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Kar S, Gardner EC, Javanmardi K, Boutz DR, Shroff R, Horton AP, Segall-Shapiro TH, Ellington AD, Gollihar J. Directed evolution of an orthogonal transcription engine for programmable gene expression in eukaryotes. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.09.25.614978. [PMID: 39386662 PMCID: PMC11463353 DOI: 10.1101/2024.09.25.614978] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 10/12/2024]
Abstract
T7 RNA polymerase has enabled orthogonal control of gene expression and recombinant protein production across diverse prokaryotic host chassis organisms for decades. However, the absence of 5' methyl guanosine caps on T7 RNAP derived transcripts has severely limited its utility and widespread adoption in eukaryotic systems. To address this shortcoming, we evolved a fusion enzyme combining T7 RNAP with the single subunit capping enzyme from African swine fever virus using Saccharomyces cerevisiae. We isolated highly active variants of this fusion enzyme, which exhibited roughly two orders of magnitude higher protein expression compared to the wild-type enzyme. We demonstrate the programmable control of gene expression using T7 RNAP-based genetic circuits in yeast and validate enhanced performance of these engineered variants in mammalian cells. This study presents a robust, orthogonal gene regulatory system applicable across diverse eukaryotic hosts, enhancing the versatility and efficiency of synthetic biology applications.
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Affiliation(s)
- Shaunak Kar
- Laboratory of Antibody Discovery and Accelerated Protein Therapeutics, Center for Infectious Diseases, Houston Methodist Research Institute and Department of Pathology and Genomic Medicine, Houston Methodist Hospital, Houston, TX, USA
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX, USA
- Authors contributed equally
| | - Elizabeth C. Gardner
- Department of Bioengineering, Rice University, Houston, TX, USA
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX, USA
- Authors contributed equally
| | - Kamyab Javanmardi
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX, USA
| | - Daniel R. Boutz
- Laboratory of Antibody Discovery and Accelerated Protein Therapeutics, Center for Infectious Diseases, Houston Methodist Research Institute and Department of Pathology and Genomic Medicine, Houston Methodist Hospital, Houston, TX, USA
| | - Raghav Shroff
- Laboratory of Antibody Discovery and Accelerated Protein Therapeutics, Center for Infectious Diseases, Houston Methodist Research Institute and Department of Pathology and Genomic Medicine, Houston Methodist Hospital, Houston, TX, USA
| | - Andrew P. Horton
- Laboratory of Antibody Discovery and Accelerated Protein Therapeutics, Center for Infectious Diseases, Houston Methodist Research Institute and Department of Pathology and Genomic Medicine, Houston Methodist Hospital, Houston, TX, USA
| | - Thomas H. Segall-Shapiro
- Laboratory of Antibody Discovery and Accelerated Protein Therapeutics, Center for Infectious Diseases, Houston Methodist Research Institute and Department of Pathology and Genomic Medicine, Houston Methodist Hospital, Houston, TX, USA
| | - Andrew D. Ellington
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX, USA
- Center for Systems and Synthetic Biology, The University of Texas at Austin, Austin, TX, USA
| | - Jimmy Gollihar
- Laboratory of Antibody Discovery and Accelerated Protein Therapeutics, Center for Infectious Diseases, Houston Methodist Research Institute and Department of Pathology and Genomic Medicine, Houston Methodist Hospital, Houston, TX, USA
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2
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Virak V, Nov P, Chen D, Zhang X, Guan J, Que D, Yan J, Hen V, Choeng S, Zhong C, Yang P. Exploring the impact of metabolites function on heart failure and coronary heart disease: insights from a Mendelian randomization (MR) study. AMERICAN JOURNAL OF CARDIOVASCULAR DISEASE 2024; 14:242-254. [PMID: 39309113 PMCID: PMC11410790 DOI: 10.62347/oqxz7740] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2024] [Accepted: 08/23/2024] [Indexed: 09/25/2024]
Abstract
BACKGROUND Heart failure (HF) and coronary heart disease (CHD) are major causes of morbidity and mortality worldwide. While traditional risk factors such as hypertension, diabetes, and smoking have been extensively studied, the role of metabolite functions in the development of these cardiovascular conditions has been less explored. This study employed a Mendelian randomization (MR) approach to investigate the impact of metabolite functions on HF and CHD. METHODS To assess the causal impacts of specific metabolite risk factors on HF and CHD, this study utilized genetic variants associated with these factors as instrumental variables. Comprehensive genetic and phenotypic data from diverse cohorts, including genome-wide association studies (GWAS) and cardiovascular disease registries, were incorporated into the research. RESULTS Our results encompass 61 metabolic cell phenotypes, with ten providing strong evidence of the influence of metabolite functions on the occurrence of HF and CHD. We found that elevated levels of erucate (22:1n9), lower levels of α-tocopherol, an imbalanced citrulline-to-ornithine ratio, elevated γ-glutamyl glycine levels, and elevated 7-methylguanine levels independently increased the risk of these cardiovascular conditions. These findings were consistent across different populations and robust to sensitivity analyses. CONCLUSION This MR study provides valuable insights into the influence of metabolite functions on HF and CHD. However, further investigation is needed to fully understand the precise mechanisms by which these metabolite factors contribute to the onset of these conditions. Such research could pave the way for the development of targeted therapeutic strategies.
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Affiliation(s)
- Vicheth Virak
- Department of Cardiology, Laboratory of Heart Center, Zhujiang Hospital, Southern Medical UniversityGuangzhou, Guangdong, The People’s Republic of China
| | - Pengkhun Nov
- Department of Radiation Oncology, Zhujiang Hospital, Southern Medical UniversityGuangzhou, Guangdong, People’s Republic of China
| | - Deshu Chen
- Department of Cardiology, Laboratory of Heart Center, Zhujiang Hospital, Southern Medical UniversityGuangzhou, Guangdong, The People’s Republic of China
| | - Xuwei Zhang
- Department of Cardiology, Laboratory of Heart Center, Zhujiang Hospital, Southern Medical UniversityGuangzhou, Guangdong, The People’s Republic of China
| | - Junjie Guan
- Department of Cardiology, Laboratory of Heart Center, Zhujiang Hospital, Southern Medical UniversityGuangzhou, Guangdong, The People’s Republic of China
| | - Dongdong Que
- Department of Cardiology, Laboratory of Heart Center, Zhujiang Hospital, Southern Medical UniversityGuangzhou, Guangdong, The People’s Republic of China
| | - Jing Yan
- Department of Cardiology, Laboratory of Heart Center, Zhujiang Hospital, Southern Medical UniversityGuangzhou, Guangdong, The People’s Republic of China
| | - Vanna Hen
- Department of Cardiology, Laboratory of Heart Center, Zhujiang Hospital, Southern Medical UniversityGuangzhou, Guangdong, The People’s Republic of China
| | - Senglim Choeng
- Department of Obstetrics and Gynaecology, Zhujiang Hospital, Southern Medical UniversityGuangzhou, Guangdong, People’s Republic of China
| | - Chongbin Zhong
- Department of Cardiology, Laboratory of Heart Center, Zhujiang Hospital, Southern Medical UniversityGuangzhou, Guangdong, The People’s Republic of China
| | - Pingzhen Yang
- Department of Cardiology, Laboratory of Heart Center, Zhujiang Hospital, Southern Medical UniversityGuangzhou, Guangdong, The People’s Republic of China
- Heart Center of Zhujiang Hospital, Guangdong Provincial Biomedical Engineering Technology Research Center for Cardiovascular DiseaseGuangzhou, Guangdong, The People’s Republic of China
- Heart Center of Zhujiang Hospital, Sino-Japanese Cooperation Platform for Translational Research in Heart FailureGuangzhou, Guangdong, The People’s Republic of China
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Hardy EC, Balcerowicz M. Untranslated yet indispensable-UTRs act as key regulators in the environmental control of gene expression. JOURNAL OF EXPERIMENTAL BOTANY 2024; 75:4314-4331. [PMID: 38394144 PMCID: PMC11263492 DOI: 10.1093/jxb/erae073] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2023] [Accepted: 02/22/2024] [Indexed: 02/25/2024]
Abstract
To survive and thrive in a dynamic environment, plants must continuously monitor their surroundings and adjust their development and physiology accordingly. Changes in gene expression underlie these developmental and physiological adjustments, and are traditionally attributed to widespread transcriptional reprogramming. Growing evidence, however, suggests that post-transcriptional mechanisms also play a vital role in tailoring gene expression to a plant's environment. Untranslated regions (UTRs) act as regulatory hubs for post-transcriptional control, harbouring cis-elements that affect an mRNA's processing, localization, translation, and stability, and thereby tune the abundance of the encoded protein. Here, we review recent advances made in understanding the critical function UTRs exert in the post-transcriptional control of gene expression in the context of a plant's abiotic environment. We summarize the molecular mechanisms at play, present examples of UTR-controlled signalling cascades, and discuss the potential that resides within UTRs to render plants more resilient to a changing climate.
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Affiliation(s)
- Emma C Hardy
- Division of Plant Sciences, University of Dundee at the James Hutton Institute, Dundee DD2 5DA, UK
| | - Martin Balcerowicz
- Division of Plant Sciences, University of Dundee at the James Hutton Institute, Dundee DD2 5DA, UK
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4
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Simoes-Barbosa A, Pinheiro J. Unconventional features in the transcription and processing of spliceosomal small nuclear RNAs in the protozoan parasite Trichomonas vaginalis. Int J Parasitol 2024; 54:257-266. [PMID: 38452964 DOI: 10.1016/j.ijpara.2024.03.001] [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: 11/27/2023] [Revised: 02/07/2024] [Accepted: 03/03/2024] [Indexed: 03/09/2024]
Abstract
Trichomonas vaginalis is a medically important protozoan parasite, and a deep-branching, evolutionarily divergent unicellular eukaryote that has conserved several key features of eukaryotic gene expression. Trichomonas vaginalis possesses a metazoan/plant-like capping apparatus, mRNAs with a cap 1 structure and spliceosomes containing the five small nuclear RNAs (snRNAs). However, in contrast to metazoan and plant snRNAs, the structurally conserved T. vaginalis snRNAs were initially identified as lacking the canonical guanosine cap nucleotide. To explain this unusual condition, we sought to investigate transcriptional and processing features of the spliceosomal snRNAs in this protist. Here, we show that T. vaginalis spliceosomal snRNA genes mostly lack typical eukaryotic promoters. In contrast to other eukaryotes, the putative TATA box in the T. vaginalis U6 snRNA gene was found to be dispensable for transcription or RNA polymerase selectivity. Moreover, U6 transcription in T. vaginalis was virtually insensitive to tagetitoxin compared with other cellular transcripts produced by the same RNA polymerase III. Most important and unexpected, snRNA transcription in T. vaginalis appears to bypass capping as we show that these transcripts retain their original 5'-triphosphate groups. In conclusion, transcription and processing of spliceosomal snRNAs in T. vaginalis deviate considerably from the conventional rules of other eukaryotes.
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Affiliation(s)
- Augusto Simoes-Barbosa
- School of Biological Sciences, Faculty of Science, University of Auckland, Auckland 1010, New Zealand.
| | - Jully Pinheiro
- School of Biological Sciences, Faculty of Science, University of Auckland, Auckland 1010, New Zealand
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5
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Al-Hawary SIS, Jasim SA, Hjazi A, Oghenemaro EF, Kaur I, Kumar A, Al-Ani AM, Alwaily ER, Redhee AH, Mustafa YF. Nucleic acid-based vaccine for ovarian cancer cells; bench to bedside. Cell Biochem Funct 2024; 42:e3978. [PMID: 38515237 DOI: 10.1002/cbf.3978] [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: 01/23/2024] [Revised: 02/27/2024] [Accepted: 03/04/2024] [Indexed: 03/23/2024]
Abstract
Ovarian cancer continues to be a difficult medical issue that affects millions of individuals worldwide. Important platforms for cancer immunotherapy include checkpoint inhibitors, chimeric antigen receptor T cells, bispecific antibodies, cancer vaccines, and other cell-based treatments. To avoid numerous infectious illnesses, conventional vaccinations based on synthetic peptides, recombinant subunit vaccines, and live attenuated and inactivated pathogens are frequently utilized. Vaccine manufacturing processes, however, are not entirely safe and carry a significant danger of contaminating living microorganisms. As a result, the creation of substitute vaccinations is required for both viral and noninfectious illnesses, including cancer. Recently, there has been testing of nucleic acid vaccines, or NAVs, as a cancer therapeutic. Tumor antigens (TAs) are genetically encoded by DNA and mRNA vaccines, which the host uses to trigger immune responses against ovarian cancer cells that exhibit the TAs. Despite being straightforward, safe, and easy to produce, NAVs are not currently thought to be an ideal replacement for peptide vaccines. Some obstacles to this strategy include selecting the appropriate therapeutic agents (TAs), inadequate immunogenicity, and the immunosuppressive characteristic of ovarian cancer. We focus on strategies that have been employed to increase NAVs' effectiveness in the fight against ovarian cancer in this review.
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Affiliation(s)
| | - Saade Abdalkareem Jasim
- Medical Laboratory Techniques Department, Al-maarif University College, Anbar, Iraq
- Biotechnology Department, College of Applied Science, Fallujah University, Fallujah, Iraq
| | - Ahmed Hjazi
- Department of Medical Laboratory, College of Applied Medical Sciences, Prince Sattam bin Abdulaziz University, Al-Kharj, Saudi Arabia
| | - Enwa Felix Oghenemaro
- Department of Pharmaceutical Microbiology, Faculty of Pharmacy, Delta State University, Abraka, Nigeria
| | - Irwanjot Kaur
- Department of Biotechnology and Genetics, Jain (Deemed-to-be) University, Bengaluru, Karnataka, India
- Department of Allied Healthcare and Sciences, Vivekananda Global University, Jaipur, Rajasthan, India
| | - Abhinav Kumar
- Department of Nuclear and Renewable Energy, Ural Federal University Named after The First President of Russia, Yekaterinburg, Russia
| | | | - Enas R Alwaily
- Microbiology Research Group, College of Pharmacy, Al-Ayen University, Thi-Qar, Iraq
| | - Ahmed Huseen Redhee
- Medical Laboratory Technique College, The Islamic University, Najaf, Iraq
- Medical Laboratory Technique College, The Islamic University of Al Diwaniyah, Al Diwaniyah, Iraq
- Medical Laboratory Technique College, The Islamic University of Babylon, Babylon, Iraq
| | - Yasser Fakri Mustafa
- Department of Pharmaceutical Chemistry, College of Pharmacy, University of Mosul, Mosul, Iraq
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Tsukamoto Y, Igarashi M, Kato H. Targeting cap1 RNA methyltransferases as an antiviral strategy. Cell Chem Biol 2024; 31:86-99. [PMID: 38091983 DOI: 10.1016/j.chembiol.2023.11.011] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2023] [Revised: 10/30/2023] [Accepted: 11/20/2023] [Indexed: 01/21/2024]
Abstract
Methylation is one of the critical modifications that regulates numerous biological processes. Guanine capping and methylation at the 7th position (m7G) have been shown to mature mRNA for increased RNA stability and translational efficiency. The m7G capped cap0 RNA remains immature and requires additional methylation at the first nucleotide (N1-2'-O-Me), designated as cap1, to achieve full maturation. This cap1 RNA with N1-2'-O-Me prevents its recognition by innate immune sensors as non-self. Viruses have also evolved various strategies to produce self-like capped RNAs with the N1-2'-O-Me that potentially evades the antiviral response and establishes an efficient replication. In this review, we focus on the importance of the presence of N1-2'-O-Me in viral RNAs and discuss the potential for drug development by targeting host and viral N1-2'-O-methyltransferases.
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Affiliation(s)
- Yuta Tsukamoto
- Institute of Cardiovascular Immunology, Medical Faculty, University Hospital Bonn, University of Bonn, Bonn, Germany
| | - Manabu Igarashi
- Division of Global Epidemiology, International Institute for Zoonosis Control, Hokkaido University, Sapporo, Japan; International Collaboration Unit, International Institute for Zoonosis Control, Hokkaido University, Sapporo, Hokkaido, Japan
| | - Hiroki Kato
- Institute of Cardiovascular Immunology, Medical Faculty, University Hospital Bonn, University of Bonn, Bonn, Germany.
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7
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Kataoka N. The Nuclear Cap-Binding Complex, a multitasking binding partner of RNA polymerase II transcripts. J Biochem 2023; 175:9-15. [PMID: 37830942 PMCID: PMC10771035 DOI: 10.1093/jb/mvad081] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2023] [Revised: 09/26/2023] [Accepted: 10/03/2023] [Indexed: 10/14/2023] Open
Abstract
In eukaryotic cells, RNAs transcribed by RNA polymerase-II receive the modification at the 5' end. This structure is called the cap structure. The cap structure has a fundamental role for translation initiation by recruiting eukaryotic translation initiation factor 4F (eIF4F). The other important mediator of the cap structure is a nuclear cap-binding protein complex (CBC). CBC consists of two proteins, which are renamed as NCBP1 and NCBP2 (previously called as CBP80/NCBP and CBP20/NIP1, respectively). This review article discusses the multiple roles CBC mediates and co-ordinates in several gene expression steps in eukaryotes.
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Affiliation(s)
- Naoyuki Kataoka
- Laboratory of Cellular Biochemistry, Department of Animal Resource Sciences, Graduate School of Agriculture and Life Sciences, The University of Tokyo, Agriculture Bldg. 7A, Room 703, Yayoi 1-1-1, Bunkyo-ku, Tokyo 113-8657, Japan
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8
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Yang D, Zhao G, Zhang HM. m 6A reader proteins: the executive factors in modulating viral replication and host immune response. Front Cell Infect Microbiol 2023; 13:1151069. [PMID: 37325513 PMCID: PMC10266107 DOI: 10.3389/fcimb.2023.1151069] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2023] [Accepted: 05/03/2023] [Indexed: 06/17/2023] Open
Abstract
N6-Methyladenosine (m6A) modification is the most abundant covalent modification of RNA. It is a reversible and dynamic process induced by various cellular stresses including viral infection. Many m6A methylations have been discovered, including on the genome of RNA viruses and on RNA transcripts of DNA viruses, and these methylations play a positive or negative role on the viral life cycle depending on the viral species. The m6A machinery, including the writer, eraser, and reader proteins, achieves its gene regulatory role by functioning in an orchestrated manner. Notably, data suggest that the biological effects of m6A on target mRNAs predominantly depend on the recognition and binding of different m6A readers. These readers include, but are not limited to, the YT521-B homology (YTH) domain family, heterogeneous nuclear ribonucleoproteins (HNRNPs), insulin-like growth factor 2 mRNA-binding proteins (IGF2BPs), and many others discovered recently. Indeed, m6A readers have been recognized not only as regulators of RNA metabolism but also as participants in a variety of biological processes, although some of these reported roles are still controversial. Here, we will summarize the recent advances in the discovery, classification, and functional characterization of m6A reader proteins, particularly focusing on their roles and mechanisms of action in RNA metabolism, gene expression, and viral replication. In addition, we also briefly discuss the m6A-associated host immune responses in viral infection.
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Affiliation(s)
- Decheng Yang
- Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, BC, Canada
- Centre for Heart Lung Innovation, St. Paul’s Hospital, Vancouver, BC, Canada
| | - Guangze Zhao
- Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, BC, Canada
- Centre for Heart Lung Innovation, St. Paul’s Hospital, Vancouver, BC, Canada
| | - Huifang Mary Zhang
- Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, BC, Canada
- Centre for Heart Lung Innovation, St. Paul’s Hospital, Vancouver, BC, Canada
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9
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Liang S, Almohammed R, Cowling VH. The RNA cap methyltransferases RNMT and CMTR1 co-ordinate gene expression during neural differentiation. Biochem Soc Trans 2023:233029. [PMID: 37145036 DOI: 10.1042/bst20221154] [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: 11/18/2022] [Revised: 04/03/2023] [Accepted: 04/18/2023] [Indexed: 05/06/2023]
Abstract
Regulation of RNA cap formation has potent impacts on gene regulation, controlling which transcripts are expressed, processed and translated into protein. Recently, the RNA cap methyltransferases RNA guanine-7 methyltransferase (RNMT) and cap-specific mRNA (nucleoside-2'-O-)-methyltransferase 1 (CMTR1) have been found to be independently regulated during embryonic stem (ES) cell differentiation controlling the expression of overlapping and distinct protein families. During neural differentiation, RNMT is repressed and CMTR1 is up-regulated. RNMT promotes expression of the pluripotency-associated gene products; repression of the RNMT complex (RNMT-RAM) is required for repression of these RNAs and proteins during differentiation. The predominant RNA targets of CMTR1 encode the histones and ribosomal proteins (RPs). CMTR1 up-regulation is required to maintain the expression of histones and RPs during differentiation and to maintain DNA replication, RNA translation and cell proliferation. Thus the co-ordinate regulation of RNMT and CMTR1 is required for different aspects of ES cell differentiation. In this review, we discuss the mechanisms by which RNMT and CMTR1 are independently regulated during ES cell differentiation and explore how this influences the co-ordinated gene regulation required of emerging cell lineages.
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Affiliation(s)
- Shang Liang
- Cancer Research UK Beatson Institute, Glasgow, U.K
- School of Cancer Sciences, University of Glasgow, Glasgow G61 1BD, U.K
| | - Rajaei Almohammed
- Cancer Research UK Beatson Institute, Glasgow, U.K
- School of Cancer Sciences, University of Glasgow, Glasgow G61 1BD, U.K
| | - Victoria H Cowling
- Cancer Research UK Beatson Institute, Glasgow, U.K
- School of Cancer Sciences, University of Glasgow, Glasgow G61 1BD, U.K
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10
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Decombe A, El Kazzi P, Decroly E. Interplay of RNA 2'-O-methylations with viral replication. Curr Opin Virol 2023; 59:101302. [PMID: 36764118 DOI: 10.1016/j.coviro.2023.101302] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2022] [Revised: 12/06/2022] [Accepted: 12/19/2022] [Indexed: 02/11/2023]
Abstract
Viral RNAs (vRNAs) are decorated by post-transcriptional modifications, including methylation of nucleotides. Methylations regulate biological functions linked to the sequence, structure, and protein interactome of RNA. Several RNA viruses were found to harbor 2'-O-methylations, affecting the ribose moiety of RNA. This mark was initially shown to target the first and second nucleotides of the 5'-end cap structure of mRNA. More recently, nucleotides within vRNA were also reported to carry 2'-O-methylations. The consequences of such methylations are still puzzling since they were associated with both proviral and antiviral effects. Here, we focus on the mechanisms governing vRNA 2'-O-methylation and we explore the possible roles of this epitranscriptomic modification for viral replication.
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Affiliation(s)
- Alice Decombe
- AFMB, CNRS, Aix-Marseille University, UMR 7257, Case 925, 163 Avenue de Luminy, 13288 Marseille Cedex 09, France
| | - Priscila El Kazzi
- AFMB, CNRS, Aix-Marseille University, UMR 7257, Case 925, 163 Avenue de Luminy, 13288 Marseille Cedex 09, France
| | - Etienne Decroly
- AFMB, CNRS, Aix-Marseille University, UMR 7257, Case 925, 163 Avenue de Luminy, 13288 Marseille Cedex 09, France.
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11
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mRNA-From COVID-19 Treatment to Cancer Immunotherapy. Biomedicines 2023; 11:biomedicines11020308. [PMID: 36830845 PMCID: PMC9953480 DOI: 10.3390/biomedicines11020308] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2022] [Revised: 01/05/2023] [Accepted: 01/09/2023] [Indexed: 01/24/2023] Open
Abstract
This review provides an overview covering mRNA from its use in the COVID-19 pandemic to cancer immunotherapy, starting from the selection of appropriate antigens, tumor-associated and tumor-specific antigens, neoantigens, the basics of optimizing the mRNA molecule in terms of stability, efficacy, and tolerability, choosing the best formulation and the optimal route of administration, to summarizing current clinical trials of mRNA vaccines in tumor therapy.
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12
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Zhang W, Zhang S, Wang Z. Prognostic value of 12 m7G methylation-related miRNA markers and their correlation with immune infiltration in breast cancer. Front Oncol 2022; 12:929363. [PMID: 35992830 PMCID: PMC9389359 DOI: 10.3389/fonc.2022.929363] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Accepted: 07/12/2022] [Indexed: 01/20/2023] Open
Abstract
RNA guanine-7 methyltransferase (RNMT), in complex with FAM103A1, plays an important role in tumorigenesis and development. The aim of this study was to establish a prognostic model of RNMT and FAM103A1-based upstream microRNAs and explore its correlation with immune cell infiltration in breast cancer (BC) while investigating its potential prognostic value and verify the model by quantitative real-time polymerase chain reaction (qRT-PCR). The miRNA expression data upstream of the m7G methyltransferase complex RNMT/FAM103A1 in BC was obtained from The Cancer Genome Atlas and TargetScan databases. We performed univariate Cox regression, LASSO regression, Kaplan-Meier survival, and principal component analyses, along with risk prognostic modelling. Based on multivariate Cox regression analysis, a total of 12 m7G methyltransferase-related miRNAs were found. The model showed good accuracy for predicting the 1-, 3-,5-, and 10-year survival rates, and the areas under the curve were almost >0.7. To characterize the risk-level model constructed from 12 miRNAs, 12 differentially expressed mRNAs related to prognosis and immune infiltration were obtained. The prognosis of BC patients is well predicted by the risk model we constructed. This model is also closely related to immune infiltration, and new immunotherapy targets can be explored from this field.
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13
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Kurgina TA, Shram SI, Kutuzov MM, Abramova TV, Shcherbakova TA, Maltseva EA, Poroikov VV, Lavrik OI, Švedas VK, Nilov DK. Inhibitory Effects of 7-Methylguanine and Its Metabolite 8-Hydroxy-7-Methylguanine on Human Poly(ADP-Ribose) Polymerase 1. BIOCHEMISTRY. BIOKHIMIIA 2022; 87:823-831. [PMID: 36171646 DOI: 10.1134/s0006297922080132] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/22/2022] [Revised: 05/23/2022] [Accepted: 05/23/2022] [Indexed: 06/16/2023]
Abstract
Previously, we have found that a nucleic acid metabolite, 7-methylguanine (7mGua), produced in the body can have an inhibitory effect on the poly(ADP-ribose) polymerase 1 (PARP1) enzyme, an important pharmacological target in anticancer therapy. In this work, using an original method of analysis of PARP1 activity based on monitoring fluorescence anisotropy, we studied inhibitory properties of 7mGua and its metabolite, 8-hydroxy-7-methylguanine (8h7mGua). Both compounds inhibited PARP1 enzymatic activity in a dose-dependent manner, however, 8h7mGua was shown to be a stronger inhibitor. The IC50 values for 8h7mGua at different concentrations of the NAD+ substrate were found to be 4 times lower, on average, than those for 7mGua. The more efficient binding of 8h7mGua in the PARP1 active site is explained by the presence of an additional hydrogen bond with the Glu988 catalytic residue. Experimental and computational studies did not reveal the effect of 7mGua and 8h7mGua on the activity of other DNA repair enzymes, indicating selectivity of their inhibitory action.
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Affiliation(s)
- Tatyana A Kurgina
- Institute of Chemical Biology and Fundamental Medicine, Russian Academy of Sciences, Siberian Branch, Novosibirsk, 630090, Russia
| | - Stanislav I Shram
- Institute of Molecular Genetics of National Research Center "Kurchatov Institute", Moscow, 123182, Russia
| | - Mikhail M Kutuzov
- Institute of Chemical Biology and Fundamental Medicine, Russian Academy of Sciences, Siberian Branch, Novosibirsk, 630090, Russia
| | - Tatyana V Abramova
- Institute of Chemical Biology and Fundamental Medicine, Russian Academy of Sciences, Siberian Branch, Novosibirsk, 630090, Russia
| | - Tatyana A Shcherbakova
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119991, Russia
| | - Ekaterina A Maltseva
- Institute of Chemical Biology and Fundamental Medicine, Russian Academy of Sciences, Siberian Branch, Novosibirsk, 630090, Russia
| | | | - Olga I Lavrik
- Institute of Chemical Biology and Fundamental Medicine, Russian Academy of Sciences, Siberian Branch, Novosibirsk, 630090, Russia
- Novosibirsk State University, Novosibirsk, 630090, Russia
| | - Vytas K Švedas
- Faculty of Bioengineering and Bioinformatics, Lomonosov Moscow State University, Moscow, 119991, Russia
- Research Computing Center, Lomonosov Moscow State University, Moscow, 119991, Russia
| | - Dmitry K Nilov
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119991, Russia.
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14
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Kirsanov K, Fetisov T, Antoshina E, Trukhanova L, Gor'kova T, Vlasova O, Khitrovo I, Lesovaya E, Kulbachevskaya N, Shcherbakova T, Belitsky G, Yakubovskaya M, Švedas V, Nilov D. Toxicological Properties of 7-Methylguanine, and Preliminary Data on its Anticancer Activity. Front Pharmacol 2022; 13:842316. [PMID: 35873588 PMCID: PMC9299380 DOI: 10.3389/fphar.2022.842316] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Accepted: 06/13/2022] [Indexed: 11/13/2022] Open
Abstract
7-Methylguanine (7-MG) competitively inhibits the DNA repair enzyme poly(ADP-ribose) polymerase (PARP) and RNA-modifying enzyme tRNA-guanine transglycosylase (TGT) and represents a potential anticancer drug candidate. Furthermore, as a natural compound, it could escape the serious side effects characteristic for approved synthetic PARP inhibitors. Here we present a comprehensive study of toxicological and carcinogenic properties of 7-MG. It was demonstrated that 7-MG does not induce mutations or structural chromosomal abnormalities, and has no blastomogenic activity. A treatment regimen with 7-MG has been established in mice (50 mg/kg per os, 3 times per week), exerting no adverse effects or changes in morphology. Preliminary data on the 7-MG anticancer activity obtained on transplantable tumor models support our conclusions that 7-MG can become a promising new component of chemotherapy.
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Affiliation(s)
- Kirill Kirsanov
- Blokhin Cancer Research Center, Moscow, Russia.,Peoples' Friendship University of Russia, Moscow, Russia
| | | | | | | | | | | | | | - Ekaterina Lesovaya
- Blokhin Cancer Research Center, Moscow, Russia.,Pavlov Ryazan State Medical University, Ryazan, Russia
| | | | - Tatiana Shcherbakova
- Belozersky Institute of Physicochemical Biology, Lomonosov Moscow State University, Moscow, Russia
| | | | | | - Vytas Švedas
- Belozersky Institute of Physicochemical Biology, Lomonosov Moscow State University, Moscow, Russia.,Faculty of Bioengineering and Bioinformatics, Lomonosov Moscow State University, Moscow, Russia
| | - Dmitry Nilov
- Belozersky Institute of Physicochemical Biology, Lomonosov Moscow State University, Moscow, Russia
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15
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Sáez Moreno D, Udi Q, Azeredo J, Domingues L. Towards T7 RNA polymerase (T7RNAP)-based expression system in yeast: challenges and opportunities. Bioengineered 2022; 13:14947-14959. [PMID: 37105766 DOI: 10.1080/21655979.2023.2180579] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/29/2023] Open
Abstract
During the last decades, we have witnessed unprecedented advances in biological engineering and synthetic biology. These disciplines aim to take advantage of gene pathway regulation and gene expression in different organisms, to enable cells to perform desired functions. Yeast has been widely utilized as a model for the study of eukaryotic protein expression while bacteriophage T7RNAP and its promoter constitute the preferred system for prokaryotic protein expression (such as pET-based expression systems). The ability to integrate a T7RNAP-based expression system in yeast could allow for a better understanding of gene regulation in eukaryotic cells, and potentially increase the efficiency and processivity of yeast as an expression system. However, the attempts for the creation of such a system have been unsuccessful to date. This review aims to: (i) summarize the efforts that, for many years, have been devoted to the creation of a T7RNAP-based yeast expression system and ii) provide an overview of the latest advances in knowledge of eukaryotic transcription and translation that could lead to the construction of a successful T7RNAP expression system in yeast. The completion of this new expression system would allow to further expand the toolkit of yeast in synthetic biology and ultimately contribute to boost yeast usage as a key cell factory in sustainable biorefinery and circular economy.
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Affiliation(s)
- David Sáez Moreno
- CEB-Centre of Biological Engineering, University of Minho, 4710-057, Braga, Portugal
- LABBELS-Associate Laboratory, 4835-198, Guimarães, Braga, Portugal
| | - Qimron Udi
- Department of Clinical Microbiology and Immunology, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Joana Azeredo
- CEB-Centre of Biological Engineering, University of Minho, 4710-057, Braga, Portugal
- LABBELS-Associate Laboratory, 4835-198, Guimarães, Braga, Portugal
| | - Lucília Domingues
- CEB-Centre of Biological Engineering, University of Minho, 4710-057, Braga, Portugal
- LABBELS-Associate Laboratory, 4835-198, Guimarães, Braga, Portugal
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16
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Liu J, Fu M, Wang M, Wan D, Wei Y, Wei X. Cancer vaccines as promising immuno-therapeutics: platforms and current progress. J Hematol Oncol 2022; 15:28. [PMID: 35303904 PMCID: PMC8931585 DOI: 10.1186/s13045-022-01247-x] [Citation(s) in RCA: 265] [Impact Index Per Article: 132.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Accepted: 03/03/2022] [Indexed: 02/08/2023] Open
Abstract
Research on tumor immunotherapy has made tremendous progress in the past decades, with numerous studies entering the clinical evaluation. The cancer vaccine is considered a promising therapeutic strategy in the immunotherapy of solid tumors. Cancer vaccine stimulates anti-tumor immunity with tumor antigens, which could be delivered in the form of whole cells, peptides, nucleic acids, etc. Ideal cancer vaccines could overcome the immune suppression in tumors and induce both humoral immunity and cellular immunity. In this review, we introduced the working mechanism of cancer vaccines and summarized four platforms for cancer vaccine development. We also highlighted the clinical research progress of the cancer vaccines, especially focusing on their clinical application and therapeutic efficacy, which might hopefully facilitate the future design of the cancer vaccine.
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Affiliation(s)
- Jian Liu
- Laboratory of Aging Research and Cancer Drug Target, State Key Laboratory of Biotherapy, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, No. 17, Block 3, Southern Renmin Road, Chengdu, 610041, Sichuan, People's Republic of China
| | - Minyang Fu
- Laboratory of Aging Research and Cancer Drug Target, State Key Laboratory of Biotherapy, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, No. 17, Block 3, Southern Renmin Road, Chengdu, 610041, Sichuan, People's Republic of China
| | - Manni Wang
- Laboratory of Aging Research and Cancer Drug Target, State Key Laboratory of Biotherapy, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, No. 17, Block 3, Southern Renmin Road, Chengdu, 610041, Sichuan, People's Republic of China
| | - Dandan Wan
- Laboratory of Aging Research and Cancer Drug Target, State Key Laboratory of Biotherapy, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, No. 17, Block 3, Southern Renmin Road, Chengdu, 610041, Sichuan, People's Republic of China
| | - Yuquan Wei
- Laboratory of Aging Research and Cancer Drug Target, State Key Laboratory of Biotherapy, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, No. 17, Block 3, Southern Renmin Road, Chengdu, 610041, Sichuan, People's Republic of China
| | - Xiawei Wei
- Laboratory of Aging Research and Cancer Drug Target, State Key Laboratory of Biotherapy, National Clinical Research Center for Geriatrics, West China Hospital, Sichuan University, No. 17, Block 3, Southern Renmin Road, Chengdu, 610041, Sichuan, People's Republic of China.
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17
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Bhargavi S, Madhan Shankar SR, Jemmy CH. In silico and in vitro studies on inhibitors for SARS-CoV-2 non-structural proteins with dual herbal combination of Withania somnifera with five rasayana herbs. J Biomol Struct Dyn 2022; 41:3265-3280. [PMID: 35257637 DOI: 10.1080/07391102.2022.2046642] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Being highly transmissible, severe acute respiratory syndrome coronavirus (SARS-CoV-2) has affected millions of people causing devastating global impact and has also not slowed down even after vaccination. The emerges of new strains has made more concerns than the original one. We need a new therapeutic approach against the disease. Our comprehensive in silico study investigates dual herbal combinatorial methanolic extracts of W. somnifera (W) alone and with P. emblica (P) (W:P/1:4) , T. sinensis (T) (W:T/1:4), B. monnieri (B) (W:B/1:1), O. basilicum (O) (W:O/1:4), A. racemosus (A) (W:A/4:1) for potential four phytochemicals as ligands docked with eight COVID-19 Nonstructural proteins (nsp)-main protease (PDB ID:6LU7), papain-like protease (6WUU), helicase ADP (2XZL), N7-methyltransferase (5C8S), endoribonuclease (6WLC), 2'O-methyltransferase (6WVN), RNA dependent RNA polymerase (6M71), and 3Cprotease (6YNQ) along with Remdesivir and Hydroxychloroquine. Ligands from W:P/1:4 showed remarkable docking score (-9.01 kcal/mol) 6M71-(8E,11E,14E)-eicosa-8,11,14-trienoicacidmethylester (EIS) and (-9.99 kcal/mol) 6YNQ-N-[(E)-[4-[(2-methoxydibenzofuran-3-yl)amino]-4-oxobutan-2-ylidene]amino] 4nitrobenzamide (MET). Further, MD simulations were studied for 100 ns and showed the complexes were flexible, stable in the binding pockets of the receptors, and MM-PBSA analysis determined high binding energy of -129.673 ± 15.284 and -134.594 ± 7.085 for 6M71-EIS (Asn496, Lys577, Arg569) and 6YNQ-MET (Cys145, His41). Finally, in vitro JURKAT E6.1 cell lines treated with W:P/1:4 and W:O/1:4 methanolic extracts yielded 44.06 and 31.53 ng/mL levels for interferon alpha to counteract an external stimulus by establishing an antiviral state. Thus, nsp is targeted to design effective antiviral drugs for developing an effective therapeutic approach to combat viral RNA synthesis, processing, and suppression of host immunity.Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Srinivasan Bhargavi
- Department of Biotechnology, Kongunadu Arts and Science college, Coimbatore, Tamilnadu, India
| | - S. R. Madhan Shankar
- Department of Biotechnology, Kongunadu Arts and Science college, Coimbatore, Tamilnadu, India
| | - Christy H. Jemmy
- Department of Bioinformatics, Sathyabama Institute of Science and Technology, Chennai, Tamilnadu, India
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18
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Kasprzyk R, Jemielity J. Enzymatic Assays to Explore Viral mRNA Capping Machinery. Chembiochem 2021; 22:3236-3253. [PMID: 34291555 PMCID: PMC8426721 DOI: 10.1002/cbic.202100291] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Revised: 07/21/2021] [Indexed: 12/25/2022]
Abstract
In eukaryotes, mRNA is modified by the addition of the 7-methylguanosine (m7 G) 5' cap to protect mRNA from premature degradation, thereby enhancing translation and enabling differentiation between self (endogenous) and non-self RNAs (e. g., viral ones). Viruses often develop their own mRNA capping pathways to augment the expression of their proteins and escape host innate immune response. Insights into this capping system may provide new ideas for therapeutic interventions and facilitate drug discovery, e. g., against viruses that cause pandemic outbreaks, such as beta-coronaviruses SARS-CoV (2002), MARS-CoV (2012), and the most recent SARS-CoV-2. Thus, proper methods for the screening of large compound libraries are required to identify lead structures that could serve as a basis for rational antiviral drug design. This review summarizes the methods that allow the monitoring of the activity and inhibition of enzymes involved in mRNA capping.
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Affiliation(s)
- Renata Kasprzyk
- Centre of New TechnologiesUniversity of WarsawBanacha 2c02-097WarsawPoland
- College of Inter-Faculty Individual Studies inMathematics and Natural SciencesUniversity of WarsawBanacha 2c02-097WarsawPoland
| | - Jacek Jemielity
- Centre of New TechnologiesUniversity of WarsawBanacha 2c02-097WarsawPoland
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19
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Pace L. Temporal and Epigenetic Control of Plasticity and Fate Decision during CD8 + T-Cell Memory Differentiation. Cold Spring Harb Perspect Biol 2021; 13:a037754. [PMID: 33972365 PMCID: PMC8635004 DOI: 10.1101/cshperspect.a037754] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Immunological memory is a fundamental hallmark of the adaptive immune responses and one of the most relevant aspects of protective immunity. Our understanding of the processes of memory T-cell differentiation and maintenance of long-term immunity is continuously evolving, and recent advances highlight new regulatory networks and chromatin dynamic changes contributing to maintain T-cell identity and impeding the reprogramming of specific T-cell states. Here, the current understanding of the mechanisms that generate the diversity and the heterogeneity of CD8+ T-cell subsets will be discussed, focusing on the temporal and epigenetic mechanisms orchestrating the establishment and maintenance of distinct states of T-cell fate determination and functional commitment.
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Affiliation(s)
- Luigia Pace
- Armenise-Harvard Immune Regulation Unit, IIGM
- Candiolo Cancer Institute, FPO-IRCCS, Candiolo (TO) 10060, Italy
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20
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Wood S, Willbanks A, Cheng JX. The Role of RNA Modifications and RNA-modifying Proteins in Cancer Therapy and Drug Resistance. Curr Cancer Drug Targets 2021; 21:326-352. [PMID: 33504307 DOI: 10.2174/1568009621666210127092828] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Revised: 12/03/2020] [Accepted: 12/03/2020] [Indexed: 11/22/2022]
Abstract
The advent of new genome-wide sequencing technologies has uncovered abnormal RNA modifications and RNA editing in a variety of human cancers. The discovery of reversible RNA N6-methyladenosine (RNA: m6A) by fat mass and obesity-associated protein (FTO) demethylase has led to exponential publications on the pathophysiological functions of m6A and its corresponding RNA modifying proteins (RMPs) in the past decade. Some excellent reviews have summarized the recent progress in this field. Compared to the extent of research into RNA: m6A and DNA 5-methylcytosine (DNA: m5C), much less is known about other RNA modifications and their associated RMPs, such as the role of RNA: m5C and its RNA cytosine methyltransferases (RCMTs) in cancer therapy and drug resistance. In this review, we will summarize the recent progress surrounding the function, intramolecular distribution and subcellular localization of several major RNA modifications, including 5' cap N7-methylguanosine (m7G) and 2'-O-methylation (Nm), m6A, m5C, A-to-I editing, and the associated RMPs. We will then discuss dysregulation of those RNA modifications and RMPs in cancer and their role in cancer therapy and drug resistance.
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Affiliation(s)
- Shaun Wood
- Department of Pathology, Hematopathology Section, University of Chicago, Chicago, IL60637, United States
| | - Amber Willbanks
- Department of Pathology, Hematopathology Section, University of Chicago, Chicago, IL60637, United States
| | - Jason X Cheng
- Department of Pathology, Hematopathology Section, University of Chicago, Chicago, IL60637, United States
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21
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Graille M. Division of labor in epitranscriptomics: What have we learnt from the structures of eukaryotic and viral multimeric RNA methyltransferases? WILEY INTERDISCIPLINARY REVIEWS-RNA 2021; 13:e1673. [PMID: 34044474 DOI: 10.1002/wrna.1673] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Revised: 04/30/2021] [Accepted: 05/04/2021] [Indexed: 02/06/2023]
Abstract
The translation of an mRNA template into the corresponding protein is a highly complex and regulated choreography performed by ribosomes, tRNAs, and translation factors. Most RNAs involved in this process are decorated by multiple chemical modifications (known as epitranscriptomic marks) contributing to the efficiency, the fidelity, and the regulation of the mRNA translation process. Many of these epitranscriptomic marks are written by holoenzymes made of a catalytic subunit associated with an activating subunit. These holoenzymes play critical roles in cell development. Indeed, several mutations being identified in the genes encoding for those proteins are linked to human pathologies such as cancers and intellectual disorders for instance. This review describes the structural and functional properties of RNA methyltransferase holoenzymes, which when mutated often result in brain development pathologies. It illustrates how structurally different activating subunits contribute to the catalytic activity of these holoenzymes through common mechanistic trends that most likely apply to other classes of holoenzymes. This article is categorized under: RNA Processing > RNA Editing and Modification RNA Processing > Capping and 5' End Modifications.
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Affiliation(s)
- Marc Graille
- Laboratoire de Biologie Structurale de la Cellule (BIOC), CNRS, Ecole Polytechnique, IP Paris, Palaiseau Cedex, France
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22
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Interplay of mRNA capping and transcription machineries. Biosci Rep 2021; 40:221784. [PMID: 31904821 PMCID: PMC6981093 DOI: 10.1042/bsr20192825] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Revised: 01/02/2020] [Accepted: 01/06/2020] [Indexed: 12/31/2022] Open
Abstract
Early stages of transcription from eukaryotic promoters include two principal events: the capping of newly synthesized mRNA and the transition of RNA polymerase II from the preinitiation complex to the productive elongation state. The capping checkpoint model implies that these events are tightly coupled, which is necessary for ensuring the proper capping of newly synthesized mRNA. Recent findings also show that the capping machinery has a wider effect on transcription and the entire gene expression process. The molecular basis of these phenomena is discussed.
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23
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Structure and Biochemical Characteristic of the Methyltransferase (MTase) Domain of RNA Capping Enzyme from African Swine Fever Virus. J Virol 2021; 95:JVI.02029-20. [PMID: 33268516 PMCID: PMC8092831 DOI: 10.1128/jvi.02029-20] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
African swine fever virus (ASFV) is a complex nucleocytoplasmic large DNA virus (NCLDV) that causes a devastating swine disease and it is urgently needed to develop effective anti-ASFV vaccines and drugs. The process of mRNA 5'-end capping is a common characteristic in eukaryotes and many viruses, and the cap structure is required for mRNA stability and efficient translation. The ASFV protein pNP868R was found to have guanylyltransferase (GTase) activity involved in mRNA capping. Here we report the crystal structure of pNP868R methyltransferase (MTase) domain (referred as pNP868RMT) in complex with S-adenosyl-L-methionine (AdoMet). The structure shows the characteristic core fold of the class I MTase family and the AdoMet is bound in a negative-deep groove. Remarkably, the N-terminal extension of pNP868RMT is ordered and keeps away from the AdoMet-binding site, distinct from the close conformation over the active site of poxvirus RNA capping D1 subunit or the largely disordered conformation in most cellular RNA capping MTases. Structure-based mutagenesis studies based on the pNP868RMT-cap analog complex model revealed essential residues involved in substrate recognition and binding. Functional studies suggest the N-terminal extension may play an essential role in substrate recognition instead of AdoMet-binding. A positively charged path stretching from the N-terminal extension to the region around the active site was suggested to provide a favorable electrostatic environment for the binding and approaching of substrate RNA into the active site. Our structure and biochemical studies provide novel insights into the methyltransfer process of mRNA cap catalyzed by pNP868R.IMPORTANCE African swine fever (ASF) is a highly contagious hemorrhagic viral disease in pigs that is caused by African swine fever virus (ASFV). There are no effective drugs or vaccines for protection against ASFV infection till now. The protein pNP868R was predicted to be responsible for process of mRNA 5'-end capping in ASFV, which is essential for mRNA stability and efficient translation. Here, we solved the high-resolution crystal structure of the methyltransferase (MTase) domain of pNP868R. The MTase domain structure shows a canonical class I MTase family fold and the AdoMet binds into a negative pocket. Structure-based mutagenesis studies revealed critical and conserved residues involved in AdoMet-binding and substrate RNA-binding. Notably, both the conformation and the role in MTase activities of the N-terminal extension are distinct from those of previously characterized poxvirus MTase domain. Our structure-function studies provide the basis for potential anti-ASFV inhibitor design targeting the critical enzyme.
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24
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CMTR1-Catalyzed 2'-O-Ribose Methylation Controls Neuronal Development by Regulating Camk2α Expression Independent of RIG-I Signaling. Cell Rep 2020; 33:108269. [PMID: 33086056 PMCID: PMC7574844 DOI: 10.1016/j.celrep.2020.108269] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Revised: 08/10/2020] [Accepted: 09/23/2020] [Indexed: 12/14/2022] Open
Abstract
Eukaryotic mRNAs are 5′ end capped with a 7-methylguanosine, which is important for processing and translation of mRNAs. Cap methyltransferase 1 (CMTR1) catalyzes 2′-O-ribose methylation of the first transcribed nucleotide (N1 2′-O-Me) to mask mRNAs from innate immune surveillance by retinoic-acid-inducible gene-I (RIG-I). Nevertheless, whether this modification regulates gene expression for neuronal functions remains unexplored. Here, we find that knockdown of CMTR1 impairs dendrite development independent of secretory cytokines and RIG-I signaling. Using transcriptomic analyses, we identify altered gene expression related to dendrite morphogenesis instead of RIG-I-activated interferon signaling, such as decreased calcium/calmodulin-dependent protein kinase 2α (Camk2α). In line with these molecular changes, dendritic complexity in CMTR1-insufficient neurons is rescued by ectopic expression of CaMK2α but not by inactivation of RIG-I signaling. We further generate brain-specific CMTR1-knockout mice to validate these findings in vivo. Our study reveals the indispensable role of CMTR1-catalyzed N1 2′-O-Me in gene regulation for brain development. Every mRNA molecule in neurons is N1 2′-O methylated by CMTR1 CMTR1 is essential for neuromorphogenesis and brain development CMTR1 deficiency does not activate RIG-I and interferon signaling CMTR1 promotes Camk2α expression to support dendrite development
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25
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Slobodin B, Dikstein R. So close, no matter how far: multiple paths connecting transcription to mRNA translation in eukaryotes. EMBO Rep 2020; 21:e50799. [PMID: 32803873 PMCID: PMC7507372 DOI: 10.15252/embr.202050799] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Revised: 06/22/2020] [Accepted: 07/23/2020] [Indexed: 12/15/2022] Open
Abstract
Transcription of DNA into mRNA and translation of mRNA into proteins are two major processes underlying gene expression. Due to the distinct molecular mechanisms, timings, and locales of action, these processes are mainly considered to be independent. During the last two decades, however, multiple factors and elements were shown to coordinate transcription and translation, suggesting an intricate level of synchronization. This review discusses the molecular mechanisms that impact both processes in eukaryotic cells of different origins. The emerging global picture suggests evolutionarily conserved regulation and coordination between transcription and mRNA translation, indicating the importance of this phenomenon for the fine-tuning of gene expression and the adjustment to constantly changing conditions.
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Affiliation(s)
- Boris Slobodin
- Department of Biomolecular SciencesThe Weizmann Institute of ScienceRehovotIsrael
| | - Rivka Dikstein
- Department of Biomolecular SciencesThe Weizmann Institute of ScienceRehovotIsrael
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26
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Kasprzyk R, Fido M, Mamot A, Wanat P, Smietanski M, Kopcial M, Cowling VH, Kowalska J, Jemielity J. Direct High-Throughput Screening Assay for mRNA Cap Guanine-N7 Methyltransferase Activity. Chemistry 2020; 26:11266-11275. [PMID: 32259329 PMCID: PMC7262028 DOI: 10.1002/chem.202001036] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Revised: 04/01/2020] [Indexed: 12/16/2022]
Abstract
In eukaryotes, mature mRNA is formed through modifications of precursor mRNA, one of which is 5' cap biosynthesis, involving RNA cap guanine-N7 methyltransferase (N7-MTase). N7-MTases are also encoded by some eukaryotic viruses and facilitate their replication. N7-MTase inhibitors have therapeutic potential, but their discovery is difficult because long RNA substrates are usually required for activity. Herein, we report a universal N7-MTase activity assay based on small-molecule fluorescent probes. We synthesized 12 fluorescent substrate analogues (GpppA and GpppG derivatives) varying in the dye type, dye attachment site, and linker length. GpppA labeled with pyrene at the 3'-O position of adenosine acted as an artificial substrate with the properties of a turn-off probe for all three tested N7-MTases (human, parasite, and viral). Using this compound, a N7-MTase inhibitor assay adaptable to high-throughput screening was developed and used to screen synthetic substrate analogues and a commercial library. Several inhibitors with nanomolar activities were identified.
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Affiliation(s)
- Renata Kasprzyk
- Centre of New TechnologiesUniversity of WarsawBanacha 2c02097WarsawPoland
- College of Inter-Faculty Individual Studies in Mathematics and Natural SciencesUniversity of WarsawBanacha 2c02097WarsawPoland
| | - Mateusz Fido
- Division of BiophysicsInstitute of Experimental PhysicsFaculty of PhysicsUniversity of WarsawPasteura 502093WarsawPoland
| | - Adam Mamot
- Division of BiophysicsInstitute of Experimental PhysicsFaculty of PhysicsUniversity of WarsawPasteura 502093WarsawPoland
| | - Przemyslaw Wanat
- Division of BiophysicsInstitute of Experimental PhysicsFaculty of PhysicsUniversity of WarsawPasteura 502093WarsawPoland
| | | | - Michal Kopcial
- Centre of New TechnologiesUniversity of WarsawBanacha 2c02097WarsawPoland
- College of Inter-Faculty Individual Studies in Mathematics and Natural SciencesUniversity of WarsawBanacha 2c02097WarsawPoland
| | - Victoria H. Cowling
- Centre of Gene Regulation and ExpressionSchool of Life SciencesUniversity of DundeeDD1 5EHDundeeUK
| | - Joanna Kowalska
- Division of BiophysicsInstitute of Experimental PhysicsFaculty of PhysicsUniversity of WarsawPasteura 502093WarsawPoland
| | - Jacek Jemielity
- Centre of New TechnologiesUniversity of WarsawBanacha 2c02097WarsawPoland
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27
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Shao X, Zhang H, Yang Z, Zhong H, Xia Y, Cai Z. NAD tagSeq for transcriptome-wide identification and characterization of NAD +-capped RNAs. Nat Protoc 2020; 15:2813-2836. [PMID: 32747820 DOI: 10.1038/s41596-020-0363-z] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2019] [Accepted: 04/29/2020] [Indexed: 11/09/2022]
Abstract
Several noncanonical initial nucleotides (NCINs) have been found to cap RNAs and possibly regulate RNA stability, transcription and translation. NAD+ is one of the NCINs that has recently been discovered to cap RNAs in a wide range of species. Identification of the NAD+-capped RNAs (NAD-RNAs) could help to unveil the cap-mediated regulation mechanisms. We previously reported a method termed NAD tagSeq for genome-wide analysis of NAD-RNAs. NAD tagSeq is based on the previously published NAD captureSeq protocol, which applies an enzymatic reaction and a click chemistry reaction to label NAD-RNAs with biotin followed by enrichment with streptavidin resin and identification by RNA sequencing. In the current NAD tagSeq method, NAD-RNAs are labeled with a synthetic RNA tag and identified by direct RNA sequencing based on Oxford Nanopore technology. Compared to NAD captureSeq, NAD tagSeq provides a simpler procedure for direct sequencing of NAD-RNAs and noncapped RNAs and affords information on the whole sequence organization of NAD-RNAs and the ratio of NAD-RNAs to total transcripts. Furthermore, NAD-RNAs can be enriched by hybridizing a complementary DNA probe to the RNA tag, thus increasing the sequencing coverage of NAD-RNAs. The strategy of tagging RNAs with a synthetic RNA tag and identifying them by direct RNA sequencing might be employed in analyzing other NCIN-capped RNAs. The experimental procedure of NAD tagSeq, including RNA extraction, RNA tagging and direct RNA sequencing, takes ~5 d, and initial data analysis can be completed within 2 d.
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Affiliation(s)
- Xiaojian Shao
- State Key Laboratory of Environmental and Biological Analysis, Department of Chemistry, Hong Kong Baptist University, Hong Kong, China
| | - Hailei Zhang
- Department of Biology, Hong Kong Baptist University, Hong Kong, China
| | - Zhu Yang
- State Key Laboratory of Environmental and Biological Analysis, Department of Chemistry, Hong Kong Baptist University, Hong Kong, China
| | - Huan Zhong
- Department of Biology, Hong Kong Baptist University, Hong Kong, China
| | - Yiji Xia
- State Key Laboratory of Environmental and Biological Analysis, Department of Chemistry, Hong Kong Baptist University, Hong Kong, China. .,Department of Biology, Hong Kong Baptist University, Hong Kong, China. .,State Key Laboratory of Agrobiotechnology, The Chinese University of Hong Kong, Hong Kong, China.
| | - Zongwei Cai
- State Key Laboratory of Environmental and Biological Analysis, Department of Chemistry, Hong Kong Baptist University, Hong Kong, China.
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28
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Takagi Y, Kuwabara N, Dang TT, Furukawa K, Ho CK. Crystal structures of the RNA triphosphatase from Trypanosoma cruzi provide insights into how it recognizes the 5'-end of the RNA substrate. J Biol Chem 2020; 295:9076-9086. [PMID: 32381506 PMCID: PMC7335777 DOI: 10.1074/jbc.ra119.011811] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Revised: 05/06/2020] [Indexed: 11/06/2022] Open
Abstract
RNA triphosphatase catalyzes the first step in mRNA cap formation, hydrolysis of the terminal phosphate from the nascent mRNA transcript. The RNA triphosphatase from the protozoan parasite Trypanosoma cruzi, TcCet1, belongs to the family of triphosphate tunnel metalloenzymes (TTMs). TcCet1 is a promising antiprotozoal drug target because the mechanism and structure of the protozoan RNA triphosphatases are completely different from those of the RNA triphosphatases found in mammalian and arthropod hosts. Here, we report several crystal structures of the catalytically active form of TcCet1 complexed with a divalent cation and an inorganic tripolyphosphate in the active-site tunnel at 2.20-2.51 Å resolutions. The structures revealed that the overall structure, the architecture of the tunnel, and the arrangement of the metal-binding site in TcCet1 are similar to those in other TTM proteins. On the basis of the position of three sulfate ions that cocrystallized on the positively charged surface of the protein and results obtained from mutational analysis, we identified an RNA-binding site in TcCet1. We conclude that the 5'-end of the triphosphate RNA substrate enters the active-site tunnel directionally. The structural information reported here provides valuable insight into designing inhibitors that could specifically block the entry of the triphosphate RNA substrate into the TTM-type RNA triphosphatases of T. cruzi and related pathogens.
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Affiliation(s)
- Yuko Takagi
- Biomedical Research Institute, National Institute of Advanced Industrial Science and Technology, Tsukuba, Ibaraki, Japan
| | - Naoyuki Kuwabara
- Structural Biology Research Center, Institute of Materials Structure Science, High Energy Accelerator Research Organization, Tsukuba, Ibaraki, Japan
| | - Truong Tat Dang
- Faculty of Medicine, University of Tsukuba, Tsukuba, Ibaraki Japan
| | - Koji Furukawa
- Biomedical Research Institute, National Institute of Advanced Industrial Science and Technology, Tsukuba, Ibaraki, Japan
| | - C Kiong Ho
- Faculty of Medicine, University of Tsukuba, Tsukuba, Ibaraki Japan.
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29
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The C-Terminal Domain of the Sudan Ebolavirus L Protein Is Essential for RNA Binding and Methylation. J Virol 2020; 94:JVI.00520-20. [PMID: 32269120 DOI: 10.1128/jvi.00520-20] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2020] [Accepted: 03/29/2020] [Indexed: 12/20/2022] Open
Abstract
The large (L) protein of Ebola virus is a key protein for virus replication. Its N-terminal region harbors the RNA-dependent RNA polymerase activity, and its C terminus contains a cap assembling line composed of a capping domain and a methyltransferase domain (MTase) followed by a C-terminal domain (CTD) of unknown function. The L protein MTase catalyzes methylation at the 2'-O and N-7 positions of the cap structures. In addition, the MTase of Ebola virus can induce cap-independent internal adenosine 2'-O-methylation. In this work, we investigated the CTD role in the regulation of the cap-dependent and cap-independent MTase activities of the L protein. We found that the CTD, which is enriched in basic amino acids, plays a key role in RNA binding and in turn regulates the different MTase activities. We demonstrated that the mutation of CTD residues modulates specifically the different MTase activities. Altogether, our results highlight the pivotal role of the L protein CTD in the control of viral RNA methylation, which is critical for Ebola virus replication and escape from the innate response in infected cells.IMPORTANCE Ebola virus infects human and nonhuman primates, causing severe infections that are often fatal. The epidemics, in West and Central Africa, emphasize the urgent need to develop antiviral therapies. The Ebola virus large protein (L), which is the central protein for viral RNA replication/transcription, harbors a methyltransferase domain followed by a C-terminal domain of unknown function. We show that the C-terminal domain regulates the L protein methyltransferase activities and consequently participates in viral replication and escape of the host innate immunity.
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30
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Lu M, Zhang Z, Xue M, Zhao BS, Harder O, Li A, Liang X, Gao TZ, Xu Y, Zhou J, Feng Z, Niewiesk S, Peeples ME, He C, Li J. N 6-methyladenosine modification enables viral RNA to escape recognition by RNA sensor RIG-I. Nat Microbiol 2020; 5:584-598. [PMID: 32015498 PMCID: PMC7137398 DOI: 10.1038/s41564-019-0653-9] [Citation(s) in RCA: 158] [Impact Index Per Article: 39.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Accepted: 12/03/2019] [Indexed: 12/18/2022]
Abstract
Internal N6-methyladenosine (m6A) modification is one of the most common and abundant modifications of RNA. However, the biological roles of viral RNA m6A remain elusive. Here, using human metapneumovirus (HMPV) as a model, we demonstrate that m6A serves as a molecular marker for innate immune discrimination of self from non-self RNAs. We show that HMPV RNAs are m6A methylated and that viral m6A methylation promotes HMPV replication and gene expression. Inactivating m6A addition sites with synonymous mutations or demethylase resulted in m6A-deficient recombinant HMPVs and virion RNAs that induced increased expression of type I interferon, which was dependent on the cytoplasmic RNA sensor RIG-I, and not on melanoma differentiation-associated protein 5 (MDA5). Mechanistically, m6A-deficient virion RNA induces higher expression of RIG-I, binds more efficiently to RIG-I and facilitates the conformational change of RIG-I, leading to enhanced interferon expression. Furthermore, m6A-deficient recombinant HMPVs triggered increased interferon in vivo and were attenuated in cotton rats but retained high immunogenicity. Collectively, our results highlight that (1) viruses acquire m6A in their RNA as a means of mimicking cellular RNA to avoid detection by innate immunity and (2) viral RNA m6A can serve as a target to attenuate HMPV for vaccine purposes.
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Affiliation(s)
- Mijia Lu
- Department of Veterinary Biosciences, College of Veterinary Medicine, The Ohio State University, Columbus, OH, USA
| | - Zijie Zhang
- Department of Chemistry, The University of Chicago, Chicago, IL, USA
| | - Miaoge Xue
- Department of Veterinary Biosciences, College of Veterinary Medicine, The Ohio State University, Columbus, OH, USA
| | - Boxuan Simen Zhao
- Department of Chemistry, The University of Chicago, Chicago, IL, USA
| | - Olivia Harder
- Department of Veterinary Biosciences, College of Veterinary Medicine, The Ohio State University, Columbus, OH, USA
| | - Anzhong Li
- Department of Veterinary Biosciences, College of Veterinary Medicine, The Ohio State University, Columbus, OH, USA
| | - Xueya Liang
- Department of Veterinary Biosciences, College of Veterinary Medicine, The Ohio State University, Columbus, OH, USA
| | - Thomas Z Gao
- Department of Veterinary Biosciences, College of Veterinary Medicine, The Ohio State University, Columbus, OH, USA
| | - Yunsheng Xu
- The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, China
| | - Jiyong Zhou
- College of Animal Sciences, Zhejiang University, Hangzhou, China
| | - Zongdi Feng
- Center for Vaccines and Immunity, Abigail Wexner Research Institute at Nationwide Children's Hospital, Columbus, OH, USA
- Department of Pediatrics, The Ohio State University College of Medicine, Columbus, OH, USA
| | - Stefan Niewiesk
- Department of Veterinary Biosciences, College of Veterinary Medicine, The Ohio State University, Columbus, OH, USA
| | - Mark E Peeples
- Center for Vaccines and Immunity, Abigail Wexner Research Institute at Nationwide Children's Hospital, Columbus, OH, USA
- Department of Pediatrics, The Ohio State University College of Medicine, Columbus, OH, USA
| | - Chuan He
- Department of Chemistry, The University of Chicago, Chicago, IL, USA
- Department of Biochemistry and Molecular Biology, The University of Chicago, Chicago, IL, USA
- Institute for Biophysical Dynamics, The University of Chicago, Chicago, IL, USA
- Howard Hughes Medical Institute, The University of Chicago, Chicago, IL, USA
| | - Jianrong Li
- Department of Veterinary Biosciences, College of Veterinary Medicine, The Ohio State University, Columbus, OH, USA.
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31
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Bueren-Calabuig JA, G Bage M, Cowling VH, Pisliakov AV. Mechanism of allosteric activation of human mRNA cap methyltransferase (RNMT) by RAM: insights from accelerated molecular dynamics simulations. Nucleic Acids Res 2019; 47:8675-8692. [PMID: 31329932 PMCID: PMC7145595 DOI: 10.1093/nar/gkz613] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2019] [Revised: 07/01/2019] [Accepted: 07/08/2019] [Indexed: 02/04/2023] Open
Abstract
The RNA guanine-N7 methyltransferase (RNMT) in complex with RNMT-activating miniprotein (RAM) catalyses the formation of a N7-methylated guanosine cap structure on the 5' end of nascent RNA polymerase II transcripts. The mRNA cap protects the primary transcript from exonucleases and recruits cap-binding complexes that mediate RNA processing, export and translation. By using microsecond standard and accelerated molecular dynamics simulations, we provide for the first time a detailed molecular mechanism of allosteric regulation of RNMT by RAM. We show that RAM selects the RNMT active site conformations that are optimal for binding of substrates (AdoMet and the cap), thus enhancing their affinity. Furthermore, our results strongly suggest the likely scenario in which the cap binding promotes the subsequent AdoMet binding, consistent with the previously suggested cooperative binding model. By employing the network community analyses, we revealed the underlying long-range allosteric networks and paths that are crucial for allosteric regulation by RAM. Our findings complement and explain previous experimental data on RNMT activity. Moreover, this study provides the most complete description of the cap and AdoMet binding poses and interactions within the enzyme's active site. This information is critical for the drug discovery efforts that consider RNMT as a promising anti-cancer target.
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Affiliation(s)
- Juan A Bueren-Calabuig
- Computational Biology, School of Life Sciences, University of Dundee, Dundee, DD1 5EH, UK
| | - Marcus G Bage
- Computational Biology, School of Life Sciences, University of Dundee, Dundee, DD1 5EH, UK
| | - Victoria H Cowling
- Centre for Gene Regulation and Expression, School of Life Sciences, University of Dundee, Dundee, DD1 5EH, UK
| | - Andrei V Pisliakov
- Computational Biology, School of Life Sciences, University of Dundee, Dundee, DD1 5EH, UK.,Physics, School of Science and Engineering, University of Dundee, Dundee, DD1 4HN, UK
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32
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Valdés López JF, Velilla PA, Urcuqui-Inchima S. Chikungunya Virus and Zika Virus, Two Different Viruses Examined with a Common Aim: Role of Pattern Recognition Receptors on the Inflammatory Response. J Interferon Cytokine Res 2019; 39:507-521. [DOI: 10.1089/jir.2019.0058] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Affiliation(s)
| | - Paula Andrea Velilla
- Grupo Inmunovirología, Facultad de Medicina, Universidad de Antioquia UdeA, Medellín, Colombia
| | - Silvio Urcuqui-Inchima
- Grupo Inmunovirología, Facultad de Medicina, Universidad de Antioquia UdeA, Medellín, Colombia
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33
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Munir A, Banerjee A, Shuman S. NAD+-dependent synthesis of a 5'-phospho-ADP-ribosylated RNA/DNA cap by RNA 2'-phosphotransferase Tpt1. Nucleic Acids Res 2019; 46:9617-9624. [PMID: 30202863 PMCID: PMC6182162 DOI: 10.1093/nar/gky792] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2018] [Accepted: 08/24/2018] [Indexed: 11/13/2022] Open
Abstract
RNA 2′-phosphotransferase Tpt1 converts an internal RNA 2′-monophosphate to a 2′-OH via a two-step NAD+-dependent mechanism in which: (i) the 2′-phosphate attacks the C1″ of NAD+ to expel nicotinamide and form a 2′-phospho-ADP-ribosylated RNA intermediate; and (ii) the ADP-ribose O2″ attacks the phosphate of the RNA 2′-phospho-ADPR intermediate to expel the RNA 2′-OH and generate ADP-ribose 1″–2″ cyclic phosphate. Tpt1 is an essential component of the fungal tRNA splicing pathway that generates a unique 2′-PO4, 3′-5′ phosphodiester splice junction during tRNA ligation. The wide distribution of Tpt1 enzymes in taxa that have no fungal-type RNA ligase raises the prospect that Tpt1 might catalyze reactions other than RNA 2′-phosphate removal. A survey of Tpt1 enzymes from diverse sources reveals that whereas all of the Tpt1 enzymes are capable of NAD+-dependent conversion of an internal RNA 2′-PO4 to a 2′-OH (the canonical Tpt1 reaction), a subset of Tpt1 enzymes also catalyzed NAD+-dependent ADP-ribosylation of an RNA or DNA 5′-monophosphate terminus. Aeropyrum pernix Tpt1 (ApeTpt1) is particularly adept in this respect. One-step synthesis of a 5′-phospho-ADP-ribosylated cap structure by ApeTpt1 (with no subsequent 5′-phosphotransferase step) extends the repertoire of the Tpt1 enzyme family and the catalogue of ADP-ribosylation reactions involving nucleic acid acceptors.
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Affiliation(s)
- Annum Munir
- Molecular Biology Program, Sloan-Kettering Institute, New York, NY 10065, USA
| | - Ankan Banerjee
- Molecular Biology Program, Sloan-Kettering Institute, New York, NY 10065, USA
| | - Stewart Shuman
- Molecular Biology Program, Sloan-Kettering Institute, New York, NY 10065, USA
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34
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Boulias K, Toczydłowska-Socha D, Hawley BR, Liberman N, Takashima K, Zaccara S, Guez T, Vasseur JJ, Debart F, Aravind L, Jaffrey SR, Greer EL. Identification of the m 6Am Methyltransferase PCIF1 Reveals the Location and Functions of m 6Am in the Transcriptome. Mol Cell 2019; 75:631-643.e8. [PMID: 31279658 DOI: 10.1016/j.molcel.2019.06.006] [Citation(s) in RCA: 160] [Impact Index Per Article: 32.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2018] [Revised: 04/08/2019] [Accepted: 06/02/2019] [Indexed: 12/21/2022]
Abstract
mRNAs are regulated by nucleotide modifications that influence their cellular fate. Two of the most abundant modified nucleotides are N6-methyladenosine (m6A), found within mRNAs, and N6,2'-O-dimethyladenosine (m6Am), which is found at the first transcribed nucleotide. Distinguishing these modifications in mapping studies has been difficult. Here, we identify and biochemically characterize PCIF1, the methyltransferase that generates m6Am. We find that PCIF1 binds and is dependent on the m7G cap. By depleting PCIF1, we generated transcriptome-wide maps that distinguish m6Am and m6A. We find that m6A and m6Am misannotations arise from mRNA isoforms with alternative transcription start sites (TSSs). These isoforms contain m6Am that maps to "internal" sites, increasing the likelihood of misannotation. We find that depleting PCIF1 does not substantially affect mRNA translation but is associated with reduced stability of a subset of m6Am-annotated mRNAs. The discovery of PCIF1 and our accurate mapping technique will facilitate future studies to characterize m6Am's function.
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Affiliation(s)
- Konstantinos Boulias
- Division of Newborn Medicine, Boston Children's Hospital, 300 Longwood Avenue, Boston, MA 02115, USA; Department of Pediatrics, Harvard Medical School, Boston, MA 02115, USA
| | - Diana Toczydłowska-Socha
- Department of Pharmacology, Weill Cornell Medicine, Cornell University, New York, NY 10065, USA; Laboratory of Bioinformatics and Protein Engineering, International Institute of Molecular and Cell Biology in Warsaw, 02-109 Warsaw, Poland
| | - Ben R Hawley
- Department of Pharmacology, Weill Cornell Medicine, Cornell University, New York, NY 10065, USA
| | - Noa Liberman
- Division of Newborn Medicine, Boston Children's Hospital, 300 Longwood Avenue, Boston, MA 02115, USA; Department of Pediatrics, Harvard Medical School, Boston, MA 02115, USA
| | - Ken Takashima
- Division of Newborn Medicine, Boston Children's Hospital, 300 Longwood Avenue, Boston, MA 02115, USA; Department of Pediatrics, Harvard Medical School, Boston, MA 02115, USA
| | - Sara Zaccara
- Department of Pharmacology, Weill Cornell Medicine, Cornell University, New York, NY 10065, USA
| | - Théo Guez
- IBMM, Université de Montpellier, CNRS, ENSCM, Montpellier, France
| | | | - Françoise Debart
- IBMM, Université de Montpellier, CNRS, ENSCM, Montpellier, France
| | - L Aravind
- NCBI, National Library of Medicine, NIH, Bethesda, MD 20894, USA
| | - Samie R Jaffrey
- Department of Pharmacology, Weill Cornell Medicine, Cornell University, New York, NY 10065, USA.
| | - Eric Lieberman Greer
- Division of Newborn Medicine, Boston Children's Hospital, 300 Longwood Avenue, Boston, MA 02115, USA; Department of Pediatrics, Harvard Medical School, Boston, MA 02115, USA.
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35
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Galloway A, Cowling VH. mRNA cap regulation in mammalian cell function and fate. BIOCHIMICA ET BIOPHYSICA ACTA. GENE REGULATORY MECHANISMS 2019; 1862:270-279. [PMID: 30312682 PMCID: PMC6414751 DOI: 10.1016/j.bbagrm.2018.09.011] [Citation(s) in RCA: 123] [Impact Index Per Article: 24.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/28/2018] [Revised: 09/13/2018] [Accepted: 09/30/2018] [Indexed: 12/17/2022]
Abstract
In this review we explore the regulation of mRNA cap formation and its impact on mammalian cells. The mRNA cap is a highly methylated modification of the 5' end of RNA pol II-transcribed RNA. It protects RNA from degradation, recruits complexes involved in RNA processing, export and translation initiation, and marks cellular mRNA as "self" to avoid recognition by the innate immune system. The mRNA cap can be viewed as a unique mark which selects RNA pol II transcripts for specific processing and translation. Over recent years, examples of regulation of mRNA cap formation have emerged, induced by oncogenes, developmental pathways and during the cell cycle. These signalling pathways regulate the rate and extent of mRNA cap formation, resulting in changes in gene expression, cell physiology and cell function.
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Affiliation(s)
- Alison Galloway
- Centre for Gene Regulation and Expression, School of Life Sciences, University of Dundee, Dow Street, Dundee DD1 5EH, UK
| | - Victoria H Cowling
- Centre for Gene Regulation and Expression, School of Life Sciences, University of Dundee, Dow Street, Dundee DD1 5EH, UK.
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36
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Dimitrova DG, Teysset L, Carré C. RNA 2'-O-Methylation (Nm) Modification in Human Diseases. Genes (Basel) 2019; 10:E117. [PMID: 30764532 PMCID: PMC6409641 DOI: 10.3390/genes10020117] [Citation(s) in RCA: 96] [Impact Index Per Article: 19.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2018] [Revised: 01/28/2019] [Accepted: 01/30/2019] [Indexed: 12/24/2022] Open
Abstract
Nm (2'-O-methylation) is one of the most common modifications in the RNA world. It has the potential to influence the RNA molecules in multiple ways, such as structure, stability, and interactions, and to play a role in various cellular processes from epigenetic gene regulation, through translation to self versus non-self recognition. Yet, building scientific knowledge on the Nm matter has been hampered for a long time by the challenges in detecting and mapping this modification. Today, with the latest advancements in the area, more and more Nm sites are discovered on RNAs (tRNA, rRNA, mRNA, and small non-coding RNA) and linked to normal or pathological conditions. This review aims to synthesize the Nm-associated human diseases known to date and to tackle potential indirect links to some other biological defects.
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Affiliation(s)
- Dilyana G Dimitrova
- Sorbonne Université, Institut de Biologie Paris Seine, Centre National de la Recherche Scientifique, Transgenerational Epigenetics & Small RNA Biology, Laboratoire de Biologie du Développement, 75005 Paris, France.
| | - Laure Teysset
- Sorbonne Université, Institut de Biologie Paris Seine, Centre National de la Recherche Scientifique, Transgenerational Epigenetics & Small RNA Biology, Laboratoire de Biologie du Développement, 75005 Paris, France.
| | - Clément Carré
- Sorbonne Université, Institut de Biologie Paris Seine, Centre National de la Recherche Scientifique, Transgenerational Epigenetics & Small RNA Biology, Laboratoire de Biologie du Développement, 75005 Paris, France.
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37
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FTSJ3 is an RNA 2'-O-methyltransferase recruited by HIV to avoid innate immune sensing. Nature 2019; 565:500-504. [PMID: 30626973 DOI: 10.1038/s41586-018-0841-4] [Citation(s) in RCA: 138] [Impact Index Per Article: 27.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2017] [Accepted: 12/04/2018] [Indexed: 11/08/2022]
Abstract
In mammals, 2'-O-methylation of RNA is a molecular signature by which the cellular innate immune system distinguishes endogenous from exogenous messenger RNA1-3. However, the molecular functions of RNA 2'-O-methylation are not well understood. Here we have purified TAR RNA-binding protein (TRBP) and its interacting partners and identified a DICER-independent TRBP complex containing FTSJ3, a putative 2'-O-methyltransferase (2'O-MTase). In vitro and ex vivo experiments show that FTSJ3 is a 2'O-MTase that is recruited to HIV RNA through TRBP. Using RiboMethSeq analysis4, we identified predominantly FTSJ3-dependent 2'-O-methylations at specific residues on the viral genome. HIV-1 viruses produced in FTSJ3 knockdown cells show reduced 2'-O-methylation and trigger expression of type 1 interferons (IFNs) in human dendritic cells through the RNA sensor MDA5. This induction of IFN-α and IFN-β leads to a reduction in HIV expression. We have identified an unexpected mechanism used by HIV-1 to evade innate immune recognition: the recruitment of the TRBP-FTSJ3 complex to viral RNA and its 2'-O-methylation.
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38
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Toczydlowska-Socha D, Zielinska MM, Kurkowska M, Astha, Almeida CF, Stefaniak F, Purta E, Bujnicki JM. Human RNA cap1 methyltransferase CMTr1 cooperates with RNA helicase DHX15 to modify RNAs with highly structured 5' termini. Philos Trans R Soc Lond B Biol Sci 2018; 373:rstb.2018.0161. [PMID: 30397098 PMCID: PMC6232587 DOI: 10.1098/rstb.2018.0161] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/05/2018] [Indexed: 11/23/2022] Open
Abstract
The 5′-cap structure, characteristic for RNA polymerase II-transcribed RNAs, plays important roles in RNA metabolism. In humans, RNA cap formation includes post-transcriptional modification of the first transcribed nucleotide by RNA cap1 methyltransferase (CMTr1). Here, we report that CMTr1 activity is hindered towards RNA substrates with highly structured 5′ termini. We found that CMTr1 binds ATP-dependent RNA DHX15 helicase and that this interaction, mediated by the G-patch domain of CMTr1, has an advantageous effect on CMTr1 activity towards highly structured RNA substrates. The effect of DHX15 helicase activity is consistent with the strength of the secondary structure that has to be removed for CMTr1 to access the 5′-terminal residues in a single-stranded conformation. This is, to our knowledge, the first demonstration of the involvement of DHX15 in post-transcriptional RNA modification, and the first example of a molecular process in which DHX15 directly affects the activity of another enzyme. Our findings suggest a new mechanism underlying the regulatory role of DHX15 in the RNA capping process. RNAs with highly structured 5′ termini constitute a significant fraction of the human transcriptome. Hence, CMTr1–DHX15 cooperation is likely to be important for the metabolism of RNA polymerase II-transcribed RNAs. This article is part of the theme issue ‘5′ and 3′ modifications controlling RNA degradation’.
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Affiliation(s)
- Diana Toczydlowska-Socha
- Laboratory of Bioinformatics and Protein Engineering, International Institute of Molecular and Cell Biology, ul. ks. Trojdena 4, 02-109 Warsaw, Poland
| | - Magdalena M Zielinska
- Laboratory of Bioinformatics and Protein Engineering, International Institute of Molecular and Cell Biology, ul. ks. Trojdena 4, 02-109 Warsaw, Poland
| | - Malgorzata Kurkowska
- Laboratory of Bioinformatics and Protein Engineering, International Institute of Molecular and Cell Biology, ul. ks. Trojdena 4, 02-109 Warsaw, Poland
| | - Astha
- Laboratory of Bioinformatics and Protein Engineering, International Institute of Molecular and Cell Biology, ul. ks. Trojdena 4, 02-109 Warsaw, Poland
| | - Catarina F Almeida
- Laboratory of Bioinformatics and Protein Engineering, International Institute of Molecular and Cell Biology, ul. ks. Trojdena 4, 02-109 Warsaw, Poland
| | - Filip Stefaniak
- Laboratory of Bioinformatics and Protein Engineering, International Institute of Molecular and Cell Biology, ul. ks. Trojdena 4, 02-109 Warsaw, Poland
| | - Elzbieta Purta
- Laboratory of Bioinformatics and Protein Engineering, International Institute of Molecular and Cell Biology, ul. ks. Trojdena 4, 02-109 Warsaw, Poland
| | - Janusz M Bujnicki
- Laboratory of Bioinformatics and Protein Engineering, International Institute of Molecular and Cell Biology, ul. ks. Trojdena 4, 02-109 Warsaw, Poland .,Institute of Molecular Biology and Biotechnology, Faculty of Biology, Adam Mickiewicz University, ul. Umultowska 89, 61-614 Poznan, Poland
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39
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Inesta-Vaquera F, Chaugule VK, Galloway A, Chandler L, Rojas-Fernandez A, Weidlich S, Peggie M, Cowling VH. DHX15 regulates CMTR1-dependent gene expression and cell proliferation. Life Sci Alliance 2018; 1:e201800092. [PMID: 30079402 PMCID: PMC6071836 DOI: 10.26508/lsa.201800092] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
DHX15 helicase regulates CMTR1-dependent first transcribed nucleotide ribose O-2 methylation. CMTR1 contributes to mRNA cap formation by methylating the first transcribed nucleotide ribose at the O-2 position. mRNA cap O-2 methylation has roles in mRNA stabilisation and translation, and self-RNA tolerance in innate immunity. We report that CMTR1 is recruited to serine-5–phosphorylated RNA Pol II C-terminal domain, early in transcription. We isolated CMTR1 in a complex with DHX15, an RNA helicase functioning in splicing and ribosome biogenesis, and characterised it as a regulator of CMTR1. When DHX15 is bound, CMTR1 activity is repressed and the methyltransferase does not bind to RNA pol II. Conversely, CMTR1 activates DHX15 helicase activity, which is likely to impact several nuclear functions. In HCC1806 breast carcinoma cell line, the DHX15–CMTR1 interaction controls ribosome loading of a subset of mRNAs and regulates cell proliferation. The impact of the CMTR1–DHX15 interaction is complex and will depend on the relative expression of these enzymes and their interactors, and the cellular dependency on different RNA processing pathways.
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Affiliation(s)
- Francisco Inesta-Vaquera
- Centre for Gene Regulation and Expression, School of Life Sciences, University of Dundee, Dundee, UK
| | - Viduth K Chaugule
- Institute of Molecular, Cell and Systems Biology, School of Life Sciences, University of Glasgow, Glasgow, UK
| | - Alison Galloway
- Centre for Gene Regulation and Expression, School of Life Sciences, University of Dundee, Dundee, UK
| | - Laurel Chandler
- Nuffield Department of Clinical Neurosciences, Medical Sciences Division, University of Oxford, Oxford, UK
| | - Alejandro Rojas-Fernandez
- Center for Interdisciplinary Studies on the Nervous System and Institute of Medicine, Universidad Austral de Chile, Valdivia, Chile
| | - Simone Weidlich
- Division of Signal Transduction Therapies, School of Life Sciences, University of Dundee, Dundee, UK
| | - Mark Peggie
- Division of Signal Transduction Therapies, School of Life Sciences, University of Dundee, Dundee, UK
| | - Victoria H Cowling
- Centre for Gene Regulation and Expression, School of Life Sciences, University of Dundee, Dundee, UK
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40
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Toenshoff ER, Fields PD, Bourgeois YX, Ebert D. The End of a 60-year Riddle: Identification and Genomic Characterization of an Iridovirus, the Causative Agent of White Fat Cell Disease in Zooplankton. G3 (BETHESDA, MD.) 2018; 8:1259-1272. [PMID: 29487186 PMCID: PMC5873915 DOI: 10.1534/g3.117.300429] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/28/2017] [Accepted: 02/08/2018] [Indexed: 12/11/2022]
Abstract
The planktonic freshwater crustacean of the genus Daphnia are a model system for biomedical research and, in particular, invertebrate-parasite interactions. Up until now, no virus has been characterized for this system. Here we report the discovery of an iridovirus as the causative agent of White Fat Cell Disease (WFCD) in Daphnia WFCD is a highly virulent disease of Daphnia that can easily be cultured under laboratory conditions. Although it has been studied from sites across Eurasia for more than 60 years, its causative agent had not been described, nor had an iridovirus been connected to WFCD before now. Here we find that an iridovirus-the Daphnia iridescent virus 1 (DIV-1)-is the causative agent of WFCD. DIV-1 has a genome sequence of about 288 kbp, with 39% G+C content and encodes 367 predicted open reading frames. DIV-1 clusters together with other invertebrate iridoviruses but has by far the largest genome among all sequenced iridoviruses. Comparative genomics reveal that DIV-1 has apparently recently lost a substantial number of unique genes but has also gained genes by horizontal gene transfer from its crustacean host. DIV-1 represents the first invertebrate iridovirus that encodes proteins to purportedly cap RNA, and it contains unique genes for a DnaJ-like protein, a membrane glycoprotein and protein of the immunoglobulin superfamily, which may mediate host-pathogen interactions and pathogenicity. Our findings end a 60-year search for the causative agent of WFCD and add to our knowledge of iridovirus genomics and invertebrate-virus interactions.
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Affiliation(s)
- Elena R Toenshoff
- Basel University, Department of Environmental Sciences, Zoology, Vesalgasse 1, CH-4051 Basel, Switzerland
| | - Peter D Fields
- Basel University, Department of Environmental Sciences, Zoology, Vesalgasse 1, CH-4051 Basel, Switzerland
| | - Yann X Bourgeois
- Basel University, Department of Environmental Sciences, Zoology, Vesalgasse 1, CH-4051 Basel, Switzerland
| | - Dieter Ebert
- Basel University, Department of Environmental Sciences, Zoology, Vesalgasse 1, CH-4051 Basel, Switzerland
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41
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Barvík I, Rejman D, Panova N, Šanderová H, Krásný L. Non-canonical transcription initiation: the expanding universe of transcription initiating substrates. FEMS Microbiol Rev 2017; 41:131-138. [PMID: 27799279 DOI: 10.1093/femsre/fuw041] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/17/2016] [Indexed: 11/13/2022] Open
Abstract
RNA polymerase (RNAP) is the central enzyme of transcription of the genetic information from DNA into RNA. RNAP recognizes four main substrates: ATP, CTP, GTP and UTP. Experimental evidence from the past several years suggests that, besides these four NTPs, other molecules can be used to initiate transcription: (i) ribooligonucleotides (nanoRNAs) and (ii) coenzymes such as NAD+, NADH, dephospho-CoA and FAD. The presence of these molecules at the 5΄ ends of RNAs affects the properties of the RNA. Here, we discuss the expanding portfolio of molecules that can initiate transcription, their mechanism of incorporation, effects on RNA and cellular processes, and we present an outlook toward other possible initiation substrates.
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Affiliation(s)
- Ivan Barvík
- Division of Biomolecular Physics, Institute of Physics, Faculty of Mathematics and Physics, Charles University, Ke Karlovu 5, 121 16 Prague 2, Czech Republic
| | - Dominik Rejman
- Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences v. v. i., Flemingovo nám. 2, 166 10 Prague 6, Czech Republic
| | - Natalya Panova
- Institute of Microbiology, Czech Academy of Sciences v. v. i., Vídenská 1083, 142 20 Prague 4, Czech Republic
| | - Hana Šanderová
- Institute of Microbiology, Czech Academy of Sciences v. v. i., Vídenská 1083, 142 20 Prague 4, Czech Republic
| | - Libor Krásný
- Institute of Microbiology, Czech Academy of Sciences v. v. i., Vídenská 1083, 142 20 Prague 4, Czech Republic
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42
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Balyan R, Gund R, Ebenezer C, Khalsa JK, Verghese DA, Krishnamurthy T, George A, Bal V, Rath S, Chaudhry A. Modulation of Naive CD8 T Cell Response Features by Ligand Density, Affinity, and Continued Signaling via Internalized TCRs. THE JOURNAL OF IMMUNOLOGY 2017; 198:1823-1837. [PMID: 28100678 DOI: 10.4049/jimmunol.1600083] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2016] [Accepted: 12/20/2016] [Indexed: 01/08/2023]
Abstract
T cell response magnitudes increase with increasing antigenic dosage. However, it is unclear whether ligand density only modulates the proportions of responding ligand-specific T cells or also alters responses at the single cell level. Using brief (3 h) exposure of TCR-transgenic mouse CD8 T cells in vitro to varying densities of cognate peptide-MHC ligand followed by ligand-free culture in IL-2, we found that ligand density determined the frequencies of responding cells but not the expression levels of the early activation marker molecule, CD69. Cells with low glucose uptake capacity and low protein synthesis rates were less ligand-sensitive, implicating metabolic competence in the response heterogeneity of CD8 T cell populations. Although most responding cells proliferated, ligand density was associated with time of entry into proliferation and with the extent of cell surface TCR downmodulation. TCR internalization was associated, regardless of the ligand density, with rapidity of c-myc induction, loss of the cell cycle inhibitor p27kip1, metabolic reprogramming, and cell cycle entry. A low affinity peptide ligand behaved, regardless of ligand density, like a low density, high affinity ligand in all these parameters. Inhibition of signaling after ligand exposure selectively delayed proliferation in cells with internalized TCRs. Finally, internalized TCRs continued to signal and genetic modification of TCR internalization and trafficking altered the duration of signaling in a T cell hybridoma. Together, our findings indicate that heterogeneity among responding CD8 T cell populations in their ability to respond to TCR-mediated stimulation and internalize TCRs mediates detection of ligand density or affinity, contributing to graded response magnitudes.
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Affiliation(s)
- Renu Balyan
- National Institute of Immunology, New Delhi 110067, India; and
| | - Rupali Gund
- National Institute of Immunology, New Delhi 110067, India; and
| | - Chitra Ebenezer
- National Institute of Immunology, New Delhi 110067, India; and
| | | | | | | | - Anna George
- National Institute of Immunology, New Delhi 110067, India; and
| | - Vineeta Bal
- National Institute of Immunology, New Delhi 110067, India; and
| | - Satyajit Rath
- National Institute of Immunology, New Delhi 110067, India; and
| | - Ashutosh Chaudhry
- National Institute of Immunology, New Delhi 110067, India; and.,Memorial Sloan Kettering Cancer Center, New York, NY 10065
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43
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c-Myc co-ordinates mRNA cap methylation and ribosomal RNA production. Biochem J 2016; 474:377-384. [PMID: 27934633 PMCID: PMC5247799 DOI: 10.1042/bcj20160930] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2016] [Revised: 11/24/2016] [Accepted: 12/01/2016] [Indexed: 01/11/2023]
Abstract
The mRNA cap is a structure added to RNA pol II transcripts in eukaryotes, which recruits factors involved in RNA processing, nuclear export and translation initiation. RNA guanine-7 methyltransferase (RNMT)–RNA-activating miniprotein (RAM), the mRNA cap methyltransferase complex, completes the basic functional mRNA cap structure, cap 0, by methylating the cap guanosine. Here, we report that RNMT–RAM co-ordinates mRNA processing with ribosome production. Suppression of RNMT–RAM reduces synthesis of the 45S ribosomal RNA (rRNA) precursor. RNMT–RAM is required for c-Myc expression, a major regulator of RNA pol I, which synthesises 45S rRNA. Constitutive expression of c-Myc restores rRNA synthesis when RNMT–RAM is suppressed, indicating that RNMT–RAM controls rRNA production predominantly by controlling c-Myc expression. We report that RNMT–RAM is recruited to the ribosomal DNA locus, which may contribute to rRNA synthesis in certain contexts.
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44
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Loo CP, Snyder CM, Hill AB. Blocking Virus Replication during Acute Murine Cytomegalovirus Infection Paradoxically Prolongs Antigen Presentation and Increases the CD8+ T Cell Response by Preventing Type I IFN-Dependent Depletion of Dendritic Cells. THE JOURNAL OF IMMUNOLOGY 2016; 198:383-393. [PMID: 27872208 DOI: 10.4049/jimmunol.1600478] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/18/2016] [Accepted: 10/21/2016] [Indexed: 12/14/2022]
Abstract
Increasing amounts of pathogen replication usually lead to a proportionate increase in size and effector differentiation of the CD8+ T cell response, which is attributed to increased Ag and inflammation. Using a murine CMV that is highly sensitive to the antiviral drug famciclovir to modulate virus replication, we found that increased virus replication drove increased effector CD8+ T cell differentiation, as expected. Paradoxically, however, increased virus replication dramatically decreased the size of the CD8+ T cell response to two immunodominant epitopes. The decreased response was due to type I IFN-dependent depletion of conventional dendritic cells and could be reproduced by specific depletion of dendritic cells from day 2 postinfection or by sterile induction of type I IFN. Increased virus replication and type I IFN specifically inhibited the response to two immunodominant epitopes that are known to be dependent on Ag cross-presented by DCs, but they did not inhibit the response to "inflationary" epitopes whose responses can be sustained by infected nonhematopoietic cells. Our results show that type I IFN can suppress CD8+ T cell responses to cross-presented Ag by depleting cross-presenting conventional dendritic cells.
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Affiliation(s)
- Christopher P Loo
- Department of Molecular Microbiology and Immunology, Oregon Health and Science University, Portland, OR 97239; and
| | - Christopher M Snyder
- Department of Microbiology and Immunology, Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA 19107
| | - Ann B Hill
- Department of Molecular Microbiology and Immunology, Oregon Health and Science University, Portland, OR 97239; and
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45
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Bautista BL, Devarajan P, McKinstry KK, Strutt TM, Vong AM, Jones MC, Kuang Y, Mott D, Swain SL. Short-Lived Antigen Recognition but Not Viral Infection at a Defined Checkpoint Programs Effector CD4 T Cells To Become Protective Memory. THE JOURNAL OF IMMUNOLOGY 2016; 197:3936-3949. [PMID: 27798159 DOI: 10.4049/jimmunol.1600838] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2016] [Accepted: 09/19/2016] [Indexed: 01/20/2023]
Abstract
Although memory CD4 T cells are critical for effective immunity to pathogens, the mechanisms underlying their generation are still poorly defined. We find that following murine influenza infection, most effector CD4 T cells undergo apoptosis unless they encounter cognate Ag at a defined stage near the peak of effector generation. Ag recognition at this memory checkpoint blocks default apoptosis and programs their transition to long-lived memory. Strikingly, we find that viral infection is not required, because memory formation can be restored by the addition of short-lived, Ag-pulsed APC at this checkpoint. The resulting memory CD4 T cells express an enhanced memory phenotype, have increased cytokine production, and provide protection against lethal influenza infection. Finally, we find that memory CD4 T cell formation following cold-adapted influenza vaccination is boosted when Ag is administered during this checkpoint. These findings imply that persistence of viral Ag presentation into the effector phase is the key factor that determines the efficiency of memory generation. We also suggest that administering Ag at this checkpoint may improve vaccine efficacy.
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Affiliation(s)
- Bianca L Bautista
- Department of Pathology, University of Massachusetts Medical School, Worcester, MA 01605
| | | | - K Kai McKinstry
- Department of Pathology, University of Massachusetts Medical School, Worcester, MA 01605
| | - Tara M Strutt
- Department of Pathology, University of Massachusetts Medical School, Worcester, MA 01605
| | - Allen M Vong
- Department of Pathology, University of Massachusetts Medical School, Worcester, MA 01605
| | - Michael C Jones
- Department of Pathology, University of Massachusetts Medical School, Worcester, MA 01605
| | - Yi Kuang
- Department of Pathology, University of Massachusetts Medical School, Worcester, MA 01605
| | - Daniel Mott
- Department of Pathology, University of Massachusetts Medical School, Worcester, MA 01605
| | - Susan L Swain
- Department of Pathology, University of Massachusetts Medical School, Worcester, MA 01605
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46
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The mRNA capping enzyme of Saccharomyces cerevisiae has dual specificity to interact with CTD of RNA Polymerase II. Sci Rep 2016; 6:31294. [PMID: 27503426 PMCID: PMC4977518 DOI: 10.1038/srep31294] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2016] [Accepted: 07/15/2016] [Indexed: 11/08/2022] Open
Abstract
RNA Polymerase II (RNAPII) uniquely possesses an extended carboxy terminal domain (CTD) on its largest subunit, Rpb1, comprising a repetitive Tyr1Ser2Pro3Thr4 Ser5Pro6Ser7 motif with potential phosphorylation sites. The phosphorylation of the CTD serves as a signal for the binding of various transcription regulators for mRNA biogenesis including the mRNA capping complex. In eukaryotes, the 5 prime capping of the nascent transcript is the first detectable mRNA processing event, and is crucial for the productive transcript elongation. The binding of capping enzyme, RNA guanylyltransferases to the transcribing RNAPII is known to be primarily facilitated by the CTD, phosphorylated at Ser5 (Ser5P). Here we report that the Saccharomyces cerevesiae RNA guanylyltransferase (Ceg1) has dual specificity and interacts not only with Ser5P but also with Ser7P of the CTD. The Ser7 of CTD is essential for the unconditional growth and efficient priming of the mRNA capping complex. The Arg159 and Arg185 of Ceg1 are the key residues that interact with the Ser5P, while the Lys175 with Ser7P of CTD. These interactions appear to be in a specific pattern of Ser5PSer7PSer5P in a tri-heptad CTD (YSPTSPPS YSPTSPSP YSPTSPPS) and provide molecular insights into the Ceg1-CTD interaction for mRNA transcription.
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47
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Kim MT, Kurup SP, Starbeck-Miller GR, Harty JT. Manipulating Memory CD8 T Cell Numbers by Timed Enhancement of IL-2 Signals. THE JOURNAL OF IMMUNOLOGY 2016; 197:1754-61. [PMID: 27439516 DOI: 10.4049/jimmunol.1600641] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/12/2016] [Accepted: 06/27/2016] [Indexed: 01/06/2023]
Abstract
As a result of the growing burden of tumors and chronic infections, manipulating CD8 T cell responses for clinical use has become an important goal for immunologists. In this article, we show that dendritic cell (DC) immunization coupled with relatively early (days 1-3) or late (days 4-6) administration of enhanced IL-2 signals increase peak effector CD8 T cell numbers, but only early IL-2 signals enhance memory numbers. IL-2 signals delivered at relatively late time points drive terminal differentiation and marked Bim-mediated contraction and do not increase memory T cell numbers. In contrast, early IL-2 signals induce effector cell metabolic profiles that are more conducive to memory formation. Of note, downregulation of CD80 and CD86 was observed on DCs in vivo following early IL-2 treatment. Mechanistically, early IL-2 treatment enhanced CTLA-4 expression on regulatory T cells, and CTLA-4 blockade alongside IL-2 treatment in vivo prevented the decrease in CD80 and CD86, supporting a cell-extrinsic role for CTLA-4 in downregulating B7 ligand expression on DCs. Finally, DC immunization followed by early IL-2 treatment and anti-CTLA-4 blockade resulted in lower memory CD8 T cell numbers compared with the DC+early IL-2 treatment group. These data suggest that curtailed signaling through the B7-CD28 costimulatory axis during CD8 T cell activation limits terminal differentiation and preserves memory CD8 T cell formation; thus, it should be considered in future T cell-vaccination strategies.
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Affiliation(s)
- Marie T Kim
- Interdisciplinary Program in Immunology, University of Iowa, Iowa City, IA 52242; Carver College of Medicine, University of Iowa, Iowa City, IA 52242
| | - Samarchith P Kurup
- Department of Microbiology, University of Iowa, Iowa City, IA 52242; and
| | | | - John T Harty
- Interdisciplinary Program in Immunology, University of Iowa, Iowa City, IA 52242; Department of Microbiology, University of Iowa, Iowa City, IA 52242; and Department of Pathology, University of Iowa, Iowa City, IA 52242
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48
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Varshney D, Petit AP, Bueren-Calabuig JA, Jansen C, Fletcher DA, Peggie M, Weidlich S, Scullion P, Pisliakov AV, Cowling VH. Molecular basis of RNA guanine-7 methyltransferase (RNMT) activation by RAM. Nucleic Acids Res 2016; 44:10423-10436. [PMID: 27422871 PMCID: PMC5137418 DOI: 10.1093/nar/gkw637] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2016] [Revised: 06/16/2016] [Accepted: 07/06/2016] [Indexed: 01/16/2023] Open
Abstract
Maturation and translation of mRNA in eukaryotes requires the addition of the 7-methylguanosine cap. In vertebrates, the cap methyltransferase, RNA guanine-7 methyltransferase (RNMT), has an activating subunit, RNMT-Activating Miniprotein (RAM). Here we report the first crystal structure of the human RNMT in complex with the activation domain of RAM. A relatively unstructured and negatively charged RAM binds to a positively charged surface groove on RNMT, distal to the active site. This results in stabilisation of a RNMT lobe structure which co-evolved with RAM and is required for RAM binding. Structure-guided mutagenesis and molecular dynamics simulations reveal that RAM stabilises the structure and positioning of the RNMT lobe and the adjacent α-helix hinge, resulting in optimal positioning of helix A which contacts substrates in the active site. Using biophysical and biochemical approaches, we observe that RAM increases the recruitment of the methyl donor, AdoMet (S-adenosyl methionine), to RNMT. Thus we report the mechanism by which RAM allosterically activates RNMT, allowing it to function as a molecular rheostat for mRNA cap methylation.
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Affiliation(s)
- Dhaval Varshney
- Centre for Gene Regulation and Expression, School of Life Sciences, University of Dundee, Dow Street, Dundee DD1 5EH, UK.,MRC Protein Phosphorylation and Ubiquitylation Unit, School of Life Sciences, University of Dundee, Dow Street, Dundee DD1 5EH, UK
| | - Alain-Pierre Petit
- Drug Discovery Unit, Division of Biological Chemistry and Drug Discovery, School of Life Sciences, University of Dundee, Dow Street, Dundee DD1 5EH, UK
| | - Juan A Bueren-Calabuig
- Computational Biology, School of Life Sciences, University of Dundee, Dow Street, Dundee DD1 5EH, UK.,Physics, School of Science and Engineering, University of Dundee, Nethergate, Dundee DD1 5EH, UK
| | - Chimed Jansen
- Drug Discovery Unit, Division of Biological Chemistry and Drug Discovery, School of Life Sciences, University of Dundee, Dow Street, Dundee DD1 5EH, UK
| | - Dan A Fletcher
- Drug Discovery Unit, Division of Biological Chemistry and Drug Discovery, School of Life Sciences, University of Dundee, Dow Street, Dundee DD1 5EH, UK
| | - Mark Peggie
- Division of Signal Transduction Therapies, School of Life Sciences, University of Dundee, Dow Street, Dundee DD1 5EH, UK
| | - Simone Weidlich
- Division of Signal Transduction Therapies, School of Life Sciences, University of Dundee, Dow Street, Dundee DD1 5EH, UK
| | - Paul Scullion
- Drug Discovery Unit, Division of Biological Chemistry and Drug Discovery, School of Life Sciences, University of Dundee, Dow Street, Dundee DD1 5EH, UK
| | - Andrei V Pisliakov
- Computational Biology, School of Life Sciences, University of Dundee, Dow Street, Dundee DD1 5EH, UK.,Physics, School of Science and Engineering, University of Dundee, Nethergate, Dundee DD1 5EH, UK
| | - Victoria H Cowling
- Centre for Gene Regulation and Expression, School of Life Sciences, University of Dundee, Dow Street, Dundee DD1 5EH, UK .,MRC Protein Phosphorylation and Ubiquitylation Unit, School of Life Sciences, University of Dundee, Dow Street, Dundee DD1 5EH, UK
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49
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Kaabinejadian S, McMurtrey CP, Kim S, Jain R, Bardet W, Schafer FB, Davenport JL, Martin AD, Diamond MS, Weidanz JA, Hansen TH, Hildebrand WH. Immunodominant West Nile Virus T Cell Epitopes Are Fewer in Number and Fashionably Late. THE JOURNAL OF IMMUNOLOGY 2016; 196:4263-73. [PMID: 27183642 DOI: 10.4049/jimmunol.1501821] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/13/2015] [Accepted: 03/20/2016] [Indexed: 12/23/2022]
Abstract
Class I HLA molecules mark infected cells for immune targeting by presenting pathogen-encoded peptides on the cell surface. Characterization of viral peptides unique to infected cells is important for understanding CD8(+) T cell responses and for the development of T cell-based immunotherapies. Having previously reported a series of West Nile virus (WNV) epitopes that are naturally presented by HLA-A*02:01, in this study we generated TCR mimic (TCRm) mAbs to three of these peptide/HLA complexes-the immunodominant SVG9 (E protein), the subdominant SLF9 (NS4B protein), and the immunorecessive YTM9 (NS3 protein)-and used these TCRm mAbs to stain WNV-infected cell lines and primary APCs. TCRm staining of WNV-infected cells demonstrated that the immunorecessive YTM9 appeared several hours earlier and at 5- to 10-fold greater density than the more immunogenic SLF9 and SVG9 ligands, respectively. Moreover, staining following inhibition of the TAP demonstrated that all three viral ligands were presented in a TAP-dependent manner despite originating from different cellular compartments. To our knowledge, this study represents the first use of TCRm mAbs to define the kinetics and magnitude of HLA presentation for a series of epitopes encoded by one virus, and the results depict a pattern whereby individual epitopes differ considerably in abundance and availability. The observations that immunodominant ligands can be found at lower levels and at later time points after infection suggest that a reevaluation of the factors that combine to shape T cell reactivity may be warranted.
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Affiliation(s)
- Saghar Kaabinejadian
- Department of Microbiology and Immunology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104
| | - Curtis P McMurtrey
- Department of Microbiology and Immunology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104
| | - Sojung Kim
- Department of Pathology and Immunology, Washington University School of Medicine, St Louis, MO 63110
| | - Rinki Jain
- Center for Immunotherapeutic Research, Texas Tech University Health Sciences Center School of Pharmacy, Abilene, TX 79601; Department of Immunotherapeutics and Biotechnology, Texas Tech University Health Sciences Center School of Pharmacy, Abilene, TX 79601; Receptor Logic, Inc., Abilene, TX 79601
| | - Wilfried Bardet
- Department of Microbiology and Immunology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104
| | - Fredda B Schafer
- Department of Microbiology and Immunology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104
| | | | | | - Michael S Diamond
- Department of Pathology and Immunology, Washington University School of Medicine, St Louis, MO 63110; Department of Medicine, Washington University School of Medicine, St Louis, MO 63110; and Department of Molecular Microbiology, Washington University School of Medicine, St Louis, MO 63110
| | - Jon A Weidanz
- Center for Immunotherapeutic Research, Texas Tech University Health Sciences Center School of Pharmacy, Abilene, TX 79601; Department of Immunotherapeutics and Biotechnology, Texas Tech University Health Sciences Center School of Pharmacy, Abilene, TX 79601; Receptor Logic, Inc., Abilene, TX 79601
| | - Ted H Hansen
- Department of Pathology and Immunology, Washington University School of Medicine, St Louis, MO 63110
| | - William H Hildebrand
- Department of Microbiology and Immunology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104;
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50
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Sutherland JM, Siddall NA, Hime GR, McLaughlin EA. RNA binding proteins in spermatogenesis: an in depth focus on the Musashi family. Asian J Androl 2016; 17:529-36. [PMID: 25851660 PMCID: PMC4492041 DOI: 10.4103/1008-682x.151397] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Controlled gene regulation during gamete development is vital for maintaining reproductive potential. During the complex process of mammalian spermatogenesis, male germ cells experience extended periods of the inactive transcription despite heavy translational requirements for continued growth and differentiation. Hence, spermatogenesis is highly reliant on mechanisms of posttranscriptional regulation of gene expression, facilitated by RNA binding proteins (RBPs), which remain abundantly expressed throughout this process. One such group of proteins is the Musashi family, previously identified as critical regulators of testis germ cell development and meiosis in Drosophila, and also shown to be vital to sperm development and reproductive potential in the mouse. This review describes the role and function of RBPs within the scope of male germ cell development, focusing on our recent knowledge of the Musashi proteins in spermatogenesis. The functional mechanisms utilized by RBPs within the cell are outlined in depth, and the significance of sub-cellular localization and stage-specific expression in relation to the mode and impact of posttranscriptional regulation is also highlighted. We emphasize the historical role of the Musashi family of RBPs in stem cell function and cell fate determination, as originally characterized in Drosophila and Xenopus, and conclude with our current understanding of the differential roles and functions of the mammalian Musashi proteins, Musashi-1 and Musashi-2, with a primary focus on our findings in spermatogenesis. This review highlights both the essential contribution of RBPs to posttranscriptional regulation and the importance of the Musashi family as master regulators of male gamete development.
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Affiliation(s)
| | | | | | - Eileen A McLaughlin
- School of Environmental and Life Sciences, University of Newcastle, Callaghan, NSW 2308, Australia
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