1
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Shen Z, Naveed M, Bao J. Untacking small RNA profiling and RNA fragment footprinting: Approaches and challenges in library construction. WILEY INTERDISCIPLINARY REVIEWS. RNA 2024; 15:e1852. [PMID: 38715192 DOI: 10.1002/wrna.1852] [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: 02/21/2024] [Revised: 04/09/2024] [Accepted: 04/10/2024] [Indexed: 06/06/2024]
Abstract
Small RNAs (sRNAs) with sizes ranging from 15 to 50 nucleotides (nt) are critical regulators of gene expression control. Prior studies have shown that sRNAs are involved in a broad range of biological processes, such as organ development, tumorigenesis, and epigenomic regulation; however, emerging evidence unveils a hidden layer of diversity and complexity of endogenously encoded sRNAs profile in eukaryotic organisms, including novel types of sRNAs and the previously unknown post-transcriptional RNA modifications. This underscores the importance for accurate, unbiased detection of sRNAs in various cellular contexts. A multitude of high-throughput methods based on next-generation sequencing (NGS) are developed to decipher the sRNA expression and their modifications. Nonetheless, distinct from mRNA sequencing, the data from sRNA sequencing suffer frequent inconsistencies and high variations emanating from the adapter contaminations and RNA modifications, which overall skew the sRNA libraries. Here, we summarize the sRNA-sequencing approaches, and discuss the considerations and challenges for the strategies and methods of sRNA library construction. The pros and cons of sRNA sequencing have significant implications for implementing RNA fragment footprinting approaches, including CLIP-seq and Ribo-seq. We envision that this review can inspire novel improvements in small RNA sequencing and RNA fragment footprinting in future. This article is categorized under: RNA Evolution and Genomics > Computational Analyses of RNA RNA Processing > Processing of Small RNAs Regulatory RNAs/RNAi/Riboswitches > Biogenesis of Effector Small RNAs.
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Affiliation(s)
- Zhaokang Shen
- Department of Obstetrics and Gynecology, Center for Reproduction and Genetics, The First Affiliated Hospital of USTC, Center for Advanced Interdisciplinary Science and Biomedicine of IHM, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, Anhui, China
- Hefei National Laboratory for Physical Sciences at Microscale, Biomedical Sciences and Health Laboratory of Anhui Province, University of Science and Technology of China (USTC), Hefei, Anhui, China
| | - Muhammad Naveed
- Hefei National Laboratory for Physical Sciences at Microscale, Biomedical Sciences and Health Laboratory of Anhui Province, University of Science and Technology of China (USTC), Hefei, Anhui, China
- Department of Obstetrics and Gynecology, Center for Reproduction and Genetics, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, Anhui, China
| | - Jianqiang Bao
- Department of Obstetrics and Gynecology, Center for Reproduction and Genetics, The First Affiliated Hospital of USTC, Center for Advanced Interdisciplinary Science and Biomedicine of IHM, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, Anhui, China
- Hefei National Laboratory for Physical Sciences at Microscale, Biomedical Sciences and Health Laboratory of Anhui Province, University of Science and Technology of China (USTC), Hefei, Anhui, China
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2
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Liu S, Huang J, Zhou J, Chen S, Zheng W, Liu C, Lin Q, Zhang P, Wu D, He S, Ye J, Liu S, Zhou K, Li B, Qu L, Yang J. NAP-seq reveals multiple classes of structured noncoding RNAs with regulatory functions. Nat Commun 2024; 15:2425. [PMID: 38499544 PMCID: PMC10948791 DOI: 10.1038/s41467-024-46596-y] [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: 07/11/2022] [Accepted: 03/04/2024] [Indexed: 03/20/2024] Open
Abstract
Up to 80% of the human genome produces "dark matter" RNAs, most of which are noncapped RNAs (napRNAs) that frequently act as noncoding RNAs (ncRNAs) to modulate gene expression. Here, by developing a method, NAP-seq, to globally profile the full-length sequences of napRNAs with various terminal modifications at single-nucleotide resolution, we reveal diverse classes of structured ncRNAs. We discover stably expressed linear intron RNAs (sliRNAs), a class of snoRNA-intron RNAs (snotrons), a class of RNAs embedded in miRNA spacers (misRNAs) and thousands of previously uncharacterized structured napRNAs in humans and mice. These napRNAs undergo dynamic changes in response to various stimuli and differentiation stages. Importantly, we show that a structured napRNA regulates myoblast differentiation and a napRNA DINAP interacts with dyskerin pseudouridine synthase 1 (DKC1) to promote cell proliferation by maintaining DKC1 protein stability. Our approach establishes a paradigm for discovering various classes of ncRNAs with regulatory functions.
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Affiliation(s)
- Shurong Liu
- MOE Key Laboratory of Gene Function and Regulation, State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, 510275, Guangdong, China
| | - Junhong Huang
- MOE Key Laboratory of Gene Function and Regulation, State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, 510275, Guangdong, China
- The Fifth Affiliated Hospital, Sun Yat-sen University, Zhuhai, 519082, Guangdong, 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, 510275, Guangdong, China
| | - Siyan Chen
- MOE Key Laboratory of Gene Function and Regulation, State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, 510275, Guangdong, China
- The Fifth Affiliated Hospital, Sun Yat-sen University, Zhuhai, 519082, Guangdong, 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, 510275, Guangdong, 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, 510275, Guangdong, 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, 510275, Guangdong, 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, 510275, Guangdong, 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, 510275, Guangdong, China
- The Fifth Affiliated Hospital, Sun Yat-sen University, Zhuhai, 519082, Guangdong, China
| | - Simeng He
- The Fifth Affiliated Hospital, Sun Yat-sen University, Zhuhai, 519082, Guangdong, 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, 510275, Guangdong, China
| | - Shun Liu
- Department of Chemistry, The University of Chicago, Chicago, IL, 60637, USA
| | - Keren Zhou
- Department of Systems Biology, Beckman Research Institute of City of Hope, Monrovia, CA, 91016, USA
| | - Bin Li
- MOE Key Laboratory of Gene Function and Regulation, State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, 510275, Guangdong, China.
| | - Lianghu Qu
- MOE Key Laboratory of Gene Function and Regulation, State Key Laboratory of Biocontrol, School of Life Sciences, Sun Yat-sen University, Guangzhou, 510275, Guangdong, 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, 510275, Guangdong, China.
- The Fifth Affiliated Hospital, Sun Yat-sen University, Zhuhai, 519082, Guangdong, China.
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3
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Tosar JP, Castellano M, Costa B, Cayota A. Small RNA structural biochemistry in a post-sequencing era. Nat Protoc 2024; 19:595-602. [PMID: 38057624 DOI: 10.1038/s41596-023-00936-2] [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: 02/23/2023] [Accepted: 08/25/2023] [Indexed: 12/08/2023]
Abstract
High-throughput sequencing has had an enormous impact on small RNA research during the past decade. However, sequencing only offers a one-dimensional view of the transcriptome and is often highly biased. Additionally, the 'sequence, map and annotate' approach, used widely in small RNA research, can lead to flawed interpretations of the data, lacking biological plausibility, due in part to database issues. Even in the absence of technical biases, the loss of three-dimensional information is a major limitation to understanding RNA stability, turnover and function. For example, noncoding RNA-derived fragments seem to exist mainly as dimers, tetramers or as nicked forms of their parental RNAs, contrary to widespread assumptions. In this perspective, we will discuss main sources of bias during small RNA-sequencing, present several useful bias-reducing strategies and provide guidance on the interpretation of small RNA-sequencing results, with emphasis on RNA fragmentomics. As sequencing offers a one-dimensional projection of a four-dimensional reality, prior structure-level knowledge is often needed to make sense of the data. Consequently, while less-biased sequencing methods are welcomed, integration of orthologous experimental techniques is also strongly recommended.
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Affiliation(s)
- Juan Pablo Tosar
- Functional Genomics Laboratory, Institut Pasteur de Montevideo, Montevideo, Uruguay.
- Analytical Biochemistry Unit, Center for Nuclear Research, School of Science, Universidad de la República, Montevideo, Uruguay.
| | - Mauricio Castellano
- Functional Genomics Laboratory, Institut Pasteur de Montevideo, Montevideo, Uruguay
- Biochemistry Department, School of Science, Universidad de la República, Montevideo, Uruguay
| | - Bruno Costa
- Functional Genomics Laboratory, Institut Pasteur de Montevideo, Montevideo, Uruguay
- Analytical Biochemistry Unit, Center for Nuclear Research, School of Science, Universidad de la República, Montevideo, Uruguay
| | - Alfonso Cayota
- Functional Genomics Laboratory, Institut Pasteur de Montevideo, Montevideo, Uruguay
- Hospital de Clínicas, Universidad de la República, Montevideo, Uruguay
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4
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Anderson R, Das MR, Chang Y, Farenhem K, Schmitz CO, Jain A. CAG repeat expansions create splicing acceptor sites and produce aberrant repeat-containing RNAs. Mol Cell 2024; 84:702-714.e10. [PMID: 38295802 PMCID: PMC10923110 DOI: 10.1016/j.molcel.2024.01.006] [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: 08/20/2023] [Revised: 11/07/2023] [Accepted: 01/08/2024] [Indexed: 02/04/2024]
Abstract
Expansions of CAG trinucleotide repeats cause several rare neurodegenerative diseases. The disease-causing repeats are translated in multiple reading frames and without an identifiable initiation codon. The molecular mechanism of this repeat-associated non-AUG (RAN) translation is not known. We find that expanded CAG repeats create new splice acceptor sites. Splicing of proximal donors to the repeats produces unexpected repeat-containing transcripts. Upon splicing, depending on the sequences surrounding the donor, CAG repeats may become embedded in AUG-initiated open reading frames. Canonical AUG-initiated translation of these aberrant RNAs may account for proteins that have been attributed to RAN translation. Disruption of the relevant splice donors or the in-frame AUG initiation codons is sufficient to abrogate RAN translation. Our findings provide a molecular explanation for the abnormal translation products observed in CAG trinucleotide repeat expansion disorders and add to the repertoire of mechanisms by which repeat expansion mutations disrupt cellular functions.
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Affiliation(s)
- Rachel Anderson
- Whitehead Institute for Biomedical Research, 455 Main Street, Cambridge, MA 02142, USA; Department of Biology, Massachusetts Institute of Technology, 31 Ames Street, Cambridge, MA 02139, USA
| | - Michael R Das
- Whitehead Institute for Biomedical Research, 455 Main Street, Cambridge, MA 02142, USA; Department of Biology, Massachusetts Institute of Technology, 31 Ames Street, Cambridge, MA 02139, USA
| | - Yeonji Chang
- Whitehead Institute for Biomedical Research, 455 Main Street, Cambridge, MA 02142, USA
| | - Kelsey Farenhem
- Whitehead Institute for Biomedical Research, 455 Main Street, Cambridge, MA 02142, USA; Department of Biology, Massachusetts Institute of Technology, 31 Ames Street, Cambridge, MA 02139, USA
| | - Cameron O Schmitz
- Whitehead Institute for Biomedical Research, 455 Main Street, Cambridge, MA 02142, USA; Department of Biology, Massachusetts Institute of Technology, 31 Ames Street, Cambridge, MA 02139, USA
| | - Ankur Jain
- Whitehead Institute for Biomedical Research, 455 Main Street, Cambridge, MA 02142, USA; Department of Biology, Massachusetts Institute of Technology, 31 Ames Street, Cambridge, MA 02139, USA.
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5
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Fafard-Couture É, Labialle S, Scott MS. The regulatory roles of small nucleolar RNAs within their host locus. RNA Biol 2024; 21:1-11. [PMID: 38626213 PMCID: PMC11028025 DOI: 10.1080/15476286.2024.2342685] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/08/2024] [Indexed: 04/18/2024] Open
Abstract
Small nucleolar RNAs (snoRNAs) are a class of conserved noncoding RNAs forming complexes with proteins to catalyse site-specific modifications on ribosomal RNA. Besides this canonical role, several snoRNAs are now known to regulate diverse levels of gene expression. While these functions are carried out in trans by mature snoRNAs, evidence has also been emerging of regulatory roles of snoRNAs in cis, either within their genomic locus or as longer transcription intermediates during their maturation. Herein, we review recent findings that snoRNAs can interact in cis with their intron to regulate the expression of their host gene. We also explore the ever-growing diversity of longer host-derived snoRNA extensions and their functional impact across the transcriptome. Finally, we discuss the role of snoRNA duplications into forging these new layers of snoRNA-mediated regulation, as well as their involvement in the genomic imprinting of their host locus.
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Affiliation(s)
- Étienne Fafard-Couture
- Département de biochimie et de génomique fonctionnelle, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, Québec, Canada
| | | | - Michelle S Scott
- Département de biochimie et de génomique fonctionnelle, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, Québec, Canada
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6
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Anderson R, Das M, Chang Y, Farenhem K, Jain A. CAG repeat expansions create splicing acceptor sites and produce aberrant repeat-containing RNAs. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.10.16.562581. [PMID: 37904984 PMCID: PMC10614865 DOI: 10.1101/2023.10.16.562581] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/02/2023]
Abstract
Expansions of CAG trinucleotide repeats cause several rare neurodegenerative diseases. The disease-causing repeats are translated in multiple reading frames, without an identifiable initiation codon. The molecular mechanism of this repeat-associated non-AUG (RAN) translation is not known. We find that expanded CAG repeats create new splice acceptor sites. Splicing of proximal donors to the repeats produces unexpected repeat-containing transcripts. Upon splicing, depending on the sequences surrounding the donor, CAG repeats may become embedded in AUG-initiated open reading frames. Canonical AUG-initiated translation of these aberrant RNAs accounts for proteins that are attributed to RAN translation. Disruption of the relevant splice donors or the in-frame AUG initiation codons is sufficient to abrogate RAN translation. Our findings provide a molecular explanation for the abnormal translation products observed in CAG trinucleotide repeat expansion disorders and add to the repertoire of mechanisms by which repeat expansion mutations disrupt cellular functions.
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Affiliation(s)
- Rachel Anderson
- Whitehead Institute for Biomedical Research, 455 Main Street, Cambridge, MA 02142, USA
- Department of Biology, Massachusetts Institute of Technology, 31 Ames Street, Cambridge, MA 02139, USA
| | - Michael Das
- Whitehead Institute for Biomedical Research, 455 Main Street, Cambridge, MA 02142, USA
- Department of Biology, Massachusetts Institute of Technology, 31 Ames Street, Cambridge, MA 02139, USA
| | - Yeonji Chang
- Whitehead Institute for Biomedical Research, 455 Main Street, Cambridge, MA 02142, USA
| | - Kelsey Farenhem
- Whitehead Institute for Biomedical Research, 455 Main Street, Cambridge, MA 02142, USA
- Department of Biology, Massachusetts Institute of Technology, 31 Ames Street, Cambridge, MA 02139, USA
| | - Ankur Jain
- Whitehead Institute for Biomedical Research, 455 Main Street, Cambridge, MA 02142, USA
- Department of Biology, Massachusetts Institute of Technology, 31 Ames Street, Cambridge, MA 02139, USA
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7
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Bergeron D, Faucher-Giguère L, Emmerichs AK, Choquet K, Song KS, Deschamps-Francoeur G, Fafard-Couture É, Rivera A, Couture S, Churchman LS, Heyd F, Abou Elela S, Scott MS. Intronic small nucleolar RNAs regulate host gene splicing through base pairing with their adjacent intronic sequences. Genome Biol 2023; 24:160. [PMID: 37415181 PMCID: PMC10324135 DOI: 10.1186/s13059-023-03002-y] [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: 10/25/2022] [Accepted: 06/29/2023] [Indexed: 07/08/2023] Open
Abstract
BACKGROUND Small nucleolar RNAs (snoRNAs) are abundant noncoding RNAs best known for their involvement in ribosomal RNA maturation. In mammals, most expressed snoRNAs are embedded in introns of longer genes and produced through transcription and splicing of their host. Intronic snoRNAs were long viewed as inert passengers with little effect on host expression. However, a recent study reported a snoRNA influencing the splicing and ultimate output of its host gene. Overall, the general contribution of intronic snoRNAs to host expression remains unclear. RESULTS Computational analysis of large-scale human RNA-RNA interaction datasets indicates that 30% of detected snoRNAs interact with their host transcripts. Many snoRNA-host duplexes are located near alternatively spliced exons and display high sequence conservation suggesting a possible role in splicing regulation. The study of the model SNORD2-EIF4A2 duplex indicates that the snoRNA interaction with the host intronic sequence conceals the branch point leading to decreased inclusion of the adjacent alternative exon. Extended SNORD2 sequence containing the interacting intronic region accumulates in sequencing datasets in a cell-type-specific manner. Antisense oligonucleotides and mutations that disrupt the formation of the snoRNA-intron structure promote the splicing of the alternative exon, shifting the EIF4A2 transcript ratio away from nonsense-mediated decay. CONCLUSIONS Many snoRNAs form RNA duplexes near alternative exons of their host transcripts, placing them in optimal positions to control host output as shown for the SNORD2-EIF4A2 model system. Overall, our study supports a more widespread role for intronic snoRNAs in the regulation of their host transcript maturation.
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Affiliation(s)
- Danny Bergeron
- Département de Biochimie Et Génomique Fonctionnelle, Faculté de Médecine Et Des Sciences de La Santé, Université de Sherbrooke, Sherbrooke, Québec, J1E 4K8, Canada
| | - Laurence Faucher-Giguère
- Département de Microbiologie Et d'infectiologie, Faculté de Médecine Et Des Sciences de La Santé, Université de Sherbrooke, Sherbrooke, Québec, J1E 4K8, Canada
| | - Ann-Kathrin Emmerichs
- Institute of Chemistry and Biochemistry, Freie Universität Berlin, Laboratory of RNA Biochemistry, Takustrasse 6, 14195, Berlin, Germany
| | - Karine Choquet
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, MA, 02115, USA
| | - Kristina Sungeun Song
- Département de Biochimie Et Génomique Fonctionnelle, Faculté de Médecine Et Des Sciences de La Santé, Université de Sherbrooke, Sherbrooke, Québec, J1E 4K8, Canada
| | - Gabrielle Deschamps-Francoeur
- Département de Biochimie Et Génomique Fonctionnelle, Faculté de Médecine Et Des Sciences de La Santé, Université de Sherbrooke, Sherbrooke, Québec, J1E 4K8, Canada
| | - Étienne Fafard-Couture
- Département de Biochimie Et Génomique Fonctionnelle, Faculté de Médecine Et Des Sciences de La Santé, Université de Sherbrooke, Sherbrooke, Québec, J1E 4K8, Canada
| | - Andrea Rivera
- Département de Microbiologie Et d'infectiologie, Faculté de Médecine Et Des Sciences de La Santé, Université de Sherbrooke, Sherbrooke, Québec, J1E 4K8, Canada
| | - Sonia Couture
- Département de Microbiologie Et d'infectiologie, Faculté de Médecine Et Des Sciences de La Santé, Université de Sherbrooke, Sherbrooke, Québec, J1E 4K8, Canada
| | - L Stirling Churchman
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, MA, 02115, USA
| | - Florian Heyd
- Institute of Chemistry and Biochemistry, Freie Universität Berlin, Laboratory of RNA Biochemistry, Takustrasse 6, 14195, Berlin, Germany
| | - Sherif Abou Elela
- Département de Microbiologie Et d'infectiologie, Faculté de Médecine Et Des Sciences de La Santé, Université de Sherbrooke, Sherbrooke, Québec, J1E 4K8, Canada
| | - Michelle S Scott
- Département de Biochimie Et Génomique Fonctionnelle, Faculté de Médecine Et Des Sciences de La Santé, Université de Sherbrooke, Sherbrooke, Québec, J1E 4K8, Canada.
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8
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Wylie D, Wang X, Yao J, Xu H, Ferrick-Kiddie EA, Iwase T, Krishnamurthy S, Ueno NT, Lambowitz AM. Inflammatory breast cancer biomarker identification by simultaneous TGIRT-seq profiling of coding and non-coding RNAs in tumors and blood. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2023:2023.05.26.23290469. [PMID: 37398275 PMCID: PMC10312853 DOI: 10.1101/2023.05.26.23290469] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/04/2023]
Abstract
Inflammatory breast cancer (IBC) is the most aggressive and lethal breast cancer subtype, but lags in biomarker identification. Here, we used an improved Thermostable Group II Intron Reverse Transcriptase RNA sequencing (TGIRT-seq) method to simultaneously profile coding and non-coding RNAs from tumors, PBMCs, and plasma of IBC and non-IBC patients and healthy donors. Besides RNAs from known IBC-relevant genes, we identified hundreds of other overexpressed coding and non-coding RNAs (p≤0.001) in IBC tumors and PBMCs, including higher proportions with elevated intron-exon depth ratios (IDRs), likely reflecting enhanced transcription resulting in accumulation of intronic RNAs. As a consequence, differentially represented protein-coding gene RNAs in IBC plasma were largely intron RNA fragments, whereas those in healthy donor and non-IBC plasma were largely fragmented mRNAs. Potential IBC biomarkers in plasma included T-cell receptor pre-mRNA fragments traced to IBC tumors and PBMCs; intron RNA fragments correlated with high IDR genes; and LINE-1 and other retroelement RNAs that we found globally up-regulated in IBC and preferentially enriched in plasma. Our findings provide new insights into IBC and demonstrate advantages of broadly analyzing transcriptomes for biomarker identification. The RNA-seq and data analysis methods developed for this study may be broadly applicable to other diseases.
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Affiliation(s)
- Dennis Wylie
- Departments of Molecular Biosciences and Oncology, University of Texas at Austin, Austin, TX 78712
| | - Xiaoping Wang
- Department of Breast Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030
- Morgan Welch Inflammatory Breast Cancer Research Program and Clinic, The University of Texas MD Anderson Cancer Center, Houston, TX 77030
| | - Jun Yao
- Departments of Molecular Biosciences and Oncology, University of Texas at Austin, Austin, TX 78712
| | - Hengyi Xu
- Departments of Molecular Biosciences and Oncology, University of Texas at Austin, Austin, TX 78712
| | | | - Toshiaki Iwase
- Department of Breast Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030
- Morgan Welch Inflammatory Breast Cancer Research Program and Clinic, The University of Texas MD Anderson Cancer Center, Houston, TX 77030
- University of Hawai'i Cancer Center, Honolulu, HI 96813
| | - Savitri Krishnamurthy
- Morgan Welch Inflammatory Breast Cancer Research Program and Clinic, The University of Texas MD Anderson Cancer Center, Houston, TX 77030
- Department of Hematopathology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030
| | - Naoto T Ueno
- Department of Breast Medical Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030
- Morgan Welch Inflammatory Breast Cancer Research Program and Clinic, The University of Texas MD Anderson Cancer Center, Houston, TX 77030
- University of Hawai'i Cancer Center, Honolulu, HI 96813
| | - Alan M Lambowitz
- Departments of Molecular Biosciences and Oncology, University of Texas at Austin, Austin, TX 78712
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9
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Huber LB, Betz K, Marx A. Reverse Transcriptases: From Discovery and Applications to Xenobiology. Chembiochem 2023; 24:e202200521. [PMID: 36354312 DOI: 10.1002/cbic.202200521] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2022] [Revised: 11/09/2022] [Indexed: 11/12/2022]
Abstract
Reverse transcriptases are DNA polymerases that can use RNA as a template for DNA synthesis. They thus catalyze the reverse of transcription. Although discovered in 1970, reverse transcriptases are still of great interest and are constantly being further developed for numerous modern research approaches. They are frequently used in biotechnological and molecular diagnostic applications. In this review, we describe the discovery of these fascinating enzymes and summarize research results and applications ranging from molecular cloning, direct virus detection, and modern sequencing methods to xenobiology.
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Affiliation(s)
- Luisa B Huber
- Department of Chemistry, Konstanz Research School Chemical Biology, University of Konstanz, Universitätsstrasse 10, 78464, Konstanz, Germany
| | - Karin Betz
- Department of Chemistry, Konstanz Research School Chemical Biology, University of Konstanz, Universitätsstrasse 10, 78464, Konstanz, Germany
| | - Andreas Marx
- Department of Chemistry, Konstanz Research School Chemical Biology, University of Konstanz, Universitätsstrasse 10, 78464, Konstanz, Germany
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10
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Ng KY, Battersby BJ. Sucrose Gradient Analysis of Human Mitochondrial Ribosomes and RNA. Methods Mol Biol 2023; 2661:101-117. [PMID: 37166634 DOI: 10.1007/978-1-0716-3171-3_7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Faithful expression of the mitochondrial genome is required for the synthesis of the oxidative phosphorylation complexes and cell fitness. In humans, mitochondrial DNA (mtDNA) encodes 13 essential subunits of four oxidative phosphorylation complexes along with tRNAs and rRNAs needed for the translation of these proteins. Protein synthesis occurs on unique ribosomes within the organelle. Over the last decade, the revolution in genetic diagnostics has identified disruptions to the faithful synthesis of these 13 mitochondrial proteins as the largest group of inherited human mitochondrial pathologies. All of the molecular steps required for mitochondrial protein synthesis can be affected, from the genome to protein, including cotranslational quality control. Here, we describe methodologies for the biochemical separation of mitochondrial ribosomes from cultured human cells for RNA and protein analysis. Our method has been optimized to facilitate analysis for low-level sample material and thus does not require prior organelle enrichment.
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Affiliation(s)
- Kah Ying Ng
- Institute of Biotechnology, Helsinki Institute of Life Science, University of Helsinki, Helsinki, Finland
| | - Brendan J Battersby
- Institute of Biotechnology, Helsinki Institute of Life Science, University of Helsinki, Helsinki, Finland.
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11
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Altered tRNA processing is linked to a distinct and unusual La protein in Tetrahymena thermophila. Nat Commun 2022; 13:7332. [PMID: 36443289 PMCID: PMC9705548 DOI: 10.1038/s41467-022-34796-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2022] [Accepted: 11/07/2022] [Indexed: 11/29/2022] Open
Abstract
Nascent pre-tRNAs are transcribed by RNA polymerase III and immediately bound by La proteins on the UUU-3'OH sequence, using a tandem arrangement of the La motif and an adjacent RNA recognition motif-1 (RRM1), resulting in protection from 3'-exonucleases and promotion of pre-tRNA folding. The Tetrahymena thermophila protein Mlp1 has been previously classified as a genuine La protein, despite the predicted absence of the RRM1. We find that Mlp1 functions as a La protein through binding of pre-tRNAs, and affects pre-tRNA processing in Tetrahymena thermophila and when expressed in fission yeast. However, unlike in other examined eukaryotes, depletion of Mlp1 results in 3'-trailer stabilization. The 3'-trailers in Tetrahymena thermophila are uniquely short relative to other examined eukaryotes, and 5'-leaders have evolved to disfavour pre-tRNA leader/trailer pairing. Our data indicate that this variant Mlp1 architecture is linked to an altered, novel mechanism of tRNA processing in Tetrahymena thermophila.
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Ng KY, Lutfullahoglu Bal G, Richter U, Safronov O, Paulin L, Dunn CD, Paavilainen VO, Richer J, Newman WG, Taylor RW, Battersby BJ. Nonstop mRNAs generate a ground state of mitochondrial gene expression noise. SCIENCE ADVANCES 2022; 8:eabq5234. [PMID: 36399564 PMCID: PMC9674279 DOI: 10.1126/sciadv.abq5234] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/2022] [Accepted: 10/22/2022] [Indexed: 05/29/2023]
Abstract
A stop codon within the mRNA facilitates coordinated termination of protein synthesis, releasing the nascent polypeptide from the ribosome. This essential step in gene expression is impeded with transcripts lacking a stop codon, generating nonstop ribosome complexes. Here, we use deep sequencing to investigate sources of nonstop mRNAs generated from the human mitochondrial genome. We identify diverse types of nonstop mRNAs on mitochondrial ribosomes that are resistant to translation termination by canonical release factors. Failure to resolve these aberrations by the mitochondrial release factor in rescue (MTRFR) imparts a negative regulatory effect on protein synthesis that is associated with human disease. Our findings reveal a source of underlying noise in mitochondrial gene expression and the importance of responsive ribosome quality control mechanisms for cell fitness and human health.
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Affiliation(s)
- Kah Ying Ng
- Institute of Biotechnology, Helsinki Institute of Life Science, University of Helsinki, Helsinki, Finland
| | - Guleycan Lutfullahoglu Bal
- Institute of Biotechnology, Helsinki Institute of Life Science, University of Helsinki, Helsinki, Finland
| | - Uwe Richter
- Institute of Biotechnology, Helsinki Institute of Life Science, University of Helsinki, Helsinki, Finland
- Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland
- Wellcome Centre for Mitochondrial Research, Biosciences Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, UK
| | - Omid Safronov
- Institute of Biotechnology, Helsinki Institute of Life Science, University of Helsinki, Helsinki, Finland
- Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland
| | - Lars Paulin
- Institute of Biotechnology, Helsinki Institute of Life Science, University of Helsinki, Helsinki, Finland
- DNA Sequencing and Genomics Laboratory, University of Helsinki, Helsinki, Finland
| | - Cory D. Dunn
- Institute of Biotechnology, Helsinki Institute of Life Science, University of Helsinki, Helsinki, Finland
| | - Ville O. Paavilainen
- Institute of Biotechnology, Helsinki Institute of Life Science, University of Helsinki, Helsinki, Finland
| | - Julie Richer
- Department of Medical Genetics, Children’s Hospital of Eastern Ontario, Ottawa, ON, Canada
| | - William G. Newman
- Manchester Centre for Genomic Medicine, St. Mary’s Hospital, Manchester University NHS Foundation Trust, Manchester, UK
- Division of Evolution, Infection and Genomics, School of Biological Sciences, University of Manchester, Manchester, UK
| | - Robert W. Taylor
- Wellcome Centre for Mitochondrial Research, Translational and Clinical Research Institute, Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, UK
- NHS Highly Specialised Service for Rare Mitochondrial Disorders, Newcastle upon Tyne Hospitals NHS Foundation Trust, Newcastle upon Tyne, UK
| | - Brendan J. Battersby
- Institute of Biotechnology, Helsinki Institute of Life Science, University of Helsinki, Helsinki, Finland
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Mai D, Ye Y, Zhuang L, Zheng J, Lin D. Detection of piRNA-54265 in human serum: evidence and significance. Cancer Commun (Lond) 2022; 43:276-279. [PMID: 36336968 PMCID: PMC9926952 DOI: 10.1002/cac2.12381] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2022] [Revised: 09/09/2022] [Accepted: 10/20/2022] [Indexed: 11/09/2022] Open
Affiliation(s)
- Dongmei Mai
- Department of Experimental ResearchSun Yat‐sen University Cancer CenterState Key Laboratory of Oncology in South China and Collaborative Innovation Center for Cancer MedicineGuangzhouGuangdong510060P. R. China
| | - Ying Ye
- Department of Experimental ResearchSun Yat‐sen University Cancer CenterState Key Laboratory of Oncology in South China and Collaborative Innovation Center for Cancer MedicineGuangzhouGuangdong510060P. R. China
| | - Lisha Zhuang
- Department of Experimental ResearchSun Yat‐sen University Cancer CenterState Key Laboratory of Oncology in South China and Collaborative Innovation Center for Cancer MedicineGuangzhouGuangdong510060P. R. China
| | - Jian Zheng
- Department of Experimental ResearchSun Yat‐sen University Cancer CenterState Key Laboratory of Oncology in South China and Collaborative Innovation Center for Cancer MedicineGuangzhouGuangdong510060P. R. China
| | - Dongxin Lin
- Department of Experimental ResearchSun Yat‐sen University Cancer CenterState Key Laboratory of Oncology in South China and Collaborative Innovation Center for Cancer MedicineGuangzhouGuangdong510060P. R. China,Department of Etiology and CarcinogenesisNational Cancer Center/Cancer HospitalChinese Academy of Medical Sciences and Peking Union Medical CollegeBeijing100021P. R. China
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14
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Park SK, Mohr G, Yao J, Russell R, Lambowitz AM. Group II intron-like reverse transcriptases function in double-strand break repair. Cell 2022; 185:3671-3688.e23. [PMID: 36113466 PMCID: PMC9530004 DOI: 10.1016/j.cell.2022.08.014] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2022] [Revised: 06/16/2022] [Accepted: 08/14/2022] [Indexed: 01/26/2023]
Abstract
Bacteria encode reverse transcriptases (RTs) of unknown function that are closely related to group II intron-encoded RTs. We found that a Pseudomonas aeruginosa group II intron-like RT (G2L4 RT) with YIDD instead of YADD at its active site functions in DNA repair in its native host and when expressed in Escherichia coli. G2L4 RT has biochemical activities strikingly similar to those of human DNA repair polymerase θ and uses them for translesion DNA synthesis and double-strand break repair (DSBR) via microhomology-mediated end-joining (MMEJ). We also found that a group II intron RT can function similarly in DNA repair, with reciprocal active-site substitutions showing isoleucine favors MMEJ and alanine favors primer extension in both enzymes. These DNA repair functions utilize conserved structural features of non-LTR-retroelement RTs, including human LINE-1 and other eukaryotic non-LTR-retrotransposon RTs, suggesting such enzymes may have inherent ability to function in DSBR in a wide range of organisms.
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Affiliation(s)
- Seung Kuk Park
- Departments of Molecular Biosciences and Oncology, University of Texas at Austin, Austin, TX 78712, USA
| | - Georg Mohr
- Departments of Molecular Biosciences and Oncology, University of Texas at Austin, Austin, TX 78712, USA
| | - Jun Yao
- Departments of Molecular Biosciences and Oncology, University of Texas at Austin, Austin, TX 78712, USA
| | - Rick Russell
- Departments of Molecular Biosciences and Oncology, University of Texas at Austin, Austin, TX 78712, USA
| | - Alan M Lambowitz
- Departments of Molecular Biosciences and Oncology, University of Texas at Austin, Austin, TX 78712, USA.
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15
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Bergeron D, Paraqindes H, Fafard-Couture É, Deschamps-Francoeur G, Faucher-Giguère L, Bouchard-Bourelle P, Abou Elela S, Catez F, Marcel V, Scott M. snoDB 2.0: an enhanced interactive database, specializing in human snoRNAs. Nucleic Acids Res 2022; 51:D291-D296. [PMID: 36165892 PMCID: PMC9825428 DOI: 10.1093/nar/gkac835] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2022] [Revised: 09/06/2022] [Accepted: 09/16/2022] [Indexed: 01/29/2023] Open
Abstract
snoDB is an interactive database of human small nucleolar RNAs (snoRNAs) that includes up-to-date information on snoRNA features, genomic location, conservation, host gene, snoRNA-RNA targets and snoRNA abundance and provides links to other resources. In the second edition of this database (snoDB 2.0), we added an entirely new section on ribosomal RNA (rRNA) chemical modifications guided by snoRNAs with easy navigation between the different rRNA versions used in the literature and experimentally measured levels of modification. We also included new layers of information, including snoRNA motifs, secondary structure prediction, snoRNA-protein interactions, copy annotations and low structure bias expression data in a wide panel of tissues and cell lines to bolster functional probing of snoRNA biology. Version 2.0 features updated identifiers, more links to external resources and duplicate entry resolution. As a result, snoDB 2.0, which is freely available at https://bioinfo-scottgroup.med.usherbrooke.ca/snoDB/, represents a one-stop shop for snoRNA features, rRNA modification targets, functional impact and potential regulators.
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Affiliation(s)
- Danny Bergeron
- Département de biochimie et génomique fonctionnelle, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, Québec J1E 4K8, Canada
| | - Hermes Paraqindes
- Inserm U1052, CNRS UMR5286 Centre de Recherche en Cancérologie de Lyon, F-69000 Lyon, France,Centre Léon Bérard, F-69008 Lyon, France,Université de Lyon 1, F-69000 Lyon, France
| | - Étienne Fafard-Couture
- Département de biochimie et génomique fonctionnelle, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, Québec J1E 4K8, Canada
| | - Gabrielle Deschamps-Francoeur
- Département de biochimie et génomique fonctionnelle, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, Québec J1E 4K8, Canada
| | - Laurence Faucher-Giguère
- Département de microbiologie et d’infectiologie, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, Québec J1E 4K8, Canada
| | - Philia Bouchard-Bourelle
- Département de biochimie et génomique fonctionnelle, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, Québec J1E 4K8, Canada
| | - Sherif Abou Elela
- Département de microbiologie et d’infectiologie, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, Québec J1E 4K8, Canada
| | - Frédéric Catez
- Inserm U1052, CNRS UMR5286 Centre de Recherche en Cancérologie de Lyon, F-69000 Lyon, France,Centre Léon Bérard, F-69008 Lyon, France,Université de Lyon 1, F-69000 Lyon, France,Institut Convergence PLAsCAN, F-69373 Lyon, France
| | - Virginie Marcel
- Inserm U1052, CNRS UMR5286 Centre de Recherche en Cancérologie de Lyon, F-69000 Lyon, France,Centre Léon Bérard, F-69008 Lyon, France,Université de Lyon 1, F-69000 Lyon, France,Institut Convergence PLAsCAN, F-69373 Lyon, France
| | - Michelle S Scott
- To whom correspondence should be addressed. Tel: +1 819 821 8000 (Ext 72123);
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16
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Faucher-Giguère L, Roy A, Deschamps-Francoeur G, Couture S, Nottingham RM, Lambowitz AM, Scott MS, Abou Elela S. High-grade ovarian cancer associated H/ACA snoRNAs promote cancer cell proliferation and survival. NAR Cancer 2022; 4:zcab050. [PMID: 35047824 PMCID: PMC8759569 DOI: 10.1093/narcan/zcab050] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Revised: 12/08/2021] [Accepted: 12/13/2021] [Indexed: 01/10/2023] Open
Abstract
Small nucleolar RNAs (snoRNAs) are an omnipresent class of non-coding RNAs involved in the modification and processing of ribosomal RNA (rRNA). As snoRNAs are required for ribosome production, the increase of which is a hallmark of cancer development, their expression would be expected to increase in proliferating cancer cells. However, assessing the nature and extent of snoRNAs' contribution to cancer biology has been largely limited by difficulties in detecting highly structured RNA. In this study, we used a dedicated midsize non-coding RNA (mncRNA) sensitive sequencing technique to accurately survey the snoRNA abundance in independently verified high-grade serous ovarian carcinoma (HGSC) and serous borderline tumour (SBT) tissues. The results identified SNORA81, SNORA19 and SNORA56 as an H/ACA snoRNA signature capable of discriminating between independent sets of HGSC, SBT and normal tissues. The expression of the signature SNORA81 correlates with the level of ribosomal RNA (rRNA) modification and its knockdown inhibits 28S rRNA pseudouridylation and accumulation leading to reduced cell proliferation and migration. Together our data indicate that specific subsets of H/ACA snoRNAs may promote tumour aggressiveness by inducing rRNA modification and synthesis.
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Affiliation(s)
| | | | | | | | | | | | | | - Sherif Abou Elela
- To whom correspondence should be addressed. Tel: +1 819 821 8000 (Ext 75275);
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17
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Potemkin N, Cawood SMF, Treece J, Guévremont D, Rand CJ, McLean C, Stanton JAL, Williams JM. A method for simultaneous detection of small and long RNA biotypes by ribodepleted RNA-Seq. Sci Rep 2022; 12:621. [PMID: 35022475 PMCID: PMC8755727 DOI: 10.1038/s41598-021-04209-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Accepted: 11/24/2021] [Indexed: 11/09/2022] Open
Abstract
RNA sequencing offers unprecedented access to the transcriptome. Key to this is the identification and quantification of many different species of RNA from the same sample at the same time. In this study we describe a novel protocol for simultaneous detection of coding and non-coding transcripts using modifications to the Ion Total RNA-Seq kit v2 protocol, with integration of QIASeq FastSelect rRNA removal kit. We report highly consistent sequencing libraries can be produced from both frozen high integrity mouse hippocampal tissue and the more challenging post-mortem human tissue. Removal of rRNA using FastSelect was extremely efficient, resulting in less than 1.5% rRNA content in the final library. We identified > 30,000 unique transcripts from all samples, including protein-coding genes and many species of non-coding RNA, in biologically-relevant proportions. Furthermore, the normalized sequencing read count for select genes significantly negatively correlated with Ct values from qRT-PCR analysis from the same samples. These results indicate that this protocol accurately and consistently identifies and quantifies a wide variety of transcripts simultaneously. The highly efficient rRNA depletion, coupled with minimized sample handling and without complicated and high-loss size selection protocols, makes this protocol useful to researchers wishing to investigate whole transcriptomes.
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Affiliation(s)
- Nikita Potemkin
- Department of Anatomy, School of Biomedical Sciences, University of Otago, P.O. Box 56, Dunedin, New Zealand
- Brain Health Research Centre, Brain Research New Zealand-Rangahau Roro Aotearoa, University of Otago, Dunedin, New Zealand
| | - Sophie M F Cawood
- Department of Anatomy, School of Biomedical Sciences, University of Otago, P.O. Box 56, Dunedin, New Zealand
- Brain Health Research Centre, Brain Research New Zealand-Rangahau Roro Aotearoa, University of Otago, Dunedin, New Zealand
| | - Jackson Treece
- Department of Anatomy, School of Biomedical Sciences, University of Otago, P.O. Box 56, Dunedin, New Zealand
| | - Diane Guévremont
- Department of Anatomy, School of Biomedical Sciences, University of Otago, P.O. Box 56, Dunedin, New Zealand
- Brain Health Research Centre, Brain Research New Zealand-Rangahau Roro Aotearoa, University of Otago, Dunedin, New Zealand
| | - Christy J Rand
- Department of Anatomy, School of Biomedical Sciences, University of Otago, P.O. Box 56, Dunedin, New Zealand
| | - Catriona McLean
- Victorian Brain Bank, The Florey Institute of Neuroscience and Mental Health, Melbourne, VIC, Australia
- Anatomical Pathology, The Alfred Hospital, Melbourne, VIC, Australia
| | - Jo-Ann L Stanton
- Department of Anatomy, School of Biomedical Sciences, University of Otago, P.O. Box 56, Dunedin, New Zealand
| | - Joanna M Williams
- Department of Anatomy, School of Biomedical Sciences, University of Otago, P.O. Box 56, Dunedin, New Zealand.
- Brain Health Research Centre, Brain Research New Zealand-Rangahau Roro Aotearoa, University of Otago, Dunedin, New Zealand.
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18
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Baldini L, Robert A, Charpentier B, Labialle S. Phylogenetic and molecular analyses identify SNORD116 targets involved in the Prader Willi syndrome. Mol Biol Evol 2021; 39:6454102. [PMID: 34893870 PMCID: PMC8789076 DOI: 10.1093/molbev/msab348] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
The eutherian-specific SNORD116 family of repeated box C/D snoRNA genes is suspected to play a major role in the Prader–Willi syndrome (PWS), yet its molecular function remains poorly understood. Here, we combined phylogenetic and molecular analyses to identify candidate RNA targets. Based on the analysis of several eutherian orthologs, we found evidence of extensive birth-and-death and conversion events during SNORD116 gene history. However, the consequences for phylogenetic conservation were heterogeneous along the gene sequence. The standard snoRNA elements necessary for RNA stability and association with dedicated core proteins were the most conserved, in agreement with the hypothesis that SNORD116 generate genuine snoRNAs. In addition, one of the two antisense elements typically involved in RNA target recognition was largely dominated by a unique sequence present in at least one subset of gene paralogs in most species, likely the result of a selective effect. In agreement with a functional role, this ASE exhibited a hybridization capacity with putative mRNA targets that was strongly conserved in eutherians. Moreover, transient downregulation experiments in human cells showed that Snord116 controls the expression and splicing levels of these mRNAs. The functions of two of them, diacylglycerol kinase kappa and Neuroligin 3, extend the description of the molecular bases of PWS and reveal unexpected molecular links with the Fragile X syndrome and autism spectrum disorders.
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Affiliation(s)
- Laeya Baldini
- Université de Lorraine, CNRS, IMoPA, F-54000 Nancy, France
| | - Anne Robert
- Université de Lorraine, CNRS, IMoPA, F-54000 Nancy, France
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Xu H, Nottingham RM, Lambowitz AM. TGIRT-seq Protocol for the Comprehensive Profiling of Coding and Non-coding RNA Biotypes in Cellular, Extracellular Vesicle, and Plasma RNAs. Bio Protoc 2021; 11:e4239. [PMID: 35005084 PMCID: PMC8678547 DOI: 10.21769/bioprotoc.4239] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Revised: 09/01/2021] [Accepted: 09/22/2021] [Indexed: 09/12/2023] Open
Abstract
High-throughput RNA sequencing (RNA-seq) has extraordinarily advanced our understanding of gene expression and disease etiology, and is a powerful tool for the identification of biomarkers in a wide range of organisms. However, most RNA-seq methods rely on retroviral reverse transcriptases (RTs), enzymes that have inherently low fidelity and processivity, to convert RNAs into cDNAs for sequencing. Here, we describe an RNA-seq protocol using Thermostable Group II Intron Reverse Transcriptases (TGIRTs), which have high fidelity, processivity, and strand-displacement activity, as well as a proficient template-switching activity that enables efficient and seamless RNA-seq adapter addition. By combining these activities, TGIRT-seq enables the simultaneous profiling of all RNA biotypes from small amounts of starting material, with superior RNA-seq metrics, and unprecedented ability to sequence structured RNAs. The TGIRT-seq protocol for Illumina sequencing consists of three steps: (i) addition of a 3' RNA-seq adapter, coupled to the initiation of cDNA synthesis at the 3' end of a target RNA, via template switching from a synthetic adapter RNA/DNA starter duplex; (ii) addition of a 5' RNA-seq adapter, by using thermostable 5' App DNA/RNA ligase to ligate an adapter oligonucleotide to the 3' end of the completed cDNA; (iii) minimal PCR amplification, to add capture sites and indices for Illumina sequencing. TGIRT-seq for the Illumina sequencing platform has been used for comprehensive profiling of coding and non-coding RNAs in ribodepleted, chemically fragmented cellular RNAs, and for the analysis of intact (non-chemically fragmented) cellular, extracellular vesicle (EV), and plasma RNAs, where it yields continuous full-length end-to-end sequences of structured small non-coding RNAs (sncRNAs), including tRNAs, snoRNAs, snRNAs, pre-miRNAs, and full-length excised linear intron (FLEXI) RNAs. Graphic abstract: Figure 1.Overview of the TGIRT-seq protocol for Illumina sequencing.Major steps are: (1) Template switching from a synthetic R2 RNA/R2R DNA starter duplex with a 1-nt 3' DNA overhang (a mixture of A, C, G, and T residues, denoted N) that base pairs to the 3' nucleotide of a target RNA, and upon initiating reverse transcription by adding dNTPs, seamlessly links an R2R adapter to the 5' end of the resulting cDNA; (2) Ligation of an R1R adapter to the 3' end of the completed cDNA; and (3) Minimal PCR amplification with primers that add Illumina capture sites (P5 and P7) and barcode sequences (indices 5 and 7). The index 7 barcode is required, while the index 5 barcode is optional, to provide unique dual indices (UDIs).
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Affiliation(s)
- Hengyi Xu
- Departments of Molecular Biosciences and Oncology, University of Texas at Austin, Austin, Texas, 78712, USA
| | - Ryan M. Nottingham
- Departments of Molecular Biosciences and Oncology, University of Texas at Austin, Austin, Texas, 78712, USA
| | - Alan M. Lambowitz
- Departments of Molecular Biosciences and Oncology, University of Texas at Austin, Austin, Texas, 78712, USA
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20
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Ansell BRE, Thomas SN, Bonelli R, Munro JE, Freytag S, Bahlo M. A survey of RNA editing at single-cell resolution links interneurons to schizophrenia and autism. RNA (NEW YORK, N.Y.) 2021; 27:1482-1496. [PMID: 34535545 PMCID: PMC8594476 DOI: 10.1261/rna.078804.121] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Accepted: 09/12/2021] [Indexed: 06/13/2023]
Abstract
Conversion of adenosine to inosine in RNA by ADAR enzymes, termed "RNA editing," is essential for healthy brain development. Editing is dysregulated in neuropsychiatric diseases, but has not yet been investigated at scale at the level of individual neurons. We quantified RNA editing sites in nuclear transcriptomes of 3055 neurons from six cortical regions of a neurotypical female donor, and found 41,930 sites present in at least ten nuclei. Most sites were located within Alu repeats in introns or 3' UTRs, and approximately 80% were cataloged in public RNA editing databases. We identified 9285 putative novel editing sites, 29% of which were also detectable in unrelated donors. Intersection with results from bulk RNA-seq studies provided cell-type and spatial context for 1730 sites that are differentially edited in schizophrenic brain donors, and 910 such sites in autistic donors. Autism-related genes were also enriched with editing sites predicted to modify RNA structure. Inhibitory neurons showed higher overall transcriptome editing than excitatory neurons, and the highest editing rates were observed in the frontal cortex. We used generalized linear models to identify differentially edited sites and genes between cell types. Twenty nine genes were preferentially edited in excitatory neurons, and 43 genes were edited more heavily in inhibitory neurons, including RBFOX1, its target genes, and genes in the autism-associated Prader-Willi locus (15q11). The abundance of SNORD115/116 genes from locus 15q11 was positively associated with editing activity across the transcriptome. We contend that insufficient editing of autism-related genes in inhibitory neurons may contribute to the specific perturbation of those cells in autism.
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Affiliation(s)
- Brendan Robert E Ansell
- Population Health and Immunity Division, Walter and Eliza Hall Institute of Medical Research, Parkville 3052, Victoria, Australia
- Department of Medical Biology, University of Melbourne, Parkville 3052, Victoria, Australia
| | - Simon N Thomas
- Population Health and Immunity Division, Walter and Eliza Hall Institute of Medical Research, Parkville 3052, Victoria, Australia
- Department of Medical Biology, University of Melbourne, Parkville 3052, Victoria, Australia
| | - Roberto Bonelli
- Population Health and Immunity Division, Walter and Eliza Hall Institute of Medical Research, Parkville 3052, Victoria, Australia
- Department of Medical Biology, University of Melbourne, Parkville 3052, Victoria, Australia
| | - Jacob E Munro
- Population Health and Immunity Division, Walter and Eliza Hall Institute of Medical Research, Parkville 3052, Victoria, Australia
- Department of Medical Biology, University of Melbourne, Parkville 3052, Victoria, Australia
| | - Saskia Freytag
- Molecular Medicine Division, Harry Perkins Institute of Medical Research, Nedlands 6009, Western Australia, Australia
| | - Melanie Bahlo
- Population Health and Immunity Division, Walter and Eliza Hall Institute of Medical Research, Parkville 3052, Victoria, Australia
- Department of Medical Biology, University of Melbourne, Parkville 3052, Victoria, Australia
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21
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Sweeney BA, Tagmazian AA, Ribas CE, Finn RD, Bateman A, Petrov AI. Exploring Non-Coding RNAs in RNAcentral. ACTA ACUST UNITED AC 2021; 71:e104. [PMID: 32846052 DOI: 10.1002/cpbi.104] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Non-coding RNAs are essential for all life and carry out a wide range of functions. Information about these molecules is distributed across dozens of specialized resources. RNAcentral is a database of non-coding RNA sequences that provides a unified access point to non-coding RNA annotations from >40 member databases and helps provide insight into the function of these RNAs. This article describes different ways of accessing the data, including searching the website and retrieving the data programmatically over web APIs and a public database. We also demonstrate an example Galaxy workflow for using RNAcentral for RNA-seq differential expression analysis. RNAcentral is available at https://rnacentral.org. © 2020 The Authors. Basic Protocol 1: Viewing RNAcentral sequence reports Basic Protocol 2: Using RNAcentral text search to explore ncRNA sequences Basic Protocol 3: Using RNAcentral sequence search Basic Protocol 4: Using RNAcentral FTP archive Support Protocol 1: Using web APIs for programmatic data access Support Protocol 2: Using public Postgres database to export large datasets Support Protocol 3: Analyze non-coding RNA in RNA-seq datasets using RNAcentral and Galaxy.
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Affiliation(s)
- Blake A Sweeney
- European Molecular Biology Laboratory, European Bioinformatics Institute, Wellcome Genome Campus, Hinxton, Cambridge, UK
| | - Arina A Tagmazian
- European Molecular Biology Laboratory, European Bioinformatics Institute, Wellcome Genome Campus, Hinxton, Cambridge, UK.,Federal State Budget Scientific Institution Center of Experimental Embryology and Reproductive Biotechnologies, Moscow, Russia
| | - Carlos E Ribas
- European Molecular Biology Laboratory, European Bioinformatics Institute, Wellcome Genome Campus, Hinxton, Cambridge, UK
| | - Robert D Finn
- European Molecular Biology Laboratory, European Bioinformatics Institute, Wellcome Genome Campus, Hinxton, Cambridge, UK
| | - Alex Bateman
- European Molecular Biology Laboratory, European Bioinformatics Institute, Wellcome Genome Campus, Hinxton, Cambridge, UK
| | - Anton I Petrov
- European Molecular Biology Laboratory, European Bioinformatics Institute, Wellcome Genome Campus, Hinxton, Cambridge, UK
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Structural basis for template switching by a group II intron-encoded non-LTR-retroelement reverse transcriptase. J Biol Chem 2021; 297:100971. [PMID: 34280434 PMCID: PMC8363836 DOI: 10.1016/j.jbc.2021.100971] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2021] [Revised: 06/30/2021] [Accepted: 07/15/2021] [Indexed: 12/02/2022] Open
Abstract
Reverse transcriptases (RTs) can switch template strands during complementary DNA synthesis, enabling them to join discontinuous nucleic acid sequences. Template switching (TS) plays crucial roles in retroviral replication and recombination, is used for adapter addition in RNA-Seq, and may contribute to retroelement fitness by increasing evolutionary diversity and enabling continuous complementary DNA synthesis on damaged templates. Here, we determined an X-ray crystal structure of a TS complex of a group II intron RT bound simultaneously to an acceptor RNA and donor RNA template–DNA primer heteroduplex with a 1-nt 3′-DNA overhang. The structure showed that the 3′ end of the acceptor RNA binds in a pocket formed by an N-terminal extension present in non–long terminal repeat–retroelement RTs and the RT fingertips loop, with the 3′ nucleotide of the acceptor base paired to the 1-nt 3′-DNA overhang and its penultimate nucleotide base paired to the incoming dNTP at the RT active site. Analysis of structure-guided mutations identified amino acids that contribute to acceptor RNA binding and a phenylalanine residue near the RT active site that mediates nontemplated nucleotide addition. Mutation of the latter residue decreased multiple sequential template switches in RNA-Seq. Our results provide new insights into the mechanisms of TS and nontemplated nucleotide addition by RTs, suggest how these reactions could be improved for RNA-Seq, and reveal common structural features for TS by non–long terminal repeat–retroelement RTs and viral RNA–dependent RNA polymerases.
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23
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Bergeron D, Laforest C, Carpentier S, Calvé A, Fafard-Couture É, Deschamps-Francoeur G, Scott MS. SnoRNA copy regulation affects family size, genomic location and family abundance levels. BMC Genomics 2021; 22:414. [PMID: 34090325 PMCID: PMC8178906 DOI: 10.1186/s12864-021-07757-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2021] [Accepted: 05/26/2021] [Indexed: 12/03/2022] Open
Abstract
Background Small nucleolar RNAs (snoRNAs) are an abundant class of noncoding RNAs present in all eukaryotes and best known for their involvement in ribosome biogenesis. In mammalian genomes, many snoRNAs exist in multiple copies, resulting from recombination and retrotransposition from an ancestral snoRNA. To gain insight into snoRNA copy regulation, we used Rfam classification and normal human tissue expression datasets generated using low structure bias RNA-seq to characterize snoRNA families. Results We found that although box H/ACA families are on average larger than box C/D families, the number of expressed members is similar for both types. Family members can cover a wide range of average abundance values, but importantly, expression variability of individual members of a family is preferred over the total variability of the family, especially for box H/ACA snoRNAs, suggesting that while members are likely differentially regulated, mechanisms exist to ensure uniformity of the total family abundance across tissues. Box C/D snoRNA family members are mostly embedded in the same host gene while box H/ACA family members tend to be encoded in more than one different host, supporting a model in which box C/D snoRNA duplication occurred mostly by cis recombination while box H/ACA snoRNA families have gained copy members through retrotransposition. And unexpectedly, snoRNAs encoded in the same host gene can be regulated independently, as some snoRNAs within the same family vary in abundance in a divergent way between tissues. Conclusions SnoRNA copy regulation affects family sizes, genomic location of the members and controls simultaneously member and total family abundance to respond to the needs of individual tissues. Supplementary Information The online version contains supplementary material available at 10.1186/s12864-021-07757-1.
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Affiliation(s)
- Danny Bergeron
- Département de biochimie et de génomique fonctionnelle, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, Québec, J1E 4K8, Canada
| | - Cédric Laforest
- Département de biochimie et de génomique fonctionnelle, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, Québec, J1E 4K8, Canada
| | - Stacey Carpentier
- Département de biochimie et de génomique fonctionnelle, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, Québec, J1E 4K8, Canada
| | - Annabelle Calvé
- Département de biochimie et de génomique fonctionnelle, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, Québec, J1E 4K8, Canada
| | - Étienne Fafard-Couture
- Département de biochimie et de génomique fonctionnelle, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, Québec, J1E 4K8, Canada
| | - Gabrielle Deschamps-Francoeur
- Département de biochimie et de génomique fonctionnelle, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, Québec, J1E 4K8, Canada
| | - Michelle S Scott
- Département de biochimie et de génomique fonctionnelle, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, Québec, J1E 4K8, Canada.
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Fafard-Couture É, Bergeron D, Couture S, Abou-Elela S, Scott MS. Annotation of snoRNA abundance across human tissues reveals complex snoRNA-host gene relationships. Genome Biol 2021; 22:172. [PMID: 34088344 PMCID: PMC8176728 DOI: 10.1186/s13059-021-02391-2] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Accepted: 05/26/2021] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND Small nucleolar RNAs (snoRNAs) are mid-size non-coding RNAs required for ribosomal RNA modification, implying a ubiquitous tissue distribution linked to ribosome synthesis. However, increasing numbers of studies identify extra-ribosomal roles of snoRNAs in modulating gene expression, suggesting more complex snoRNA abundance patterns. Therefore, there is a great need for mapping the snoRNome in different human tissues as the blueprint for snoRNA functions. RESULTS We used a low structure bias RNA-Seq approach to accurately quantify snoRNAs and compare them to the entire transcriptome in seven healthy human tissues (breast, ovary, prostate, testis, skeletal muscle, liver, and brain). We identify 475 expressed snoRNAs categorized in two abundance classes that differ significantly in their function, conservation level, and correlation with their host gene: 390 snoRNAs are uniformly expressed and 85 are enriched in the brain or reproductive tissues. Most tissue-enriched snoRNAs are embedded in lncRNAs and display strong correlation of abundance with them, whereas uniformly expressed snoRNAs are mostly embedded in protein-coding host genes and are mainly non- or anticorrelated with them. Fifty-nine percent of the non-correlated or anticorrelated protein-coding host gene/snoRNA pairs feature dual-initiation promoters, compared to only 16% of the correlated non-coding host gene/snoRNA pairs. CONCLUSIONS Our results demonstrate that snoRNAs are not a single homogeneous group of housekeeping genes but include highly regulated tissue-enriched RNAs. Indeed, our work indicates that the architecture of snoRNA host genes varies to uncouple the host and snoRNA expressions in order to meet the different snoRNA abundance levels and functional needs of human tissues.
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Affiliation(s)
- Étienne Fafard-Couture
- Département de biochimie et de génomique fonctionnelle, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, Québec, J1E 4 K8, Canada
| | - Danny Bergeron
- Département de biochimie et de génomique fonctionnelle, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, Québec, J1E 4 K8, Canada
| | - Sonia Couture
- Département de microbiologie et d'infectiologie, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, Québec, J1E 4 K8, Canada
| | - Sherif Abou-Elela
- Département de microbiologie et d'infectiologie, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, Québec, J1E 4 K8, Canada.
| | - Michelle S Scott
- Département de biochimie et de génomique fonctionnelle, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, Québec, J1E 4 K8, Canada.
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25
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Nagai A, Mori K, Shiomi Y, Yoshihisa T. OTTER, a new method quantifying absolute amounts of tRNAs. RNA (NEW YORK, N.Y.) 2021; 27:rna.076489.120. [PMID: 33674420 PMCID: PMC8051270 DOI: 10.1261/rna.076489.120] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Accepted: 02/27/2021] [Indexed: 05/03/2023]
Abstract
To maintain optimal proteome, both codon choice of each mRNA and supply of aminoacyl-tRNAs are two principal factors in translation. Recent reports have revealed that the amounts of tRNAs in cells are more dynamic than we had expected. High-throughput methods such as RNA-Seq and microarrays are versatile for comprehensive detection of changes in individual tRNA amounts, but they suffer from inability to assess signal production efficiencies of individual tRNA species. Thus, they are not the perfect choice to measure absolute amounts of tRNAs. Here, we introduce a novel method for this purpose, termed Oligonucleotide-directed Three-prime Terminal Extension of RNA (OTTER), which employs fluorescence-labeling at the 3'-terminus of a tRNA by optimized reverse primer extension and an assessment step of each labeling efficiency by northern blotting. Using this method, we quantified the absolute amounts of the 34 individual and 4 pairs of isoacceptor tRNAs out of the total 42 nuclear-encoded isoacceptors in the yeast Saccharomyces cerevisiae. We found that the amounts of tRNAs in log phase yeast cells grown in a rich glucose medium range from 0.030 to 0.73 pmol/µg RNA. The tRNA amounts seem to be altered at the isoacceptor level by a few folds in response to physiological growing conditions. The data obtained by OTTER are poorly correlated with those by simple RNA-Seq, marginally with those by microarrays and by microscale thermophoresis. However, the OTTER data showed good agreement with the data obtained by 2D-gel analysis of in vivo radiolabeled RNAs. Thus, OTTER is a suitable method for quantifying absolute amounts of tRNAs at the level of isoacceptor resolution.
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Affiliation(s)
- Akihisa Nagai
- Graduate School of Life Science, University of Hyogo
| | - Kohei Mori
- Graduate School of Life Science, University of Hyogo
| | - Yuma Shiomi
- Graduate School of Life Science, University of Hyogo
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26
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Small nucleolar RNAs: continuing identification of novel members and increasing diversity of their molecular mechanisms of action. Biochem Soc Trans 2021; 48:645-656. [PMID: 32267490 PMCID: PMC7200641 DOI: 10.1042/bst20191046] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2020] [Revised: 03/17/2020] [Accepted: 03/19/2020] [Indexed: 12/11/2022]
Abstract
Identified five decades ago amongst the most abundant cellular RNAs, small nucleolar RNAs (snoRNAs) were initially described as serving as guides for the methylation and pseudouridylation of ribosomal RNA through direct base pairing. In recent years, however, increasingly powerful high-throughput genomic approaches and strategies have led to the discovery of many new members of the family and surprising diversity in snoRNA functionality and mechanisms of action. SnoRNAs are now known to target RNAs of many biotypes for a wider range of modifications, interact with diverse binding partners, compete with other binders for functional interactions, recruit diverse players to targets and affect protein function and accessibility through direct interaction. This mini-review presents the continuing characterization of the snoRNome through the identification of new snoRNA members and the discovery of their mechanisms of action, revealing a highly versatile noncoding family playing central regulatory roles and connecting the main cellular processes.
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27
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Kuo RI, Cheng Y, Zhang R, Brown JWS, Smith J, Archibald AL, Burt DW. Illuminating the dark side of the human transcriptome with long read transcript sequencing. BMC Genomics 2020; 21:751. [PMID: 33126848 PMCID: PMC7596999 DOI: 10.1186/s12864-020-07123-7] [Citation(s) in RCA: 68] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Accepted: 10/06/2020] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND The human transcriptome annotation is regarded as one of the most complete of any eukaryotic species. However, limitations in sequencing technologies have biased the annotation toward multi-exonic protein coding genes. Accurate high-throughput long read transcript sequencing can now provide additional evidence for rare transcripts and genes such as mono-exonic and non-coding genes that were previously either undetectable or impossible to differentiate from sequencing noise. RESULTS We developed the Transcriptome Annotation by Modular Algorithms (TAMA) software to leverage the power of long read transcript sequencing and address the issues with current data processing pipelines. TAMA achieved high sensitivity and precision for gene and transcript model predictions in both reference guided and unguided approaches in our benchmark tests using simulated Pacific Biosciences (PacBio) and Nanopore sequencing data and real PacBio datasets. By analyzing PacBio Sequel II Iso-Seq sequencing data of the Universal Human Reference RNA (UHRR) using TAMA and other commonly used tools, we found that the convention of using alignment identity to measure error correction performance does not reflect actual gain in accuracy of predicted transcript models. In addition, inter-read error correction can cause major changes to read mapping, resulting in potentially over 6 K erroneous gene model predictions in the Iso-Seq based human genome annotation. Using TAMA's genome assembly based error correction and gene feature evidence, we predicted 2566 putative novel non-coding genes and 1557 putative novel protein coding gene models. CONCLUSIONS Long read transcript sequencing data has the power to identify novel genes within the highly annotated human genome. The use of parameter tuning and extensive output information of the TAMA software package allows for in depth exploration of eukaryotic transcriptomes. We have found long read data based evidence for thousands of unannotated genes within the human genome. More development in sequencing library preparation and data processing are required for differentiating sequencing noise from real genes in long read RNA sequencing data.
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Affiliation(s)
- Richard I Kuo
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Midlothian, EH25 9RG, UK.
| | - Yuanyuan Cheng
- The University of Queensland, St. Lucia, Brisbane, QLD, 4072, Australia
- School of Life and Environmental Sciences, University of Sydney, Sydney, New South Wales, Australia
| | - Runxuan Zhang
- Information and Computational Sciences, The James Hutton Institute, Invergowrie, Dundee, Scotland, UK
| | - John W S Brown
- Plant Sciences Division, School of Life Sciences, University of Dundee, Invergowrie, Dundee, Scotland, UK
- Cell and Molecular Sciences, The James Hutton Institute, Invergowrie, Dundee, Scotland, UK
| | - Jacqueline Smith
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Midlothian, EH25 9RG, UK
| | - Alan L Archibald
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Midlothian, EH25 9RG, UK
| | - David W Burt
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Midlothian, EH25 9RG, UK
- The University of Queensland, St. Lucia, Brisbane, QLD, 4072, Australia
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28
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Yao J, Wu DC, Nottingham RM, Lambowitz AM. Identification of protein-protected mRNA fragments and structured excised intron RNAs in human plasma by TGIRT-seq peak calling. eLife 2020; 9:e60743. [PMID: 32876046 PMCID: PMC7518892 DOI: 10.7554/elife.60743] [Citation(s) in RCA: 16] [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: 07/06/2020] [Accepted: 09/01/2020] [Indexed: 12/18/2022] Open
Abstract
Human plasma contains > 40,000 different coding and non-coding RNAs that are potential biomarkers for human diseases. Here, we used thermostable group II intron reverse transcriptase sequencing (TGIRT-seq) combined with peak calling to simultaneously profile all RNA biotypes in apheresis-prepared human plasma pooled from healthy individuals. Extending previous TGIRT-seq analysis, we found that human plasma contains largely fragmented mRNAs from > 19,000 protein-coding genes, abundant full-length, mature tRNAs and other structured small non-coding RNAs, and less abundant tRNA fragments and mature and pre-miRNAs. Many of the mRNA fragments identified by peak calling correspond to annotated protein-binding sites and/or have stable predicted secondary structures that could afford protection from plasma nucleases. Peak calling also identified novel repeat RNAs, miRNA-sized RNAs, and putatively structured intron RNAs of potential biological, evolutionary, and biomarker significance, including a family of full-length excised intron RNAs, subsets of which correspond to mirtron pre-miRNAs or agotrons.
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Affiliation(s)
- Jun Yao
- Institute for Cellular and Molecular Biology and Departments of Molecular Biosciences and Oncology, University of TexasAustinUnited States
| | - Douglas C Wu
- Institute for Cellular and Molecular Biology and Departments of Molecular Biosciences and Oncology, University of TexasAustinUnited States
| | - Ryan M Nottingham
- Institute for Cellular and Molecular Biology and Departments of Molecular Biosciences and Oncology, University of TexasAustinUnited States
| | - Alan M Lambowitz
- Institute for Cellular and Molecular Biology and Departments of Molecular Biosciences and Oncology, University of TexasAustinUnited States
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29
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Martín-Alonso S, Frutos-Beltrán E, Menéndez-Arias L. Reverse Transcriptase: From Transcriptomics to Genome Editing. Trends Biotechnol 2020; 39:194-210. [PMID: 32653101 DOI: 10.1016/j.tibtech.2020.06.008] [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: 05/19/2020] [Revised: 06/10/2020] [Accepted: 06/15/2020] [Indexed: 01/01/2023]
Abstract
Reverse transcriptases (RTs) are enzymes that can generate a complementary strand of DNA (cDNA) from RNA. Coupled with PCR, RTs have been widely used to detect RNAs and to clone expressed genes. Classical retroviral RTs have been improved by protein engineering. These enzymes and newly characterized RTs are key elements in the development of next-generation sequencing techniques that are now being applied to the study of transcriptomics. In addition, engineered RTs fused to a CRISPR/Cas9 nickase have recently shown great potential as tools to manipulate eukaryotic genomes. In this review, we discuss the properties and uses of wild type and engineered RTs in biotechnological applications, from conventional RT-PCR to recently introduced prime editing.
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Affiliation(s)
- Samara Martín-Alonso
- Centro de Biología Molecular 'Severo Ochoa' (Consejo Superior de Investigaciones Científicas and Universidad Autónoma de Madrid), c/ Nicolás Cabrera 1, Campus de Cantoblanco-UAM, 28049 Madrid, Spain
| | - Estrella Frutos-Beltrán
- Centro de Biología Molecular 'Severo Ochoa' (Consejo Superior de Investigaciones Científicas and Universidad Autónoma de Madrid), c/ Nicolás Cabrera 1, Campus de Cantoblanco-UAM, 28049 Madrid, Spain
| | - Luis Menéndez-Arias
- Centro de Biología Molecular 'Severo Ochoa' (Consejo Superior de Investigaciones Científicas and Universidad Autónoma de Madrid), c/ Nicolás Cabrera 1, Campus de Cantoblanco-UAM, 28049 Madrid, Spain. @cbm.csic.es
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30
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Deschamps-Francoeur G, Boivin V, Abou Elela S, Scott MS. CoCo: RNA-seq read assignment correction for nested genes and multimapped reads. Bioinformatics 2020; 35:5039-5047. [PMID: 31141144 PMCID: PMC6901076 DOI: 10.1093/bioinformatics/btz433] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2018] [Revised: 01/26/2019] [Accepted: 05/24/2019] [Indexed: 01/01/2023] Open
Abstract
Motivation Next-generation sequencing techniques revolutionized the study of RNA expression by permitting whole transcriptome analysis. However, sequencing reads generated from nested and multi-copy genes are often either misassigned or discarded, which greatly reduces both quantification accuracy and gene coverage. Results Here we present count corrector (CoCo), a read assignment pipeline that takes into account the multitude of overlapping and repetitive genes in the transcriptome of higher eukaryotes. CoCo uses a modified annotation file that highlights nested genes and proportionally distributes multimapped reads between repeated sequences. CoCo salvages over 15% of discarded aligned RNA-seq reads and significantly changes the abundance estimates for both coding and non-coding RNA as validated by PCR and bedgraph comparisons. Availability and implementation The CoCo software is an open source package written in Python and available from http://gitlabscottgroup.med.usherbrooke.ca/scott-group/coco. Supplementary information Supplementary data are available at Bioinformatics online.
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Affiliation(s)
| | - Vincent Boivin
- Department of Biochemistry and RNA Group, Université de Sherbrooke, Sherbrooke, QC, Canada
| | - Sherif Abou Elela
- Department of Microbiology and Infectiology, Faculty of Medicine and Health Sciences, Université de Sherbrooke, Sherbrooke, QC, Canada
| | - Michelle S Scott
- Department of Biochemistry and RNA Group, Université de Sherbrooke, Sherbrooke, QC, Canada
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31
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Deschamps-Francoeur G, Simoneau J, Scott MS. Handling multi-mapped reads in RNA-seq. Comput Struct Biotechnol J 2020; 18:1569-1576. [PMID: 32637053 PMCID: PMC7330433 DOI: 10.1016/j.csbj.2020.06.014] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2020] [Revised: 06/06/2020] [Accepted: 06/07/2020] [Indexed: 11/07/2022] Open
Abstract
Many eukaryotic genomes harbour large numbers of duplicated sequences, of diverse biotypes, resulting from several mechanisms including recombination, whole genome duplication and retro-transposition. Such repeated sequences complicate gene/transcript quantification during RNA-seq analysis due to reads mapping to more than one locus, sometimes involving genes embedded in other genes. Genes of different biotypes have dissimilar levels of sequence duplication, with long-noncoding RNAs and messenger RNAs sharing less sequence similarity to other genes than biotypes encoding shorter RNAs. Many strategies have been elaborated to handle these multi-mapped reads, resulting in increased accuracy in gene/transcript quantification, although separate tools are typically used to estimate the abundance of short and long genes due to their dissimilar characteristics. This review discusses the mechanisms leading to sequence duplication, the biotypes affected, the computational strategies employed to deal with multi-mapped reads and the challenges that still remain to be overcome.
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Affiliation(s)
- Gabrielle Deschamps-Francoeur
- Département de Biochimie et Génomique Fonctionnelle, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, QC J1E 4K8, Canada
| | - Joël Simoneau
- Département de Biochimie et Génomique Fonctionnelle, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, QC J1E 4K8, Canada
| | - Michelle S. Scott
- Département de Biochimie et Génomique Fonctionnelle, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, QC J1E 4K8, Canada
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32
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Bouchard-Bourelle P, Desjardins-Henri C, Mathurin-St-Pierre D, Deschamps-Francoeur G, Fafard-Couture É, Garant JM, Elela SA, Scott MS. snoDB: an interactive database of human snoRNA sequences, abundance and interactions. Nucleic Acids Res 2020; 48:D220-D225. [PMID: 31598696 PMCID: PMC6943035 DOI: 10.1093/nar/gkz884] [Citation(s) in RCA: 64] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2019] [Revised: 09/13/2019] [Accepted: 10/01/2019] [Indexed: 12/14/2022] Open
Abstract
Small nucleolar RNAs (snoRNAs) are an abundant type of non-coding RNA with conserved functions in all known eukaryotes. Classified into two main families, the box C/D and H/ACA snoRNAs, they enact their most well characterized role of guiding site specific modifications in ribosomal RNA, through the formation of specific ribonucleoprotein complexes, with fundamental implications in ribosome biogenesis. However, it is becoming increasingly clear that the landscape of snoRNA cellular functionality is much broader than it once seemed with novel members, non-uniform expression patterns, new and diverse targets as well as several emerging non-canonical functions ranging from the modulation of alternative splicing to the regulation of chromatin architecture. In order to facilitate the further characterization of human snoRNAs in a holistic manner, we introduce an online interactive database tool: snoDB. Its purpose is to consolidate information on human snoRNAs from different sources such as sequence databases, target information, both canonical and non-canonical from the literature and from high-throughput RNA-RNA interaction datasets, as well as high-throughput sequencing data that can be visualized interactively.
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Affiliation(s)
- Philia Bouchard-Bourelle
- Département de biochimie, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, Québec J1E 4K8, Canada
| | - Clément Desjardins-Henri
- Département de biochimie, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, Québec J1E 4K8, Canada
| | - Darren Mathurin-St-Pierre
- Département de biochimie, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, Québec J1E 4K8, Canada
| | - Gabrielle Deschamps-Francoeur
- Département de biochimie, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, Québec J1E 4K8, Canada
| | - Étienne Fafard-Couture
- Département de biochimie, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, Québec J1E 4K8, Canada
| | - Jean-Michel Garant
- Département de biochimie, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, Québec J1E 4K8, Canada
| | - Sherif Abou Elela
- Département de microbiologie et infectiologie, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, Québec J1E 4K8, Canada
| | - Michelle S Scott
- Département de biochimie, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, Québec J1E 4K8, Canada
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33
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Boivin V, Reulet G, Boisvert O, Couture S, Elela SA, Scott MS. Reducing the structure bias of RNA-Seq reveals a large number of non-annotated non-coding RNA. Nucleic Acids Res 2020; 48:2271-2286. [PMID: 31980822 PMCID: PMC7049693 DOI: 10.1093/nar/gkaa028] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2019] [Revised: 01/08/2020] [Accepted: 01/22/2020] [Indexed: 02/06/2023] Open
Abstract
The study of RNA expression is the fastest growing area of genomic research. However, despite the dramatic increase in the number of sequenced transcriptomes, we still do not have accurate estimates of the number and expression levels of non-coding RNA genes. Non-coding transcripts are often overlooked due to incomplete genome annotation. In this study, we use annotation-independent detection of RNA reads generated using a reverse transcriptase with low structure bias to identify non-coding RNA. Transcripts between 20 and 500 nucleotides were filtered and crosschecked with non-coding RNA annotations revealing 111 non-annotated non-coding RNAs expressed in different cell lines and tissues. Inspecting the sequence and structural features of these transcripts indicated that 60% of these transcripts correspond to new snoRNA and tRNA-like genes. The identified genes exhibited features of their respective families in terms of structure, expression, conservation and response to depletion of interacting proteins. Together, our data reveal a new group of RNA that are difficult to detect using standard gene prediction and RNA sequencing techniques, suggesting that reliance on actual gene annotation and sequencing techniques distorts the perceived architecture of the human transcriptome.
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Affiliation(s)
- Vincent Boivin
- Département de biochimie et génomique fonctionnelle, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, QC J1E 4K8, Canada
| | - Gaspard Reulet
- Département de biochimie et génomique fonctionnelle, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, QC J1E 4K8, Canada
| | - Olivier Boisvert
- Département de biochimie et génomique fonctionnelle, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, QC J1E 4K8, Canada
| | - Sonia Couture
- Département de biochimie et génomique fonctionnelle, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, QC J1E 4K8, Canada
| | - Sherif Abou Elela
- Département de microbiologie et d'infectiologie, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, QC J1E 4K8, Canada
| | - Michelle S Scott
- Département de biochimie et génomique fonctionnelle, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, QC J1E 4K8, Canada
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Schwenzer H, Jühling F, Chu A, Pallett LJ, Baumert TF, Maini M, Fassati A. Oxidative Stress Triggers Selective tRNA Retrograde Transport in Human Cells during the Integrated Stress Response. Cell Rep 2020; 26:3416-3428.e5. [PMID: 30893612 PMCID: PMC6426654 DOI: 10.1016/j.celrep.2019.02.077] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2018] [Revised: 02/04/2019] [Accepted: 02/20/2019] [Indexed: 01/05/2023] Open
Abstract
In eukaryotes, tRNAs are transcribed in the nucleus and exported to the cytosol, where they deliver amino acids to ribosomes for protein translation. This nuclear-cytoplasmic movement was believed to be unidirectional. However, active shuttling of tRNAs, named tRNA retrograde transport, between the cytosol and nucleus has been discovered. This pathway is conserved in eukaryotes, suggesting a fundamental function; however, little is known about its role in human cells. Here we report that, in human cells, oxidative stress triggers tRNA retrograde transport, which is rapid, reversible, and selective for certain tRNA species, mostly with shorter 3′ ends. Retrograde transport of tRNASeC, which promotes translation of selenoproteins required to maintain homeostatic redox levels in cells, is highly efficient. tRNA retrograde transport is regulated by the integrated stress response pathway via the PERK-REDD1-mTOR axis. Thus, we propose that tRNA retrograde transport is part of the cellular response to oxidative stress. Oxidative stress triggers nuclear import of cytoplasmic tRNAs Import is selective for certain tRNAs Import requires activation of the unfolded protein response and inhibition of mTOR via REDD1 tRNA nuclear import is a component of the integrated stress response
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Affiliation(s)
- Hagen Schwenzer
- Division of Infection and Immunity, University College London (UCL), London WC1E 6BT, UK
| | - Frank Jühling
- INSERM, U1110, Institut de Recherche sur les Maladies Virales et Hépatiques, 2 Université de Strasbourg, 67000 Strasbourg, France
| | - Alexander Chu
- Division of Infection and Immunity, University College London (UCL), London WC1E 6BT, UK
| | - Laura J Pallett
- Division of Infection and Immunity, University College London (UCL), London WC1E 6BT, UK
| | - Thomas F Baumert
- INSERM, U1110, Institut de Recherche sur les Maladies Virales et Hépatiques, 2 Université de Strasbourg, 67000 Strasbourg, France; Nouvel Hôpital Civil, Institut Hospitalo-Universitaire, 67000 Strasbourg, France
| | - Mala Maini
- Division of Infection and Immunity, University College London (UCL), London WC1E 6BT, UK
| | - Ariberto Fassati
- Division of Infection and Immunity, University College London (UCL), London WC1E 6BT, UK.
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35
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Lentzsch AM, Yao J, Russell R, Lambowitz AM. Template-switching mechanism of a group II intron-encoded reverse transcriptase and its implications for biological function and RNA-Seq. J Biol Chem 2019; 294:19764-19784. [PMID: 31712313 DOI: 10.1074/jbc.ra119.011337] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2019] [Revised: 11/01/2019] [Indexed: 12/18/2022] Open
Abstract
The reverse transcriptases (RTs) encoded by mobile group II introns and other non-LTR retroelements differ from retroviral RTs in being able to template-switch efficiently from the 5' end of one template to the 3' end of another with little or no complementarity between the donor and acceptor templates. Here, to establish a complete kinetic framework for the reaction and to identify conditions that more efficiently capture acceptor RNAs or DNAs, we used a thermostable group II intron RT (TGIRT; GsI-IIC RT) that can template switch directly from synthetic RNA template/DNA primer duplexes having either a blunt end or a 3'-DNA overhang end. We found that the rate and amplitude of template switching are optimal from starter duplexes with a single nucleotide 3'-DNA overhang complementary to the 3' nucleotide of the acceptor RNA, suggesting a role for nontemplated nucleotide addition of a complementary nucleotide to the 3' end of cDNAs synthesized from natural templates. Longer 3'-DNA overhangs progressively decreased the template-switching rate, even when complementary to the 3' end of the acceptor template. The reliance on only a single bp with the 3' nucleotide of the acceptor together with discrimination against mismatches and the high processivity of group II intron RTs enable synthesis of full-length DNA copies of nucleic acids beginning directly at their 3' end. We discuss the possible biological functions of the template-switching activity of group II intron- and other non-LTR retroelement-encoded RTs, as well as the optimization of this activity for adapter addition in RNA- and DNA-Seq protocols.
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Affiliation(s)
- Alfred M Lentzsch
- Institute for Cellular and Molecular Biology, Departments of Molecular Biosciences and Oncology, University of Texas at Austin, Austin, Texas 78712
| | - Jun Yao
- Institute for Cellular and Molecular Biology, Departments of Molecular Biosciences and Oncology, University of Texas at Austin, Austin, Texas 78712
| | - Rick Russell
- Institute for Cellular and Molecular Biology, Departments of Molecular Biosciences and Oncology, University of Texas at Austin, Austin, Texas 78712
| | - Alan M Lambowitz
- Institute for Cellular and Molecular Biology, Departments of Molecular Biosciences and Oncology, University of Texas at Austin, Austin, Texas 78712
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36
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Stark R, Grzelak M, Hadfield J. RNA sequencing: the teenage years. Nat Rev Genet 2019; 20:631-656. [DOI: 10.1038/s41576-019-0150-2] [Citation(s) in RCA: 679] [Impact Index Per Article: 135.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/18/2019] [Indexed: 12/12/2022]
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37
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Guffanti G, Bartlett A, Klengel T, Klengel C, Hunter R, Glinsky G, Macciardi F. Novel Bioinformatics Approach Identifies Transcriptional Profiles of Lineage-Specific Transposable Elements at Distinct Loci in the Human Dorsolateral Prefrontal Cortex. Mol Biol Evol 2019; 35:2435-2453. [PMID: 30053206 PMCID: PMC6188555 DOI: 10.1093/molbev/msy143] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Expression of transposable elements (TE) is transiently activated during human preimplantation embryogenesis in a developmental stage- and cell type-specific manner and TE-mediated epigenetic regulation is intrinsically wired in developmental genetic networks in human embryos and embryonic stem cells. However, there are no systematic studies devoted to a comprehensive analysis of the TE transcriptome in human adult organs and tissues, including human neural tissues. To investigate TE expression in the human Dorsolateral Prefrontal Cortex (DLPFC), we developed and validated a straightforward analytical approach to chart quantitative genome-wide expression profiles of all annotated TE loci based on unambiguous mapping of discrete TE-encoded transcripts using a de novo assembly strategy. To initially evaluate the potential regulatory impact of DLPFC-expressed TE, we adopted a comparative evolutionary genomics approach across humans, primates, and rodents to document conservation patterns, lineage-specificity, and colocalizations with transcription factor binding sites mapped within primate- and human-specific TE. We identified 654,665 transcripts expressed from 477,507 distinct loci of different TE classes and families, the majority of which appear to have originated from primate-specific sequences. We discovered 4,687 human-specific and transcriptionally active TEs in DLPFC, of which the prominent majority (80.2%) appears spliced. Our analyses revealed significant associations of DLPFC-expressed TE with primate- and human-specific transcription factor binding sites, suggesting potential cross-talks of concordant regulatory functions. We identified 1,689 TEs differentially expressed in the DLPFC of Schizophrenia patients, a majority of which is located within introns of 1,137 protein-coding genes. Our findings imply that identified DLPFC-expressed TEs may affect human brain structures and functions following different evolutionary trajectories. On one side, hundreds of thousands of TEs maintained a remarkably high conservation for ∼8 My of primates’ evolution, suggesting that they are likely conveying evolutionary-constrained primate-specific regulatory functions. In parallel, thousands of transcriptionally active human-specific TE loci emerged more recently, suggesting that they could be relevant for human-specific behavioral or cognitive functions.
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Affiliation(s)
- Guia Guffanti
- Department of Psychiatry, Harvard Medical School, Cambridge, MA.,Division of Depression and Anxiety, McLean Hospital, Belmont, MA
| | - Andrew Bartlett
- Department of Psychology, University of Massachusetts, Boston, MA
| | - Torsten Klengel
- Department of Psychiatry, Harvard Medical School, Cambridge, MA.,Division of Depression and Anxiety, McLean Hospital, Belmont, MA.,Department of Psychiatry and Psychotherapy, University Medical Center Göttingen, Georg-August-University, Goettingen, Germany
| | - Claudia Klengel
- Department of Psychiatry, Harvard Medical School, Cambridge, MA.,Division of Depression and Anxiety, McLean Hospital, Belmont, MA
| | - Richard Hunter
- Department of Psychology, University of Massachusetts, Boston, MA
| | - Gennadi Glinsky
- Translational & Functional Genomics, Institute of Engineering in Medicine, University of California San Diego, La Jolla, CA
| | - Fabio Macciardi
- Department of Psychiatry and Human Behavior, University of California Irvine, Irvine, CA
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38
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Improved TGIRT-seq methods for comprehensive transcriptome profiling with decreased adapter dimer formation and bias correction. Sci Rep 2019; 9:7953. [PMID: 31138886 PMCID: PMC6538698 DOI: 10.1038/s41598-019-44457-z] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2019] [Accepted: 05/17/2019] [Indexed: 02/08/2023] Open
Abstract
Thermostable group II intron reverse transcriptases (TGIRTs) with high fidelity and processivity have been used for a variety of RNA sequencing (RNA-seq) applications, including comprehensive profiling of whole-cell, exosomal, and human plasma RNAs; quantitative tRNA-seq based on the ability of TGIRT enzymes to give full-length reads of tRNAs and other structured small ncRNAs; high-throughput mapping of post-transcriptional modifications; and RNA structure mapping. Here, we improved TGIRT-seq methods for comprehensive transcriptome profiling by rationally designing RNA-seq adapters that minimize adapter dimer formation. Additionally, we developed biochemical and computational methods for remediating 5′- and 3′-end biases, the latter based on a random forest regression model that provides insight into the contribution of different factors to these biases. These improvements, some of which may be applicable to other RNA-seq methods, increase the efficiency of TGIRT-seq library construction and improve coverage of very small RNAs, such as miRNAs. Our findings provide insight into the biochemical basis of 5′- and 3′-end biases in RNA-seq and suggest general approaches for remediating biases and decreasing adapter dimer formation.
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39
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Grozhik AV, Jaffrey SR. Distinguishing RNA modifications from noise in epitranscriptome maps. Nat Chem Biol 2019; 14:215-225. [PMID: 29443978 DOI: 10.1038/nchembio.2546] [Citation(s) in RCA: 73] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2017] [Accepted: 12/04/2017] [Indexed: 12/26/2022]
Abstract
Messenger RNA (mRNA) and long noncoding RNA (lncRNA) can be subjected to a variety of post-transcriptional modifications that markedly influence their fate and function. This concept of 'epitranscriptomic' modifications and the understanding of their function has been driven by new technologies for transcriptome-wide mapping of modified nucleotides using next-generation sequencing. Mapping technologies have successfully documented the location and prevalence of several modified nucleotides in the transcriptome. However, some mapping methods have led to proposals of pervasive novel RNA modifications that have subsequently been shown to be exceptionally rare. These controversies have resulted in confusion about the identity of the modified nucleotides comprising the epitranscriptome in mRNA and lncRNA. Here we discuss the different transcriptome-wide technologies for mapping modified nucleotides. We describe why these methods can have poor accuracy and specificity. Finally, we describe emerging strategies that minimize false positives and other pitfalls associated with mapping and measuring epitranscriptomic modifications.
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Affiliation(s)
- Anya V Grozhik
- Department of Pharmacology, Weill Cornell Medicine, Cornell University, New York, New York, USA
| | - Samie R Jaffrey
- Department of Pharmacology, Weill Cornell Medicine, Cornell University, New York, New York, USA
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40
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Belfort M, Lambowitz AM. Group II Intron RNPs and Reverse Transcriptases: From Retroelements to Research Tools. Cold Spring Harb Perspect Biol 2019; 11:11/4/a032375. [PMID: 30936187 DOI: 10.1101/cshperspect.a032375] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Group II introns, self-splicing retrotransposons, serve as both targets of investigation into their structure, splicing, and retromobility and a source of tools for genome editing and RNA analysis. Here, we describe the first cryo-electron microscopy (cryo-EM) structure determination, at 3.8-4.5 Å, of a group II intron ribozyme complexed with its encoded protein, containing a reverse transcriptase (RT), required for RNA splicing and retromobility. We also describe a method called RIG-seq using a retrotransposon indicator gene for high-throughput integration profiling of group II introns and other retrotransposons. Targetrons, RNA-guided gene targeting agents widely used for bacterial genome engineering, are described next. Finally, we detail thermostable group II intron RTs, which synthesize cDNAs with high accuracy and processivity, for use in various RNA-seq applications and relate their properties to a 3.0-Å crystal structure of the protein poised for reverse transcription. Biological insights from these group II intron revelations are discussed.
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Affiliation(s)
- Marlene Belfort
- Department of Biological Sciences and RNA Institute, University at Albany, State University of New York, Albany, New York 12222
| | - Alan M Lambowitz
- Institute for Cellular and Molecular Biology and Department of Molecular Biosciences, University of Texas at Austin, Austin, Texas 78712
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41
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Abstract
Long double-stranded RNAs (dsRNAs) are abundantly expressed in animals, in which they frequently occur in introns and 3' untranslated regions of mRNAs. Functions of long, cellular dsRNAs are poorly understood, although deficiencies in adenosine deaminases that act on RNA, or ADARs, promote their recognition as viral dsRNA and an aberrant immune response. Diverse dsRNA-binding proteins bind cellular dsRNAs, hinting at additional roles. Understanding these roles is facilitated by mapping the genomic locations that express dsRNA in various tissues and organisms. ADAR editing provides a signature of dsRNA structure in cellular transcripts. In this review, we detail approaches to map ADAR editing sites and dsRNAs genome-wide, with particular focus on high-throughput sequencing methods and considerations for their successful application to the detection of editing sites and dsRNAs.
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Affiliation(s)
- Daniel P Reich
- Department of Biochemistry, University of Utah, Salt Lake City, Utah 84112
| | - Brenda L Bass
- Department of Biochemistry, University of Utah, Salt Lake City, Utah 84112
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42
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Stewart CM, Tsui DWY. Circulating cell-free DNA for non-invasive cancer management. Cancer Genet 2018; 228-229:169-179. [PMID: 29625863 PMCID: PMC6598437 DOI: 10.1016/j.cancergen.2018.02.005] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2017] [Revised: 02/19/2018] [Accepted: 02/23/2018] [Indexed: 01/06/2023]
Abstract
Cell-free DNA (cfDNA) was first identified in human plasma in 1948 and is thought to be released from cells throughout the body into the circulatory system. In cancer, a portion of the cfDNA originates from tumour cells, referred to as circulating-tumour DNA (ctDNA), and can contain mutations corresponding to the patient's tumour, for instance specific TP53 alleles. Profiling of cfDNA has recently become an area of increasing clinical relevance in oncology, in particular due to advances in the sensitivity of molecular biology techniques and development of next generation sequencing technologies, as this allows tumour mutations to be identified and tracked non-invasively. This has opened up new possibilities for monitoring tumour evolution and acquisition of resistance, as well as for guiding treatment decisions when tumour biopsy tissue is insufficient or unavailable. In this review, we will discuss the biology of cell-free nucleic acids, methods of analysis, and the potential clinical uses of these techniques, as well as the on-going clinical development of ctDNA assays.
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Affiliation(s)
- Caitlin M Stewart
- Marie-José and Henry R. Kravis Center for Molecular Oncology, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, Box 20, New York, NY 10065, USA; Department of Pathology, Memorial Sloan Kettering Cancer Center, New York, NY, USA
| | - Dana W Y Tsui
- Marie-José and Henry R. Kravis Center for Molecular Oncology, Memorial Sloan Kettering Cancer Center, 1275 York Avenue, Box 20, New York, NY 10065, USA; Department of Pathology, Memorial Sloan Kettering Cancer Center, New York, NY, USA.
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43
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Abstract
Investigations over the past eight years of chemical modifications on messenger RNA (mRNA) have revealed a new level of posttranscriptional gene regulation in eukaryotes. Rapid progress in our understanding of these modifications, particularly, N6-methyladenosine (m6A), has revealed their roles throughout the life cycle of an mRNA transcript. m6A methylation provides a rapid mechanism for coordinated transcriptome processing and turnover that is important in embryonic development and cell differentiation. In response to cellular signals, m6A can also regulate the translation of specific pools of transcripts. These mechanisms can be hijacked in human diseases, including numerous cancers and viral infection. Beyond m6A, many other mRNA modifications have been mapped in the transcriptome, but much less is known about their biological functions. As methods continue to be developed, we will be able to study these modifications both more broadly and in greater depth, which will likely reveal a wealth of new RNA biology.
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Affiliation(s)
- Sigrid Nachtergaele
- Department of Chemistry, Department of Biochemistry and Molecular Biology, Institute for Biophysical Dynamics, and Howard Hughes Medical Institute, University of Chicago, Chicago, Illinois 60637, USA; ,
| | - Chuan He
- Department of Chemistry, Department of Biochemistry and Molecular Biology, Institute for Biophysical Dynamics, and Howard Hughes Medical Institute, University of Chicago, Chicago, Illinois 60637, USA; ,
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44
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Mohr G, Silas S, Stamos JL, Makarova KS, Markham LM, Yao J, Lucas-Elío P, Sanchez-Amat A, Fire AZ, Koonin EV, Lambowitz AM. A Reverse Transcriptase-Cas1 Fusion Protein Contains a Cas6 Domain Required for Both CRISPR RNA Biogenesis and RNA Spacer Acquisition. Mol Cell 2018; 72:700-714.e8. [PMID: 30344094 PMCID: PMC6242336 DOI: 10.1016/j.molcel.2018.09.013] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2018] [Revised: 08/10/2018] [Accepted: 09/12/2018] [Indexed: 01/30/2023]
Abstract
Prokaryotic CRISPR-Cas systems provide adaptive immunity by integrating portions of foreign nucleic acids (spacers) into genomic CRISPR arrays. Cas6 proteins then process CRISPR array transcripts into spacer-derived RNAs (CRISPR RNAs; crRNAs) that target Cas nucleases to matching invaders. We find that a Marinomonas mediterranea fusion protein combines three enzymatic domains (Cas6, reverse transcriptase [RT], and Cas1), which function in both crRNA biogenesis and spacer acquisition from RNA and DNA. We report a crystal structure of this divergent Cas6, identify amino acids required for Cas6 activity, show that the Cas6 domain is required for RT activity and RNA spacer acquisition, and demonstrate that CRISPR-repeat binding to Cas6 regulates RT activity. Co-evolution of putative interacting surfaces suggests a specific structural interaction between the Cas6 and RT domains, and phylogenetic analysis reveals repeated, stable association of free-standing Cas6s with CRISPR RTs in multiple microbial lineages, indicating that a functional interaction between these proteins preceded evolution of the fusion.
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Affiliation(s)
- Georg Mohr
- Institute for Cellular and Molecular Biology and Department of Molecular Biosciences, University of Texas at Austin, Austin, TX 78712, USA
| | - Sukrit Silas
- Department of Pathology, Stanford University, Stanford, CA 94305, USA; Department of Chemical and Systems Biology, Stanford University, Stanford, CA 94305, USA
| | - Jennifer L Stamos
- Institute for Cellular and Molecular Biology and Department of Molecular Biosciences, University of Texas at Austin, Austin, TX 78712, USA
| | - Kira S Makarova
- National Center for Biotechnology Information, National Library of Medicine, NIH, Bethesda, MD 20894, USA
| | - Laura M Markham
- Institute for Cellular and Molecular Biology and Department of Molecular Biosciences, University of Texas at Austin, Austin, TX 78712, USA
| | - Jun Yao
- Institute for Cellular and Molecular Biology and Department of Molecular Biosciences, University of Texas at Austin, Austin, TX 78712, USA
| | - Patricia Lucas-Elío
- Department of Genetics and Microbiology, Universidad de Murcia, Murcia 30100, Spain
| | - Antonio Sanchez-Amat
- Department of Genetics and Microbiology, Universidad de Murcia, Murcia 30100, Spain
| | - Andrew Z Fire
- Department of Pathology, Stanford University, Stanford, CA 94305, USA
| | - Eugene V Koonin
- National Center for Biotechnology Information, National Library of Medicine, NIH, Bethesda, MD 20894, USA
| | - Alan M Lambowitz
- Institute for Cellular and Molecular Biology and Department of Molecular Biosciences, University of Texas at Austin, Austin, TX 78712, USA.
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45
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Shivram H, Iyer VR. Identification and removal of sequencing artifacts produced by mispriming during reverse transcription in multiple RNA-seq technologies. RNA (NEW YORK, N.Y.) 2018; 24:1266-1274. [PMID: 29950518 PMCID: PMC6097653 DOI: 10.1261/rna.066217.118] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/23/2018] [Accepted: 06/26/2018] [Indexed: 06/08/2023]
Abstract
The quality of RNA sequencing data relies on specific priming by the primer used for reverse transcription (RT-primer). Nonspecific annealing of the RT-primer to the RNA template can generate reads with incorrect cDNA ends and can cause misinterpretation of data (RT mispriming). This kind of artifact in RNA-seq based technologies is underappreciated and currently no adequate tools exist to computationally remove them from published data sets. We show that mispriming can occur with as little as two bases of complementarity at the 3' end of the primer followed by intermittent regions of complementarity. We also provide a computational pipeline that identifies cDNA reads produced from RT mispriming, allowing users to filter them out from any aligned data set. Using this analysis pipeline, we identify thousands of mispriming events in a dozen published data sets from diverse technologies including short RNA-seq, total/mRNA-seq, HITS-CLIP, and GRO-seq. We further show how RT mispriming can lead to misinterpretation of data. In addition to providing a solution to computationally remove RT-misprimed reads, we also propose an experimental solution to completely avoid RT-mispriming by performing RNA-seq using thermostable group II intron derived reverse transcriptase (TGIRT-seq).
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Affiliation(s)
- Haridha Shivram
- Center for Systems and Synthetic Biology, Institute for Cellular and Molecular Biology, Department of Molecular Biosciences, University of Texas at Austin, Austin, Texas 78712, USA
| | - Vishwanath R Iyer
- Center for Systems and Synthetic Biology, Institute for Cellular and Molecular Biology, Department of Molecular Biosciences, University of Texas at Austin, Austin, Texas 78712, USA
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46
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Wu DC, Yao J, Ho KS, Lambowitz AM, Wilke CO. Limitations of alignment-free tools in total RNA-seq quantification. BMC Genomics 2018; 19:510. [PMID: 29969991 PMCID: PMC6042521 DOI: 10.1186/s12864-018-4869-5] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2018] [Accepted: 06/14/2018] [Indexed: 11/11/2022] Open
Abstract
Background Alignment-free RNA quantification tools have significantly increased the speed of RNA-seq analysis. However, it is unclear whether these state-of-the-art RNA-seq analysis pipelines can quantify small RNAs as accurately as they do with long RNAs in the context of total RNA quantification. Result We comprehensively tested and compared four RNA-seq pipelines for accuracy of gene quantification and fold-change estimation. We used a novel total RNA benchmarking dataset in which small non-coding RNAs are highly represented along with other long RNAs. The four RNA-seq pipelines consisted of two commonly-used alignment-free pipelines and two variants of alignment-based pipelines. We found that all pipelines showed high accuracy for quantifying the expression of long and highly-abundant genes. However, alignment-free pipelines showed systematically poorer performance in quantifying lowly-abundant and small RNAs. Conclusion We have shown that alignment-free and traditional alignment-based quantification methods perform similarly for common gene targets, such as protein-coding genes. However, we have identified a potential pitfall in analyzing and quantifying lowly-expressed genes and small RNAs with alignment-free pipelines, especially when these small RNAs contain biological variations. Electronic supplementary material The online version of this article (10.1186/s12864-018-4869-5) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Douglas C Wu
- Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin, 78712, TX, USA.,Department of Molecular Biosciences, The University of Texas at Austin, Austin, 78712, TX, USA
| | - Jun Yao
- Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin, 78712, TX, USA.,Department of Molecular Biosciences, The University of Texas at Austin, Austin, 78712, TX, USA
| | - Kevin S Ho
- Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin, 78712, TX, USA.,Department of Molecular Biosciences, The University of Texas at Austin, Austin, 78712, TX, USA
| | - Alan M Lambowitz
- Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin, 78712, TX, USA.,Department of Molecular Biosciences, The University of Texas at Austin, Austin, 78712, TX, USA
| | - Claus O Wilke
- Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin, 78712, TX, USA. .,Department of Integrative Biology, The University of Texas at Austin, Austin, 78712, TX, USA.
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47
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Boivin V, Deschamps-Francoeur G, Couture S, Nottingham RM, Bouchard-Bourelle P, Lambowitz AM, Scott MS, Abou-Elela S. Simultaneous sequencing of coding and noncoding RNA reveals a human transcriptome dominated by a small number of highly expressed noncoding genes. RNA (NEW YORK, N.Y.) 2018; 24:950-965. [PMID: 29703781 PMCID: PMC6004057 DOI: 10.1261/rna.064493.117] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/16/2017] [Accepted: 04/24/2018] [Indexed: 06/01/2023]
Abstract
Comparing the abundance of one RNA molecule to another is crucial for understanding cellular functions but most sequencing techniques can target only specific subsets of RNA. In this study, we used a new fragmented ribodepleted TGIRT sequencing method that uses a thermostable group II intron reverse transcriptase (TGIRT) to generate a portrait of the human transcriptome depicting the quantitative relationship of all classes of nonribosomal RNA longer than 60 nt. Comparison between different sequencing methods indicated that FRT is more accurate in ranking both mRNA and noncoding RNA than viral reverse transcriptase-based sequencing methods, even those that specifically target these species. Measurements of RNA abundance in different cell lines using this method correlate with biochemical estimates, confirming tRNA as the most abundant nonribosomal RNA biotype. However, the single most abundant transcript is 7SL RNA, a component of the signal recognition particle. Structured noncoding RNAs (sncRNAs) associated with the same biological process are expressed at similar levels, with the exception of RNAs with multiple functions like U1 snRNA. In general, sncRNAs forming RNPs are hundreds to thousands of times more abundant than their mRNA counterparts. Surprisingly, only 50 sncRNA genes produce half of the non-rRNA transcripts detected in two different cell lines. Together the results indicate that the human transcriptome is dominated by a small number of highly expressed sncRNAs specializing in functions related to translation and splicing.
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Affiliation(s)
- Vincent Boivin
- Département de biochimie, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, Québec J1E 4K8, Canada
| | - Gabrielle Deschamps-Francoeur
- Département de biochimie, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, Québec J1E 4K8, Canada
| | - Sonia Couture
- Département de microbiologie et d'infectiologie, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, Québec J1E 4K8, Canada
| | - Ryan M Nottingham
- Institute for Cellular and Molecular Biology and Department of Molecular Biosciences, University of Texas at Austin, Austin, Texas 78712, USA
| | - Philia Bouchard-Bourelle
- Département de biochimie, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, Québec J1E 4K8, Canada
| | - Alan M Lambowitz
- Institute for Cellular and Molecular Biology and Department of Molecular Biosciences, University of Texas at Austin, Austin, Texas 78712, USA
| | - Michelle S Scott
- Département de biochimie, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, Québec J1E 4K8, Canada
| | - Sherif Abou-Elela
- Département de microbiologie et d'infectiologie, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, Québec J1E 4K8, Canada
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Mohr G, Kang SYS, Park SK, Qin Y, Grohman J, Yao J, Stamos JL, Lambowitz AM. A Highly Proliferative Group IIC Intron from Geobacillus stearothermophilus Reveals New Features of Group II Intron Mobility and Splicing. J Mol Biol 2018; 430:2760-2783. [PMID: 29913158 DOI: 10.1016/j.jmb.2018.06.019] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2018] [Revised: 05/01/2018] [Accepted: 06/05/2018] [Indexed: 12/13/2022]
Abstract
The thermostable Geobacillus stearothermophilus GsI-IIC intron is among the few bacterial group II introns found to proliferate to high copy number in its host genome. Here, we developed a bacterial genetic assay for retrohoming and biochemical assays for protein-dependent and self-splicing of GsI-IIC. We found that GsI-IIC, like other group IIC introns, retrohomes into sites having a 5'-exon DNA hairpin, typically from a bacterial transcription terminator, followed by short intron-binding sequences (IBSs) recognized by base pairing of exon-binding sequences (EBSs) in the intron RNA. Intron RNA insertion occurs preferentially but not exclusively into the parental lagging strand at DNA replication forks, using a nascent lagging strand DNA as a primer for reverse transcription. In vivo mobility assays, selections, and mutagenesis indicated that a variety of GC-rich DNA hairpins of 7-19 bp with continuous base pairs or internal elbow regions support efficient intron mobility and identified a critically recognized nucleotide (T-5) between the hairpin and IBS1, a feature not reported previously for group IIC introns. Neither the hairpin nor T-5 is required for intron excision or lariat formation during RNA splicing, but the 5'-exon sequence can affect the efficiency of exon ligation. Structural modeling suggests that the 5'-exon DNA hairpin and T-5 bind to the thumb and DNA-binding domains of GsI-IIC reverse transcriptase. This mode of DNA target site recognition enables the intron to proliferate to high copy number by recognizing numerous transcription terminators and then finding the best match for the EBS/IBS interactions within a short distance downstream.
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Affiliation(s)
- Georg Mohr
- Institute for Cellular and Molecular Biology, University of Texas at Austin, Austin, TX 78712, USA; Department of Molecular Biosciences, University of Texas at Austin, Austin, TX 78712, USA
| | - Sean Yoon-Seo Kang
- Institute for Cellular and Molecular Biology, University of Texas at Austin, Austin, TX 78712, USA; Department of Molecular Biosciences, University of Texas at Austin, Austin, TX 78712, USA
| | - Seung Kuk Park
- Institute for Cellular and Molecular Biology, University of Texas at Austin, Austin, TX 78712, USA; Department of Molecular Biosciences, University of Texas at Austin, Austin, TX 78712, USA
| | - Yidan Qin
- Institute for Cellular and Molecular Biology, University of Texas at Austin, Austin, TX 78712, USA; Department of Molecular Biosciences, University of Texas at Austin, Austin, TX 78712, USA
| | - Jacob Grohman
- Institute for Cellular and Molecular Biology, University of Texas at Austin, Austin, TX 78712, USA; Department of Molecular Biosciences, University of Texas at Austin, Austin, TX 78712, USA
| | - Jun Yao
- Institute for Cellular and Molecular Biology, University of Texas at Austin, Austin, TX 78712, USA; Department of Molecular Biosciences, University of Texas at Austin, Austin, TX 78712, USA
| | - Jennifer L Stamos
- Institute for Cellular and Molecular Biology, University of Texas at Austin, Austin, TX 78712, USA; Department of Molecular Biosciences, University of Texas at Austin, Austin, TX 78712, USA
| | - Alan M Lambowitz
- Institute for Cellular and Molecular Biology, University of Texas at Austin, Austin, TX 78712, USA; Department of Molecular Biosciences, University of Texas at Austin, Austin, TX 78712, USA.
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49
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Stojković V, Chu T, Therizols G, Weinberg DE, Fujimori DG. miCLIP-MaPseq, a Substrate Identification Approach for Radical SAM RNA Methylating Enzymes. J Am Chem Soc 2018; 140:7135-7143. [PMID: 29782154 DOI: 10.1021/jacs.8b02618] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Although present across bacteria, the large family of radical SAM RNA methylating enzymes is largely uncharacterized. Escherichia coli RlmN, the founding member of the family, methylates an adenosine in 23S rRNA and several tRNAs to yield 2-methyladenosine (m2A). However, varied RNA substrate specificity among RlmN enzymes, combined with the ability of certain family members to generate 8-methyladenosine (m8A), makes functional predictions across this family challenging. Here, we present a method for unbiased substrate identification that exploits highly efficient, mechanism-based cross-linking between the enzyme and its RNA substrates. Additionally, by determining that the thermostable group II intron reverse transcriptase introduces mismatches at the site of the cross-link, we have identified the precise positions of RNA modification using mismatch profiling. These results illustrate the capability of our method to define enzyme-substrate pairs and determine modification sites of the largely uncharacterized radical SAM RNA methylating enzyme family.
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Affiliation(s)
- Vanja Stojković
- Department of Cellular and Molecular Pharmacology , University of California , San Francisco , California 94158 , United States
| | - Tongyue Chu
- Department of Cellular and Molecular Pharmacology , University of California , San Francisco , California 94158 , United States
| | - Gabriel Therizols
- Department of Cellular and Molecular Pharmacology , University of California , San Francisco , California 94158 , United States
| | - David E Weinberg
- Department of Cellular and Molecular Pharmacology , University of California , San Francisco , California 94158 , United States
| | - Danica Galonić Fujimori
- Department of Cellular and Molecular Pharmacology , University of California , San Francisco , California 94158 , United States.,Department of Pharmaceutical Chemistry , University of California , 600 16th Street, MC2280 San Francisco , California 94158 , United States
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50
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Boone M, De Koker A, Callewaert N. Capturing the 'ome': the expanding molecular toolbox for RNA and DNA library construction. Nucleic Acids Res 2018; 46:2701-2721. [PMID: 29514322 PMCID: PMC5888575 DOI: 10.1093/nar/gky167] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2017] [Revised: 02/05/2018] [Accepted: 02/23/2018] [Indexed: 12/14/2022] Open
Abstract
All sequencing experiments and most functional genomics screens rely on the generation of libraries to comprehensively capture pools of targeted sequences. In the past decade especially, driven by the progress in the field of massively parallel sequencing, numerous studies have comprehensively assessed the impact of particular manipulations on library complexity and quality, and characterized the activities and specificities of several key enzymes used in library construction. Fortunately, careful protocol design and reagent choice can substantially mitigate many of these biases, and enable reliable representation of sequences in libraries. This review aims to guide the reader through the vast expanse of literature on the subject to promote informed library generation, independent of the application.
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Affiliation(s)
- Morgane Boone
- Center for Medical Biotechnology, VIB, Zwijnaarde 9052, Belgium
- Department of Biochemistry and Microbiology, Ghent University, Ghent 9000, Belgium
| | - Andries De Koker
- Center for Medical Biotechnology, VIB, Zwijnaarde 9052, Belgium
- Department of Biochemistry and Microbiology, Ghent University, Ghent 9000, Belgium
| | - Nico Callewaert
- Center for Medical Biotechnology, VIB, Zwijnaarde 9052, Belgium
- Department of Biochemistry and Microbiology, Ghent University, Ghent 9000, Belgium
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