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Su Y, Wu J, Chen W, Shan J, Chen D, Zhu G, Ge S, Liu Y. Spliceosomal snRNAs, the Essential Players in pre-mRNA Processing in Eukaryotic Nucleus: From Biogenesis to Functions and Spatiotemporal Characteristics. Adv Biol (Weinh) 2024; 8:e2400006. [PMID: 38797893 DOI: 10.1002/adbi.202400006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2024] [Revised: 04/30/2024] [Indexed: 05/29/2024]
Abstract
Spliceosomal small nuclear RNAs (snRNAs) are a fundamental class of non-coding small RNAs abundant in the nucleoplasm of eukaryotic cells, playing a crucial role in splicing precursor messenger RNAs (pre-mRNAs). They are transcribed by DNA-dependent RNA polymerase II (Pol II) or III (Pol III), and undergo subsequent processing and 3' end cleavage to become mature snRNAs. Numerous protein factors are involved in the transcription initiation, elongation, termination, splicing, cellular localization, and terminal modification processes of snRNAs. The transcription and processing of snRNAs are regulated spatiotemporally by various mechanisms, and the homeostatic balance of snRNAs within cells is of great significance for the growth and development of organisms. snRNAs assemble with specific accessory proteins to form small nuclear ribonucleoprotein particles (snRNPs) that are the basal components of spliceosomes responsible for pre-mRNA maturation. This article provides an overview of the biological functions, biosynthesis, terminal structure, and tissue-specific regulation of snRNAs.
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Affiliation(s)
- Yuan Su
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Science and Technology, Guangxi University, Nanning, Guangxi, 530004, China
| | - Jiaming Wu
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Science and Technology, Guangxi University, Nanning, Guangxi, 530004, China
| | - Wei Chen
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Science and Technology, Guangxi University, Nanning, Guangxi, 530004, China
| | - Junling Shan
- Department of basic medicine, Guangxi Medical University of Nursing College, Nanning, Guangxi, 530021, China
| | - Dan Chen
- Ruikang Hospital Affiliated to Guangxi University of Chinese Medicine, Nanning, Guangxi, 530011, China
| | - Guangyu Zhu
- Guangxi Medical University Hospital of Stomatology, Nanning, Guangxi, 530021, China
| | - Shengchao Ge
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Science and Technology, Guangxi University, Nanning, Guangxi, 530004, China
| | - Yunfeng Liu
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-bioresources, College of Life Science and Technology, Guangxi University, Nanning, Guangxi, 530004, China
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2
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Wong J, Yellamaty R, Gallante C, Lawrence E, Martelly W, Sharma S. Examining the capacity of human U1 snRNA variants to facilitate pre-mRNA splicing. RNA (NEW YORK, N.Y.) 2024; 30:271-280. [PMID: 38164604 PMCID: PMC10870369 DOI: 10.1261/rna.079892.123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2023] [Accepted: 12/18/2023] [Indexed: 01/03/2024]
Abstract
The human U1 snRNA is encoded by a multigene family consisting of transcribed variants and defective pseudogenes. Many variant U1 (vU1) snRNAs have been demonstrated to not only be transcribed but also processed by the addition of a trimethylated guanosine cap, packaged into snRNPs, and assembled into spliceosomes; however, their capacity to facilitate pre-mRNA splicing has, so far, not been tested. A recent systematic analysis of the human snRNA genes identified 178 U1 snRNA genes that are present in the genome as either tandem arrays or single genes on multiple chromosomes. Of these, 15 were found to be expressed in human tissues and cell lines, although at significantly low levels from their endogenous loci, <0.001% of the canonical U1 snRNA. In this study, we found that placing the variants in the context of the regulatory elements of the RNU1-1 gene improves the expression of many variants to levels comparable to the canonical U1 snRNA. Application of a previously established HeLa cell-based minigene reporter assay to examine the capacity of the vU1 snRNAs to support pre-mRNA splicing revealed that even though the exogenously expressed variant snRNAs were enriched in the nucleus, only a few had a measurable effect on splicing.
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Affiliation(s)
- Jason Wong
- Department of Basic Medical Sciences, College of Medicine-Phoenix, University of Arizona, Phoenix, Arizona 85004, USA
| | - Ryan Yellamaty
- Department of Basic Medical Sciences, College of Medicine-Phoenix, University of Arizona, Phoenix, Arizona 85004, USA
| | - Christina Gallante
- Department of Basic Medical Sciences, College of Medicine-Phoenix, University of Arizona, Phoenix, Arizona 85004, USA
| | - Ethan Lawrence
- Department of Basic Medical Sciences, College of Medicine-Phoenix, University of Arizona, Phoenix, Arizona 85004, USA
| | - William Martelly
- Department of Basic Medical Sciences, College of Medicine-Phoenix, University of Arizona, Phoenix, Arizona 85004, USA
| | - Shalini Sharma
- Department of Basic Medical Sciences, College of Medicine-Phoenix, University of Arizona, Phoenix, Arizona 85004, USA
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3
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Girardini KN, Olthof AM, Kanadia RN. Introns: the "dark matter" of the eukaryotic genome. Front Genet 2023; 14:1150212. [PMID: 37260773 PMCID: PMC10228655 DOI: 10.3389/fgene.2023.1150212] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2023] [Accepted: 04/28/2023] [Indexed: 06/02/2023] Open
Abstract
The emergence of introns was a significant evolutionary leap that is a major distinguishing feature between prokaryotic and eukaryotic genomes. While historically introns were regarded merely as the sequences that are removed to produce spliced transcripts encoding functional products, increasingly data suggests that introns play important roles in the regulation of gene expression. Here, we use an intron-centric lens to review the role of introns in eukaryotic gene expression. First, we focus on intron architecture and how it may influence mechanisms of splicing. Second, we focus on the implications of spliceosomal snRNAs and their variants on intron splicing. Finally, we discuss how the presence of introns and the need to splice them influences transcription regulation. Despite the abundance of introns in the eukaryotic genome and their emerging role regulating gene expression, a lot remains unexplored. Therefore, here we refer to introns as the "dark matter" of the eukaryotic genome and discuss some of the outstanding questions in the field.
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Affiliation(s)
- Kaitlin N. Girardini
- Physiology and Neurobiology Department, University of Connecticut, Storrs, CT, United States
| | - Anouk M. Olthof
- Physiology and Neurobiology Department, University of Connecticut, Storrs, CT, United States
- Department of Cellular and Molecular Medicine, University of Copenhagen, Copenhagen, Denmark
| | - Rahul N. Kanadia
- Physiology and Neurobiology Department, University of Connecticut, Storrs, CT, United States
- Institute for Systems Genomics, University of Connecticut, Storrs, CT, United States
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4
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Martí E, Milani D, Bardella VB, Albuquerque L, Song H, Palacios-Gimenez OM, Cabral-de-Mello DC. Cytogenomic analysis unveils mixed molecular evolution and recurrent chromosomal rearrangements shaping the multigene families on Schistocerca grasshopper genomes. Evolution 2021; 75:2027-2041. [PMID: 34155627 DOI: 10.1111/evo.14287] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Revised: 05/11/2021] [Accepted: 05/26/2021] [Indexed: 11/26/2022]
Abstract
Multigene families are essential components of eukaryotic genomes and play key roles either structurally and functionally. Their modes of evolution remain elusive even in the era of genomics, because multiple multigene family sequences coexist in genomes, particularly in large repetitive genomes. Here, we investigate how the multigene families 18S rDNA, U2 snDNA, and H3 histone evolved in 10 species of Schistocerca grasshoppers with very large and repeat-enriched genomes. Using sequenced genomes and fluorescence in situ hybridization mapping, we find substantial differences between species, including the number of chromosomal clusters, changes in sequence abundance and nucleotide composition, pseudogenization, and association with transposable elements (TEs). The intragenomic analysis of Schistocerca gregaria using long-read sequencing and genome assembly unveils conservation for H3 histone and recurrent pseudogenization for 18S rDNA and U2 snDNA, likely promoted by association with TEs and sequence truncation. Remarkably, TEs were frequently associated with truncated copies, were also among the most abundant in the genome, and revealed signatures of recent activity. Our findings suggest a combined effect of concerted and birth-and-death models driving the evolution of multigene families in Schistocerca over the last 8 million years, and the occurrence of intra- and interchromosomal rearrangements shaping their chromosomal distribution. Despite the conserved karyotype in Schistocerca, our analysis highlights the extensive reorganization of repetitive DNAs in Schistocerca, contributing to the advance of comparative genomics for this important grasshopper genus.
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Affiliation(s)
- Emiliano Martí
- Departamento de Biologia Geral e Aplicada, UNESP - Univ Estadual Paulista, Instituto de Biociências/IB, Rio Claro, 13506-900, Brazil
| | - Diogo Milani
- Departamento de Biologia Geral e Aplicada, UNESP - Univ Estadual Paulista, Instituto de Biociências/IB, Rio Claro, 13506-900, Brazil
| | - Vanessa B Bardella
- Departamento de Biologia Geral e Aplicada, UNESP - Univ Estadual Paulista, Instituto de Biociências/IB, Rio Claro, 13506-900, Brazil
| | - Lucas Albuquerque
- Departamento de Biologia Geral e Aplicada, UNESP - Univ Estadual Paulista, Instituto de Biociências/IB, Rio Claro, 13506-900, Brazil
| | - Hojun Song
- Department of Entomology, Texas A&M University, College Station, Texas, 77843
| | - Octavio M Palacios-Gimenez
- Department of Organismal Biology - Systematic Biology, Evolutionary Biology Centre, Uppsala University, Uppsala, SE-75236, Sweden.,Population Ecology Group, Institute of Ecology and Evolution, Friedrich Schiller University Jena, Jena, DE-07743, Germany
| | - Diogo C Cabral-de-Mello
- Departamento de Biologia Geral e Aplicada, UNESP - Univ Estadual Paulista, Instituto de Biociências/IB, Rio Claro, 13506-900, Brazil
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5
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Molinnus D, Drinic A, Iken H, Kröger N, Zinser M, Smeets R, Köpf M, Kopp A, Schöning MJ. Towards a flexible electrochemical biosensor fabricated from biocompatible Bombyx mori silk. Biosens Bioelectron 2021; 183:113204. [PMID: 33836429 DOI: 10.1016/j.bios.2021.113204] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2020] [Revised: 03/22/2021] [Accepted: 03/24/2021] [Indexed: 12/13/2022]
Abstract
In modern days, there is an increasing relevance of and demand for flexible and biocompatible sensors for in-vivo and epidermal applications. One promising strategy is the implementation of biological (natural) polymers, which offer new opportunities for flexible biosensor devices due to their high biocompatibility and adjustable biodegradability. As a proof-of-concept experiment, a biosensor was fabricated by combining thin- (for Pt working- and counter electrode) and thick-film (for Ag/AgCl quasi-reference electrode) technologies: The biosensor consists of a fully bio-based and biodegradable fibroin substrate derived from silk fibroin of the silkworm Bombyx mori combined with immobilized enzyme glucose oxidase. The flexible glucose biosensor is encapsulated by a biocompatible silicon rubber which is certificated for a safe use onto human skin. Characterization of the sensor set-up is exemplarily demonstrated by glucose measurements in buffer and Ringer's solution, while the stability of the quasi-reference electrode has been investigated versus a commercial Ag/AgCl reference electrode. Repeated bending studies validated the mechanical properties of the electrode structures. The cross-sensitivity of the biosensor against ascorbic acid, noradrenaline and adrenaline was investigated, too. Additionally, biocompatibility and degradation tests of the silk fibroin with and without thin-film platinum electrodes were carried out.
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Affiliation(s)
- Denise Molinnus
- Institute of Nano- and Biotechnologies (INB), FH Aachen, Campus Jülich, Heinrich-Mußmann-Strasse 1, 52428, Jülich, Germany
| | - Aleksander Drinic
- Fibrothelium GmbH, TRIWO Technopark Aachen, Philipsstr. 8, 52068, Aachen, Germany
| | - Heiko Iken
- Institute of Nano- and Biotechnologies (INB), FH Aachen, Campus Jülich, Heinrich-Mußmann-Strasse 1, 52428, Jülich, Germany
| | - Nadja Kröger
- Department of Plastic, Reconstructive and Aesthetic Surgery, University Hospital of Cologne, Kerpener Str. 62, 50937, Cologne, Germany
| | - Max Zinser
- Department of Plastic, Reconstructive and Aesthetic Surgery, University Hospital of Cologne, Kerpener Str. 62, 50937, Cologne, Germany
| | - Ralf Smeets
- Department of Oral and Maxillofacial Surgery, Division of Regenerative Orofacial Medicine, University Medical Center Hamburg-Eppendorf, Martinistraße 52, Hamburg, Germany
| | - Marius Köpf
- Fibrothelium GmbH, TRIWO Technopark Aachen, Philipsstr. 8, 52068, Aachen, Germany
| | - Alexander Kopp
- Fibrothelium GmbH, TRIWO Technopark Aachen, Philipsstr. 8, 52068, Aachen, Germany
| | - Michael J Schöning
- Institute of Nano- and Biotechnologies (INB), FH Aachen, Campus Jülich, Heinrich-Mußmann-Strasse 1, 52428, Jülich, Germany; Forschungszentrum Jülich GmbH, Institute of Biological Information Processing (IBI-3), Wilhelm-Johnen-Strasse 6, 52425, Jülich, Germany.
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6
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Vazquez-Arango P, Vowles J, Browne C, Hartfield E, Fernandes H, Mandefro B, Sareen D, James W, Wade-Martins R, Cowley SA, Murphy S, O'Reilly D. Variant U1 snRNAs are implicated in human pluripotent stem cell maintenance and neuromuscular disease. Nucleic Acids Res 2016; 44:10960-10973. [PMID: 27536002 PMCID: PMC5159530 DOI: 10.1093/nar/gkw711] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2016] [Revised: 08/01/2016] [Accepted: 08/04/2016] [Indexed: 02/06/2023] Open
Abstract
The U1 small nuclear (sn)RNA (U1) is a multifunctional ncRNA, known for its pivotal role in pre-mRNA splicing and regulation of RNA 3' end processing events. We recently demonstrated that a new class of human U1-like snRNAs, the variant (v)U1 snRNAs (vU1s), also participate in pre-mRNA processing events. In this study, we show that several human vU1 genes are specifically upregulated in stem cells and participate in the regulation of cell fate decisions. Significantly, ectopic expression of vU1 genes in human skin fibroblasts leads to increases in levels of key pluripotent stem cell mRNA markers, including NANOG and SOX2. These results reveal an important role for vU1s in the control of key regulatory networks orchestrating the transitions between stem cell maintenance and differentiation. Moreover, vU1 expression varies inversely with U1 expression during differentiation and cell re-programming and this pattern of expression is specifically de-regulated in iPSC-derived motor neurons from Spinal Muscular Atrophy (SMA) type 1 patient's. Accordingly, we suggest that an imbalance in the vU1/U1 ratio, rather than an overall reduction in Uridyl-rich (U)-snRNAs, may contribute to the specific neuromuscular disease phenotype associated with SMA.
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Affiliation(s)
- Pilar Vazquez-Arango
- University of Oxford, Sir William Dunn School of Pathology, South Parks Road, Oxford, OX1 3RE, UK
| | - Jane Vowles
- University of Oxford, Sir William Dunn School of Pathology, South Parks Road, Oxford, OX1 3RE, UK,Oxford Parkinson's Disease Centre, University of Oxford, Oxford, UK
| | - Cathy Browne
- University of Oxford, Sir William Dunn School of Pathology, South Parks Road, Oxford, OX1 3RE, UK
| | - Elizabeth Hartfield
- Oxford Parkinson's Disease Centre, University of Oxford, Oxford, UK,Oxford Parkinson's Disease Centre, Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK
| | - Hugo J. R. Fernandes
- Oxford Parkinson's Disease Centre, University of Oxford, Oxford, UK,Oxford Parkinson's Disease Centre, Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK
| | - Berhan Mandefro
- Cedars-Sinai Medical Center, Board of Governors-Regenerative Medicine Institute and Department of Biomedical Sciences, 8700 Beverly Blvd, AHSP A8418, Los Angeles, CA 90048, USA,iPSC Core, The David and Janet Polak Foundation Stem Cell Core Laboratory, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA
| | - Dhruv Sareen
- Cedars-Sinai Medical Center, Board of Governors-Regenerative Medicine Institute and Department of Biomedical Sciences, 8700 Beverly Blvd, AHSP A8418, Los Angeles, CA 90048, USA,iPSC Core, The David and Janet Polak Foundation Stem Cell Core Laboratory, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA
| | - William James
- University of Oxford, Sir William Dunn School of Pathology, South Parks Road, Oxford, OX1 3RE, UK
| | - Richard Wade-Martins
- Oxford Parkinson's Disease Centre, University of Oxford, Oxford, UK,Oxford Parkinson's Disease Centre, Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK
| | - Sally A. Cowley
- University of Oxford, Sir William Dunn School of Pathology, South Parks Road, Oxford, OX1 3RE, UK,Oxford Parkinson's Disease Centre, University of Oxford, Oxford, UK
| | - Shona Murphy
- University of Oxford, Sir William Dunn School of Pathology, South Parks Road, Oxford, OX1 3RE, UK
| | - Dawn O'Reilly
- University of Oxford, Sir William Dunn School of Pathology, South Parks Road, Oxford, OX1 3RE, UK
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7
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Abstract
Pre-mRNA splicing is a critical step in eukaryotic gene expression that contributes to proteomic, cellular, and developmental complexity. Small nuclear (sn)RNAs are core spliceosomal components; however, the extent to which differential expression of snRNA isoforms regulates splicing is completely unknown. This is partly due to difficulties in the accurate analysis of the spatial and temporal expression patterns of snRNAs. Here, we use high-throughput RNA-sequencing (RNA-seq) data to profile expression of four major snRNAs throughout Drosophila development. This analysis shows that individual isoforms of each snRNA have distinct expression patterns in the embryo, larva, and pharate adult stages. Expression of these isoforms is more heterogeneous during embryogenesis; as development progresses, a single isoform from each snRNA subtype gradually dominates expression. Despite the lack of stable snRNA orthologous groups during evolution, this developmental switching of snRNA isoforms also occurs in distantly related vertebrate species, such as Xenopus, mouse, and human. Our results indicate that expression of snRNA isoforms is regulated and lays the foundation for functional studies of individual snRNA isoforms.
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8
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Guiro J, O'Reilly D. Insights into the U1 small nuclear ribonucleoprotein complex superfamily. WILEY INTERDISCIPLINARY REVIEWS-RNA 2014; 6:79-92. [DOI: 10.1002/wrna.1257] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/19/2014] [Revised: 06/17/2014] [Accepted: 07/14/2014] [Indexed: 12/12/2022]
Affiliation(s)
- J Guiro
- Institute of Biosciences; University of Sao Paulo; Sao Paulo Brazil
| | - D O'Reilly
- Sir William Dunn School of Pathology; Oxford United Kingdom
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9
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Matylla-Kulinska K, Tafer H, Weiss A, Schroeder R. Functional repeat-derived RNAs often originate from retrotransposon-propagated ncRNAs. WILEY INTERDISCIPLINARY REVIEWS-RNA 2014; 5:591-600. [PMID: 25045147 PMCID: PMC4233971 DOI: 10.1002/wrna.1243] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/20/2013] [Revised: 04/15/2014] [Accepted: 04/22/2014] [Indexed: 12/19/2022]
Abstract
The human genome is scattered with repetitive sequences, and the ENCODE project revealed that 60–70% of the genomic DNA is transcribed into RNA. As a consequence, the human transcriptome contains a large portion of repeat-derived RNAs (repRNAs). Here, we present a hypothesis for the evolution of novel functional repeat-derived RNAs from non-coding RNAs (ncRNAs) by retrotransposition. Upon amplification, the ncRNAs can diversify in sequence and subsequently evolve new activities, which can result in novel functions. Non-coding transcripts derived from highly repetitive regions can therefore serve as a reservoir for the evolution of novel functional RNAs. We base our hypothetical model on observations reported for short interspersed nuclear elements derived from 7SL RNA and tRNAs, α satellites derived from snoRNAs and SL RNAs derived from U1 small nuclear RNA. Furthermore, we present novel putative human repeat-derived ncRNAs obtained by the comparison of the Dfam and Rfam databases, as well as several examples in other species. We hypothesize that novel functional ncRNAs can derive also from other repetitive regions and propose Genomic SELEX as a tool for their identification.
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Affiliation(s)
- Katarzyna Matylla-Kulinska
- Department of Biochemistry and Cell Biology, Max F. Perutz Laboratories, University of Vienna, Vienna, Austria
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10
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Somarelli JA, Mesa A, Rodriguez CE, Sharma S, Herrera RJ. U1 small nuclear RNA variants differentially form ribonucleoprotein particles in vitro. Gene 2014; 540:11-15. [PMID: 24583175 DOI: 10.1016/j.gene.2014.02.054] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2014] [Revised: 02/19/2014] [Accepted: 02/25/2014] [Indexed: 10/25/2022]
Abstract
The U1 small nuclear (sn)RNA participates in splicing of pre-mRNAs by recognizing and binding to 5' splice sites at exon/intron boundaries. U1 snRNAs associate with 5' splice sites in the form of ribonucleoprotein particles (snRNPs) that are comprised of the U1 snRNA and 10 core components, including U1A, U1-70K, U1C and the 'Smith antigen', or Sm, heptamer. The U1 snRNA is highly conserved across a wide range of taxa; however, a number of reports have identified the presence of expressed U1-like snRNAs in multiple species, including humans. While numerous U1-like molecules have been shown to be expressed, it is unclear whether these variant snRNAs have the capacity to form snRNPs and participate in splicing. The purpose of the present study was to further characterize biochemically the ability of previously identified human U1-like variants to form snRNPs and bind to U1 snRNP proteins. A bioinformatics analysis provided support for the existence of multiple expressed variants. In vitro gel shift assays, competition assays, and immunoprecipitations (IPs) revealed that the variants formed high molecular weight assemblies to varying degrees and associated with core U1 snRNP proteins to a lesser extent than the canonical U1 snRNA. Together, these data suggest that the human U1 snRNA variants analyzed here are unable to efficiently bind U1 snRNP proteins. The current work provides additional biochemical insights into the ability of the variants to assemble into snRNPs.
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Affiliation(s)
- Jason A Somarelli
- Center for RNA Biology and Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC
| | - Annia Mesa
- Department of Biological Sciences, Florida International University, Miami, FL
| | - Carol E Rodriguez
- Department of Biological Sciences, Florida International University, Miami, FL
| | - Shalini Sharma
- Department of Basic Medical Sciences, University of Arizona, College of Medicine- Phoenix, Phoenix, AZ
| | - Rene J Herrera
- Human and Molecular Genetics, College of Medicine, Florida International University, Miami, FL
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11
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Jia Y, Mu JC, Ackerman SL. Mutation of a U2 snRNA gene causes global disruption of alternative splicing and neurodegeneration. Cell 2012; 148:296-308. [PMID: 22265417 DOI: 10.1016/j.cell.2011.11.057] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2011] [Revised: 08/06/2011] [Accepted: 11/08/2011] [Indexed: 12/30/2022]
Abstract
Although uridine-rich small nuclear RNAs (U-snRNAs) are essential for pre-mRNA splicing, little is known regarding their function in the regulation of alternative splicing or of the biological consequences of their dysfunction in mammals. Here, we demonstrate that mutation of Rnu2-8, one of the mouse multicopy U2 snRNA genes, causes ataxia and neurodegeneration. Coincident with the observed pathology, the level of mutant U2 RNAs was highest in the cerebellum and increased after granule neuron maturation. Furthermore, neuron loss was strongly dependent on the dosage of mutant and wild-type snRNA genes. Comprehensive transcriptome analysis identified a group of alternative splicing events, including the splicing of small introns, which were disrupted in the mutant cerebellum. Our results suggest that the expression of mammalian U2 snRNA genes, previously presumed to be ubiquitous, is spatially and temporally regulated, and dysfunction of a single U2 snRNA causes neuron degeneration through distortion of pre-mRNA splicing.
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Affiliation(s)
- Yichang Jia
- Howard Hughes Medical Institute and The Jackson Laboratory, 600 Main Street, Bar Harbor, ME 04609, USA
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12
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Marz M, Kirsten T, Stadler PF. Evolution of spliceosomal snRNA genes in metazoan animals. J Mol Evol 2009; 67:594-607. [PMID: 19030770 DOI: 10.1007/s00239-008-9149-6] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2008] [Accepted: 07/14/2008] [Indexed: 11/28/2022]
Abstract
While studies of the evolutionary histories of protein families are commonplace, little is known on noncoding RNAs beyond microRNAs and some snoRNAs. Here we investigate in detail the evolutionary history of the nine spliceosomal snRNA families (U1, U2, U4, U5, U6, U11, U12, U4atac, and U6atac) across the completely or partially sequenced genomes of metazoan animals. Representatives of the five major spliceosomal snRNAs were found in all genomes. None of the minor splicesomal snRNAs were detected in nematodes or in the shotgun traces of Oikopleura dioica, while in all other animal genomes at most one of them is missing. Although snRNAs are present in multiple copies in most genomes, distinguishable paralogue groups are not stable over long evolutionary times, although they appear independently in several clades. In general, animal snRNA secondary structures are highly conserved, albeit, in particular, U11 and U12 in insects exhibit dramatic variations. An analysis of genomic context of snRNAs reveals that they behave like mobile elements, exhibiting very little syntenic conservation.
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Affiliation(s)
- Manuela Marz
- Bioinformatics Group, Department of Computer Science, University of Leipzig, Härtelstrasse 16-18, 04107 Leipzig, Germany.
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13
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Mount SM, Gotea V, Lin CF, Hernandez K, Makalowski W. Spliceosomal small nuclear RNA genes in 11 insect genomes. RNA (NEW YORK, N.Y.) 2007; 13:5-14. [PMID: 17095541 PMCID: PMC1705759 DOI: 10.1261/rna.259207] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
The removal of introns from the primary transcripts of protein-coding genes is accomplished by the spliceosome, a large macromolecular complex of which small nuclear RNAs (snRNAs) are crucial components. Following the recent sequencing of the honeybee (Apis mellifera) genome, we used various computational methods, ranging from sequence similarity search to RNA secondary structure prediction, to search for putative snRNA genes (including their promoters) and to examine their pattern of conservation among 11 available insect genomes (A. mellifera, Tribolium castaneum, Bombyx mori, Anopheles gambiae, Aedes aegypti, and six Drosophila species). We identified candidates for all nine spliceosomal snRNA genes in all the analyzed genomes. All the species contain a similar number of snRNA genes, with the exception of A. aegypti, whose genome contains more U1, U2, and U5 genes, and A. mellifera, whose genome contains fewer U2 and U5 genes. We found that snRNA genes are generally more closely related to homologs within the same genus than to those in other genera. Promoter regions for all spliceosomal snRNA genes within each insect species share similar sequence motifs that are likely to correspond to the PSEA (proximal sequence element A), the binding site for snRNA activating protein complex, but these promoter elements vary in sequence among the five insect families surveyed here. In contrast to the other insect species investigated, Dipteran genomes are characterized by a rapid evolution (or loss) of components of the U12 spliceosome and a striking loss of U12-type introns.
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Affiliation(s)
- Stephen M Mount
- Department of Cell Biology and Molecular Genetics, University of Maryland, College Park, Maryland 20742-5815, USA
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Smail SS, Ayesh K, Sierra-Montes JM, Herrera RJ. U6 snRNA variants isolated from the posterior silk gland of the silk moth Bombyx mori. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2006; 36:454-65. [PMID: 16731342 DOI: 10.1016/j.ibmb.2006.03.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/2005] [Revised: 03/09/2006] [Accepted: 03/14/2006] [Indexed: 05/09/2023]
Abstract
Five U6 small nuclear RNA (snRNA) isoforms were detected and characterized from the posterior silk gland (PSG) of the silk moth Bombyx mori (Nistari strain). Using the currently accepted U6 secondary structure model as a basis for comparison, the variants were analyzed for nucleotide differences across the sequence with a focus on known functional domains. Differences were observed primarily in single-stranded areas of which sixty percent were found in the highly conserved U4-U6 binding sites. In the Nistari strain, the U6A variant was found to be approximately four times more abundant as part of high molecular weight spliceosomal complexes when compared with U6A in the total unfractionated PSG cell lysate. Additionally, the European 703 B. mori strain total cell lysate U6 snRNA was analyzed and only the dominant U6A isoform initially identified in Nistari was found. Due to U6's essential role in pre-mRNA processing, variants may modulate assemblage of the catalytic core and in doing so potentially affect the rate of splicing. Phylogenetic analysis of the U6 snRNA sequences indicate an ancient divergence of U6 from the self-splicing group II intron module and a high degree of evolutionary conservation across species possibly due to functional constraints on the gene. Using in silico analysis, 35 full-length U6 variants were observed in the recently released Whole Genome Shotgun (WGS) database of the p50T strain. The consensus sequence of these U6 genes from p50T is identical to U6A identified in the Nistari strain. Furthermore p50T variant 1, which is represented in 14 genes, is equivalent to Nistari U6A.
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Affiliation(s)
- Shamayra S Smail
- Department of Biological Sciences, OE 304, University Park Campus, Florida International University, Miami, FL 33199, USA
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