1
|
Clark L, Voigt CA, Jewett MC. Establishing a High-Yield Chloroplast Cell-Free System for Prototyping Genetic Parts. ACS Synth Biol 2024. [PMID: 39023433 DOI: 10.1021/acssynbio.4c00111] [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: 07/20/2024]
Abstract
Plastid engineering offers the potential to carry multigene traits in plants; however, it requires reliable genetic parts to balance expression. The difficulty of chloroplast transformation and slow plant growth makes it challenging to build plants just to characterize genetic parts. To address these limitations, we developed a high-yield cell-free system from Nicotiana tabacum chloroplast extracts for prototyping genetic parts. Our cell-free system uses combined transcription and translation driven by T7 RNA polymerase and works with plasmid or linear template DNA. To develop our system, we optimized lysis, extract preparation procedures (e.g., runoff reaction, centrifugation, and dialysis), and the physiochemical reaction conditions. Our cell-free system can synthesize 34 ± 1 μg/mL luciferase in batch reactions and 60 ± 4 μg/mL in semicontinuous reactions. We apply our batch reaction system to test a library of 103 ribosome binding site (RBS) variants and rank them based on cell-free gene expression. We observe a 1300-fold dynamic range of luciferase expression when normalized by maximum mRNA expression, as assessed by the malachite green aptamer. We also find that the observed normalized gene expression in chloroplast extracts and the predictions made by the RBS Calculator are correlated. We anticipate that chloroplast cell-free systems will increase the speed and reliability of building genetic systems in plant chloroplasts for diverse applications.
Collapse
Affiliation(s)
- Lauren Clark
- Department of Chemical and Biological Engineering, Northwestern University, Evanston, Illinois 60208, United States
- Chemistry of Life Processes Institute, Evanston, Illinois 60208, United States
- Center for Synthetic Biology, Northwestern University, Evanston, Illinois 60208, United States
| | - Christopher A Voigt
- Synthetic Biology Center, Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States
| | - Michael C Jewett
- Department of Chemical and Biological Engineering, Northwestern University, Evanston, Illinois 60208, United States
- Chemistry of Life Processes Institute, Evanston, Illinois 60208, United States
- Center for Synthetic Biology, Northwestern University, Evanston, Illinois 60208, United States
- Robert H. Lurie Comprehensive Cancer Center, Chicago, Illinois 60611, United States
- Simpson Querrey Institute, Northwestern University, Chicago, Illinois 60611, United States
- Department of Bioengineering, Stanford University, Stanford, California 94305, United States
| |
Collapse
|
2
|
Murthy D, Attri KS, Shukla SK, Thakur R, Chaika NV, He C, Wang D, Jha K, Dasgupta A, King RJ, Mulder SE, Souchek J, Gebregiworgis T, Rai V, Patel R, Hu T, Rana S, Kollala SS, Pacheco C, Grandgenett PM, Yu F, Kumar V, Lazenby AJ, Black AR, Ulhannan S, Jain A, Edil BH, Klinkebiel DL, Powers R, Natarajan A, Hollingsworth MA, Mehla K, Ly Q, Chaudhary S, Hwang RF, Wellen KE, Singh PK. Cancer-associated fibroblast-derived acetate promotes pancreatic cancer development by altering polyamine metabolism via the ACSS2-SP1-SAT1 axis. Nat Cell Biol 2024; 26:613-627. [PMID: 38429478 PMCID: PMC11021164 DOI: 10.1038/s41556-024-01372-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2020] [Accepted: 02/02/2024] [Indexed: 03/03/2024]
Abstract
The ability of tumour cells to thrive in harsh microenvironments depends on the utilization of nutrients available in the milieu. Here we show that pancreatic cancer-associated fibroblasts (CAFs) regulate tumour cell metabolism through the secretion of acetate, which can be blocked by silencing ATP citrate lyase (ACLY) in CAFs. We further show that acetyl-CoA synthetase short-chain family member 2 (ACSS2) channels the exogenous acetate to regulate the dynamic cancer epigenome and transcriptome, thereby facilitating cancer cell survival in an acidic microenvironment. Comparative H3K27ac ChIP-seq and RNA-seq analyses revealed alterations in polyamine homeostasis through regulation of SAT1 gene expression and enrichment of the SP1-responsive signature. We identified acetate/ACSS2-mediated acetylation of SP1 at the lysine 19 residue that increased SP1 protein stability and transcriptional activity. Genetic or pharmacologic inhibition of the ACSS2-SP1-SAT1 axis diminished the tumour burden in mouse models. These results reveal that the metabolic flexibility imparted by the stroma-derived acetate enabled cancer cell survival under acidosis via the ACSS2-SP1-SAT1 axis.
Collapse
Affiliation(s)
- Divya Murthy
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE, USA
| | - Kuldeep S Attri
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE, USA
| | - Surendra K Shukla
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE, USA
- Department of Oncology Science, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Ravi Thakur
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE, USA
- Department of Oncology Science, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Nina V Chaika
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE, USA
| | - Chunbo He
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE, USA
| | - Dezhen Wang
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE, USA
| | - Kanupriya Jha
- Department of Biotechnology, School of Engineering and Applied Sciences, Bennett University, Greater Noida, Uttar Pradesh, India
| | - Aneesha Dasgupta
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE, USA
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE, USA
| | - Ryan J King
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE, USA
| | - Scott E Mulder
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE, USA
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE, USA
| | - Joshua Souchek
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE, USA
| | - Teklab Gebregiworgis
- Department of Chemistry, University of Nebraska-Lincoln, Lincoln, NE, USA
- Department of Biochemistry, Schulich School of Medicine & Dentistry, University of Western Ontario, London, Ontario, Canada
| | - Vikant Rai
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE, USA
| | - Rohit Patel
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE, USA
| | - Tuo Hu
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE, USA
| | - Sandeep Rana
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE, USA
| | - Sai Sundeep Kollala
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE, USA
| | - Camila Pacheco
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE, USA
| | - Paul M Grandgenett
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE, USA
| | - Fang Yu
- Department of Biostatistics, University of Nebraska Medical Center, Omaha, NE, USA
| | - Vikas Kumar
- Department of Cell Biology, Genetics and Anatomy, University of Nebraska Medical Center, Omaha, NE, USA
| | - Audrey J Lazenby
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, NE, USA
| | - Adrian R Black
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE, USA
| | - Susanna Ulhannan
- Department of Internal Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Ajay Jain
- Department of Surgery, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Barish H Edil
- Department of Surgery, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - David L Klinkebiel
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE, USA
| | - Robert Powers
- Department of Chemistry, University of Nebraska-Lincoln, Lincoln, NE, USA
- Nebraska Center for Integrated Biomolecular Communication, University of Nebraska-Lincoln, Lincoln, NE, USA
| | - Amarnath Natarajan
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE, USA
| | - Michael A Hollingsworth
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE, USA
| | - Kamiya Mehla
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE, USA
- Department of Oncology Science, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Quan Ly
- Department of Surgical Oncology, University of Nebraska Medical Center, Omaha, NE, USA
| | - Sarika Chaudhary
- Department of Biotechnology, School of Engineering and Applied Sciences, Bennett University, Greater Noida, Uttar Pradesh, India
| | - Rosa F Hwang
- Department of Surgical Oncology, Division of Surgery, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Kathryn E Wellen
- Department of Cancer Biology, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| | - Pankaj K Singh
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE, USA.
- Department of Oncology Science, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA.
- OU Health Stephenson Cancer Center, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA.
| |
Collapse
|
3
|
Pitolli M, Cela M, Paulus C, Rudinger-Thirion J, Frugier M. RNA aptamers developed against tRip: A preliminary approach targeting tRNA entry in Plasmodium. Biochimie 2024; 217:106-115. [PMID: 37414209 DOI: 10.1016/j.biochi.2023.06.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Revised: 05/26/2023] [Accepted: 06/24/2023] [Indexed: 07/08/2023]
Abstract
Malaria is caused by Plasmodium parasites that multiply inside host cells and can be lethal when P. falciparum is involved. We identified tRip as a membrane protein that facilitates the import of exogenous transfer RNA (tRNA) into the parasite. tRip encompasses a tRNA binding domain exposed on the parasite surface. We used the SELEX approach to isolate high-affinity and specific tRip-binding RNA motifs from a library of random 25 nucleotide-long sequences. In five rounds of combined negative and positive selections, an enriched pool of aptamers was obtained; sequencing revealed that they were all different in their primary sequence; only by comparing their structure predictions did most of the selected aptamers reveal a conserved 5-nucleotide motif sequence. We showed that the integral motif is essential for tRip-binding while the rest of the molecule can be significantly reduced or mutated as long as the motif is presented in a single-stranded region. Such RNA aptamers bind in place of the original tRNA substrate and act as an efficient competitor, suggesting that they can block tRip function and slow parasite development.
Collapse
Affiliation(s)
- Martina Pitolli
- Université de Strasbourg, CNRS, Architecture et Réactivité de l'ARN, UPR 9002, F-67084, Strasbourg, France
| | - Marta Cela
- Université de Strasbourg, CNRS, Architecture et Réactivité de l'ARN, UPR 9002, F-67084, Strasbourg, France
| | - Caroline Paulus
- Université de Strasbourg, CNRS, Architecture et Réactivité de l'ARN, UPR 9002, F-67084, Strasbourg, France
| | - Joëlle Rudinger-Thirion
- Université de Strasbourg, CNRS, Architecture et Réactivité de l'ARN, UPR 9002, F-67084, Strasbourg, France
| | - Magali Frugier
- Université de Strasbourg, CNRS, Architecture et Réactivité de l'ARN, UPR 9002, F-67084, Strasbourg, France.
| |
Collapse
|
4
|
Rojas-Luna L, Posadas-Modragón A, Avila-Trejo AM, Alcántara-Farfán V, Rodríguez-Páez LI, Santiago-Cruz JA, Pastor-Alonso MO, Aguilar-Faisal JL. Inhibition of chikungunya virus replication by N-ω-Chloroacetyl-L-Ornithine in C6/36, Vero cells and human fibroblast BJ. Antivir Ther 2023; 28:13596535231155263. [PMID: 36724136 DOI: 10.1177/13596535231155263] [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: 02/02/2023]
Abstract
BACKGROUND Polyamines are involved in several cellular processes and inhibiting their synthesis affects chikungunya virus (CHIKV) replication and translation, and, therefore, reduces the quantity of infectious viral particles produced. In this study, we evaluated the inhibition of CHIKV replication by N-ω-chloroacetyl-L-ornithine (NCAO), a competitive inhibitor of ornithine decarboxylase, an enzyme which is key in the biosynthesis of polyamines (PAs). METHODS The cytotoxicity of NCAO was evaluated by MTT in cell culture. The inhibitory effect of CHIKV replication by NCAO was evaluated in Vero and C6/36 cells. The intracellular polyamines were quantified by HPLC in CHIKV-infected cells. We evaluated the yield of CHIKV in titres via the addition of PAs in Vero, C6/36 cells and human fibroblast BJ treated with NCAO. RESULTS We found that NCAO inhibits the replication of CHIKV in Vero and C6/36 cells in a dose-dependent manner, causing a decrease in the PFU/mL of at least 4 logarithms (p < 0.01) in both cell lines. Viral yields were restored by the addition of exogenous polyamines, mainly putrescine. The HPLC analyses showed that NCAO decreases the content of intracellular PAs, even though it is predominantly spermidines and spermines which are present in infected cells. Inhibition of CHIKV replication was observed in human fibroblast BJ treated with 100 μM NCAO 24 h before and 48 h after the infection at a MOI 1. CONCLUSIONS NCAO inhibits CHIKV replication by depleting the intracellular polyamines in Vero, C6/36 cells and human fibroblast BJ, suggesting that this compound is a possible antiviral agent for CHIKV.
Collapse
Affiliation(s)
- Lucero Rojas-Luna
- Laboratorio de Medicina de Conservación, Sección de Estudios de Posgrado e Investigación, Escuela Superior de Medicina, 27740Instituto Politécnico Nacional, Mexico City, Mexico
| | - Araceli Posadas-Modragón
- Laboratorio de Medicina de Conservación, Sección de Estudios de Posgrado e Investigación, Escuela Superior de Medicina, 27740Instituto Politécnico Nacional, Mexico City, Mexico
| | - Amanda M Avila-Trejo
- Laboratorio de Medicina de Conservación, Sección de Estudios de Posgrado e Investigación, Escuela Superior de Medicina, 27740Instituto Politécnico Nacional, Mexico City, Mexico.,Laboratorio de Bioquímica Farmacológica, 61735Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Mexico City, Mexico
| | - Verónica Alcántara-Farfán
- Laboratorio de Bioquímica Farmacológica, 61735Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Mexico City, Mexico
| | - Lorena I Rodríguez-Páez
- Laboratorio de Bioquímica Farmacológica, 61735Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Mexico City, Mexico
| | - José Angel Santiago-Cruz
- Laboratorio de Medicina de Conservación, Sección de Estudios de Posgrado e Investigación, Escuela Superior de Medicina, 27740Instituto Politécnico Nacional, Mexico City, Mexico
| | - Marvin O Pastor-Alonso
- Laboratorio de Medicina de Conservación, Sección de Estudios de Posgrado e Investigación, Escuela Superior de Medicina, 27740Instituto Politécnico Nacional, Mexico City, Mexico
| | - J Leopoldo Aguilar-Faisal
- Laboratorio de Medicina de Conservación, Sección de Estudios de Posgrado e Investigación, Escuela Superior de Medicina, 27740Instituto Politécnico Nacional, Mexico City, Mexico
| |
Collapse
|
5
|
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.
Collapse
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
| |
Collapse
|
6
|
Cruz-Pulido YE, Mounce BC. Good cop, bad cop: Polyamines play both sides in host immunity and viral replication. Semin Cell Dev Biol 2023; 146:70-79. [PMID: 36604249 PMCID: PMC10101871 DOI: 10.1016/j.semcdb.2022.12.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Revised: 12/12/2022] [Accepted: 12/13/2022] [Indexed: 01/05/2023]
Abstract
Viruses rely on host cells for energy and synthesis machinery required for genome replication and particle assembly. Due to the dependence of viruses on host cells, viruses have evolved multiple mechanisms by which they can induce metabolic changes in the host cell to suit their specific requirements. The host immune response also involves metabolic changes to be able to react to viral insult. Polyamines are small ubiquitously expressed polycations, and their metabolism is critical for viral replication and an adequate host immune response. This is due to the variety of functions that polyamines have, ranging from condensing DNA to enhancing the translation of polyproline-containing proteins through the hypusination of eIF5A. Here, we review the diverse mechanisms by which viruses exploit polyamines, as well as the mechanisms by which immune cells utilize polyamines for their functions. Furthermore, we highlight potential avenues for further study of the host-virus interface.
Collapse
Affiliation(s)
- Yazmin E Cruz-Pulido
- Department of Microbiology and Immunology, Loyola University Chicago Stritch School of Medicine, Maywood, IL, USA
| | - Bryan C Mounce
- Department of Microbiology and Immunology, Loyola University Chicago Stritch School of Medicine, Maywood, IL, USA; Infectious Disease and Immunology Research Institute, Loyola University Chicago Stritch School of Medicine, Maywood, IL, USA.
| |
Collapse
|
7
|
Rosa SS, Nunes D, Antunes L, Prazeres DMF, Marques MPC, Azevedo AM. Maximizing mRNA vaccine production with bayesian optimization. Biotechnol Bioeng 2022; 119:3127-3139. [PMID: 36017534 PMCID: PMC9539360 DOI: 10.1002/bit.28216] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2022] [Revised: 08/18/2022] [Accepted: 08/21/2022] [Indexed: 11/29/2022]
Abstract
Messenger RNA (mRNA) vaccines are a new alternative to conventional vaccines with a prominent role in infectious disease control. These vaccines are produced in in vitro transcription (IVT) reactions, catalyzed by RNA polymerase in cascade reactions. To ensure an efficient and cost‐effective manufacturing process, essential for a large‐scale production and effective vaccine supply chain, the IVT reaction needs to be optimized. IVT is a complex reaction that contains a large number of variables that can affect its outcome. Traditional optimization methods rely on classic Design of Experiments methods, which are time‐consuming and can present human bias or based on simplified assumptions. In this contribution, we propose the use of Machine Learning approaches to perform a data‐driven optimization of an mRNA IVT reaction. A Bayesian optimization method and model interpretability techniques were used to automate experiment design, providing a feedback loop. IVT reaction conditions were found under 60 optimization runs that produced 12 g · L−1 in solely 2 h. The results obtained outperform published industry standards and data reported in literature in terms of both achievable reaction yield and reduction of production time. Furthermore, this shows the potential of Bayesian optimization as a cost‐effective optimization tool within (bio)chemical applications.
Collapse
Affiliation(s)
- Sara Sousa Rosa
- Department of Bioengineering, iBB-Institute for Bioengineering and Biosciences, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001, Lisboa, Portugal.,Associate Laboratory i4HB-Institute for Health and Bioeconomy, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001, Lisboa, Portugal
| | - Davide Nunes
- LASIGE, Faculdade de Ciências da Universidade de Lisboa, Campo Grande, 1749 - 016, Lisboa, Portugal
| | - Luis Antunes
- LASIGE, Faculdade de Ciências da Universidade de Lisboa, Campo Grande, 1749 - 016, Lisboa, Portugal
| | - Duarte M F Prazeres
- Department of Bioengineering, iBB-Institute for Bioengineering and Biosciences, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001, Lisboa, Portugal.,Associate Laboratory i4HB-Institute for Health and Bioeconomy, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001, Lisboa, Portugal
| | - Marco P C Marques
- Department of Biochemical Engineering, University College London, Bernard Katz Building, Gordon Street, London, WC1H 0AH, United Kingdom
| | - Ana M Azevedo
- Department of Bioengineering, iBB-Institute for Bioengineering and Biosciences, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001, Lisboa, Portugal.,Associate Laboratory i4HB-Institute for Health and Bioeconomy, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001, Lisboa, Portugal
| |
Collapse
|
8
|
Fiches GN, Wu Z, Zhou D, Biswas A, Li TW, Kong W, Jean M, Santoso NG, Zhu J. Polyamine biosynthesis and eIF5A hypusination are modulated by the DNA tumor virus KSHV and promote KSHV viral infection. PLoS Pathog 2022; 18:e1010503. [PMID: 35486659 PMCID: PMC9094511 DOI: 10.1371/journal.ppat.1010503] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Revised: 05/11/2022] [Accepted: 04/05/2022] [Indexed: 12/12/2022] Open
Abstract
Polyamines are critical metabolites involved in various cellular processes and often dysregulated in cancers. Kaposi’s sarcoma-associated Herpesvirus (KSHV), a defined human oncogenic virus, leads to profound alterations of host metabolic landscape to favor development of KSHV-associated malignancies. In our studies, we identified that polyamine biosynthesis and eIF5A hypusination are dynamically regulated by KSHV infection through modulation of key enzymes (ODC1 and DHPS) of these pathways. During KSHV latency, ODC1 and DHPS are upregulated along with increase of hypusinated eIF5A (hyp-eIF5A), while hyp-eIF5A is further induced along with reduction of ODC1 and intracellular polyamines during KSHV lytic reactivation. In return these metabolic pathways are required for both KSHV lytic reactivation and de novo infection. Further analysis unraveled that synthesis of critical KSHV latent and lytic proteins (LANA, RTA) depends on hypusinated-eIF5A. We also demonstrated that KSHV infection can be efficiently and specifically suppressed by inhibitors targeting these pathways. Collectively, our results illustrated that the dynamic and profound interaction of a DNA tumor virus (KSHV) with host polyamine biosynthesis and eIF5A hypusination pathways promote viral propagation, thus defining new therapeutic targets to treat KSHV-associated malignancies. Understanding virus-host interactions is crucial to develop and improve therapies. Kaposi’s sarcoma associated Herpesvirus (KSHV) is a human gamma-herpesvirus which deeply modulates the host metabolism and is associated with various cancers of endothelial and lymphoid origin. Polyamines are critical metabolites often dysregulated in cancers. In this study we demonstrated KSHV dynamically modulates polyamine metabolism to favor eIF5A hypusination and translation of critical KSHV latent and lytic proteins (LANA, RTA). Consequently, we found KSHV lytic switch from latency and de novo infection were dependent on polyamines and hypusination and pharmacological inhibition efficiently and specifically restricted KSHV infection. Our study provides new insights into KSHV alteration of the host metabolism and describe new therapeutic targets to treat KSHV-associated malignancies.
Collapse
Affiliation(s)
- Guillaume N. Fiches
- Department of Pathology, Ohio State University College of Medicine, Columbus, Ohio, United States of America
| | - Zhenyu Wu
- Department of Pathology, Ohio State University College of Medicine, Columbus, Ohio, United States of America
| | - Dawei Zhou
- Department of Pathology, Ohio State University College of Medicine, Columbus, Ohio, United States of America
| | - Ayan Biswas
- Department of Genetics, School of Medicine, University of Alabama at Birmingham, Birmingham, Alabama, United States of America
| | - Tai-Wei Li
- Department of Pathology, Ohio State University College of Medicine, Columbus, Ohio, United States of America
| | - Weili Kong
- Gladstone Institute of Virology and Immunology, University of California, San Francisco, California, United States of America
| | - Maxime Jean
- Department of Neurology, University of Rochester Medical center, Rochester, New York, United States of America
| | - Netty G. Santoso
- Department of Pathology, Ohio State University College of Medicine, Columbus, Ohio, United States of America
| | - Jian Zhu
- Department of Pathology, Ohio State University College of Medicine, Columbus, Ohio, United States of America
- * E-mail:
| |
Collapse
|
9
|
Firpo MR, Mastrodomenico V, Hawkins GM, Prot M, Levillayer L, Gallagher T, Simon-Loriere E, Mounce BC. Targeting Polyamines Inhibits Coronavirus Infection by Reducing Cellular Attachment and Entry. ACS Infect Dis 2021; 7:1423-1432. [PMID: 32966040 PMCID: PMC7539557 DOI: 10.1021/acsinfecdis.0c00491] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Indexed: 12/25/2022]
Abstract
Coronaviruses first garnered widespread attention in 2002 when the severe acute respiratory syndrome coronavirus (SARS-CoV) emerged from bats in China and rapidly spread in human populations. Since then, Middle East respiratory syndrome coronavirus (MERS-CoV) emerged and still actively infects humans. The recent SARS-CoV-2 outbreak and the resulting disease (coronavirus disease 2019, COVID19) have rapidly and catastrophically spread and highlighted significant limitations to our ability to control and treat infection. Thus, a basic understanding of entry and replication mechanisms of coronaviruses is necessary to rationally evaluate potential antivirals. Here, we show that polyamines, small metabolites synthesized in human cells, facilitate coronavirus replication and the depletion of polyamines with FDA-approved molecules significantly reduces coronavirus replication. We find that diverse coronaviruses, including endemic and epidemic coronaviruses, exhibit reduced attachment and entry into polyamine-depleted cells. We further demonstrate that several molecules targeting the polyamine biosynthetic pathway are antiviral in vitro. In sum, our data suggest that polyamines are critical to coronavirus replication and represent a highly promising drug target in the current and any future coronavirus outbreaks.
Collapse
Affiliation(s)
- Mason R. Firpo
- Department of Microbiology and Immunology, Loyola University Chicago, Stritch School of Medicine, Maywood, IL 60153, USA
| | - Vincent Mastrodomenico
- Department of Microbiology and Immunology, Loyola University Chicago, Stritch School of Medicine, Maywood, IL 60153, USA
| | - Grant M. Hawkins
- Department of Microbiology and Immunology, Loyola University Chicago, Stritch School of Medicine, Maywood, IL 60153, USA
| | - Matthieu Prot
- G5 Evolutionary Genomics of RNA Viruses, Institut Pasteur, Paris 75015, France
| | - Laura Levillayer
- Functional Genetics of Infectious diseases Unit, Institut Pasteur, Paris 75015, France
| | - Thomas Gallagher
- Department of Microbiology and Immunology, Loyola University Chicago, Stritch School of Medicine, Maywood, IL 60153, USA
| | | | - Bryan C. Mounce
- Department of Microbiology and Immunology, Loyola University Chicago, Stritch School of Medicine, Maywood, IL 60153, USA
| |
Collapse
|
10
|
van de Berg D, Kis Z, Behmer CF, Samnuan K, Blakney AK, Kontoravdi C, Shattock R, Shah N. Quality by design modelling to support rapid RNA vaccine production against emerging infectious diseases. NPJ Vaccines 2021; 6:65. [PMID: 33927197 PMCID: PMC8085199 DOI: 10.1038/s41541-021-00322-7] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Accepted: 03/07/2021] [Indexed: 12/21/2022] Open
Abstract
Rapid-response vaccine production platform technologies, including RNA vaccines, are being developed to combat viral epidemics and pandemics. A key enabler of rapid response is having quality-oriented disease-agnostic manufacturing protocols ready ahead of outbreaks. We are the first to apply the Quality by Design (QbD) framework to enhance rapid-response RNA vaccine manufacturing against known and future viral pathogens. This QbD framework aims to support the development and consistent production of safe and efficacious RNA vaccines, integrating a novel qualitative methodology and a quantitative bioprocess model. The qualitative methodology identifies and assesses the direction, magnitude and shape of the impact of critical process parameters (CPPs) on critical quality attributes (CQAs). The mechanistic bioprocess model quantifies and maps the effect of four CPPs on the CQA of effective yield of RNA drug substance. Consequently, the first design space of an RNA vaccine synthesis bioreactor is obtained. The cost-yield optimization together with the probabilistic design space contribute towards automation of rapid-response, high-quality RNA vaccine production.
Collapse
Affiliation(s)
- Damien van de Berg
- Centre for Process Systems Engineering, Department of Chemical Engineering, Faculty of Engineering, Imperial College London, London, UK
| | - Zoltán Kis
- Centre for Process Systems Engineering, Department of Chemical Engineering, Faculty of Engineering, Imperial College London, London, UK
| | - Carl Fredrik Behmer
- Centre for Process Systems Engineering, Department of Chemical Engineering, Faculty of Engineering, Imperial College London, London, UK
| | - Karnyart Samnuan
- Department of Infectious Disease, Faculty of Medicine, Imperial College London, London, UK
| | - Anna K Blakney
- Department of Infectious Disease, Faculty of Medicine, Imperial College London, London, UK
- University of British Columbia, Michael Smith Laboratories and School of Biomedical Engineering, Vancouver, BC, Canada
| | - Cleo Kontoravdi
- Centre for Process Systems Engineering, Department of Chemical Engineering, Faculty of Engineering, Imperial College London, London, UK
| | - Robin Shattock
- Department of Infectious Disease, Faculty of Medicine, Imperial College London, London, UK
| | - Nilay Shah
- Centre for Process Systems Engineering, Department of Chemical Engineering, Faculty of Engineering, Imperial College London, London, UK.
| |
Collapse
|
11
|
Tulluri V, Nemmara VV. Role of Antizyme Inhibitor Proteins in Cancers and Beyond. Onco Targets Ther 2021; 14:667-682. [PMID: 33531815 PMCID: PMC7846877 DOI: 10.2147/ott.s281157] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Accepted: 11/05/2020] [Indexed: 01/30/2023] Open
Abstract
Polyamines are multivalent organic cations essential for many cellular functions, including cell growth, differentiation, and proliferation. However, elevated polyamine levels are associated with a slew of pathological conditions, including multiple cancers. Intracellular polyamine levels are primarily controlled by the autoregulatory circuit comprising two different protein types, Antizymes (OAZ) and Antizyme Inhibitors (AZIN), which regulate the activity of the polyamine biosynthetic enzyme ornithine decarboxylase (ODC). While OAZ functions to decrease the intracellular polyamine levels by inhibiting ODC activity and exerting a negative control of polyamine uptake, AZIN operates to increase intracellular polyamine levels by binding and sequestering OAZ to relieve ODC inhibition and to increase polyamine uptake. Interestingly, OAZ and AZIN exhibit autoregulatory functions on polyamine independent pathways as well. A growing body of evidence demonstrates the dysregulation of AZIN expression in multiple cancers. Additionally, RNA editing of the Azin1 transcript results in a "gain-of-function" phenotype, which is shown to drive aggressive tumor types. This review will discuss the recent advances in AZIN's role in cancers via aberrant polyamine upregulation and its polyamine-independent protein regulation. This report will also highlight AZIN interaction with proteins outside the polyamine biosynthetic pathway and its potential implication to cancer pathogenesis. Finally, this review will reveal the protein interaction network of AZIN isoforms by analyzing three different interactome databases.
Collapse
Affiliation(s)
- Vennela Tulluri
- Department of Chemistry and Biochemistry, Rowan University, Glassboro, NJ08028, USA
| | - Venkatesh V Nemmara
- Department of Chemistry and Biochemistry, Rowan University, Glassboro, NJ08028, USA
| |
Collapse
|
12
|
Woo J, Kim JH, Kim S, Park KS. Promoter engineering improves transcription efficiency in biomolecular assays. Chem Commun (Camb) 2021; 57:1619-1622. [PMID: 33458724 DOI: 10.1039/d0cc07797f] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We identified a novel 12 bp promoter that significantly increased transcription efficiency. Unlike the standard 20 bp promoter, which contains both recognition and initiation regions, the new promoter contains only a recognition region and is more suitable for diagnostic applications due to its smaller size. This promoter effectively produced different light-up RNA aptamers via transcription. Moreover, we used the promoter to analyze RNase H activity and achieved a detection limit of 0.009 U mL-1, which was significantly better than that achieved via previous methods. We propose that the new promoter may serve as a key component in various diagnostic applications.
Collapse
Affiliation(s)
- Jisu Woo
- Department of Biological Engineering, College of Engineering, Konkuk University, Seoul 05029, Republic of Korea.
| | | | | | | |
Collapse
|
13
|
Kartje ZJ, Janis HI, Mukhopadhyay S, Gagnon KT. Revisiting T7 RNA polymerase transcription in vitro with the Broccoli RNA aptamer as a simplified real-time fluorescent reporter. J Biol Chem 2020; 296:100175. [PMID: 33303627 PMCID: PMC7948468 DOI: 10.1074/jbc.ra120.014553] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Revised: 12/03/2020] [Accepted: 12/10/2020] [Indexed: 11/06/2022] Open
Abstract
Methods for rapid and high-throughput screening of transcription in vitro to examine reaction conditions, enzyme mutants, promoter variants, and small molecule modulators can be extremely valuable tools. However, these techniques may be difficult to establish or inaccessible to many researchers. To develop a straightforward and cost-effective platform for assessing transcription in vitro, we used the "Broccoli" RNA aptamer as a direct, real-time fluorescent transcript readout. To demonstrate the utility of our approach, we screened the effect of common reaction conditions and components on bacteriophage T7 RNA polymerase (RNAP) activity using a common quantitative PCR instrument for fluorescence detection. Several essential conditions for in vitro transcription by T7 RNAP were confirmed with this assay, including the importance of enzyme and substrate concentrations, covariation of magnesium and nucleoside triphosphates, and the effects of several typical additives. When we used this method to assess all possible point mutants of a canonical T7 RNAP promoter, our results coincided well with previous reports. This approach should translate well to a broad variety of bacteriophage in vitro transcription systems and provides a platform for developing fluorescence-based readouts of more complex transcription systems in vitro.
Collapse
Affiliation(s)
- Zachary J Kartje
- Department of Chemistry and Biochemistry, Southern Illinois University, Carbondale, Illinois, USA
| | - Helen I Janis
- Department of Chemistry and Biochemistry, Southern Illinois University, Carbondale, Illinois, USA
| | - Shaoni Mukhopadhyay
- Department of Biochemistry and Molecular Biology, Southern Illinois University School of Medicine, Carbondale, Illinois, USA
| | - Keith T Gagnon
- Department of Chemistry and Biochemistry, Southern Illinois University, Carbondale, Illinois, USA; Department of Biochemistry and Molecular Biology, Southern Illinois University School of Medicine, Carbondale, Illinois, USA.
| |
Collapse
|
14
|
Mastrodomenico V, Esin JJ, Qazi S, Khomutov MA, Ivanov AV, Mukhopadhyay S, Mounce BC. Virion-Associated Polyamines Transmit with Bunyaviruses to Maintain Infectivity and Promote Entry. ACS Infect Dis 2020; 6:2490-2501. [PMID: 32687697 DOI: 10.1021/acsinfecdis.0c00402] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Viruses require host cell metabolites to productively infect, and the mechanisms by which viruses usurp these molecules are diverse. One group of cellular metabolites important in virus infection is the polyamines, small positively charged molecules involved in cell cycle, translation, and nucleic acid metabolism, among other cellular functions. Polyamines support replication of diverse viruses, and they are important for processes such as transcription, translation, and viral protein enzymatic activity. Rift Valley fever virus (RVFV) is a negative and ambisense RNA virus that requires polyamines to produce infectious particles. In polyamine depleted conditions, noninfectious particles are produced that interfere with virus replication and stimulate immune signaling. Here, we find that RVFV relies on virion-associated polyamines to maintain infectivity and enhance viral entry. We show that RVFV replication is facilitated by a limited set of polyamines and that spermidine and closely related molecules associate with purified virions and transmit from cell to cell during infection. Virion-associated spermidine maintains virion infectivity, as virions devoid of polyamines rapidly lose infectivity and are temperature sensitive. Further, virions without polyamines bind to cells but exhibit a defect in entry, requiring more acidic conditions than virions containing spermidine. These data highlight a unique role for polyamines, and spermidine particularly, to maintain virus infectivity. Further, these studies are the first to identify polyamines associated with RVFV virions. Targeting polyamines represents a promising antiviral strategy, and this work highlights a new mechanism by which we can inhibit virus replication through FDA-approved polyamine depleting pharmaceuticals.
Collapse
Affiliation(s)
- Vincent Mastrodomenico
- Department of Microbiology and Immunology, Stritch School of Medicine, Loyola University Chicago, Maywood, Illinois 60153, United States
| | - Jeremy J. Esin
- Department of Microbiology and Immunology, Stritch School of Medicine, Loyola University Chicago, Maywood, Illinois 60153, United States
- Infectious Disease and Immunology Research Institute, Stritch School of Medicine, Loyola University Chicago, Maywood, Illinois 60153, United States
| | - Shefah Qazi
- Department of Biology, Indiana University, Bloomington, Indiana 47405, United States
| | - Maxim A. Khomutov
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Moscow 119991, Russia
| | - Alexander V. Ivanov
- Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Moscow 119991, Russia
| | | | - Bryan C. Mounce
- Department of Microbiology and Immunology, Stritch School of Medicine, Loyola University Chicago, Maywood, Illinois 60153, United States
- Infectious Disease and Immunology Research Institute, Stritch School of Medicine, Loyola University Chicago, Maywood, Illinois 60153, United States
| |
Collapse
|
15
|
Firpo MR, Mounce BC. Diverse Functions of Polyamines in Virus Infection. Biomolecules 2020; 10:E628. [PMID: 32325677 PMCID: PMC7226272 DOI: 10.3390/biom10040628] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2020] [Revised: 04/10/2020] [Accepted: 04/15/2020] [Indexed: 12/11/2022] Open
Abstract
As obligate intracellular parasites, viruses rely on host cells for the building blocks of progeny viruses. Metabolites such as amino acids, nucleotides, and lipids are central to viral proteins, genomes, and envelopes, and the availability of these molecules can restrict or promote infection. Polyamines, comprised of putrescine, spermidine, and spermine in mammalian cells, are also critical for virus infection. Polyamines are small, positively charged molecules that function in transcription, translation, and cell cycling. Initial work on the function of polyamines in bacteriophage infection illuminated these molecules as critical to virus infection. In the decades since early virus-polyamine descriptions, work on diverse viruses continues to highlight a role for polyamines in viral processes, including genome packaging and viral enzymatic activity. On the host side, polyamines function in the response to virus infection. Thus, viruses and hosts compete for polyamines, which are a critical resource for both. Pharmacologically targeting polyamines, tipping the balance to favor the host and restrict virus replication, holds significant promise as a broad-spectrum antiviral strategy.
Collapse
Affiliation(s)
| | - Bryan C. Mounce
- Department of Microbiology and Immunology, Stritch School of Medicine, Loyola University Chicago, Maywood, IL 60153, USA;
| |
Collapse
|
16
|
Polyamine Depletion Abrogates Enterovirus Cellular Attachment. J Virol 2019; 93:JVI.01054-19. [PMID: 31341056 DOI: 10.1128/jvi.01054-19] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2019] [Accepted: 07/18/2019] [Indexed: 12/24/2022] Open
Abstract
Polyamines are small polycationic molecules with flexible carbon chains that are found in all eukaryotic cells. Polyamines are involved in the regulation of many host processes and have been shown to be implicated in viral replication. Depletion of polyamine pools in cells treated with FDA-approved drugs restricts replication of diverse RNA viruses. Viruses can exploit host polyamines to facilitate nucleic acid packaging, transcription, and translation, but other mechanisms remain largely unknown. Picornaviruses, including Coxsackievirus B3 (CVB3), are sensitive to the depletion of polyamines and remain a significant public health threat. We employed CVB3 as a model system to investigate a potential proviral role for polyamines using a forward screen. Passaging CVB3 in polyamine-depleted cells generated a mutation in capsid protein VP3 at residue 234. We show that this mutation confers resistance to polyamine depletion. Through attachment assays, we demonstrate that polyamine depletion limits CVB3 attachment to susceptible cells, which is rescued by incubating virus with polyamines. Furthermore, the capsid mutant rescues this inhibition in polyamine-depleted cells. More divergent viruses also exhibited reduced attachment to polyamine-depleted cells, suggesting that polyamines may facilitate attachment of diverse RNA viruses. These studies inform additional mechanisms of action for polyamine-depleting pharmaceuticals, with implications for potential antiviral therapies.IMPORTANCE Enteroviruses are significant human pathogens that can cause severe disease. These viruses rely on polyamines, small positively charged molecules, for robust replication, and polyamine depletion limits infection in vitro and in vivo The mechanisms by which polyamines enhance enteroviral replication are unknown. Here, we describe how Coxsackievirus B3 (CVB3) utilizes polyamines to attach to susceptible cells and initiate infection. Using a forward genetic screen, we identified a mutation in a receptor-binding amino acid that promotes infection of polyamine-depleted cells. These data suggest that pharmacologically inhibiting polyamine biosynthesis may combat virus infection by preventing virus attachment to susceptible cells.
Collapse
|
17
|
Taie HAA, Seif El-Yazal MA, Ahmed SMA, Rady MM. Polyamines modulate growth, antioxidant activity, and genomic DNA in heavy metal-stressed wheat plant. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2019; 26:22338-22350. [PMID: 31154641 DOI: 10.1007/s11356-019-05555-7] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2019] [Revised: 04/26/2019] [Accepted: 05/22/2019] [Indexed: 05/25/2023]
Abstract
A pot experiment was performed to assess the useful effects of seed soaking or seedling foliar spray using 0.25 mM spermine (Spm), 0.50 mM spermidine (Spd), or 1 mM putrescine (Put) on heavy metal tolerance in wheat plants irrigated with water contaminated by cadmium (2 mM Cd2+ in CdCl2) or lead (2 mM Pb2+ in PbCl2). Cd2+ or Pb2+ presence in the growth medium resulted in significant reductions in growth and yield characteristics and activities of leaf peroxidase (POD), glutathione reductase (GR), ascorbic acid oxidase (AAO), and polyphenol oxidase (PPO) of wheat plants. In contrast, significant increases were observed for Cd2+ content in roots, leaves and grains, superoxide dismutase (SOD) and catalase (CAT) activities, radical scavenging activity (DPPH), reducing power capacity, and fragmentation in DNA in comparison to controls (without Cd2+ or Pb2+ addition). However, treating the Cd2+- or Pb2+-stressed wheat plants with Spm, Spd, or Put, either by seed soaking or foliar spray, significantly improved growth and yield characteristics and activities of POD, GR, AAO, PPO, SOD, and CAT, DPPH, and reducing power capacity in wheat plants. In contrast, Cd2+ levels in roots, leaves, and yielded grains, and fragmentation in DNA were significantly reduced compared with the stressed (with Cd2+ or Pb2+) controls. Generally, seed soaking treatments were more effective than foliar spray treatments. More specifically, seed priming in Put was the best treatment under heavy metal stress. Results of this study recommend using polyamines, especially Put, as seed soaking to relieve the adverse effects of heavy metals in wheat plants.
Collapse
Affiliation(s)
- Hanan A A Taie
- Plant Biochemistry Department, National Research Centre, 33 Bohouth Street, Dokki, Cairo, Egypt
| | | | - Safia M A Ahmed
- Botany Department, Faculty of Agriculture, Fayoum University, Fayoum, 63514, Egypt
| | - Mostafa M Rady
- Botany Department, Faculty of Agriculture, Fayoum University, Fayoum, 63514, Egypt.
| |
Collapse
|
18
|
Polyamine Depletion Inhibits Bunyavirus Infection via Generation of Noninfectious Interfering Virions. J Virol 2019; 93:JVI.00530-19. [PMID: 31043534 DOI: 10.1128/jvi.00530-19] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2019] [Accepted: 04/28/2019] [Indexed: 12/24/2022] Open
Abstract
Several host and viral processes contribute to forming infectious virions. Polyamines are small host molecules that play diverse roles in viral replication. We previously demonstrated that polyamines are crucial for RNA viruses; however, the mechanisms by which polyamines function remain unknown. Here, we investigated the role of polyamines in the replication of the bunyaviruses Rift Valley fever virus (vaccine strain MP-12) and La Crosse virus (LACV). We found that polyamine depletion did not impact viral RNA or protein accumulation, despite significant decreases in titer. Viral particles demonstrated no change in morphology, size, or density. Thus, polyamine depletion promotes the formation of noninfectious particles. These particles interfere with virus replication and stimulate innate immune responses. We extended this phenotype to Zika virus; however, coxsackievirus did not similarly produce noninfectious particles. In sum, polyamine depletion results in the accumulation of noninfectious particles that interfere with replication and stimulate immune signaling, with important implications for targeting polyamines therapeutically, as well as for vaccine strategies.IMPORTANCE Bunyaviruses are emerging viral pathogens that cause encephalitis, hemorrhagic fevers, and meningitis. We have uncovered that diverse bunyaviruses require polyamines for productive infection. Polyamines are small, positively charged host-derived molecules that play diverse roles in human cells and in infection. In polyamine-depleted cells, bunyaviruses produce an overabundance of noninfectious particles that are indistinguishable from infectious particles. However, these particles interfere with productive infection and stimulate antiviral signaling pathways. We further find that additional enveloped viruses are similarly sensitive to polyamine depletion but that a nonenveloped enterovirus is not. We posit that polyamines are required to maintain bunyavirus infectivity and that polyamine depletion results in the accumulation of interfering noninfectious particles that limit infectivity. These results highlight a novel means by which bunyaviruses use polyamines for replication and suggest promising means to target host polyamines to reduce virus replication.
Collapse
|
19
|
Branched-chain polyamine stabilizes RNA polymerase at elevated temperatures in hyperthermophiles. Amino Acids 2019; 52:275-285. [PMID: 31101997 DOI: 10.1007/s00726-019-02745-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2019] [Accepted: 05/10/2019] [Indexed: 10/26/2022]
Abstract
Branched-chain polyamines (BCPAs) are unique polycations found in (hyper)thermophiles. Thermococcus kodakarensis grows optimally at 85 °C and produces the BCPA N4-bis(aminopropyl)spermidine by sequential addition of decarboxylated S-adenosylmethionine (dcSAM) aminopropyl groups to spermidine (SPD) by BCPA synthase A (BpsA). The T. kodakarensis bpsA deletion mutant (DBP1) did not grow at temperatures at or above 93 °C, and grew at 90 °C only after a long lag period following accumulation of excess cytoplasmic SPD. This suggests that BCPA plays an essential role in cell growth at higher temperatures and raises the possibility that BCPA is involved in controlling gene expression. To examine the effects of BCPA on transcription, the RNA polymerase (RNAP) core fraction was extracted from another bpsA deletion mutant, DBP4 (RNAPDBP4), which carried a His-tagged rpoL, and its enzymatic properties were compared with those of RNAP from wild-type (WT) cells (RNAPWT). LC-MS analysis revealed that nine ribosomal proteins were detected from RNAPWT but only one form RNAPDBP4. These results suggest that BCPA increases the linkage between RNAP and ribosomes to achieve efficient coupling of transcription and translation. Both RNAPs exhibited highest transcription activity in vitro at 80 °C, but the specific activity of RNAPDBP4 was lower than that of RNAPWT. Upon addition of SPD and BCPA, both increased the transcriptional activity of RNAPDBP4; however, elevation by BCPA was achieved at a tenfold lower concentration. Addition of BCPA also protected RNAPDBP4 against thermal inactivation at 90 °C. These results suggest that BCPA increases transcriptional activity in T. kodakarensis by stabilizing the RNAP complex at high temperatures.
Collapse
|
20
|
Dial CN, Tate PM, Kicmal TM, Mounce BC. Coxsackievirus B3 Responds to Polyamine Depletion via Enhancement of 2A and 3C Protease Activity. Viruses 2019; 11:E403. [PMID: 31052199 PMCID: PMC6563312 DOI: 10.3390/v11050403] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Revised: 04/26/2019] [Accepted: 04/26/2019] [Indexed: 01/16/2023] Open
Abstract
Polyamines are small positively-charged molecules abundant in eukaryotic cells that are crucial to RNA virus replication. In eukaryotic cells, polyamines facilitate processes such as transcription, translation, and DNA replication, and viruses similarly rely on polyamines to facilitate transcription and translation. Whether polyamines function at additional stages in viral replication remains poorly understood. Picornaviruses, including Coxsackievirus B3 (CVB3), are sensitive to polyamine depletion both in vitro and in vivo; however, precisely how polyamine function in picornavirus infection has not been described. Here, we describe CVB3 mutants that arise with passage in polyamine-depleted conditions. We observe mutations in the 2A and 3C proteases, and we find that these mutant proteases confer resistance to polyamine depletion. Using a split luciferase reporter system to measure protease activity, we determined that polyamines facilitate viral protease activity. We further observe that the 2A and 3C protease mutations enhance reporter protease activity in polyamine-depleted conditions. Finally, we find that these mutations promote cleavage of cellular eIF4G during infection of polyamine-depleted cells. In sum, our results suggest that polyamines are crucial to protease function during picornavirus infection. Further, these data highlight viral proteases as potential antiviral targets and highlight how CVB3 may overcome polyamine-depleting antiviral therapies.
Collapse
Affiliation(s)
- Courtney N Dial
- Department of Microbiology and Immunology, Stritch School of Medicine, Loyola University Chicago, Maywood, IL 60153, USA.
- Infectious Disease and Immunology Research Institute, Stritch School of Medicine, Loyola University Chicago, Maywood, IL 60153, USA.
| | - Patrick M Tate
- Department of Microbiology and Immunology, Stritch School of Medicine, Loyola University Chicago, Maywood, IL 60153, USA.
| | - Thomas M Kicmal
- Department of Microbiology and Immunology, Stritch School of Medicine, Loyola University Chicago, Maywood, IL 60153, USA.
- Infectious Disease and Immunology Research Institute, Stritch School of Medicine, Loyola University Chicago, Maywood, IL 60153, USA.
| | - Bryan C Mounce
- Department of Microbiology and Immunology, Stritch School of Medicine, Loyola University Chicago, Maywood, IL 60153, USA.
- Infectious Disease and Immunology Research Institute, Stritch School of Medicine, Loyola University Chicago, Maywood, IL 60153, USA.
| |
Collapse
|
21
|
Li CC, Wang XJ, Wang HCR. Repurposing host-based therapeutics to control coronavirus and influenza virus. Drug Discov Today 2019; 24:726-736. [PMID: 30711575 PMCID: PMC7108273 DOI: 10.1016/j.drudis.2019.01.018] [Citation(s) in RCA: 51] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2018] [Revised: 01/11/2019] [Accepted: 01/28/2019] [Indexed: 12/11/2022]
Abstract
Drug repositioning is a cost- and time-efficient approach for new indications. Targeting host machineries, used by viruses, could develop broad-spectrum antivirals. Repurposing existing drugs could efficiently identify antiviral agents.
The development of highly effective antiviral agents has been a major objective in virology and pharmaceutics. Drug repositioning has emerged as a cost-effective and time-efficient alternative approach to traditional drug discovery and development. This new shift focuses on the repurposing of clinically approved drugs and promising preclinical drug candidates for the therapeutic development of host-based antiviral agents to control diseases caused by coronavirus and influenza virus. Host-based antiviral agents target host cellular machineries essential for viral infections or innate immune responses to interfere with viral pathogenesis. This review discusses current knowledge, prospective applications and challenges in the repurposing of clinically approved and preclinically studied drugs for newly indicated antiviral therapeutics.
Collapse
Affiliation(s)
- Cui-Cui Li
- Key Laboratory of Animal Epidemiology of the Ministry of Agriculture, College of Veterinary Medicine, China Agricultural University, Beijing, China
| | - Xiao-Jia Wang
- Key Laboratory of Animal Epidemiology of the Ministry of Agriculture, College of Veterinary Medicine, China Agricultural University, Beijing, China.
| | - Hwa-Chain Robert Wang
- Department of Biomedical and Diagnostic Sciences, College of Veterinary Medicine, The University of Tennessee, Knoxville, USA.
| |
Collapse
|
22
|
Borkotoky S, Murali A. The highly efficient T7 RNA polymerase: A wonder macromolecule in biological realm. Int J Biol Macromol 2018; 118:49-56. [DOI: 10.1016/j.ijbiomac.2018.05.198] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2018] [Revised: 05/25/2018] [Accepted: 05/26/2018] [Indexed: 12/01/2022]
|
23
|
Arruabarrena-Aristorena A, Zabala-Letona A, Carracedo A. Oil for the cancer engine: The cross-talk between oncogenic signaling and polyamine metabolism. SCIENCE ADVANCES 2018; 4:eaar2606. [PMID: 29376126 PMCID: PMC5783676 DOI: 10.1126/sciadv.aar2606] [Citation(s) in RCA: 65] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2017] [Accepted: 12/28/2017] [Indexed: 05/09/2023]
Abstract
The study of metabolism has provided remarkable information about the biological basis and therapeutic weaknesses of cancer cells. Classic biochemistry established the importance of metabolic alterations in tumor biology and revealed the importance of various metabolite families to the tumorigenic process. We have evidence of the central role of polyamines, small polycatonic metabolites, in cell proliferation and cancer growth from these studies. However, how cancer cells activate this metabolic pathway and the molecular cues behind the oncogenic action of polyamines has remained largely obscure. In contrast to the view of metabolites as fuel (anabolic intermediates) for cancer cells, polyamines are better defined as the oil that lubricates the cancer engine because they affect the activity of biological processes. Modern research has brought back to the limelight this metabolic pathway, providing a strong link between genetic, metabolic, and signaling events in cancer. In this review, we enumerate and discuss current views of the regulation and activity of polyamine metabolism in tumor cell biology.
Collapse
Affiliation(s)
| | - Amaia Zabala-Letona
- CIC bioGUNE, Bizkaia Technology Park, 801A Building, 48160 Derio, Bizkaia, Spain
- CIBERONC Centro de Investigación Biomédica en Red de Cáncer, Avenida Monforte de Lemos, Madrid, Spain
| | - Arkaitz Carracedo
- CIC bioGUNE, Bizkaia Technology Park, 801A Building, 48160 Derio, Bizkaia, Spain
- CIBERONC Centro de Investigación Biomédica en Red de Cáncer, Avenida Monforte de Lemos, Madrid, Spain
- Ikerbasque, Basque Foundation for Science, 48011 Bilbao, Spain
- Biochemistry and Molecular Biology Department, University of the Basque Country (UPV/EHU), P.O. Box 644, E-48080 Bilbao, Spain
| |
Collapse
|
24
|
Mounce BC, Poirier EZ, Passoni G, Simon-Loriere E, Cesaro T, Prot M, Stapleford KA, Moratorio G, Sakuntabhai A, Levraud JP, Vignuzzi M. Interferon-Induced Spermidine-Spermine Acetyltransferase and Polyamine Depletion Restrict Zika and Chikungunya Viruses. Cell Host Microbe 2016; 20:167-77. [PMID: 27427208 DOI: 10.1016/j.chom.2016.06.011] [Citation(s) in RCA: 85] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2016] [Revised: 05/17/2016] [Accepted: 06/13/2016] [Indexed: 01/05/2023]
Abstract
Polyamines are small, positively charged molecules derived from ornithine and synthesized through an intricately regulated enzymatic pathway. Within cells, they are abundant and play several roles in diverse processes. We find that polyamines are required for the life cycle of the RNA viruses chikungunya virus (CHIKV) and Zika virus (ZIKV). Depletion of spermidine and spermine via type I interferon signaling-mediated induction of spermidine/spermine N1-acetyltransferase (SAT1), a key catabolic enzyme in the polyamine pathway, restricts CHIKV and ZIKV replication. Polyamine depletion restricts these viruses in vitro and in vivo, due to impairment of viral translation and RNA replication. The restriction is released by exogenous replenishment of polyamines, further supporting a role for these molecules in virus replication. Thus, SAT1 and, more broadly, polyamine depletion restrict viral replication and suggest promising avenues for antiviral therapies.
Collapse
Affiliation(s)
- Bryan C Mounce
- Viral Populations and Pathogenesis Unit, Institut Pasteur, CNRS UMR 3569, 25-28 rue du Dr. Roux, 75724 Paris Cedex 15, France
| | - Enzo Z Poirier
- Viral Populations and Pathogenesis Unit, Institut Pasteur, CNRS UMR 3569, 25-28 rue du Dr. Roux, 75724 Paris Cedex 15, France; University of Paris Diderot, Sorbonne Paris Cité, Cellule Pasteur, 75013 Paris, France
| | - Gabriella Passoni
- Virologie et Immunologie Moléculaire, INRA, Domaine de Vilvert, 78352 Jouy-en-Josas, France; Macrophages et Développement de l'Immunité, Institut Pasteur, 25-28 rue du Dr. Roux, 75724 Paris Cedex 15, France; CNRS URA2578, 75724 Paris Cedex 15, France
| | - Etienne Simon-Loriere
- Unité de Génétique Fonctionnelle des Maladies Infectieuses, Institut Pasteur, 25-28 rue du Dr. Roux, 75724 Paris Cedex 15, France
| | - Teresa Cesaro
- Viral Populations and Pathogenesis Unit, Institut Pasteur, CNRS UMR 3569, 25-28 rue du Dr. Roux, 75724 Paris Cedex 15, France
| | - Matthieu Prot
- Unité de Génétique Fonctionnelle des Maladies Infectieuses, Institut Pasteur, 25-28 rue du Dr. Roux, 75724 Paris Cedex 15, France
| | - Kenneth A Stapleford
- Viral Populations and Pathogenesis Unit, Institut Pasteur, CNRS UMR 3569, 25-28 rue du Dr. Roux, 75724 Paris Cedex 15, France
| | - Gonzalo Moratorio
- Viral Populations and Pathogenesis Unit, Institut Pasteur, CNRS UMR 3569, 25-28 rue du Dr. Roux, 75724 Paris Cedex 15, France
| | - Anavaj Sakuntabhai
- Unité de Génétique Fonctionnelle des Maladies Infectieuses, Institut Pasteur, 25-28 rue du Dr. Roux, 75724 Paris Cedex 15, France
| | - Jean-Pierre Levraud
- Macrophages et Développement de l'Immunité, Institut Pasteur, 25-28 rue du Dr. Roux, 75724 Paris Cedex 15, France; CNRS URA2578, 75724 Paris Cedex 15, France
| | - Marco Vignuzzi
- Viral Populations and Pathogenesis Unit, Institut Pasteur, CNRS UMR 3569, 25-28 rue du Dr. Roux, 75724 Paris Cedex 15, France.
| |
Collapse
|
25
|
Hu HT, Cho CP, Lin YH, Chang KY. A general strategy to inhibiting viral -1 frameshifting based on upstream attenuation duplex formation. Nucleic Acids Res 2015; 44:256-66. [PMID: 26612863 PMCID: PMC4705660 DOI: 10.1093/nar/gkv1307] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2015] [Accepted: 11/09/2015] [Indexed: 11/25/2022] Open
Abstract
Viral −1 programmed ribosomal frameshifting (PRF) as a potential antiviral target has attracted interest because many human viral pathogens, including human immunodeficiency virus (HIV) and coronaviruses, rely on −1 PRF for optimal propagation. Efficient eukaryotic −1 PRF requires an optimally placed stimulator structure downstream of the frameshifting site and different strategies targeting viral −1 PRF stimulators have been developed. However, accessing particular −1 PRF stimulator information represents a bottle-neck in combating the emerging epidemic viral pathogens such as Middle East respiratory syndrome coronavirus (MERS-CoV). Recently, an RNA hairpin upstream of frameshifting site was shown to act as a cis-element to attenuate −1 PRF with mechanism unknown. Here, we show that an upstream duplex formed in-trans, by annealing an antisense to its complementary mRNA sequence upstream of frameshifting site, can replace an upstream hairpin to attenuate −1 PRF efficiently. This finding indicates that the formation of a proximal upstream duplex is the main determining factor responsible for −1 PRF attenuation and provides mechanistic insight. Additionally, the antisense-mediated upstream duplex approach downregulates −1 PRF stimulated by distinct −1 PRF stimulators, including those of MERS-CoV, suggesting its general application potential as a robust means to evaluating viral −1 PRF inhibition as soon as the sequence information of an emerging human coronavirus is available.
Collapse
Affiliation(s)
- Hao-Teng Hu
- Institute of Biochemistry, National Chung-Hsing University, 250 Kuo-Kung Road, Taichung, 402 Taiwan
| | - Che-Pei Cho
- Institute of Biochemistry, National Chung-Hsing University, 250 Kuo-Kung Road, Taichung, 402 Taiwan
| | - Ya-Hui Lin
- Institute of Biochemistry, National Chung-Hsing University, 250 Kuo-Kung Road, Taichung, 402 Taiwan
| | - Kung-Yao Chang
- Institute of Biochemistry, National Chung-Hsing University, 250 Kuo-Kung Road, Taichung, 402 Taiwan
| |
Collapse
|
26
|
Hsu HT, Lin YH, Chang KY. Synergetic regulation of translational reading-frame switch by ligand-responsive RNAs in mammalian cells. Nucleic Acids Res 2014; 42:14070-82. [PMID: 25414357 PMCID: PMC4267651 DOI: 10.1093/nar/gku1233] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Distinct translational initiation mechanisms between prokaryotes and eukaryotes limit the exploitation of prokaryotic riboswitch repertoire for regulatory RNA circuit construction in mammalian application. Here, we explored programmed ribosomal frameshifting (PRF) as the regulatory gene expression platform for engineered ligand-responsive RNA devices in higher eukaryotes. Regulation was enabled by designed ligand-dependent conformational rearrangements of the two cis-acting RNA motifs of opposite activity in -1 PRF. Particularly, RNA elements responsive to trans-acting ligands can be tailored to modify co-translational RNA refolding dynamics of a hairpin upstream of frameshifting site to achieve reversible and adjustable -1 PRF attenuating activity. Combined with a ligand-responsive stimulator, synthetic RNA devices for synergetic translational-elongation control of gene expression can be constructed. Due to the similarity between co-transcriptional RNA hairpin folding and co-translational RNA hairpin refolding, the RNA-responsive ligand repertoire provided in prokaryotic systems thus becomes accessible to gene-regulatory circuit construction for synthetic biology application in mammalian cells.
Collapse
Affiliation(s)
- Hsiu-Ting Hsu
- Institute of Biochemistry, National Chung-Hsing University, 250 Kuo-Kung Road, Taichung 402, Taiwan
| | - Ya-Hui Lin
- Institute of Biochemistry, National Chung-Hsing University, 250 Kuo-Kung Road, Taichung 402, Taiwan
| | - Kung-Yao Chang
- Institute of Biochemistry, National Chung-Hsing University, 250 Kuo-Kung Road, Taichung 402, Taiwan
| |
Collapse
|
27
|
Cho CP, Lin SC, Chou MY, Hsu HT, Chang KY. Regulation of programmed ribosomal frameshifting by co-translational refolding RNA hairpins. PLoS One 2013; 8:e62283. [PMID: 23638024 PMCID: PMC3639245 DOI: 10.1371/journal.pone.0062283] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2012] [Accepted: 03/19/2013] [Indexed: 01/04/2023] Open
Abstract
RNA structures are unwound for decoding. In the process, they can pause the elongating ribosome for regulation. An example is the stimulation of -1 programmed ribosomal frameshifting, leading to 3′ direction slippage of the reading-frame during elongation, by specific pseudoknot stimulators downstream of the frameshifting site. By investigating a recently identified regulatory element upstream of the SARS coronavirus (SARS-CoV) −1 frameshifting site, it is shown that a minimal functional element with hairpin forming potential is sufficient to down-regulate−1 frameshifting activity. Mutagenesis to disrupt or restore base pairs in the potential hairpin stem reveals that base-pair formation is required for−1 frameshifting attenuation in vitro and in 293T cells. The attenuation efficiency of a hairpin is determined by its stability and proximity to the frameshifting site; however, it is insensitive to E site sequence variation. Additionally, using a dual luciferase assay, it can be shown that a hairpin stimulated +1 frameshifting when placed upstream of a +1 shifty site in yeast. The investigations indicate that the hairpin is indeed a cis-acting programmed reading-frame switch modulator. This result provides insight into mechanisms governing−1 frameshifting stimulation and attenuation. Since the upstream hairpin is unwound (by a marching ribosome) before the downstream stimulator, this study’s findings suggest a new mode of translational regulation that is mediated by the reformed stem of a ribosomal unwound RNA hairpin during elongation.
Collapse
Affiliation(s)
- Che-Pei Cho
- Institute of Biochemistry, National Chung-Hsing University, Taichung, Taiwan, Republic of China
| | - Szu-Chieh Lin
- Institute of Biochemistry, National Chung-Hsing University, Taichung, Taiwan, Republic of China
| | - Ming-Yuan Chou
- Institute of Biochemistry, National Chung-Hsing University, Taichung, Taiwan, Republic of China
| | - Hsiu-Ting Hsu
- Institute of Biochemistry, National Chung-Hsing University, Taichung, Taiwan, Republic of China
| | - Kung-Yao Chang
- Institute of Biochemistry, National Chung-Hsing University, Taichung, Taiwan, Republic of China
- * E-mail:
| |
Collapse
|
28
|
Wang SY, Lee YL, Lai YH, Chen JJW, Wu WL, Yuann JMP, Su WL, Chuang SM, Hou MH. Spermine attenuates the action of the DNA intercalator, actinomycin D, on DNA binding and the inhibition of transcription and DNA replication. PLoS One 2012; 7:e47101. [PMID: 23144800 PMCID: PMC3493566 DOI: 10.1371/journal.pone.0047101] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2012] [Accepted: 09/10/2012] [Indexed: 12/23/2022] Open
Abstract
The anticancer activity of DNA intercalators is related to their ability to intercalate into the DNA duplex with high affinity, thereby interfering with DNA replication and transcription. Polyamines (spermine in particular) are almost exclusively bound to nucleic acids and are involved in many cellular processes that require nucleic acids. Until now, the effects of polyamines on DNA intercalator activities have remained unclear because intercalation is the most important mechanism employed by DNA-binding drugs. Herein, using actinomycin D (ACTD) as a model, we have attempted to elucidate the effects of spermine on the action of ACTD, including its DNA-binding ability, RNA and DNA polymerase interference, and its role in the transcription and replication inhibition of ACTD within cells. We found that spermine interfered with the binding and stabilization of ACTD to DNA. The presence of increasing concentrations of spermine enhanced the transcriptional and replication activities of RNA and DNA polymerases, respectively, in vitro treated with ActD. Moreover, a decrease in intracellular polyamine concentrations stimulated by methylglyoxal-bis(guanylhydrazone) (MGBG) enhanced the ACTD-induced inhibition of c-myc transcription and DNA replication in several cancer cell lines. The results indicated that spermine attenuates ACTD binding to DNA and its inhibition of transcription and DNA replication both in vitro and within cells. Finally, a synergistic antiproliferative effect of MGBG and ACTD was observed in a cell viability assay. Our findings will be of significant relevance to future developments in combination with cancer therapy by enhancing the anticancer activity of DNA interactors through polyamine depletion.
Collapse
Affiliation(s)
- Sheng-Yu Wang
- Department of Life Science, National Chung Hsing University, Taichung, Taiwan
- Institute of Genomics and Bioinformatics, National Chung Hsing University, Taichung, Taiwan
| | - Yueh-Luen Lee
- National Institute of Cancer Research, National Health Research Institutes, Miaoli, Taiwan
| | - Yi-Hua Lai
- Institute of Biomedical Sciences, National Chung Hsing University, Taichung, Taiwan
| | - Jeremy J. W. Chen
- Institute of Biomedical Sciences, National Chung Hsing University, Taichung, Taiwan
| | - Wen-Lin Wu
- Institute of Genomics and Bioinformatics, National Chung Hsing University, Taichung, Taiwan
| | - Jeu-Ming P. Yuann
- Department of Biotechnology, Ming Chuan University, Taoyuan County, Taiwan
| | - Wang-Lin Su
- Department of Life Science, National Chung Hsing University, Taichung, Taiwan
| | - Show-Mei Chuang
- Institute of Biomedical Sciences, National Chung Hsing University, Taichung, Taiwan
| | - Ming-Hon Hou
- Department of Life Science, National Chung Hsing University, Taichung, Taiwan
- Institute of Genomics and Bioinformatics, National Chung Hsing University, Taichung, Taiwan
- * E-mail:
| |
Collapse
|
29
|
Chang YM, Chen CKM, Hou MH. Conformational changes in DNA upon ligand binding monitored by circular dichroism. Int J Mol Sci 2012; 13:3394-3413. [PMID: 22489158 PMCID: PMC3317384 DOI: 10.3390/ijms13033394] [Citation(s) in RCA: 134] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2012] [Revised: 02/22/2012] [Accepted: 02/24/2012] [Indexed: 11/16/2022] Open
Abstract
Circular dichroism (CD) spectroscopy is an optical technique that measures the difference in the absorption of left and right circularly polarized light. This technique has been widely employed in the studies of nucleic acids structures and the use of it to monitor conformational polymorphism of DNA has grown tremendously in the past few decades. DNA may undergo conformational changes to B-form, A-form, Z-form, quadruplexes, triplexes and other structures as a result of the binding process to different compounds. Here we review the recent CD spectroscopic studies of the induction of DNA conformational changes by different ligands, which includes metal derivative complex of aureolic family drugs, actinomycin D, neomycin, cisplatin, and polyamine. It is clear that CD spectroscopy is extremely sensitive and relatively inexpensive, as compared with other techniques. These studies show that CD spectroscopy is a powerful technique to monitor DNA conformational changes resulting from drug binding and also shows its potential to be a drug-screening platform in the future.
Collapse
Affiliation(s)
- Yu-Ming Chang
- Institute of Biological Chemistry, Academia Sinica, Taipei 115, Taiwan; E-Mails: (Y.-M.C.); (C.K.-M.C.)
| | - Cammy K.-M. Chen
- Institute of Biological Chemistry, Academia Sinica, Taipei 115, Taiwan; E-Mails: (Y.-M.C.); (C.K.-M.C.)
| | - Ming-Hon Hou
- Institute of Genomics and Bioinformatics, National Chung Hsing University, Taichung 402, Taiwan
| |
Collapse
|
30
|
Tokmakov AA, Fukami Y. Activation of T7 RNA polymerase in Xenopus oocytes and cell-free extracts. Genes Cells 2010; 15:1136-44. [PMID: 20977547 DOI: 10.1111/j.1365-2443.2010.01447.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Single-subunit bacteriophage T7 RNA polymerase (T7 RNAP) is universally employed for in vivo and in vitro transcription of genes put under control of the T7 promoter. The enzyme is capable of transcribing a complete gene without additional proteins. In this study, we reveal the presence of a low molecular weight factor, which induces several-fold activation of T7 RNAP in the cytoplasm of oocytes and eggs from Xenopus laevis. Cell-free reconstitution of the T7 RNAP activation allowed us to investigate the molecular properties of the activator, establish its peptide nature and suggest T7 RNAP activation mechanism. In contrast to the previously described nonspecific transcriptional activators, which interact with scattered ionic sites on nucleic acids, the peptide activator associates with T7 RNAP molecule, thus being a bona fide activator of the polymerase. To our knowledge, this is the first report concerning the specific activation of T7 RNAP by a factor of peptide or protein origin. Besides rather obvious merits in gaining more efficient transcription with T7 RNAP, this finding can provide additional insights into regulatory mechanisms of transcription. The study also introduces a novel highly sensitive luminescent assay of T7 RNAP activity.
Collapse
Affiliation(s)
- Alexander A Tokmakov
- Research Center for Environmental Genomics and Graduate School of Science, Kobe University, Nada, Kobe, Japan.
| | | |
Collapse
|
31
|
Abstract
RNA molecules are commonly produced in vitro by transcription, utilizing a DNA template, an RNA polymerase enzyme, and nucleoside triphosphate substrates (NTPs). In addition to the full-length RNA molecule coded for by the DNA template, significant amounts of shorter RNA molecules are produced. A simplified model of this complex transcription process is presented, with the shorter RNA molecules lumped into a single pool. The rate equations do not depend on the stoichiometry of the RNA molecule of interest, which facilitates application of the model to other RNA molecules. Optimal initial conditions for batch in vitro RNA transcription to produce a dodecamer RNA containing three different nucleotides have been predicted using the model. The predicted optimal values for equimolar NTPs are 10 to 15 mM initial concentration for each NTP and 50 to 60 mM for magnesium acetate, yielding a maximum final dodecamer concentration of 0.8 +/- 0.1 mM at the 90% confidence interval. Experimental data agree well with the model results. (c) 1997 John Wiley & Sons, Inc. Biotechnol Bioeng 56: 210-220, 1997.
Collapse
Affiliation(s)
- J S Young
- Department of Chemical Engineering, Engineering Center, ECCH111, Campus Box 424, University of Colorado, Boulder, Colorado 80309-0424, USA
| | | | | |
Collapse
|
32
|
Hayrapetyan A, Grosjean H, Helm M. Effect of a quaternary pentamine on RNA stabilization and enzymatic methylation. Biol Chem 2009; 390:851-61. [PMID: 19558320 DOI: 10.1515/bc.2009.096] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Extreme thermophiles produce unusually long polyamines, including the linear caldopentamine (Cdp) and the branched pentamine tetrakis(3-aminopropyl)-ammonium (Taa), with the latter containing a central quaternary ammonium moiety. Here we compare the interaction of these two pentamines with RNA by studying the heat denaturation, electrophoretic behavior, and ability of tRNA to be methylated in vitro by purified tRNA methyltransferases under various salt conditions. At concentrations in the micromolar range, branched Taa causes a considerable increase in the melting temperature (T(m)) of yeast tRNA(Phe) transcripts by >20 degrees C, which is significantly greater than stabilization by the linear Cdp. In non-denaturing gel electrophoresis, strong and specific binding to Taa, but not to Cdp, was clearly observed for tRNA(Phe). In both types of experiments, polyamines and monovalent metal ions competed for binding sites. Structural probing revealed no significant conformational changes in tRNA on Taa binding. In post-transcriptional in vitro methylation reactions, the formation of m(2)G/m(2)(2)G by the methyltransferase Trm1p and of m(1)A by TrmIp were not affected or only slightly stimulated by polyamines. In contrast, Taa specifically inhibited Trm4p-dependent formation of m(5)C only in tRNA(Phe), likely by occupying sites that are relevant to RNA recognition by the methyltransferase.
Collapse
Affiliation(s)
- Armine Hayrapetyan
- Institute of Pharmacy and Molecular Biotechnology, University of Heidelberg, Heidelberg, Germany
| | | | | |
Collapse
|
33
|
Xiong XQ, Liang F, Yang L, Wang XL, Zhou X, Zheng CY, Cao XP. Transcription-inhibition and antitumor activities of N-alkylated tetraazacyclododecanes. Chem Biodivers 2007; 4:2791-7. [PMID: 18081089 DOI: 10.1002/cbdv.200790228] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
A series of alkyl-substituted tetraazacyclododecane congeners were synthesized, and their antitumor activities towards human HeLa cells as well as their effect on the in vitro transcription with T7 RNA polymerase were investigated. A structure-activity-relationship (SAR) study identified the most-active congeners as those with medium alkyl-chain lengths. Three compounds, 5-7, were found to exhibit significant biological activities, with IC50 values towards HeLa cells in the low-micromolar range.
Collapse
Affiliation(s)
- Xiao-Qin Xiong
- College of Chemistry & Molecular Sciences, Wuhan University, Wuhan, Hubei 430072, PR China
| | | | | | | | | | | | | |
Collapse
|
34
|
Zinchenko AA, Luckel F, Yoshikawa K. Transcription of giant DNA complexed with cationic nanoparticles as a simple model of chromatin. Biophys J 2006; 92:1318-25. [PMID: 17142281 PMCID: PMC1783880 DOI: 10.1529/biophysj.106.094185] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
We prepared complexes of giant double-stranded DNA with cationic nanoparticles of 10-40 nm in diameter as an artificial model of chromatin and characterized the properties of changes in their higher-order conformation. We measured the changes in transcriptional activity that accompanied the DNA conformational transitions. Complete inhibition was found at excess concentrations of nanoparticles. In contrast, at intermediate stages of DNA binding with nanoparticles, the transcription activity of DNA survived, and this strongly depended on the size of the nanoparticles. For large nanoparticles of 40 nm, a decrease in transcriptional activity can be caused by the addition of only a small amount of nanoparticles. On the other hand, there was almost no inhibition of DNA transcriptional activity with the addition of small nanoparticles (10 nm) until very high concentrations, even under conditions that induced DNA compaction as revealed by single-DNA observation. At higher concentrations of 10-nm nanoparticles, DNA transcription activity decreased abruptly until it was completely inhibited. These results are discussed in relation to the actual size of the histone core, together with the mechanism of switching of transcriptional activity in eukaryotic cells.
Collapse
Affiliation(s)
- Anatoly A Zinchenko
- Graduate School of Science, Department of Physics, Kyoto University, Sakyo-ku, Kyoto 608-8501, Japan.
| | | | | |
Collapse
|
35
|
Hou MH, Lin SB, Yuann JM, Lin WC, Wang AH, Kan Ls L. Effects of polyamines on the thermal stability and formation kinetics of DNA duplexes with abnormal structure. Nucleic Acids Res 2001; 29:5121-8. [PMID: 11812845 PMCID: PMC97540 DOI: 10.1093/nar/29.24.5121] [Citation(s) in RCA: 76] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The effects of ions (i.e. Na+, Mg2+ and polyamines including spermidine and spermine) on the stability of various DNA oligonucleotides in solution were studied. These synthetic DNA molecules contained sequences that mimic various cellular DNA structures, such as duplexes, bulged loops, hairpins and/or mismatched base pairs. Melting temperature curves obtained from the ultraviolet spectroscopic experiments indicated that the effectiveness of the stabilization of cations on the duplex formation follows the order of spermine > spermidine > Mg2+ > Na+ > Tris-HCl buffer alone at pH 7.3. Circular dichroism spectra showed that salts and polyamines did not change the secondary structures of those DNA molecules under study. Surface plasmon resonance (SPR) observations suggested that the rates of duplex formation are independent of the kind of cations used or the structure of the duplexes. However, the rate constants of DNA duplex dissociation decrease in the same order when those cations are involved. The enhancement of the duplex stability by polyamines, especially spermine, can compensate for the instability caused by abnormal structures (e.g. bulged loops, hairpins or mismatches). The effects can be so great as to make the abnormal DNAs as stable as the perfect duplex, both kinetically and thermodynamically. Our results may suggest that the interconversion of various DNA structures can be accomplished readily in the presence of polyamine. This may be relevant in understanding the role of DNA polymorphism in cells.
Collapse
Affiliation(s)
- M H Hou
- Institute of Chemistry, Academia Sinica, Taipei, 115 Taiwan
| | | | | | | | | | | |
Collapse
|
36
|
Iwata M, Izawa M, Sasaki N, Nagumo Y, Sasabe H, Hayashizaki Y. T7 RNA polymerase activation and improvement of the transcriptional sequencing by polyamines. Bioorg Med Chem 2000; 8:2185-94. [PMID: 11003163 DOI: 10.1016/s0968-0896(00)00156-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We examined the possibility to improve the effectiveness of the in vitro transcription system using T7 RNA polymerase by coexistence with organic bases. The effect of the additives was evaluated by measuring the amount of RNA products in comparison with that of the control system (without additive). We found that four commercial bases and a series of ethylated polyamine analogues newly designed were active enhancers in the following activation order, 1,8-bis(ethylamino)octane > 1,8-octanediamine > 1,5-bis(ethylamino)pentane > cadaverine > 1,8-bis(ethylamino)-4-azaoctane > spermidine 1,18-bis(ethylamino)-5,14-diazaoctadecane > agmatine. It was shown that RNA products were corresponding, only in the presence of active enhancers, to the full length size of the template DNA, and that sequencing signals were enhanced by the presence of active enhancers with high fidelity so that the transcriptional sequencing was further refined to be a highly sensitive sequencing method from a small amount of linear dsDNA. These results suggest that T7 RNA polymerase was activated by the specific binding of the polyamine additive to produce RNA transcripts with fidelity to the template DNA. Therefore, it is expected that the transcriptional sequencing in the presence of active enhancers might be a powerful and sensitive method, in place of the prevalent DNA amplification method, for genomic science projects and clinical and practical gene diagnoses.
Collapse
Affiliation(s)
- M Iwata
- Biopolymer Physics Laboratory, The Institute of Physical and Chemical Research (RIKEN), Saitama, Japan.
| | | | | | | | | | | |
Collapse
|
37
|
Iwata M. Multi-Layer Macromonocyclic Polyamines. I. Molecular Design and Synthesis of Component Monocyclic Precursors. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 2000. [DOI: 10.1246/bcsj.73.693] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
|
38
|
Wank H, Clodi E, Wallis MG, Schroeder R. The antibiotic viomycin as a model peptide for the origin of the co-evolution of RNA and proteins. ORIGINS LIFE EVOL B 1999; 29:391-404. [PMID: 10472628 DOI: 10.1023/a:1006572028643] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Viomycin is an RNA-binding peptide antibiotic which inhibits prokaryotic protein synthesis and group I intron self-splicing. This antibiotic enhances the activity of the ribozyme derived from the Neurospora crassa VS RNA, and at sub-inhibitory concentrations it induces the formation of group I intron oligomers. Here, we address the question whether viomycin exerts specificity in the promotion of RNA-RNA interactions. In an in vitro selection experiment we tested the ability of viomycin to specifically select molecules out of an RNA pool. Group I intron RNA was incubated with a pool of random sequence RNA, or with a pool of RNA molecules which had previously been enriched for viomycin-binding RNAs. Viomycin was added in order to select viomycin-binding RNAs and to guide their interaction with the intron RNA resulting in recombinant molecules. Viomycin was indeed capable of specifically selecting RNA molecules which contain viomycin-binding sites promoting recombination. These results suggest that small peptides are able to play the role of selector molecules in a putative 'RNA World' launching the co-evolution of RNA and proteins into an 'RNA-protein World'.
Collapse
Affiliation(s)
- H Wank
- Institute of Microbiology and Genetics, University of Vienna, Austria
| | | | | | | |
Collapse
|
39
|
Fechter P, Rudinger J, Giegé R, Théobald-Dietrich A. Ribozyme processed tRNA transcripts with unfriendly internal promoter for T7 RNA polymerase: production and activity. FEBS Lett 1998; 436:99-103. [PMID: 9771901 DOI: 10.1016/s0014-5793(98)01096-5] [Citation(s) in RCA: 111] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
A limitation for a universal use of T7 RNA polymerase for in vitro tRNA transcription lies in the nature of the often unfavorable 5'-terminal sequence of the gene to be transcribed. To overcome this drawback, a hammerhead ribozyme sequence was introduced between a strong T7 RNA polymerase promoter and the tDNA sequence. Transcription of this construct gives rise to a 'transzyme' molecule, the autocatalytic activity of which liberates a 5'-OH tRNA transcript starting with the proper nucleotide. The method was optimized for transcription of yeast tRNA(Tgammar), starting with 5'-C1, and operates as well for yeast tRNA(Asp) with 5'-U1. Although the tRNAs produced by the transzyme method are not phosphorylated, they are fully active in aminoacylation with k(cat) and Km parameters quasi identical to those of their phosphorylated counterparts.
Collapse
MESH Headings
- Biochemistry/methods
- DNA-Directed RNA Polymerases/genetics
- DNA-Directed RNA Polymerases/metabolism
- Kinetics
- Promoter Regions, Genetic
- RNA, Catalytic/genetics
- RNA, Catalytic/metabolism
- RNA, Transfer, Tyr/chemistry
- RNA, Transfer, Tyr/genetics
- RNA, Transfer, Tyr/metabolism
- Transcription, Genetic
- Viral Proteins
Collapse
Affiliation(s)
- P Fechter
- UPR 9002 du CNRS, Institut de Biologie Moléculaire et Cellulaire, Strasbourg, France
| | | | | | | |
Collapse
|
40
|
Bielinska AU, Kukowska-Latallo JF, Baker JR. The interaction of plasmid DNA with polyamidoamine dendrimers: mechanism of complex formation and analysis of alterations induced in nuclease sensitivity and transcriptional activity of the complexed DNA. BIOCHIMICA ET BIOPHYSICA ACTA 1997; 1353:180-90. [PMID: 9294012 DOI: 10.1016/s0167-4781(97)00069-9] [Citation(s) in RCA: 152] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The application of synthetic vectors for gene transfer has potential advantages over virus-based systems. However, little is known about the mechanisms involved in binding of synthetic materials to DNA and the nature of the DNA complexes that result from this interaction. Polyamidoamine (PAMAM) dendrimers are unique polymers with defined spherical structure. Dendrimers bind DNA to form complexes that efficiently transfect cells in vitro. We examined the formation of DNA/dendrimer complexes and found it based entirely on charge interaction. Electronmicroscopic examination of the complexes indicated that the majority of the plasmid DNA is contracted into isolated toroids, but also revealed larger, irregular aggregates of polymer and DNA. The binding of plasmid DNA to dendrimer appears to alter the secondary and tertiary structure, but does not fragment the DNA or alter its primary structure. Complexed DNA is protected against degradation by either specific nucleases or cellular extracts containing nuclease activity. While the initiation of transcription in vitro from promoters (for either T7 polymerase or eukaryotic RNA polymerase II) in dendrimer-complexed DNA is inhibited, elongation of the RNA transcript and translation do not appear to be affected. These resemble alterations of the DNA function when complexed with naturally-occurring polycations like non-acetylated histones. However, DNA complexed to dendrimer appears to maintain transcriptional activity while histone complexes at similar charge ratios do not. These results elucidate some aspects of the interaction between PAMAM dendritic polymers and DNA, and could lead to improvements in the design of polymers or formation of DNA complexes that will increase the efficiency of non-viral gene transfer.
Collapse
Affiliation(s)
- A U Bielinska
- Department of Internal Medicine, University of Michigan Medical School, Ann Arbor 48109-0666, USA
| | | | | |
Collapse
|
41
|
Affiliation(s)
- V V Gurevich
- Sun Health Research Institute, Sun City, Arizona 85351, USA
| |
Collapse
|
42
|
Abstract
Growing interest in RNAs for biomedical, agricultural, and other applications has necessitated the development of methods for producing oligoribonucleotides in milligram, or larger, quantities. Recent research on in vitro transcription has focused on optimizing solution conditions and the use of immobilized templates. In the alternative area of organic chemical synthesis, significant effort has been channeled into improving coupling efficiencies and producing modified RNA analogs which retain activity but have higher stability than unmodified RNAs.
Collapse
Affiliation(s)
- R H Davis
- Department of Chemical Engineering, University of Colorado, Boulder 80309-0424, USA
| |
Collapse
|