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Masinas MPD, Litsios A, Razdaibiedina A, Usaj M, Boone C, Andrews BJ. Expanding TheCellVision.org: a central repository for visualizing and mining high-content cell imaging projects. Genetics 2024; 227:iyae044. [PMID: 38518223 DOI: 10.1093/genetics/iyae044] [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: 01/16/2024] [Revised: 01/16/2024] [Accepted: 03/13/2024] [Indexed: 03/24/2024] Open
Abstract
We previously constructed TheCellVision.org, a central repository for visualizing and mining data from yeast high-content imaging projects. At its inception, TheCellVision.org housed two high-content screening (HCS) projects providing genome-scale protein abundance and localization information for the budding yeast Saccharomyces cerevisiae, as well as a comprehensive analysis of the morphology of its endocytic compartments upon systematic genetic perturbation of each yeast gene. Here, we report on the expansion of TheCellVision.org by the addition of two new HCS projects and the incorporation of new global functionalities. Specifically, TheCellVision.org now hosts images from the Cell Cycle Omics project, which describes genome-scale cell cycle-resolved dynamics in protein localization, protein concentration, gene expression, and translational efficiency in budding yeast. Moreover, it hosts PIFiA, a computational tool for image-based predictions of protein functional annotations. Across all its projects, TheCellVision.org now houses >800,000 microscopy images along with computational tools for exploring both the images and their associated datasets. Together with the newly added global functionalities, which include the ability to query genes in any of the hosted projects using either yeast or human gene names, TheCellVision.org provides an expanding resource for single-cell eukaryotic biology.
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Affiliation(s)
| | - Athanasios Litsios
- The Donnelly Centre, University of Toronto, Toronto, Ontario M5S 3E1, Canada
| | - Anastasia Razdaibiedina
- The Donnelly Centre, University of Toronto, Toronto, Ontario M5S 3E1, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario M5S 3E1, Canada
- Vector Institute for Artificial Intelligence, Toronto, Ontario M5G 1N1, Canada
| | - Matej Usaj
- The Donnelly Centre, University of Toronto, Toronto, Ontario M5S 3E1, Canada
| | - Charles Boone
- The Donnelly Centre, University of Toronto, Toronto, Ontario M5S 3E1, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario M5S 3E1, Canada
| | - Brenda J Andrews
- The Donnelly Centre, University of Toronto, Toronto, Ontario M5S 3E1, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario M5S 3E1, Canada
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2
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Litsios A, Grys BT, Kraus OZ, Friesen H, Ross C, Masinas MPD, Forster DT, Couvillion MT, Timmermann S, Billmann M, Myers C, Johnsson N, Churchman LS, Boone C, Andrews BJ. Proteome-scale movements and compartment connectivity during the eukaryotic cell cycle. Cell 2024; 187:1490-1507.e21. [PMID: 38452761 PMCID: PMC10947830 DOI: 10.1016/j.cell.2024.02.014] [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: 09/12/2023] [Revised: 12/01/2023] [Accepted: 02/12/2024] [Indexed: 03/09/2024]
Abstract
Cell cycle progression relies on coordinated changes in the composition and subcellular localization of the proteome. By applying two distinct convolutional neural networks on images of millions of live yeast cells, we resolved proteome-level dynamics in both concentration and localization during the cell cycle, with resolution of ∼20 subcellular localization classes. We show that a quarter of the proteome displays cell cycle periodicity, with proteins tending to be controlled either at the level of localization or concentration, but not both. Distinct levels of protein regulation are preferentially utilized for different aspects of the cell cycle, with changes in protein concentration being mostly involved in cell cycle control and changes in protein localization in the biophysical implementation of the cell cycle program. We present a resource for exploring global proteome dynamics during the cell cycle, which will aid in understanding a fundamental biological process at a systems level.
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Affiliation(s)
- Athanasios Litsios
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, ON M5S 3E1, Canada
| | - Benjamin T Grys
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, ON M5S 3E1, Canada; Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Oren Z Kraus
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, ON M5S 3E1, Canada; Department of Electrical and Computer Engineering, University of Toronto, Toronto, ON M5S 3G4, Canada
| | - Helena Friesen
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, ON M5S 3E1, Canada
| | - Catherine Ross
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, ON M5S 3E1, Canada; Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Myra Paz David Masinas
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, ON M5S 3E1, Canada
| | - Duncan T Forster
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, ON M5S 3E1, Canada; Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Mary T Couvillion
- Department of Genetics, Harvard Medical School, Boston, MA 02115, USA
| | - Stefanie Timmermann
- Institute of Molecular Genetics and Cell Biology, Department of Biology, Ulm University, Ulm 89081, Germany
| | - Maximilian Billmann
- Department of Computer Science and Engineering, University of Minnesota, Minneapolis, MN 55455, USA; Institute of Human Genetics, University of Bonn, School of Medicine and University Hospital Bonn, Bonn, Germany
| | - Chad Myers
- Department of Computer Science and Engineering, University of Minnesota, Minneapolis, MN 55455, USA
| | - Nils Johnsson
- Institute of Molecular Genetics and Cell Biology, Department of Biology, Ulm University, Ulm 89081, Germany
| | | | - Charles Boone
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, ON M5S 3E1, Canada; Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8, Canada; RIKEN Center for Sustainable Resource Science, Wako 351-0198 Saitama, Japan.
| | - Brenda J Andrews
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, ON M5S 3E1, Canada; Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8, Canada.
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3
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Schäfer JA, Sutandy FXR, Münch C. Omics-based approaches for the systematic profiling of mitochondrial biology. Mol Cell 2023; 83:911-926. [PMID: 36931258 DOI: 10.1016/j.molcel.2023.02.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2022] [Revised: 02/06/2023] [Accepted: 02/14/2023] [Indexed: 03/18/2023]
Abstract
Mitochondria are essential for cellular functions such as metabolism and apoptosis. They dynamically adapt to the changing environmental demands by adjusting their protein, nucleic acid, metabolite, and lipid contents. In addition, the mitochondrial components are modulated on different levels in response to changes, including abundance, activity, and interaction. A wide range of omics-based approaches has been developed to be able to explore mitochondrial adaptation and how mitochondrial function is compromised in disease contexts. Here, we provide an overview of the omics methods that allow us to systematically investigate the different aspects of mitochondrial biology. In addition, we show examples of how these methods have provided new biological insights. The emerging use of these toolboxes provides a more comprehensive understanding of the processes underlying mitochondrial function.
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Affiliation(s)
- Jasmin Adriana Schäfer
- Institute of Biochemistry II, Goethe University Frankfurt, Theodor-Stern-Kai 7, Haus 75, 60590 Frankfurt am Main, Germany
| | - F X Reymond Sutandy
- Institute of Biochemistry II, Goethe University Frankfurt, Theodor-Stern-Kai 7, Haus 75, 60590 Frankfurt am Main, Germany
| | - Christian Münch
- Institute of Biochemistry II, Goethe University Frankfurt, Theodor-Stern-Kai 7, Haus 75, 60590 Frankfurt am Main, Germany.
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4
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Hubble KA, Henry MF. DPC29 promotes post-initiation mitochondrial translation in Saccharomyces cerevisiae. Nucleic Acids Res 2023; 51:1260-1276. [PMID: 36620885 PMCID: PMC9943650 DOI: 10.1093/nar/gkac1229] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2022] [Revised: 12/07/2022] [Accepted: 12/09/2022] [Indexed: 01/10/2023] Open
Abstract
Mitochondrial ribosomes synthesize essential components of the oxidative phosphorylation (OXPHOS) system in a tightly regulated process. In the yeast Saccharomyces cerevisiae, mitochondrial mRNAs require specific translational activators, which orchestrate protein synthesis by recognition of their target gene's 5'-untranslated region (UTR). Most of these yeast genes lack orthologues in mammals, and only one such gene-specific translational activator has been proposed in humans-TACO1. The mechanism by which TACO1 acts is unclear because mammalian mitochondrial mRNAs do not have significant 5'-UTRs, and therefore must promote translation by alternative mechanisms. In this study, we examined the role of the TACO1 orthologue in yeast. We found this 29 kDa protein to be a general mitochondrial translation factor, Dpc29, rather than a COX1-specific translational activator. Its activity was necessary for the optimal expression of OXPHOS mtDNA reporters, and mutations within the mitoribosomal large subunit protein gene MRP7 produced a global reduction of mitochondrial translation in dpc29Δ cells, indicative of a general mitochondrial translation factor. Northern-based mitoribosome profiling of dpc29Δ cells showed higher footprint frequencies at the 3' ends of mRNAs, suggesting a role in translation post-initiation. Additionally, human TACO1 expressed at native levels rescued defects in dpc29Δ yeast strains, suggesting that the two proteins perform highly conserved functions.
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Affiliation(s)
- Kyle A Hubble
- Department of Molecular Biology, Rowan University School of Osteopathic Medicine, Stratford, NJ 08084, USA,Graduate School of Biomedical Sciences, Rowan University, Stratford, NJ 08084, USA
| | - Michael F Henry
- To whom correspondence should be addressed. Tel: +1 856 566 6970; Fax: +1 856 566 6291; E-mail:
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5
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Soto I, Couvillion M, Stirling Churchman L. Human Mitoribosome Profiling: A Re-engineered Approach Tailored to Study Mitochondrial Translation. Methods Mol Biol 2023; 2661:257-280. [PMID: 37166642 DOI: 10.1007/978-1-0716-3171-3_15] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
To understand the human mitochondrial translation process, tools are required to dissect this system at a global scale. The mechanisms and regulation of translation in mitochondria are different from those in the cytosol, and mitochondrial ribosomes have distinct biochemical properties. In this chapter, we describe in detail the modifications we have made to the ribosome profiling approach to adapt it to the unique characteristics of the human mitochondrial ribosome. This approach maximizes the fraction of mitochondrial ribosomes recovered, providing a snapshot of the mitochondrial translation landscape with minimal bias. We also describe the use of mouse lysate as an internal spike-in control for normalization, allowing quantification of global changes in translation across samples. Finally, we outline the bioinformatic pipelines to process the raw reads and identify mitoribosome A sites in the absence of untranslated regions flanking open reading frames. This method offers a subcodon-resolution time-sensitive global approach to explore the mitochondrial translation process in human cells.
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Affiliation(s)
- Iliana Soto
- Department of Genetics, Harvard Medical School, Boston, MA, USA
| | - Mary Couvillion
- Department of Genetics, Harvard Medical School, Boston, MA, USA
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6
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Kimura Y, Saito H, Osaki T, Ikegami Y, Wakigawa T, Ikeuchi Y, Iwasaki S. Mito-FUNCAT-FACS reveals cellular heterogeneity in mitochondrial translation. RNA (NEW YORK, N.Y.) 2022; 28:895-904. [PMID: 35256452 PMCID: PMC9074903 DOI: 10.1261/rna.079097.122] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/02/2022] [Accepted: 02/12/2022] [Indexed: 06/03/2023]
Abstract
Mitochondria possess their own genome that encodes components of oxidative phosphorylation (OXPHOS) complexes, and mitochondrial ribosomes within the organelle translate the mRNAs expressed from the mitochondrial genome. Given the differential OXPHOS activity observed in diverse cell types, cell growth conditions, and other circumstances, cellular heterogeneity in mitochondrial translation can be expected. Although individual protein products translated in mitochondria have been monitored, the lack of techniques that address the variation in overall mitochondrial protein synthesis in cell populations poses analytic challenges. Here, we adapted mitochondrial-specific fluorescent noncanonical amino acid tagging (FUNCAT) for use with fluorescence-activated cell sorting (FACS) and developed mito-FUNCAT-FACS. The click chemistry-compatible methionine analog L-homopropargylglycine (HPG) enabled the metabolic labeling of newly synthesized proteins. In the presence of cytosolic translation inhibitors, HPG was selectively incorporated into mitochondrial nascent proteins and conjugated to fluorophores via the click reaction (mito-FUNCAT). The application of in situ mito-FUNCAT to flow cytometry allowed us to separate changes in net mitochondrial translation activity from those of the organelle mass and detect variations in mitochondrial translation in cancer cells. Our approach provides a useful methodology for examining mitochondrial protein synthesis in individual cells.
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Affiliation(s)
- Yusuke Kimura
- Department of Computational Biology and Medical Sciences, Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa, Chiba 277-8561, Japan
- RNA Systems Biochemistry Laboratory, RIKEN Cluster for Pioneering Research, Wako, Saitama 351-0198, Japan
| | - Hironori Saito
- Department of Computational Biology and Medical Sciences, Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa, Chiba 277-8561, Japan
- RNA Systems Biochemistry Laboratory, RIKEN Cluster for Pioneering Research, Wako, Saitama 351-0198, Japan
| | - Tatsuya Osaki
- Institute of Industrial Science, The University of Tokyo, Meguro-ku, Tokyo 153-8505, Japan
| | - Yasuhiro Ikegami
- Institute of Industrial Science, The University of Tokyo, Meguro-ku, Tokyo 153-8505, Japan
| | - Taisei Wakigawa
- Department of Computational Biology and Medical Sciences, Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa, Chiba 277-8561, Japan
- RNA Systems Biochemistry Laboratory, RIKEN Cluster for Pioneering Research, Wako, Saitama 351-0198, Japan
| | - Yoshiho Ikeuchi
- Institute of Industrial Science, The University of Tokyo, Meguro-ku, Tokyo 153-8505, Japan
- Institute for AI and Beyond, The University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan
| | - Shintaro Iwasaki
- Department of Computational Biology and Medical Sciences, Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa, Chiba 277-8561, Japan
- RNA Systems Biochemistry Laboratory, RIKEN Cluster for Pioneering Research, Wako, Saitama 351-0198, Japan
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7
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Apostolopoulos A, Iwasaki S. Into the matrix: current methods for mitochondrial translation studies. J Biochem 2022; 171:379-387. [PMID: 35080613 DOI: 10.1093/jb/mvac005] [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: 12/27/2021] [Accepted: 01/18/2022] [Indexed: 11/12/2022] Open
Abstract
In addition to the cytoplasmic translation system, eukaryotic cells house additional protein synthesis machinery in mitochondria. The importance of this in organello translation is exemplified by clinical pathologies associated with mutations in mitochondrial translation factors. Although a detailed understanding of mitochondrial translation has long been awaited, quantitative, comprehensive, and spatiotemporal measurements have posed analytic challenges. The recent development of novel approaches for studying mitochondrial protein synthesis has overcome these issues and expands our understanding of the unique translation system. Here, we review the current technologies for the investigation of mitochondrial translation and the insights provided by their application.
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Affiliation(s)
- Antonios Apostolopoulos
- Department of Computational Biology and Medical Sciences, Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa, Chiba 277-8561, Japan.,RNA Systems Biochemistry Laboratory, RIKEN Cluster for Pioneering Research, Wako, Saitama 351-0198, Japan
| | - Shintaro Iwasaki
- Department of Computational Biology and Medical Sciences, Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa, Chiba 277-8561, Japan.,RNA Systems Biochemistry Laboratory, RIKEN Cluster for Pioneering Research, Wako, Saitama 351-0198, Japan
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8
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Shirokikh NE. Translation complex stabilization on messenger RNA and footprint profiling to study the RNA responses and dynamics of protein biosynthesis in the cells. Crit Rev Biochem Mol Biol 2021; 57:261-304. [PMID: 34852690 DOI: 10.1080/10409238.2021.2006599] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
During protein biosynthesis, ribosomes bind to messenger (m)RNA, locate its protein-coding information, and translate the nucleotide triplets sequentially as codons into the corresponding sequence of amino acids, forming proteins. Non-coding mRNA features, such as 5' and 3' untranslated regions (UTRs), start sites or stop codons of different efficiency, stretches of slower or faster code and nascent polypeptide interactions can alter the translation rates transcript-wise. Most of the homeostatic and signal response pathways of the cells converge on individual mRNA control, as well as alter the global translation output. Among the multitude of approaches to study translational control, one of the most powerful is to infer the locations of translational complexes on mRNA based on the mRNA fragments protected by these complexes from endonucleolytic hydrolysis, or footprints. Translation complex profiling by high-throughput sequencing of the footprints allows to quantify the transcript-wise, as well as global, alterations of translation, and uncover the underlying control mechanisms by attributing footprint locations and sizes to different configurations of the translational complexes. The accuracy of all footprint profiling approaches critically depends on the fidelity of footprint generation and many methods have emerged to preserve certain or multiple configurations of the translational complexes, often in challenging biological material. In this review, a systematic summary of approaches to stabilize translational complexes on mRNA for footprinting is presented and major findings are discussed. Future directions of translation footprint profiling are outlined, focusing on the fidelity and accuracy of inference of the native in vivo translation complex distribution on mRNA.
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Affiliation(s)
- Nikolay E Shirokikh
- Division of Genome Sciences and Cancer, The John Curtin School of Medical Research, The Australian National University, Canberra, Australia
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9
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Liu X, Shen S, Wu P, Li F, Liu X, Wang C, Gong Q, Wu J, Yao X, Zhang H, Shi Y. Structural insights into dimethylation of 12S rRNA by TFB1M: indispensable role in translation of mitochondrial genes and mitochondrial function. Nucleic Acids Res 2019; 47:7648-7665. [PMID: 31251801 PMCID: PMC6698656 DOI: 10.1093/nar/gkz505] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2018] [Revised: 05/16/2019] [Accepted: 06/12/2019] [Indexed: 12/15/2022] Open
Abstract
Mitochondria are essential molecular machinery for the maintenance of cellular energy supply by the oxidative phosphorylation system (OXPHOS). Mitochondrial transcription factor B1 (TFB1M) is a dimethyltransferase that maintains mitochondrial homeostasis by catalyzing dimethylation of two adjacent adenines located in helix45 (h45) of 12S rRNA. This m62A modification is indispensable for the assembly and maturation of human mitochondrial ribosomes. However, both the mechanism of TFB1M catalysis and the precise function of TFB1M in mitochondrial homeostasis are unknown. Here we report the crystal structures of a ternary complex of human (hs) TFB1M–h45–S-adenosyl-methionine and a binary complex hsTFB1M–h45. The structures revealed a distinct mode of hsTFB1M interaction with its rRNA substrate and with the initial enzymatic state involved in m62A modification. The suppression of hsTFB1M protein level or the overexpression of inactive hsTFB1M mutants resulted in decreased ATP production and reduced expression of components of the mitochondrial OXPHOS without affecting transcription of the corresponding genes and their localization to the mitochondria. Therefore, hsTFB1M regulated the translation of mitochondrial genes rather than their transcription via m62A modification in h45.
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Affiliation(s)
- Xiaodan Liu
- School of Life Sciences, University of Science & Technology of China, Hefei 230027, China.,Hefei National Laboratory for Physical Sciences at the Microscale, University of Science & Technology of China, Hefei 230027, China
| | - Shengqi Shen
- School of Life Sciences, University of Science & Technology of China, Hefei 230027, China.,Hefei National Laboratory for Physical Sciences at the Microscale, University of Science & Technology of China, Hefei 230027, China
| | - Pengzhi Wu
- School of Life Sciences, University of Science & Technology of China, Hefei 230027, China.,Hefei National Laboratory for Physical Sciences at the Microscale, University of Science & Technology of China, Hefei 230027, China
| | - Fudong Li
- School of Life Sciences, University of Science & Technology of China, Hefei 230027, China.,Hefei National Laboratory for Physical Sciences at the Microscale, University of Science & Technology of China, Hefei 230027, China
| | - Xing Liu
- School of Life Sciences, University of Science & Technology of China, Hefei 230027, China.,Hefei National Laboratory for Physical Sciences at the Microscale, University of Science & Technology of China, Hefei 230027, China
| | - Chongyuan Wang
- School of Life Sciences, University of Science & Technology of China, Hefei 230027, China.,Hefei National Laboratory for Physical Sciences at the Microscale, University of Science & Technology of China, Hefei 230027, China
| | - Qingguo Gong
- School of Life Sciences, University of Science & Technology of China, Hefei 230027, China.,Hefei National Laboratory for Physical Sciences at the Microscale, University of Science & Technology of China, Hefei 230027, China
| | - Jihui Wu
- School of Life Sciences, University of Science & Technology of China, Hefei 230027, China.,Hefei National Laboratory for Physical Sciences at the Microscale, University of Science & Technology of China, Hefei 230027, China
| | - Xuebiao Yao
- School of Life Sciences, University of Science & Technology of China, Hefei 230027, China.,Hefei National Laboratory for Physical Sciences at the Microscale, University of Science & Technology of China, Hefei 230027, China
| | - Huafeng Zhang
- School of Life Sciences, University of Science & Technology of China, Hefei 230027, China.,Hefei National Laboratory for Physical Sciences at the Microscale, University of Science & Technology of China, Hefei 230027, China
| | - Yunyu Shi
- School of Life Sciences, University of Science & Technology of China, Hefei 230027, China.,Hefei National Laboratory for Physical Sciences at the Microscale, University of Science & Technology of China, Hefei 230027, China
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10
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Doris SM, Chuang J, Viktorovskaya O, Murawska M, Spatt D, Churchman LS, Winston F. Spt6 Is Required for the Fidelity of Promoter Selection. Mol Cell 2018; 72:687-699.e6. [PMID: 30318445 DOI: 10.1016/j.molcel.2018.09.005] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2018] [Revised: 08/20/2018] [Accepted: 08/31/2018] [Indexed: 01/06/2023]
Abstract
Spt6 is a conserved factor that controls transcription and chromatin structure across the genome. Although Spt6 is viewed as an elongation factor, spt6 mutations in Saccharomyces cerevisiae allow elevated levels of transcripts from within coding regions, suggesting that Spt6 also controls initiation. To address the requirements for Spt6 in transcription and chromatin structure, we have combined four genome-wide approaches. Our results demonstrate that Spt6 represses transcription initiation at thousands of intragenic promoters. We characterize these intragenic promoters and find sequence features conserved with genic promoters. Finally, we show that Spt6 also regulates transcription initiation at most genic promoters and propose a model of initiation site competition to account for this. Together, our results demonstrate that Spt6 controls the fidelity of transcription initiation throughout the genome.
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Affiliation(s)
- Stephen M Doris
- Department of Genetics, Harvard Medical School, Boston, MA 02115, USA
| | - James Chuang
- Department of Genetics, Harvard Medical School, Boston, MA 02115, USA; Department of Biomedical Engineering, Boston University, Boston, MA 02215, USA
| | | | | | - Dan Spatt
- Department of Genetics, Harvard Medical School, Boston, MA 02115, USA
| | | | - Fred Winston
- Department of Genetics, Harvard Medical School, Boston, MA 02115, USA.
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11
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Eastman G, Smircich P, Sotelo-Silveira JR. Following Ribosome Footprints to Understand Translation at a Genome Wide Level. Comput Struct Biotechnol J 2018; 16:167-176. [PMID: 30069283 PMCID: PMC6066590 DOI: 10.1016/j.csbj.2018.04.001] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2018] [Revised: 04/06/2018] [Accepted: 04/10/2018] [Indexed: 12/11/2022] Open
Abstract
Protein translation is a key step in gene expression. The development of Ribosome Profiling has allowed the global analysis of this process at sub-codon resolution. In the last years the method has been applied to several models ranging from bacteria to mammalian cells yielding a surprising amount of insight on the mechanism and the regulation of translation. In this review we describe the key aspects of the experimental protocol and comment on the main conclusions raised in different models.
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Affiliation(s)
- Guillermo Eastman
- Department of Genomics, Instituto de Investigaciones Biológicas Clemente Estable, MEC, Av. Italia 3318, Montevideo, CP 11600, Uruguay
| | - Pablo Smircich
- Department of Genomics, Instituto de Investigaciones Biológicas Clemente Estable, MEC, Av. Italia 3318, Montevideo, CP 11600, Uruguay
- Laboratory of Molecular Interactions, Facultad de Ciencias, Universidad de la República, Iguá 4225, Montevideo, CP 11400, Uruguay
| | - José R. Sotelo-Silveira
- Department of Genomics, Instituto de Investigaciones Biológicas Clemente Estable, MEC, Av. Italia 3318, Montevideo, CP 11600, Uruguay
- Department of Cell and Molecular Biology, Facultad de Ciencias, Universidad de la República, Iguá 4225, Montevideo, CP 11400, Uruguay
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12
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Mazzoni-Putman SM, Stepanova AN. A Plant Biologist's Toolbox to Study Translation. FRONTIERS IN PLANT SCIENCE 2018; 9:873. [PMID: 30013583 PMCID: PMC6036148 DOI: 10.3389/fpls.2018.00873] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2018] [Accepted: 06/04/2018] [Indexed: 05/03/2023]
Abstract
Across a broad range of species and biological questions, more and more studies are incorporating translation data to better assess how gene regulation occurs at the level of protein synthesis. The inclusion of translation data improves upon, and has been shown to be more accurate than, transcriptional studies alone. However, there are many different techniques available to measure translation and it can be difficult, especially for young or aspiring scientists, to determine which methods are best applied in specific situations. We have assembled this review in order to enhance the understanding and promote the utilization of translational methods in plant biology. We cover a broad range of methods to measure changes in global translation (e.g., radiolabeling, polysome profiling, or puromycylation), translation of single genes (e.g., fluorescent reporter constructs, toeprinting, or ribosome density mapping), sequencing-based methods to uncover the entire translatome (e.g., Ribo-seq or translating ribosome affinity purification), and mass spectrometry-based methods to identify changes in the proteome (e.g., stable isotope labeling by amino acids in cell culture or bioorthogonal noncanonical amino acid tagging). The benefits and limitations of each method are discussed with a particular note of how applications from other model systems might be extended for use in plants. In order to make this burgeoning field more accessible to students and newer scientists, our review includes an extensive glossary to define key terms.
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13
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Gao F, Wesolowska M, Agami R, Rooijers K, Loayza-Puch F, Lawless C, Lightowlers RN, Chrzanowska-Lightowlers ZMA. Using mitoribosomal profiling to investigate human mitochondrial translation. Wellcome Open Res 2017; 2:116. [PMID: 29387808 PMCID: PMC5771143 DOI: 10.12688/wellcomeopenres.13119.2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/06/2017] [Indexed: 11/30/2022] Open
Abstract
Background: Gene expression in human mitochondria has various idiosyncratic features. One of these was recently revealed as the unprecedented recruitment of a mitochondrially-encoded tRNA as a structural component of the large mitoribosomal subunit. In porcine particles this is mt-tRNA
Phe whilst in humans it is mt-tRNA
Val. We have previously shown that when a mutation in mt-tRNA
Val causes very low steady state levels, there is preferential recruitment of mt-tRNA
Phe. We have investigated whether this altered mitoribosome affects intra-organellar protein synthesis. Methods: By using mitoribosomal profiling we have revealed aspects of mitoribosome behaviour with its template mt-mRNA under both normal conditions as well as those where the mitoribosome has incorporated mt-tRNA
Phe. Results: Analysis of the mitoribosome residency on transcripts under control conditions reveals that although mitochondria employ only 22 mt-tRNAs for protein synthesis, the use of non-canonical wobble base pairs at codon position 3 does not cause any measurable difference in mitoribosome occupancy irrespective of the codon. Comparison of the profile of aberrant mt-tRNA
Phe containing mitoribosomes with those of controls that integrate mt-tRNA
Val revealed that the impaired translation seen in the latter was not due to stalling on triplets encoding either of these amino acids. The alterations in mitoribosome interactions with start codons was not directly attributable to the either the use of non-cognate initiation codons or the presence or absence of 5’ leader sequences, except in the two bicistronic RNA units,
RNA7 and
RNA14 where the initiation sites are internal. Conclusions: These data report the power of mitoribosomal profiling in helping to understand the subtleties of mammalian mitochondrial protein synthesis. Analysis of profiles from the mutant mt-tRNA
Val cell line suggest that despite mt-tRNA
Phe being preferred in the porcine mitoribosome, its integration into the human counterpart results in a suboptimal structure that modifies its interaction with mt-mRNAs.
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Affiliation(s)
- Fei Gao
- The Wellcome Trust Centre for Mitochondrial Research, Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, UK
| | - Maria Wesolowska
- The Wellcome Trust Centre for Mitochondrial Research, Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, UK.,Immunocore Ltd, Oxford, UK
| | - Reuven Agami
- The Netherlands Cancer Institute, Amsterdam, Netherlands
| | - Koos Rooijers
- The Netherlands Cancer Institute, Amsterdam, Netherlands.,Hubrecht Institute, Utrecht, Netherlands
| | | | - Conor Lawless
- The Wellcome Centre for Mitochondrial Research, Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle upon Tyne, UK
| | - Robert N Lightowlers
- The Wellcome Centre for Mitochondrial Research, Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle upon Tyne, UK
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Gao F, Wesolowska M, Agami R, Rooijers K, Loayza-Puch F, Lawless C, Lightowlers RN, Chrzanowska-Lightowlers ZMA. Using mitoribosomal profiling to investigate human mitochondrial translation. Wellcome Open Res 2017. [PMID: 29387808 DOI: 10.12688/wellcomeopenres.13119.1] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Background: Gene expression in human mitochondria has various idiosyncratic features. One of these was recently revealed as the unprecedented recruitment of a mitochondrially-encoded tRNA as a structural component of the large mitoribosomal subunit. In porcine particles this is mt-tRNA Phe whilst in humans it is mt-tRNA Val. We have previously shown that when a mutation in mt-tRNA Val causes very low steady state levels, there is preferential recruitment of mt-tRNA Phe. We have investigated whether this altered mitoribosome affects intra-organellar protein synthesis. Methods: By using mitoribosomal profiling we have revealed aspects of mitoribosome behaviour with its template mt-mRNA under both normal conditions as well as those where the mitoribosome has incorporated mt-tRNA Phe. Results: Analysis of the mitoribosome residency on transcripts under control conditions reveals that although mitochondria employ only 22 mt-tRNAs for protein synthesis, the use of non-canonical wobble base pairs at codon position 3 does not cause any measurable difference in mitoribosome occupancy irrespective of the codon. Comparison of the profile of aberrant mt-tRNA Phe containing mitoribosomes with those of controls that integrate mt-tRNA Val revealed that the impaired translation seen in the latter was not due to stalling on triplets encoding either of these amino acids. The alterations in mitoribosome interactions with start codons was not directly attributable to the either the use of non-cognate initiation codons or the presence or absence of 5' leader sequences, except in the two bicistronic RNA units, RNA7 and RNA14 where the initiation sites are internal. Conclusions: These data report the power of mitoribosomal profiling in helping to understand the subtleties of mammalian mitochondrial protein synthesis. Analysis of profiles from the mutant mt-tRNA Val cell line suggest that despite mt-tRNA Phe being preferred in the porcine mitoribosome, its integration into the human counterpart results in a suboptimal structure that modifies its interaction with mt-mRNAs.
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Affiliation(s)
- Fei Gao
- The Wellcome Trust Centre for Mitochondrial Research, Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, UK
| | - Maria Wesolowska
- The Wellcome Trust Centre for Mitochondrial Research, Institute of Neuroscience, Newcastle University, Newcastle upon Tyne, UK.,Immunocore Ltd, Oxford, UK
| | - Reuven Agami
- The Netherlands Cancer Institute, Amsterdam, Netherlands
| | - Koos Rooijers
- The Netherlands Cancer Institute, Amsterdam, Netherlands.,Hubrecht Institute, Utrecht, Netherlands
| | | | - Conor Lawless
- The Wellcome Centre for Mitochondrial Research, Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle upon Tyne, UK
| | - Robert N Lightowlers
- The Wellcome Centre for Mitochondrial Research, Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle upon Tyne, UK
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