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Jacobebbinghaus N, Lauersen KJ, Kruse O, Baier T. Bicistronic expression of nuclear transgenes in Chlamydomonas reinhardtii. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2024; 118:1400-1412. [PMID: 38415961 DOI: 10.1111/tpj.16677] [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: 07/28/2023] [Revised: 01/19/2024] [Accepted: 01/29/2024] [Indexed: 02/29/2024]
Abstract
In eukaryotic organisms, proteins are typically translated from monocistronic messenger RNAs containing a single coding sequence (CDS). However, recent long transcript sequencing identified 87 nuclear polycistronic mRNAs in Chlamydomonas reinhardtii natively carrying multiple co-expressed CDSs. In this study, we investigated the dynamics of 22 short intergenic sequences derived from these native polycistronic loci by their application in genetic constructs for synthetic transgene expression. A promising candidate sequence was identified based on the quantification of transformation efficiency and expression strength of a fluorescence reporter protein. Subsequently, the expression of independent proteins from one mRNA was verified by cDNA amplification and protein molecular mass characterization. We demonstrated engineered bicistronic expression in vivo to drive successful co-expression of several terpene synthases with the selection marker aphVIII. Bicistronic transgene design resulted in significantly increased (E)-α-bisabolene production of 7.95 mg L-1 from a single open reading frame, 18.1× fold higher than previous reports. Use of this strategy simplifies screening procedures for identification of high-level expressing transformants, does not require the application of additional fluorescence reporters, and reduces the nucleotide footprint compared to classical monocistronic expression cassettes. Although clear advantages for bicistronic transgene expression were observed, this strategy was found to be limited to the aphVIII marker, and further studies are necessary to gain insights into the underlying mechanism that uniquely permits this co-expression from the algal nuclear genome.
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Affiliation(s)
- Nick Jacobebbinghaus
- Algae Biotechnology and Bioenergy, Faculty of Biology, Center for Biotechnology (CeBiTec), Bielefeld University, Bielefeld, Germany
| | - Kyle J Lauersen
- Bioengineering Program, Biological and Environmental Sciences and Engineering Division, King Abdullah University of Science and Technology (KAUST), Thuwal, Kingdom of Saudi Arabia
| | - Olaf Kruse
- Algae Biotechnology and Bioenergy, Faculty of Biology, Center for Biotechnology (CeBiTec), Bielefeld University, Bielefeld, Germany
| | - Thomas Baier
- Algae Biotechnology and Bioenergy, Faculty of Biology, Center for Biotechnology (CeBiTec), Bielefeld University, Bielefeld, Germany
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2
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Nichols C, Do-Thi VA, Peltier DC. Noncanonical microprotein regulation of immunity. Mol Ther 2024:S1525-0016(24)00324-1. [PMID: 38734902 DOI: 10.1016/j.ymthe.2024.05.021] [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: 02/08/2024] [Revised: 04/19/2024] [Accepted: 05/09/2024] [Indexed: 05/13/2024] Open
Abstract
The immune system is highly regulated but, when dysregulated, suboptimal protective or overly robust immune responses can lead to immune-mediated disorders. The genetic and molecular mechanisms of immune regulation are incompletely understood, impeding the development of more precise diagnostics and therapeutics for immune-mediated disorders. Recently, thousands of previously unrecognized noncanonical microprotein genes encoded by small open reading frames have been identified. Many of these microproteins perform critical functions, often in a cell- and context-specific manner. Several microproteins are now known to regulate immunity; however, the vast majority are uncharacterized. Therefore, illuminating what is often referred to as the "dark proteome," may present opportunities to tune immune responses more precisely. Here, we review noncanonical microprotein biology, highlight recently discovered examples regulating immunity, and discuss the potential and challenges of modulating dysregulated immune responses by targeting microproteins.
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Affiliation(s)
- Cydney Nichols
- Morris Green Scholars Program, Department of Pediatrics, Riley Hospital for Children, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Van Anh Do-Thi
- Division of Pediatric Hematology and Oncology, Department of Pediatrics, Herman B. Wells Center for Pediatric Research, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Daniel C Peltier
- Division of Pediatric Hematology and Oncology, Department of Pediatrics, Herman B. Wells Center for Pediatric Research, Indiana University School of Medicine, Indianapolis, IN 46202, USA; Simon Cancer Center, Indiana University School of Medicine, Indianapolis, IN 46202, USA.
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3
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Cutolo EA, Caferri R, Campitiello R, Cutolo M. The Clinical Promise of Microalgae in Rheumatoid Arthritis: From Natural Compounds to Recombinant Therapeutics. Mar Drugs 2023; 21:630. [PMID: 38132951 PMCID: PMC10745133 DOI: 10.3390/md21120630] [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: 10/17/2023] [Revised: 12/04/2023] [Accepted: 12/05/2023] [Indexed: 12/23/2023] Open
Abstract
Rheumatoid arthritis (RA) is an invalidating chronic autoimmune disorder characterized by joint inflammation and progressive bone damage. Dietary intervention is an important component in the treatment of RA to mitigate oxidative stress, a major pathogenic driver of the disease. Alongside traditional sources of antioxidants, microalgae-a diverse group of photosynthetic prokaryotes and eukaryotes-are emerging as anti-inflammatory and immunomodulatory food supplements. Several species accumulate therapeutic metabolites-mainly lipids and pigments-which interfere in the pro-inflammatory pathways involved in RA and other chronic inflammatory conditions. The advancement of the clinical uses of microalgae requires the continuous exploration of phytoplankton biodiversity and chemodiversity, followed by the domestication of wild strains into reliable producers of said metabolites. In addition, the tractability of microalgal genomes offers unprecedented possibilities to establish photosynthetic microbes as light-driven biofactories of heterologous immunotherapeutics. Here, we review the evidence-based anti-inflammatory mechanisms of microalgal metabolites and provide a detailed coverage of the genetic engineering strategies to enhance the yields of endogenous compounds and to develop innovative bioproducts.
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Affiliation(s)
- Edoardo Andrea Cutolo
- Laboratory of Photosynthesis and Bioenergy, Department of Biotechnology, University of Verona, Strada le Grazie 15, 37134 Verona, Italy;
| | - Roberto Caferri
- Laboratory of Photosynthesis and Bioenergy, Department of Biotechnology, University of Verona, Strada le Grazie 15, 37134 Verona, Italy;
| | - Rosanna Campitiello
- Research Laboratory and Academic Division of Clinical Rheumatology, Department of Internal Medicine, IRCCS San Martino Polyclinic Hospital, University of Genoa, Viale Benedetto XV, 6, 16132 Genoa, Italy; (R.C.)
| | - Maurizio Cutolo
- Research Laboratory and Academic Division of Clinical Rheumatology, Department of Internal Medicine, IRCCS San Martino Polyclinic Hospital, University of Genoa, Viale Benedetto XV, 6, 16132 Genoa, Italy; (R.C.)
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4
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Dougan KE, Deng ZL, Wöhlbrand L, Reuse C, Bunk B, Chen Y, Hartlich J, Hiller K, John U, Kalvelage J, Mansky J, Neumann-Schaal M, Overmann J, Petersen J, Sanchez-Garcia S, Schmidt-Hohagen K, Shah S, Spröer C, Sztajer H, Wang H, Bhattacharya D, Rabus R, Jahn D, Chan CX, Wagner-Döbler I. Multi-omics analysis reveals the molecular response to heat stress in a "red tide" dinoflagellate. Genome Biol 2023; 24:265. [PMID: 37996937 PMCID: PMC10666404 DOI: 10.1186/s13059-023-03107-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Accepted: 11/10/2023] [Indexed: 11/25/2023] Open
Abstract
BACKGROUND "Red tides" are harmful algal blooms caused by dinoflagellate microalgae that accumulate toxins lethal to other organisms, including humans via consumption of contaminated seafood. These algal blooms are driven by a combination of environmental factors including nutrient enrichment, particularly in warm waters, and are increasingly frequent. The molecular, regulatory, and evolutionary mechanisms that underlie the heat stress response in these harmful bloom-forming algal species remain little understood, due in part to the limited genomic resources from dinoflagellates, complicated by the large sizes of genomes, exhibiting features atypical of eukaryotes. RESULTS We present the de novo assembled genome (~ 4.75 Gbp with 85,849 protein-coding genes), transcriptome, proteome, and metabolome from Prorocentrum cordatum, a globally abundant, bloom-forming dinoflagellate. Using axenic algal cultures, we study the molecular mechanisms that underpin the algal response to heat stress, which is relevant to current ocean warming trends. We present the first evidence of a complementary interplay between RNA editing and exon usage that regulates the expression and functional diversity of biomolecules, reflected by reduction in photosynthesis, central metabolism, and protein synthesis. These results reveal genomic signatures and post-transcriptional regulation for the first time in a pelagic dinoflagellate. CONCLUSIONS Our multi-omics analyses uncover the molecular response to heat stress in an important bloom-forming algal species, which is driven by complex gene structures in a large, high-G+C genome, combined with multi-level transcriptional regulation. The dynamics and interplay of molecular regulatory mechanisms may explain in part how dinoflagellates diversified to become some of the most ecologically successful organisms on Earth.
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Affiliation(s)
- Katherine E Dougan
- Australian Centre for Ecogenomics, School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD, 4072, Australia
| | - Zhi-Luo Deng
- Helmholtz-Center for Infection Research (HZI), Inhoffenstraße 7, Braunschweig, 38124, Germany
| | - Lars Wöhlbrand
- Institute for Chemistry and Biology of the Marine Environment (ICBM), Carl von Ossietzky University of Oldenburg, 26129, Oldenburg, Germany
| | - Carsten Reuse
- Braunschweig Center for Systems Biology (BRICS), Technische Universität Braunschweig, Rebenring 56, 38106, Brunswick, Germany
| | - Boyke Bunk
- German Culture Collection for Microorganisms and Cell Cultures (DSMZ), Inhoffenstraße 7B, 38124, Braunschweig, Germany
| | - Yibi Chen
- Australian Centre for Ecogenomics, School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD, 4072, Australia
| | - Juliane Hartlich
- Braunschweig Center for Systems Biology (BRICS), Technische Universität Braunschweig, Rebenring 56, 38106, Brunswick, Germany
| | - Karsten Hiller
- Braunschweig Center for Systems Biology (BRICS), Technische Universität Braunschweig, Rebenring 56, 38106, Brunswick, Germany
| | - Uwe John
- Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, Am Handelshafen 12, 27570, Bremerhaven, Germany
- Helmholtz Institute for Functional Marine Biodiversity at the University of Oldenburg (HIFMB), Ammerländer Heerstraße 231, 26129, Oldenburg, Germany
| | - Jana Kalvelage
- Institute for Chemistry and Biology of the Marine Environment (ICBM), Carl von Ossietzky University of Oldenburg, 26129, Oldenburg, Germany
| | - Johannes Mansky
- Braunschweig Center for Systems Biology (BRICS), Technische Universität Braunschweig, Rebenring 56, 38106, Brunswick, Germany
| | - Meina Neumann-Schaal
- German Culture Collection for Microorganisms and Cell Cultures (DSMZ), Inhoffenstraße 7B, 38124, Braunschweig, Germany
| | - Jörg Overmann
- German Culture Collection for Microorganisms and Cell Cultures (DSMZ), Inhoffenstraße 7B, 38124, Braunschweig, Germany
| | - Jörn Petersen
- German Culture Collection for Microorganisms and Cell Cultures (DSMZ), Inhoffenstraße 7B, 38124, Braunschweig, Germany
| | - Selene Sanchez-Garcia
- Braunschweig Center for Systems Biology (BRICS), Technische Universität Braunschweig, Rebenring 56, 38106, Brunswick, Germany
| | - Kerstin Schmidt-Hohagen
- Braunschweig Center for Systems Biology (BRICS), Technische Universität Braunschweig, Rebenring 56, 38106, Brunswick, Germany
| | - Sarah Shah
- Australian Centre for Ecogenomics, School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD, 4072, Australia
| | - Cathrin Spröer
- German Culture Collection for Microorganisms and Cell Cultures (DSMZ), Inhoffenstraße 7B, 38124, Braunschweig, Germany
| | - Helena Sztajer
- Braunschweig Center for Systems Biology (BRICS), Technische Universität Braunschweig, Rebenring 56, 38106, Brunswick, Germany
| | - Hui Wang
- Braunschweig Center for Systems Biology (BRICS), Technische Universität Braunschweig, Rebenring 56, 38106, Brunswick, Germany
| | - Debashish Bhattacharya
- Department of Biochemistry and Microbiology, Rutgers University, New Brunswick, NJ, 08901, USA
| | - Ralf Rabus
- Institute for Chemistry and Biology of the Marine Environment (ICBM), Carl von Ossietzky University of Oldenburg, 26129, Oldenburg, Germany
| | - Dieter Jahn
- Braunschweig Center for Systems Biology (BRICS), Technische Universität Braunschweig, Rebenring 56, 38106, Brunswick, Germany
| | - Cheong Xin Chan
- Australian Centre for Ecogenomics, School of Chemistry and Molecular Biosciences, The University of Queensland, Brisbane, QLD, 4072, Australia.
| | - Irene Wagner-Döbler
- Braunschweig Center for Systems Biology (BRICS), Technische Universität Braunschweig, Rebenring 56, 38106, Brunswick, Germany.
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Kalvelage J, Wöhlbrand L, Schoon RA, Zink FM, Correll C, Senkler J, Eubel H, Hoppenrath M, Rhiel E, Braun HP, Winklhofer M, Klingl A, Rabus R. The enigmatic nucleus of the marine dinoflagellate Prorocentrum cordatum. mSphere 2023; 8:e0003823. [PMID: 37358287 PMCID: PMC10449503 DOI: 10.1128/msphere.00038-23] [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: 01/23/2023] [Accepted: 02/20/2023] [Indexed: 06/27/2023] Open
Abstract
The marine, bloom-forming dinoflagellate Prorocentrum cordatum CCMP 1329 (formerly P. minimum) has a genome atypical of eukaryotes, with a large size of ~4.15 Gbp, organized in plentiful, highly condensed chromosomes and packed in a dinoflagellate-specific nucleus (dinokaryon). Here, we apply microscopic and proteogenomic approaches to obtain new insights into this enigmatic nucleus of axenic P. cordatum. High-resolution focused ion beam/scanning electron microscopy analysis of the flattened nucleus revealed highest density of nuclear pores in the vicinity of the nucleolus, a total of 62 tightly packed chromosomes (~0.4-6.7 µm3), and interaction of several chromosomes with the nucleolus and other nuclear structures. A specific procedure for enriching intact nuclei was developed to enable proteomic analyses of soluble and membrane protein-enriched fractions. These were analyzed with geLC and shotgun approaches employing ion-trap and timsTOF (trapped-ion-mobility-spectrometry time-of-flight) mass spectrometers, respectively. This allowed identification of 4,052 proteins (39% of unknown function), out of which 418 were predicted to serve specific nuclear functions; additional 531 proteins of unknown function could be allocated to the nucleus. Compaction of DNA despite very low histone abundance could be accomplished by highly abundant major basic nuclear proteins (HCc2-like). Several nuclear processes including DNA replication/repair and RNA processing/splicing can be fairly well explained on the proteogenomic level. By contrast, transcription and composition of the nuclear pore complex remain largely elusive. One may speculate that the large group of potential nuclear proteins with currently unknown functions may serve yet to be explored functions in nuclear processes differing from those of typical eukaryotic cells. IMPORTANCE Dinoflagellates form a highly diverse group of unicellular microalgae. They provide keystone species for the marine ecosystem and stand out among others by their very large, unusually organized genomes embedded in the nuclei markedly different from other eukaryotic cells. Functional insights into nuclear and other cell biological structures and processes of dinoflagellates have long been hampered by the paucity of available genomic sequences. The here studied cosmopolitan P. cordatum belongs to the harmful algal bloom-forming, marine dinoflagellates and has a recently de novo assembled genome. We present a detailed 3D reconstruction of the P. cordatum nucleus together with comprehensive proteogenomic insights into the protein equipment mastering the broad spectrum of nuclear processes. This study significantly advances our understanding of mechanisms and evolution of the conspicuous dinoflagellate cell biology.
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Affiliation(s)
- Jana Kalvelage
- General and Molecular Microbiology, Institute for Chemistry and Biology of the Marine Environment (ICBM), Carl von Ossietzky University of Oldenburg, Oldenburg, Germany
| | - Lars Wöhlbrand
- General and Molecular Microbiology, Institute for Chemistry and Biology of the Marine Environment (ICBM), Carl von Ossietzky University of Oldenburg, Oldenburg, Germany
| | - Robin-Alexander Schoon
- General and Molecular Microbiology, Institute for Chemistry and Biology of the Marine Environment (ICBM), Carl von Ossietzky University of Oldenburg, Oldenburg, Germany
| | - Fiona-Marine Zink
- General and Molecular Microbiology, Institute for Chemistry and Biology of the Marine Environment (ICBM), Carl von Ossietzky University of Oldenburg, Oldenburg, Germany
| | - Christina Correll
- Plant Development, Botany, Ludwig-Maximilians-Universität München, Planegg, Martinsried, Germany
| | - Jennifer Senkler
- Plant Proteomics, Institute of Plant Genetics, Leibniz Universität Hannover, Hannover, Germany
| | - Holger Eubel
- Plant Proteomics, Institute of Plant Genetics, Leibniz Universität Hannover, Hannover, Germany
| | - Mona Hoppenrath
- Marine Biodiversity Research, Institute of Biology and Environmental Sciences (IBU), Carl von Ossietzky University of Oldenburg, Oldenburg, Germany
- Senckenberg am Meer, German Centre for Marine Biodiversity Research (DZMB), Wilhelmshaven, Germany
| | - Erhard Rhiel
- Planktology, Institute for Chemistry and Biology of the Marine Environment (ICBM), Carl von Ossietzky University of Oldenburg, Oldenburg, Germany
| | - Hans-Peter Braun
- Plant Proteomics, Institute of Plant Genetics, Leibniz Universität Hannover, Hannover, Germany
| | - Michael Winklhofer
- Sensory Biology of Animals, Institute of Biology and Environmental Sciences (IBU), Carl von Ossietzky University of Oldenburg, Oldenburg, Germany
- Research Center Neurosensory Science, Carl von Ossietzky University of Oldenburg, Oldenburg, Germany
| | - Andreas Klingl
- Plant Development, Botany, Ludwig-Maximilians-Universität München, Planegg, Martinsried, Germany
| | - Ralf Rabus
- General and Molecular Microbiology, Institute for Chemistry and Biology of the Marine Environment (ICBM), Carl von Ossietzky University of Oldenburg, Oldenburg, Germany
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6
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Yue Q, Meng J, Qiu Y, Yin M, Zhang L, Zhou W, An Z, Liu Z, Yuan Q, Sun W, Li C, Zhao H, Molnár I, Xu Y, Shi S. A polycistronic system for multiplexed and precalibrated expression of multigene pathways in fungi. Nat Commun 2023; 14:4267. [PMID: 37460548 DOI: 10.1038/s41467-023-40027-0] [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: 12/13/2022] [Accepted: 07/09/2023] [Indexed: 07/20/2023] Open
Abstract
Synthetic biology requires efficient systems that support the well-coordinated co-expression of multiple genes. Here, we discover a 9-bp nucleotide sequence that enables efficient polycistronic gene expression in yeasts and filamentous fungi. Coupling polycistronic expression to multiplexed, markerless, CRISPR/Cas9-based genome editing, we develop a strategy termed HACKing (Highly efficient and Accessible system by CracKing genes into the genome) for the assembly of multigene pathways. HACKing allows the expression level of each enzyme to be precalibrated by linking their translation to those of host proteins with predetermined abundances under the desired fermentation conditions. We validate HACKing by rapidly constructing highly efficient Saccharomyces cerevisiae cell factories that express 13 biosynthetic genes, and produce model endogenous (1,090.41 ± 80.92 mg L-1 squalene) or heterologous (1.04 ± 0.02 mg L-1 mogrol) terpenoid products. Thus, HACKing addresses the need of synthetic biology for predictability, simplicity, scalability, and speed upon fungal pathway engineering for valuable metabolites.
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Affiliation(s)
- Qun Yue
- Biotechnology Research Institute, The Chinese Academy of Agricultural Sciences, Beijing, China
| | - Jie Meng
- Beijing Advanced Innovation Center for Soft Matter Science and Engineering, College of Life Science and Technology, Beijing University of Chemical Technology, Beijing, China
| | - Yue Qiu
- Beijing Advanced Innovation Center for Soft Matter Science and Engineering, College of Life Science and Technology, Beijing University of Chemical Technology, Beijing, China
| | - Miaomiao Yin
- Biotechnology Research Institute, The Chinese Academy of Agricultural Sciences, Beijing, China
| | - Liwen Zhang
- Biotechnology Research Institute, The Chinese Academy of Agricultural Sciences, Beijing, China
| | - Weiping Zhou
- University of Chinese Academy of Sciences, Beijing, China
| | - Zhiqiang An
- Texas Therapeutics Institute, the Brown Foundation Institute of Molecular Medicine, University of Texas Health Science Center at Houston, Houston, USA
| | - Zihe Liu
- Beijing Advanced Innovation Center for Soft Matter Science and Engineering, College of Life Science and Technology, Beijing University of Chemical Technology, Beijing, China
| | - Qipeng Yuan
- Beijing Advanced Innovation Center for Soft Matter Science and Engineering, College of Life Science and Technology, Beijing University of Chemical Technology, Beijing, China
| | - Wentao Sun
- Key Lab for Industrial Biocatalysis, Ministry of Education, Department of Chemical Engineering, Tsinghua University, Beijing, China
| | - Chun Li
- Key Lab for Industrial Biocatalysis, Ministry of Education, Department of Chemical Engineering, Tsinghua University, Beijing, China
| | - Huimin Zhao
- Department of Chemical and Biomolecular Engineering, University of Illinois at Urbana-Champaign, Urbana, USA
| | - István Molnár
- VTT Technical Research Centre of Finland, Espoo, Finland.
| | - Yuquan Xu
- Biotechnology Research Institute, The Chinese Academy of Agricultural Sciences, Beijing, China.
| | - Shuobo Shi
- Beijing Advanced Innovation Center for Soft Matter Science and Engineering, College of Life Science and Technology, Beijing University of Chemical Technology, Beijing, China.
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7
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Smirnova J, Loerke J, Kleinau G, Schmidt A, Bürger J, Meyer EH, Mielke T, Scheerer P, Bock R, Spahn CMT, Zoschke R. Structure of the actively translating plant 80S ribosome at 2.2 Å resolution. NATURE PLANTS 2023; 9:987-1000. [PMID: 37156858 PMCID: PMC10281867 DOI: 10.1038/s41477-023-01407-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2022] [Accepted: 03/29/2023] [Indexed: 05/10/2023]
Abstract
In plant cells, translation occurs in three compartments: the cytosol, the plastids and the mitochondria. While the structures of the (prokaryotic-type) ribosomes in plastids and mitochondria are well characterized, high-resolution structures of the eukaryotic 80S ribosomes in the cytosol have been lacking. Here the structure of translating tobacco (Nicotiana tabacum) 80S ribosomes was solved by cryo-electron microscopy with a global resolution of 2.2 Å. The ribosome structure includes two tRNAs, decoded mRNA and the nascent peptide chain, thus providing insights into the molecular underpinnings of the cytosolic translation process in plants. The map displays conserved and plant-specific rRNA modifications and the positions of numerous ionic cofactors, and it uncovers the role of monovalent ions in the decoding centre. The model of the plant 80S ribosome enables broad phylogenetic comparisons that reveal commonalities and differences in the ribosomes of plants and those of other eukaryotes, thus putting our knowledge about eukaryotic translation on a firmer footing.
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Affiliation(s)
- Julia Smirnova
- Institute of Medical Physics and Biophysics, Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany.
| | - Justus Loerke
- Institute of Medical Physics and Biophysics, Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
| | - Gunnar Kleinau
- Institute of Medical Physics and Biophysics, Group Protein X-ray Crystallography and Signal Transduction, Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
| | - Andrea Schmidt
- Institute of Medical Physics and Biophysics, Group Protein X-ray Crystallography and Signal Transduction, Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
| | - Jörg Bürger
- Institute of Medical Physics and Biophysics, Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
- Microscopy and Cryo-Electron Microscopy Service Group, Max Planck Institute for Molecular Genetics, Berlin, Germany
| | - Etienne H Meyer
- Department III, Max Planck Institute of Molecular Plant Physiology, Potsdam-Golm, Germany
- Institut für Pflanzenphysiologie, Martin-Luther-Universität Halle-Wittenberg, Halle (Saale), Germany
| | - Thorsten Mielke
- Microscopy and Cryo-Electron Microscopy Service Group, Max Planck Institute for Molecular Genetics, Berlin, Germany
| | - Patrick Scheerer
- Institute of Medical Physics and Biophysics, Group Protein X-ray Crystallography and Signal Transduction, Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
| | - Ralph Bock
- Department III, Max Planck Institute of Molecular Plant Physiology, Potsdam-Golm, Germany.
| | - Christian M T Spahn
- Institute of Medical Physics and Biophysics, Charité-Universitätsmedizin Berlin, corporate member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany.
| | - Reimo Zoschke
- Department III, Max Planck Institute of Molecular Plant Physiology, Potsdam-Golm, Germany.
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8
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Titus-McQuillan JE, Nanni AV, McIntyre LM, Rogers RL. Estimating transcriptome complexities across eukaryotes. BMC Genomics 2023; 24:254. [PMID: 37170194 PMCID: PMC10173493 DOI: 10.1186/s12864-023-09326-0] [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: 02/02/2023] [Accepted: 04/20/2023] [Indexed: 05/13/2023] Open
Abstract
BACKGROUND Genomic complexity is a growing field of evolution, with case studies for comparative evolutionary analyses in model and emerging non-model systems. Understanding complexity and the functional components of the genome is an untapped wealth of knowledge ripe for exploration. With the "remarkable lack of correspondence" between genome size and complexity, there needs to be a way to quantify complexity across organisms. In this study, we use a set of complexity metrics that allow for evaluating changes in complexity using TranD. RESULTS We ascertain if complexity is increasing or decreasing across transcriptomes and at what structural level, as complexity varies. In this study, we define three metrics - TpG, EpT, and EpG- to quantify the transcriptome's complexity that encapsulates the dynamics of alternative splicing. Here we compare complexity metrics across 1) whole genome annotations, 2) a filtered subset of orthologs, and 3) novel genes to elucidate the impacts of orthologs and novel genes in transcript model analysis. Effective Exon Number (EEN) issued to compare the distribution of exon sizes within transcripts against random expectations of uniform exon placement. EEN accounts for differences in exon size, which is important because novel gene differences in complexity for orthologs and whole-transcriptome analyses are biased towards low-complexity genes with few exons and few alternative transcripts. CONCLUSIONS With our metric analyses, we are able to quantify changes in complexity across diverse lineages with greater precision and accuracy than previous cross-species comparisons under ortholog conditioning. These analyses represent a step toward whole-transcriptome analysis in the emerging field of non-model evolutionary genomics, with key insights for evolutionary inference of complexity changes on deep timescales across the tree of life. We suggest a means to quantify biases generated in ortholog calling and correct complexity analysis for lineage-specific effects. With these metrics, we directly assay the quantitative properties of newly formed lineage-specific genes as they lower complexity.
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Affiliation(s)
- James E Titus-McQuillan
- Department of Bioinformatics and Genomics, University of North Carolina at Charlotte, Charlotte, NC, 28223, USA.
| | - Adalena V Nanni
- Department of Molecular Genetics and Microbiology, University of Florida, Gainesville, FL, 32611, USA
- University of Florida Genetics Institute, University of Florida, Gainesville, FL, 32611, USA
| | - Lauren M McIntyre
- Department of Molecular Genetics and Microbiology, University of Florida, Gainesville, FL, 32611, USA
- University of Florida Genetics Institute, University of Florida, Gainesville, FL, 32611, USA
| | - Rebekah L Rogers
- Department of Bioinformatics and Genomics, University of North Carolina at Charlotte, Charlotte, NC, 28223, USA
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9
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Loan Young T, Chang Wang K, James Varley A, Li B. Clinical Delivery of Circular RNA: Lessons Learned from RNA Drug Development. Adv Drug Deliv Rev 2023; 197:114826. [PMID: 37088404 DOI: 10.1016/j.addr.2023.114826] [Citation(s) in RCA: 21] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2023] [Revised: 03/28/2023] [Accepted: 04/11/2023] [Indexed: 04/25/2023]
Abstract
Circular RNAs (circRNA) represent a distinct class of covalently closed-loop RNA molecules, which play diverse roles in regulating biological processes and disease states. The enhanced stability of synthetic circRNAs compared to their linear counterparts has recently garnered considerable research interest, paving the way for new therapeutic applications. While clinical circRNA technology is still in its early stages, significant advancements in mRNA technology offer valuable insights into its potential future applications. Two primary obstacles that must be addressed are the development of efficient production methods and the optimization of delivery systems. To expedite progress in this area, this review aims to provide an overview of the current state of knowledge on circRNA structure and function, outline recent techniques for synthesizing circRNAs, highlight key delivery strategies and applications, and discuss the current challenges and future prospects in the field of circRNA-based therapeutics.
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Affiliation(s)
- Tiana Loan Young
- Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, ON M5S 3M2, Canada
| | - Kevin Chang Wang
- Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, ON M5S 3M2, Canada
| | - Andrew James Varley
- Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, ON M5S 3M2, Canada
| | - Bowen Li
- Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, ON M5S 3M2, Canada; Institute of Biomedical Engineering, University of Toronto, Toronto, ON M5S 3M2, Canada; Princess Margaret Cancer Center, University Health Network, Toronto, ON M5G 2C1, Canada.
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10
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Payne ZL, Penny GM, Turner TN, Dutcher SK. A gap-free genome assembly of Chlamydomonas reinhardtii and detection of translocations induced by CRISPR-mediated mutagenesis. PLANT COMMUNICATIONS 2023; 4:100493. [PMID: 36397679 PMCID: PMC10030371 DOI: 10.1016/j.xplc.2022.100493] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/27/2022] [Revised: 10/26/2022] [Accepted: 11/15/2022] [Indexed: 05/04/2023]
Abstract
Genomic assemblies of the unicellular green alga Chlamydomonas reinhardtii have provided important resources for researchers. However, assembly errors, large gaps, and unplaced scaffolds as well as strain-specific variants currently impede many types of analysis. By combining PacBio HiFi and Oxford Nanopore long-read technologies, we generated a de novo genome assembly for strain CC-5816, derived from crosses of strains CC-125 and CC-124. Multiple methods of evaluating genome completeness and base-pair error rate suggest that the final telomere-to-telomere assembly is highly accurate. The CC-5816 assembly enabled previously difficult analyses that include characterization of the 17 centromeres, rDNA arrays on three chromosomes, and 56 insertions of organellar DNA into the nuclear genome. Using Nanopore sequencing, we identified sites of cytosine (CpG) methylation, which are enriched at centromeres. We analyzed CRISPR-Cas9 insertional mutants in the PF23 gene. Two of the three alleles produced progeny that displayed patterns of meiotic inviability that suggested the presence of a chromosomal aberration. Mapping Nanopore reads from pf23-2 and pf23-3 onto the CC-5816 genome showed that these two strains each carry a translocation that was initiated at the PF23 gene locus on chromosome 11 and joined with chromosomes 5 or 3, respectively. The translocations were verified by demonstrating linkage between loci on the two translocated chromosomes in meiotic progeny. The three pf23 alleles display the expected short-cilia phenotype, and immunoblotting showed that pf23-2 lacks the PF23 protein. Our CC-5816 genome assembly will undoubtedly provide an important tool for the Chlamydomonas research community.
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Affiliation(s)
- Zachary L Payne
- Department of Genetics, Washington University School of Medicine, Saint Louis, MO 63110, USA
| | - Gervette M Penny
- Department of Genetics, Washington University School of Medicine, Saint Louis, MO 63110, USA
| | - Tychele N Turner
- Department of Genetics, Washington University School of Medicine, Saint Louis, MO 63110, USA
| | - Susan K Dutcher
- Department of Genetics, Washington University School of Medicine, Saint Louis, MO 63110, USA.
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11
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Craig RJ, Gallaher SD, Shu S, Salomé PA, Jenkins JW, Blaby-Haas CE, Purvine SO, O’Donnell S, Barry K, Grimwood J, Strenkert D, Kropat J, Daum C, Yoshinaga Y, Goodstein DM, Vallon O, Schmutz J, Merchant SS. The Chlamydomonas Genome Project, version 6: Reference assemblies for mating-type plus and minus strains reveal extensive structural mutation in the laboratory. THE PLANT CELL 2023; 35:644-672. [PMID: 36562730 PMCID: PMC9940879 DOI: 10.1093/plcell/koac347] [Citation(s) in RCA: 14] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/02/2022] [Revised: 10/12/2022] [Accepted: 12/16/2022] [Indexed: 05/20/2023]
Abstract
Five versions of the Chlamydomonas reinhardtii reference genome have been produced over the last two decades. Here we present version 6, bringing significant advances in assembly quality and structural annotations. PacBio-based chromosome-level assemblies for two laboratory strains, CC-503 and CC-4532, provide resources for the plus and minus mating-type alleles. We corrected major misassemblies in previous versions and validated our assemblies via linkage analyses. Contiguity increased over ten-fold and >80% of filled gaps are within genes. We used Iso-Seq and deep RNA-seq datasets to improve structural annotations, and updated gene symbols and textual annotation of functionally characterized genes via extensive manual curation. We discovered that the cell wall-less classical reference strain CC-503 exhibits genomic instability potentially caused by deletion of the helicase RECQ3, with major structural mutations identified that affect >100 genes. We therefore present the CC-4532 assembly as the primary reference, although this strain also carries unique structural mutations and is experiencing rapid proliferation of a Gypsy retrotransposon. We expect all laboratory strains to harbor gene-disrupting mutations, which should be considered when interpreting and comparing experimental results. Collectively, the resources presented here herald a new era of Chlamydomonas genomics and will provide the foundation for continued research in this important reference organism.
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Affiliation(s)
- Rory J Craig
- California Institute for Quantitative Biosciences, University of California, Berkeley, California 94720, USA
- Institute of Ecology and Evolution, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3FL, UK
| | - Sean D Gallaher
- California Institute for Quantitative Biosciences, University of California, Berkeley, California 94720, USA
| | - Shengqiang Shu
- United States Department of Energy, Joint Genome Institute, Berkeley, California 94720, USA
| | - Patrice A Salomé
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, USA
- Institute for Genomics and Proteomics, University of California, Los Angeles, California 90095, USA
| | - Jerry W Jenkins
- HudsonAlpha Genome Sequencing Center, HudsonAlpha Institute for Biotechnology, Huntsville, Alabama 35806, USA
| | - Crysten E Blaby-Haas
- The Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - Samuel O Purvine
- Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, Washington 99354, USA
| | - Samuel O’Donnell
- Laboratory of Computational and Quantitative Biology, UMR 7238, CNRS, Institut de Biologie Paris-Seine, Sorbonne Université, Paris 75005, France
| | - Kerrie Barry
- United States Department of Energy, Joint Genome Institute, Berkeley, California 94720, USA
| | - Jane Grimwood
- HudsonAlpha Genome Sequencing Center, HudsonAlpha Institute for Biotechnology, Huntsville, Alabama 35806, USA
| | - Daniela Strenkert
- California Institute for Quantitative Biosciences, University of California, Berkeley, California 94720, USA
| | - Janette Kropat
- Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095, USA
| | - Chris Daum
- United States Department of Energy, Joint Genome Institute, Berkeley, California 94720, USA
| | - Yuko Yoshinaga
- United States Department of Energy, Joint Genome Institute, Berkeley, California 94720, USA
| | - David M Goodstein
- United States Department of Energy, Joint Genome Institute, Berkeley, California 94720, USA
| | - Olivier Vallon
- Unité Mixte de Recherche 7141, CNRS, Institut de Biologie Physico-Chimique, Sorbonne Université, Paris 75005, France
| | - Jeremy Schmutz
- United States Department of Energy, Joint Genome Institute, Berkeley, California 94720, USA
- HudsonAlpha Genome Sequencing Center, HudsonAlpha Institute for Biotechnology, Huntsville, Alabama 35806, USA
| | - Sabeeha S Merchant
- California Institute for Quantitative Biosciences, University of California, Berkeley, California 94720, USA
- Department of Molecular and Cell Biology, University of California, Berkeley, California 94720, USA
- Department of Plant and Microbial Biology, University of California, Berkeley, California 94720, USA
- Division of Environmental Genomics and Systems Biology, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
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12
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Kurihara Y, Makita Y, Kawauchi M, Kageyama A, Kuriyama T, Matsui M. Intergenic splicing-stimulated transcriptional readthrough is suppressed by nonsense-mediated mRNA decay in Arabidopsis. Commun Biol 2022; 5:1390. [PMID: 36539571 PMCID: PMC9768141 DOI: 10.1038/s42003-022-04348-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2022] [Accepted: 12/05/2022] [Indexed: 12/24/2022] Open
Abstract
Recent emerging evidence has shown that readthrough transcripts (RTs), including polycistronic mRNAs, are also transcribed in eukaryotes. However, the post-transcriptional regulation for these remains to be elucidated. Here, we identify 271 polycistronic RT-producing loci in Arabidopsis. Increased accumulation of RTs is detected in the nonsense-mediated mRNA decay (NMD)-deficient mutants compared with wild type, and the second open reading frames (ORFs) of bicistronic mRNAs are rarely translated in contrast to the first ORFs. Intergenic splicing (IS) events which occur between first and second genes are seen in 158 RTs. Splicing inhibition assays suggest that IS eliminates the chance of transcription termination at the polyadenylation sites of the first gene and promotes accumulation of RTs. These results indicate that RTs arise from genes whose transcription termination is relatively weak or attenuated by IS, but NMD selectively degrades them. Ultimately, this report presents a eukaryotic strategy for RNA metabolism.
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Affiliation(s)
- Yukio Kurihara
- grid.509461.f0000 0004 1757 8255Synthetic Genomics Research Group, RIKEN Center for Sustainable Resource Science, Suehiro-cho 1-7-22, Tsurumi-ku, Yokohama, Kanagawa 230-0045 Japan ,grid.26999.3d0000 0001 2151 536XDepartment of Life Sciences, Graduate School of Arts and Sciences, University of Tokyo, Komaba 3-8-1, Meguro-ku, Tokyo 153-8902 Japan
| | - Yuko Makita
- grid.509461.f0000 0004 1757 8255Synthetic Genomics Research Group, RIKEN Center for Sustainable Resource Science, Suehiro-cho 1-7-22, Tsurumi-ku, Yokohama, Kanagawa 230-0045 Japan ,grid.444244.60000 0004 0628 9167Faculty of Engineering, Maebashi Institute of Technology, Kamisadori 460-1, Maebashi, Gunma 371-0816 Japan
| | - Masaharu Kawauchi
- grid.509461.f0000 0004 1757 8255Synthetic Genomics Research Group, RIKEN Center for Sustainable Resource Science, Suehiro-cho 1-7-22, Tsurumi-ku, Yokohama, Kanagawa 230-0045 Japan
| | - Ami Kageyama
- grid.509461.f0000 0004 1757 8255Synthetic Genomics Research Group, RIKEN Center for Sustainable Resource Science, Suehiro-cho 1-7-22, Tsurumi-ku, Yokohama, Kanagawa 230-0045 Japan ,grid.268441.d0000 0001 1033 6139Graduate School of Nanobioscience, Department of Life and Environmental System Science, Yokohama City University, Yokohama, Kanagawa 236-0027 Japan
| | - Tomoko Kuriyama
- grid.509461.f0000 0004 1757 8255Synthetic Genomics Research Group, RIKEN Center for Sustainable Resource Science, Suehiro-cho 1-7-22, Tsurumi-ku, Yokohama, Kanagawa 230-0045 Japan
| | - Minami Matsui
- grid.509461.f0000 0004 1757 8255Synthetic Genomics Research Group, RIKEN Center for Sustainable Resource Science, Suehiro-cho 1-7-22, Tsurumi-ku, Yokohama, Kanagawa 230-0045 Japan ,grid.268441.d0000 0001 1033 6139Graduate School of Nanobioscience, Department of Life and Environmental System Science, Yokohama City University, Yokohama, Kanagawa 236-0027 Japan
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13
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Jürgens L, Wethmar K. The Emerging Role of uORF-Encoded uPeptides and HLA uLigands in Cellular and Tumor Biology. Cancers (Basel) 2022; 14:cancers14246031. [PMID: 36551517 PMCID: PMC9776223 DOI: 10.3390/cancers14246031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Revised: 11/29/2022] [Accepted: 11/30/2022] [Indexed: 12/13/2022] Open
Abstract
Recent technological advances have facilitated the detection of numerous non-canonical human peptides derived from regulatory regions of mRNAs, long non-coding RNAs, and other cryptic transcripts. In this review, we first give an overview of the classification of these novel peptides and summarize recent improvements in their annotation and detection by ribosome profiling, mass spectrometry, and individual experimental analysis. A large fraction of the novel peptides originates from translation at upstream open reading frames (uORFs) that are located within the transcript leader sequence of regular mRNA. In humans, uORF-encoded peptides (uPeptides) have been detected in both healthy and malignantly transformed cells and emerge as important regulators in cellular and immunological pathways. In the second part of the review, we focus on various functional implications of uPeptides. As uPeptides frequently act at the transition of translational regulation and individual peptide function, we describe the mechanistic modes of translational regulation through ribosome stalling, the involvement in cellular programs through protein interaction and complex formation, and their role within the human leukocyte antigen (HLA)-associated immunopeptidome as HLA uLigands. We delineate how malignant transformation may lead to the formation of novel uORFs, uPeptides, or HLA uLigands and explain their potential implication in tumor biology. Ultimately, we speculate on a potential use of uPeptides as peptide drugs and discuss how uPeptides and HLA uLigands may facilitate translational inhibition of oncogenic protein messages and immunotherapeutic approaches in cancer therapy.
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14
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Chen P, Michel AH, Zhang J. Transposon insertional mutagenesis of diverse yeast strains suggests coordinated gene essentiality polymorphisms. Nat Commun 2022; 13:1490. [PMID: 35314699 PMCID: PMC8938418 DOI: 10.1038/s41467-022-29228-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Accepted: 03/01/2022] [Indexed: 12/18/2022] Open
Abstract
Due to epistasis, the same mutation can have drastically different phenotypic consequences in different individuals. This phenomenon is pertinent to precision medicine as well as antimicrobial drug development, but its general characteristics are largely unknown. We approach this question by genome-wide assessment of gene essentiality polymorphism in 16 Saccharomyces cerevisiae strains using transposon insertional mutagenesis. Essentiality polymorphism is observed for 9.8% of genes, most of which have had repeated essentiality switches in evolution. Genes exhibiting essentiality polymorphism lean toward having intermediate numbers of genetic and protein interactions. Gene essentiality changes tend to occur concordantly among components of the same protein complex or metabolic pathway and among a group of over 100 mitochondrial proteins, revealing molecular machines or functional modules as units of gene essentiality variation. Most essential genes tolerate transposon insertions consistently among strains in one or more coding segments, delineating nonessential regions within essential genes.
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Affiliation(s)
- Piaopiao Chen
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI, 48109, USA
| | - Agnès H Michel
- Department of Biochemistry, University of Oxford, Oxford, OX1 3QU, UK
| | - Jianzhi Zhang
- Department of Ecology and Evolutionary Biology, University of Michigan, Ann Arbor, MI, 48109, USA.
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15
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Kelly S. The economics of organellar gene loss and endosymbiotic gene transfer. Genome Biol 2021; 22:345. [PMID: 34930424 PMCID: PMC8686548 DOI: 10.1186/s13059-021-02567-w] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2021] [Accepted: 12/06/2021] [Indexed: 01/09/2023] Open
Abstract
BACKGROUND The endosymbiosis of the bacterial progenitors of the mitochondrion and the chloroplast are landmark events in the evolution of life on Earth. While both organelles have retained substantial proteomic and biochemical complexity, this complexity is not reflected in the content of their genomes. Instead, the organellar genomes encode fewer than 5% of the genes found in living relatives of their ancestors. While many of the 95% of missing organellar genes have been discarded, others have been transferred to the host nuclear genome through a process known as endosymbiotic gene transfer. RESULTS Here, we demonstrate that the difference in the per-cell copy number of the organellar and nuclear genomes presents an energetic incentive to the cell to either delete organellar genes or transfer them to the nuclear genome. We show that, for the majority of transferred organellar genes, the energy saved by nuclear transfer exceeds the costs incurred from importing the encoded protein into the organelle where it can provide its function. Finally, we show that the net energy saved by endosymbiotic gene transfer can constitute an appreciable proportion of total cellular energy budgets and is therefore sufficient to impart a selectable advantage to the cell. CONCLUSION Thus, reduced cellular cost and improved energy efficiency likely played a role in the reductive evolution of mitochondrial and chloroplast genomes and the transfer of organellar genes to the nuclear genome.
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Affiliation(s)
- Steven Kelly
- Department of Plant Sciences, University of Oxford, South Parks Road, Oxford, OX1 3RB, UK.
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16
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Abstract
Recent human activity has profoundly transformed Earth biomes on a scale and at rates that are unprecedented. Given the central role of symbioses in ecosystem processes, functions, and services throughout the Earth biosphere, the impacts of human-driven change on symbioses are critical to understand. Symbioses are not merely collections of organisms, but co-evolved partners that arise from the synergistic combination and action of different genetic programs. They function with varying degrees of permanence and selection as emergent units with substantial potential for combinatorial and evolutionary innovation in both structure and function. Following an articulation of operational definitions of symbiosis and related concepts and characteristics of the Anthropocene, we outline a basic typology of anthropogenic change (AC) and a conceptual framework for how AC might mechanistically impact symbioses with select case examples to highlight our perspective. We discuss surprising connections between symbiosis and the Anthropocene, suggesting ways in which new symbioses could arise due to AC, how symbioses could be agents of ecosystem change, and how symbioses, broadly defined, of humans and “farmed” organisms may have launched the Anthropocene. We conclude with reflections on the robustness of symbioses to AC and our perspective on the importance of symbioses as ecosystem keystones and the need to tackle anthropogenic challenges as wise and humble stewards embedded within the system.
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Affiliation(s)
- Erik F Y Hom
- Department of Biology and Center for Biodiversity and Conservation Research, University of Mississippi, University, MS 38677 USA
| | - Alexandra S Penn
- Department of Sociology and Centre for Evaluation of Complexity Across the Nexus, University of Surrey, Guildford, Surrey, GU2 7XH UK
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17
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Chaux-Jukic F, O'Donnell S, Craig RJ, Eberhard S, Vallon O, Xu Z. Architecture and evolution of subtelomeres in the unicellular green alga Chlamydomonas reinhardtii. Nucleic Acids Res 2021; 49:7571-7587. [PMID: 34165564 PMCID: PMC8287924 DOI: 10.1093/nar/gkab534] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2021] [Revised: 06/01/2021] [Accepted: 06/08/2021] [Indexed: 02/06/2023] Open
Abstract
In most eukaryotes, subtelomeres are dynamic genomic regions populated by multi-copy sequences of different origins, which can promote segmental duplications and chromosomal rearrangements. However, their repetitive nature has complicated the efforts to sequence them, analyse their structure and infer how they evolved. Here, we use recent genome assemblies of Chlamydomonas reinhardtii based on long-read sequencing to comprehensively describe the subtelomere architecture of the 17 chromosomes of this model unicellular green alga. We identify three main repeated elements present at subtelomeres, which we call Sultan, Subtile and Suber, alongside three chromosome extremities with ribosomal DNA as the only identified component of their subtelomeres. The most common architecture, present in 27 out of 34 subtelomeres, is a heterochromatic array of Sultan elements adjacent to the telomere, followed by a transcribed Spacer sequence, a G-rich microsatellite and transposable elements. Sequence similarity analyses suggest that Sultan elements underwent segmental duplications within each subtelomere and rearranged between subtelomeres at a much lower frequency. Analysis of other green algae reveals species-specific repeated elements that are shared across subtelomeres, with an overall organization similar to C. reinhardtii. This work uncovers the complexity and evolution of subtelomere architecture in green algae.
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Affiliation(s)
- Frédéric Chaux-Jukic
- Sorbonne Université, CNRS, UMR7238, Institut de Biologie Paris-Seine, Laboratory of Computational and Quantitative Biology, 75005 Paris, France
| | - Samuel O'Donnell
- Sorbonne Université, CNRS, UMR7238, Institut de Biologie Paris-Seine, Laboratory of Computational and Quantitative Biology, 75005 Paris, France
| | - Rory J Craig
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, EH9 3FL, Edinburgh, UK
| | - Stephan Eberhard
- Sorbonne Université, CNRS, UMR7141, Institut de Biologie Physico-Chimique, Laboratory of Chloroplast Biology and Light-Sensing in Microalgae, 75005 Paris, France
| | - Olivier Vallon
- Sorbonne Université, CNRS, UMR7141, Institut de Biologie Physico-Chimique, Laboratory of Chloroplast Biology and Light-Sensing in Microalgae, 75005 Paris, France
| | - Zhou Xu
- Sorbonne Université, CNRS, UMR7238, Institut de Biologie Paris-Seine, Laboratory of Computational and Quantitative Biology, 75005 Paris, France
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18
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Craig RJ, Yushenova IA, Rodriguez F, Arkhipova IR. An ancient clade of Penelope-like retroelements with permuted domains is present in the green lineage and protists, and dominates many invertebrate genomes. Mol Biol Evol 2021; 38:5005-5020. [PMID: 34320655 PMCID: PMC8557442 DOI: 10.1093/molbev/msab225] [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] [Indexed: 12/28/2022] Open
Abstract
Penelope-like elements (PLEs) are an enigmatic clade of retrotransposons whose reverse transcriptases (RTs) share a most recent common ancestor with telomerase RTs. The single ORF of canonical endonuclease (EN)+ PLEs encodes RT and a C-terminal GIY–YIG EN that enables intrachromosomal integration, whereas EN− PLEs lack EN and are generally restricted to chromosome termini. EN+ PLEs have only been found in animals, except for one case of horizontal transfer to conifers, whereas EN− PLEs occur in several kingdoms. Here, we report a new, deep-branching PLE clade with a permuted domain order, whereby an N-terminal GIY–YIG EN is linked to a C-terminal RT by a short domain with a characteristic CxC motif. These N-terminal EN+ PLEs share a structural organization, including pseudo-LTRs and complex tandem/inverted insertions, with canonical EN+ PLEs from Penelope/Poseidon, Neptune, and Nematis clades, and show insertion bias for microsatellites, but lack canonical hammerhead ribozyme motifs. However, their phylogenetic distribution is much broader. The Naiads, found in numerous invertebrate phyla, can reach tens of thousands of copies per genome. In spiders and clams, Naiads independently evolved to encode selenoproteins containing multiple selenocysteines. Chlamys, which lack the CCHH motif universal to PLE ENs, occur in green algae, spike mosses (targeting ribosomal DNA), and slime molds. Unlike canonical PLEs, RTs of N-terminal EN+ PLEs contain the insertion-in-fingers domain (IFD), strengthening the link between PLEs and telomerases. Additionally, we describe Hydra, a novel metazoan C-terminal EN+ clade. Overall, we conclude that PLE diversity, taxonomic distribution, and abundance are comparable with non-LTR and LTR-retrotransposons.
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Affiliation(s)
- Rory J Craig
- Institute of Evolutionary Biology, University of Edinburgh, Edinburgh, UK
| | - Irina A Yushenova
- Josephine Bay Paul Center for Comparative Molecular Biology and Evolution, Marine Biological Laboratory, Woods Hole, MA, USA
| | - Fernando Rodriguez
- Josephine Bay Paul Center for Comparative Molecular Biology and Evolution, Marine Biological Laboratory, Woods Hole, MA, USA
| | - Irina R Arkhipova
- Josephine Bay Paul Center for Comparative Molecular Biology and Evolution, Marine Biological Laboratory, Woods Hole, MA, USA
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19
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Chaux-Jukic F, O'Donnell S, Craig RJ, Eberhard S, Vallon O, Xu Z. Architecture and evolution of subtelomeres in the unicellular green alga Chlamydomonas reinhardtii. Nucleic Acids Res 2021. [PMID: 34165564 DOI: 10.1101/2021.01.29.428817)] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/26/2023] Open
Abstract
In most eukaryotes, subtelomeres are dynamic genomic regions populated by multi-copy sequences of different origins, which can promote segmental duplications and chromosomal rearrangements. However, their repetitive nature has complicated the efforts to sequence them, analyse their structure and infer how they evolved. Here, we use recent genome assemblies of Chlamydomonas reinhardtii based on long-read sequencing to comprehensively describe the subtelomere architecture of the 17 chromosomes of this model unicellular green alga. We identify three main repeated elements present at subtelomeres, which we call Sultan, Subtile and Suber, alongside three chromosome extremities with ribosomal DNA as the only identified component of their subtelomeres. The most common architecture, present in 27 out of 34 subtelomeres, is a heterochromatic array of Sultan elements adjacent to the telomere, followed by a transcribed Spacer sequence, a G-rich microsatellite and transposable elements. Sequence similarity analyses suggest that Sultan elements underwent segmental duplications within each subtelomere and rearranged between subtelomeres at a much lower frequency. Analysis of other green algae reveals species-specific repeated elements that are shared across subtelomeres, with an overall organization similar to C. reinhardtii. This work uncovers the complexity and evolution of subtelomere architecture in green algae.
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Affiliation(s)
- Frédéric Chaux-Jukic
- Sorbonne Université, CNRS, UMR7238, Institut de Biologie Paris-Seine, Laboratory of Computational and Quantitative Biology, 75005 Paris, France
| | - Samuel O'Donnell
- Sorbonne Université, CNRS, UMR7238, Institut de Biologie Paris-Seine, Laboratory of Computational and Quantitative Biology, 75005 Paris, France
| | - Rory J Craig
- Institute of Evolutionary Biology, School of Biological Sciences, University of Edinburgh, EH9 3FL, Edinburgh, UK
| | - Stephan Eberhard
- Sorbonne Université, CNRS, UMR7141, Institut de Biologie Physico-Chimique, Laboratory of Chloroplast Biology and Light-Sensing in Microalgae, 75005 Paris, France
| | - Olivier Vallon
- Sorbonne Université, CNRS, UMR7141, Institut de Biologie Physico-Chimique, Laboratory of Chloroplast Biology and Light-Sensing in Microalgae, 75005 Paris, France
| | - Zhou Xu
- Sorbonne Université, CNRS, UMR7238, Institut de Biologie Paris-Seine, Laboratory of Computational and Quantitative Biology, 75005 Paris, France
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20
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Craig RJ, Hasan AR, Ness RW, Keightley PD. Comparative genomics of Chlamydomonas. THE PLANT CELL 2021; 33:1016-1041. [PMID: 33793842 PMCID: PMC8226300 DOI: 10.1093/plcell/koab026] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Accepted: 01/22/2021] [Indexed: 05/06/2023]
Abstract
Despite its role as a reference organism in the plant sciences, the green alga Chlamydomonas reinhardtii entirely lacks genomic resources from closely related species. We present highly contiguous and well-annotated genome assemblies for three unicellular C. reinhardtii relatives: Chlamydomonas incerta, Chlamydomonas schloesseri, and the more distantly related Edaphochlamys debaryana. The three Chlamydomonas genomes are highly syntenous with similar gene contents, although the 129.2 Mb C. incerta and 130.2 Mb C. schloesseri assemblies are more repeat-rich than the 111.1 Mb C. reinhardtii genome. We identify the major centromeric repeat in C. reinhardtii as a LINE transposable element homologous to Zepp (the centromeric repeat in Coccomyxa subellipsoidea) and infer that centromere locations and structure are likely conserved in C. incerta and C. schloesseri. We report extensive rearrangements, but limited gene turnover, between the minus mating type loci of these Chlamydomonas species. We produce an eight-species core-Reinhardtinia whole-genome alignment, which we use to identify several hundred false positive and missing genes in the C. reinhardtii annotation and >260,000 evolutionarily conserved elements in the C. reinhardtii genome. In summary, these resources will enable comparative genomics analyses for C. reinhardtii, significantly extending the analytical toolkit for this emerging model system.
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Affiliation(s)
| | - Ahmed R Hasan
- Department of Biology, University of Toronto Mississauga, Mississauga, Onatrio, Canada L5L 1C6
| | - Rob W Ness
- Department of Biology, University of Toronto Mississauga, Mississauga, Onatrio, Canada L5L 1C6
| | - Peter D Keightley
- School of Biological Sciences, Institute of Evolutionary Biology, University of Edinburgh, EH9 3FL Edinburgh, UK
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Identification of polycistronic transcriptional units and non-canonical introns in green algal chloroplasts based on long-read RNA sequencing data. BMC Genomics 2021; 22:298. [PMID: 33892645 PMCID: PMC8063479 DOI: 10.1186/s12864-021-07598-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2020] [Accepted: 04/11/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Chloroplasts are important semi-autonomous organelles in plants and algae. Unlike higher plants, the chloroplast genomes of green algal linage have distinct features both in organization and expression. Despite the architecture of chloroplast genome having been extensively studied in higher plants and several model species of algae, little is known about the transcriptional features of green algal chloroplast-encoded genes. RESULTS Based on full-length cDNA (Iso-Seq) sequencing, we identified widely co-transcribed polycistronic transcriptional units (PTUs) in the green alga Caulerpa lentillifera. In addition to clusters of genes from the same pathway, we identified a series of PTUs of up to nine genes whose function in the plastid is not understood. The RNA data further allowed us to confirm widespread expression of fragmented genes and conserved open reading frames, which are both important features in green algal chloroplast genomes. In addition, a newly fragmented gene specific to C. lentillifera was discovered, which may represent a recent gene fragmentation event in the chloroplast genome. With the newly annotated exon-intron boundary information, gene structural annotation was greatly improved across the siphonous green algae lineages. Our data also revealed a type of non-canonical Group II introns, with a deviant secondary structure and intronic ORFs lacking known splicing or mobility domains. These widespread introns have conserved positions in their genes and are excised precisely despite lacking clear consensus intron boundaries. CONCLUSION Our study fills important knowledge gaps in chloroplast genome organization and transcription in green algae, and provides new insights into expression of polycistronic transcripts, freestanding ORFs and fragmented genes in algal chloroplast genomes. Moreover, we revealed an unusual type of Group II intron with distinct features and conserved positions in Bryopsidales. Our data represents interesting additions to knowledge of chloroplast intron structure and highlights clusters of uncharacterized genes that probably play important roles in plastids.
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