1
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Nemsick S, Hansen AS. Molecular models of bidirectional promoter regulation. Curr Opin Struct Biol 2024; 87:102865. [PMID: 38905929 DOI: 10.1016/j.sbi.2024.102865] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2023] [Revised: 03/30/2024] [Accepted: 05/27/2024] [Indexed: 06/23/2024]
Abstract
Approximately 11% of human genes are transcribed by a bidirectional promoter (BDP), defined as two genes with <1 kb between their transcription start sites. Despite their evolutionary conservation and enrichment for housekeeping genes and oncogenes, the regulatory role of BDPs remains unclear. BDPs have been suggested to facilitate gene coregulation and/or decrease expression noise. This review discusses these potential regulatory functions through the context of six prospective underlying mechanistic models: a single nucleosome free region, shared transcription factor/regulator binding, cooperative negative supercoiling, bimodal histone marks, joint activation by enhancer(s), and RNA-mediated recruitment of regulators. These molecular mechanisms may act independently and/or cooperatively to facilitate the coregulation and/or decreased expression noise predicted of BDPs.
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Affiliation(s)
- Sarah Nemsick
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; The Gene Regulation Observatory, Broad Institute of MIT and Harvard, Cambridge, MA 02139, USA; Koch Institute for Integrative Cancer Research, Cambridge, MA 02139, USA
| | - Anders S Hansen
- Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; The Gene Regulation Observatory, Broad Institute of MIT and Harvard, Cambridge, MA 02139, USA; Koch Institute for Integrative Cancer Research, Cambridge, MA 02139, USA.
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2
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McShane A, Narayanan IV, Paulsen MT, Ashaka M, Blinkiewicz H, Yang NT, Magnuson B, Bedi K, Wilson TE, Ljungman M. Characterizing nascent transcription patterns of PROMPTs, eRNAs, and readthrough transcripts in the ENCODE4 deeply profiled cell lines. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.04.09.588612. [PMID: 38645116 PMCID: PMC11030308 DOI: 10.1101/2024.04.09.588612] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/23/2024]
Abstract
Arising as co-products of canonical gene expression, transcription-associated lincRNAs, such as promoter upstream transcripts (PROMPTs), enhancer RNAs (eRNAs), and readthrough (RT) transcripts, are often regarded as byproducts of transcription, although they may be important for the expression of nearby genes. We identified regions of nascent expression of these lincRNA in 16 human cell lines using Bru-seq techniques, and found distinctly regulated patterns of PROMPT, eRNA, and RT transcription using the diverse biochemical approaches in the ENCODE4 deeply profiled cell lines collection. Transcription of these lincRNAs was influenced by sequence-specific features and the local or 3D chromatin landscape. However, these sequence and chromatin features do not describe the full spectrum of lincRNA expression variability we identify, highlighting the complexity of their regulation. This may suggest that transcription-associated lincRNAs are not merely byproducts, but rather that the transcript itself, or the act of its transcription, is important for genomic function.
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3
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Archuleta SR, Goodrich JA, Kugel JF. Mechanisms and Functions of the RNA Polymerase II General Transcription Machinery during the Transcription Cycle. Biomolecules 2024; 14:176. [PMID: 38397413 PMCID: PMC10886972 DOI: 10.3390/biom14020176] [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: 12/21/2023] [Revised: 01/29/2024] [Accepted: 01/30/2024] [Indexed: 02/25/2024] Open
Abstract
Central to the development and survival of all organisms is the regulation of gene expression, which begins with the process of transcription catalyzed by RNA polymerases. During transcription of protein-coding genes, the general transcription factors (GTFs) work alongside RNA polymerase II (Pol II) to assemble the preinitiation complex at the transcription start site, open the promoter DNA, initiate synthesis of the nascent messenger RNA, transition to productive elongation, and ultimately terminate transcription. Through these different stages of transcription, Pol II is dynamically phosphorylated at the C-terminal tail of its largest subunit, serving as a control mechanism for Pol II elongation and a signaling/binding platform for co-transcriptional factors. The large number of core protein factors participating in the fundamental steps of transcription add dense layers of regulation that contribute to the complexity of temporal and spatial control of gene expression within any given cell type. The Pol II transcription system is highly conserved across different levels of eukaryotes; however, most of the information here will focus on the human Pol II system. This review walks through various stages of transcription, from preinitiation complex assembly to termination, highlighting the functions and mechanisms of the core machinery that participates in each stage.
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Affiliation(s)
| | - James A. Goodrich
- Department of Biochemistry, University of Colorado Boulder, 596 UCB, Boulder, CO 80309, USA;
| | - Jennifer F. Kugel
- Department of Biochemistry, University of Colorado Boulder, 596 UCB, Boulder, CO 80309, USA;
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4
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Arce AL, Mencia R, Cambiagno DA, Lang PL, Liu C, Burbano HA, Weigel D, Manavella PA. Polymorphic inverted repeats near coding genes impact chromatin topology and phenotypic traits in Arabidopsis thaliana. Cell Rep 2023; 42:112029. [PMID: 36689329 DOI: 10.1016/j.celrep.2023.112029] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Revised: 11/03/2022] [Accepted: 01/10/2023] [Indexed: 01/23/2023] Open
Abstract
Transposons are mobile elements that are commonly silenced to protect eukaryotic genome integrity. In plants, transposable element (TE)-derived inverted repeats (IRs) are commonly found near genes, where they affect host gene expression. However, the molecular mechanisms of such regulation are unclear in most cases. Expression of these IRs is associated with production of 24-nt small RNAs, methylation of the IRs, and drastic changes in local 3D chromatin organization. Notably, many of these IRs differ between Arabidopsis thaliana accessions, causing variation in short-range chromatin interactions and gene expression. CRISPR-Cas9-mediated disruption of two IRs leads to a switch in genome topology and gene expression with phenotypic consequences. Our data show that insertion of an IR near a gene provides an anchor point for chromatin interactions that profoundly impact the activity of neighboring loci. This turns IRs into powerful evolutionary agents that can contribute to rapid adaptation.
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Affiliation(s)
- Agustín L Arce
- Instituto de Agrobiotecnología del Litoral (CONICET-UNL), Cátedra de Biología Celular y Molecular, Facultad de Bioquímica y Ciencias Biológicas, Universidad Nacional del Litoral, 3000 Santa Fe, Argentina
| | - Regina Mencia
- Instituto de Agrobiotecnología del Litoral (CONICET-UNL), Cátedra de Biología Celular y Molecular, Facultad de Bioquímica y Ciencias Biológicas, Universidad Nacional del Litoral, 3000 Santa Fe, Argentina
| | - Damian A Cambiagno
- Instituto de Agrobiotecnología del Litoral (CONICET-UNL), Cátedra de Biología Celular y Molecular, Facultad de Bioquímica y Ciencias Biológicas, Universidad Nacional del Litoral, 3000 Santa Fe, Argentina
| | - Patricia L Lang
- Department of Molecular Biology, Max Planck Institute for Biology Tübingen, 72076 Tübingen, Germany
| | - Chang Liu
- Department of Epigenetics, Institute of Biology, University of Hohenheim, Garbenstraße 30, 70599 Stuttgart, Germany
| | - Hernán A Burbano
- Department of Molecular Biology, Max Planck Institute for Biology Tübingen, 72076 Tübingen, Germany; Centre for Life's Origins and Evolution, University College London, London, UK
| | - Detlef Weigel
- Department of Molecular Biology, Max Planck Institute for Biology Tübingen, 72076 Tübingen, Germany
| | - Pablo A Manavella
- Instituto de Agrobiotecnología del Litoral (CONICET-UNL), Cátedra de Biología Celular y Molecular, Facultad de Bioquímica y Ciencias Biológicas, Universidad Nacional del Litoral, 3000 Santa Fe, Argentina.
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5
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Cortazar MA, Erickson B, Fong N, Pradhan SJ, Ntini E, Bentley DL. Xrn2 substrate mapping identifies torpedo loading sites and extensive premature termination of RNA pol II transcription. Genes Dev 2022; 36:1062-1078. [PMID: 36396340 PMCID: PMC9744234 DOI: 10.1101/gad.350004.122] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2022] [Accepted: 10/31/2022] [Indexed: 11/19/2022]
Abstract
The exonuclease torpedo Xrn2 loads onto nascent RNA 5'-PO4 ends and chases down pol II to promote termination downstream from polyA sites. We report that Xrn2 is recruited to preinitiation complexes and "travels" to 3' ends of genes. Mapping of 5'-PO4 ends in nascent RNA identified Xrn2 loading sites stabilized by an active site mutant, Xrn2(D235A). Xrn2 loading sites are approximately two to 20 bases downstream from where CPSF73 cleaves at polyA sites and histone 3' ends. We propose that processing of all mRNA 3' ends comprises cleavage and limited 5'-3' trimming by CPSF73, followed by handoff to Xrn2. A similar handoff occurs at tRNA 3' ends, where cotranscriptional RNase Z cleavage generates novel Xrn2 substrates. Exonuclease-dead Xrn2 increased transcription in 3' flanking regions by inhibiting polyA site-dependent termination. Surprisingly, the mutant Xrn2 also rescued transcription in promoter-proximal regions to the same extent as in 3' flanking regions. eNET-seq revealed Xrn2-mediated degradation of sense and antisense nascent RNA within a few bases of the TSS, where 5'-PO4 ends may be generated by decapping or endonucleolytic cleavage. These results suggest that a major fraction of pol II complexes terminates prematurely close to the start site under normal conditions by an Xrn2-mediated torpedo mechanism.
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Affiliation(s)
- Michael A. Cortazar
- Department of Biochemistry and Molecular Genetics, RNA Bioscience Initiative, University of Colorado School of Medicine, Aurora, Colorado 80045, USA
| | - Benjamin Erickson
- Department of Biochemistry and Molecular Genetics, RNA Bioscience Initiative, University of Colorado School of Medicine, Aurora, Colorado 80045, USA
| | - Nova Fong
- Department of Biochemistry and Molecular Genetics, RNA Bioscience Initiative, University of Colorado School of Medicine, Aurora, Colorado 80045, USA
| | - Sarala J. Pradhan
- Department of Biochemistry and Molecular Genetics, RNA Bioscience Initiative, University of Colorado School of Medicine, Aurora, Colorado 80045, USA
| | - Evgenia Ntini
- Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology–Hellas (FORTH), Heraklion GR-70013, Greece
| | - David L. Bentley
- Department of Biochemistry and Molecular Genetics, RNA Bioscience Initiative, University of Colorado School of Medicine, Aurora, Colorado 80045, USA
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6
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Terrone S, Valat J, Fontrodona N, Giraud G, Claude JB, Combe E, Lapendry A, Polvèche H, Ameur LB, Duvermy A, Modolo L, Bernard P, Mortreux F, Auboeuf D, Bourgeois C. RNA helicase-dependent gene looping impacts messenger RNA processing. Nucleic Acids Res 2022; 50:9226-9246. [PMID: 36039747 PMCID: PMC9458439 DOI: 10.1093/nar/gkac717] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2021] [Revised: 07/25/2022] [Accepted: 08/25/2022] [Indexed: 12/24/2022] Open
Abstract
DDX5 and DDX17 are DEAD-box RNA helicase paralogs which regulate several aspects of gene expression, especially transcription and splicing, through incompletely understood mechanisms. A transcriptome analysis of DDX5/DDX17-depleted human cells confirmed the large impact of these RNA helicases on splicing and revealed a widespread deregulation of 3' end processing. In silico analyses and experiments in cultured cells showed the binding and functional contribution of the genome organizing factor CTCF to chromatin sites at or near a subset of DDX5/DDX17-dependent exons that are characterized by a high GC content and a high density of RNA Polymerase II. We propose the existence of an RNA helicase-dependent relationship between CTCF and the dynamics of transcription across DNA and/or RNA structured regions, that contributes to the processing of internal and terminal exons. Moreover, local DDX5/DDX17-dependent chromatin loops spatially connect RNA helicase-regulated exons with their cognate promoter, and we provide the first direct evidence that de novo gene looping modifies alternative splicing and polyadenylation. Overall our findings uncover the impact of DDX5/DDX17-dependent chromatin folding on pre-messenger RNA processing.
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Affiliation(s)
| | | | - Nicolas Fontrodona
- Laboratoire de Biologie et Modelisation de la Cellule, Ecole Normale Superieure de Lyon, CNRS, UMR 5239, Inserm, U1293, Universite Claude Bernard Lyon 1, 46 allee d'Italie, F-69364 Lyon, France
| | | | - Jean-Baptiste Claude
- Laboratoire de Biologie et Modelisation de la Cellule, Ecole Normale Superieure de Lyon, CNRS, UMR 5239, Inserm, U1293, Universite Claude Bernard Lyon 1, 46 allee d'Italie, F-69364 Lyon, France
| | | | - Audrey Lapendry
- Laboratoire de Biologie et Modelisation de la Cellule, Ecole Normale Superieure de Lyon, CNRS, UMR 5239, Inserm, U1293, Universite Claude Bernard Lyon 1, 46 allee d'Italie, F-69364 Lyon, France
| | - Hélène Polvèche
- Laboratoire de Biologie et Modelisation de la Cellule, Ecole Normale Superieure de Lyon, CNRS, UMR 5239, Inserm, U1293, Universite Claude Bernard Lyon 1, 46 allee d'Italie, F-69364 Lyon, France,CECS/AFM, I-STEM, 28 rue Henri Desbruères, F-91100, Corbeil-Essonnes, France
| | - Lamya Ben Ameur
- Laboratoire de Biologie et Modelisation de la Cellule, Ecole Normale Superieure de Lyon, CNRS, UMR 5239, Inserm, U1293, Universite Claude Bernard Lyon 1, 46 allee d'Italie, F-69364 Lyon, France
| | - Arnaud Duvermy
- Laboratoire de Biologie et Modelisation de la Cellule, Ecole Normale Superieure de Lyon, CNRS, UMR 5239, Inserm, U1293, Universite Claude Bernard Lyon 1, 46 allee d'Italie, F-69364 Lyon, France
| | - Laurent Modolo
- Laboratoire de Biologie et Modelisation de la Cellule, Ecole Normale Superieure de Lyon, CNRS, UMR 5239, Inserm, U1293, Universite Claude Bernard Lyon 1, 46 allee d'Italie, F-69364 Lyon, France
| | - Pascal Bernard
- Laboratoire de Biologie et Modelisation de la Cellule, Ecole Normale Superieure de Lyon, CNRS, UMR 5239, Inserm, U1293, Universite Claude Bernard Lyon 1, 46 allee d'Italie, F-69364 Lyon, France
| | - Franck Mortreux
- Laboratoire de Biologie et Modelisation de la Cellule, Ecole Normale Superieure de Lyon, CNRS, UMR 5239, Inserm, U1293, Universite Claude Bernard Lyon 1, 46 allee d'Italie, F-69364 Lyon, France
| | - Didier Auboeuf
- Laboratoire de Biologie et Modelisation de la Cellule, Ecole Normale Superieure de Lyon, CNRS, UMR 5239, Inserm, U1293, Universite Claude Bernard Lyon 1, 46 allee d'Italie, F-69364 Lyon, France
| | - Cyril F Bourgeois
- To whom correspondence should be addressed. Tel: +33 47272 8663; Fax: +33 47272 8674;
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7
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O'Brien MJ, Ansari A. Critical Involvement of TFIIB in Viral Pathogenesis. Front Mol Biosci 2021; 8:669044. [PMID: 33996913 PMCID: PMC8119876 DOI: 10.3389/fmolb.2021.669044] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Accepted: 04/08/2021] [Indexed: 11/23/2022] Open
Abstract
Viral infections and the harm they cause to their host are a perpetual threat to living organisms. Pathogenesis and subsequent spread of infection requires replication of the viral genome and expression of structural and non-structural proteins of the virus. Generally, viruses use transcription and translation machinery of the host cell to achieve this objective. The viral genome encodes transcriptional regulators that alter the expression of viral and host genes by manipulating initiation and termination steps of transcription. The regulation of the initiation step is often through interactions of viral factors with gene specific factors as well as general transcription factors (GTFs). Among the GTFs, TFIIB (Transcription Factor IIB) is a frequent target during viral pathogenesis. TFIIB is utilized by a plethora of viruses including human immunodeficiency virus, herpes simplex virus, vaccinia virus, Thogoto virus, hepatitis virus, Epstein-Barr virus and gammaherpesviruses to alter gene expression. A number of viral transcriptional regulators exhibit a direct interaction with host TFIIB in order to accomplish expression of their genes and to repress host transcription. Some viruses have evolved proteins with a three-dimensional structure very similar to TFIIB, demonstrating the importance of TFIIB for viral persistence. Upon viral infection, host transcription is selectively altered with viral transcription benefitting. The nature of viral utilization of TFIIB for expression of its own genes, along with selective repression of host antiviral genes and downregulation of general host transcription, makes TFIIB a potential candidate for antiviral therapies.
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Affiliation(s)
- Michael J O'Brien
- Department of Biological Science, Wayne State University, Detroit, MI, United States
| | - Athar Ansari
- Department of Biological Science, Wayne State University, Detroit, MI, United States
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8
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Borg M, Papareddy RK, Dombey R, Axelsson E, Nodine MD, Twell D, Berger F. Epigenetic reprogramming rewires transcription during the alternation of generations in Arabidopsis. eLife 2021; 10:e61894. [PMID: 33491647 PMCID: PMC7920552 DOI: 10.7554/elife.61894] [Citation(s) in RCA: 47] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Accepted: 01/25/2021] [Indexed: 12/18/2022] Open
Abstract
Alternation between morphologically distinct haploid and diploid life forms is a defining feature of most plant and algal life cycles, yet the underlying molecular mechanisms that govern these transitions remain unclear. Here, we explore the dynamic relationship between chromatin accessibility and epigenetic modifications during life form transitions in Arabidopsis. The diploid-to-haploid life form transition is governed by the loss of H3K9me2 and DNA demethylation of transposon-associated cis-regulatory elements. This event is associated with dramatic changes in chromatin accessibility and transcriptional reprogramming. In contrast, the global loss of H3K27me3 in the haploid form shapes a chromatin accessibility landscape that is poised to re-initiate the transition back to diploid life after fertilisation. Hence, distinct epigenetic reprogramming events rewire transcription through major reorganisation of the regulatory epigenome to guide the alternation of generations in flowering plants.
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Affiliation(s)
- Michael Borg
- Gregor Mendel Institute (GMI), Austrian Academy of SciencesViennaAustria
| | | | - Rodolphe Dombey
- Gregor Mendel Institute (GMI), Austrian Academy of SciencesViennaAustria
| | - Elin Axelsson
- Gregor Mendel Institute (GMI), Austrian Academy of SciencesViennaAustria
| | - Michael D Nodine
- Gregor Mendel Institute (GMI), Austrian Academy of SciencesViennaAustria
| | - David Twell
- Gregor Mendel Institute (GMI), Austrian Academy of SciencesViennaAustria
- Department of Genetics, University of LeicesterLeicesterUnited Kingdom
| | - Frédéric Berger
- Gregor Mendel Institute (GMI), Austrian Academy of SciencesViennaAustria
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9
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Al-Husini N, Medler S, Ansari A. Crosstalk of promoter and terminator during RNA polymerase II transcription cycle. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2020; 1863:194657. [PMID: 33246184 DOI: 10.1016/j.bbagrm.2020.194657] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Revised: 11/16/2020] [Accepted: 11/17/2020] [Indexed: 12/16/2022]
Abstract
The transcription cycle of RNAPII is comprised of three consecutive steps; initiation, elongation and termination. It has been assumed that the initiation and termination steps occur in spatial isolation, essentially as independent events. A growing body of evidence, however, has challenged this dogma. First, factors involved in initiation and termination exhibit both a genetic and a physical interaction during transcription. Second, the initiation and termination factors have been found to occupy both ends of a transcribing gene. Third, physical interaction of initiation and termination factors occupying distal ends of a gene sometime results in the entire terminator region of a genes looping back and contact its cognate promoter, thereby forming a looped gene architecture during transcription. A logical interpretation of these findings is that the initiation and termination steps of transcription do not occur in isolation. There is extensive communication of factors occupying promoter and terminator ends of a gene during transcription cycle. This review entails a discussion of the promoter-terminator crosstalk and its implication in the context of transcription.
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Affiliation(s)
- Nadra Al-Husini
- Department of Biological Science, Wayne State University, Detroit, MI, United States of America
| | - Scott Medler
- Department of Biological Science, Wayne State University, Detroit, MI, United States of America
| | - Athar Ansari
- Department of Biological Science, Wayne State University, Detroit, MI, United States of America.
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10
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Chen L, Zhu QH, Kaufmann K. Long non-coding RNAs in plants: emerging modulators of gene activity in development and stress responses. PLANTA 2020; 252:92. [PMID: 33099688 PMCID: PMC7585572 DOI: 10.1007/s00425-020-03480-5] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2020] [Accepted: 09/22/2020] [Indexed: 05/14/2023]
Abstract
MAIN CONCLUSION Long non-coding RNAs modulate gene activity in plant development and stress responses by various molecular mechanisms. Long non-coding RNAs (lncRNAs) are transcripts larger than 200 nucleotides without protein coding potential. Computational approaches have identified numerous lncRNAs in different plant species. Research in the past decade has unveiled that plant lncRNAs participate in a wide range of biological processes, including regulation of flowering time and morphogenesis of reproductive organs, as well as abiotic and biotic stress responses. LncRNAs execute their functions by interacting with DNA, RNA and protein molecules, and by modulating the expression level of their targets through epigenetic, transcriptional, post-transcriptional or translational regulation. In this review, we summarize characteristics of plant lncRNAs, discuss recent progress on understanding of lncRNA functions, and propose an experimental framework for functional characterization.
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Affiliation(s)
- Li Chen
- Institute for Biology, Plant Cell and Molecular Biology, Humboldt-Universität zu Berlin, 10115, Berlin, Germany
| | - Qian-Hao Zhu
- CSIRO Agriculture and Food, GPO Box 1700, Canberra, ACT, 2601, Australia
| | - Kerstin Kaufmann
- Institute for Biology, Plant Cell and Molecular Biology, Humboldt-Universität zu Berlin, 10115, Berlin, Germany.
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11
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Genetic circuit design automation for yeast. Nat Microbiol 2020; 5:1349-1360. [DOI: 10.1038/s41564-020-0757-2] [Citation(s) in RCA: 58] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Accepted: 06/17/2020] [Indexed: 11/08/2022]
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12
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Yang Y, Song S, Meng Q, Wang L, Li X, Xie S, Chen Y, Jiang X, Wang C, Lu Y, Xin X, Pu H, Gui X, Li T, Xu J, Li J, Jia S, Lu D. miR24-2 accelerates progression of liver cancer cells by activating Pim1 through tri-methylation of Histone H3 on the ninth lysine. J Cell Mol Med 2020; 24:2772-2790. [PMID: 32030886 PMCID: PMC7077597 DOI: 10.1111/jcmm.15030] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2019] [Revised: 11/07/2019] [Accepted: 12/09/2019] [Indexed: 12/16/2022] Open
Abstract
Several microRNAs are associated with carcinogenesis and tumour progression. Herein, our observations suggest both miR24‐2 and Pim1 are up‐regulated in human liver cancers, and miR24‐2 accelerates growth of liver cancer cells in vitro and in vivo. Mechanistically, miR24‐2 increases the expression of N6‐adenosine‐methyltransferase METTL3 and thereafter promotes the expression of miR6079 via RNA methylation modification. Furthermore, miR6079 targets JMJD2A and then increased the tri‐methylation of histone H3 on the ninth lysine (H3K9me3). Therefore, miR24‐2 inhibits JMJD2A by increasing miR6079 and then increases H3K9me3. Strikingly, miR24‐2 increases the expression of Pim1 dependent on H3K9me3 and METTL3. Notably, our findings suggest that miR24‐2 alters several related genes (pHistone H3, SUZ12, SUV39H1, Nanog, MEKK4, pTyr) and accelerates progression of liver cancer cells through Pim1 activation. In particular, Pim1 is required for the oncogenic action of miR24‐2 in liver cancer. This study elucidates a novel mechanism for miR24‐2 in liver cancer and suggests that miR24‐2 may be used as novel therapeutic targets of liver cancer.
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Affiliation(s)
- Yuxin Yang
- Shanghai Putuo District People's Hospital, School of Life Science and Technology, Tongji University, Shanghai, China.,School of Medical Technology, Shanghai University of Medicine and Health Sciences, Shanghai, China
| | - Shuting Song
- Shanghai Putuo District People's Hospital, School of Life Science and Technology, Tongji University, Shanghai, China
| | - Qiuyu Meng
- Shanghai Putuo District People's Hospital, School of Life Science and Technology, Tongji University, Shanghai, China
| | - Liyan Wang
- Shanghai Putuo District People's Hospital, School of Life Science and Technology, Tongji University, Shanghai, China
| | - Xiaonan Li
- Shanghai Putuo District People's Hospital, School of Life Science and Technology, Tongji University, Shanghai, China
| | - Sijie Xie
- Shanghai Putuo District People's Hospital, School of Life Science and Technology, Tongji University, Shanghai, China
| | - Yingjie Chen
- Shanghai Putuo District People's Hospital, School of Life Science and Technology, Tongji University, Shanghai, China
| | - Xiaoxue Jiang
- Shanghai Putuo District People's Hospital, School of Life Science and Technology, Tongji University, Shanghai, China
| | - Chen Wang
- Shanghai Putuo District People's Hospital, School of Life Science and Technology, Tongji University, Shanghai, China
| | - Yanan Lu
- Shanghai Putuo District People's Hospital, School of Life Science and Technology, Tongji University, Shanghai, China
| | - Xiaoru Xin
- Shanghai Putuo District People's Hospital, School of Life Science and Technology, Tongji University, Shanghai, China
| | - Hu Pu
- Shanghai Putuo District People's Hospital, School of Life Science and Technology, Tongji University, Shanghai, China
| | - Xin Gui
- Shanghai Putuo District People's Hospital, School of Life Science and Technology, Tongji University, Shanghai, China
| | - Tianming Li
- Shanghai Putuo District People's Hospital, School of Life Science and Technology, Tongji University, Shanghai, China
| | - Jie Xu
- School of Medicine, Tongji University, Shanghai, China
| | - Jiao Li
- School of Medicine, Tongji University, Shanghai, China
| | - Song Jia
- School of Medicine, Tongji University, Shanghai, China
| | - Dongdong Lu
- Shanghai Putuo District People's Hospital, School of Life Science and Technology, Tongji University, Shanghai, China
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13
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Wang HLV, Chekanova JA. Novel mRNAs 3' end-associated cis-regulatory elements with epigenomic signatures of mammalian enhancers in the Arabidopsis genome. RNA (NEW YORK, N.Y.) 2019; 25:1242-1258. [PMID: 31311821 PMCID: PMC6800480 DOI: 10.1261/rna.071209.119] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Accepted: 07/04/2019] [Indexed: 06/10/2023]
Abstract
The precise spatial and temporal control of gene expression requires the coordinated action of genomic cis-regulatory elements (CREs), including transcriptional enhancers. However, our knowledge of enhancers in plants remains rudimentary and only a few plant enhancers have been experimentally defined. Here, we screened the Arabidopsis thaliana genome and identified >1900 unique candidate CREs that carry the genomic signatures of mammalian enhancers. These were termed putative enhancer-like elements (PEs). Nearly all PEs are intragenic and, unexpectedly, most associate with the 3' ends of protein-coding genes. PEs are hotspots for transcription factor binding and harbor motifs resembling cleavage/polyadenylation signals, potentially coupling 3' end processing to the transcriptional regulation of other genes. Hi-C data showed that 24% of PEs are located at regions that can interact intrachromosomally with other protein-coding genes and, surprisingly, many of these target genes interact with PEs through their 3' UTRs. Examination of the genomes of 1135 sequenced Arabidopsis accessions showed that PEs are conserved. Our findings suggest that the identified PEs may serve as transcriptional enhancers and sites for mRNA 3' end processing, and constitute a novel group of CREs in Arabidopsis.
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Affiliation(s)
- Hsiao-Lin V Wang
- Mycological Research Center, College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, 350002, Fujian, China
| | - Julia A Chekanova
- Mycological Research Center, College of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, 350002, Fujian, China
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14
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Gurumurthy A, Shen Y, Gunn E, Bungert J. Phase Separation and Transcription Regulation: Are Super-Enhancers and Locus Control Regions Primary Sites of Transcription Complex Assembly? Bioessays 2019; 41:e1800164. [PMID: 30500078 PMCID: PMC6484441 DOI: 10.1002/bies.201800164] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2018] [Revised: 10/31/2018] [Indexed: 01/10/2023]
Abstract
It is proposed that the multiple enhancer elements associated with locus control regions and super-enhancers recruit RNA polymerase II and efficiently assemble elongation competent transcription complexes that are transferred to target genes by transcription termination and transient looping mechanisms. It is well established that transcription complexes are recruited not only to promoters but also to enhancers, where they generate enhancer RNAs. Transcription at enhancers is unstable and frequently aborted. Furthermore, the Integrator and WD-domain containing protein 82 mediate transcription termination at enhancers. Abortion and termination of transcription at the multiple enhancers of locus control regions and super-enhancers provide a large pool of elongation competent transcription complexes. These are efficiently captured by strong basal promoter elements at target genes during transient looping interactions.
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Affiliation(s)
- Aishwarya Gurumurthy
- Department of Biochemistry and Molecular Biology, College of Medicine,
UF Health Cancer Center, Genetics Institute, Powell Gene Therapy Center,
University of Florida, Gainesville, Florida, 32610, U.S.A., Phone: 352-273-8098,
Fax: 352-3f92-2953
| | - Yong Shen
- Department of Biochemistry and Molecular Biology, College of Medicine,
UF Health Cancer Center, Genetics Institute, Powell Gene Therapy Center,
University of Florida, Gainesville, Florida, 32610, U.S.A., Phone: 352-273-8098,
Fax: 352-3f92-2953
| | - Eliot Gunn
- Department of Biochemistry and Molecular Biology, College of Medicine,
UF Health Cancer Center, Genetics Institute, Powell Gene Therapy Center,
University of Florida, Gainesville, Florida, 32610, U.S.A., Phone: 352-273-8098,
Fax: 352-3f92-2953
| | - Jörg Bungert
- Department of Biochemistry and Molecular Biology, College of Medicine,
UF Health Cancer Center, Genetics Institute, Powell Gene Therapy Center,
University of Florida, Gainesville, Florida, 32610, U.S.A., Phone: 352-273-8098,
Fax: 352-3f92-2953
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15
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Werner MS, Sieriebriennikov B, Prabh N, Loschko T, Lanz C, Sommer RJ. Young genes have distinct gene structure, epigenetic profiles, and transcriptional regulation. Genome Res 2018; 28:1675-1687. [PMID: 30232198 PMCID: PMC6211652 DOI: 10.1101/gr.234872.118] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2018] [Accepted: 09/05/2018] [Indexed: 12/22/2022]
Abstract
Species-specific, new, or "orphan" genes account for 10%-30% of eukaryotic genomes. Although initially considered to have limited function, an increasing number of orphan genes have been shown to provide important phenotypic innovation. How new genes acquire regulatory sequences for proper temporal and spatial expression is unknown. Orphan gene regulation may rely in part on origination in open chromatin adjacent to preexisting promoters, although this has not yet been assessed by genome-wide analysis of chromatin states. Here, we combine taxon-rich nematode phylogenies with Iso-Seq, RNA-seq, ChIP-seq, and ATAC-seq to identify the gene structure and epigenetic signature of orphan genes in the satellite model nematode Pristionchus pacificus Consistent with previous findings, we find young genes are shorter, contain fewer exons, and are on average less strongly expressed than older genes. However, the subset of orphan genes that are expressed exhibit distinct chromatin states from similarly expressed conserved genes. Orphan gene transcription is determined by a lack of repressive histone modifications, confirming long-held hypotheses that open chromatin is important for new gene formation. Yet orphan gene start sites more closely resemble enhancers defined by H3K4me1, H3K27ac, and ATAC-seq peaks, in contrast to conserved genes that exhibit traditional promoters defined by H3K4me3 and H3K27ac. Although the majority of orphan genes are located on chromosome arms that contain high recombination rates and repressive histone marks, strongly expressed orphan genes are more randomly distributed. Our results support a model of new gene origination by rare integration into open chromatin near enhancers.
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Affiliation(s)
- Michael S Werner
- Department of Evolutionary Biology, Max Planck Institute for Developmental Biology, 72076 Tübingen, Germany
| | - Bogdan Sieriebriennikov
- Department of Evolutionary Biology, Max Planck Institute for Developmental Biology, 72076 Tübingen, Germany
| | - Neel Prabh
- Department of Evolutionary Biology, Max Planck Institute for Developmental Biology, 72076 Tübingen, Germany
| | - Tobias Loschko
- Department of Evolutionary Biology, Max Planck Institute for Developmental Biology, 72076 Tübingen, Germany
| | - Christa Lanz
- Department of Evolutionary Biology, Max Planck Institute for Developmental Biology, 72076 Tübingen, Germany
| | - Ralf J Sommer
- Department of Evolutionary Biology, Max Planck Institute for Developmental Biology, 72076 Tübingen, Germany
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16
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Atkinson SR, Marguerat S, Bitton DA, Rodríguez-López M, Rallis C, Lemay JF, Cotobal C, Malecki M, Smialowski P, Mata J, Korber P, Bachand F, Bähler J. Long noncoding RNA repertoire and targeting by nuclear exosome, cytoplasmic exonuclease, and RNAi in fission yeast. RNA (NEW YORK, N.Y.) 2018; 24:1195-1213. [PMID: 29914874 PMCID: PMC6097657 DOI: 10.1261/rna.065524.118] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/02/2018] [Accepted: 06/14/2018] [Indexed: 05/31/2023]
Abstract
Long noncoding RNAs (lncRNAs), which are longer than 200 nucleotides but often unstable, contribute a substantial and diverse portion to pervasive noncoding transcriptomes. Most lncRNAs are poorly annotated and understood, although several play important roles in gene regulation and diseases. Here we systematically uncover and analyze lncRNAs in Schizosaccharomyces pombe. Based on RNA-seq data from twelve RNA-processing mutants and nine physiological conditions, we identify 5775 novel lncRNAs, nearly 4× the previously annotated lncRNAs. The expression of most lncRNAs becomes strongly induced under the genetic and physiological perturbations, most notably during late meiosis. Most lncRNAs are cryptic and suppressed by three RNA-processing pathways: the nuclear exosome, cytoplasmic exonuclease, and RNAi. Double-mutant analyses reveal substantial coordination and redundancy among these pathways. We classify lncRNAs by their dominant pathway into cryptic unstable transcripts (CUTs), Xrn1-sensitive unstable transcripts (XUTs), and Dicer-sensitive unstable transcripts (DUTs). XUTs and DUTs are enriched for antisense lncRNAs, while CUTs are often bidirectional and actively translated. The cytoplasmic exonuclease, along with RNAi, dampens the expression of thousands of lncRNAs and mRNAs that become induced during meiosis. Antisense lncRNA expression mostly negatively correlates with sense mRNA expression in the physiological, but not the genetic conditions. Intergenic and bidirectional lncRNAs emerge from nucleosome-depleted regions, upstream of positioned nucleosomes. Our results highlight both similarities and differences to lncRNA regulation in budding yeast. This broad survey of the lncRNA repertoire and characteristics in S. pombe, and the interwoven regulatory pathways that target lncRNAs, provides a rich framework for their further functional analyses.
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Affiliation(s)
- Sophie R Atkinson
- Research Department of Genetics, Evolution and Environment and UCL Genetics Institute, University College London, London WC1E 6BT, United Kingdom
| | - Samuel Marguerat
- Research Department of Genetics, Evolution and Environment and UCL Genetics Institute, University College London, London WC1E 6BT, United Kingdom
- MRC London Institute of Medical Sciences (LMS), London W12 0NN, United Kingdom
- Institute of Clinical Sciences (ICS), Faculty of Medicine, Imperial College London, London W12 0NN, United Kingdom
| | - Danny A Bitton
- Research Department of Genetics, Evolution and Environment and UCL Genetics Institute, University College London, London WC1E 6BT, United Kingdom
| | - Maria Rodríguez-López
- Research Department of Genetics, Evolution and Environment and UCL Genetics Institute, University College London, London WC1E 6BT, United Kingdom
| | - Charalampos Rallis
- Research Department of Genetics, Evolution and Environment and UCL Genetics Institute, University College London, London WC1E 6BT, United Kingdom
| | - Jean-François Lemay
- Department of Biochemistry, Sherbrooke, Université de Sherbrooke, Quebec J1H 5N4, Canada
| | - Cristina Cotobal
- Research Department of Genetics, Evolution and Environment and UCL Genetics Institute, University College London, London WC1E 6BT, United Kingdom
| | - Michal Malecki
- Research Department of Genetics, Evolution and Environment and UCL Genetics Institute, University College London, London WC1E 6BT, United Kingdom
| | - Pawel Smialowski
- LMU Munich, Biomedical Center, 82152 Planegg-Martinsried near Munich, Germany
| | - Juan Mata
- Department of Biochemistry, University of Cambridge, Cambridge CB2 1QW, United Kingdom
| | - Philipp Korber
- LMU Munich, Biomedical Center, 82152 Planegg-Martinsried near Munich, Germany
| | - François Bachand
- Department of Biochemistry, Sherbrooke, Université de Sherbrooke, Quebec J1H 5N4, Canada
| | - Jürg Bähler
- Research Department of Genetics, Evolution and Environment and UCL Genetics Institute, University College London, London WC1E 6BT, United Kingdom
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17
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The Role of Long Non-Coding RNAs in Hepatocarcinogenesis. Int J Mol Sci 2018; 19:ijms19030682. [PMID: 29495592 PMCID: PMC5877543 DOI: 10.3390/ijms19030682] [Citation(s) in RCA: 57] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2018] [Revised: 02/23/2018] [Accepted: 02/24/2018] [Indexed: 02/07/2023] Open
Abstract
Whole-transcriptome analyses have revealed that a large proportion of the human genome is transcribed in non-protein-coding transcripts, designated as long non-coding RNAs (lncRNAs). Rather than being “transcriptional noise”, increasing evidence indicates that lncRNAs are key players in the regulation of many biological processes, including transcription, post-translational modification and inhibition and chromatin remodeling. Indeed, lncRNAs are widely dysregulated in human cancers, including hepatocellular carcinoma (HCC). Functional studies are beginning to provide insights into the role of oncogenic and tumor suppressive lncRNAs in the regulation of cell proliferation and motility, as well as oncogenic and metastatic potential in HCC. A better understanding of the molecular mechanisms and the complex network of interactions in which lncRNAs are involved could reveal novel diagnostic and prognostic biomarkers. Crucially, it may provide novel therapeutic opportunities to add to the currently limited number of therapeutic options for HCC patients. In this review, we summarize the current status of the field, with a focus on the best characterized dysregulated lncRNAs in HCC.
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18
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Ne E, Palstra RJ, Mahmoudi T. Transcription: Insights From the HIV-1 Promoter. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2018; 335:191-243. [DOI: 10.1016/bs.ircmb.2017.07.011] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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19
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Daneshvar K, Pondick JV, Kim BM, Zhou C, York SR, Macklin JA, Abualteen A, Tan B, Sigova AA, Marcho C, Tremblay KD, Mager J, Choi MY, Mullen AC. DIGIT Is a Conserved Long Noncoding RNA that Regulates GSC Expression to Control Definitive Endoderm Differentiation of Embryonic Stem Cells. Cell Rep 2017; 17:353-365. [PMID: 27705785 DOI: 10.1016/j.celrep.2016.09.017] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2015] [Revised: 08/12/2016] [Accepted: 09/03/2016] [Indexed: 02/06/2023] Open
Abstract
Long noncoding RNAs (lncRNAs) exhibit diverse functions, including regulation of development. Here, we combine genome-wide mapping of SMAD3 occupancy with expression analysis to identify lncRNAs induced by activin signaling during endoderm differentiation of human embryonic stem cells (hESCs). We find that DIGIT is divergent to Goosecoid (GSC) and expressed during endoderm differentiation. Deletion of the SMAD3-occupied enhancer proximal to DIGIT inhibits DIGIT and GSC expression and definitive endoderm differentiation. Disruption of the gene encoding DIGIT and depletion of the DIGIT transcript reveal that DIGIT is required for definitive endoderm differentiation. In addition, we identify the mouse ortholog of DIGIT and show that it is expressed during development and promotes definitive endoderm differentiation of mouse ESCs. DIGIT regulates GSC in trans, and activation of endogenous GSC expression is sufficient to rescue definitive endoderm differentiation in DIGIT-deficient hESCs. Our study defines DIGIT as a conserved noncoding developmental regulator of definitive endoderm.
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Affiliation(s)
- Kaveh Daneshvar
- Gastrointestinal Unit, Department of Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA
| | - Joshua V Pondick
- Gastrointestinal Unit, Department of Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA
| | - Byeong-Moo Kim
- Gastrointestinal Unit, Department of Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA
| | - Chan Zhou
- Gastrointestinal Unit, Department of Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA
| | - Samuel R York
- Gastrointestinal Unit, Department of Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA
| | - Jillian A Macklin
- Gastrointestinal Unit, Department of Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA
| | - Ameed Abualteen
- Gastrointestinal Unit, Department of Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA; Harvard Stem Cell Institute, Cambridge, MA 02138, USA
| | - Bo Tan
- Gastrointestinal Unit, Department of Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA; School of Fundamental Medical Sciences, Guangzhou University of Chinese Medicine, Guangzhou 510405, China
| | - Alla A Sigova
- Whitehead Institute for Biomedical Research, Cambridge, MA 02142, USA
| | - Chelsea Marcho
- Department of Veterinary and Animal Sciences, University of Massachusetts at Amherst, Amherst, MA 01003, USA
| | - Kimberly D Tremblay
- Department of Veterinary and Animal Sciences, University of Massachusetts at Amherst, Amherst, MA 01003, USA
| | - Jesse Mager
- Department of Veterinary and Animal Sciences, University of Massachusetts at Amherst, Amherst, MA 01003, USA
| | - Michael Y Choi
- Gastrointestinal Unit, Department of Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA; Harvard Stem Cell Institute, Cambridge, MA 02138, USA
| | - Alan C Mullen
- Gastrointestinal Unit, Department of Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA; Harvard Stem Cell Institute, Cambridge, MA 02138, USA.
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20
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Zinad HS, Natasya I, Werner A. Natural Antisense Transcripts at the Interface between Host Genome and Mobile Genetic Elements. Front Microbiol 2017; 8:2292. [PMID: 29209299 PMCID: PMC5701935 DOI: 10.3389/fmicb.2017.02292] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2017] [Accepted: 11/06/2017] [Indexed: 12/26/2022] Open
Abstract
Non-coding RNAs are involved in epigenetic processes, playing a role in the regulation of gene expression at the transcriptional and post-transcriptional levels. A particular group of ncRNA are natural antisense transcripts (NATs); these are transcribed in the opposite direction to protein coding transcripts and are widespread in eukaryotes. Their abundance, evidence of phylogenetic conservation and an increasing number of well-characterized examples of antisense-mediated gene regulation are indicative of essential biological roles of NATs. There is evidence to suggest that they interfere with their corresponding sense transcript to elicit concordant and discordant regulation. The main mechanisms involved include transcriptional interference as well as dsRNA formation. Sense–antisense hybrid formation can trigger RNA interference, RNA editing or protein kinase R. However, the exact molecular mechanisms elicited by NATs in the context of these regulatory roles are currently poorly understood. Several examples confirm that ectopic expression of antisense transcripts trigger epigenetic silencing of the related sense transcript. Genomic approaches suggest that the antisense transcriptome carries a broader biological significance which goes beyond the physiological regulation of the directly related sense transcripts. Because NATs show evidence of conservation we speculate that they played a role in evolution, with early eukaryotes gaining selective advantage through the regulatory effects. With the surge of genome and transcriptome sequencing projects, there is promise of a more comprehensive understanding of the biological role of NATs and the regulatory mechanisms involved.
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Affiliation(s)
- Hany S Zinad
- RNA Interest Group, Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Inas Natasya
- RNA Interest Group, Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle upon Tyne, United Kingdom
| | - Andreas Werner
- RNA Interest Group, Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle upon Tyne, United Kingdom
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21
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Wyler E, Menegatti J, Franke V, Kocks C, Boltengagen A, Hennig T, Theil K, Rutkowski A, Ferrai C, Baer L, Kermas L, Friedel C, Rajewsky N, Akalin A, Dölken L, Grässer F, Landthaler M. Widespread activation of antisense transcription of the host genome during herpes simplex virus 1 infection. Genome Biol 2017; 18:209. [PMID: 29089033 PMCID: PMC5663069 DOI: 10.1186/s13059-017-1329-5] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2017] [Accepted: 09/29/2017] [Indexed: 12/19/2022] Open
Abstract
Background Herpesviruses can infect a wide range of animal species. Herpes simplex virus 1 (HSV-1) is one of the eight herpesviruses that can infect humans and is prevalent worldwide. Herpesviruses have evolved multiple ways to adapt the infected cells to their needs, but knowledge about these transcriptional and post-transcriptional modifications is sparse. Results Here, we show that HSV-1 induces the expression of about 1000 antisense transcripts from the human host cell genome. A subset of these is also activated by the closely related varicella zoster virus. Antisense transcripts originate either at gene promoters or within the gene body, and they show different susceptibility to the inhibition of early and immediate early viral gene expression. Overexpression of the major viral transcription factor ICP4 is sufficient to turn on a subset of antisense transcripts. Histone marks around transcription start sites of HSV-1-induced and constitutively transcribed antisense transcripts are highly similar, indicating that the genetic loci are already poised to transcribe these novel RNAs. Furthermore, an antisense transcript overlapping with the BBC3 gene (also known as PUMA) transcriptionally silences this potent inducer of apoptosis in cis. Conclusions We show for the first time that a virus induces widespread antisense transcription of the host cell genome. We provide evidence that HSV-1 uses this to downregulate a strong inducer of apoptosis. Our findings open new perspectives on global and specific alterations of host cell transcription by viruses. Electronic supplementary material The online version of this article (doi:10.1186/s13059-017-1329-5) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Emanuel Wyler
- Berlin Institute for Medical Systems Biology, Max-Delbrück-Center for Molecular Medicine in the Helmholtz Association, Robert-Rössle-Strasse 10, 13125, Berlin, Germany
| | - Jennifer Menegatti
- Institute of Virology, Saarland University Medical School, Kirrbergerstrasse, Haus 47, 66421, Homburg/Saar, Germany
| | - Vedran Franke
- Berlin Institute for Medical Systems Biology, Max-Delbrück-Center for Molecular Medicine in the Helmholtz Association, Robert-Rössle-Strasse 10, 13125, Berlin, Germany
| | - Christine Kocks
- Berlin Institute for Medical Systems Biology, Max-Delbrück-Center for Molecular Medicine in the Helmholtz Association, Robert-Rössle-Strasse 10, 13125, Berlin, Germany
| | - Anastasiya Boltengagen
- Berlin Institute for Medical Systems Biology, Max-Delbrück-Center for Molecular Medicine in the Helmholtz Association, Robert-Rössle-Strasse 10, 13125, Berlin, Germany
| | - Thomas Hennig
- Institut für Virologie und Immunbiologie, Julius-Maximilians-Universität Würzburg, Versbacherstr. 7, 97078, Würzburg, Germany
| | - Kathrin Theil
- Berlin Institute for Medical Systems Biology, Max-Delbrück-Center for Molecular Medicine in the Helmholtz Association, Robert-Rössle-Strasse 10, 13125, Berlin, Germany
| | - Andrzej Rutkowski
- Department of Medicine, University of Cambridge, Addenbrookes Hospital, Box 157, Hills Rd, Cambridge, CB2 0QQ, UK.,Present address: AstraZeneca, Darwin Building, 310 Cambridge Science Park, Cambridge, CB4 0WG, UK
| | - Carmelo Ferrai
- Berlin Institute for Medical Systems Biology, Max-Delbrück-Center for Molecular Medicine in the Helmholtz Association, Robert-Rössle-Strasse 10, 13125, Berlin, Germany
| | - Laura Baer
- Institute of Virology, Saarland University Medical School, Kirrbergerstrasse, Haus 47, 66421, Homburg/Saar, Germany
| | - Lisa Kermas
- Berlin Institute for Medical Systems Biology, Max-Delbrück-Center for Molecular Medicine in the Helmholtz Association, Robert-Rössle-Strasse 10, 13125, Berlin, Germany
| | - Caroline Friedel
- Institut für Informatik, Ludwig-Maximilians-Universität München, Amalienstraße 17, 80333, München, Germany
| | - Nikolaus Rajewsky
- Berlin Institute for Medical Systems Biology, Max-Delbrück-Center for Molecular Medicine in the Helmholtz Association, Robert-Rössle-Strasse 10, 13125, Berlin, Germany
| | - Altuna Akalin
- Berlin Institute for Medical Systems Biology, Max-Delbrück-Center for Molecular Medicine in the Helmholtz Association, Robert-Rössle-Strasse 10, 13125, Berlin, Germany
| | - Lars Dölken
- Institut für Virologie und Immunbiologie, Julius-Maximilians-Universität Würzburg, Versbacherstr. 7, 97078, Würzburg, Germany
| | - Friedrich Grässer
- Institute of Virology, Saarland University Medical School, Kirrbergerstrasse, Haus 47, 66421, Homburg/Saar, Germany.
| | - Markus Landthaler
- Berlin Institute for Medical Systems Biology, Max-Delbrück-Center for Molecular Medicine in the Helmholtz Association, Robert-Rössle-Strasse 10, 13125, Berlin, Germany. .,IRI Life Sciences, Institute für Biologie, Humboldt Universität zu Berlin, Philippstraße 13, 10115, Berlin, Germany.
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22
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Lingering Questions about Enhancer RNA and Enhancer Transcription-Coupled Genomic Instability. Trends Genet 2017; 33:143-154. [PMID: 28087167 DOI: 10.1016/j.tig.2016.12.002] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2016] [Revised: 09/22/2016] [Accepted: 12/08/2016] [Indexed: 12/12/2022]
Abstract
Intergenic and intragenic enhancers found inside topologically associated regulatory domains (TADs) express noncoding RNAs, known as enhancer RNAs (eRNAs). Recent studies have indicated these eRNAs play a role in gene regulatory networks by controlling promoter and enhancer interactions and topology of higher-order chromatin structure. Misregulation of enhancer and promoter associated noncoding RNAs (ncRNAs) could stabilize deleterious secondary DNA structures, noncoding RNA associated DNA/RNA hybrid formation, and promote collisions of transcription complexes with replisomes. It is revealing that many chromosomal aberrations, some associated with malignancies, are present inside enhancer and/or promoter sequences. Here, we expand on current concepts to discuss enhancer RNAs and enhancer transcription, and how enhancer transcription influences genomic organization and integrity.
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23
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Nascent Connections: R-Loops and Chromatin Patterning. Trends Genet 2016; 32:828-838. [PMID: 27793359 DOI: 10.1016/j.tig.2016.10.002] [Citation(s) in RCA: 148] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2016] [Revised: 10/03/2016] [Accepted: 10/06/2016] [Indexed: 11/22/2022]
Abstract
RNA molecules, such as long noncoding RNAs (lncRNAs), have critical roles in regulating gene expression, chromosome architecture, and the modification states of chromatin. Recent developments suggest that RNA also influences gene expression and chromatin patterns through the interaction of nascent transcripts with their DNA template via the formation of co-transcriptional R-loop structures. R-loop formation over specific, conserved, hotspots occurs at thousands of genes in mammalian genomes and represents an important and dynamic feature of mammalian chromatin. Here, focusing primarily on mammalian systems, I describe the accumulating connections and possible mechanisms linking R-loop formation and chromatin patterning. The possible contribution of aberrant R-loops to pathological conditions is also discussed.
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24
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Roy K, Gabunilas J, Gillespie A, Ngo D, Chanfreau GF. Common genomic elements promote transcriptional and DNA replication roadblocks. Genome Res 2016; 26:1363-1375. [PMID: 27540088 PMCID: PMC5052057 DOI: 10.1101/gr.204776.116] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2016] [Accepted: 08/18/2016] [Indexed: 11/25/2022]
Abstract
RNA polymerase II (Pol II) transcription termination by the Nrd1p-Nab3p-Sen1p (NNS) pathway is critical for the production of stable noncoding RNAs and the control of pervasive transcription in Saccharomyces cerevisiae. To uncover determinants of NNS termination, we mapped the 3′-ends of NNS-terminated transcripts genome-wide. We found that nucleosomes and specific DNA-binding proteins, including the general regulatory factors (GRFs) Reb1p, Rap1p, and Abf1p, and Pol III transcription factors enhance the efficiency of NNS termination by physically blocking Pol II progression. The same DNA-bound factors that promote NNS termination were shown previously to define the 3′-ends of Okazaki fragments synthesized by Pol δ during DNA replication. Reduced binding of these factors results in defective NNS termination and Pol II readthrough. Furthermore, inactivating NNS enables Pol II elongation through these roadblocks, demonstrating that effective Pol II termination depends on a synergy between the NNS machinery and obstacles in chromatin. Consistent with this finding, loci exhibiting Pol II readthrough at GRF binding sites are depleted for upstream NNS signals. Overall, these results underscore how RNA termination signals influence the behavior of Pol II at chromatin obstacles, and establish that common genomic elements define boundaries for both DNA and RNA synthesis machineries.
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Affiliation(s)
- Kevin Roy
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, California 90095-1569, USA; Molecular Biology Institute, University of California, Los Angeles, Los Angeles, California 90095-1570, USA
| | - Jason Gabunilas
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, California 90095-1569, USA
| | - Abigail Gillespie
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, California 90095-1569, USA
| | - Duy Ngo
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, California 90095-1569, USA
| | - Guillaume F Chanfreau
- Department of Chemistry and Biochemistry, University of California, Los Angeles, Los Angeles, California 90095-1569, USA; Molecular Biology Institute, University of California, Los Angeles, Los Angeles, California 90095-1570, USA
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Sanz LA, Hartono SR, Lim YW, Steyaert S, Rajpurkar A, Ginno PA, Xu X, Chédin F. Prevalent, Dynamic, and Conserved R-Loop Structures Associate with Specific Epigenomic Signatures in Mammals. Mol Cell 2016; 63:167-78. [PMID: 27373332 DOI: 10.1016/j.molcel.2016.05.032] [Citation(s) in RCA: 365] [Impact Index Per Article: 45.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2015] [Revised: 01/11/2016] [Accepted: 05/23/2016] [Indexed: 11/28/2022]
Abstract
R-loops are three-stranded nucleic acid structures formed upon annealing of an RNA strand to one strand of duplex DNA. We profiled R-loops using a high-resolution, strand-specific methodology in human and mouse cell types. R-loops are prevalent, collectively occupying up to 5% of mammalian genomes. R-loop formation occurs over conserved genic hotspots such as promoter and terminator regions of poly(A)-dependent genes. In most cases, R-loops occur co-transcriptionally and undergo dynamic turnover. Detailed epigenomic profiling revealed that R-loops associate with specific chromatin signatures. At promoters, R-loops associate with a hyper-accessible state characteristic of unmethylated CpG island promoters. By contrast, terminal R-loops associate with an enhancer- and insulator-like state and define a broad class of transcription terminators. Together, this suggests that the retention of nascent RNA transcripts at their site of expression represents an abundant, dynamic, and programmed component of the mammalian chromatin that affects chromatin patterning and the control of gene expression.
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Affiliation(s)
- Lionel A Sanz
- Department of Molecular and Cellular Biology and Genome Center, 1 Shields Avenue, University of California, Davis, Davis, CA 95616, USA
| | - Stella R Hartono
- Department of Molecular and Cellular Biology and Genome Center, 1 Shields Avenue, University of California, Davis, Davis, CA 95616, USA
| | - Yoong Wearn Lim
- Department of Molecular and Cellular Biology and Genome Center, 1 Shields Avenue, University of California, Davis, Davis, CA 95616, USA
| | - Sandra Steyaert
- Department of Mathematical Modeling, Statistics, and Bioinformatics, University of Ghent, Ghent 9000, Belgium
| | - Aparna Rajpurkar
- Department of Molecular and Cellular Biology and Genome Center, 1 Shields Avenue, University of California, Davis, Davis, CA 95616, USA
| | - Paul A Ginno
- Department of Molecular and Cellular Biology and Genome Center, 1 Shields Avenue, University of California, Davis, Davis, CA 95616, USA
| | - Xiaoqin Xu
- Department of Molecular and Cellular Biology and Genome Center, 1 Shields Avenue, University of California, Davis, Davis, CA 95616, USA
| | - Frédéric Chédin
- Department of Molecular and Cellular Biology and Genome Center, 1 Shields Avenue, University of California, Davis, Davis, CA 95616, USA.
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26
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Mostovoy Y, Thiemicke A, Hsu TY, Brem RB. The Role of Transcription Factors at Antisense-Expressing Gene Pairs in Yeast. Genome Biol Evol 2016; 8:1748-61. [PMID: 27190003 PMCID: PMC4943177 DOI: 10.1093/gbe/evw104] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Genes encoded close to one another on the chromosome are often coexpressed, by a mechanism and regulatory logic that remain poorly understood. We surveyed the yeast genome for tandem gene pairs oriented tail-to-head at which expression antisense to the upstream gene was conserved across species. The intergenic region at most such tandem pairs is a bidirectional promoter, shared by the downstream gene mRNA and the upstream antisense transcript. Genomic analyses of these intergenic loci revealed distinctive patterns of transcription factor regulation. Mutation of a given transcription factor verified its role as a regulator in trans of tandem gene pair loci, including the proximally initiating upstream antisense transcript and downstream mRNA and the distally initiating upstream mRNA. To investigate cis-regulatory activity at such a locus, we focused on the stress-induced NAD(P)H dehydratase YKL151C and its downstream neighbor, the metabolic enzyme GPM1. Previous work has implicated the region between these genes in regulation of GPM1 expression; our mutation experiments established its function in rich medium as a repressor in cis of the distally initiating YKL151C sense RNA, and an activator of the proximally initiating YKL151C antisense RNA. Wild-type expression of all three transcripts required the transcription factor Gcr2. Thus, at this locus, the intergenic region serves as a focal point of regulatory input, driving antisense expression and mediating the coordinated regulation of YKL151C and GPM1. Together, our findings implicate transcription factors in the joint control of neighboring genes specialized to opposing conditions and the antisense transcripts expressed between them.
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Affiliation(s)
- Yulia Mostovoy
- Department of Molecular and Cell Biology, University of California, Berkeley, California Present address: Cardiovascular Research Institute, University of California, San Francisco, CA
| | - Alexander Thiemicke
- Department of Molecular and Cell Biology, University of California, Berkeley, California Program in Molecular Medicine, Friedrich-Schiller-Universität, Jena, Germany Present address: Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN
| | - Tiffany Y Hsu
- Department of Molecular and Cell Biology, University of California, Berkeley, California Present address: Graduate Program in Biological and Biomedical Sciences, Harvard Medical School, Boston, MA
| | - Rachel B Brem
- Department of Molecular and Cell Biology, University of California, Berkeley, California Present address: Buck Institute for Research on Aging, Novato, CA
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Precision Modulation of Neurodegenerative Disease-Related Gene Expression in Human iPSC-Derived Neurons. Sci Rep 2016; 6:28420. [PMID: 27341390 PMCID: PMC4920027 DOI: 10.1038/srep28420] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2016] [Accepted: 05/16/2016] [Indexed: 12/22/2022] Open
Abstract
The ability to reprogram adult somatic cells into induced pluripotent stem cells (iPSCs) and the subsequent development of protocols for their differentiation into disease-relevant cell types have enabled in-depth molecular analyses of multiple disease states as hitherto impossible. Neurons differentiated from patient-specific iPSCs provide a means to recapitulate molecular phenotypes of neurodegenerative diseases in vitro. However, it remains challenging to conduct precise manipulations of gene expression in iPSC-derived neurons towards modeling complex human neurological diseases. The application of CRISPR/Cas9 to mammalian systems is revolutionizing the utilization of genome editing technologies in the study of molecular contributors to the pathogenesis of numerous diseases. Here, we demonstrate that CRISPRa and CRISPRi can be used to exert precise modulations of endogenous gene expression in fate-committed iPSC-derived neurons. This highlights CRISPRa/i as a major technical advancement in accessible tools for evaluating the specific contributions of critical neurodegenerative disease-related genes to neuropathogenesis.
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28
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Jabasini M, Ewis A, Sato Y, Nakahori Y, Baba Y. Anomalous Separation of Small Y-Chromosomal DNA Fragments on Microchip Electrophoresis. Sci Pharm 2016; 84:507-513. [PMID: 28117316 PMCID: PMC5064241 DOI: 10.3390/scipharm84030507] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2016] [Accepted: 05/13/2016] [Indexed: 11/16/2022] Open
Abstract
We investigated an anomalous DNA separation where two DNA fragments from the human Y-chromosome sY638 (64 bp) and sY592 (65 bp), with only one base pair difference, were separated. This result is abnormal since in a previous study, we found that 5 bp was the minimum difference between two DNA fragments that the microchip electrophoresis system can separate. The formation of a mini-loop in the structure of the DNA fragment of sY638 (64 bp) was strongly expected to be the reason. To investigate this, we synthesized three modified DNA fragments for sY638 (64 bp), and the modifications were in two expected locations for possible mini-loop formation. Later, the separation between sY592 (65 bp) and the three modified fragments of sY638 (64 bp) was not possible. Thus, we conclude that the formation of a mini-loop in the structure of the DNA is the reason behind this anomalous separation.
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Affiliation(s)
- Mohammad Jabasini
- Department of Pharmaceutical Information Science, Institute of Health Biosciences, The University of Tokushima, 1-78-1 Sho-machi, 770-8505 Tokushima, Japan.
- Department of Applied Chemistry, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, 464-8603 Nagoya, Japan.
| | - Ashraf Ewis
- Department of Human Genetics Public Health, School of Medicine, The University of Tokushima, 3-18-15 Kuramoto-cho, 770-8503 Tokushima, Japan.
| | - Youichi Sato
- Department of Pharmaceutical Information Science, Institute of Health Biosciences, The University of Tokushima, 1-78-1 Sho-machi, 770-8505 Tokushima, Japan.
| | - Yutaka Nakahori
- Department of Human Genetics Public Health, School of Medicine, The University of Tokushima, 3-18-15 Kuramoto-cho, 770-8503 Tokushima, Japan.
| | - Yoshinobu Baba
- Department of Applied Chemistry, Graduate School of Engineering, Nagoya University, Furo-cho, Chikusa-ku, 464-8603 Nagoya, Japan.
- ImPACT Research Center for Advanced Nanobiodevices., Nagoya University, Furo-cho, Chikusa-ku, 464-8603 Nagoya, Japan.
- Health Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Hayashi-cho 2217-14, 761-0395 Takamatsu, Japan.
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29
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Lacadie SA, Ibrahim MM, Gokhale SA, Ohler U. Divergent transcription and epigenetic directionality of human promoters. FEBS J 2016; 283:4214-4222. [DOI: 10.1111/febs.13747] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2015] [Revised: 02/08/2016] [Accepted: 04/25/2016] [Indexed: 11/26/2022]
Affiliation(s)
- Scott A. Lacadie
- Berlin Institute for Medical Systems Biology; Max Delbrück Center for Molecular Medicine; Berlin Germany
- Berlin Institute of Health (BIH); Germany
| | - Mahmoud M. Ibrahim
- Berlin Institute for Medical Systems Biology; Max Delbrück Center for Molecular Medicine; Berlin Germany
- Department of Biology; Humboldt University Berlin; Germany
| | - Sucheta A. Gokhale
- Berlin Institute for Medical Systems Biology; Max Delbrück Center for Molecular Medicine; Berlin Germany
| | - Uwe Ohler
- Berlin Institute for Medical Systems Biology; Max Delbrück Center for Molecular Medicine; Berlin Germany
- Berlin Institute of Health (BIH); Germany
- Department of Biology; Humboldt University Berlin; Germany
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Agarwal N, Ansari A. Enhancement of Transcription by a Splicing-Competent Intron Is Dependent on Promoter Directionality. PLoS Genet 2016; 12:e1006047. [PMID: 27152651 PMCID: PMC4859611 DOI: 10.1371/journal.pgen.1006047] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2016] [Accepted: 04/20/2016] [Indexed: 11/23/2022] Open
Abstract
Enhancement of transcription by a splicing-competent intron is an evolutionarily conserved feature among eukaryotes. The molecular mechanism underlying the phenomenon, however, is not entirely clear. Here we show that the intron is an important regulator of promoter directionality. Employing strand-specific transcription run-on (TRO) analysis, we show that the transcription of mRNA is favored over the upstream anti-sense transcripts (uaRNA) initiating from the promoter in the presence of an intron. Mutation of either the 5′ or 3′ splice site resulted in the reversal of promoter directionality, thereby suggesting that it is not merely the 5′ splice site but the entire splicing-competent intron that regulates transcription directionality. ChIP analysis revealed the recruitment of termination factors near the promoter region in the presence of an intron. Removal of intron or the mutation of splice sites adversely affected the promoter localization of termination factors. We have earlier demonstrated that the intron-mediated enhancement of transcription is dependent on gene looping. Here we show that gene looping is crucial for the recruitment of termination factors in the promoter-proximal region of an intron-containing gene. In a looping-defective mutant, despite normal splicing, the promoter occupancy of factors required for poly(A)-dependent termination of transcription was compromised. This was accompanied by a concomitant loss of transcription directionality. On the basis of these results, we propose that the intron-dependent gene looping places the terminator-bound factors in the vicinity of the promoter region for termination of the promoter-initiated upstream antisense transcription, thereby conferring promoter directionality. Eukaryotic genes differ from their prokaryotic counterparts in having intervening non-coding sequences called introns. The precise biological role of introns in eukaryotic systems remains unclear even more than forty years after their initial discovery. One function of intron that has been remarkably conserved during evolution is their ability to enhance the transcription of genes that harbor them. How does the intron regulate transcription, however, is not known. Here we show that the intron enhances gene expression by affecting direction of the promoter-initiated transcription. In the presence of an intron, polymerase tends to transcribe the downstream coding region producing mRNA, while in the absence of a splicing-competent intron polymerase starts transcribing promoter upstream region producing upstream antisense RNA (uaRNA). Intron-mediated promoter directionality was dependent on gene looping, which is the interaction off the promoter and terminator region of a gene in a transcription-dependent manner. We show that the intron-dependent gene looping facilitates the recruitment of termination factors in the promoter-proximal region. The recruited termination factors stop uaRNA synthesis thereby conferring directionality to the promoter-bound polymerase.
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Affiliation(s)
- Neha Agarwal
- Department of Biological Sciences, Wayne State University, Detroit, Michigan, United States of America
| | - Athar Ansari
- Department of Biological Sciences, Wayne State University, Detroit, Michigan, United States of America
- * E-mail:
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31
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Abstract
Long non-coding RNAs (lncRNAs) are a diverse class of RNAs that engage in numerous biological processes across every branch of life. Although initially discovered as mRNA-like transcripts that do not encode proteins, recent studies have revealed features of lncRNAs that further distinguish them from mRNAs. In this Review, we describe special events in the lifetimes of lncRNAs - before, during and after transcription - and discuss how these events ultimately shape the unique characteristics and functional roles of lncRNAs.
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Affiliation(s)
- Jeffrey J Quinn
- Center for Personal Dynamic Regulomes, Stanford University School of Medicine, Stanford, California 94305, USA.,Department of Bioengineering, Stanford University School of Medicine and School of Engineering, Stanford, California 94305, USA
| | - Howard Y Chang
- Center for Personal Dynamic Regulomes, Stanford University School of Medicine, Stanford, California 94305, USA
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32
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Abstract
All living organisms sense and respond to harmful changes in their intracellular and extracellular environment through complex signaling pathways that lead to changes in gene expression and cellular function in order to maintain homeostasis. Long non-coding RNAs (lncRNAs), a large and heterogeneous group of functional RNAs, play important roles in cellular response to stressful conditions. lncRNAs constitute a significant fraction of the genes differentially expressed in response to diverse stressful stimuli and, once induced, contribute to the regulation of downstream cellular processes, including feedback regulation of key stress response proteins. While many lncRNAs seem to be induced in response to a specific stress, there is significant overlap between lncRNAs induced in response to different stressful stimuli. In addition to stress-induced RNAs, several constitutively expressed lncRNAs also exert a strong regulatory impact on the stress response. Although our understanding of the contribution of lncRNAs to the cellular stress response is still highly rudimentary, the existing data point to the presence of a complex network of lncRNAs, miRNAs, and proteins in regulation of the cellular response to stress.
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Affiliation(s)
- Saba Valadkhan
- Department of Molecular Biology and Microbiology, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA.
| | - Alberto Valencia-Hipólito
- Department of Molecular Biology and Microbiology, Case Western Reserve University School of Medicine, Cleveland, OH, 44106, USA
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33
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Beilharz TH. Understanding the regulation of coding and noncoding transcription in cell populations. Curr Genet 2015; 62:317-9. [PMID: 26660659 DOI: 10.1007/s00294-015-0547-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2015] [Revised: 11/18/2015] [Accepted: 11/20/2015] [Indexed: 11/30/2022]
Abstract
Whole transcriptome analyses have unveiled the uncomfortable truth that we know less about how transcription is regulated then we thought. In addition to its role in classic promoter-driven transcription of coding RNA, it is now clear that RNA Pol II also drives abundant expression of noncoding RNA. For the majority of this the functional significance remains unclear. Moreover, its regulation and impact are hard to predict because it often proceeds in unexpected ways from cryptic promoters, including by driving convergent antisense transcription from within 3' UTRs. This review suggests that its time to rethink how we envisage gene expression by inclusion of the regulatory architecture of the full genetic locus, and expanding our thinking to encompass the fact that we generally study cells within heterogeneous populations.
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Affiliation(s)
- Traude Helene Beilharz
- Development and Stem Cells Program, Department of Biochemistry and Molecular Biology, Monash Biomedicine Discovery Institute, Monash University, Melbourne, VIC, 3800, Australia.
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34
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Sexton T, Cavalli G. The role of chromosome domains in shaping the functional genome. Cell 2015; 160:1049-59. [PMID: 25768903 DOI: 10.1016/j.cell.2015.02.040] [Citation(s) in RCA: 271] [Impact Index Per Article: 30.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2014] [Indexed: 10/23/2022]
Abstract
The genome must be highly compacted to fit within eukaryotic nuclei but must be accessible to the transcriptional machinery to allow appropriate expression of genes in different cell types and throughout developmental pathways. A growing body of work has shown that the genome, analogously to proteins, forms an ordered, hierarchical structure that closely correlates and may even be causally linked with regulation of functions such as transcription. This review describes our current understanding of how these functional genomic "secondary and tertiary structures" form a blueprint for global nuclear architecture and the potential they hold for understanding and manipulating genomic regulation.
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Affiliation(s)
- Tom Sexton
- Institute of Genetics and Molecular and Cellular Biology (IGBMC), 1 rue Laurent Fries, 67404 Illkirch, France.
| | - Giacomo Cavalli
- Institute of Human Genetics (IGH), 141 rue de la Cardonille, 34396 Montpellier, France.
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35
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Duttke SHC, Lacadie SA, Ibrahim MM, Glass CK, Corcoran DL, Benner C, Heinz S, Kadonaga JT, Ohler U. Human promoters are intrinsically directional. Mol Cell 2015; 57:674-684. [PMID: 25639469 DOI: 10.1016/j.molcel.2014.12.029] [Citation(s) in RCA: 102] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2014] [Revised: 11/19/2014] [Accepted: 12/16/2014] [Indexed: 10/24/2022]
Abstract
Divergent transcription, in which reverse-oriented transcripts occur upstream of eukaryotic promoters in regions devoid of annotated genes, has been suggested to be a general property of active promoters. Here we show that the human basal RNA polymerase II transcriptional machinery and core promoter are inherently unidirectional and that reverse-oriented transcripts originate from their own cognate reverse-directed core promoters. In vitro transcription analysis and mapping of nascent transcripts in HeLa cells revealed that sequences at reverse start sites are similar to those of their forward counterparts. The use of DNase I accessibility to define proximal promoter borders revealed that about half of promoters are unidirectional and that unidirectional promoters are depleted at their upstream edges of reverse core promoter sequences and their associated chromatin features. Divergent transcription is thus not an inherent property of the transcription process but rather the consequence of the presence of both forward- and reverse-directed core promoters.
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Affiliation(s)
- Sascha H C Duttke
- Section of Molecular Biology, University of California, San Diego, La Jolla, CA 92093, USA
| | - Scott A Lacadie
- Berlin Institute for Medical Systems Biology, Max Delbrück Center for Molecular Medicine, 13125 Berlin, Germany
| | - Mahmoud M Ibrahim
- Berlin Institute for Medical Systems Biology, Max Delbrück Center for Molecular Medicine, 13125 Berlin, Germany; Department of Biology, Humboldt University, 10115 Berlin, Germany
| | - Christopher K Glass
- Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA 92093, USA; Department of Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - David L Corcoran
- Center for Genomic and Computational Biology, Duke University, Durham, NC 27708, USA
| | | | - Sven Heinz
- Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA 92093, USA; Salk Institute for Biological Studies, La Jolla, CA 92037, USA
| | - James T Kadonaga
- Section of Molecular Biology, University of California, San Diego, La Jolla, CA 92093, USA.
| | - Uwe Ohler
- Berlin Institute for Medical Systems Biology, Max Delbrück Center for Molecular Medicine, 13125 Berlin, Germany; Department of Biology, Humboldt University, 10115 Berlin, Germany.
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36
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Chen Y, Zhang L, Estarás C, Choi SH, Moreno L, Karn J, Moresco JJ, Yates JR, Jones KA. A gene-specific role for the Ssu72 RNAPII CTD phosphatase in HIV-1 Tat transactivation. Genes Dev 2014; 28:2261-75. [PMID: 25319827 PMCID: PMC4201287 DOI: 10.1101/gad.250449.114] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
HIV-1 Tat stimulates transcription elongation by recruiting the P-TEFb (positive transcription elongation factor-b) (CycT1:CDK9) C-terminal domain (CTD) kinase to the HIV-1 promoter. Here we show that Tat transactivation also requires the Ssu72 CTD Ser5P (S5P)-specific phosphatase, which mediates transcription termination and intragenic looping at eukaryotic genes. Importantly, HIV-1 Tat interacts directly with Ssu72 and strongly stimulates its CTD phosphatase activity. We found that Ssu72 is essential for Tat:P-TEFb-mediated phosphorylation of the S5P-CTD in vitro. Interestingly, Ssu72 also stimulates nascent HIV-1 transcription in a phosphatase-dependent manner in vivo. Chromatin immunoprecipitation (ChIP) experiments reveal that Ssu72, like P-TEFb and AFF4, is recruited by Tat to the integrated HIV-1 proviral promoter in TNF-α signaling 2D10 T cells and leaves the elongation complex prior to the termination site. ChIP-seq (ChIP combined with deep sequencing) and GRO-seq (genome-wide nuclear run-on [GRO] combined with deep sequencing) analysis further reveals that Ssu72 predominantly colocalizes with S5P-RNAPII (RNA polymerase II) at promoters in human embryonic stem cells, with a minor peak in the terminator region. A few genes, like NANOG, also have high Ssu72 at the terminator. Ssu72 is not required for transcription at most cellular genes but has a modest effect on cotranscriptional termination. We conclude that Tat alters the cellular function of Ssu72 to stimulate viral gene expression and facilitate the early S5P-S2P transition at the integrated HIV-1 promoter.
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Affiliation(s)
- Yupeng Chen
- Regulatory Biology Laboratory, The Salk Institute for Biological Studies, La Jolla, California 92037, USA
| | - Lirong Zhang
- Regulatory Biology Laboratory, The Salk Institute for Biological Studies, La Jolla, California 92037, USA
| | - Conchi Estarás
- Regulatory Biology Laboratory, The Salk Institute for Biological Studies, La Jolla, California 92037, USA
| | - Seung H Choi
- Regulatory Biology Laboratory, The Salk Institute for Biological Studies, La Jolla, California 92037, USA
| | - Luis Moreno
- Regulatory Biology Laboratory, The Salk Institute for Biological Studies, La Jolla, California 92037, USA
| | - Jonathan Karn
- Department of Molecular Biology and Microbiology, Case Western Reserve University School of Medicine, Cleveland, Ohio 44106, USA
| | - James J Moresco
- Department of Chemical Physiology and Cell Biology, The Scripps Research Institute, La Jolla, California 92037, USA
| | - John R Yates
- Department of Chemical Physiology and Cell Biology, The Scripps Research Institute, La Jolla, California 92037, USA
| | - Katherine A Jones
- Regulatory Biology Laboratory, The Salk Institute for Biological Studies, La Jolla, California 92037, USA;
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37
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Schaughency P, Merran J, Corden JL. Genome-wide mapping of yeast RNA polymerase II termination. PLoS Genet 2014; 10:e1004632. [PMID: 25299594 PMCID: PMC4191890 DOI: 10.1371/journal.pgen.1004632] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2014] [Accepted: 07/21/2014] [Indexed: 12/22/2022] Open
Abstract
Yeast RNA polymerase II (Pol II) terminates transcription of coding transcripts through the polyadenylation (pA) pathway and non-coding transcripts through the non-polyadenylation (non-pA) pathway. We have used PAR-CLIP to map the position of Pol II genome-wide in living yeast cells after depletion of components of either the pA or non-pA termination complexes. We show here that Ysh1, responsible for cleavage at the pA site, is required for efficient removal of Pol II from the template. Depletion of Ysh1 from the nucleus does not, however, lead to readthrough transcription. In contrast, depletion of the termination factor Nrd1 leads to widespread runaway elongation of non-pA transcripts. Depletion of Sen1 also leads to readthrough at non-pA terminators, but in contrast to Nrd1, this readthrough is less processive, or more susceptible to pausing. The data presented here provide delineation of in vivo Pol II termination regions and highlight differences in the sequences that signal termination of different classes of non-pA transcripts. Transcription termination is an important regulatory event for both non-coding and coding transcripts. Using high-throughput sequencing, we have mapped RNA Polymerase II's position in the genome after depletion of termination factors from the nucleus. We found that depletion of Ysh1 and Sen1 cause build up of polymerase directly downstream of coding and non-coding genes, respectively. Depletion of Nrd1 causes an increase in polymerase that is distributed up to 1,000 bases downstream of non-coding genes. The depletion of Nrd1 helped us to identify more than 250 unique termination regions for non-coding RNAs. Within this set of newly identified non-coding termination regions, we are further able to classify them based on sequence motif similarities, suggesting a functional role for different terminator motifs. The role of these factors in transcriptional termination of coding and/or non-coding transcripts can be inferred from the effect of polymerase's position downstream of given termination sites. This method of depletion and sequencing can be used to further elucidate other factors whose importance to transcription has yet to be determined.
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Affiliation(s)
- Paul Schaughency
- Department of Molecular Biology and Genetics, Johns Hopkins Medical School, Baltimore, Maryland, United States of America
| | - Jonathan Merran
- Department of Molecular Biology and Genetics, Johns Hopkins Medical School, Baltimore, Maryland, United States of America
| | - Jeffry L. Corden
- Department of Molecular Biology and Genetics, Johns Hopkins Medical School, Baltimore, Maryland, United States of America
- * E-mail:
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