1
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Boulanger C, Haidara N, Yague-Sanz C, Larochelle M, Jacques PÉ, Hermand D, Bachand F. Repression of pervasive antisense transcription is the primary role of fission yeast RNA polymerase II CTD serine 2 phosphorylation. Nucleic Acids Res 2024; 52:7572-7589. [PMID: 38801067 PMCID: PMC11260464 DOI: 10.1093/nar/gkae436] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2024] [Revised: 05/03/2024] [Accepted: 05/09/2024] [Indexed: 05/29/2024] Open
Abstract
The RNA polymerase II carboxy-terminal domain (CTD) consists of conserved heptapeptide repeats that can be phosphorylated to influence distinct stages of the transcription cycle, including RNA processing. Although CTD-associated proteins have been identified, phospho-dependent CTD interactions have remained elusive. Proximity-dependent biotinylation (PDB) has recently emerged as an alternative approach to identify protein-protein associations in the native cellular environment. In this study, we present a PDB-based map of the fission yeast RNAPII CTD interactome in living cells and identify phospho-dependent CTD interactions by using a mutant in which Ser2 was replaced by alanine in every repeat of the fission yeast CTD. This approach revealed that CTD Ser2 phosphorylation is critical for the association between RNAPII and the histone methyltransferase Set2 during transcription elongation, but is not required for 3' end processing and transcription termination. Accordingly, loss of CTD Ser2 phosphorylation causes a global increase in antisense transcription, correlating with elevated histone acetylation in gene bodies. Our findings reveal that the fundamental role of CTD Ser2 phosphorylation is to establish a chromatin-based repressive state that prevents cryptic intragenic transcription initiation.
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Affiliation(s)
- Cédric Boulanger
- RNA Group, Dept of Biochemistry & Functional Genomics, Université de Sherbrooke, Sherbrooke, Québec J1E 4K8, Canada
| | - Nouhou Haidara
- RNA Group, Dept of Biochemistry & Functional Genomics, Université de Sherbrooke, Sherbrooke, Québec J1E 4K8, Canada
| | - Carlo Yague-Sanz
- URPHYM-GEMO, The University of Namur, rue de Bruxelles, 61, Namur 5000, Belgium
| | - Marc Larochelle
- RNA Group, Dept of Biochemistry & Functional Genomics, Université de Sherbrooke, Sherbrooke, Québec J1E 4K8, Canada
| | | | - Damien Hermand
- URPHYM-GEMO, The University of Namur, rue de Bruxelles, 61, Namur 5000, Belgium
- The Francis Crick Institute, 1 Midland Road London NW1 1AT, UK
| | - Francois Bachand
- RNA Group, Dept of Biochemistry & Functional Genomics, Université de Sherbrooke, Sherbrooke, Québec J1E 4K8, Canada
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2
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Wang W, An X, Yan K, Li Q. Construction and Application of Orthogonal T7 Expression System in Eukaryote: An Overview. Adv Biol (Weinh) 2023; 7:e2200218. [PMID: 36464626 DOI: 10.1002/adbi.202200218] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2022] [Revised: 10/17/2022] [Indexed: 12/12/2022]
Abstract
The T7 system is an orthogonal transcription-system, which is characterized by simplicity, higher efficiency, and higher processivity, and it is used for protein or mRNA synthesis in various biological-systems. In comparison with prokaryotes, the construction of the T7 expression system is still on-going in eukaryotes, but it shows greatly applicable prospects. In the present paper, development of T7 expression system construction in eukaryotes is reviewed, including its construction in animal (mammalian cells, trypanosomatid protozoa, Xenopus oocytes, zebrafish), plant, and microorganism and its application in vaccine production and gene therapy. In addition, the innate challenges of T7 expression system construction in eukaryote and its potential application in vaccine production and gene therapy are discussed.
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Affiliation(s)
- Wenya Wang
- College of Life Science and Technology, Beijing University of Chemical Technology, Beijing, 100029, P. R. China
| | - Xiaoyan An
- College of Life Science and Technology, Beijing University of Chemical Technology, Beijing, 100029, P. R. China
| | - Kun Yan
- College of Life Science and Technology, Beijing University of Chemical Technology, Beijing, 100029, P. R. China
| | - Qiang Li
- Key Laboratory for Industrial Biocatalysis, Ministry of Education, Department of Chemical Engineering, Tsinghua University, Beijing, 100084, P. R. China
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3
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Presnell KV, Melhem O, Morse NJ, Alper HS. Modular, Synthetic Boolean Logic Gates Enabled in Saccharomyces cerevisiae through T7 Polymerases/CRISPR dCas9 Designs. ACS Synth Biol 2022; 11:3414-3425. [PMID: 36206523 DOI: 10.1021/acssynbio.2c00327] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Synthetic control of gene expression, whether simply promoter selection or higher-order Boolean-style logic, is an important tool for metabolic engineering and synthetic biology. This work develops a suite of orthogonal T7 RNA polymerase systems capable of exerting AND/OR switchlike control over transcription in the yeastSaccharomyces cerevisiae. When linked with CRISPR dCas9-based regulation systems, more complex circuitry is possible including AND/OR/NAND/NOR style control in response to combinations of extracellular copper and galactose. Additionally, we demonstrate that these T7 system designs are modular and can accommodate alternative stimuli sensing as demonstrated through blue light induction. These designs should greatly reduce the time and labor necessary for developing Boolean gene circuits in yeast with novel applications including metabolic pathway control in the future.
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Affiliation(s)
- Kristin V Presnell
- McKetta Department of Chemical Engineering, The University of Texas at Austin, 200 E Dean Keeton Street Stop C0400, Austin, Texas 78712, United States
| | - Omar Melhem
- McKetta Department of Chemical Engineering, The University of Texas at Austin, 200 E Dean Keeton Street Stop C0400, Austin, Texas 78712, United States
| | - Nicholas J Morse
- McKetta Department of Chemical Engineering, The University of Texas at Austin, 200 E Dean Keeton Street Stop C0400, Austin, Texas 78712, United States
| | - Hal S Alper
- McKetta Department of Chemical Engineering, The University of Texas at Austin, 200 E Dean Keeton Street Stop C0400, Austin, Texas 78712, United States.,Institute for Cellular and Molecular Biology, The University of Texas at Austin, 2500 Speedway Avenue, Austin, Texas 78712, United States
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4
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Sáez Moreno D, Udi Q, Azeredo J, Domingues L. Towards T7 RNA polymerase (T7RNAP)-based expression system in yeast: challenges and opportunities. Bioengineered 2022; 13:14947-14959. [PMID: 37105766 DOI: 10.1080/21655979.2023.2180579] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/29/2023] Open
Abstract
During the last decades, we have witnessed unprecedented advances in biological engineering and synthetic biology. These disciplines aim to take advantage of gene pathway regulation and gene expression in different organisms, to enable cells to perform desired functions. Yeast has been widely utilized as a model for the study of eukaryotic protein expression while bacteriophage T7RNAP and its promoter constitute the preferred system for prokaryotic protein expression (such as pET-based expression systems). The ability to integrate a T7RNAP-based expression system in yeast could allow for a better understanding of gene regulation in eukaryotic cells, and potentially increase the efficiency and processivity of yeast as an expression system. However, the attempts for the creation of such a system have been unsuccessful to date. This review aims to: (i) summarize the efforts that, for many years, have been devoted to the creation of a T7RNAP-based yeast expression system and ii) provide an overview of the latest advances in knowledge of eukaryotic transcription and translation that could lead to the construction of a successful T7RNAP expression system in yeast. The completion of this new expression system would allow to further expand the toolkit of yeast in synthetic biology and ultimately contribute to boost yeast usage as a key cell factory in sustainable biorefinery and circular economy.
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Affiliation(s)
- David Sáez Moreno
- CEB-Centre of Biological Engineering, University of Minho, 4710-057, Braga, Portugal
- LABBELS-Associate Laboratory, 4835-198, Guimarães, Braga, Portugal
| | - Qimron Udi
- Department of Clinical Microbiology and Immunology, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Joana Azeredo
- CEB-Centre of Biological Engineering, University of Minho, 4710-057, Braga, Portugal
- LABBELS-Associate Laboratory, 4835-198, Guimarães, Braga, Portugal
| | - Lucília Domingues
- CEB-Centre of Biological Engineering, University of Minho, 4710-057, Braga, Portugal
- LABBELS-Associate Laboratory, 4835-198, Guimarães, Braga, Portugal
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5
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Jensen ED, Laloux M, Lehka BJ, Pedersen LE, Jakočiūnas T, Jensen M, Keasling J. A synthetic RNA-mediated evolution system in yeast. Nucleic Acids Res 2021; 49:e88. [PMID: 34107026 PMCID: PMC8421215 DOI: 10.1093/nar/gkab472] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2021] [Revised: 04/13/2021] [Accepted: 05/18/2021] [Indexed: 11/19/2022] Open
Abstract
Laboratory evolution is a powerful approach to search for genetic adaptations to new or improved phenotypes, yet either relies on labour-intensive human-guided iterative rounds of mutagenesis and selection, or prolonged adaptation regimes based on naturally evolving cell populations. Here we present CRISPR- and RNA-assisted in vivo directed evolution (CRAIDE) of genomic loci using evolving chimeric donor gRNAs continuously delivered from an error-prone T7 RNA polymerase, and directly introduced as RNA repair donors into genomic targets under either Cas9 or dCas9 guidance. We validate CRAIDE by evolving novel functional variants of an auxotrophic marker gene, and by conferring resistance to a toxic amino acid analogue in baker's yeast Saccharomyces cerevisiae with a mutation rate >3,000-fold higher compared to spontaneous native rate, thus enabling the first demonstrations of in vivo delivery and information transfer from long evolving RNA donor templates into genomic context without the use of in vitro supplied and pre-programmed repair donors.
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Affiliation(s)
- Emil D Jensen
- Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kgs. Lyngby, Denmark
| | - Marcos Laloux
- Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kgs. Lyngby, Denmark
| | - Beata J Lehka
- Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kgs. Lyngby, Denmark
| | - Lasse E Pedersen
- Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kgs. Lyngby, Denmark
| | - Tadas Jakočiūnas
- Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kgs. Lyngby, Denmark
| | - Michael K Jensen
- Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kgs. Lyngby, Denmark
| | - Jay D Keasling
- Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Kgs. Lyngby, Denmark
- Joint BioEnergy Institute, Emeryville, CA, USA
- Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA
- Department of Chemical and Biomolecular Engineering & Department of Bioengineering, University of California, Berkeley, CA, USA
- Center for Synthetic Biochemistry, Institute for Synthetic Biology, Shenzhen Institutes of Advanced Technologies, Shenzhen, China
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6
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Randazzo P, Bennis NX, Daran JM, Daran-Lapujade P. gEL DNA: A Cloning- and Polymerase Chain Reaction-Free Method for CRISPR-Based Multiplexed Genome Editing. CRISPR J 2021; 4:896-913. [PMID: 33900846 DOI: 10.1089/crispr.2020.0028] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Even for the genetically accessible yeast Saccharomyces cerevisiae, the CRISPR-Cas DNA editing technology has strongly accelerated and facilitated strain construction. Several methods have been validated for fast and highly efficient single editing events, and diverse approaches for multiplex genome editing have been described in the literature by means of SpCas9 or FnCas12a endonucleases and their associated guide RNAs (gRNAs). The gRNAs used to guide the Cas endonuclease to the editing site are typically expressed from plasmids using native Pol II or Pol III RNA polymerases. These gRNA expression plasmids require laborious, time-consuming cloning steps, which hampers their implementation for academic and applied purposes. In this study, we explore the potential of expressing gRNA from linear DNA fragments using the T7 RNA polymerase (T7RNAP) for single and multiplex genome editing in Saccharomyces cerevisiae. Using FnCas12a, this work demonstrates that transforming short, linear DNA fragments encoding gRNAs in yeast strains expressing T7RNAP promotes highly efficient single and duplex DNA editing. These DNA fragments can be custom ordered, which makes this approach highly suitable for high-throughput strain construction. This work expands the CRISPR toolbox for large-scale strain construction programs in S. cerevisiae and promises to be relevant for other less genetically accessible yeast species.
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Affiliation(s)
- Paola Randazzo
- Department of Biotechnology, Delft University of Biotechnology, Delft, Netherlands
| | - Nicole Xanthe Bennis
- Department of Biotechnology, Delft University of Biotechnology, Delft, Netherlands
| | - Jean-Marc Daran
- Department of Biotechnology, Delft University of Biotechnology, Delft, Netherlands
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7
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Pietschmann M, Tempel G, Halladjian M, Krogh N, Nielsen H. Use of a Lariat Capping Ribozyme to Study Cap Function In Vivo. Methods Mol Biol 2021; 2167:271-285. [PMID: 32712925 DOI: 10.1007/978-1-0716-0716-9_15] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
A lariat cap is a naturally occurring substitute of a conventional mRNA cap and is found in a particular genomic setting in a few eukaryotic microorganisms. It is installed by the lariat capping ribozyme acting in cis. In principle, any RNA molecule in any organism can be equipped with a lariat cap in vivo when expressed downstream of a lariat capping ribozyme. Lariat capping is thus a versatile tool for studying the importance of the 5' end structure of RNA molecules. In this chapter, we present protocols to validate the presence of the lariat cap and measure the efficiency of in vivo cleavage by the lariat capping ribozyme.
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Affiliation(s)
- Max Pietschmann
- Department of Cellular and Molecular Medicine, University of Copenhagen, Copenhagen, Denmark
| | - Gregor Tempel
- Department of Cellular and Molecular Medicine, University of Copenhagen, Copenhagen, Denmark
| | - Maral Halladjian
- Department of Cellular and Molecular Medicine, University of Copenhagen, Copenhagen, Denmark
| | - Nicolai Krogh
- Department of Cellular and Molecular Medicine, University of Copenhagen, Copenhagen, Denmark
| | - Henrik Nielsen
- Department of Cellular and Molecular Medicine, University of Copenhagen, Copenhagen, Denmark.
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8
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Shanaa OA, Rumyantsev A, Sambuk E, Padkina M. In Vivo Production of RNA Aptamers and Nanoparticles: Problems and Prospects. Molecules 2021; 26:molecules26051422. [PMID: 33800717 PMCID: PMC7961669 DOI: 10.3390/molecules26051422] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Revised: 03/04/2021] [Accepted: 03/04/2021] [Indexed: 12/26/2022] Open
Abstract
RNA aptamers are becoming increasingly attractive due to their superior properties. This review discusses the early stages of aptamer research, the main developments in this area, and the latest technologies being developed. The review also highlights the advantages of RNA aptamers in comparison to antibodies, considering the great potential of RNA aptamers and their applications in the near future. In addition, it is shown how RNA aptamers can form endless 3-D structures, giving rise to various structural and functional possibilities. Special attention is paid to the Mango, Spinach and Broccoli fluorescent RNA aptamers, and the advantages of split RNA aptamers are discussed. The review focuses on the importance of creating a platform for the synthesis of RNA nanoparticles in vivo and examines yeast, namely Saccharomyces cerevisiae, as a potential model organism for the production of RNA nanoparticles on a large scale.
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Affiliation(s)
- Ousama Al Shanaa
- Department of Genetics and Biotechnology, Saint Petersburg State University, 199034 Saint Petersburg, Russia; (A.R.); (E.S.)
- Atomic Energy Commission of Syria, Damascus P.O.B 6091, Syria
- Correspondence: (O.A.S.); (M.P.); Tel.: +7-812-328-2822 (O.A.S.); +7-812-327-9827 (M.P.)
| | - Andrey Rumyantsev
- Department of Genetics and Biotechnology, Saint Petersburg State University, 199034 Saint Petersburg, Russia; (A.R.); (E.S.)
| | - Elena Sambuk
- Department of Genetics and Biotechnology, Saint Petersburg State University, 199034 Saint Petersburg, Russia; (A.R.); (E.S.)
| | - Marina Padkina
- Department of Genetics and Biotechnology, Saint Petersburg State University, 199034 Saint Petersburg, Russia; (A.R.); (E.S.)
- Correspondence: (O.A.S.); (M.P.); Tel.: +7-812-328-2822 (O.A.S.); +7-812-327-9827 (M.P.)
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9
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Role of promoters in regulating alternative splicing. Gene 2021; 782:145523. [PMID: 33667606 DOI: 10.1016/j.gene.2021.145523] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2020] [Revised: 12/31/2020] [Accepted: 02/09/2021] [Indexed: 01/19/2023]
Abstract
Alternative splicing (AS) plays a critical role in enhancing proteome complexity in higher eukaryotes. Almost all the multi intron-containing genes undergo AS in humans. Splicing mainly occurs co-transcriptionally, where RNA polymerase II (RNA pol II) plays a crucial role in coordinating transcription and pre-mRNA splicing. Aberrant AS leads to non-functional proteins causative in various pathophysiological conditions such as cancers, neurodegenerative diseases, and muscular dystrophies. Transcription and pre-mRNA splicing are deeply interconnected and can influence each other's functions. Several studies evinced that specific promoters employed by RNA pol II dictate the RNA processing decisions. Promoter-specific recruitment of certain transcriptional factors or transcriptional coactivators influences splicing, and the extent to which these factors affect splicing has not been discussed in detail. Here, in this review, various DNA-binding proteins and their influence on promoter-specific AS are extensively discussed. Besides, this review highlights how the promoter-specific epigenetic changes might regulate AS.
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10
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Costello A, Badran AH. Synthetic Biological Circuits within an Orthogonal Central Dogma. Trends Biotechnol 2021; 39:59-71. [PMID: 32586633 PMCID: PMC7746572 DOI: 10.1016/j.tibtech.2020.05.013] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2020] [Revised: 05/28/2020] [Accepted: 05/29/2020] [Indexed: 12/16/2022]
Abstract
Synthetic biology strives to reliably control cellular behavior, typically in the form of user-designed interactions of biological components to produce a predetermined output. Engineered circuit components are frequently derived from natural sources and are therefore often hampered by inadvertent interactions with host machinery, most notably within the host central dogma. Reliable and predictable gene circuits require the targeted reduction or elimination of these undesirable interactions to mitigate negative consequences on host fitness and develop context-independent bioactivities. Here, we review recent advances in biological orthogonalization, namely the insulation of researcher-dictated bioactivities from host processes, with a focus on systematic developments that may culminate in the creation of an orthogonal central dogma and novel cellular functions.
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Affiliation(s)
- Alan Costello
- Broad Institute of MIT and Harvard, Cambridge, MA, 02142, USA
| | - Ahmed H Badran
- Broad Institute of MIT and Harvard, Cambridge, MA, 02142, USA.
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11
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Álvarez B, Mencía M, de Lorenzo V, Fernández LÁ. In vivo diversification of target genomic sites using processive base deaminase fusions blocked by dCas9. Nat Commun 2020; 11:6436. [PMID: 33353963 PMCID: PMC7755918 DOI: 10.1038/s41467-020-20230-z] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2019] [Accepted: 11/20/2020] [Indexed: 02/07/2023] Open
Abstract
In vivo mutagenesis systems accelerate directed protein evolution but often show restricted capabilities and deleterious off-site mutations on cells. To overcome these limitations, here we report an in vivo platform to diversify specific DNA segments based on protein fusions between various base deaminases (BD) and the T7 RNA polymerase (T7RNAP) that recognizes a cognate promoter oriented towards the target sequence. Transcriptional elongation of these fusions generates transitions C to T or A to G on both DNA strands and in long DNA segments. To delimit the boundaries of the diversified DNA, the catalytically dead Cas9 (dCas9) is tethered with custom-designed crRNAs as a "roadblock" for BD-T7RNAP elongation. Using this T7-targeted dCas9-limited in vivo mutagenesis (T7-DIVA) system, rapid molecular evolution of the antibiotic resistance gene TEM-1 is achieved. While the efficiency is demonstrated in E. coli, the system can be adapted to a variety of bacterial and eukaryotic hosts.
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Affiliation(s)
- Beatriz Álvarez
- Department of Microbial Biotechnology, Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas (CNB-CSIC), Darwin 3, Campus UAM Cantoblanco, 28049, Madrid, Spain
| | - Mario Mencía
- Centro de Biología Molecular "Severo Ochoa" (Consejo Superior de Investigaciones Científicas - Universidad Autónoma de Madrid), Nicolas Cabrera 1, Campus UAM Cantoblanco, 28049, Madrid, Spain
| | - Víctor de Lorenzo
- Systems Biology Program, Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas (CNB-CSIC), Darwin 3, Campus UAM Cantoblanco, 28049, Madrid, Spain
| | - Luis Ángel Fernández
- Department of Microbial Biotechnology, Centro Nacional de Biotecnología, Consejo Superior de Investigaciones Científicas (CNB-CSIC), Darwin 3, Campus UAM Cantoblanco, 28049, Madrid, Spain.
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12
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Cassart C, Yague-Sanz C, Bauer F, Ponsard P, Stubbe FX, Migeot V, Wery M, Morillon A, Palladino F, Robert V, Hermand D. RNA polymerase II CTD S2P is dispensable for embryogenesis but mediates exit from developmental diapause in C. elegans. SCIENCE ADVANCES 2020; 6:6/50/eabc1450. [PMID: 33298437 PMCID: PMC7725455 DOI: 10.1126/sciadv.abc1450] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/08/2020] [Accepted: 10/21/2020] [Indexed: 06/12/2023]
Abstract
Serine 2 phosphorylation (S2P) within the CTD of RNA polymerase II is considered a Cdk9/Cdk12-dependent mark required for 3'-end processing. However, the relevance of CTD S2P in metazoan development is unknown. We show that cdk-12 lesions or a full-length CTD S2A substitution results in an identical phenotype in Caenorhabditis elegans Embryogenesis occurs in the complete absence of S2P, but the hatched larvae arrest development, mimicking the diapause induced when hatching occurs in the absence of food. Genome-wide analyses indicate that when CTD S2P is inhibited, only a subset of growth-related genes is not properly expressed. These genes correspond to SL2 trans-spliced mRNAs located in position 2 and over within operons. We show that CDK-12 is required for maximal occupancy of cleavage stimulatory factor necessary for SL2 trans-splicing. We propose that CTD S2P functions as a gene-specific signaling mark ensuring the nutritional control of the C. elegans developmental program.
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Affiliation(s)
- C Cassart
- URPHYM-GEMO, The University of Namur, rue de Bruxelles, 61, Namur 5000 Belgium
| | - C Yague-Sanz
- URPHYM-GEMO, The University of Namur, rue de Bruxelles, 61, Namur 5000 Belgium
| | - F Bauer
- URPHYM-GEMO, The University of Namur, rue de Bruxelles, 61, Namur 5000 Belgium
| | - P Ponsard
- URPHYM-GEMO, The University of Namur, rue de Bruxelles, 61, Namur 5000 Belgium
| | - F X Stubbe
- URPHYM-GEMO, The University of Namur, rue de Bruxelles, 61, Namur 5000 Belgium
| | - V Migeot
- URPHYM-GEMO, The University of Namur, rue de Bruxelles, 61, Namur 5000 Belgium
| | - M Wery
- ncRNA, epigenetic and genome fluidity, Institut Curie, PSL Research University, CNRS UMR 3244, Université Pierre et Marie Curie, Paris, France
| | - A Morillon
- ncRNA, epigenetic and genome fluidity, Institut Curie, PSL Research University, CNRS UMR 3244, Université Pierre et Marie Curie, Paris, France
| | - F Palladino
- Laboratory of Biology and Modeling of the Cell, UMR5239 CNRS/Ecole Normale Supérieure de Lyon, INSERM U1210, UMS 3444 Biosciences Lyon Gerland, Université de Lyon, Lyon, France
| | - V Robert
- Laboratory of Biology and Modeling of the Cell, UMR5239 CNRS/Ecole Normale Supérieure de Lyon, INSERM U1210, UMS 3444 Biosciences Lyon Gerland, Université de Lyon, Lyon, France
| | - D Hermand
- URPHYM-GEMO, The University of Namur, rue de Bruxelles, 61, Namur 5000 Belgium.
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13
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Ahmed I, Karedath T, Al-Dasim FM, Malek JA. Identification of human genetic variants controlling circular RNA expression. RNA (NEW YORK, N.Y.) 2019; 25:1765-1778. [PMID: 31519742 PMCID: PMC6859849 DOI: 10.1261/rna.071654.119] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2019] [Accepted: 09/11/2019] [Indexed: 06/01/2023]
Abstract
Circular RNAs (circRNAs) are abundant in eukaryotic transcriptomes and have been linked to various human disorders. However, understanding genetic control of circular RNA expression is in the early stages. Here we present the first integrated analysis of circRNAs and genome sequence variation from lymphoblastoid cell lines of the 1000 Genomes Project. We identified thousands of circRNAs in the RNA-seq data and show their association with local single-nucleotide polymorphic sites, referred to as circQTLs, which influence the circRNA transcript abundance. Strikingly, we found that circQTLs exist independently of eQTLs with most circQTLs having no effect on mRNA expression. Only a fraction of the polymorphic sites are shared and linked to both circRNA and mRNA expression with mostly similar effects on circular and linear RNA. A shared intronic QTL, rs55928920, of HMSD gene drives the circular and linear expression in opposite directions, potentially modulating circRNA levels at the expense of mRNA. Finally, circQTLs and eQTLs are largely independent and exist in separate linkage disequilibrium (LD) blocks with circQTLs highly enriched for functional genomic elements and regulatory regions. This study reveals a previously uncharacterized role of DNA sequence variation in human circular RNA regulation.
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Affiliation(s)
- Ikhlak Ahmed
- Department of Genetic Medicine, Weill Cornell Medicine-Qatar, Doha, Qatar
- Biomedical Informatics, Sidra Medicine, Doha, Qatar
| | - Thasni Karedath
- Department of Genetic Medicine, Weill Cornell Medicine-Qatar, Doha, Qatar
| | - Fatima M Al-Dasim
- Department of Genetic Medicine, Weill Cornell Medicine-Qatar, Doha, Qatar
| | - Joel A Malek
- Department of Genetic Medicine, Weill Cornell Medicine-Qatar, Doha, Qatar
- Genomics Core, Weill Cornell Medicine-Qatar, Doha, Qatar
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14
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Decoene T, De Maeseneire SL, De Mey M. Modulating transcription through development of semi-synthetic yeast core promoters. PLoS One 2019; 14:e0224476. [PMID: 31689317 PMCID: PMC6830820 DOI: 10.1371/journal.pone.0224476] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2019] [Accepted: 10/15/2019] [Indexed: 01/07/2023] Open
Abstract
Altering gene expression regulation by promoter engineering is a very effective way to fine-tune heterologous pathways in eukaryotic hosts. Typically, pathway building approaches in yeast still use a limited set of long, native promoters. With the today’s introduction of longer and more complex pathways, an expansion of this synthetic biology toolbox is necessary. In this study we elucidated the core promoter structure of the well-characterized yeast TEF1 promoter and determined the minimal length needed for sufficient protein expression. Furthermore, this minimal core promoter sequence was used for the creation of a promoter library covering different expression strengths. This resulted in a group of short, 69 bp promoters with an 8.0-fold expression range. One exemplar had a two and four times higher expression compared to the native CYC1 and ADH1 promoter, respectively. Additionally, as it was described that the protein expression range could be broadened by upstream activating sequences (UASs), we integrated earlier described single and multiple short, synthetic UASs in front of the strongest yeast core promoter. This approach resulted to further variation in protein expression and an overall promoter library spanning a 20-fold activity range and covering a length from 69 bp to maximally 129 bp. Furthermore, the robustness of this library was assessed on three alternative carbon sources besides glucose. As such, the suitability of short yeast core promoters for metabolic engineering applications on different media, either in an individual context or combined with UAS elements, was demonstrated.
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Affiliation(s)
- Thomas Decoene
- Centre for Synthetic Biology (CSB), Ghent University, Ghent, Belgium
| | - Sofie L. De Maeseneire
- Centre for Industrial Biotechnology and Biocatalysis (InBio.be), Ghent University, Coupure links, Ghent, Belgium
| | - Marjan De Mey
- Centre for Synthetic Biology (CSB), Ghent University, Ghent, Belgium
- * E-mail:
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15
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Jaïs PH, Decroly E, Jacquet E, Le Boulch M, Jaïs A, Jean-Jean O, Eaton H, Ponien P, Verdier F, Canard B, Goncalves S, Chiron S, Le Gall M, Mayeux P, Shmulevitz M. C3P3-G1: first generation of a eukaryotic artificial cytoplasmic expression system. Nucleic Acids Res 2019; 47:2681-2698. [PMID: 30726994 PMCID: PMC6412113 DOI: 10.1093/nar/gkz069] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2018] [Revised: 12/03/2018] [Accepted: 01/25/2019] [Indexed: 12/25/2022] Open
Abstract
Most eukaryotic expression systems make use of host-cell nuclear transcriptional and post-transcriptional machineries. Here, we present the first generation of the chimeric cytoplasmic capping-prone phage polymerase (C3P3-G1) expression system developed by biological engineering, which generates capped and polyadenylated transcripts in host-cell cytoplasm by means of two components. First, an artificial single-unit chimeric enzyme made by fusing an mRNA capping enzyme and a DNA-dependent RNA polymerase. Second, specific DNA templates designed to operate with the C3P3-G1 enzyme, which encode for the transcripts and their artificial polyadenylation. This system, which can potentially be adapted to any in cellulo or in vivo eukaryotic expression applications, was optimized for transient expression in mammalian cells. C3P3-G1 shows promising results for protein production in Chinese Hamster Ovary (CHO-K1) cells. This work also provides avenues for enhancing the performances for next generation C3P3 systems.
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Affiliation(s)
- Philippe H Jaïs
- Eukarÿs SAS, Génopole Campus 3, 4 rue Pierre Fontaine, 91058 Evry Cedex, France
| | - Etienne Decroly
- Architecture et Fonction des Macromolécules Biologiques (AFMB) UMR 7257 CNRS/AMU, 163 Avenue de Luminy, 13288 Marseille Cedex 9, France
| | - Eric Jacquet
- Institut de Chimie des Substances Naturelles, CNRS UPR2301, Université Paris-Saclay, Avenue de la Terrasse, 91198 Gif-sur-Yvette, France
| | - Marine Le Boulch
- Eukarÿs SAS, Génopole Campus 3, 4 rue Pierre Fontaine, 91058 Evry Cedex, France
| | - Aurélien Jaïs
- Eukarÿs SAS, Génopole Campus 3, 4 rue Pierre Fontaine, 91058 Evry Cedex, France
| | - Olivier Jean-Jean
- Sorbonne Université, CNRS-UMR8256, Biological Adaptation and Ageing, Institut de Biologie Paris Seine (B2A-IBPS), F-75252 Paris, France
| | - Heather Eaton
- Medical Microbiology and Immunology, University of Alberta, 6-142J Katz Group Centre for Pharmacy and Health Research, 114 Street NW, Edmonton, Alberta T6G 2E1, Canada
| | - Prishila Ponien
- Institut de Chimie des Substances Naturelles, CNRS UPR2301, Université Paris-Saclay, Avenue de la Terrasse, 91198 Gif-sur-Yvette, France
| | - Fréderique Verdier
- INSERM Unit 1016, Institut Cochin, Bâtiment Gustave Roussy, 27 rue du faubourg Saint-Jacques, 75014 Paris, France
| | - Bruno Canard
- Architecture et Fonction des Macromolécules Biologiques (AFMB) UMR 7257 CNRS/AMU, 163 Avenue de Luminy, 13288 Marseille Cedex 9, France
| | - Sergio Goncalves
- Eukarÿs SAS, Génopole Campus 3, 4 rue Pierre Fontaine, 91058 Evry Cedex, France
| | - Stéphane Chiron
- Eukarÿs SAS, Génopole Campus 3, 4 rue Pierre Fontaine, 91058 Evry Cedex, France
| | - Maude Le Gall
- Gastrointestinal and Metabolic Dysfunctions in Nutritional Pathologies, INSERM UMRS1149, 16 rue Henri Huchard, 75890 Paris Cedex 18, France
| | - Patrick Mayeux
- INSERM Unit 1016, Institut Cochin, Bâtiment Gustave Roussy, 27 rue du faubourg Saint-Jacques, 75014 Paris, France
| | - Maya Shmulevitz
- Medical Microbiology and Immunology, University of Alberta, 6-142J Katz Group Centre for Pharmacy and Health Research, 114 Street NW, Edmonton, Alberta T6G 2E1, Canada
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16
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Moore CL, Papa LJ, Shoulders MD. A Processive Protein Chimera Introduces Mutations across Defined DNA Regions In Vivo. J Am Chem Soc 2018; 140:11560-11564. [PMID: 29991261 PMCID: PMC6166643 DOI: 10.1021/jacs.8b04001] [Citation(s) in RCA: 64] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Laboratory time scale evolution in vivo relies on the generation of large, mutationally diverse gene libraries to rapidly explore biomolecule sequence landscapes. Traditional global mutagenesis methods are problematic because they introduce many off-target mutations that are often lethal and can engender false positives. We report the development and application of the MutaT7 chimera, a potent and highly targeted in vivo mutagenesis agent. MutaT7 utilizes a DNA-damaging cytidine deaminase fused to a processive RNA polymerase to continuously direct mutations to specific, well-defined DNA regions of any relevant length. MutaT7 thus provides a mechanism for in vivo targeted mutagenesis across multi-kb DNA sequences. MutaT7 should prove useful in diverse organisms, opening the door to new types of in vivo evolution experiments.
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Affiliation(s)
- Christopher L Moore
- Department of Chemistry , Massachusetts Institute of Technology , 77 Massachusetts Avenue , Cambridge , Massachusetts 02139 , United States
| | - Louis J Papa
- Department of Chemistry , Massachusetts Institute of Technology , 77 Massachusetts Avenue , Cambridge , Massachusetts 02139 , United States
| | - Matthew D Shoulders
- Department of Chemistry , Massachusetts Institute of Technology , 77 Massachusetts Avenue , Cambridge , Massachusetts 02139 , United States
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17
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Sheen H, White KA. Expression of T7-based constructs in tobacco cells. Biochem Biophys Res Commun 2018; 499:196-201. [PMID: 29555475 DOI: 10.1016/j.bbrc.2018.03.123] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2018] [Accepted: 03/15/2018] [Indexed: 10/17/2022]
Abstract
Bacteriophage T7 promoter and RNA polymerase (T7-Pol) are widely used for recombinant protein expression in bacteria. In plants, there exists conflicting results regarding the efficacy of protein expression from T7-Pol-derived mRNAs. To reconcile these contradictory observations, the expression of green fluorescent protein (GFP) from T7 constructs was evaluated in tobacco protoplasts. T7 constructs transcribed by a nuclearly targeted T7-Pol did not express GFP in plant protoplasts, however T7-Pol lacking a nuclear targeting signal was able to translate cytosolically transcribed mRNAs, but only if the messages contained a viral translation enhancer. GFP expression was further evaluated at the plant level by using agroinfiltration-mediated transient expression system. Unlike for cytosolic expression, nuclear T7 transcripts containing a viral translation enhancer element did not express GFP, and modifications designed to stabilize and facilitate export of T7 transcripts to the cytosol did not improve the expression. We conclude that expression of nuclear T7 constructs is not feasible in tobacco cells, but cytosolic transcription provides an alternative means to over-express RNAs directly in the cytosol.
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Affiliation(s)
- Hyukho Sheen
- Department of Biology, York University, 4700 Keele Street, Toronto, Ontario, M3J 1P3, Canada.
| | - K Andrew White
- Department of Biology, York University, 4700 Keele Street, Toronto, Ontario, M3J 1P3, Canada.
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18
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Morse NJ, Wagner JM, Reed KB, Gopal MR, Lauffer LH, Alper HS. T7 Polymerase Expression of Guide RNAs in vivo Allows Exportable CRISPR-Cas9 Editing in Multiple Yeast Hosts. ACS Synth Biol 2018; 7:1075-1084. [PMID: 29565571 DOI: 10.1021/acssynbio.7b00461] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Efficient guide RNA expression often limits CRISPR-Cas9 implementation in new hosts. To address this limitation in fungal systems, we demonstrate the utility of a T7 polymerase system to effectively express sgRNAs. Initially, we developed a methodology in Saccharomyces cerevisiae using a modified version of the T7 P266L mutant polymerase with an SV40 nuclear localization signal to allow guide RNA expression immediately downstream of a T7 promoter. To improve targeting efficiency, guide RNA design was found to be tolerant to three mismatches or up to three additional bases appended to the 5' end. The addition of three guanines to a T7-based guide RNA improved guide RNA expression 80-fold and achieved transcriptional output similar to the strong Pol III snr52 promoter. Resulting gene editing and dCas9-guided gene regulation with a T7-based guide RNA was on par with the commonly used snr52 system in S. cerevisiae. Finally, 96% and 60% genome editing efficiencies were achieved in Kluyveromyces lactis and Yarrowia lipolytica respectively with minimal optimization of this system. Thus, T7-based expression of sgRNAs offers an orthogonal method for implementing CRISPR systems in fungal systems.
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Affiliation(s)
- Nicholas J Morse
- McKetta Department of Chemical Engineering , The University of Texas at Austin , 200 E Dean Keeton Street Stop C0400 , Austin , Texas 78712 , United States
| | - James M Wagner
- McKetta Department of Chemical Engineering , The University of Texas at Austin , 200 E Dean Keeton Street Stop C0400 , Austin , Texas 78712 , United States
| | - Kevin B Reed
- McKetta Department of Chemical Engineering , The University of Texas at Austin , 200 E Dean Keeton Street Stop C0400 , Austin , Texas 78712 , United States
| | - Madan R Gopal
- McKetta Department of Chemical Engineering , The University of Texas at Austin , 200 E Dean Keeton Street Stop C0400 , Austin , Texas 78712 , United States
| | - Lars H Lauffer
- McKetta Department of Chemical Engineering , The University of Texas at Austin , 200 E Dean Keeton Street Stop C0400 , Austin , Texas 78712 , United States
| | - Hal S Alper
- McKetta Department of Chemical Engineering , The University of Texas at Austin , 200 E Dean Keeton Street Stop C0400 , Austin , Texas 78712 , United States
- Institute for Cellular and Molecular Biology , The University of Texas at Austin , 2500 Speedway Avenue , Austin , Texas 78712 , United States
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19
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Rambout X, Dequiedt F, Maquat LE. Beyond Transcription: Roles of Transcription Factors in Pre-mRNA Splicing. Chem Rev 2017; 118:4339-4364. [PMID: 29251915 DOI: 10.1021/acs.chemrev.7b00470] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Whereas individual steps of protein-coding gene expression in eukaryotes can be studied in isolation in vitro, it has become clear that these steps are intimately connected within cells. Connections not only ensure quality control but also fine-tune the gene expression process, which must adapt to environmental changes while remaining robust. In this review, we systematically present proven and potential mechanisms by which sequence-specific DNA-binding transcription factors can alter gene expression beyond transcription initiation and regulate pre-mRNA splicing, and thereby mRNA isoform production, by (i) influencing transcription elongation rates, (ii) binding to pre-mRNA to recruit splicing factors, and/or (iii) blocking the association of splicing factors with pre-mRNA. We propose various mechanistic models throughout the review, in some cases without explicit supportive evidence, in hopes of providing fertile ground for future studies.
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20
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Krogh N, Pietschmann M, Schmid M, Jensen TH, Nielsen H. Lariat capping as a tool to manipulate the 5' end of individual yeast mRNA species in vivo. RNA (NEW YORK, N.Y.) 2017; 23:683-695. [PMID: 28159804 PMCID: PMC5393178 DOI: 10.1261/rna.059337.116] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/25/2016] [Accepted: 01/31/2017] [Indexed: 06/06/2023]
Abstract
The 5' cap structure of eukaryotic mRNA is critical for its processing, transport, translation, and stability. The many functions of the cap and the fact that most, if not all, mRNA carries the same type of cap makes it difficult to analyze cap function in vivo at individual steps of gene expression. We have used the lariat capping ribozyme (LCrz) from the myxomycete Didymium to replace the mRNA m7G cap of a single reporter mRNA species with a tiny lariat in which the first and the third nucleotide are joined by a 2', 5' phosphodiester bond. We show that the ribozyme functions in vivo in the budding yeast Saccharomyces cerevisiae presumably without cofactors and that lariat capping occurs cotranscriptionally. The lariat-capped reporter mRNA is efficiently exported to the cytoplasm where it is found to be oligoadenylated and evenly distributed. Both the oligoadenylated form and a lariat-capped mRNA with a templated poly(A) tail translates poorly, underlining the critical importance of the m7G cap in translation. Finally, the lariat-capped RNA exhibits a threefold longer half-life compared to its m7G-capped counterpart, consistent with a key role for the m7G cap in mRNA turnover. Our study emphasizes important activities of the m7G cap and suggests new utilities of lariat capping as a molecular tool in vivo.
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Affiliation(s)
- Nicolai Krogh
- Department of Cellular and Molecular Medicine, University of Copenhagen, DK-2200 Copenhagen N, Denmark
| | - Max Pietschmann
- Department of Cellular and Molecular Medicine, University of Copenhagen, DK-2200 Copenhagen N, Denmark
| | - Manfred Schmid
- Department of Molecular Biology and Genetics, Aarhus University, 8000 Aarhus C, Denmark
| | - Torben Heick Jensen
- Department of Molecular Biology and Genetics, Aarhus University, 8000 Aarhus C, Denmark
| | - Henrik Nielsen
- Department of Cellular and Molecular Medicine, University of Copenhagen, DK-2200 Copenhagen N, Denmark
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21
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Björk P, Wieslander L. Integration of mRNP formation and export. Cell Mol Life Sci 2017; 74:2875-2897. [PMID: 28314893 PMCID: PMC5501912 DOI: 10.1007/s00018-017-2503-3] [Citation(s) in RCA: 53] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2016] [Revised: 03/06/2017] [Accepted: 03/07/2017] [Indexed: 12/13/2022]
Abstract
Expression of protein-coding genes in eukaryotes relies on the coordinated action of many sophisticated molecular machineries. Transcription produces precursor mRNAs (pre-mRNAs) and the active gene provides an environment in which the pre-mRNAs are processed, folded, and assembled into RNA–protein (RNP) complexes. The dynamic pre-mRNPs incorporate the growing transcript, proteins, and the processing machineries, as well as the specific protein marks left after processing that are essential for export and the cytoplasmic fate of the mRNPs. After release from the gene, the mRNPs move by diffusion within the interchromatin compartment, making up pools of mRNPs. Here, splicing and polyadenylation can be completed and the mRNPs recruit the major export receptor NXF1. Export competent mRNPs interact with the nuclear pore complex, leading to export, concomitant with compositional and conformational changes of the mRNPs. We summarize the integrated nuclear processes involved in the formation and export of mRNPs.
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Affiliation(s)
- Petra Björk
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, 106 91 Stockholm, Sweden
| | - Lars Wieslander
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, 106 91 Stockholm, Sweden
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22
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Ocampo-Hafalla M, Muñoz S, Samora CP, Uhlmann F. Evidence for cohesin sliding along budding yeast chromosomes. Open Biol 2016; 6:150178. [PMID: 27278645 PMCID: PMC4929932 DOI: 10.1098/rsob.150178] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2015] [Accepted: 05/13/2016] [Indexed: 11/12/2022] Open
Abstract
The ring-shaped cohesin complex is thought to topologically hold sister chromatids together from their synthesis in S phase until chromosome segregation in mitosis. How cohesin stably binds to chromosomes for extended periods, without impeding other chromosomal processes that also require access to the DNA, is poorly understood. Budding yeast cohesin is loaded onto DNA by the Scc2-Scc4 cohesin loader at centromeres and promoters of active genes, from where cohesin translocates to more permanent places of residence at transcription termination sites. Here we show that, at the GAL2 and MET17 loci, pre-existing cohesin is pushed downstream along the DNA in response to transcriptional gene activation, apparently without need for intermittent dissociation or reloading. We observe translocation intermediates and find that the distribution of most chromosomal cohesin is shaped by transcription. Our observations support a model in which cohesin is able to slide laterally along chromosomes while maintaining topological contact with DNA. In this way, stable cohesin binding to DNA and enduring sister chromatid cohesion become compatible with simultaneous underlying chromosomal activities, including but maybe not limited to transcription.
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Affiliation(s)
- Maria Ocampo-Hafalla
- The Francis Crick Institute, Lincoln's Inn Fields Laboratory, 44 Lincoln's Inn Fields, London WC2A 3LY, UK
| | - Sofía Muñoz
- The Francis Crick Institute, Lincoln's Inn Fields Laboratory, 44 Lincoln's Inn Fields, London WC2A 3LY, UK
| | - Catarina P Samora
- The Francis Crick Institute, Lincoln's Inn Fields Laboratory, 44 Lincoln's Inn Fields, London WC2A 3LY, UK
| | - Frank Uhlmann
- The Francis Crick Institute, Lincoln's Inn Fields Laboratory, 44 Lincoln's Inn Fields, London WC2A 3LY, UK
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23
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Naftelberg S, Schor IE, Ast G, Kornblihtt AR. Regulation of alternative splicing through coupling with transcription and chromatin structure. Annu Rev Biochem 2015; 84:165-98. [PMID: 26034889 DOI: 10.1146/annurev-biochem-060614-034242] [Citation(s) in RCA: 314] [Impact Index Per Article: 34.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Alternative precursor messenger RNA (pre-mRNA) splicing plays a pivotal role in the flow of genetic information from DNA to proteins by expanding the coding capacity of genomes. Regulation of alternative splicing is as important as regulation of transcription to determine cell- and tissue-specific features, normal cell functioning, and responses of eukaryotic cells to external cues. Its importance is confirmed by the evolutionary conservation and diversification of alternative splicing and the fact that its deregulation causes hereditary disease and cancer. This review discusses the multiple layers of cotranscriptional regulation of alternative splicing in which chromatin structure, DNA methylation, histone marks, and nucleosome positioning play a fundamental role in providing a dynamic scaffold for interactions between the splicing and transcription machineries. We focus on evidence for how the kinetics of RNA polymerase II (RNAPII) elongation and the recruitment of splicing factors and adaptor proteins to chromatin components act in coordination to regulate alternative splicing.
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Affiliation(s)
- Shiran Naftelberg
- Sackler Medical School, Tel Aviv University, Tel Aviv 69978, Israel;
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24
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Steakley DL, Rine J. On the Mechanism of Gene Silencing in Saccharomyces cerevisiae. G3 (BETHESDA, MD.) 2015; 5:1751-63. [PMID: 26082137 PMCID: PMC4528331 DOI: 10.1534/g3.115.018515] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/11/2015] [Accepted: 06/15/2015] [Indexed: 11/18/2022]
Abstract
Multiple mechanisms have been proposed for gene silencing in Saccharomyces cerevisiae, ranging from steric occlusion of DNA binding proteins from their recognition sequences in silenced chromatin to a specific block in the formation of the preinitiation complex to a block in transcriptional elongation. This study provided strong support for the steric occlusion mechanism by the discovery that RNA polymerase of bacteriophage T7 could be substantially blocked from transcribing from its cognate promoter when embedded in silenced chromatin. Moreover, unlike previous suggestions, we found no evidence for stalled RNA polymerase II within silenced chromatin. The effectiveness of the Sir protein-based silencing mechanism to block transcription activated by Gal4 at promoters in the domain of silenced chromatin was marginal, yet it improved when tested against mutant forms of the Gal4 protein, highlighting a role for specific activators in their sensitivity to gene silencing.
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Affiliation(s)
- David Lee Steakley
- Department of Molecular and Cell Biology, California Institute of Quantitative Biosciences, Stanley Hall, University of California Berkeley, Berkeley, California 94720
| | - Jasper Rine
- Department of Molecular and Cell Biology, California Institute of Quantitative Biosciences, Stanley Hall, University of California Berkeley, Berkeley, California 94720
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25
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Dušková E, Hnilicová J, Staněk D. CRE promoter sites modulate alternative splicing via p300-mediated histone acetylation. RNA Biol 2014; 11:865-74. [PMID: 25019513 DOI: 10.4161/rna.29441] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Histone acetylation modulates alternative splicing of several hundred genes. Here, we tested the role of the histone acetyltransferase p300 in alternative splicing and showed that knockdown of p300 promotes inclusion of the fibronectin (FN1) alternative EDB exon. p300 associates with CRE sites in the promoter via the CREB transcription factor. We created mini-gene reporters driven by an artificial promoter containing CRE sites. Both deletion and mutation of the CRE site affected EDB alternative splicing in the same manner as p300 knockdown. Next we showed that p300 controls histone H4 acetylation along the FN1 gene. Consistently, p300 depletion and CRE deletion/mutation both reduced histone H4 acetylation on mini-gene reporters. Finally, we provide evidence that the effect of CRE inactivation on H4 acetylation and alternative splicing is counteracted by the inhibition of histone deacetylases. Together, these data suggest that histone acetylation could be one of the mechanisms how promoter and promoter binding proteins influence alternative splicing.
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Affiliation(s)
- Eva Dušková
- Department of RNA Biology, Institute of Molecular Genetics, Academy of Sciences of the Czech Republic, Prague, Czech Republic; Faculty of Science, Charles University in Prague, Prague, Czech Republic
| | - Jarmila Hnilicová
- Institute of Microbiology, Academy of Sciences of the Czech Republic, Prague, Czech Republic
| | - David Staněk
- Department of RNA Biology, Institute of Molecular Genetics, Academy of Sciences of the Czech Republic, Prague, Czech Republic
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Abstract
In the past several years, the relationship between chromatin structure and mRNA processing has been the source of significant investigation across diverse disciplines. Central to these efforts was an unanticipated nonrandom distribution of chromatin marks across transcribed regions of protein-coding genes. In addition to the presence of specific histone modifications at the 5' and 3' ends of genes, exonic DNA was demonstrated to present a distinct chromatin landscape relative to intronic DNA. As splicing in higher eukaryotes predominantly occurs co-transcriptionally, these studies raised the possibility that chromatin modifications may aid the spliceosome in the detection of exons amidst vast stretches of noncoding intronic sequences. Recent investigations have supported a direct role for chromatin in splicing regulation and have suggested an intriguing role for splicing in the establishment of chromatin modifications. Here we will summarize an accumulating body of data that begins to reveal extensive coupling between chromatin structure and pre-mRNA splicing.
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Affiliation(s)
- Nazmul Haque
- Laboratory of Ribonucleoprotein Biochemistry, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, USA
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27
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Hobl B, Hock B, Schneck S, Fischer R, Mack M. Bacteriophage T7 RNA polymerase-based expression in Pichia pastoris. Protein Expr Purif 2013; 92:100-4. [PMID: 24056257 DOI: 10.1016/j.pep.2013.09.004] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2013] [Revised: 09/03/2013] [Accepted: 09/06/2013] [Indexed: 11/16/2022]
Abstract
A novel Pichia pastoris expression vector (pEZT7) for the production of recombinant proteins employing prokaryotic bacteriophage T7 RNA polymerase (T7 RNAP) (EC 2.7.7.6) and the corresponding promoter pT7 was constructed. The gene for T7 RNAP was stably introduced into the P. pastoris chromosome 2 under control of the (endogenous) constitutive P. pastoris glyceraldehyde-3-phosphate dehydrogenase (GAP) promoter (pGAP). The gene product T7 RNAP was engineered to contain a nuclear localization signal, which directed recombinant T7 RNAP to the P. pastoris nucleus. To promote translation of uncapped T7 RNAP derived transcripts, the internal ribosomal entry site from hepatitis C virus (HCV-IRES) was inserted directly upstream of the multiple cloning site of pEZT7. A P. pastoris autonomous replicating sequence (PARS1) was integrated into pEZT7 enabling propagation and recovery of plasmids from P. pastoris. Rapid amplification of 5' complementary DNA ends (5' RACE) experiments employing the test plasmid pEZT7-EGFP revealed that transcripts indeed initiated at pT7. HCV-IRES mediated translation of the latter mRNAs, however, was not observed. Surprisingly, HCV-IRES and the reverse complement of PARS1 (PARS1rc) were both found to display significant promoter activity as shown by 5' RACE.
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Affiliation(s)
- Birgit Hobl
- Institut für Technische Mikrobiologie, Hochschule Mannheim, 68163 Mannheim, Germany
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28
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Affiliation(s)
- C A Niño
- Institut Jacques Monod, Paris Diderot University , Sorbonne Paris Cité, CNRS UMR7592, Equipe labellisée Ligue contre le cancer, 15 rue Hélène Brion, 75205 Paris Cedex 13, France
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29
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Schor IE, Gómez Acuña LI, Kornblihtt AR. Coupling between transcription and alternative splicing. Cancer Treat Res 2013; 158:1-24. [PMID: 24222352 DOI: 10.1007/978-3-642-31659-3_1] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
The scenario of alternative splicing regulation is far more complex than the classical picture of a pre-mRNA being processed post-transcriptionally in more than one way. Introns are efficiently removed while transcripts are still being synthesized, supporting the idea of a co-transcriptional regulation of alternative splicing. Evidence of a functional coupling between splicing and transcription has recently emerged as it was observed that properties of one process may affect the outcome of the other. Co-transcriptionality is thought to improve splicing efficiency and kinetics by directing the nascent pre-mRNA into proper spliceosome assembly and favoring splicing factor recruitment. Two models have been proposed to explain the coupling of transcription and alternative splicing: in the recruitment model, promoters and pol II status affect the recruitment to the transcribing gene of splicing factors or bifunctional factors acting on both transcription and splicing; in the kinetic model, differences in the elongation rate of pol II would determine the timing in which splicing sites are presented, and thus the outcome of alternative splicing decisions. In the later model, chromatin structure has emerged as a key regulator. Although definitive evidence for transcriptionally coupled alternative splicing alterations in tumor development or cancer pathogenesis is still missing, many alternative splicing events altered in cancer might be subject to transcription-splicing coupling regulation.
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Affiliation(s)
- Ignacio E Schor
- Laboratorio de Fisiologia y Biologia Molecular, Departmento de Fisiologia, Biologia Molecular y Celular, IFIBYNE-CONICET, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, PAB. II, 20 Piso, Buenos Aires, 1428, Argentina
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Mischo HE, Proudfoot NJ. Disengaging polymerase: terminating RNA polymerase II transcription in budding yeast. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2012; 1829:174-85. [PMID: 23085255 PMCID: PMC3793857 DOI: 10.1016/j.bbagrm.2012.10.003] [Citation(s) in RCA: 106] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/02/2012] [Revised: 10/01/2012] [Accepted: 10/05/2012] [Indexed: 11/29/2022]
Abstract
Termination of transcription by RNA polymerase II requires two distinct processes: The formation of a defined 3′ end of the transcribed RNA, as well as the disengagement of RNA polymerase from its DNA template. Both processes are intimately connected and equally pivotal in the process of functional messenger RNA production. However, research in recent years has elaborated how both processes can additionally be employed to control gene expression in qualitative and quantitative ways. This review embraces these new findings and attempts to paint a broader picture of how this final step in the transcription cycle is of critical importance to many aspects of gene regulation. This article is part of a Special Issue entitled: RNA polymerase II Transcript Elongation.
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Affiliation(s)
- Hannah E Mischo
- Cancer Research UK London Research Institute, Blanche Lane South Mimms, Herts, UK.
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31
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Katahira J. mRNA export and the TREX complex. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2011; 1819:507-13. [PMID: 22178508 DOI: 10.1016/j.bbagrm.2011.12.001] [Citation(s) in RCA: 93] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2011] [Revised: 11/29/2011] [Accepted: 12/01/2011] [Indexed: 02/08/2023]
Abstract
Over the past few decades, we have learned that eukaryotes have evolved sophisticated means to coordinate the nuclear export of mRNAs with different steps of gene expression. This functional orchestration is important for the maintenance of the efficiency and fidelity of gene expression processes. The TREX (TRanscription-EXport) complex is an evolutionarily conserved multiprotein complex that plays a major role in the functional coupling of different steps during mRNA biogenesis, including mRNA transcription, processing, decay, and nuclear export. Furthermore, recent gene knockout studies in mice have revealed that the metazoan TREX complex is required for cell differentiation and development, likely because this complex regulates the expression of key genes. These newly identified roles for the TREX complex suggest the existence of a relationship between mRNA nuclear biogenesis and more complex cellular processes. This review describes the functional roles of the TREX complex in gene expression and the nuclear export of mRNAs. This article is part of a Special Issue entitled: Nuclear Transport and RNA Processing.
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Affiliation(s)
- Jun Katahira
- Biomolecular Networks Laboratories, Graduate School of Frontier Biosciences, Osaka University, Yamadaoka, Suita, Osaka, Japan.
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Luco RF, Allo M, Schor IE, Kornblihtt AR, Misteli T. Epigenetics in alternative pre-mRNA splicing. Cell 2011; 144:16-26. [PMID: 21215366 DOI: 10.1016/j.cell.2010.11.056] [Citation(s) in RCA: 593] [Impact Index Per Article: 45.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2010] [Revised: 09/07/2010] [Accepted: 11/13/2010] [Indexed: 12/11/2022]
Abstract
Alternative splicing plays critical roles in differentiation, development, and disease and is a major source for protein diversity in higher eukaryotes. Analysis of alternative splicing regulation has traditionally focused on RNA sequence elements and their associated splicing factors, but recent provocative studies point to a key function of chromatin structure and histone modifications in alternative splicing regulation. These insights suggest that epigenetic regulation determines not only what parts of the genome are expressed but also how they are spliced.
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Affiliation(s)
- Reini F Luco
- National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
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Suh MH, Meyer PA, Gu M, Ye P, Zhang M, Kaplan CD, Lima CD, Fu J. A dual interface determines the recognition of RNA polymerase II by RNA capping enzyme. J Biol Chem 2010; 285:34027-38. [PMID: 20720002 DOI: 10.1074/jbc.m110.145110] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
RNA capping enzyme (CE) is recruited specifically to RNA polymerase II (Pol II) transcription sites to facilitate cotranscriptional 5'-capping of pre-mRNA and other Pol II transcripts. The current model to explain this specific recruitment of CE to Pol II as opposed to Pol I and Pol III rests on the interaction between CE and the phosphorylated C-terminal domain (CTD) of Pol II largest subunit Rpb1 and more specifically between the CE nucleotidyltransferase domain and the phosphorylated CTD. Through biochemical and diffraction analyses, we demonstrate the existence of a distinctive stoichiometric complex between CE and the phosphorylated Pol II (Pol IIO). Analysis of the complex revealed an additional and unexpected polymerase-CE interface (PCI) located on the multihelical Foot domain of Rpb1. We name this interface PCI1 and the previously known nucleotidyltransferase/phosphorylated CTD interface PCI2. Although PCI1 and PCI2 individually contribute to only weak interactions with CE, a dramatically stabilized and stoichiometric complex is formed when PCI1 and PCI2 are combined in cis as they occur in an intact phosphorylated Pol II molecule. Disrupting either PCI1 or PCI2 by alanine substitution or deletion diminishes CE association with Pol II and causes severe growth defects in vivo. Evidence from manipulating PCI1 indicates that the Foot domain contributes to the specificity in CE interaction with Pol II as opposed to Pol I and Pol III. Our results indicate that the dual interface based on combining PCI1 and PCI2 is required for directing CE to Pol II elongation complexes.
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Affiliation(s)
- Man-Hee Suh
- Department of Biochemistry, Medical College of Wisconsin, Milwaukee, Wisconsin 53226, USA
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Zheng C, Fasken MB, Marshall NJ, Brockmann C, Rubinson ME, Wente SR, Corbett AH, Stewart M. Structural basis for the function of the Saccharomyces cerevisiae Gfd1 protein in mRNA nuclear export. J Biol Chem 2010; 285:20704-15. [PMID: 20463024 PMCID: PMC2898303 DOI: 10.1074/jbc.m110.107276] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2010] [Revised: 04/30/2010] [Indexed: 01/08/2023] Open
Abstract
Following transcription, mRNA is processed, packaged into messenger ribonucleoprotein (mRNP) particles, and transported through nuclear pores (NPCs) to the cytoplasm. At the NPC cytoplasmic face, Dbp5 mediates mRNP remodeling and mRNA export factor dissociation, releasing transcripts for translation. In Saccharomyces cerevisiae, the conserved poly(A) RNA-binding protein, Nab2, facilitates NPC targeting of transcripts and also modulates poly(A) tail length. Dbp5 removes Nab2 from mRNPs at the cytoplasmic face of the pore and, importantly, a Nab2 RNA-binding mutant suppresses the thermosensitive rat8-2 (dbp5) mutant. GFD1 is a multicopy suppressor of rat8-2 (dbp5), and Gfd1 interacts physically with both Dbp5 and the Nab2 N-terminal domain (Nab2-N). Here, we present a structural and functional analysis of the Gfd1/Nab2-N interaction. Crystallography, supported by solution NMR, shows that Gfd1 residues 126-150 form an alpha-helix when bound to Nab2-N. Engineered Nab2-N and Gfd1 mutants that inhibit this interaction in vitro were used to probe its function in vivo using the genetic interaction between GFD1 and NAB2. Although GFD1 is not essential for viability, its deletion severely impairs growth of rat8-2 (dbp5) cells. Moreover, although Gfd1 overexpression suppresses rat8-2 (dbp5), Gfd1 mutants that do not bind Nab2 only partially suppress rat8-2 (dbp5). Furthermore, rat8-2 (dbp5) cells that express nab2-Y34A, in which binding to Gfd1 is impaired, show a synthetic growth phenotype and nuclear accumulation of poly(A) RNA. These data support the importance of the Gfd1/Nab2 interaction for Dbp5 activity and provide further molecular details of the interactions that facilitate Dbp5-mediated mRNP remodeling in the terminal step of mRNA export.
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Affiliation(s)
- Chao Zheng
- From the MRC Laboratory of Molecular Biology, Hills Road, Cambridge CB2 0QH, United Kingdom
| | - Milo B. Fasken
- the Department of Biochemistry, Emory University School of Medicine, Atlanta, Georgia 30322, and
| | - Neil J. Marshall
- From the MRC Laboratory of Molecular Biology, Hills Road, Cambridge CB2 0QH, United Kingdom
| | - Christoph Brockmann
- From the MRC Laboratory of Molecular Biology, Hills Road, Cambridge CB2 0QH, United Kingdom
| | - Max E. Rubinson
- the Department of Biochemistry, Emory University School of Medicine, Atlanta, Georgia 30322, and
| | - Susan R. Wente
- the Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, Tennessee 37232
| | - Anita H. Corbett
- the Department of Biochemistry, Emory University School of Medicine, Atlanta, Georgia 30322, and
| | - Murray Stewart
- From the MRC Laboratory of Molecular Biology, Hills Road, Cambridge CB2 0QH, United Kingdom
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Wen J, Brogna S. Splicing-dependent NMD does not require the EJC in Schizosaccharomyces pombe. EMBO J 2010; 29:1537-51. [PMID: 20360683 PMCID: PMC2876954 DOI: 10.1038/emboj.2010.48] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2009] [Accepted: 03/04/2010] [Indexed: 12/04/2022] Open
Abstract
Nonsense-mediated mRNA decay (NMD) is a translation-linked process that destroys mRNAs with premature translation termination codons (PTCs). In mammalian cells, NMD is also linked to pre-mRNA splicing, usually PTCs trigger strong NMD only when positioned upstream of at least one intron. The exon junction complex (EJC) is believed to mediate the link between splicing and NMD in these systems. Here, we report that in Schizosaccharomyces pombe splicing also enhances NMD, but against the EJC model prediction, an intron stimulated NMD regardless of whether it is positioned upstream or downstream of the PTC and EJC components are not required. Still the effect of splicing seems to be direct-we have found that the important NMD determinant is the proximity of an intron to the PTC, not just the occurrence of splicing. On the basis of these results, we propose a new model to explain how splicing could affect NMD.
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Affiliation(s)
- Jikai Wen
- School of Biosciences, University of Birmingham, Edgbaston, Birmingham, UK
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Stewart M, Haile S, Jha BA, Cristodero M, Li CH, Clayton C. Processing of a phosphoglycerate kinase reporter mRNA in Trypanosoma brucei is not coupled to transcription by RNA polymerase II. Mol Biochem Parasitol 2010; 172:99-106. [PMID: 20363263 DOI: 10.1016/j.molbiopara.2010.03.016] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2009] [Revised: 03/08/2010] [Accepted: 03/27/2010] [Indexed: 11/30/2022]
Abstract
Capping of mRNAs is strictly coupled to RNA polymerase II transcription and there is evidence, mainly from metazoans, that other steps in pre-mRNA processing show a similar linkage. In trypanosomes, however, the mRNA cap is supplied by a trans spliced leader sequence. Thus pre-mRNAs transcribed by RNA Polymerase I are capped by trans splicing, and translation-competent transgenic mRNAs can be produced by RNA Polymerase I and T7 RNA polymerase so long as the primary transcript has a splice acceptor signal. We quantified the efficiency of processing of trypanosome pre-mRNAs produced from a plasmid integrated either at the tubulin locus, or in an rRNA spacer, and transcribed by RNA polymerase II, RNA polymerase I or T7 RNA polymerase. The processing efficiencies were similar for primary transcripts from the tubulin locus, produced by RNA polymerase II, and for RNA from an rRNA spacer, transcribed by RNA polymerase I. Primary transcripts produced by T7 RNA polymerase from the tubulin locus were processed almost as well. There was therefore no evidence for recruitment of the 3'-splicing apparatus by the RNA polymerase. Abundant transcripts transcribed from the rRNA locus by T7 RNA polymerase were somewhat less efficiently processed.
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Affiliation(s)
- Mhairi Stewart
- Zentrum für Molekularbiologie der Universität Heidelberg, ZMBH-DKFZ Alliance, Im Neuenheimer Feld 282, 69120 Heidelberg, Germany
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37
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Cotranslational assembly of the yeast SET1C histone methyltransferase complex. EMBO J 2009; 28:2959-70. [PMID: 19713935 DOI: 10.1038/emboj.2009.240] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2008] [Accepted: 07/28/2009] [Indexed: 01/21/2023] Open
Abstract
While probing the role of RNA for the function of SET1C/COMPASS histone methyltransferase, we identified SET1RC (SET1 mRNA-associated complex), a complex that contains SET1 mRNA and Set1, Swd1, Spp1 and Shg1, four of the eight polypeptides that constitute SET1C. Characterization of SET1RC showed that SET1 mRNA binding did not require associated Swd1, Spp1 and Shg1 proteins or RNA recognition motifs present in Set1. RNA binding was not observed when Set1 protein and SET1 mRNA were derived from independent genes or when SET1 transcripts were restricted to the nucleus. Importantly, the protein-RNA interaction was sensitive to EDTA, to the translation elongation inhibitor puromycin and to the inhibition of translation initiation in prt1-1 mutants. Taken together, our results support the idea that SET1 mRNA binding was dependent on translation and that SET1RC assembled on nascent Set1 in a cotranslational manner. Moreover, we show that cellular accumulation of Set1 is limited by the availability of certain SET1C components, such as Swd1 and Swd3, and suggest that cotranslational protein interactions may exert an effect in the protection of nascent Set1 from degradation.
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38
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Assembly of an export-competent mRNP is needed for efficient release of the 3'-end processing complex after polyadenylation. Mol Cell Biol 2009; 29:5327-38. [PMID: 19635808 DOI: 10.1128/mcb.00468-09] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Before polyadenylated mRNA is exported from the nucleus, the 3'-end processing complex is removed by a poorly described mechanism. In this study, we asked whether factors involved in mRNP maturation and export are also required for disassembly of the cleavage and polyadenylation complex. An RNA immunoprecipitation assay monitoring the amount of the cleavage factor (CF) IA component Rna15p associated with poly(A)(+) RNA reveals defective removal of Rna15p in mutants of the nuclear export receptor Mex67p as well as other factors important for assembly of an export-competent mRNP. In contrast, Rna15p is not retained in mutants of export factors that function primarily on the cytoplasmic side of the nuclear pore. Consistent with a functional interaction between Mex67p and the 3'-end processing complex, a mex67 mutant accumulates unprocessed SSA4 transcripts and exhibits a severe growth defect when this mutation is combined with mutation of Rna15p or another CF IA subunit, Rna14p. RNAs that become processed in a mex67 mutant have longer poly(A) tails both in vivo and in vitro. This influence of Mex67p on 3'-end processing is conserved, as depletion of its human homolog, TAP/NXF1, triggers mRNA hyperadenylation. Our results indicate a function for nuclear mRNP assembly factors in releasing the 3'-end processing complex once polyadenylation is complete.
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39
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Heat shock and ethanol stress provoke distinctly different responses in 3′-processing and nuclear export of HSP mRNA in Saccharomyces cerevisiae. Biochem J 2008; 414:111-9. [DOI: 10.1042/bj20071567] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Under conditions of heat shock at 42 °C, mRNAs of HSP (heat shock protein) genes are exported out of the nucleus, whereas bulk poly(A)+ (polyadenylated) mRNA shows a nuclear accumulation in Saccharomyces cerevisiae. Such a selective mRNA export seems an efficacious strategy of yeast cells to adapt rapidly to stress. Although ethanol stress (10%, v/v) as well as heat shock blocks the export of bulk poly(A)+ mRNA, the differences and/or similarity between heat shock and ethanol stress in the mechanisms of selective mRNA export still remain to be clarified. We found that ethanol stress induced transcriptional activation of a subset of yeast HSP genes; however, intriguingly, most such transcripts remained in the nucleus in a hyperadenylated state and, as a consequence, were not translated into HSPs. Elimination of ethanol resulted in a rapid shortening of the poly(A) tails of HSP mRNAs, loss of their nuclear retention, and the coincidental synthesis of the respective HSPs. Since HSP mRNAs are selectively exported from the nucleus in heat-shocked cells, yeast cells respond differently to ethanol stress and heat shock in the 3′-processing and transport of HSP mRNAs. Furthermore, these results also suggest that hyperadenylation and nuclear retention of mRNAs might be used as a means to control eukaryotic gene expression under stressed conditions.
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40
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Abstract
In eukaryotes, copying the genetic information from a DNA template into RNA is not sufficient itself to confer functional competence to the DNA-encoded message. mRNAs have to be processed by enzymes and packaged with proteins within nuclei to generate mRNP (messenger ribonucleoprotein) particles, before these can be exported to the cytoplasm. Processing and packaging factors are believed to interact with the nascent mRNA co-transcriptionally, which protects the highly reactive RNA molecule from a presumably aggressive nuclear environment while providing early commitment to its functional fate. In this review, we will describe the factors that are believed to provide the appropriate 'dress code' to the mRNA and the mechanisms underlying the proofreading events that guarantee its quality, focusing on yeast as a model system.
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41
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Cohen HR, Panning B. XIST RNA exhibits nuclear retention and exhibits reduced association with the export factor TAP/NXF1. Chromosoma 2007; 116:373-83. [PMID: 17333237 DOI: 10.1007/s00412-007-0100-1] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2006] [Revised: 12/18/2006] [Accepted: 01/18/2007] [Indexed: 10/23/2022]
Abstract
During splicing and polyadenylation, factors that stimulate export from the nucleus are recruited to nascent mRNAs. X-inactive specific transcript (XIST) RNA is unusual among capped, spliced, polyadenylated transcripts in that it accumulates exclusively in the nucleus. It is well established that, at steady state levels, XIST RNA is primarily nuclear. However, it was unknown whether XIST RNA spends its entire lifetime in the nucleus (nuclear retention) or passes briefly through the cytoplasm during maturation, like many other functional RNAs. In this study, we present the first evidence that XIST RNA exhibits nuclear retention. We report that a green fluorescent protein (GFP)-XIST fusion RNA is detected in the nucleus and not the cytoplasm, and GFP is not translated. XIST RNA does not shuttle in a heterokaryon assay or move between chromosomes in the same nucleus when expressed at wild-type levels. These results indicate that XIST RNA's nuclear localization is mediated by nuclear retention rather than export followed by import. We present evidence that the export factor TAP/NXF1 binds poorly to XIST RNA in comparison to exported mRNAs, suggesting that reduced TAP/NFX1 binding may contribute to nuclear retention of XIST RNA.
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Affiliation(s)
- Hannah R Cohen
- Department of Biochemistry and Biophysics, University of California San Francisco, Genentech Hall, Room S372B, 600 16th Street, San Francisco, CA 94143-2200, USA
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42
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Kornblihtt AR. Coupling Transcription and Alternative Splicing. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2007; 623:175-89. [DOI: 10.1007/978-0-387-77374-2_11] [Citation(s) in RCA: 135] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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43
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Zhelkovsky A, Tacahashi Y, Nasser T, He X, Sterzer U, Jensen TH, Domdey H, Moore C. The role of the Brr5/Ysh1 C-terminal domain and its homolog Syc1 in mRNA 3'-end processing in Saccharomyces cerevisiae. RNA (NEW YORK, N.Y.) 2006; 12:435-45. [PMID: 16431986 PMCID: PMC1383582 DOI: 10.1261/rna.2267606] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
The cleavage/polyadenylation factor (CPF) of Saccharomyces cerevisiae is thought to provide the catalytic activities of the mRNA 3'-end processing machinery, which include endonucleolytic cleavage at the poly(A) site, followed by synthesis of an adenosine polymer onto the new 3'-end by the CPF subunit Pap1. Because of similarity to other nucleases in the metallo-beta-lactamase family, the Brr5/Ysh1 subunit has been proposed to be the endonuclease. The C-terminal domain of Brr5 lies outside of beta-lactamase homology, and its function has not been elucidated. We show here that this region of Brr5 is necessary for cell viability and mRNA 3'-end processing. It is highly homologous to another CPF subunit, Syc1. Syc1 is not essential, but its removal improves the growth of other processing mutants at restrictive temperatures and restores in vitro processing activity to cleavage/ polyadenylation-defective brr5-1 extract. Our findings suggest that Syc1, by mimicking the essential Brr5 C-terminus, serves as a negative regulator of mRNA 3'-end formation.
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Affiliation(s)
- Alexander Zhelkovsky
- Department of Molecular Microbiology, Tufts University School of Medicine, Boston, MA 02111, USA
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44
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Bird G, Fong N, Gatlin JC, Farabaugh S, Bentley DL. Ribozyme cleavage reveals connections between mRNA release from the site of transcription and pre-mRNA processing. Mol Cell 2006; 20:747-58. [PMID: 16337598 DOI: 10.1016/j.molcel.2005.11.009] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2005] [Revised: 10/21/2005] [Accepted: 11/09/2005] [Indexed: 11/23/2022]
Abstract
We report a functional connection between splicing and transcript release from the DNA. A Pol II CTD mutant inhibited not only splicing but also RNA release from the site of transcription. A ribozyme situated downstream of the gene restored accurate splicing inhibited by the CTD mutant or a mutant poly(A) site, suggesting that cleavage liberates RNA from a niche that is inaccessible to splicing factors. Although ribozyme cleavage enhanced splicing, 3' end processing was impaired, indicating that an intact RNA chain linking the poly(A) site to Pol II is required for optimal processing. Surprisingly, poly(A)(-) beta-globin mRNA with a ribozyme-generated 3' end was exported to the cytoplasm. Ribozyme cleavage can therefore substitute for normal 3' end processing in stimulating splicing and mRNA export. We propose that mRNA biogenesis is coordinated by preventing splicing near the 3' end until the transcript is released by poly(A) site cleavage.
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Affiliation(s)
- Gregory Bird
- Department of Biochemistry and Molecular Genetics, University of Colorado School of Medicine, UCHSC at Fitzsimons, Aurora, 80045, USA
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45
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Abstract
mRNAs are transported from the nucleus to the cytoplasm by a machinery conserved from yeast to humans. Previous studies showed that mRNA export factors are loaded on nascent mRNAs during elongation, coupling transcription to export. More recently identified mRNA export factors connect transcription initiation to the export machinery associated with nuclear pores, and potentially tether active genes to the nuclear periphery. Furthermore, a newly identified link between the nuclear exosome and the transcription, 3'-end formation and export machineries suggests that early messenger ribonucleoprotein complex (mRNP) assembly is co-transcriptionally monitored. Moreover, inefficient mRNP assembly impairs transcription elongation, indicating tight interdependence of these processes. Finally, nuclear retention of unspliced mRNAs by the perinuclear Mlp proteins reveals a novel mechanism of mRNP surveillance prior to export.
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Affiliation(s)
- Patrizia Vinciguerra
- Department of Cell Biology, University of Geneva, Sciences III, 30 Quai E. Ansermet, 1211 Geneva 4, Switzerland
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46
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Saguez C, Olesen JR, Jensen TH. Formation of export-competent mRNP: escaping nuclear destruction. Curr Opin Cell Biol 2005; 17:287-93. [PMID: 15901499 DOI: 10.1016/j.ceb.2005.04.009] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
In eukaryotic cells, primary transcripts are processed and bound by proteins before export to the cytoplasm. Nuclear production of export-competent messenger ribonucleoprotein particles (mRNPs) is a complicated process, and mRNP biogenic events that function sub-optimally are rapidly attacked by surveillance leading to degradation of the mRNA. Export of nuclear mRNAs is therefore constantly challenged by the opposing force of mRNA retention and decay. This balance ensures that only 'perfect' transcripts persist, and that non-functional and potentially deleterious transcripts are removed early in their biogenesis. Thus, eukaryotic systems of mRNP quality control can be viewed as simple Darwinian principles operating at the molecular level.
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Affiliation(s)
- Cyril Saguez
- Department of Molecular Biology, Arhus University, CF Møllers Alle, bldg. 130, 8000 Arhus C, Denmark
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47
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Abstract
Recent findings justify a renewed interest in alternative splicing (AS): the process is more a rule than an exception as it affects the expression of 60% of human genes; it explains how a vast mammalian proteomic complexity is achieved with a limited number of genes; and mutations in AS regulatory sequences are a widespread source of human disease. AS regulation not only depends on the interaction of splicing factors with their target sequences in the pre-mRNA but is coupled to transcription. A clearer picture is emerging of the mechanisms by which transcription affects AS through promoter identity and occupation. These mechanisms involve the recruitment of factors with dual functions in transcription and splicing (i.e. that contain both functional domains and hence link the two processes) and the control of RNA polymerase II elongation.
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Affiliation(s)
- Alberto R Kornblihtt
- Laboratorio de Fisiologia y Biologia Molecular, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Pabellon 2, 2 piso, C1428EHA Buenos Aires, Argentina.
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48
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Görnemann J, Kotovic KM, Hujer K, Neugebauer KM. Cotranscriptional spliceosome assembly occurs in a stepwise fashion and requires the cap binding complex. Mol Cell 2005; 19:53-63. [PMID: 15989964 DOI: 10.1016/j.molcel.2005.05.007] [Citation(s) in RCA: 213] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2005] [Revised: 04/05/2005] [Accepted: 05/09/2005] [Indexed: 10/25/2022]
Abstract
Coupling between transcription and pre-mRNA splicing is a key regulatory mechanism in gene expression. Here, we investigate cotranscriptional spliceosome assembly in yeast, using in vivo crosslinking to determine the distribution of spliceosome components along intron-containing genes. Accumulation of the U1, U2, and U5 small nuclear ribonucleoprotein particles (snRNPs) and the 3' splice site binding factors Mud2p and BBP was detected in patterns indicative of progressive and complete spliceosome assembly; recruitment of the nineteen complex (NTC) component Prp19p suggests that splicing catalysis is also cotranscriptional. The separate dynamics of the U1, U2, and U5 snRNPs are consistent with stepwise recruitment of individual snRNPs rather than a preformed "penta-snRNP", as recently proposed. Finally, we show that the cap binding complex (CBC) is necessary, but not sufficient, for cotranscriptional spliceosome assembly. Thus, the demonstration of an essential link between CBC and spliceosome assembly in vivo indicates that 5' end capping couples pre-mRNA splicing to transcription.
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Affiliation(s)
- Janina Görnemann
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstrasse 108, 01307 Dresden, Germany
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49
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Kushnir S, Gase K, Breitling R, Alexandrov K. Development of an inducible protein expression system based on the protozoan host Leishmania tarentolae. Protein Expr Purif 2005; 42:37-46. [PMID: 15939291 DOI: 10.1016/j.pep.2005.03.004] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2004] [Revised: 02/27/2005] [Accepted: 03/02/2005] [Indexed: 11/23/2022]
Abstract
Production of functional eukaryotic proteins in recombinant form is a bottle-neck in various post-genomic applications and in life science in general. At least partially this is due to the problems associated with the use of endogenous RNA polymerase II for high-level transcription of heterologous genes in eukaryotic expression systems. To circumvent these problems we developed a new inducible protein expression system based on the protozoan host Leishmania tarentolae (Trypanosomatidae). We have created a strain of L. tarentolae constitutively co-expressing T7 RNA polymerase and tetracycline repressor. This strain could be stably transformed with the heterologous target gene under control of the T7 promoter/TET operator assembly, which can initiate transcription upon addition of tetracycline to the culture medium. Using this system, we demonstrated that enhanced green fluorescent protein (EGFP) could be overexpressed to a level of ca. 1% of total cellular protein. The developed system was tested for its ability to inducibly co-express multiple genes. Using two copies of the egfp gene integrated at two different genomic sites, we could obtain expression levels reaching 4% of total cellular protein. Further possible improvements and applications of the developed system are discussed.
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Affiliation(s)
- Susanna Kushnir
- Department of Physical Biochemistry, Max-Planck-Institute for Molecular Physiology, Dortmund, Germany
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50
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Conrad NK, Steitz JA. A Kaposi's sarcoma virus RNA element that increases the nuclear abundance of intronless transcripts. EMBO J 2005; 24:1831-41. [PMID: 15861127 PMCID: PMC1142595 DOI: 10.1038/sj.emboj.7600662] [Citation(s) in RCA: 89] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2005] [Accepted: 04/06/2005] [Indexed: 11/09/2022] Open
Abstract
The Kaposi's sarcoma-associated herpesvirus produces a 1077 nucleotide noncoding, polyadenylated, exclusively nuclear RNA called PAN that is highly expressed in lytically infected cells. We report that PAN contains a novel post-transcriptional element essential for its abundant accumulation. The element, PAN-ENE (PAN RNA expression and nuclear retention element), increases the efficiency of 3'-end formation in vivo and is sufficient to enhance RNA abundance from an otherwise inefficiently expressed intronless beta-globin construct. The PAN-ENE does not concomitantly increase the production of encoded protein. Rather, it retains the unspliced beta-globin mRNA in the nucleus. Tethering of export factors can override the nuclear retention of the PAN-ENE, supporting a mechanism whereby the PAN-ENE blocks assembly of an export-competent mRNP. The activities of the PAN-ENE are specific to intronless constructs, since inserting the PAN-ENE into a spliced beta-globin construct has no effect on mRNA abundance and does not affect localization. This is the first characterization of a cis-acting element that increases RNA abundance of intronless transcripts but inhibits assembly of an export-competent mRNP.
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Affiliation(s)
- Nicholas K Conrad
- Department of Molecular Biophysics and Biochemistry, Howard Hughes Medical Institute, Yale University, New Haven, CT, USA
| | - Joan A Steitz
- Department of Molecular Biophysics and Biochemistry, Howard Hughes Medical Institute, Yale University, New Haven, CT, USA
- Department of Molecular Biophysics and Biochemistry, Howard Hughes Medical Institute, Yale University, New Haven, CT 06536, USA. Tel.: +1 203 737 4418; Fax: +1 203 624 8213; E-mail:
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