapore; Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Weoi Woon Teoh
- Cancer Science Institute of Singapore, National University of Singapore, Singapore
| | - Pushkar Dakle
- Cancer Science Institute of Singapore, National University of Singapore, Singapore
| | - Lin Han
- Cancer Science Institute of Singapore, National University of Singapore, Singapore; Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Pavithra Shyamsunder
- Cancer Science Institute of Singapore, National University of Singapore, Singapore; Programme in Cancer and Stem Cell Biology, Duke-NUS Medical School, Singapore
| | - Maya Jeitany
- Cancer Science Institute of Singapore, National University of Singapore, Singapore; School of Biological Sciences, Nanyang Technological University, Singapore
| | - Siqin Zhou
- Cancer Science Institute of Singapore, National University of Singapore, Singapore
| | - Jia Li
- Cancer Science Institute of Singapore, National University of Singapore, Singapore
| | | | - JiZhong Shi
- Cancer Science Institute of Singapore, National University of Singapore, Singapore
| | - Shuizhou Yu
- Cancer Science Institute of Singapore, National University of Singapore, Singapore
| | - Henry Yang
- Cancer Science Institute of Singapore, National University of Singapore, Singapore
| | - Md Zakir Hossain
- Cancer Science Institute of Singapore, National University of Singapore, Singapore
| | - Wee Joo Chng
- Cancer Science Institute of Singapore, National University of Singapore, Singapore; Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore; Hematology-Oncology, National University Cancer Institute, NUHS, Singapore
| | - H Phillip Koeffler
- Cancer Science Institute of Singapore, National University of Singapore, Singapore; Cedars-Sinai Medical Center, Division of Hematology/Oncology, UCLA School of Medicine, Los Angeles, USA; National University Cancer Institute, National University Hospital Singapore, Singapore
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20
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Moyer DC, Larue GE, Hershberger CE, Roy SW, Padgett RA. Comprehensive database and evolutionary dynamics of U12-type introns. Nucleic Acids Res 2020; 48:7066-7078. [PMID: 32484558 PMCID: PMC7367187 DOI: 10.1093/nar/gkaa464] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Revised: 05/19/2020] [Accepted: 05/20/2020] [Indexed: 12/16/2022] Open
Abstract
During nuclear maturation of most eukaryotic pre-messenger RNAs and long non-coding RNAs, introns are removed through the process of RNA splicing. Different classes of introns are excised by the U2-type or the U12-type spliceosomes, large complexes of small nuclear ribonucleoprotein particles and associated proteins. We created intronIC, a program for assigning intron class to all introns in a given genome, and used it on 24 eukaryotic genomes to create the Intron Annotation and Orthology Database (IAOD). We then used the data in the IAOD to revisit several hypotheses concerning the evolution of the two classes of spliceosomal introns, finding support for the class conversion model explaining the low abundance of U12-type introns in modern genomes.
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Affiliation(s)
- Devlin C Moyer
- Department of Cardiovascular and Metabolic Sciences, Lerner Research Institute, Cleveland Clinic Lerner College of Medicine, Cleveland Clinic and Department of Molecular Medicine, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Graham E Larue
- Department of Molecular and Cell Biology, University of California, Merced, Merced, CA 95343, USA
| | - Courtney E Hershberger
- Department of Cardiovascular and Metabolic Sciences, Lerner Research Institute, Cleveland Clinic Lerner College of Medicine, Cleveland Clinic and Department of Molecular Medicine, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Scott W Roy
- Department of Biology, San Francisco State University, San Francisco, CA 94132, USA
| | - Richard A Padgett
- Department of Cardiovascular and Metabolic Sciences, Lerner Research Institute, Cleveland Clinic Lerner College of Medicine, Cleveland Clinic and Department of Molecular Medicine, Case Western Reserve University, Cleveland, OH 44106, USA
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21
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Clinical interpretation of variants identified in RNU4ATAC, a non-coding spliceosomal gene. PLoS One 2020; 15:e0235655. [PMID: 32628740 PMCID: PMC7337319 DOI: 10.1371/journal.pone.0235655] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2020] [Accepted: 06/19/2020] [Indexed: 12/16/2022] Open
Abstract
Biallelic variants in RNU4ATAC, a non-coding gene transcribed into the minor spliceosome component U4atac snRNA, are responsible for three rare recessive developmental diseases, namely Taybi-Linder/MOPD1, Roifman and Lowry-Wood syndromes. Next-generation sequencing of clinically heterogeneous cohorts (children with either a suspected genetic disorder or a congenital microcephaly) recently identified mutations in this gene, illustrating how profoundly these technologies are modifying genetic testing and assessment. As RNU4ATAC has a single non-coding exon, the bioinformatic prediction algorithms assessing the effect of sequence variants on splicing or protein function are irrelevant, which makes variant interpretation challenging to molecular diagnostic laboratories. In order to facilitate and improve clinical diagnostic assessment and genetic counseling, we present i) an update of the previously reported RNU4ATAC mutations and an analysis of the genetic variations affecting this gene using the Genome Aggregation Database (gnomAD) resource; ii) the pathogenicity prediction performances of scores computed based on an RNA structure prediction tool and of those produced by the Combined Annotation Dependent Depletion tool for the 285 RNU4ATAC variants identified in patients or in large-scale sequencing projects; iii) a method, based on a cellular assay, that allows to measure the effect of RNU4ATAC variants on splicing efficiency of a minor (U12-type) reporter intron. Lastly, the concordance of bioinformatic predictions and cellular assay results was investigated.
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22
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Olthof AM, Rasmussen JS, Campeau PM, Kanadia RN. Disrupted minor intron splicing is prevalent in Mendelian disorders. Mol Genet Genomic Med 2020; 8:e1374. [PMID: 32573973 PMCID: PMC7507305 DOI: 10.1002/mgg3.1374] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2020] [Revised: 05/27/2020] [Accepted: 05/29/2020] [Indexed: 12/13/2022] Open
Abstract
Background Splicing is crucial for proper gene expression, and is predominately executed by the major spliceosome. Conversely, 722 introns in 699 human minor intron‐containing genes (MIGs) are spliced by the minor spliceosome. Splicing of these minor introns is disrupted in diseases caused by pathogenic variants in the minor spliceosome, ultimately leading to the aberrant expression of a subset of these MIGs. However, the effect of variants in minor introns and MIGs on diseases remains unexplored. Methods Variants in MIGs and associated clinical manifestations were identified using ClinVar. The HPO database was then used to curate the related symptoms and affected organ systems. Results: We found pathogenic variants in 211 MIGs, which commonly resulted in intellectual disability, seizures and microcephaly. This revealed a subset of MIGs whose aberrant splicing may contribute to the pathogenesis of minor spliceosome‐related diseases. Moreover, we identified 51 pathogenic variants in minor intron splice sites that reduce the splice site strength and can induce alternative splicing. Conclusion These findings highlight that disrupted minor intron splicing has a broader impact on human diseases than previously appreciated. The hope is that this knowledge will aid in the development of therapeutic strategies that incorporate the minor intron splicing pathway.
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Affiliation(s)
- Anouk M Olthof
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, CT, USA
| | - Jeffrey S Rasmussen
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, CT, USA
| | | | - Rahul N Kanadia
- Department of Physiology and Neurobiology, University of Connecticut, Storrs, CT, USA.,Institute for Systems Genomics, University of Connecticut, Storrs, CT, USA
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23
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Stracker TH, Morrison CG, Gergely F. Molecular causes of primary microcephaly and related diseases: a report from the UNIA Workshop. Chromosoma 2020; 129:115-120. [PMID: 32424716 DOI: 10.1007/s00412-020-00737-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2020] [Revised: 05/09/2020] [Accepted: 05/12/2020] [Indexed: 12/30/2022]
Abstract
The International University of Andalucía (UNIA) Current Trends in Biomedicine Workshop on Molecular Causes of Primary Microcephaly and Related Diseases took place in Baeza, Spain, November 18-20, 2019. This meeting brought together scientists from Europe, the USA and China to discuss recent advances in our molecular and genetic understanding of a group of rare neurodevelopmental diseases characterised by primary microcephaly, a condition in which head circumference is smaller than normal at birth. Microcephaly can be caused by inherited mutations that affect key cellular processes, or environmental exposure to radiation or other toxins. It can also result from viral infection, as exemplified by the recent Zika virus outbreak in South America. Here we summarise a number of the scientific advances presented and topics discussed at the meeting.
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Affiliation(s)
- Travis H Stracker
- Institute for Research in Biomedicine (IRB Barcelona) and Barcelona Institute of Science and Technology, 08028, Barcelona, Spain.
| | - Ciaran G Morrison
- Centre for Chromosome Biology, School of Natural Sciences, National University of Ireland Galway, Biosciences Building, Dangan, Galway, H91 TK33, Ireland
| | - Fanni Gergely
- Cancer Research UK Cambridge Institute, University of Cambridge, Li Ka Shing Centre, Robinson Way, Cambridge, CB2 0RE, UK
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24
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Beauchamp MC, Alam SS, Kumar S, Jerome-Majewska LA. Spliceosomopathies and neurocristopathies: Two sides of the same coin? Dev Dyn 2020; 249:924-945. [PMID: 32315467 DOI: 10.1002/dvdy.183] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Revised: 03/26/2020] [Accepted: 04/15/2020] [Indexed: 12/14/2022] Open
Abstract
Mutations in core components of the spliceosome are responsible for a group of syndromes collectively known as spliceosomopathies. Patients exhibit microcephaly, micrognathia, malar hypoplasia, external ear anomalies, eye anomalies, psychomotor delay, intellectual disability, limb, and heart defects. Craniofacial malformations in these patients are predominantly found in neural crest cells-derived structures of the face and head. Mutations in eight genes SNRPB, RNU4ATAC, SF3B4, PUF60, EFTUD2, TXNL4, EIF4A3, and CWC27 are associated with craniofacial spliceosomopathies. In this review, we provide a brief description of the normal development of the head and the face and an overview of mutations identified in genes associated with craniofacial spliceosomopathies. We also describe a model to explain how and when these mutations are most likely to impact neural crest cells. We speculate that mutations in a subset of core splicing factors lead to disrupted splicing in neural crest cells because these cells have increased sensitivity to inefficient splicing. Hence, disruption in splicing likely activates a cellular stress response that includes increased skipping of regulatory exons in genes such as MDM2 and MDM4, key regulators of P53. This would result in P53-associated death of neural crest cells and consequently craniofacial malformations associated with spliceosomopathies.
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Affiliation(s)
- Marie-Claude Beauchamp
- Department of Pediatrics, McGill University, Montreal, Quebec, Canada.,McGill University Health Centre at Glen Site, Montreal, Quebec, Canada
| | - Sabrina Shameen Alam
- McGill University Health Centre at Glen Site, Montreal, Quebec, Canada.,Department of Human Genetics, McGill University, Montreal, Quebec, Canada
| | - Shruti Kumar
- McGill University Health Centre at Glen Site, Montreal, Quebec, Canada.,Department of Human Genetics, McGill University, Montreal, Quebec, Canada
| | - Loydie Anne Jerome-Majewska
- Department of Pediatrics, McGill University, Montreal, Quebec, Canada.,McGill University Health Centre at Glen Site, Montreal, Quebec, Canada.,Department of Human Genetics, McGill University, Montreal, Quebec, Canada.,Department of Anatomy and Cell Biology, McGill University, Montreal, Quebec, Canada
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25
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Meinke S, Goldammer G, Weber AI, Tarabykin V, Neumann A, Preussner M, Heyd F. Srsf10 and the minor spliceosome control tissue-specific and dynamic SR protein expression. eLife 2020; 9:56075. [PMID: 32338600 PMCID: PMC7244321 DOI: 10.7554/elife.56075] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2020] [Accepted: 04/24/2020] [Indexed: 12/11/2022] Open
Abstract
Minor and major spliceosomes control splicing of distinct intron types and are thought to act largely independent of one another. SR proteins are essential splicing regulators mostly connected to the major spliceosome. Here, we show that Srsf10 expression is controlled through an autoregulated minor intron, tightly correlating Srsf10 with minor spliceosome abundance across different tissues and differentiation stages in mammals. Surprisingly, all other SR proteins also correlate with the minor spliceosome and Srsf10, and abolishing Srsf10 autoregulation by Crispr/Cas9-mediated deletion of the autoregulatory exon induces expression of all SR proteins in a human cell line. Our data thus reveal extensive crosstalk and a global impact of the minor spliceosome on major intron splicing.
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Affiliation(s)
- Stefan Meinke
- Freie Universität Berlin, Institute of Chemistry and Biochemistry, Laboratory of RNA Biochemistry, Berlin, Germany
| | - Gesine Goldammer
- Freie Universität Berlin, Institute of Chemistry and Biochemistry, Laboratory of RNA Biochemistry, Berlin, Germany
| | - A Ioana Weber
- Freie Universität Berlin, Institute of Chemistry and Biochemistry, Laboratory of RNA Biochemistry, Berlin, Germany.,Institute of Cell Biology and Neurobiology, Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Victor Tarabykin
- Institute of Cell Biology and Neurobiology, Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany
| | - Alexander Neumann
- Freie Universität Berlin, Institute of Chemistry and Biochemistry, Laboratory of RNA Biochemistry, Berlin, Germany
| | - Marco Preussner
- Freie Universität Berlin, Institute of Chemistry and Biochemistry, Laboratory of RNA Biochemistry, Berlin, Germany
| | - Florian Heyd
- Freie Universität Berlin, Institute of Chemistry and Biochemistry, Laboratory of RNA Biochemistry, Berlin, Germany
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