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Habib C, Paperna T, Zaid R, Ravid S, Ben Ari J, Tal G, Weiss K, Hershkovitz T. Rapid exome sequencing for children with severe acute encephalopathy - A case series. Eur J Med Genet 2024; 68:104918. [PMID: 38325642 DOI: 10.1016/j.ejmg.2024.104918] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2023] [Revised: 09/11/2023] [Accepted: 02/03/2024] [Indexed: 02/09/2024]
Abstract
Increasingly, next-generation sequencing (NGS) is becoming an invaluable tool in the diagnosis of unexplained acute neurological disorders, such as acute encephalopathy/encephalitis. Here, we describe a brief series of pediatric patients who presented at the pediatric intensive care unit with severe acute encephalopathy, initially suspected as infectious or inflammatory but subsequently diagnosed with a monogenic disorder. Rapid exome sequencing was performed during the initial hospitalization of three unrelated patients, and results were delivered within 7-21 days. All patients were previously healthy, 1.5-3 years old, of Muslim Arab descent, with consanguineous parents. One patient presenting with acute necrotizing encephalopathy (ANEC). Her sister presented with ANEC one year prior. Exome sequencing was diagnostic in all three patients. All were homozygous for pathogenic and likely-pathogenic variants associated with recessive disorders; MOCS2, NDUFS8 and DBR1. Surprisingly, the initial workup was not suggestive of the final diagnosis. This case series demonstrates that the use of rapid exome sequencing is shifting the paradigm of diagnostics even in critical care situations and should be considered early on in children with acute encephalopathy. A timely diagnosis can direct initial treatment as well as inform decisions regarding long-term care.
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Affiliation(s)
- Clair Habib
- The Genetics Institute, Rambam Health Care Campus, Haifa, Israel.
| | - Tamar Paperna
- The Genetics Institute, Rambam Health Care Campus, Haifa, Israel
| | - Rinat Zaid
- The Genetics Institute, Rambam Health Care Campus, Haifa, Israel
| | - Sarit Ravid
- Pediatric Neurology Department, Rambam Health Care Campus, Haifa, Israel
| | - Josef Ben Ari
- Pediatric Intensive Care Unit, Rambam Health Care Campus, Haifa, Israel
| | - Galit Tal
- The Ruth & Bruce Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, Haifa, Israel; Metabolic Clinic, Rambam Health Care Campus, Haifa, Israel
| | - Karin Weiss
- The Genetics Institute, Rambam Health Care Campus, Haifa, Israel; The Ruth & Bruce Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, Haifa, Israel
| | - Tova Hershkovitz
- The Genetics Institute, Rambam Health Care Campus, Haifa, Israel; The Ruth & Bruce Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, Haifa, Israel.
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2
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Theil AF, Pines A, Kalayci T, Heredia‐Genestar JM, Raams A, Rietveld MH, Sridharan S, Tanis SEJ, Mulder KW, Büyükbabani N, Karaman B, Uyguner ZO, Kayserili H, Hoeijmakers JHJ, Lans H, Demmers JAA, Pothof J, Altunoglu U, El Ghalbzouri A, Vermeulen W. Trichothiodystrophy-associated MPLKIP maintains DBR1 levels for proper lariat debranching and ectodermal differentiation. EMBO Mol Med 2023; 15:e17973. [PMID: 37800682 PMCID: PMC10630875 DOI: 10.15252/emmm.202317973] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2023] [Revised: 09/15/2023] [Accepted: 09/18/2023] [Indexed: 10/07/2023] Open
Abstract
The brittle hair syndrome Trichothiodystrophy (TTD) is characterized by variable clinical features, including photosensitivity, ichthyosis, growth retardation, microcephaly, intellectual disability, hypogonadism, and anaemia. TTD-associated mutations typically cause unstable mutant proteins involved in various steps of gene expression, severely reducing steady-state mutant protein levels. However, to date, no such link to instability of gene-expression factors for TTD-associated mutations in MPLKIP/TTDN1 has been established. Here, we present seven additional TTD individuals with MPLKIP mutations from five consanguineous families, with a newly identified MPLKIP variant in one family. By mass spectrometry-based interaction proteomics, we demonstrate that MPLKIP interacts with core splicing factors and the lariat debranching protein DBR1. MPLKIP-deficient primary fibroblasts have reduced steady-state DBR1 protein levels. Using Human Skin Equivalents (HSEs), we observed impaired keratinocyte differentiation associated with compromised splicing and eventually, an imbalanced proteome affecting skin development and, interestingly, also the immune system. Our data show that MPLKIP, through its DBR1 stabilizing role, is implicated in mRNA splicing, which is of particular importance in highly differentiated tissue.
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Affiliation(s)
- Arjan F Theil
- Department of Molecular GeneticsErasmus MC Cancer InstituteRotterdamThe Netherlands
| | - Alex Pines
- Department of Molecular GeneticsErasmus MC Cancer InstituteRotterdamThe Netherlands
| | - Tuğba Kalayci
- Department of Medical Genetics, Istanbul Faculty of MedicineIstanbul UniversityIstanbulTurkey
| | | | - Anja Raams
- Department of Molecular GeneticsErasmus MC Cancer InstituteRotterdamThe Netherlands
| | - Marion H Rietveld
- Department of DermatologyLeiden University Medical Center (LUMC)LeidenThe Netherlands
| | - Sriram Sridharan
- Cancer Science Institute of SingaporeNational University of SingaporeSingaporeSingapore
| | - Sabine EJ Tanis
- Department of Molecular Developmental Biology, Faculty of Science, Radboud Institute for Molecular Life SciencesRadboud UniversityNijmegenThe Netherlands
| | - Klaas W Mulder
- Department of Molecular Developmental Biology, Faculty of Science, Radboud Institute for Molecular Life SciencesRadboud UniversityNijmegenThe Netherlands
| | - Nesimi Büyükbabani
- Department of Pathology, Istanbul Faculty of MedicineIstanbul UniversityIstanbulTurkey
- Department of Medical GeneticsKoc University HospitalIstanbulTurkey
| | - Birsen Karaman
- Department of Medical Genetics, Istanbul Faculty of MedicineIstanbul UniversityIstanbulTurkey
- Department of Pediatric Basic Sciences, Child Health InstituteIstanbul UniversityIstanbulTurkey
| | - Zehra O Uyguner
- Department of Medical Genetics, Istanbul Faculty of MedicineIstanbul UniversityIstanbulTurkey
| | - Hülya Kayserili
- Department of Medical Genetics, Istanbul Faculty of MedicineIstanbul UniversityIstanbulTurkey
- Department of Medical GeneticsKoc University School of Medicine (KUSOM)IstanbulTurkey
| | - Jan HJ Hoeijmakers
- Department of Molecular GeneticsErasmus MC Cancer InstituteRotterdamThe Netherlands
- Institute for Genome Stability in Aging and Disease, CECAD ForschungszentrumUniversity Hospital of CologneKölnGermany
- Princess Máxima Center for Pediatric OncologyONCODE InstituteUtrechtThe Netherlands
| | - Hannes Lans
- Department of Molecular GeneticsErasmus MC Cancer InstituteRotterdamThe Netherlands
| | | | - Joris Pothof
- Department of Molecular GeneticsErasmus MC Cancer InstituteRotterdamThe Netherlands
| | - Umut Altunoglu
- Department of Medical Genetics, Istanbul Faculty of MedicineIstanbul UniversityIstanbulTurkey
- Department of Medical GeneticsKoc University School of Medicine (KUSOM)IstanbulTurkey
| | | | - Wim Vermeulen
- Department of Molecular GeneticsErasmus MC Cancer InstituteRotterdamThe Netherlands
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3
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Clark NE, Katolik A, Gallant P, Welch A, Murphy E, Buerer L, Schorl C, Naik N, Naik MT, Holloway SP, Cano K, Weintraub ST, Howard KM, Hart PJ, Jogl G, Damha MJ, Fairbrother WG. Activation of human RNA lariat debranching enzyme Dbr1 by binding protein TTDN1 occurs though an intrinsically disordered C-terminal domain. J Biol Chem 2023; 299:105100. [PMID: 37507019 PMCID: PMC10470207 DOI: 10.1016/j.jbc.2023.105100] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2023] [Revised: 07/11/2023] [Accepted: 07/20/2023] [Indexed: 07/30/2023] Open
Abstract
In eukaryotic cells, the introns are excised from pre-mRNA by the spliceosome. These introns typically have a lariat configuration due to the 2'-5' phosphodiester bond between an internal branched residue and the 5' terminus of the RNA. The only enzyme known to selectively hydrolyze the 2'-5' linkage of these lariats is the RNA lariat debranching enzyme Dbr1. In humans, Dbr1 is involved in processes such as class-switch recombination of immunoglobulin genes, and its dysfunction is implicated in viral encephalitis, HIV, ALS, and cancer. However, mechanistic details of precisely how Dbr1 affects these processes are missing. Here we show that human Dbr1 contains a disordered C-terminal domain through sequence analysis and nuclear magnetic resonance. This domain stabilizes Dbr1 in vitro by reducing aggregation but is dispensable for debranching activity. We establish that Dbr1 requires Fe2+ for efficient catalysis and demonstrate that the noncatalytic protein Drn1 and the uncharacterized protein trichothiodystrophy nonphotosensitive 1 directly bind to Dbr1. We demonstrate addition of trichothiodystrophy nonphotosensitive 1 to in vitro debranching reactions increases the catalytic efficiency of human Dbr1 19-fold but has no effect on the activity of Dbr1 from the amoeba Entamoeba histolytica, which lacks a disordered C-terminal domain. Finally, we systematically examine how the identity of the branchpoint nucleotide affects debranching rates. These findings describe new aspects of Dbr1 function in humans and further clarify how Dbr1 contributes to human health and disease.
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Affiliation(s)
- Nathaniel E Clark
- Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence, Rhode Island, USA.
| | - Adam Katolik
- Department of Chemistry, McGill University, Montreal, Quebec, Canada
| | - Pascal Gallant
- Department of Chemistry, McGill University, Montreal, Quebec, Canada
| | - Anastasia Welch
- Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence, Rhode Island, USA
| | - Eileen Murphy
- Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence, Rhode Island, USA
| | - Luke Buerer
- Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence, Rhode Island, USA
| | - Christoph Schorl
- Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence, Rhode Island, USA
| | - Nandita Naik
- Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence, Rhode Island, USA
| | - Mandar T Naik
- Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence, Rhode Island, USA
| | - Stephen P Holloway
- Department of Biochemistry and Structural Biology, University of Texas Health Science Center, San Antonio, Texas, USA
| | - Kristin Cano
- Department of Biochemistry and Structural Biology, University of Texas Health Science Center, San Antonio, Texas, USA
| | - Susan T Weintraub
- Department of Biochemistry and Structural Biology, University of Texas Health Science Center, San Antonio, Texas, USA
| | - Katherine M Howard
- Department of Biomedical Sciences, School of Dental Medicine, University of Nevada-Las Vegas, Las Vegas, Nevada, USA
| | - P John Hart
- Department of Biochemistry and Structural Biology, University of Texas Health Science Center, San Antonio, Texas, USA
| | - Gerwald Jogl
- Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence, Rhode Island, USA
| | - Masad J Damha
- Department of Chemistry, McGill University, Montreal, Quebec, Canada.
| | - William G Fairbrother
- Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence, Rhode Island, USA.
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4
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Rasmussen A, Okholm T, Knudsen M, Vang S, Dyrskjøt L, Hansen T, Pedersen J. Circular stable intronic RNAs possess distinct biological features and are deregulated in bladder cancer. NAR Cancer 2023; 5:zcad041. [PMID: 37554968 PMCID: PMC10405568 DOI: 10.1093/narcan/zcad041] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2022] [Accepted: 08/02/2023] [Indexed: 08/10/2023] Open
Abstract
Until recently, intronic lariats were regarded as short-lasting splicing byproducts with no apparent function; however, increasing evidence of stable derivatives suggests regulatory roles. Yet little is known about their characteristics, functions, distribution, and expression in healthy and tumor tissue. Here, we profiled and characterized circular stable intronic sequence RNAs (sisRNAs) using total RNA-Seq data from bladder cancer (BC; n = 457, UROMOL cohort), healthy tissue (n = 46), and fractionated cell lines (n = 5). We found that the recently-discovered full-length intronic circles and the stable lariats formed distinct subclasses, with a surprisingly high intronic circle fraction in BC (∼45%) compared to healthy tissues (0-20%). The stable lariats and their host introns were characterized by small transcript sizes, highly conserved BP regions, enriched BP motifs, and localization in multiple cell fractions. Additionally, circular sisRNAs showed tissue-specific expression patterns. We found nine circular sisRNAs as differentially expressed across early-stage BC patients with different prognoses, and sisHNRNPK expression correlated with progression-free survival. In conclusion, we identify distinguishing biological features of circular sisRNAs and point to specific candidates (incl. sisHNRNPK, sisWDR13 and sisMBNL1) that were highly expressed, had evolutionary conserved sequences, or had clinical correlations, which may facilitate future studies and further insights into their functional roles.
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Affiliation(s)
- Asta M Rasmussen
- Department of Clinical Medicine, Aarhus University, Aarhus 8000, Denmark
- Department of Molecular Medicine (MOMA), Aarhus University Hospital, Aarhus N 8200, Denmark
- Bioinformatics Research Center (BiRC), Aarhus University, Aarhus 8000, Denmark
| | - Trine Line H Okholm
- Departments of Otolaryngology-Head and Neck Surgery and Microbiology & Immunology, University of California, San Francisco, CA, USA
| | - Michael Knudsen
- Department of Clinical Medicine, Aarhus University, Aarhus 8000, Denmark
- Department of Molecular Medicine (MOMA), Aarhus University Hospital, Aarhus N 8200, Denmark
| | - Søren Vang
- Department of Clinical Medicine, Aarhus University, Aarhus 8000, Denmark
- Department of Molecular Medicine (MOMA), Aarhus University Hospital, Aarhus N 8200, Denmark
| | - Lars Dyrskjøt
- Department of Clinical Medicine, Aarhus University, Aarhus 8000, Denmark
- Department of Molecular Medicine (MOMA), Aarhus University Hospital, Aarhus N 8200, Denmark
| | - Thomas B Hansen
- Department of Molecular Biology and Genetics (MBG), Aarhus University, Aarhus 8000, Denmark
| | - Jakob S Pedersen
- Department of Clinical Medicine, Aarhus University, Aarhus 8000, Denmark
- Department of Molecular Medicine (MOMA), Aarhus University Hospital, Aarhus N 8200, Denmark
- Bioinformatics Research Center (BiRC), Aarhus University, Aarhus 8000, Denmark
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5
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Hoppe ER, Udy DB, Bradley RK. Recursive splicing discovery using lariats in total RNA sequencing. Life Sci Alliance 2023; 6:e202201889. [PMID: 37137707 PMCID: PMC10156609 DOI: 10.26508/lsa.202201889] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Revised: 04/20/2023] [Accepted: 04/21/2023] [Indexed: 05/05/2023] Open
Abstract
Recursive splicing is a non-canonical splicing mechanism in which an intron is removed in segments via multiple splicing reactions. Relatively few recursive splice sites have been identified with high confidence in human introns, and more comprehensive analyses are needed to better characterize where recursive splicing happens and whether or not it has a regulatory function. In this study, we use an unbiased approach using intron lariats to search for recursive splice sites in constitutive introns and alternative exons in the human transcriptome. We find evidence for recursive splicing in a broader range of intron sizes than previously reported and detail a new location for recursive splicing at the distal ends of cassette exons. In addition, we identify evidence for the conservation of these recursive splice sites among higher vertebrates and the use of these sites to influence alternative exon exclusion. Together, our data demonstrate the prevalence of recursive splicing and its potential influence on gene expression through alternatively spliced isoforms.
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Affiliation(s)
- Emma R Hoppe
- Computational Biology Program, Public Health Sciences Division, Fred Hutchinson Cancer Center, Seattle, WA, USA
- Basic Sciences Division, Fred Hutchinson Cancer Center, Seattle, WA, USA
- Department of Genome Sciences, University of Washington, Seattle, WA, USA
| | - Dylan B Udy
- Computational Biology Program, Public Health Sciences Division, Fred Hutchinson Cancer Center, Seattle, WA, USA
- Basic Sciences Division, Fred Hutchinson Cancer Center, Seattle, WA, USA
| | - Robert K Bradley
- Computational Biology Program, Public Health Sciences Division, Fred Hutchinson Cancer Center, Seattle, WA, USA
- Basic Sciences Division, Fred Hutchinson Cancer Center, Seattle, WA, USA
- Department of Genome Sciences, University of Washington, Seattle, WA, USA
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6
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Vlasenok M, Margasyuk S, Pervouchine DD. Transcriptome sequencing suggests that pre-mRNA splicing counteracts widespread intronic cleavage and polyadenylation. NAR Genom Bioinform 2023; 5:lqad051. [PMID: 37260513 PMCID: PMC10227441 DOI: 10.1093/nargab/lqad051] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2023] [Revised: 05/09/2023] [Accepted: 05/17/2023] [Indexed: 06/02/2023] Open
Abstract
Alternative splicing (AS) and alternative polyadenylation (APA) are two crucial steps in the post-transcriptional regulation of eukaryotic gene expression. Protocols capturing and sequencing RNA 3'-ends have uncovered widespread intronic polyadenylation (IPA) in normal and disease conditions, where it is currently attributed to stochastic variations in the pre-mRNA processing. Here, we took advantage of the massive amount of RNA-seq data generated by the Genotype Tissue Expression project (GTEx) to simultaneously identify and match tissue-specific expression of intronic polyadenylation sites with tissue-specific splicing. A combination of computational methods including the analysis of short reads with non-templated adenines revealed that APA events are more abundant in introns than in exons. While the rate of IPA in composite terminal exons and skipped terminal exons expectedly correlates with splicing, we observed a considerable fraction of IPA events that lack AS support and attributed them to spliced polyadenylated introns (SPI). We hypothesize that SPIs represent transient byproducts of a dynamic coupling between APA and AS, in which the spliceosome removes the intron while it is being cleaved and polyadenylated. These findings indicate that cotranscriptional pre-mRNA splicing could serve as a rescue mechanism to suppress premature transcription termination at intronic polyadenylation sites.
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Affiliation(s)
- Maria Vlasenok
- Center for Molecular and Cellular Biology, Skolkovo Institute of Science and Technology, Bolshoy Bulvar 30, Moscow 121205, Russia
| | - Sergey Margasyuk
- Center for Molecular and Cellular Biology, Skolkovo Institute of Science and Technology, Bolshoy Bulvar 30, Moscow 121205, Russia
| | - Dmitri D Pervouchine
- Center for Molecular and Cellular Biology, Skolkovo Institute of Science and Technology, Bolshoy Bulvar 30, Moscow 121205, Russia
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7
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Hurtig JE, van Hoof A. An unknown essential function of tRNA splicing endonuclease is linked to the integrated stress response and intron debranching. Genetics 2023; 224:iyad044. [PMID: 36943791 PMCID: PMC10213494 DOI: 10.1093/genetics/iyad044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Revised: 10/31/2022] [Accepted: 03/09/2023] [Indexed: 03/23/2023] Open
Abstract
tRNA splicing endonuclease (TSEN) has a well-characterized role in transfer RNA (tRNA) splicing but also other functions. For yeast TSEN, these other functions include degradation of a subset of mRNAs that encode mitochondrial proteins and an unknown essential function. In this study, we use yeast genetics to characterize the unknown tRNA-independent function(s) of TSEN. Using a high-copy suppressor screen, we found that sen2 mutants can be suppressed by overexpression of SEN54. This effect was seen both for tRNA-dependent and tRNA-independent functions indicating that SEN54 is a general suppressor of sen2, likely through structural stabilization. A spontaneous suppressor screen identified mutations in the intron-debranching enzyme, Dbr1, as tRNA splicing-independent suppressors. Transcriptome analysis showed that sen2 mutation activates the Gcn4 stress response. These Gcn4 target transcripts decreased considerably in the sen2 dbr1 double mutant. We propose that Dbr1 and TSEN may compete for a shared substrate, which TSEN normally processes into an essential RNA, while Dbr1 initiates its degradation. These data provide further insight into the essential function(s) of TSEN. Importantly, single amino acid mutations in TSEN cause the generally fatal neuronal disease pontocerebellar hypoplasia (PCH). The mechanism by which defects in TSEN cause this disease is unknown, and our results reveal new possible mechanisms.
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Affiliation(s)
- Jennifer E Hurtig
- Microbiology and Molecular Genetics, The University of Texas Health Science Center at Houston, Houston, TX 77030, USA
| | - Ambro van Hoof
- Microbiology and Molecular Genetics, The University of Texas Health Science Center at Houston, Houston, TX 77030, USA
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8
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Webster SF, Ghalei H. Maturation of small nucleolar RNAs: from production to function. RNA Biol 2023; 20:715-736. [PMID: 37796118 PMCID: PMC10557570 DOI: 10.1080/15476286.2023.2254540] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/28/2023] [Indexed: 10/06/2023] Open
Abstract
Small Nucleolar RNAs (snoRNAs) are an abundant group of non-coding RNAs with well-defined roles in ribosomal RNA processing, folding and chemical modification. Besides their classic roles in ribosome biogenesis, snoRNAs are also implicated in several other cellular activities including regulation of splicing, transcription, RNA editing, cellular trafficking, and miRNA-like functions. Mature snoRNAs must undergo a series of processing steps tightly regulated by transiently associating factors and coordinated with other cellular processes including transcription and splicing. In addition to their mature forms, snoRNAs can contribute to gene expression regulation through their derivatives and degradation products. Here, we review the current knowledge on mechanisms of snoRNA maturation, including the different pathways of processing, and the regulatory mechanisms that control snoRNA levels and complex assembly. We also discuss the significance of studying snoRNA maturation, highlight the gaps in the current knowledge and suggest directions for future research in this area.
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Affiliation(s)
- Sarah F. Webster
- Biochemistry, Cell, and Developmental Biology Graduate Program, Emory University, Atlanta, Georgia, USA
- Department of Biochemistry, Emory University, Atlanta, Georgia, USA
| | - Homa Ghalei
- Department of Biochemistry, Emory University, Atlanta, Georgia, USA
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9
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de Rooij LA, Mastebroek DJ, ten Voorde N, van der Wall E, van Diest PJ, Moelans CB. The microRNA Lifecycle in Health and Cancer. Cancers (Basel) 2022; 14:cancers14235748. [PMID: 36497229 PMCID: PMC9736740 DOI: 10.3390/cancers14235748] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Revised: 11/19/2022] [Accepted: 11/21/2022] [Indexed: 11/24/2022] Open
Abstract
MicroRNAs (miRNAs) are small non-coding RNAs of ~22 nucleotides that regulate gene expression at the post-transcriptional level. They can bind to around 60% of all protein-coding genes with an average of 200 targets per miRNA, indicating their important function within physiological and pathological cellular processes. miRNAs can be quickly produced in high amounts through canonical and non-canonical pathways that involve a multitude of steps and proteins. In cancer, miRNA biogenesis, availability and regulation of target expression can be altered to promote tumour progression. This can be due to genetic causes, such as single nucleotide polymorphisms, epigenetic changes, differences in host gene expression, or chromosomal remodelling. Alternatively, post-transcriptional changes in miRNA stability, and defective or absent components and mediators of the miRNA-induced silencing complex can lead to altered miRNA function. This review provides an overview of the current knowledge on the lifecycle of miRNAs in health and cancer. Understanding miRNA function and regulation is fundamental prior to potential future application of miRNAs as cancer biomarkers.
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Affiliation(s)
- Laura Adriana de Rooij
- Department of Pathology, University Medical Center Utrecht, Utrecht University, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands
- Correspondence: ; Tel.: +31-887-556-557
| | - Dirk Jan Mastebroek
- Department of Pathology, University Medical Center Utrecht, Utrecht University, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands
| | - Nicky ten Voorde
- Department of Pathology, University Medical Center Utrecht, Utrecht University, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands
| | - Elsken van der Wall
- Department of Medical Oncology, University Medical Center Utrecht, Utrecht University, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands
| | - Paul Joannes van Diest
- Department of Pathology, University Medical Center Utrecht, Utrecht University, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands
| | - Cathy Beatrice Moelans
- Department of Pathology, University Medical Center Utrecht, Utrecht University, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands
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10
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Robic A, Cerutti C, Demars J, Kühn C. From the comparative study of a circRNA originating from an mammalian ATXN2L intron to understanding the genesis of intron lariat-derived circRNAs. Biochim Biophys Acta Gene Regul Mech 2022; 1865:194815. [PMID: 35513260 DOI: 10.1016/j.bbagrm.2022.194815] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2022] [Revised: 04/12/2022] [Accepted: 04/14/2022] [Indexed: 06/14/2023]
Abstract
Circular intronic RNAs (ciRNAs) are still unexplored regarding mechanisms for their emergence. We considered the ATXN2L intron lariat-derived circular RNA (ciRNA-ATXN2L) as an opportunity to conduct a cross-species examination of ciRNA genesis. To this end, we investigated 207 datasets from 4 tissues and from 13 mammalian species. While in eight species, ciRNA-ATXN2L was never detected, in pigs and rabbits, ciRNA-ATXN2L was expressed in all tissues and sometimes at very high levels. Bovine tissues were an intermediate case and in macaques and cats, only ciRNA-ATXN2L traces were detected. The pattern of ciRNA-ATXN2L restricted to only five species is not related to a particular evolution of intronic sequences. To empower our analysis, we considered 221 additional introns including 80 introns where a lariat-derived ciRNA was previously described. The primary driver of micro-ciRNA genesis (< 155 nt as ciRNA-ATXN2L) appears to be the absence of a canonical "A" (i.e. a "tnA" located in the usual branching region) to build the lariat around this adenosine. The balance between available "non canonical-A" (no ciRNA genesis) and "non-A" (ciRNA genesis) for use as a branch point to build the lariat could modify the expression level of ciRNA-ATXN2L. In addition, the rare localization of the 2'-5' bond in an open RNA secondary structure could also negatively affect the lifetime of ciRNAs (macaque ciRNA-ATXN2L). Our analyses suggest that ciRNA-ATXN2L is likely a functionless splice remnant. This study provides a better understanding of the ciRNAs origin, especially drivers for micro ciRNA genesis.
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Affiliation(s)
- Annie Robic
- GenPhySE, Université de Toulouse, INRAE, ENVT, 31326 Castanet Tolosan, France.
| | - Chloé Cerutti
- GenPhySE, Université de Toulouse, INRAE, ENVT, 31326 Castanet Tolosan, France.
| | - Julie Demars
- GenPhySE, Université de Toulouse, INRAE, ENVT, 31326 Castanet Tolosan, France.
| | - Christa Kühn
- Institute of Genome Biology, Research Institute for Farm Animal Biology (FBN), 18196 Dummerstorf, Germany; Faculty of Agricultural and Environmental Sciences, University of Rostock, 18059 Rostock, Germany.
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Xu X, Yang X, Liu X, Bi Y, Kong P, Wang Y, Cheng X, Xi Y. The Role of DBR1 as a Candidate Prognosis Biomarker in Esophageal Squamous Cell Carcinoma. Technol Cancer Res Treat 2022; 21:15330338221083105. [PMID: 35244467 PMCID: PMC8902023 DOI: 10.1177/15330338221083105] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Aims: Esophageal squamous cell carcinoma (ESCC) is one of the most prevalent malignancies with unfavorable clinical outcomes and limited therapeutic methods. As a key enzyme in RNA metabolism, debranching RNA Lariats 1 (DBR1) is involved in intron turnover and biogenesis of noncoding RNA. Although cancer cells often show disorder of nucleic acid metabolism, it is unclear whether DBR1 has any effect on the carcinogenesis and progression of ESCC. Methods: Here we detected DBR1 expression in 112 ESCC samples by immunohistochemistry and analyzed its correlation with clinical parameters and survival. Results: DBR1 is mainly located in the nucleus of ESCC tissue. And DBR1 was associated with several malignant clinical features in patients, including tumor location (χ2 = 9.687, P = .021), pathologic T stage (χ2 = 5.771, P = .016), lymph node metastasis (χ2 = 8.215, P = .004) and N classification (χ2 = 10.066, P = .018). Moreover, Kaplan-Meier analysis showed that ESCC patients harboring lower DBR1 expression had a worse prognosis in comparison with those with higher DBR1 expression (P = .005). Univariate and multivariate Cox proportional hazards regression analyses indicated that decreased DBR1 might act as an independent predictor of poor prognosis for ESCC patients. Conclusion: Abnormal RNA metabolism might play a critical role in promoting the progression of ESCC, and DBR1 may be a promising potential biomarker for predicting the prognosis of ESCC patients.
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Affiliation(s)
- Xiaoqin Xu
- Key Laboratory of Cellular Physiology, Ministry of Education, 74648Shanxi Medical University, Taiyuan, Shanxi, People's Republic of China.,Shanxi Cancer Hospital, Taiyuan, Shanxi, People's Republic of China
| | - Xin Yang
- Key Laboratory of Cellular Physiology, Ministry of Education, 74648Shanxi Medical University, Taiyuan, Shanxi, People's Republic of China
| | - Xue Liu
- Key Laboratory of Cellular Physiology, Ministry of Education, 74648Shanxi Medical University, Taiyuan, Shanxi, People's Republic of China
| | - Yanghui Bi
- Key Laboratory of Cellular Physiology, Ministry of Education, 74648Shanxi Medical University, Taiyuan, Shanxi, People's Republic of China
| | - Pengzhou Kong
- Key Laboratory of Cellular Physiology, Ministry of Education, 74648Shanxi Medical University, Taiyuan, Shanxi, People's Republic of China
| | - Yanqiang Wang
- Key Laboratory of Cellular Physiology, Ministry of Education, 74648Shanxi Medical University, Taiyuan, Shanxi, People's Republic of China
| | - Xiaolong Cheng
- Key Laboratory of Cellular Physiology, Ministry of Education, 74648Shanxi Medical University, Taiyuan, Shanxi, People's Republic of China
| | - Yanfeng Xi
- Shanxi Cancer Hospital, Taiyuan, Shanxi, People's Republic of China
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Fekete E, Pénzes F, Ág N, Scazzocchio C, Flipphi M, Karaffa L. Internally Symmetrical Stwintrons and Related Canonical Introns in Hypoxylaceae Species. J Fungi (Basel) 2021; 7:710. [PMID: 34575748 DOI: 10.3390/jof7090710] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Revised: 08/26/2021] [Accepted: 08/26/2021] [Indexed: 01/01/2023] Open
Abstract
Spliceosomal introns are pervasive in eukaryotes. Intron gains and losses have occurred throughout evolution, but the origin of new introns is unclear. Stwintrons are complex intervening sequences where one of the sequence elements (5′-donor, lariat branch point element or 3′-acceptor) necessary for excision of a U2 intron (external intron) is itself interrupted by a second (internal) U2 intron. In Hypoxylaceae, a family of endophytic fungi, we uncovered scores of donor-disrupted stwintrons with striking sequence similarity among themselves and also with canonical introns. Intron–exon structure comparisons suggest that these stwintrons have proliferated within diverging taxa but also give rise to proliferating canonical introns in some genomes. The proliferated (stw)introns have integrated seamlessly at novel gene positions. The recently proliferated (stw)introns appear to originate from a conserved ancestral stwintron characterised by terminal inverted repeats (45–55 nucleotides), a highly symmetrical structure that may allow the formation of a double-stranded intron RNA molecule. No short tandem duplications flank the putatively inserted intervening sequences, which excludes a DNA transposition-based mechanism of proliferation. It is tempting to suggest that this highly symmetrical structure may have a role in intron proliferation by (an)other mechanism(s).
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Li X, Zhang JL, Lei YN, Liu XQ, Xue W, Zhang Y, Nan F, Gao X, Zhang J, Wei J, Yang L, Chen LL. Linking circular intronic RNA degradation and function in transcription by RNase H1. Sci China Life Sci 2021; 64:1795-809. [PMID: 34453665 DOI: 10.1007/s11427-021-1993-6] [Citation(s) in RCA: 36] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/14/2021] [Accepted: 08/15/2021] [Indexed: 01/22/2023]
Abstract
Circular intronic RNAs (ciRNAs) escaping from DBR1 debranching of intron lariats are co-transcriptionally produced from pre-mRNA splicing, but their turnover and mechanism of action have remained elusive. We report that RNase H1 degrades a subgroup of ciRNAs in human cells. Many ciRNAs contain high GC% and tend to form DNA:RNA hybrids (R-loops) for RNase H1 cleavage, a process that appears to promote Pol II transcriptional elongation at ciRNA-producing loci. One ciRNA, ciankrd52, shows a stronger ability of R-loop formation than that of its cognate pre-mRNA by maintaining a locally open RNA structure in vitro. This allows the release of pre-mRNA from R-loops by ci-ankrd52 replacement and subsequent ciRNA removal via RNase H1 for efficient transcriptional elongation. We propose that such an R-loop dependent ciRNA degradation likely represents a mechanism that on one hand limits ciRNA accumulation by recruiting RNase H1 and on the other hand resolves R-loops for transcriptional elongation at some GC-rich ciRNA-producing loci.
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Kataoka N, Matsumoto E, Masaki S. Mechanistic Insights of Aberrant Splicing with Splicing Factor Mutations Found in Myelodysplastic Syndromes. Int J Mol Sci 2021; 22:ijms22157789. [PMID: 34360561 PMCID: PMC8346168 DOI: 10.3390/ijms22157789] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2021] [Revised: 07/19/2021] [Accepted: 07/19/2021] [Indexed: 12/22/2022] Open
Abstract
Pre-mRNA splicing is an essential process for gene expression in higher eukaryotes, which requires a high order of accuracy. Mutations in splicing factors or regulatory elements in pre-mRNAs often result in many human diseases. Myelodysplastic syndrome (MDS) is a heterogeneous group of chronic myeloid neoplasms characterized by many symptoms and a high risk of progression to acute myeloid leukemia. Recent findings indicate that mutations in splicing factors represent a novel class of driver mutations in human cancers and affect about 50% of Myelodysplastic syndrome (MDS) patients. Somatic mutations in MDS patients are frequently found in genes SF3B1, SRSF2, U2AF1, and ZRSR2. Interestingly, they are involved in the recognition of 3' splice sites and exons. It has been reported that mutations in these splicing regulators result in aberrant splicing of many genes. In this review article, we first describe molecular mechanism of pre-mRNA splicing as an introduction and mainly focus on those four splicing factors to describe their mutations and their associated aberrant splicing patterns.
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Affiliation(s)
- Naoyuki Kataoka
- Laboratory of Cellular Biochemistry, Department of Animal Resource Sciences, Graduate School of Agriculture and Life Sciences, The University of Tokyo, Tokyo 113-8657, Japan;
- Correspondence: ; Tel.: +81-3-5841-5372; Fax: +81-3-5841-8014
| | - Eri Matsumoto
- Laboratory of Cellular Biochemistry, Department of Animal Resource Sciences, Graduate School of Agriculture and Life Sciences, The University of Tokyo, Tokyo 113-8657, Japan;
| | - So Masaki
- Laboratory of Molecular Medicinal Science, Department of Pharmaceutical Sciences, Ritsumeikan University, Shiga 525-8577, Japan;
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