1
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Meehan J, Ivens A, Grote S, Rodshagen T, Chen Z, Goode C, Sharma SK, Kumar V, Frese A, Goodall Z, McCleskey L, Sechrist R, Zeng L, Savill NJ, Rouskin S, Schnaufer A, McDermott SM, Cruz-Reyes J. KREH2 helicase represses ND7 mRNA editing in procyclic-stage Trypanosoma brucei by opposite modulation of canonical and 'moonlighting' gRNA utilization creating a proposed mRNA structure. Nucleic Acids Res 2024:gkae699. [PMID: 39149912 DOI: 10.1093/nar/gkae699] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2024] [Revised: 07/17/2024] [Accepted: 08/01/2024] [Indexed: 08/17/2024] Open
Abstract
Unknown factors regulate mitochondrial U-insertion/deletion (U-indel) RNA editing in procyclic-form (PCF) and bloodstream-form (BSF) T. brucei. This editing, directed by anti-sense gRNAs, creates canonical protein-encoding mRNAs and may developmentally control respiration. Canonical editing by gRNAs that specify protein-encoding mRNA sequences occurs amid massive non-canonical editing of unclear sources and biological significance. We found PCF-specific repression at a major early checkpoint in mRNA ND7, involving helicase KREH2-dependent opposite modulation of canonical and non-canonical 'terminator' gRNA utilization. Terminator-programmed editing derails canonical editing and installs proposed repressive structure in 30% of the ND7 transcriptome. BSF-to-PCF differentiation in vitro recreated this negative control. Remarkably, KREH2-RNAi knockdown relieved repression and increased editing progression by reverting canonical/terminator gRNA utilization. ND7 transcripts lacking early terminator-directed editing in PCF exhibited similar negative editing control along the mRNA sequence, suggesting global modulation of gRNA utilization fidelity. The terminator is a 'moonlighting' gRNA also associated with mRNA COX3 canonical editing, so the gRNA transcriptome seems multifunctional. Thus, KREH2 is the first identified repressor in developmental editing control. This and our prior work support a model whereby KREH2 activates or represses editing in a stage and substrate-specific manner. KREH2's novel dual role tunes mitochondrial gene expression in either direction during development.
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Affiliation(s)
- Joshua Meehan
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843, USA
| | - Alasdair Ivens
- Institute of Immunology and Infection Research, University of Edinburgh, Edinburgh, EH9 3FL, UK
| | - Scott Grote
- Department of Microbiology, Harvard Medical School, Boston, MA 02115, USA
| | - Tyler Rodshagen
- Center for Global Infectious Disease Research, Seattle Children's Research Institute, Seattle, WA 98109, USA
| | - Zihao Chen
- Institute of Immunology and Infection Research, University of Edinburgh, Edinburgh, EH9 3FL, UK
| | - Cody Goode
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843, USA
| | - Sunil K Sharma
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843, USA
| | - Vikas Kumar
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843, USA
| | - Addison Frese
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843, USA
| | - Zachary Goodall
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843, USA
| | - Laura McCleskey
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843, USA
| | - Rebecca Sechrist
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843, USA
| | - Lanying Zeng
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843, USA
| | - Nicholas J Savill
- Institute of Immunology and Infection Research, University of Edinburgh, Edinburgh, EH9 3FL, UK
| | - Silvi Rouskin
- Department of Microbiology, Harvard Medical School, Boston, MA 02115, USA
| | - Achim Schnaufer
- Institute of Immunology and Infection Research, University of Edinburgh, Edinburgh, EH9 3FL, UK
| | - Suzanne M McDermott
- Center for Global Infectious Disease Research, Seattle Children's Research Institute, Seattle, WA 98109, USA
- Department of Pediatrics, University of Washington School of Medicine, Seattle, WA, USA
| | - Jorge Cruz-Reyes
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843, USA
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2
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Fields O, Hammond MJ, Xu X, O'Neill EC. Advances in euglenoid genomics: unravelling the fascinating biology of a complex clade. Trends Genet 2024:S0168-9525(24)00173-2. [PMID: 39147613 DOI: 10.1016/j.tig.2024.07.007] [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: 06/27/2024] [Revised: 07/23/2024] [Accepted: 07/23/2024] [Indexed: 08/17/2024]
Abstract
Euglenids have long been studied due to their unique physiology and versatile metabolism, providing underpinnings for much of our understanding of photosynthesis and biochemistry, and a growing opportunity in biotechnology. Until recently there has been a lack of genetic studies due to their large and complex genomes, but recently new technologies have begun to unveil their genetic capabilities. Whilst much research has focused on the model organism Euglena gracilis, other members of the euglenids have now started to receive due attention. Currently only poor nuclear genome assemblies of E. gracilis and Rhabdomonas costata are available, but there are many more plastid genome sequences and an increasing number of transcriptomes. As more assemblies become available, there are great opportunities to understand the fundamental biology of these organisms and to exploit them for biotechnology.
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Affiliation(s)
- Oskar Fields
- School of Chemistry, University of Nottingham, University Park, Nottingham, NG7 2RD, UK; Biodiscovery Institute, University of Nottingham, University Park, Nottingham, NG7 2RD, UK; These authors contributed equally
| | - Michael J Hammond
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, České Budějovice (Budweis), Czech Republic; Faculty of Science, University of South Bohemia, České Budějovice (Budweis), Czech Republic; These authors contributed equally
| | - Xiao Xu
- School of Chemistry, University of Nottingham, University Park, Nottingham, NG7 2RD, UK; Biodiscovery Institute, University of Nottingham, University Park, Nottingham, NG7 2RD, UK; These authors contributed equally
| | - Ellis C O'Neill
- School of Chemistry, University of Nottingham, University Park, Nottingham, NG7 2RD, UK; Biodiscovery Institute, University of Nottingham, University Park, Nottingham, NG7 2RD, UK.
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3
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von Känel C, Stettler P, Esposito C, Berger S, Amodeo S, Oeljeklaus S, Calderaro S, Durante IM, Rašková V, Warscheid B, Schneider A. Pam16 and Pam18 were repurposed during Trypanosoma brucei evolution to regulate the replication of mitochondrial DNA. PLoS Biol 2024; 22:e3002449. [PMID: 39146359 PMCID: PMC11349236 DOI: 10.1371/journal.pbio.3002449] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2023] [Revised: 08/27/2024] [Accepted: 07/23/2024] [Indexed: 08/17/2024] Open
Abstract
Protein import and genome replication are essential processes for mitochondrial biogenesis and propagation. The J-domain proteins Pam16 and Pam18 regulate the presequence translocase of the mitochondrial inner membrane. In the protozoan Trypanosoma brucei, their counterparts are TbPam16 and TbPam18, which are essential for the procyclic form (PCF) of the parasite, though not involved in mitochondrial protein import. Here, we show that during evolution, the 2 proteins have been repurposed to regulate the replication of maxicircles within the intricate kDNA network, the most complex mitochondrial genome known. TbPam18 and TbPam16 have inactive J-domains suggesting a function independent of heat shock proteins. However, their single transmembrane domain is essential for function. Pulldown of TbPam16 identifies a putative client protein, termed MaRF11, the depletion of which causes the selective loss of maxicircles, akin to the effects observed for TbPam18 and TbPam16. Moreover, depletion of the mitochondrial proteasome results in increased levels of MaRF11. Thus, we have discovered a protein complex comprising TbPam18, TbPam16, and MaRF11, that controls maxicircle replication. We propose a working model in which the matrix protein MaRF11 functions downstream of the 2 integral inner membrane proteins TbPam18 and TbPam16. Moreover, we suggest that the levels of MaRF11 are controlled by the mitochondrial proteasome.
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Affiliation(s)
- Corinne von Känel
- Department of Chemistry, Biochemistry and Pharmaceutical Sciences, University of Bern, Bern, Switzerland
| | - Philip Stettler
- Department of Chemistry, Biochemistry and Pharmaceutical Sciences, University of Bern, Bern, Switzerland
| | - Carmela Esposito
- Department of Chemistry, Biochemistry and Pharmaceutical Sciences, University of Bern, Bern, Switzerland
| | - Stephan Berger
- Department of Chemistry, Biochemistry and Pharmaceutical Sciences, University of Bern, Bern, Switzerland
| | - Simona Amodeo
- Department of Chemistry, Biochemistry and Pharmaceutical Sciences, University of Bern, Bern, Switzerland
| | - Silke Oeljeklaus
- Faculty of Chemistry and Pharmacy, Biochemistry II, Theodor Boveri-Institute, University of Würzburg, Würzburg, Germany
| | - Salvatore Calderaro
- Department of Chemistry, Biochemistry and Pharmaceutical Sciences, University of Bern, Bern, Switzerland
| | - Ignacio M. Durante
- Institute of Parasitology, Biology Centre, České Budějovice, Czech Republic
| | - Vendula Rašková
- Institute of Parasitology, Biology Centre, České Budějovice, Czech Republic
- Faculty of Science, University of South Bohemia, České Budějovice, Czech Republic
| | - Bettina Warscheid
- Faculty of Chemistry and Pharmacy, Biochemistry II, Theodor Boveri-Institute, University of Würzburg, Würzburg, Germany
| | - André Schneider
- Department of Chemistry, Biochemistry and Pharmaceutical Sciences, University of Bern, Bern, Switzerland
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4
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Zamani H, Poorinmohammad N, Azimi A, Salavati R. From a bimodal to a multi-stage view on trypanosomes' differential RNA editing. Trends Parasitol 2024; 40:372-377. [PMID: 38494388 DOI: 10.1016/j.pt.2024.02.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2024] [Revised: 02/13/2024] [Accepted: 02/22/2024] [Indexed: 03/19/2024]
Abstract
Significant variations in the abundance of mitochondrial RNA processing proteins and their target RNAs across trypanosome life stages present an opportunity to explore the regulatory mechanisms that drive these changes. Utilizing omics approaches can uncover unconventional targets, aiding our understanding of the parasites' adaptation and enabling targeted interventions for differentiation.
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Affiliation(s)
- Homa Zamani
- Institute of Parasitology, McGill University, Ste. Anne de Bellevue, Quebec H9X 3V9, Canada
| | - Naghmeh Poorinmohammad
- Institute of Parasitology, McGill University, Ste. Anne de Bellevue, Quebec H9X 3V9, Canada
| | - Amin Azimi
- Institute of Parasitology, McGill University, Ste. Anne de Bellevue, Quebec H9X 3V9, Canada
| | - Reza Salavati
- Institute of Parasitology, McGill University, Ste. Anne de Bellevue, Quebec H9X 3V9, Canada; Department of Biochemistry, McGill University, Montreal, Quebec H3G 1Y6, Canada.
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5
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Afonin DA, Gerasimov ES, Škodová-Sveráková I, Záhonová K, Gahura O, Albanaz ATS, Myšková E, Bykova A, Paris Z, Lukeš J, Opperdoes FR, Horváth A, Zimmer SL, Yurchenko V. Blastocrithidia nonstop mitochondrial genome and its expression are remarkably insulated from nuclear codon reassignment. Nucleic Acids Res 2024; 52:3870-3885. [PMID: 38452217 DOI: 10.1093/nar/gkae168] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2023] [Revised: 02/20/2024] [Accepted: 02/27/2024] [Indexed: 03/09/2024] Open
Abstract
The canonical stop codons of the nuclear genome of the trypanosomatid Blastocrithidia nonstop are recoded. Here, we investigated the effect of this recoding on the mitochondrial genome and gene expression. Trypanosomatids possess a single mitochondrion and protein-coding transcripts of this genome require RNA editing in order to generate open reading frames of many transcripts encoded as 'cryptogenes'. Small RNAs that can number in the hundreds direct editing and produce a mitochondrial transcriptome of unusual complexity. We find B. nonstop to have a typical trypanosomatid mitochondrial genetic code, which presumably requires the mitochondrion to disable utilization of the two nucleus-encoded suppressor tRNAs, which appear to be imported into the organelle. Alterations of the protein factors responsible for mRNA editing were also documented, but they have likely originated from sources other than B. nonstop nuclear genome recoding. The population of guide RNAs directing editing is minimal, yet virtually all genes for the plethora of known editing factors are still present. Most intriguingly, despite lacking complex I cryptogene guide RNAs, these cryptogene transcripts are stochastically edited to high levels.
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MESH Headings
- Genome, Mitochondrial
- RNA Editing
- Cell Nucleus/genetics
- Cell Nucleus/metabolism
- RNA, Transfer/genetics
- RNA, Transfer/metabolism
- Open Reading Frames/genetics
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
- Trypanosomatina/genetics
- Trypanosomatina/metabolism
- Codon/genetics
- Mitochondria/genetics
- Mitochondria/metabolism
- Codon, Terminator/genetics
- RNA, Guide, Kinetoplastida/genetics
- RNA, Guide, Kinetoplastida/metabolism
- Genetic Code
- Protozoan Proteins/genetics
- Protozoan Proteins/metabolism
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Affiliation(s)
- Dmitry A Afonin
- Faculty of Biology, Lomonosov Moscow State University, Moscow 119991, Russia
| | - Evgeny S Gerasimov
- Faculty of Biology, Lomonosov Moscow State University, Moscow 119991, Russia
- Institute for Information Transmission Problems, Russian Academy of Sciences, Moscow 127051, Russia
| | - Ingrid Škodová-Sveráková
- Life Science Research Centre, Faculty of Science, University of Ostrava, 710 00 Ostrava, Czechia
- Department of Biochemistry, Faculty of Natural Sciences, Comenius University, 842 15 Bratislava, Slovakia
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, 370 05 České Budějovice, Czechia
| | - Kristína Záhonová
- Life Science Research Centre, Faculty of Science, University of Ostrava, 710 00 Ostrava, Czechia
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, 370 05 České Budějovice, Czechia
- Department of Parasitology, Faculty of Science, Charles University, BIOCEV 252 50 Vestec, Czechia
- Division of Infectious Diseases, Department of Medicine, University of Alberta, T6G 2R3 Edmonton, Alberta, Canada
| | - Ondřej Gahura
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, 370 05 České Budějovice, Czechia
| | - Amanda T S Albanaz
- Life Science Research Centre, Faculty of Science, University of Ostrava, 710 00 Ostrava, Czechia
| | - Eva Myšková
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, 370 05 České Budějovice, Czechia
| | - Anastassia Bykova
- Life Science Research Centre, Faculty of Science, University of Ostrava, 710 00 Ostrava, Czechia
| | - Zdeněk Paris
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, 370 05 České Budějovice, Czechia
- Faculty of Science, University of South Bohemia, 370 05 České Budějovice, Czechia
| | - Julius Lukeš
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, 370 05 České Budějovice, Czechia
- Faculty of Science, University of South Bohemia, 370 05 České Budějovice, Czechia
| | - Fred R Opperdoes
- De Duve Institute, Université Catholique de Louvain, 1200 Brussels, Belgium
| | - Anton Horváth
- Department of Biochemistry, Faculty of Natural Sciences, Comenius University, 842 15 Bratislava, Slovakia
| | - Sara L Zimmer
- University of Minnesota Medical School, Duluth Campus, Duluth, MN 55812, USA
| | - Vyacheslav Yurchenko
- Life Science Research Centre, Faculty of Science, University of Ostrava, 710 00 Ostrava, Czechia
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McDermott SM, Pham V, Oliver B, Carnes J, Sather DN, Stuart KD. Deep mutational scanning of the RNase III-like domain in Trypanosoma brucei RNA editing protein KREPB4. Front Cell Infect Microbiol 2024; 14:1381155. [PMID: 38650737 PMCID: PMC11033214 DOI: 10.3389/fcimb.2024.1381155] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2024] [Accepted: 03/14/2024] [Indexed: 04/25/2024] Open
Abstract
Kinetoplastid pathogens including Trypanosoma brucei, T. cruzi, and Leishmania species, are early diverged, eukaryotic, unicellular parasites. Functional understanding of many proteins from these pathogens has been hampered by limited sequence homology to proteins from other model organisms. Here we describe the development of a high-throughput deep mutational scanning approach in T. brucei that facilitates rapid and unbiased assessment of the impacts of many possible amino acid substitutions within a protein on cell fitness, as measured by relative cell growth. The approach leverages several molecular technologies: cells with conditional expression of a wild-type gene of interest and constitutive expression of a library of mutant variants, degron-controlled stabilization of I-SceI meganuclease to mediate highly efficient transfection of a mutant allele library, and a high-throughput sequencing readout for cell growth upon conditional knockdown of wild-type gene expression and exclusive expression of mutant variants. Using this method, we queried the effects of amino acid substitutions in the apparently non-catalytic RNase III-like domain of KREPB4 (B4), which is an essential component of the RNA Editing Catalytic Complexes (RECCs) that carry out mitochondrial RNA editing in T. brucei. We measured the impacts of thousands of B4 variants on bloodstream form cell growth and validated the most deleterious variants containing single amino acid substitutions. Crucially, there was no correlation between phenotypes and amino acid conservation, demonstrating the greater power of this method over traditional sequence homology searching to identify functional residues. The bloodstream form cell growth phenotypes were combined with structural modeling, RECC protein proximity data, and analysis of selected substitutions in procyclic form T. brucei. These analyses revealed that the B4 RNaseIII-like domain is essential for maintenance of RECC integrity and RECC protein abundances and is also involved in changes in RECCs that occur between bloodstream and procyclic form life cycle stages.
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Affiliation(s)
- Suzanne M. McDermott
- Center for Global Infectious Disease Research, Seattle Children’s Research Institute, Seattle, WA, United States
- Department of Pediatrics, University of Washington School of Medicine, Seattle, WA, United States
| | - Vy Pham
- Center for Global Infectious Disease Research, Seattle Children’s Research Institute, Seattle, WA, United States
| | - Brian Oliver
- Center for Global Infectious Disease Research, Seattle Children’s Research Institute, Seattle, WA, United States
| | - Jason Carnes
- Center for Global Infectious Disease Research, Seattle Children’s Research Institute, Seattle, WA, United States
| | - D. Noah Sather
- Center for Global Infectious Disease Research, Seattle Children’s Research Institute, Seattle, WA, United States
- Department of Pediatrics, University of Washington School of Medicine, Seattle, WA, United States
| | - Kenneth D. Stuart
- Center for Global Infectious Disease Research, Seattle Children’s Research Institute, Seattle, WA, United States
- Department of Pediatrics, University of Washington School of Medicine, Seattle, WA, United States
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7
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Poorinmohammad N, Salavati R. Prioritization of Trypanosoma brucei editosome protein interactions interfaces at residue resolution through proteome-scale network analysis. BMC Mol Cell Biol 2024; 25:3. [PMID: 38279116 PMCID: PMC10811811 DOI: 10.1186/s12860-024-00499-4] [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: 09/26/2023] [Accepted: 01/19/2024] [Indexed: 01/28/2024] Open
Abstract
BACKGROUND Trypanosoma brucei is the causative agent for trypanosomiasis in humans and livestock, which presents a growing challenge due to drug resistance. While identifying novel drug targets is vital, the process is delayed due to a lack of functional information on many of the pathogen's proteins. Accordingly, this paper presents a computational framework for prioritizing drug targets within the editosome, a vital molecular machinery responsible for mitochondrial RNA processing in T. brucei. Importantly, this framework may eliminate the need for prior gene or protein characterization, potentially accelerating drug discovery efforts. RESULTS By integrating protein-protein interaction (PPI) network analysis, PPI structural modeling, and residue interaction network (RIN) analysis, we quantitatively ranked and identified top hub editosome proteins, their key interaction interfaces, and hotspot residues. Our findings were cross-validated and further prioritized by incorporating them into gene set analysis and differential expression analysis of existing quantitative proteomics data across various life stages of T. brucei. In doing so, we highlighted PPIs such as KREL2-KREPA1, RESC2-RESC1, RESC12A-RESC13, and RESC10-RESC6 as top candidates for further investigation. This includes examining their interfaces and hotspot residues, which could guide drug candidate selection and functional studies. CONCLUSION RNA editing offers promise for target-based drug discovery, particularly with proteins and interfaces that play central roles in the pathogen's life cycle. This study introduces an integrative drug target identification workflow combining information from the PPI network, PPI 3D structure, and reside-level information of their interface which can be applicable to diverse pathogens. In the case of T. brucei, via this pipeline, the present study suggested potential drug targets with residue-resolution from RNA editing machinery. However, experimental validation is needed to fully realize its potential in advancing urgently needed antiparasitic drug development.
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Affiliation(s)
- Naghmeh Poorinmohammad
- Institute of Parasitology, McGill University, Ste. Anne de Bellevue, Montreal, Quebec, H9X 3V9, Canada
| | - Reza Salavati
- Institute of Parasitology, McGill University, Ste. Anne de Bellevue, Montreal, Quebec, H9X 3V9, Canada.
- Department of Biochemistry, McGill University, Montreal, Quebec, H3G 1Y6, Canada.
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8
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Rostamighadi M, Kamelshahroudi A, Mehta V, Zeng FY, Pass I, Chung TDY, Salavati R. High-throughput screening of compounds targeting RNA editing in Trypanosoma brucei: Novel molecular scaffolds with broad trypanocidal effects. Biochem Pharmacol 2024; 219:115937. [PMID: 37995979 DOI: 10.1016/j.bcp.2023.115937] [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: 09/11/2023] [Revised: 11/15/2023] [Accepted: 11/16/2023] [Indexed: 11/25/2023]
Abstract
Mitochondrial uridine insertion/deletion RNA editing, catalyzed by a multiprotein complex (editosome), is essential for gene expression in trypanosomes and Leishmania parasites. As this process is absent in the human host, a drug targeting this mechanism promises high selectivity and reduced toxicity. Here, we successfully miniaturized our FRET-based full-round RNA editing assay, which replicates the complete RNA editing process, adapting it into a 1536-well format. Leveraging this assay, we screened over 100,000 compounds against purified editosomes derived from Trypanosoma brucei, identifying seven confirmed primary hits. We sourced and evaluated various analogs to enhance the inhibitory and parasiticidal effects of these primary hits. In combination with secondary assays, our compounds marked inhibition of essential catalytic activities, including the RNA editing ligase and interactions of editosome proteins. Although the primary hits did not exhibit any growth inhibitory effect on parasites, we describe eight analog compounds capable of effectively killing T. brucei and/or Leishmania donovani parasites within a low micromolar concentration. Whether parasite killing is - at least in part - due to inhibition of RNA editing in vivo remains to be assessed. Our findings introduce novel molecular scaffolds with the potential for broad antitrypanosomal effects.
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Affiliation(s)
- Mojtaba Rostamighadi
- Institute of Parasitology, McGill University, Ste. Anne de Bellevue, Quebec H9X 3V9, Canada
| | - Arezou Kamelshahroudi
- Institute of Parasitology, McGill University, Ste. Anne de Bellevue, Quebec H9X 3V9, Canada
| | - Vaibhav Mehta
- Institute of Parasitology, McGill University, Ste. Anne de Bellevue, Quebec H9X 3V9, Canada; Department of Biochemistry, McGill University, Montreal, Quebec H3G 1Y6, Canada
| | - Fu-Yue Zeng
- Sanford Burnham Prebys Medical Discovery Institute, Conrad Prebys Center for Chemical Genomics, La Jolla, CA, USA
| | - Ian Pass
- Sanford Burnham Prebys Medical Discovery Institute, Conrad Prebys Center for Chemical Genomics, La Jolla, CA, USA
| | - Thomas D Y Chung
- Sanford Burnham Prebys Medical Discovery Institute, Conrad Prebys Center for Chemical Genomics, La Jolla, CA, USA
| | - Reza Salavati
- Institute of Parasitology, McGill University, Ste. Anne de Bellevue, Quebec H9X 3V9, Canada; Department of Biochemistry, McGill University, Montreal, Quebec H3G 1Y6, Canada.
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9
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Carnes J, McDermott SM, Stuart K. RNA editing catalytic complexes edit multiple mRNA sites non-processively in Trypanosoma brucei. Mol Biochem Parasitol 2023; 256:111596. [PMID: 37742784 DOI: 10.1016/j.molbiopara.2023.111596] [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: 06/27/2023] [Revised: 08/25/2023] [Accepted: 09/20/2023] [Indexed: 09/26/2023]
Abstract
RNA editing generates mature mitochondrial mRNAs in T. brucei by extensive uridine insertion and deletion at numerous editing sites (ESs) as specified by guide RNAs (gRNAs). The editing is performed by three RNA Editing Catalytic Complexes (RECCs) which each have a different endonuclease in addition to 12 proteins in common resulting in RECC1 that is specific for deletion ESs and RECC2 and RECC3 that are specific for insertion ESs. Thus, different RECCs are required for editing of mRNA sequence regions where single gRNAs specify a combination of insertion and deletion ESs. We investigated how the three different RECCs might edit combinations of insertion and deletion ESs that are specified by single gRNAs by testing whether their endonuclease compositions are stable or dynamic during editing. We analyzed in vivo BirA* proximity labeling and found that the endonucleases remain associated with their set of common RECC proteins during editing when expressed at normal physiological levels. We also found that overexpression of endonuclease components resulted in minor effects on RECCs but did not affect growth. Thus, the protein stoichiometries that exist within each RECC can be altered by perturbations of RECC expression levels. These results indicate that editing of consecutive insertion and deletion ESs occurs by successive engagement and disengagement of RECCs, i.e., is non-processive, which is likely the case for consecutive pairs of insertion or deletion ESs. This clarifies the nature of the complex patterns of partially edited mRNAs that occur in vivo.
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Affiliation(s)
- Jason Carnes
- Seattle Children's Research Institute, Seattle, WA 98109, USA
| | - Suzanne M McDermott
- Seattle Children's Research Institute, Seattle, WA 98109, USA; Departments of Pediatrics and Global Health, University of Washington, Seattle, WA 98195, USA
| | - Kenneth Stuart
- Seattle Children's Research Institute, Seattle, WA 98109, USA; Departments of Pediatrics and Global Health, University of Washington, Seattle, WA 98195, USA.
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10
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Aeschlimann S, Stettler P, Schneider A. DNA segregation in mitochondria and beyond: insights from the trypanosomal tripartite attachment complex. Trends Biochem Sci 2023; 48:1058-1070. [PMID: 37775421 DOI: 10.1016/j.tibs.2023.08.012] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2023] [Revised: 08/13/2023] [Accepted: 08/28/2023] [Indexed: 10/01/2023]
Abstract
The tripartite attachment complex (TAC) of the single mitochondrion of trypanosomes allows precise segregation of its single nucleoid mitochondrial genome during cytokinesis. It couples the segregation of the duplicated mitochondrial genome to the segregation of the basal bodies of the flagella. Here, we provide a model of the molecular architecture of the TAC that explains how its eight essential subunits connect the basal body, across the mitochondrial membranes, with the mitochondrial genome. We also discuss how the TAC subunits are imported into the mitochondrion and how they assemble to form a new TAC. Finally, we present a comparative analysis of the trypanosomal TAC with open and closed mitotic spindles, which reveals conserved concepts between these diverse DNA segregation systems.
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Affiliation(s)
- Salome Aeschlimann
- Department of Chemistry, Biochemistry, and Pharmaceutical Sciences, University of Bern, Freiestrasse 3, Bern CH-3012, Switzerland
| | - Philip Stettler
- Department of Chemistry, Biochemistry, and Pharmaceutical Sciences, University of Bern, Freiestrasse 3, Bern CH-3012, Switzerland; Graduate School for Cellular and Biomedical Sciences, University of Bern, Bern CH-3012, Switzerland
| | - André Schneider
- Department of Chemistry, Biochemistry, and Pharmaceutical Sciences, University of Bern, Freiestrasse 3, Bern CH-3012, Switzerland; Institute for Advanced Study (Wissenschaftskolleg) Berlin, D-14193 Berlin, Germany.
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11
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Rajan KS, Madmoni H, Bashan A, Taoka M, Aryal S, Nobe Y, Doniger T, Galili Kostin B, Blumberg A, Cohen-Chalamish S, Schwartz S, Rivalta A, Zimmerman E, Unger R, Isobe T, Yonath A, Michaeli S. A single pseudouridine on rRNA regulates ribosome structure and function in the mammalian parasite Trypanosoma brucei. Nat Commun 2023; 14:7462. [PMID: 37985661 PMCID: PMC10662448 DOI: 10.1038/s41467-023-43263-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2022] [Accepted: 11/05/2023] [Indexed: 11/22/2023] Open
Abstract
Trypanosomes are protozoan parasites that cycle between insect and mammalian hosts and are the causative agent of sleeping sickness. Here, we describe the changes of pseudouridine (Ψ) modification on rRNA in the two life stages of the parasite using four different genome-wide approaches. CRISPR-Cas9 knock-outs of all four snoRNAs guiding Ψ on helix 69 (H69) of the large rRNA subunit were lethal. A single knock-out of a snoRNA guiding Ψ530 on H69 altered the composition of the 80S monosome. These changes specifically affected the translation of only a subset of proteins. This study correlates a single site Ψ modification with changes in ribosomal protein stoichiometry, supported by a high-resolution cryo-EM structure. We propose that alteration in rRNA modifications could generate ribosomes preferentially translating state-beneficial proteins.
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Affiliation(s)
- K Shanmugha Rajan
- The Mina and Everard Goodman Faculty of Life Sciences and Advanced and Nanotechnology Institute, Bar-Ilan University, Ramat-Gan, 5290002, Israel
- Department of Chemical and Structural Biology, Weizmann Institute of Science, Rehovot, 7610001, Israel
| | - Hava Madmoni
- The Mina and Everard Goodman Faculty of Life Sciences and Advanced and Nanotechnology Institute, Bar-Ilan University, Ramat-Gan, 5290002, Israel
| | - Anat Bashan
- Department of Chemical and Structural Biology, Weizmann Institute of Science, Rehovot, 7610001, Israel
| | - Masato Taoka
- Department of Chemistry, Graduate School of Science, Tokyo Metropolitan University, Minami-osawa 1-1, Hachioji-shi, Tokyo, 192-0397, Japan
| | - Saurav Aryal
- The Mina and Everard Goodman Faculty of Life Sciences and Advanced and Nanotechnology Institute, Bar-Ilan University, Ramat-Gan, 5290002, Israel
| | - Yuko Nobe
- Department of Chemistry, Graduate School of Science, Tokyo Metropolitan University, Minami-osawa 1-1, Hachioji-shi, Tokyo, 192-0397, Japan
| | - Tirza Doniger
- The Mina and Everard Goodman Faculty of Life Sciences and Advanced and Nanotechnology Institute, Bar-Ilan University, Ramat-Gan, 5290002, Israel
| | - Beathrice Galili Kostin
- The Mina and Everard Goodman Faculty of Life Sciences and Advanced and Nanotechnology Institute, Bar-Ilan University, Ramat-Gan, 5290002, Israel
| | - Amit Blumberg
- Department of Chemistry, Graduate School of Science, Tokyo Metropolitan University, Minami-osawa 1-1, Hachioji-shi, Tokyo, 192-0397, Japan
| | - Smadar Cohen-Chalamish
- The Mina and Everard Goodman Faculty of Life Sciences and Advanced and Nanotechnology Institute, Bar-Ilan University, Ramat-Gan, 5290002, Israel
| | - Schraga Schwartz
- Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, 76100, Israel
| | - Andre Rivalta
- Department of Chemical and Structural Biology, Weizmann Institute of Science, Rehovot, 7610001, Israel
| | - Ella Zimmerman
- Department of Chemical and Structural Biology, Weizmann Institute of Science, Rehovot, 7610001, Israel
| | - Ron Unger
- The Mina and Everard Goodman Faculty of Life Sciences and Advanced and Nanotechnology Institute, Bar-Ilan University, Ramat-Gan, 5290002, Israel
| | - Toshiaki Isobe
- Department of Chemistry, Graduate School of Science, Tokyo Metropolitan University, Minami-osawa 1-1, Hachioji-shi, Tokyo, 192-0397, Japan
| | - Ada Yonath
- Department of Chemical and Structural Biology, Weizmann Institute of Science, Rehovot, 7610001, Israel
| | - Shulamit Michaeli
- The Mina and Everard Goodman Faculty of Life Sciences and Advanced and Nanotechnology Institute, Bar-Ilan University, Ramat-Gan, 5290002, Israel.
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12
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Lukeš J, Speijer D, Zíková A, Alfonzo JD, Hashimi H, Field MC. Trypanosomes as a magnifying glass for cell and molecular biology. Trends Parasitol 2023; 39:902-912. [PMID: 37679284 DOI: 10.1016/j.pt.2023.08.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Revised: 08/08/2023] [Accepted: 08/09/2023] [Indexed: 09/09/2023]
Abstract
The African trypanosome, Trypanosoma brucei, has developed into a flexible and robust experimental model for molecular and cellular parasitology, allowing us to better combat these and related parasites that cause worldwide suffering. Diminishing case numbers, due to efficient public health efforts, and recent development of new drug treatments have reduced the need for continued study of T. brucei in a disease context. However, we argue that this pathogen has been instrumental in revolutionary discoveries that have widely informed molecular and cellular biology and justifies continuing research as an experimental model. Ongoing work continues to contribute towards greater understanding of both diversified and conserved biological features. We discuss multiple examples where trypanosomes pushed the boundaries of cell biology and hope to inspire researchers to continue exploring these remarkable protists as tools for magnifying the inner workings of cells.
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Affiliation(s)
- Julius Lukeš
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, České Budějovice (Budweis), Czech Republic; Faculty of Sciences, University of South Bohemia, České Budějovice (Budweis), Czech Republic.
| | - Dave Speijer
- Medical Biochemistry, University of Amsterdam, AMC, Amsterdam, The Netherlands
| | - Alena Zíková
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, České Budějovice (Budweis), Czech Republic; Faculty of Sciences, University of South Bohemia, České Budějovice (Budweis), Czech Republic
| | - Juan D Alfonzo
- Department of Molecular Biology, Cell Biology and Biochemistry, Brown University, Providence, RI, USA
| | - Hassan Hashimi
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, České Budějovice (Budweis), Czech Republic; Faculty of Sciences, University of South Bohemia, České Budějovice (Budweis), Czech Republic
| | - Mark C Field
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, České Budějovice (Budweis), Czech Republic; School of Life Sciences, University of Dundee, Dundee, UK
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13
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Smith JT, Tylec B, Naguleswaran A, Roditi I, Read LK. Developmental dynamics of mitochondrial mRNA abundance and editing reveal roles for temperature and the differentiation-repressive kinase RDK1 in cytochrome oxidase subunit II mRNA editing. mBio 2023; 14:e0185423. [PMID: 37795988 PMCID: PMC10653865 DOI: 10.1128/mbio.01854-23] [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: 07/13/2023] [Accepted: 08/15/2023] [Indexed: 10/06/2023] Open
Abstract
IMPORTANCE Trypanosoma brucei is the unicellular parasite that causes African sleeping sickness and nagana disease in livestock. The parasite has a complex life cycle consisting of several developmental forms in the human and tsetse fly insect vector. Both the mammalian and insect hosts provide different nutritional environments, so T. brucei must adapt its metabolism to promote its survival and to complete its life cycle. As T. brucei is transmitted from the human host to the fly, the parasite must regulate its mitochondrial gene expression through a process called uridine insertion/deletion editing to achieve mRNAs capable of being translated into functional respiratory chain proteins required for energy production in the insect host. Therefore, it is essential to understand the mechanisms by which T. brucei regulates mitochondrial gene expression during transmission from the mammalian host to the insect vector.
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Affiliation(s)
- Joseph T. Smith
- Department of Microbiology and Immunology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, New York, USA
| | - Brianna Tylec
- Department of Microbiology and Immunology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, New York, USA
| | | | - Isabel Roditi
- Institute of Cell Biology, University of Bern, Bern, Switzerland
| | - Laurie K. Read
- Department of Microbiology and Immunology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, New York, USA
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14
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Davidge B, McDermott SM, Carnes J, Lewis I, Tracy M, Stuart KD. Multiple domains of the integral KREPA3 protein are critical for the structure and precise functions of RNA editing catalytic complexes in Trypanosoma brucei. RNA (NEW YORK, N.Y.) 2023; 29:1591-1609. [PMID: 37474258 PMCID: PMC10578492 DOI: 10.1261/rna.079691.123] [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: 04/19/2023] [Accepted: 06/30/2023] [Indexed: 07/22/2023]
Abstract
The gRNA directed U-insertion and deletion editing of mitochondrial mRNAs that is essential in different life-cycle stages for the protozoan parasite Trypanosoma brucei is performed by three similar multiprotein catalytic complexes (CCs) that contain the requisite enzymes. These CCs also contain a common set of eight proteins that have no apparent direct catalytic function, including six that have an OB-fold domain. We show here that one of these OB-fold proteins, KREPA3 (A3), has structural homology to other editing proteins, is essential for editing, and is multifunctional. We investigated A3 function by analyzing the effects of single amino acid loss of function mutations, most of which were identified by screening bloodstream form (BF) parasites for loss of growth following random mutagenesis. Mutations in the zinc fingers (ZFs), an intrinsically disordered region (IDR), and several within or near the carboxy-terminal OB-fold domain variably impacted CC structural integrity and editing. Some mutations resulted in almost complete loss of CCs and its proteins and editing, whereas others retained CCs but had aberrant editing. All but a mutation which is near the OB-fold affected growth and editing in BF but not procyclic form (PF) parasites. These data indicate that multiple positions within A3 have essential functions that contribute to the structural integrity of CCs, the precision of editing and the developmental differences in editing between BF and PF stages.
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Affiliation(s)
- Brittney Davidge
- Center for Global Infectious Disease Research (CGIDR), Seattle Children's Research Institute, Seattle, Washington 98109, USA
| | - Suzanne M McDermott
- Center for Global Infectious Disease Research (CGIDR), Seattle Children's Research Institute, Seattle, Washington 98109, USA
- Department of Pediatrics, University of Washington, Seattle, Washington 98195, USA
| | - Jason Carnes
- Center for Global Infectious Disease Research (CGIDR), Seattle Children's Research Institute, Seattle, Washington 98109, USA
| | - Isaac Lewis
- Center for Global Infectious Disease Research (CGIDR), Seattle Children's Research Institute, Seattle, Washington 98109, USA
| | - Maxwell Tracy
- Center for Global Infectious Disease Research (CGIDR), Seattle Children's Research Institute, Seattle, Washington 98109, USA
| | - Kenneth D Stuart
- Center for Global Infectious Disease Research (CGIDR), Seattle Children's Research Institute, Seattle, Washington 98109, USA
- Department of Pediatrics, University of Washington, Seattle, Washington 98195, USA
- Department of Global Health, University of Washington, Seattle, Washington 98195, USA
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15
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McDermott SM, Pham V, Lewis I, Tracy M, Stuart K. mt-LAF3 is a pseudouridine synthase ortholog required for mitochondrial rRNA and mRNA gene expression in Trypanosoma brucei. Int J Parasitol 2023; 53:573-583. [PMID: 37268169 PMCID: PMC10527287 DOI: 10.1016/j.ijpara.2023.04.002] [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: 02/23/2023] [Revised: 04/05/2023] [Accepted: 04/11/2023] [Indexed: 06/04/2023]
Abstract
Trypanosoma brucei and related kinetoplastid parasites possess unique RNA processing pathways, including in their mitochondria, that regulate metabolism and development. Altering RNA composition or conformation through nucleotide modifications is one such pathway, and modifications including pseudouridine regulate RNA fate and function in many organisms. We surveyed pseudouridine synthase (PUS) orthologs in trypanosomatids, with a particular interest in mitochondrial enzymes due to their potential importance for mitochondrial function and metabolism. Trypanosoma brucei mitochondrial (mt)-LAF3 is an ortholog of human and yeast mitochondrial PUS enzymes, and a mitoribosome assembly factor, but structural studies differ in their conclusion as to whether it has PUS catalytic activity. Here, we generated T. brucei cells that are conditionally null (CN) for mt-LAF3 expression and showed that mt-LAF3 loss is lethal and disrupts mitochondrial membrane potential (ΔΨm). Addition of a mutant gamma ATP synthase allele to the CN cells permitted ΔΨm maintenance and cell survival, allowing us to assess primary effects on mitochondrial RNAs. As expected, these studies showed that loss of mt-LAF3 dramatically decreases levels of mitochondrial 12S and 9S rRNAs. Notably, we also observed decreases in mitochondrial mRNA levels, including differential effects on edited vs. pre-edited mRNAs, indicating that mt-LAF3 is required for mitochondrial rRNA and mRNA processing, including of edited transcripts. To assess the importance of PUS catalytic activity in mt-LAF3 we mutated a conserved aspartate that is necessary for catalysis in other PUS enzymes and showed it is not essential for cell growth, or maintenance of ΔΨm and mitochondrial RNA levels. Together, these results indicate that mt-LAF3 is required for normal expression of mitochondrial mRNAs in addition to rRNAs, but that PUS catalytic activity is not required for these functions. Instead, our work, combined with previous structural studies, suggests that T. brucei mt-LAF3 acts as a mitochondrial RNA-stabilizing scaffold.
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Affiliation(s)
- Suzanne M McDermott
- Seattle Children's Research Institute, Seattle, WA, USA; Department of Pediatrics, University of Washington School of Medicine, Seattle, WA, USA.
| | - Vy Pham
- Seattle Children's Research Institute, Seattle, WA, USA
| | - Isaac Lewis
- Seattle Children's Research Institute, Seattle, WA, USA
| | - Maxwell Tracy
- Seattle Children's Research Institute, Seattle, WA, USA
| | - Kenneth Stuart
- Seattle Children's Research Institute, Seattle, WA, USA; Department of Pediatrics, University of Washington School of Medicine, Seattle, WA, USA.
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16
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Gerasimov ES, Novozhilova TS, Zimmer SL, Yurchenko V. Kinetoplast Genome of Leishmania spp. Is under Strong Purifying Selection. Trop Med Infect Dis 2023; 8:384. [PMID: 37624322 PMCID: PMC10458658 DOI: 10.3390/tropicalmed8080384] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2023] [Revised: 07/24/2023] [Accepted: 07/25/2023] [Indexed: 08/26/2023] Open
Abstract
Instability is an intriguing characteristic of many protist genomes, and trypanosomatids are not an exception in this respect. Some regions of trypanosomatid genomes evolve fast. For instance, the trypanosomatid mitochondrial (kinetoplast) genome consists of fairly conserved maxicircle and minicircle molecules that can, nevertheless, possess high nucleotide substitution rates between closely related strains. Recent experiments have demonstrated that rapid laboratory evolution can result in the non-functionality of multiple genes of kinetoplast genomes due to the accumulation of mutations or loss of critical genomic components. An example of a loss of critical components is the reported loss of entire minicircle classes in Leishmania tarentolae during laboratory cultivation, which results in an inability to generate some correctly encoded genes. In the current work, we estimated the evolutionary rates of mitochondrial and nuclear genome regions of multiple natural Leishmania spp. We analyzed synonymous and non-synonymous substitutions and, rather unexpectedly, found that the coding regions of kinetoplast maxicircles are among the most variable regions of both genomes. In addition, we demonstrate that synonymous substitutions greatly predominate among maxicircle coding regions and that most maxicircle genes show signs of purifying selection. These results imply that maxicircles in natural Leishmania populations remain functional despite their high mutation rate.
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Affiliation(s)
- Evgeny S. Gerasimov
- Department of Molecular Biology, Lomonosov Moscow State University, 119234 Moscow, Russia
- Institute for Information Transmission Problems, Russian Academy of Sciences, 127051 Moscow, Russia
| | - Tatiana S. Novozhilova
- Department of Molecular Biology, Lomonosov Moscow State University, 119234 Moscow, Russia
| | - Sara L. Zimmer
- Department of Biomedical Sciences, University of Minnesota Medical School, Duluth Campus, Duluth, MN 55812, USA
| | - Vyacheslav Yurchenko
- Life Science Research Centre, Faculty of Science, University of Ostrava, 710 00 Ostrava, Czech Republic
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17
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Liu S, Wang H, Li X, Zhang F, Lee JKJ, Li Z, Yu C, Hu JJ, Zhao X, Suematsu T, Alvarez-Cabrera AL, Liu Q, Zhang L, Huang L, Aphasizheva I, Aphasizhev R, Zhou ZH. Structural basis of gRNA stabilization and mRNA recognition in trypanosomal RNA editing. Science 2023; 381:eadg4725. [PMID: 37410820 DOI: 10.1126/science.adg4725] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2022] [Accepted: 05/17/2023] [Indexed: 07/08/2023]
Abstract
In Trypanosoma brucei, the editosome, composed of RNA-editing substrate-binding complex (RESC) and RNA-editing catalytic complex (RECC), orchestrates guide RNA (gRNA)-programmed editing to recode cryptic mitochondrial transcripts into messenger RNAs (mRNAs). The mechanism of information transfer from gRNA to mRNA is unclear owing to a lack of high-resolution structures for these complexes. With cryo-electron microscopy and functional studies, we have captured gRNA-stabilizing RESC-A and gRNA-mRNA-binding RESC-B and RESC-C particles. RESC-A sequesters gRNA termini, thus promoting hairpin formation and blocking mRNA access. The conversion of RESC-A into RESC-B or -C unfolds gRNA and allows mRNA selection. The ensuing gRNA-mRNA duplex protrudes from RESC-B, likely exposing editing sites to RECC-catalyzed cleavage, uridine insertion or deletion, and ligation. Our work reveals a remodeling event facilitating gRNA-mRNA hybridization and assembly of a macromolecular substrate for the editosome's catalytic modality.
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Affiliation(s)
- Shiheng Liu
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, CA, USA
- California NanoSystems Institute, University of California, Los Angeles, CA, USA
| | - Hong Wang
- Department of Molecular and Cell Biology, Boston University Medical Campus, Boston, MA, USA
| | - Xiaorun Li
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, CA, USA
- California NanoSystems Institute, University of California, Los Angeles, CA, USA
| | - Fan Zhang
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China
| | - Jane K J Lee
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, CA, USA
- California NanoSystems Institute, University of California, Los Angeles, CA, USA
| | - Zihang Li
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, CA, USA
- California NanoSystems Institute, University of California, Los Angeles, CA, USA
| | - Clinton Yu
- Department of Physiology and Biophysics, University of California, Irvine, CA, USA
| | - Jason J Hu
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, CA, USA
- California NanoSystems Institute, University of California, Los Angeles, CA, USA
| | - Xiaojing Zhao
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China
| | - Takuma Suematsu
- Department of Molecular and Cell Biology, Boston University Medical Campus, Boston, MA, USA
| | - Ana L Alvarez-Cabrera
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, CA, USA
- California NanoSystems Institute, University of California, Los Angeles, CA, USA
| | - Qiushi Liu
- Department of Molecular and Cell Biology, Boston University Medical Campus, Boston, MA, USA
| | - Liye Zhang
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China
- Shanghai Clinical Research and Trial Center, Shanghai 201210, China
| | - Lan Huang
- Department of Physiology and Biophysics, University of California, Irvine, CA, USA
| | - Inna Aphasizheva
- Department of Molecular and Cell Biology, Boston University Medical Campus, Boston, MA, USA
| | - Ruslan Aphasizhev
- Department of Molecular and Cell Biology, Boston University Medical Campus, Boston, MA, USA
- Department of Biochemistry, Boston University Medical Campus, Boston, MA, USA
| | - Z Hong Zhou
- Department of Microbiology, Immunology, and Molecular Genetics, University of California, Los Angeles, CA, USA
- California NanoSystems Institute, University of California, Los Angeles, CA, USA
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18
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Nascimento JF, Souza ROO, Alencar MB, Marsiccobetre S, Murillo AM, Damasceno FS, Girard RBMM, Marchese L, Luévano-Martinez LA, Achjian RW, Haanstra JR, Michels PAM, Silber AM. How much (ATP) does it cost to build a trypanosome? A theoretical study on the quantity of ATP needed to maintain and duplicate a bloodstream-form Trypanosoma brucei cell. PLoS Pathog 2023; 19:e1011522. [PMID: 37498954 PMCID: PMC10409291 DOI: 10.1371/journal.ppat.1011522] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2023] [Revised: 08/08/2023] [Accepted: 06/29/2023] [Indexed: 07/29/2023] Open
Abstract
ATP hydrolysis is required for the synthesis, transport and polymerization of monomers for macromolecules as well as for the assembly of the latter into cellular structures. Other cellular processes not directly related to synthesis of biomass, such as maintenance of membrane potential and cellular shape, also require ATP. The unicellular flagellated parasite Trypanosoma brucei has a complex digenetic life cycle. The primary energy source for this parasite in its bloodstream form (BSF) is glucose, which is abundant in the host's bloodstream. Here, we made a detailed estimation of the energy budget during the BSF cell cycle. As glycolysis is the source of most produced ATP, we calculated that a single parasite produces 6.0 x 1011 molecules of ATP/cell cycle. Total biomass production (which involves biomass maintenance and duplication) accounts for ~63% of the total energy budget, while the total biomass duplication accounts for the remaining ~37% of the ATP consumption, with in both cases translation being the most expensive process. These values allowed us to estimate a theoretical YATP of 10.1 (g biomass)/mole ATP and a theoretical [Formula: see text] of 28.6 (g biomass)/mole ATP. Flagellar motility, variant surface glycoprotein recycling, transport and maintenance of transmembrane potential account for less than 30% of the consumed ATP. Finally, there is still ~5.5% available in the budget that is being used for other cellular processes of as yet unknown cost. These data put a new perspective on the assumptions about the relative energetic weight of the processes a BSF trypanosome undergoes during its cell cycle.
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Affiliation(s)
- Janaina F. Nascimento
- Laboratory of Biochemistry of Tryps–LaBTryps, Department of Parasitology, Institute of Biomedical Sciences, University of São Paulo–São Paulo, Brazil
| | - Rodolpho O. O. Souza
- Laboratory of Biochemistry of Tryps–LaBTryps, Department of Parasitology, Institute of Biomedical Sciences, University of São Paulo–São Paulo, Brazil
| | - Mayke B. Alencar
- Laboratory of Biochemistry of Tryps–LaBTryps, Department of Parasitology, Institute of Biomedical Sciences, University of São Paulo–São Paulo, Brazil
| | - Sabrina Marsiccobetre
- Laboratory of Biochemistry of Tryps–LaBTryps, Department of Parasitology, Institute of Biomedical Sciences, University of São Paulo–São Paulo, Brazil
| | - Ana M. Murillo
- Laboratory of Biochemistry of Tryps–LaBTryps, Department of Parasitology, Institute of Biomedical Sciences, University of São Paulo–São Paulo, Brazil
| | - Flávia S. Damasceno
- Laboratory of Biochemistry of Tryps–LaBTryps, Department of Parasitology, Institute of Biomedical Sciences, University of São Paulo–São Paulo, Brazil
| | - Richard B. M. M. Girard
- Laboratory of Biochemistry of Tryps–LaBTryps, Department of Parasitology, Institute of Biomedical Sciences, University of São Paulo–São Paulo, Brazil
| | - Letícia Marchese
- Laboratory of Biochemistry of Tryps–LaBTryps, Department of Parasitology, Institute of Biomedical Sciences, University of São Paulo–São Paulo, Brazil
| | - Luis A. Luévano-Martinez
- Laboratory of Biochemistry of Tryps–LaBTryps, Department of Parasitology, Institute of Biomedical Sciences, University of São Paulo–São Paulo, Brazil
| | - Renan W. Achjian
- Laboratory of Biochemistry of Tryps–LaBTryps, Department of Parasitology, Institute of Biomedical Sciences, University of São Paulo–São Paulo, Brazil
| | - Jurgen R. Haanstra
- Systems Biology Lab, Amsterdam Institute of Molecular and Life Sciences (AIMMS), Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Paul A. M. Michels
- School of Biological Sciences, The University of Edinburgh, Edinburgh, United Kingdom
| | - Ariel M. Silber
- Laboratory of Biochemistry of Tryps–LaBTryps, Department of Parasitology, Institute of Biomedical Sciences, University of São Paulo–São Paulo, Brazil
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19
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Amodeo S, Bregy I, Hoffmann A, Fradera-Sola A, Kern M, Baudouin H, Zuber B, Butter F, Ochsenreiter T. Characterization of two novel proteins involved in mitochondrial DNA anchoring in Trypanosoma brucei. PLoS Pathog 2023; 19:e1011486. [PMID: 37459364 PMCID: PMC10374059 DOI: 10.1371/journal.ppat.1011486] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2022] [Revised: 07/27/2023] [Accepted: 06/14/2023] [Indexed: 07/28/2023] Open
Abstract
Trypanosoma brucei is a single celled eukaryotic parasite in the group of the Kinetoplastea. The parasite harbors a single mitochondrion with a singular mitochondrial genome that is known as the kinetoplast DNA (kDNA). The kDNA consists of a unique network of thousands of interlocked circular DNA molecules. To ensure proper inheritance of the kDNA to the daughter cells, the genome is physically linked to the basal body, the master organizer of the cell cycle in trypanosomes. The connection that spans, cytoplasm, mitochondrial membranes and the mitochondrial matrix is mediated by the Tripartite Attachment Complex (TAC). Using a combination of proteomics and RNAi we test the current model of hierarchical TAC assembly and identify TbmtHMG44 and TbKAP68 as novel candidates of a complex that connects the TAC to the kDNA. Depletion of TbmtHMG44 or TbKAP68 each leads to a strong kDNA loss but not missegregation phenotype as previously defined for TAC components. We demonstrate that the proteins rely on both the TAC and the kDNA for stable localization to the interface between these two structures. In vitro experiments suggest a direct interaction between TbmtHMG44 and TbKAP68 and that recombinant TbKAP68 is a DNA binding protein. We thus propose that TbmtHMG44 and TbKAP68 are part of a distinct complex connecting the kDNA to the TAC.
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Affiliation(s)
- Simona Amodeo
- Institute of Cell Biology, University of Bern, Bern, Switzerland
| | - Irina Bregy
- Institute of Cell Biology, University of Bern, Bern, Switzerland
- Graduate School for Cellular and Biomedical Sciences, Bern, Switzerland
- Institute for Anatomy, University of Bern, Bern, Switzerland
| | | | - Albert Fradera-Sola
- Quantitative Proteomics, Institute of Molecular Biology GmbH, Mainz, Germany
| | - Mara Kern
- Institute of Cell Biology, University of Bern, Bern, Switzerland
| | - Hélène Baudouin
- Institute of Cell Biology, University of Bern, Bern, Switzerland
| | - Benoît Zuber
- Institute for Anatomy, University of Bern, Bern, Switzerland
| | - Falk Butter
- Quantitative Proteomics, Institute of Molecular Biology GmbH, Mainz, Germany
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20
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Dubey AP, Tylec BL, Mishra A, Sortino K, Chen R, Sun Y, Read LK. KREH1 RNA helicase activity promotes utilization of initiator gRNAs across multiple mRNAs in trypanosome RNA editing. Nucleic Acids Res 2023; 51:5791-5809. [PMID: 37140035 PMCID: PMC10287954 DOI: 10.1093/nar/gkad292] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Revised: 04/04/2023] [Accepted: 04/11/2023] [Indexed: 05/05/2023] Open
Abstract
Mitochondrial U-indel RNA editing in kinetoplastid protozoa is directed by trans-acting gRNAs and mediated by a holoenzyme with associated factors. Here, we examine the function of the holoenzyme-associated KREH1 RNA helicase in U-indel editing. We show that KREH1 knockout (KO) impairs editing of a small subset of mRNAs. Overexpression of helicase-dead mutants results in expanded impairment of editing across multiple transcripts, suggesting the existence of enzymes that can compensate for KREH1 in KO cells. In depth analysis of editing defects using quantitative RT-PCR and high-throughput sequencing reveals compromised editing initiation and progression in both KREH1-KO and mutant-expressing cells. In addition, these cells exhibit a distinct defect in the earliest stages of editing in which the initiator gRNA is bypassed, and a small number of editing events takes place just outside this region. Wild type KREH1 and a helicase-dead KREH1 mutant interact similarly with RNA and holoenzyme, and overexpression of both similarly disorders holoenzyme homeostasis. Thus, our data support a model in which KREH1 RNA helicase activity facilitates remodeling of initiator gRNA-mRNA duplexes to permit accurate utilization of initiating gRNAs on multiple transcripts.
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Affiliation(s)
- Ashutosh P Dubey
- Dept. of Microbiology and Immunology, Jacobs School of Medicine and Biomedical Sciences, Buffalo, NY 14203, USA
| | - Brianna L Tylec
- Dept. of Microbiology and Immunology, Jacobs School of Medicine and Biomedical Sciences, Buffalo, NY 14203, USA
| | - Amartya Mishra
- Dept. of Microbiology and Immunology, Jacobs School of Medicine and Biomedical Sciences, Buffalo, NY 14203, USA
| | - Katherine Sortino
- Dept. of Microbiology and Immunology, Jacobs School of Medicine and Biomedical Sciences, Buffalo, NY 14203, USA
| | - Runpu Chen
- Dept. of Microbiology and Immunology, Jacobs School of Medicine and Biomedical Sciences, Buffalo, NY 14203, USA
| | - Yijun Sun
- Dept. of Microbiology and Immunology, Jacobs School of Medicine and Biomedical Sciences, Buffalo, NY 14203, USA
| | - Laurie K Read
- Dept. of Microbiology and Immunology, Jacobs School of Medicine and Biomedical Sciences, Buffalo, NY 14203, USA
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21
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Davidge B, McDermott SM, Carnes J, Lewis I, Tracy M, Stuart KD. Multiple domains of the integral KREPA3 protein are critical for the structure and precise functions of RNA Editing Catalytic Complexes in Trypanosoma brucei. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.04.19.537538. [PMID: 37131796 PMCID: PMC10153193 DOI: 10.1101/2023.04.19.537538] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
The gRNA directed U-insertion and deletion editing of mitochondrial mRNAs that is essential in different life cycle stages for the protozoan parasite Trypanosoma brucei is performed by three similar multi-protein catalytic complexes (CCs) that contain the requisite enzymes. These CCs also contain a common set of eight proteins that have no apparent direct catalytic function, including six that have an OB-fold domain. We show here that one of these OB-fold proteins, KREPA3 (A3), has structural homology to other editing proteins, is essential for editing and is multifunctional. We investigated A3 function by analyzing the effects of single amino acid loss of function mutations most of which were identified by screening bloodstream form (BF) parasites for loss of growth following random mutagenesis. Mutations in the ZFs, an intrinsically disordered region (IDR) and several within or near the C-terminal OB-fold domain variably impacted CC structural integrity and editing. Some mutations resulted in almost complete loss of CCs and its proteins and editing whereas others retained CCs but had aberrant editing. All but a mutation which is near the OB-fold affected growth and editing in BF but not procyclic form (PF) parasites. These data indicate that multiple positions within A3 have essential functions that contribute to the structural integrity of CCs, the precision of editing and the developmental differences in editing between BF and PF stages.
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Affiliation(s)
- Brittney Davidge
- Center for Global Infectious Disease Research (CGIDR), Seattle Children's Research Institute, Seattle, WA 98109
| | - Suzanne M McDermott
- Center for Global Infectious Disease Research (CGIDR), Seattle Children's Research Institute, Seattle, WA 98109
- Department of Pediatrics, University of Washington, Seattle, WA
| | - Jason Carnes
- Center for Global Infectious Disease Research (CGIDR), Seattle Children's Research Institute, Seattle, WA 98109
| | - Isaac Lewis
- Center for Global Infectious Disease Research (CGIDR), Seattle Children's Research Institute, Seattle, WA 98109
| | - Maxwell Tracy
- Center for Global Infectious Disease Research (CGIDR), Seattle Children's Research Institute, Seattle, WA 98109
| | - Kenneth D Stuart
- Center for Global Infectious Disease Research (CGIDR), Seattle Children's Research Institute, Seattle, WA 98109
- Department of Pediatrics, University of Washington, Seattle, WA
- Department of Global Health, University of Washington, Seattle, WA
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22
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Salinas R, Cannistraci E, Schumacher MA. Structure of the T. brucei kinetoplastid RNA editing substrate-binding complex core component, RESC5. PLoS One 2023; 18:e0282155. [PMID: 36862634 PMCID: PMC9980740 DOI: 10.1371/journal.pone.0282155] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Accepted: 02/07/2023] [Indexed: 03/03/2023] Open
Abstract
Kinetoplastid protists such as Trypanosoma brucei undergo an unusual process of mitochondrial uridine (U) insertion and deletion editing termed kinetoplastid RNA editing (kRNA editing). This extensive form of editing, which is mediated by guide RNAs (gRNAs), can involve the insertion of hundreds of Us and deletion of tens of Us to form a functional mitochondrial mRNA transcript. kRNA editing is catalyzed by the 20 S editosome/RECC. However, gRNA directed, processive editing requires the RNA editing substrate binding complex (RESC), which is comprised of 6 core proteins, RESC1-RESC6. To date there are no structures of RESC proteins or complexes and because RESC proteins show no homology to proteins of known structure, their molecular architecture remains unknown. RESC5 is a key core component in forming the foundation of the RESC complex. To gain insight into the RESC5 protein we performed biochemical and structural studies. We show that RESC5 is monomeric and we report the T. brucei RESC5 crystal structure to 1.95 Å. RESC5 harbors a dimethylarginine dimethylaminohydrolase-like (DDAH) fold. DDAH enzymes hydrolyze methylated arginine residues produced during protein degradation. However, RESC5 is missing two key catalytic DDAH residues and does bind DDAH substrate or product. Implications of the fold for RESC5 function are discussed. This structure provides the first structural view of an RESC protein.
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Affiliation(s)
- Raul Salinas
- Department of Biochemistry, Duke University School of Medicine, DUMC, Durham, NC, United States of America
| | - Emily Cannistraci
- Department of Biochemistry, Duke University School of Medicine, DUMC, Durham, NC, United States of America
| | - Maria A. Schumacher
- Department of Biochemistry, Duke University School of Medicine, DUMC, Durham, NC, United States of America
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23
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McDermott SM, Pham V, Lewis I, Tracy M, Stuart K. mt-LAF3 is a pseudouridine synthase ortholog required for mitochondrial rRNA and mRNA gene expression in Trypanosoma brucei. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.02.23.529727. [PMID: 36865177 PMCID: PMC9980140 DOI: 10.1101/2023.02.23.529727] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/25/2023]
Abstract
Trypanosoma brucei and related kinetoplastid parasites possess unique RNA processing pathways, including in their mitochondria, that regulate metabolism and development. Altering RNA composition or conformation through nucleotide modifications is one such pathway, and modifications including pseudouridine regulate RNA fate and function in many organisms. We surveyed pseudouridine synthase (PUS) orthologs in Trypanosomatids, with a particular interest in mitochondrial enzymes due to their potential importance for mitochondrial function and metabolism. T. brucei mt-LAF3 is an ortholog of human and yeast mitochondrial PUS enzymes, and a mitoribosome assembly factor, but structural studies differ in their conclusion as to whether it has PUS catalytic activity. Here, we generated T. brucei cells that are conditionally null for mt-LAF3 and showed that mt-LAF3 loss is lethal and disrupts mitochondrial membrane potential (ΔΨm). Addition of a mutant gamma-ATP synthase allele to the conditionally null cells permitted ΔΨm maintenance and cell survival, allowing us to assess primary effects on mitochondrial RNAs. As expected, these studies showed that loss of mt-LAF3 dramatically decreases levels of mitochondrial 12S and 9S rRNAs. Notably, we also observed decreases in mitochondrial mRNA levels, including differential effects on edited vs. pre-edited mRNAs, indicating that mt-LAF3 is required for mitochondrial rRNA and mRNA processing, including of edited transcripts. To assess the importance of PUS catalytic activity in mt-LAF3 we mutated a conserved aspartate that is necessary for catalysis in other PUS enzymes and showed it is not essential for cell growth, or maintenance of ΔΨm and mitochondrial RNA levels. Together, these results indicate that mt-LAF3 is required for normal expression of mitochondrial mRNAs in addition to rRNAs, but that PUS catalytic activity is not required for these functions. Instead, our work, combined with previous structural studies, suggests that T. brucei mt-LAF3 acts as a mitochondrial RNA-stabilizing scaffold.
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Carnes J, Gendrin C, McDermott SM, Stuart K. KRGG1 function in RNA editing in Trypanosoma brucei. RNA (NEW YORK, N.Y.) 2023; 29:228-240. [PMID: 36400448 PMCID: PMC9891254 DOI: 10.1261/rna.079418.122] [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: 08/15/2022] [Accepted: 11/11/2022] [Indexed: 05/20/2023]
Abstract
Mitochondrial gene expression in trypanosomes requires numerous multiprotein complexes that are unique to kinetoplastids. Among these, the most well characterized are RNA editing catalytic complexes (RECCs) that catalyze the guide RNA (gRNA)-specified insertion and deletion of uridines during mitochondrial mRNA maturation. This post-transcriptional resequencing of mitochondrial mRNAs can be extensive, involving dozens of different gRNAs and hundreds of editing sites with most of the mature mRNA sequences resulting from the editing process. Proper coordination of the editing with the cognate gRNAs is attributed to RNA editing substrate-binding complexes (RESCs), which are also required for RNA editing. Although the precise mechanism of RESC function is less well understood, their affinity for binding both editing substrates and products suggests that these complexes may provide a scaffold for RECC catalytic processing. KRGG1 has been shown to bind RNAs, and although affinity purification co-isolates RESC complexes, its role in RNA editing remains uncertain. We show here that KRGG1 is essential in BF parasites and required for normal editing. KRGG1 repression results in reduced amounts of edited A6 mRNA and increased amounts of edited ND8 mRNA. Sequence and structure analysis of KRGG1 identified a region of homology with RESC6, and both proteins have predicted tandem helical repeats that resemble ARM/HEAT motifs. The ARM/HEAT-like region is critical for function as exclusive expression of mutated KRGG1 results in growth inhibition and disruption of KRGG1 association with RESCs. These results indicate that KRGG1 is critical for RNA editing and its specific function is associated with RESC activity.
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Affiliation(s)
- Jason Carnes
- Seattle Children's Research Institute, Seattle, Washington 98109, USA
| | - Claire Gendrin
- Seattle Children's Research Institute, Seattle, Washington 98109, USA
| | | | - Kenneth Stuart
- Seattle Children's Research Institute, Seattle, Washington 98109, USA
- Department of Pediatrics and Global Health, University of Washington, Seattle, Washington 98105, USA
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25
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Rostamighadi M, Mehta V, Hassan Khan R, Moses D, Salavati R. Hammerhead ribozyme-based U-insertion and deletion RNA editing assays for multiplexing in HTS applications. RNA (NEW YORK, N.Y.) 2023; 29:252-261. [PMID: 36456183 PMCID: PMC9891259 DOI: 10.1261/rna.079454.122] [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: 09/29/2022] [Accepted: 11/18/2022] [Indexed: 05/14/2023]
Abstract
Untranslatable mitochondrial transcripts in kinetoplastids are decrypted post-transcriptionally through an RNA editing process that entails uridine insertion/deletion. This unique stepwise process is mediated by the editosome, a multiprotein complex that is a validated drug target of considerable interest in addressing the unmet medical needs for kinetoplastid diseases. With that objective, several in vitro RNA editing assays have been developed, albeit with limited success in discovering potent inhibitors. This manuscript describes the development of three hammerhead ribozyme (HHR) FRET reporter-based RNA editing assays for precleaved deletion, insertion, and ligation assays that bypass the rate-limiting endonucleolytic cleavage step, providing information on U-deletion, U-insertion, and ligation activities. These assays exhibit higher editing efficiencies in shorter incubation times while requiring significantly less purified editosome and 10,000-fold less ATP than the previously published full round of in vitro RNA editing assay. Moreover, modifications in the reporter ribozyme sequence enable the feasibility of multiplexing a ribozyme-based insertion/deletion editing (RIDE) assay that simultaneously surveils U-insertion and deletion editing suitable for HTS. These assays can be used to find novel chemical compounds with chemotherapeutic applications or as probes for studying the editosome machinery.
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Affiliation(s)
- Mojtaba Rostamighadi
- Institute of Parasitology, McGill University, Ste. Anne de Bellevue, Quebec, Canada H9X 3V9
| | - Vaibhav Mehta
- Institute of Parasitology, McGill University, Ste. Anne de Bellevue, Quebec, Canada H9X 3V9
- Department of Biochemistry, McGill University, Montreal, Quebec, Canada H3G 1Y6
| | - Rufaida Hassan Khan
- Institute of Parasitology, McGill University, Ste. Anne de Bellevue, Quebec, Canada H9X 3V9
| | - Daniel Moses
- Institute of Parasitology, McGill University, Ste. Anne de Bellevue, Quebec, Canada H9X 3V9
| | - Reza Salavati
- Institute of Parasitology, McGill University, Ste. Anne de Bellevue, Quebec, Canada H9X 3V9
- Department of Biochemistry, McGill University, Montreal, Quebec, Canada H3G 1Y6
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26
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Carnes J, McDermott SM, Lewis I, Tracy M, Stuart K. Domain function and predicted structure of three heterodimeric endonuclease subunits of RNA editing catalytic complexes in Trypanosoma brucei. Nucleic Acids Res 2022; 50:10123-10139. [PMID: 36095119 PMCID: PMC9508840 DOI: 10.1093/nar/gkac753] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2021] [Revised: 08/18/2022] [Accepted: 08/24/2022] [Indexed: 11/13/2022] Open
Abstract
Each of the three similar RNA Editing Catalytic Complexes (RECCs) that perform gRNA-directed uridine insertion and deletion during Trypanosoma brucei mitochondrial (mt) mRNA editing has a distinct endonuclease activity that requires two related RNase III proteins, with only one competent for catalysis. We identified multiple loss-of-function mutations in the RNase III and other motifs of the non-catalytic KREPB6, KREPB7, and KREPB8 components by random mutagenesis and screening. These mutations had various effects on growth, editing, and both the abundances and RECC associations of these RNase III protein pairs in bloodstream form (BF) and procyclic form (PF) cells. Protein structure modelling predicted that the Zinc Finger (ZnF) of each paired RNase III protein contacts RNA positioned at the heterodimeric active site which is flanked by helices of a novel RNase III-Associated Motif (RAM). The results indicate that the protein domains of the non-catalytic subunits function together in RECC integrity, substrate binding, and editing site recognition during the multistep RNA editing process. Additionally, several mutants display distinct functional consequences in different life cycle stages. These results highlight the complementary roles of protein pairs and three RECCs within the complicated T. brucei mRNA editing machinery that matures mt mRNAs differentially between developmental stages.
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Affiliation(s)
- Jason Carnes
- Seattle Children's Research Institute, Seattle, WA, USA
| | - Suzanne M McDermott
- Seattle Children's Research Institute, Seattle, WA, USA
- Department of Pediatrics, University of Washington School of Medicine, Seattle, WA, USA
| | - Isaac Lewis
- Seattle Children's Research Institute, Seattle, WA, USA
| | - Maxwell Tracy
- Seattle Children's Research Institute, Seattle, WA, USA
| | - Kenneth Stuart
- Seattle Children's Research Institute, Seattle, WA, USA
- Department of Pediatrics, University of Washington School of Medicine, Seattle, WA, USA
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27
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Cooper S, Wadsworth ES, Schnaufer A, Savill NJ. Organization of minicircle cassettes and guide RNA genes in Trypanosoma brucei. RNA (NEW YORK, N.Y.) 2022; 28:972-992. [PMID: 35414587 PMCID: PMC9202587 DOI: 10.1261/rna.079022.121] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Accepted: 03/27/2022] [Indexed: 06/14/2023]
Abstract
Mitochondrial DNA of protists of order Kinetoplastida comprises thousands of interlinked circular molecules arranged in a network. There are two types of molecules called minicircles and maxicircles. Minicircles encode guide RNA (gRNA) genes whose transcripts mediate post-transcriptional editing of maxicircle encoded genes. Minicircles are diverse. The human sleeping sickness parasite Trypanosoma brucei has one of the most diverse sets of minicircle classes of all studied trypanosomatids with hundreds of different classes, each encoding one to four genes mainly within cassettes framed by 18 bp inverted repeats. A third of cassettes have no identifiable gRNA genes even though their sequence structures are similar to cassettes with identifiable genes. Only recently have almost all minicircle classes for some subspecies and isolates of T. brucei been sequenced and annotated with corresponding verification of gRNA expression by small-RNA transcriptome data. These data sets provide a rich resource for understanding the structure of minicircle classes, cassettes and gRNA genes and their transcription. Here, we provide a statistical description of the functionality, expression status, structure and sequence of gRNA genes in a differentiation-competent, laboratory-adapted strain of T. brucei We obtain a clearer definition of what is a gRNA gene. Our analysis supports the idea that many, if not all, cassettes without an identifiable gRNA gene contain decaying remnants of once functional gRNA genes. Finally, we report several new, unexplained discoveries such as the association between cassette position on the minicircle and gene expression and functionality, and the association between gene initiation sequence and anchor position.
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Affiliation(s)
- Sinclair Cooper
- Institute of Immunology and Infection Research, University of Edinburgh, Edinburgh, Scotland EH9 3FL, United Kingdom
| | - Elizabeth S Wadsworth
- Institute of Immunology and Infection Research, University of Edinburgh, Edinburgh, Scotland EH9 3FL, United Kingdom
| | - Achim Schnaufer
- Institute of Immunology and Infection Research, University of Edinburgh, Edinburgh, Scotland EH9 3FL, United Kingdom
| | - Nicholas J Savill
- Institute of Immunology and Infection Research, University of Edinburgh, Edinburgh, Scotland EH9 3FL, United Kingdom
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28
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Solana JC, Chicharro C, García E, Aguado B, Moreno J, Requena JM. Assembly of a Large Collection of Maxicircle Sequences and Their Usefulness for Leishmania Taxonomy and Strain Typing. Genes (Basel) 2022; 13:genes13061070. [PMID: 35741832 PMCID: PMC9222942 DOI: 10.3390/genes13061070] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Revised: 06/10/2022] [Accepted: 06/13/2022] [Indexed: 11/28/2022] Open
Abstract
Parasites of medical importance, such as Leishmania and Trypanosoma, are characterized by the presence of thousands of circular DNA molecules forming a structure known as kinetoplast, within the mitochondria. The maxicircles, which are equivalent to the mitochondrial genome in other eukaryotes, have been proposed as a promising phylogenetic marker. Using whole-DNA sequencing data, it is also possible to assemble maxicircle sequences as shown here and in previous works. In this study, based on data available in public databases and using a bioinformatics workflow previously reported by our group, we assembled the complete coding region of the maxicircles for 26 prototypical strains of trypanosomatid species. Phylogenetic analysis based on this dataset resulted in a robust tree showing an accurate taxonomy of kinetoplastids, which was also able to discern between closely related Leishmania species that are usually difficult to discriminate by classical methodologies. In addition, we provide a dataset of the maxicircle sequences of 60 Leishmania infantum field isolates from America, Western Europe, North Africa, and Eastern Europe. In agreement with previous studies, our data indicate that L. infantum parasites from Brazil are highly homogeneous and closely related to European strains, which were transferred there during the discovery of America. However, this study showed the existence of different L. infantum populations/clades within the Mediterranean region. A maxicircle signature for each clade has been established. Interestingly, two L. infantum clades were found coexisting in the same region of Spain, one similar to the American strains, represented by the Spanish JPCM5 reference strain, and the other, named “non-JPC like”, may be related to an important leishmaniasis outbreak that occurred in Madrid a few years ago. In conclusion, the maxicircle sequence emerges as a robust molecular marker for phylogenetic analysis and species typing within the kinetoplastids, which also has the potential to discriminate intraspecific variability.
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Affiliation(s)
- Jose Carlos Solana
- Centro de Biología Molecular Severo Ochoa (CSIC-UAM), Departamento de Biología Molecular, Instituto Universitario de Biología Molecular (IUBM), Universidad Autónoma de Madrid, 28049 Madrid, Spain;
- WHO Collaborating Centre for Leishmaniasis, Centro Nacional de Microbiología, Instituto de Salud Carlos III, Majadahonda, 28220 Madrid, Spain; (C.C.); (E.G.)
- Centro de Investigación Biomédica en Red de Enfermedades Infecciosas (CIBERINFEC), Instituto de Salud Carlos III, 28029 Madrid, Spain
| | - Carmen Chicharro
- WHO Collaborating Centre for Leishmaniasis, Centro Nacional de Microbiología, Instituto de Salud Carlos III, Majadahonda, 28220 Madrid, Spain; (C.C.); (E.G.)
- Centro de Investigación Biomédica en Red de Enfermedades Infecciosas (CIBERINFEC), Instituto de Salud Carlos III, 28029 Madrid, Spain
| | - Emilia García
- WHO Collaborating Centre for Leishmaniasis, Centro Nacional de Microbiología, Instituto de Salud Carlos III, Majadahonda, 28220 Madrid, Spain; (C.C.); (E.G.)
| | - Begoña Aguado
- Centro de Biología Molecular Severo Ochoa (CSIC-UAM), Genomic and NGS Facility (GENGS), 28049 Madrid, Spain;
| | - Javier Moreno
- WHO Collaborating Centre for Leishmaniasis, Centro Nacional de Microbiología, Instituto de Salud Carlos III, Majadahonda, 28220 Madrid, Spain; (C.C.); (E.G.)
- Centro de Investigación Biomédica en Red de Enfermedades Infecciosas (CIBERINFEC), Instituto de Salud Carlos III, 28029 Madrid, Spain
- Correspondence: (J.M.); (J.M.R.)
| | - Jose M. Requena
- Centro de Biología Molecular Severo Ochoa (CSIC-UAM), Departamento de Biología Molecular, Instituto Universitario de Biología Molecular (IUBM), Universidad Autónoma de Madrid, 28049 Madrid, Spain;
- Centro de Investigación Biomédica en Red de Enfermedades Infecciosas (CIBERINFEC), Instituto de Salud Carlos III, 28029 Madrid, Spain
- Correspondence: (J.M.); (J.M.R.)
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29
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Dewar CE, Oeljeklaus S, Mani J, Mühlhäuser WWD, von Känel C, Zimmermann J, Ochsenreiter T, Warscheid B, Schneider A. Mistargeting of aggregation prone mitochondrial proteins activates a nucleus-mediated posttranscriptional quality control pathway in trypanosomes. Nat Commun 2022; 13:3084. [PMID: 35654893 PMCID: PMC9163028 DOI: 10.1038/s41467-022-30748-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2021] [Accepted: 05/02/2022] [Indexed: 12/25/2022] Open
Abstract
Mitochondrial protein import in the parasitic protozoan Trypanosoma brucei is mediated by the atypical outer membrane translocase, ATOM. It consists of seven subunits including ATOM69, the import receptor for hydrophobic proteins. Ablation of ATOM69, but not of any other subunit, triggers a unique quality control pathway resulting in the proteasomal degradation of non-imported mitochondrial proteins. The process requires a protein of unknown function, an E3 ubiquitin ligase and the ubiquitin-like protein (TbUbL1), which all are recruited to the mitochondrion upon ATOM69 depletion. TbUbL1 is a nuclear protein, a fraction of which is released to the cytosol upon triggering of the pathway. Nuclear release is essential as cytosolic TbUbL1 can bind mislocalised mitochondrial proteins and likely transfers them to the proteasome. Mitochondrial quality control has previously been studied in yeast and metazoans. Finding such a pathway in the highly diverged trypanosomes suggests such pathways are an obligate feature of all eukaryotes. Mitochondria import most of their proteins posttranslationally. Here, Dewar et al. characterize the mitochondrial quality control mechanism of Trypanosoma brucei. Through proteomics and functional studies, they show that only ablation of ATOM69, one of the seven subunits of its mitochondrial protein translocase, triggers a unique quality control pathway resulting in TbUbL1 release from the nucleus and subsequent proteasomal degradation of non-imported mitochondrial proteins.
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Affiliation(s)
- Caroline E Dewar
- Department of Chemistry, Biochemistry and Pharmaceutical Sciences, University of Bern, Freiestrasse 3, Bern, CH-3012, Switzerland
| | - Silke Oeljeklaus
- Faculty of Chemistry and Pharmacy, Department of Biochemistry, Theodor Boveri-Institute, University of Würzburg, 97074, Würzburg, Germany.,Biochemistry and Functional Proteomics, Institute of Biology II, Faculty of Biology, University of Freiburg, 79104, Freiburg, Germany
| | - Jan Mani
- Department of Chemistry, Biochemistry and Pharmaceutical Sciences, University of Bern, Freiestrasse 3, Bern, CH-3012, Switzerland
| | - Wignand W D Mühlhäuser
- Biochemistry and Functional Proteomics, Institute of Biology II, Faculty of Biology, University of Freiburg, 79104, Freiburg, Germany
| | - Corinne von Känel
- Department of Chemistry, Biochemistry and Pharmaceutical Sciences, University of Bern, Freiestrasse 3, Bern, CH-3012, Switzerland
| | - Johannes Zimmermann
- Faculty of Chemistry and Pharmacy, Department of Biochemistry, Theodor Boveri-Institute, University of Würzburg, 97074, Würzburg, Germany
| | - Torsten Ochsenreiter
- Institute of Cell Biology, University of Bern, Baltzerstrasse 4, Bern, CH-3012, Switzerland
| | - Bettina Warscheid
- Faculty of Chemistry and Pharmacy, Department of Biochemistry, Theodor Boveri-Institute, University of Würzburg, 97074, Würzburg, Germany. .,Biochemistry and Functional Proteomics, Institute of Biology II, Faculty of Biology, University of Freiburg, 79104, Freiburg, Germany. .,CIBSS Centre for Integrative Biological Signalling Studies, University of Freiburg, 79104, Freiburg, Germany.
| | - André Schneider
- Department of Chemistry, Biochemistry and Pharmaceutical Sciences, University of Bern, Freiestrasse 3, Bern, CH-3012, Switzerland.
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30
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Oxidative Phosphorylation Is Required for Powering Motility and Development of the Sleeping Sickness Parasite Trypanosoma brucei in the Tsetse Fly Vector. mBio 2022; 13:e0235721. [PMID: 35012336 PMCID: PMC8749461 DOI: 10.1128/mbio.02357-21] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The single-celled parasite Trypanosoma brucei is transmitted by hematophagous tsetse flies. Life cycle progression from mammalian bloodstream form to tsetse midgut form and, subsequently, infective salivary gland form depends on complex developmental steps and migration within different fly tissues. As the parasite colonizes the glucose-poor insect midgut, ATP production is thought to depend on activation of mitochondrial amino acid catabolism via oxidative phosphorylation (OXPHOS). This process involves respiratory chain complexes and F1Fo-ATP synthase and requires protein subunits of these complexes that are encoded in the parasite's mitochondrial DNA (kDNA). Here, we show that progressive loss of kDNA-encoded functions correlates with a decreasing ability to initiate and complete development in the tsetse. First, parasites with a mutated F1Fo-ATP synthase with reduced capacity for OXPHOS can initiate differentiation from bloodstream to insect form, but they are unable to proliferate in vitro. Unexpectedly, these cells can still colonize the tsetse midgut. However, these parasites exhibit a motility defect and are severely impaired in colonizing or migrating to subsequent tsetse tissues. Second, parasites with a fully disrupted F1Fo-ATP synthase complex that is completely unable to produce ATP by OXPHOS can still differentiate to the first insect stage in vitro but die within a few days and cannot establish a midgut infection in vivo. Third, parasites lacking kDNA entirely can initiate differentiation but die soon after. Together, these scenarios suggest that efficient ATP production via OXPHOS is not essential for initial colonization of the tsetse vector but is required to power trypanosome migration within the fly. IMPORTANCE African trypanosomes cause disease in humans and their livestock and are transmitted by tsetse flies. The insect ingests these parasites with its blood meal, but to be transmitted to another mammal, the trypanosome must undergo complex development within the tsetse fly and migrate from the insect's gut to its salivary glands. Crucially, the parasite must switch from a sugar-based diet while in the mammal to a diet based primarily on amino acids when it develops in the insect. Here, we show that efficient energy production by an organelle called the mitochondrion is critical for the trypanosome's ability to swim and to migrate through the tsetse fly. Surprisingly, trypanosomes with impaired mitochondrial energy production are only mildly compromised in their ability to colonize the tsetse fly midgut. Our study adds a new perspective to the emerging view that infection of tsetse flies by trypanosomes is more complex than previously thought.
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A novel high-content phenotypic screen to identify inhibitors of mitochondrial DNA maintenance in trypanosomes. Antimicrob Agents Chemother 2021; 66:e0198021. [PMID: 34871097 PMCID: PMC8846439 DOI: 10.1128/aac.01980-21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Kinetoplastid parasites cause diverse neglected diseases in humans and livestock, with an urgent need for new treatments. The survival of kinetoplastids depends on their uniquely structured mitochondrial genome (kDNA), the eponymous kinetoplast. Here, we report the development of a high-content screen for pharmacologically induced kDNA loss, based on specific staining of parasites and automated image analysis. As proof of concept, we screened a diverse set of ∼14,000 small molecules and exemplify a validated hit as a novel kDNA-targeting compound.
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Prasadareddy Kajuluri L, Singh A, Bajpai R, Kumar Veluru N, Mitra K, Sahasrabuddhe AA. Actin-related protein 4: An unconventional negative regulator of mitochondrial calcium in protozoan parasite Leishmania. Mitochondrion 2021; 62:31-40. [PMID: 34752857 DOI: 10.1016/j.mito.2021.11.001] [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] [Received: 03/31/2021] [Revised: 10/08/2021] [Accepted: 11/01/2021] [Indexed: 01/10/2023]
Abstract
Regulation of mitochondrial calcium import is less understood in evolutionarily distinct protozoan parasites, such as Leishmania, as some of the mitochondrial calcium uniporter complex proteins are either missing or functionally diverged. Here, we show that Actin-related protein4 (ARP4), localizes exclusively into the Leishmania mitochondrion and depletion of this protein causes cells to accumulate calcium in the mitochondrion. The ARP4 depleted cells show increased activation of pyruvate dehydrogenase and production of ATP. Overall, our results indicate that ARP4 negatively regulates calcium uptake in the Leishmania mitochondrion.
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Affiliation(s)
| | - Aastha Singh
- Molecular and Structural Biology Division, CSIR-Central Drug Research Institute, Lucknow, India
| | - Ranju Bajpai
- Molecular and Structural Biology Division, CSIR-Central Drug Research Institute, Lucknow, India
| | - Niranjan Kumar Veluru
- Molecular and Structural Biology Division, CSIR-Central Drug Research Institute, Lucknow, India
| | - Kalyan Mitra
- Electron Microscopy Unit, Sophisticated Analytical Instrumentation Facility, CSIR-Central Drug Research Institute, Lucknow, India
| | - Amogh A Sahasrabuddhe
- Molecular and Structural Biology Division, CSIR-Central Drug Research Institute, Lucknow, India.
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Rajan KS, Adler K, Madmoni H, Peleg-Chen D, Cohen-Chalamish S, Doniger T, Galili B, Gerber D, Unger R, Tschudi C, Michaeli S. Pseudouridines on Trypanosoma brucei mRNAs are developmentally regulated: Implications to mRNA stability and protein binding. Mol Microbiol 2021; 116:808-826. [PMID: 34165831 DOI: 10.1111/mmi.14774] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2020] [Revised: 05/11/2021] [Accepted: 06/17/2021] [Indexed: 11/30/2022]
Abstract
The parasite Trypanosoma brucei cycles between an insect and a mammalian host and is the causative agent of sleeping sickness. Here, we performed high-throughput mapping of pseudouridines (Ψs) on mRNA from two life stages of the parasite. The analysis revealed ~273 Ψs, including developmentally regulated Ψs that are guided by homologs of pseudouridine synthases (PUS1, 3, 5, and 7). Mutating the U that undergoes pseudouridylation in the 3' UTR of valyl-tRNA synthetase destabilized the mRNA level. To investigate the mechanism by which Ψ affects the stability of this mRNA, proteins that bind to the 3' UTR were identified, including the RNA binding protein RBSR1. The binding of RBSR1 protein to the 3' UTR was stronger when lacking Ψ compared to transcripts carrying the modification, suggesting that Ψ can inhibit the binding of proteins to their target and thus affect the stability of mRNAs. Consequently, Ψ modification on mRNA adds an additional level of regulation to the dominant post-transcriptional control in these parasites.
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Affiliation(s)
- K Shanmugha Rajan
- The Mina and Everard Goodman Faculty of Life Sciences and Advanced Materials and Nanotechnology Institute, Bar-Ilan University, Ramat-Gan, Israel
| | - Katerina Adler
- The Mina and Everard Goodman Faculty of Life Sciences and Advanced Materials and Nanotechnology Institute, Bar-Ilan University, Ramat-Gan, Israel
| | - Hava Madmoni
- The Mina and Everard Goodman Faculty of Life Sciences and Advanced Materials and Nanotechnology Institute, Bar-Ilan University, Ramat-Gan, Israel
| | - Dana Peleg-Chen
- The Mina and Everard Goodman Faculty of Life Sciences and Advanced Materials and Nanotechnology Institute, Bar-Ilan University, Ramat-Gan, Israel
| | - Smadar Cohen-Chalamish
- The Mina and Everard Goodman Faculty of Life Sciences and Advanced Materials and Nanotechnology Institute, Bar-Ilan University, Ramat-Gan, Israel
| | - Tirza Doniger
- The Mina and Everard Goodman Faculty of Life Sciences and Advanced Materials and Nanotechnology Institute, Bar-Ilan University, Ramat-Gan, Israel
| | - Beathrice Galili
- The Mina and Everard Goodman Faculty of Life Sciences and Advanced Materials and Nanotechnology Institute, Bar-Ilan University, Ramat-Gan, Israel
| | - Doron Gerber
- The Mina and Everard Goodman Faculty of Life Sciences and Advanced Materials and Nanotechnology Institute, Bar-Ilan University, Ramat-Gan, Israel
| | - Ron Unger
- The Mina and Everard Goodman Faculty of Life Sciences and Advanced Materials and Nanotechnology Institute, Bar-Ilan University, Ramat-Gan, Israel
| | - Christian Tschudi
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, CT, USA
| | - Shulamit Michaeli
- The Mina and Everard Goodman Faculty of Life Sciences and Advanced Materials and Nanotechnology Institute, Bar-Ilan University, Ramat-Gan, Israel
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Gerasimov ES, Gasparyan AA, Afonin DA, Zimmer SL, Kraeva N, Lukeš J, Yurchenko V, Kolesnikov A. Complete minicircle genome of Leptomonas pyrrhocoris reveals sources of its non-canonical mitochondrial RNA editing events. Nucleic Acids Res 2021; 49:3354-3370. [PMID: 33660779 PMCID: PMC8034629 DOI: 10.1093/nar/gkab114] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2020] [Revised: 02/03/2021] [Accepted: 02/09/2021] [Indexed: 01/24/2023] Open
Abstract
Uridine insertion/deletion (U-indel) editing of mitochondrial mRNA, unique to the protistan class Kinetoplastea, generates canonical as well as potentially non-productive editing events. While the molecular machinery and the role of the guide (g) RNAs that provide required information for U-indel editing are well understood, little is known about the forces underlying its apparently error-prone nature. Analysis of a gRNA:mRNA pair allows the dissection of editing events in a given position of a given mitochondrial transcript. A complete gRNA dataset, paired with a fully characterized mRNA population that includes non-canonically edited transcripts, would allow such an analysis to be performed globally across the mitochondrial transcriptome. To achieve this, we have assembled 67 minicircles of the insect parasite Leptomonas pyrrhocoris, with each minicircle typically encoding one gRNA located in one of two similar-sized units of different origin. From this relatively narrow set of annotated gRNAs, we have dissected all identified mitochondrial editing events in L. pyrrhocoris, the strains of which dramatically differ in the abundance of individual minicircle classes. Our results support a model in which a multitude of editing events are driven by a limited set of gRNAs, with individual gRNAs possessing an inherent ability to guide canonical and non-canonical editing.
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Affiliation(s)
- Evgeny S Gerasimov
- Faculty of Biology, M.V. Lomonosov Moscow State University, Moscow 119991, Russia
- Martsinovsky Institute of Medical Parasitology, Tropical and Vector Borne Diseases, Sechenov University, Moscow 119435, Russia
- Institute for Information Transmission Problems, Russian Academy of Sciences, Moscow 127051, Russia
| | - Anna A Gasparyan
- Faculty of Biology, M.V. Lomonosov Moscow State University, Moscow 119991, Russia
| | - Dmitry A Afonin
- Faculty of Biology, M.V. Lomonosov Moscow State University, Moscow 119991, Russia
| | - Sara L Zimmer
- Department of Biomedical Sciences, University of Minnesota Medical School, Duluth Campus, Duluth, MN 55812, USA
| | - Natalya Kraeva
- Life Science Research Centre, Faculty of Science, University of Ostrava, 710 00 Ostrava, Czech Republic
| | - Julius Lukeš
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, 370 05 České Budějovice (Budweis), Czech Republic
- Faculty of Science, University of South Bohemia, 370 05 České Budějovice (Budweis), Czech Republic
| | - Vyacheslav Yurchenko
- Martsinovsky Institute of Medical Parasitology, Tropical and Vector Borne Diseases, Sechenov University, Moscow 119435, Russia
- Life Science Research Centre, Faculty of Science, University of Ostrava, 710 00 Ostrava, Czech Republic
| | - Alexander Kolesnikov
- Faculty of Biology, M.V. Lomonosov Moscow State University, Moscow 119991, Russia
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Dubey AP, Tylec BL, McAdams NM, Sortino K, Read L. Trypanosome RNAEditing Substrate Binding Complex integrity and function depends on the upstream action of RESC10. Nucleic Acids Res 2021; 49:3557-3572. [PMID: 33677542 PMCID: PMC8034615 DOI: 10.1093/nar/gkab129] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2020] [Revised: 02/11/2021] [Accepted: 02/17/2021] [Indexed: 01/17/2023] Open
Abstract
Uridine insertion/deletion editing of mitochondrial mRNAs is a characteristic feature of kinetoplastids, including Trypanosoma brucei. Editing is directed by trans-acting gRNAs and catalyzed by related RNA Editing Core Complexes (RECCs). The non-catalytic RNA Editing Substrate Binding Complex (RESC) coordinates interactions between RECC, gRNA and mRNA. RESC is a dynamic complex comprising GRBC (Guide RNA Binding Complex) and heterogeneous REMCs (RNA Editing Mediator Complexes). Here, we show that RESC10 is an essential, low abundance, RNA binding protein that exhibits RNase-sensitive and RNase-insensitive interactions with RESC proteins, albeit its minimal in vivo interaction with RESC13. RESC10 RNAi causes extensive RESC disorganization, including disruption of intra-GRBC protein-protein interactions, as well as mRNA depletion from GRBC and accumulation on REMCs. Analysis of mitochondrial RNAs at single nucleotide resolution reveals transcript-specific effects: RESC10 dramatically impacts editing progression in pan-edited RPS12 mRNA, but is critical for editing initiation in mRNAs with internally initiating gRNAs, pointing to distinct initiation mechanisms for these RNA classes. Correlations between sites at which editing pauses in RESC10 depleted cells and those in knockdowns of previously studied RESC proteins suggest that RESC10 acts upstream of these factors and that RESC is particularly important in promoting transitions between uridine insertion and deletion RECCs.
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Affiliation(s)
- Ashutosh P Dubey
- Department of Microbiology and Immunology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, NY 14203, USA
| | - Brianna L Tylec
- Department of Microbiology and Immunology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, NY 14203, USA
| | - Natalie M McAdams
- Department of Microbiology and Immunology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, NY 14203, USA
| | - Katherine Sortino
- Department of Microbiology and Immunology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, NY 14203, USA
| | - Laurie K Read
- Department of Microbiology and Immunology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, NY 14203, USA
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Amodeo S, Kalichava A, Fradera-Sola A, Bertiaux-Lequoy E, Guichard P, Butter F, Ochsenreiter T. Characterization of the novel mitochondrial genome segregation factor TAP110 in Trypanosoma brucei. J Cell Sci 2021; 134:jcs254300. [PMID: 33589495 PMCID: PMC7970207 DOI: 10.1242/jcs.254300] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Accepted: 02/03/2021] [Indexed: 12/18/2022] Open
Abstract
Proper mitochondrial genome inheritance is important for eukaryotic cell survival. Trypanosoma brucei, a protozoan parasite, contains a singular mitochondrial genome, the kinetoplast (k)DNA. The kDNA is anchored to the basal body via the tripartite attachment complex (TAC) to ensure proper segregation. Several components of the TAC have been described; however, the connection of the TAC to the kDNA remains elusive. Here, we characterize the TAC-associated protein TAP110. We find that both depletion and overexpression of TAP110 leads to a delay in the separation of the replicated kDNA networks. Proteome analysis after TAP110 overexpression identified several kDNA-associated proteins that changed in abundance, including a TEX-like protein that dually localizes to the nucleus and the kDNA, potentially linking replication and segregation in the two compartments. The assembly of TAP110 into the TAC region seems to require the TAC but not the kDNA itself; however, once TAP110 has been assembled, it also interacts with the kDNA. Finally, we use ultrastructure expansion microscopy in trypanosomes for the first time, and reveal the precise position of TAP110 between TAC102 and the kDNA, showcasing the potential of this approach.This article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
- Simona Amodeo
- Institute of Cell Biology, University of Bern, 3012 Bern, Switzerland
- Graduate School for Cellular and Biomedical Sciences, University of Bern, 3012 Bern, Switzerland
| | - Ana Kalichava
- Institute of Cell Biology, University of Bern, 3012 Bern, Switzerland
- Graduate School for Cellular and Biomedical Sciences, University of Bern, 3012 Bern, Switzerland
| | | | - Eloïse Bertiaux-Lequoy
- Department of Cell Biology, University of Geneva, Sciences III, 1211 Geneva, Switzerland
| | - Paul Guichard
- Department of Cell Biology, University of Geneva, Sciences III, 1211 Geneva, Switzerland
| | - Falk Butter
- Institute of Molecular Biology, 55128 Mainz, Germany
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Schaefer MR. The Regulation of RNA Modification Systems: The Next Frontier in Epitranscriptomics? Genes (Basel) 2021; 12:genes12030345. [PMID: 33652758 PMCID: PMC7996938 DOI: 10.3390/genes12030345] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2021] [Revised: 02/22/2021] [Accepted: 02/24/2021] [Indexed: 12/12/2022] Open
Abstract
RNA modifications, long considered to be molecular curiosities embellishing just abundant and non-coding RNAs, have now moved into the focus of both academic and applied research. Dedicated research efforts (epitranscriptomics) aim at deciphering the underlying principles by determining RNA modification landscapes and investigating the molecular mechanisms that establish, interpret and modulate the information potential of RNA beyond the combination of four canonical nucleotides. This has resulted in mapping various epitranscriptomes at high resolution and in cataloguing the effects caused by aberrant RNA modification circuitry. While the scope of the obtained insights has been complex and exciting, most of current epitranscriptomics appears to be stuck in the process of producing data, with very few efforts to disentangle cause from consequence when studying a specific RNA modification system. This article discusses various knowledge gaps in this field with the aim to raise one specific question: how are the enzymes regulated that dynamically install and modify RNA modifications? Furthermore, various technologies will be highlighted whose development and use might allow identifying specific and context-dependent regulators of epitranscriptomic mechanisms. Given the complexity of individual epitranscriptomes, determining their regulatory principles will become crucially important, especially when aiming at modifying specific aspects of an epitranscriptome both for experimental and, potentially, therapeutic purposes.
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Affiliation(s)
- Matthias R Schaefer
- Centre for Anatomy & Cell Biology, Division of Cell-and Developmental Biology, Medical University of Vienna, Schwarzspanierstrasse 17, Haus C, 1st Floor, 1090 Vienna, Austria
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38
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Muñoz-Gómez SA, Bilolikar G, Wideman JG, Geiler-Samerotte K. Constructive Neutral Evolution 20 Years Later. J Mol Evol 2021; 89:172-182. [PMID: 33604782 PMCID: PMC7982386 DOI: 10.1007/s00239-021-09996-y] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2020] [Accepted: 01/13/2021] [Indexed: 12/29/2022]
Abstract
Evolution has led to a great diversity that ranges from elegant simplicity to ornate complexity. Many complex features are often assumed to be more functional or adaptive than their simpler alternatives. However, in 1999, Arlin Stolzfus published a paper in the Journal of Molecular Evolution that outlined a framework in which complexity can arise through a series of non-adaptive steps. He called this framework Constructive Neutral Evolution (CNE). Despite its two-decade-old roots, many evolutionary biologists still appear to be unaware of this explanatory framework for the origins of complexity. In this perspective piece, we explain the theory of CNE and how it changes the order of events in narratives that describe the evolution of complexity. We also provide an extensive list of cellular features that may have become more complex through CNE. We end by discussing strategies to determine whether complexity arose through neutral or adaptive processes.
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Affiliation(s)
- Sergio A Muñoz-Gómez
- School of Life Sciences, Biodesign Center for Mechanisms of Evolution, Arizona State University, Tempe, AZ, USA.
| | - Gaurav Bilolikar
- School of Life Sciences, Biodesign Center for Mechanisms of Evolution, Arizona State University, Tempe, AZ, USA
| | - Jeremy G Wideman
- School of Life Sciences, Biodesign Center for Mechanisms of Evolution, Arizona State University, Tempe, AZ, USA
| | - Kerry Geiler-Samerotte
- School of Life Sciences, Biodesign Center for Mechanisms of Evolution, Arizona State University, Tempe, AZ, USA.
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Gao Y, Liu H, Zhang C, Su S, Chen Y, Chen X, Li Y, Shao Z, Zhang Y, Shao Q, Li J, Huang Z, Ma J, Gan J. Structural basis for guide RNA trimming by RNase D ribonuclease in Trypanosoma brucei. Nucleic Acids Res 2021; 49:568-583. [PMID: 33332555 PMCID: PMC7797062 DOI: 10.1093/nar/gkaa1197] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2020] [Accepted: 11/24/2020] [Indexed: 11/18/2022] Open
Abstract
Infection with kinetoplastid parasites, including Trypanosoma brucei (T. brucei), Trypanosoma cruzi (T. cruzi) and Leishmania can cause serious disease in humans. Like other kinetoplastid species, mRNAs of these disease-causing parasites must undergo posttranscriptional editing in order to be functional. mRNA editing is directed by gRNAs, a large group of small RNAs. Similar to mRNAs, gRNAs are also precisely regulated. In T. brucei, overexpression of RNase D ribonuclease (TbRND) leads to substantial reduction in the total gRNA population and subsequent inhibition of mRNA editing. However, the mechanisms regulating gRNA binding and cleavage by TbRND are not well defined. Here, we report a thorough structural study of TbRND. Besides Apo- and NMP-bound structures, we also solved one TbRND structure in complexed with single-stranded RNA. In combination with mutagenesis and in vitro cleavage assays, our structures indicated that TbRND follows the conserved two-cation-assisted mechanism in catalysis. TbRND is a unique RND member, as it contains a ZFD domain at its C-terminus. In addition to T. brucei, our studies also advanced our understanding on the potential gRNA degradation pathway in T. cruzi, Leishmania, as well for as other disease-associated parasites expressing ZFD-containing RNDs.
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Affiliation(s)
- Yanqing Gao
- Shanghai Public Health Clinical Center, State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, Department of Physiology and Biophysics, School of Life Sciences, Fudan University, Shanghai 200438, China
| | - Hehua Liu
- Shanghai Public Health Clinical Center, State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, Department of Physiology and Biophysics, School of Life Sciences, Fudan University, Shanghai 200438, China
- State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, Department of Biochemistry, School of Life Sciences, Fudan University, Shanghai 200438, China
| | - Chong Zhang
- College of Life Sciences, Sichuan University, Chengdu 610041, China
| | - Shichen Su
- State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, Department of Biochemistry, School of Life Sciences, Fudan University, Shanghai 200438, China
| | - Yiqing Chen
- Shanghai Public Health Clinical Center, State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, Department of Physiology and Biophysics, School of Life Sciences, Fudan University, Shanghai 200438, China
| | - Xi Chen
- Shanghai Public Health Clinical Center, State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, Department of Physiology and Biophysics, School of Life Sciences, Fudan University, Shanghai 200438, China
- State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, Department of Biochemistry, School of Life Sciences, Fudan University, Shanghai 200438, China
| | - Yangyang Li
- Shanghai Public Health Clinical Center, State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, Department of Physiology and Biophysics, School of Life Sciences, Fudan University, Shanghai 200438, China
| | - Zhiwei Shao
- Shanghai Public Health Clinical Center, State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, Department of Physiology and Biophysics, School of Life Sciences, Fudan University, Shanghai 200438, China
| | - Yixi Zhang
- Shanghai Public Health Clinical Center, State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, Department of Physiology and Biophysics, School of Life Sciences, Fudan University, Shanghai 200438, China
| | - Qiyuan Shao
- Shanghai Public Health Clinical Center, State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, Department of Physiology and Biophysics, School of Life Sciences, Fudan University, Shanghai 200438, China
| | - Jixi Li
- Shanghai Public Health Clinical Center, State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, Department of Physiology and Biophysics, School of Life Sciences, Fudan University, Shanghai 200438, China
| | - Zhen Huang
- College of Life Sciences, Sichuan University, Chengdu 610041, China
| | - Jinbiao Ma
- State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, Department of Biochemistry, School of Life Sciences, Fudan University, Shanghai 200438, China
| | - Jianhua Gan
- Shanghai Public Health Clinical Center, State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, Department of Physiology and Biophysics, School of Life Sciences, Fudan University, Shanghai 200438, China
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40
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Aphasizheva I, Yu T, Suematsu T, Liu Q, Mesitov MV, Yu C, Huang L, Zhang L, Aphasizhev R. Poly(A) binding KPAF4/5 complex stabilizes kinetoplast mRNAs in Trypanosoma brucei. Nucleic Acids Res 2020; 48:8645-8662. [PMID: 32614436 PMCID: PMC7470953 DOI: 10.1093/nar/gkaa575] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2020] [Revised: 06/22/2020] [Accepted: 06/24/2020] [Indexed: 12/23/2022] Open
Abstract
In Trypanosoma brucei, mitochondrial pre-mRNAs undergo 3′-5′ exonucleolytic processing, 3′ adenylation and uridylation, 5′ pyrophosphate removal, and, often, U-insertion/deletion editing. The 3′ modifications are modulated by pentatricopeptide repeat (PPR) Kinetoplast Polyadenylation Factors (KPAFs). We have shown that KPAF3 binding to the 3′ region stabilizes properly trimmed transcripts and stimulates their A-tailing by KPAP1 poly(A) polymerase. Conversely, poly(A) binding KPAF4 shields the nascent A-tail from uridylation and decay thereby protecting pre-mRNA upon KPAF3 displacement by editing. While editing concludes in the 5′ region, KPAF1/2 dimer induces A/U-tailing to activate translation. Remarkably, 5′ end recognition and pyrophosphate hydrolysis by the PPsome complex also contribute to mRNA stabilization. Here, we demonstrate that KPAF4 functions as a heterodimer with KPAF5, a protein lacking discernable motifs. We show that KPAF5 stabilizes KPAF4 to enable poly(A) tail recognition, which likely leads to mRNA stabilization during the editing process and impedes spontaneous translational activation of partially-edited transcripts. Thus, KPAF4/5 represents a poly(A) binding element of the mitochondrial polyadenylation complex. We present evidence that RNA editing substrate binding complex bridges the 5′ end-bound PPsome and 3′ end-bound polyadenylation complexes. This interaction may enable mRNA circularization, an apparently critical element of mitochondrial mRNA stability and quality control.
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Affiliation(s)
- Inna Aphasizheva
- Department of Molecular and Cell Biology, Boston University Medical Campus, Boston, MA 02118, USA
| | - Tian Yu
- Department of Molecular and Cell Biology, Boston University Medical Campus, Boston, MA 02118, USA
| | - Takuma Suematsu
- Department of Molecular and Cell Biology, Boston University Medical Campus, Boston, MA 02118, USA
| | - Qiushi Liu
- Department of Molecular and Cell Biology, Boston University Medical Campus, Boston, MA 02118, USA
| | - Mikhail V Mesitov
- Department of Molecular and Cell Biology, Boston University Medical Campus, Boston, MA 02118, USA
| | - Clinton Yu
- Department of Physiology and Biophysics, School of Medicine, University of California, Irvine, CA 92697, USA
| | - Lan Huang
- Department of Physiology and Biophysics, School of Medicine, University of California, Irvine, CA 92697, USA
| | - Liye Zhang
- School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China
| | - Ruslan Aphasizhev
- Department of Molecular and Cell Biology, Boston University Medical Campus, Boston, MA 02118, USA.,Department of Biochemistry, Boston University Medical Campus, Boston, MA 02118, USA
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Baudouin HCM, Pfeiffer L, Ochsenreiter T. A comparison of three approaches for the discovery of novel tripartite attachment complex proteins in Trypanosoma brucei. PLoS Negl Trop Dis 2020; 14:e0008568. [PMID: 32936798 PMCID: PMC7521757 DOI: 10.1371/journal.pntd.0008568] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Revised: 09/28/2020] [Accepted: 07/07/2020] [Indexed: 11/19/2022] Open
Abstract
Trypanosoma brucei is a single celled eukaryotic parasite and the causative agent of human African trypanosomiasis and nagana in cattle. Aside from its medical relevance, T. brucei has also been key to the discovery of several general biological principles including GPI-anchoring, RNA-editing and trans-splicing. The parasite contains a single mitochondrion with a singular genome. Recent studies have identified several molecular components of the mitochondrial genome segregation machinery (tripartite attachment complex, TAC), which connects the basal body of the flagellum to the mitochondrial DNA of T. brucei. The TAC component in closest proximity to the mitochondrial DNA is TAC102. Here we apply and compare three different approaches (proximity labelling, immunoprecipitation and yeast two-hybrid) to identify novel interactors of TAC102 and subsequently verify their localisation. Furthermore, we establish the direct interaction of TAC102 and p166 in the unilateral filaments of the TAC. Trypanosoma brucei belongs to a group of organisms that exist as human, animal and plant parasites. T. brucei (a human and animal parasite) has been developed as a model system to study basic biological as well as disease related questions in this group of organisms. We study how the parasite duplicates and divides its mitochondrial genome, an essential component of its energy generating machinery. The structure involved in dividing the mitochondrial genome into the daughter cells during cell division is called the tripartite attachment complex (TAC). The TAC is likely a unique structure not present in the host and thus might provide a new avenue for drug development. In this manuscript, we compare different techniques that allow the identification of novel components of this structure and verify the localisation of some of them. Furthermore, we also establish the interaction of two previously identified protein components.
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Affiliation(s)
- Hélène Clémentine Margareta Baudouin
- Institute of Cell Biology, University of Bern, Bern, Switzerland
- Graduate School for Cellular and Biomedical Sciences, University of Bern, Bern, Switzerland
| | - Laura Pfeiffer
- Institute of Cell Biology, University of Bern, Bern, Switzerland
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Smith Jr. JT, Doleželová E, Tylec B, Bard JE, Chen R, Sun Y, Zíková A, Read LK. Developmental regulation of edited CYb and COIII mitochondrial mRNAs is achieved by distinct mechanisms in Trypanosoma brucei. Nucleic Acids Res 2020; 48:8704-8723. [PMID: 32738044 PMCID: PMC7470970 DOI: 10.1093/nar/gkaa641] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Revised: 07/16/2020] [Accepted: 07/21/2020] [Indexed: 01/01/2023] Open
Abstract
Trypanosoma brucei is a parasitic protozoan that undergoes a complex life cycle involving insect and mammalian hosts that present dramatically different nutritional environments. Mitochondrial metabolism and gene expression are highly regulated to accommodate these environmental changes, including regulation of mRNAs that require extensive uridine insertion/deletion (U-indel) editing for their maturation. Here, we use high throughput sequencing and a method for promoting life cycle changes in vitro to assess the mechanisms and timing of developmentally regulated edited mRNA expression. We show that edited CYb mRNA is downregulated in mammalian bloodstream forms (BSF) at the level of editing initiation and/or edited mRNA stability. In contrast, edited COIII mRNAs are depleted in BSF by inhibition of editing progression. We identify cell line-specific differences in the mechanisms abrogating COIII mRNA editing, including the possible utilization of terminator gRNAs that preclude the 3' to 5' progression of editing. By examining the developmental timing of altered mitochondrial mRNA levels, we also reveal transcript-specific developmental checkpoints in epimastigote (EMF), metacyclic (MCF), and BSF. These studies represent the first analysis of the mechanisms governing edited mRNA levels during T. brucei development and the first to interrogate U-indel editing in EMF and MCF life cycle stages.
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Affiliation(s)
- Joseph T Smith Jr.
- Department of Microbiology and Immunology, University at Buffalo – Jacobs School of Medicine and Biomedical Sciences, Buffalo, NY 14203, USA
| | - Eva Doleželová
- Institute of Parasitology, Biology Centre Czech Academy of Science, České Budejovice, Czech Republic
| | - Brianna Tylec
- Department of Microbiology and Immunology, University at Buffalo – Jacobs School of Medicine and Biomedical Sciences, Buffalo, NY 14203, USA
| | - Jonathan E Bard
- Genomics and Bioinformatics Core, University at Buffalo, Buffalo, NY 14203, USA
| | - Runpu Chen
- Department of Computer Science and Engineering, University at Buffalo, Buffalo, NY 14260, USA
| | - Yijun Sun
- Department of Microbiology and Immunology, University at Buffalo – Jacobs School of Medicine and Biomedical Sciences, Buffalo, NY 14203, USA
| | - Alena Zíková
- Institute of Parasitology, Biology Centre Czech Academy of Science, České Budejovice, Czech Republic
| | - Laurie K Read
- Department of Microbiology and Immunology, University at Buffalo – Jacobs School of Medicine and Biomedical Sciences, Buffalo, NY 14203, USA
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43
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Hammond MJ, Nenarokova A, Butenko A, Zoltner M, Dobáková EL, Field MC, Lukeš J. A Uniquely Complex Mitochondrial Proteome from Euglena gracilis. Mol Biol Evol 2020; 37:2173-2191. [PMID: 32159766 PMCID: PMC7403612 DOI: 10.1093/molbev/msaa061] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Euglena gracilis is a metabolically flexible, photosynthetic, and adaptable free-living protist of considerable environmental importance and biotechnological value. By label-free liquid chromatography tandem mass spectrometry, a total of 1,786 proteins were identified from the E. gracilis purified mitochondria, representing one of the largest mitochondrial proteomes so far described. Despite this apparent complexity, protein machinery responsible for the extensive RNA editing, splicing, and processing in the sister clades diplonemids and kinetoplastids is absent. This strongly suggests that the complex mechanisms of mitochondrial gene expression in diplonemids and kinetoplastids occurred late in euglenozoan evolution, arising independently. By contrast, the alternative oxidase pathway and numerous ribosomal subunits presumed to be specific for parasitic trypanosomes are present in E. gracilis. We investigated the evolution of unexplored protein families, including import complexes, cristae formation proteins, and translation termination factors, as well as canonical and unique metabolic pathways. We additionally compare this mitoproteome with the transcriptome of Eutreptiella gymnastica, illuminating conserved features of Euglenida mitochondria as well as those exclusive to E. gracilis. This is the first mitochondrial proteome of a free-living protist from the Excavata and one of few available for protists as a whole. This study alters our views of the evolution of the mitochondrion and indicates early emergence of complexity within euglenozoan mitochondria, independent of parasitism.
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Affiliation(s)
- Michael J Hammond
- Biology Centre, Institute of Parasitology, Czech Academy of Sciences, České Budějovice, Budweis, Czech Republic
| | - Anna Nenarokova
- Biology Centre, Institute of Parasitology, Czech Academy of Sciences, České Budějovice, Budweis, Czech Republic
- Faculty of Sciences, University of South Bohemia, České Budějovice, Budweis, Czech Republic
| | - Anzhelika Butenko
- Biology Centre, Institute of Parasitology, Czech Academy of Sciences, České Budějovice, Budweis, Czech Republic
- Faculty of Science, University of Ostrava, Ostrava, Czech Republic
| | - Martin Zoltner
- School of Life Sciences, University of Dundee, Dundee, United Kingdom
- Faculty of Science, Charles University, Biocev, Vestec, Czech Republic
| | - Eva Lacová Dobáková
- Biology Centre, Institute of Parasitology, Czech Academy of Sciences, České Budějovice, Budweis, Czech Republic
| | - Mark C Field
- Biology Centre, Institute of Parasitology, Czech Academy of Sciences, České Budějovice, Budweis, Czech Republic
- School of Life Sciences, University of Dundee, Dundee, United Kingdom
| | - Julius Lukeš
- Biology Centre, Institute of Parasitology, Czech Academy of Sciences, České Budějovice, Budweis, Czech Republic
- Faculty of Sciences, University of South Bohemia, České Budějovice, Budweis, Czech Republic
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Mehta V, Moshiri H, Srikanth A, Kala S, Lukeš J, Salavati R. Sulfonated inhibitors of the RNA editing ligases validate the essential role of the MRP1/2 proteins in kinetoplastid RNA editing. RNA (NEW YORK, N.Y.) 2020; 26:827-835. [PMID: 32276989 PMCID: PMC7297121 DOI: 10.1261/rna.075598.120] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2020] [Accepted: 04/06/2020] [Indexed: 05/21/2023]
Abstract
The RNA editing core complex (RECC) catalyzes mitochondrial U-insertion/deletion mRNA editing in trypanosomatid flagellates. Some naphthalene-based sulfonated compounds, such as C35 and MrB, competitively inhibit the auto-adenylylation activity of an essential RECC enzyme, kinetoplastid RNA editing ligase 1 (KREL1), required for the final step in editing. Previous studies revealed the ability of these compounds to interfere with the interaction between the editosome and its RNA substrates, consequently affecting all catalytic activities that comprise RNA editing. This observation implicates a critical function for the affected RNA binding proteins in RNA editing. In this study, using the inhibitory compounds, we analyzed the composition and editing activities of functional editosomes and identified the mitochondrial RNA binding proteins 1 and 2 (MRP1/2) as their preferred targets. While the MRP1/2 heterotetramer complex is known to bind guide RNA and promote annealing to its cognate pre-edited mRNA, its role in RNA editing remained enigmatic. We show that the compounds affect the association between the RECC and MRP1/2 heterotetramer. Furthermore, RECC purified post-treatment with these compounds exhibit compromised in vitro RNA editing activity that, remarkably, recovers upon the addition of recombinant MRP1/2 proteins. This work provides experimental evidence that the MRP1/2 heterotetramer is required for in vitro RNA editing activity and substantiates the hypothesized role of these proteins in presenting the RNA duplex to the catalytic complex in the initial steps of RNA editing.
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Affiliation(s)
- Vaibhav Mehta
- Department of Biochemistry, McGill University, Montreal, H3G1Y6 Quebec, Canada
- Institute of Parasitology, McGill University, Ste. Anne de Bellevue, H9X 3V9 Quebec, Canada
| | - Houtan Moshiri
- Department of Biochemistry, McGill University, Montreal, H3G1Y6 Quebec, Canada
- Institute of Parasitology, McGill University, Ste. Anne de Bellevue, H9X 3V9 Quebec, Canada
| | - Akshaya Srikanth
- Institute of Parasitology, McGill University, Ste. Anne de Bellevue, H9X 3V9 Quebec, Canada
| | - Smriti Kala
- Institute of Parasitology, McGill University, Ste. Anne de Bellevue, H9X 3V9 Quebec, Canada
| | - Julius Lukeš
- Institute of Parasitology, Biology Centre and Faculty of Science, University of South Bohemia, 37005 České Budějovice (Budweis), Czech Republic
| | - Reza Salavati
- Department of Biochemistry, McGill University, Montreal, H3G1Y6 Quebec, Canada
- Institute of Parasitology, McGill University, Ste. Anne de Bellevue, H9X 3V9 Quebec, Canada
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45
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Pyrih J, Rašková V, Škodová-Sveráková I, Pánek T, Lukeš J. ZapE/Afg1 interacts with Oxa1 and its depletion causes a multifaceted phenotype. PLoS One 2020; 15:e0234918. [PMID: 32579605 PMCID: PMC7314023 DOI: 10.1371/journal.pone.0234918] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2020] [Accepted: 06/04/2020] [Indexed: 11/19/2022] Open
Abstract
ZapE/Afg1 is a component of the inner cell membrane of some eubacteria and the inner mitochondrial membrane of eukaryotes. This protein is involved in FtsZ-dependent division of eubacteria. In the yeast and human mitochondrion, ZapE/Afg1 likely interacts with Oxa1 and facilitates the degradation of mitochondrion-encoded subunits of respiratory complexes. Furthermore, the depletion of ZapE increases resistance to apoptosis, decreases oxidative stress tolerance, and impacts mitochondrial protein homeostasis. It remains unclear whether ZapE is a multifunctional protein, or whether some of the described effects are just secondary phenotypes. Here, we have analyzed the functions of ZapE in Trypanosoma brucei, a parasitic protist, and an important model organism. Using a newly developed proximity-dependent biotinylation approach (BioID2), we have identified the inner mitochondrial membrane insertase Oxa1 among three putative interacting partners of ZapE, which is present in two paralogs. RNAi-mediated depletion of both ZapE paralogs likely affected the function of respiratory complexes I and IV. Consistently, we show that the distribution of mitochondrial ZapE is restricted only to organisms with Oxa1, respiratory complexes, and a mitochondrial genome. We propose that the evolutionarily conserved interaction of ZapE with Oxa1, which is required for proper insertion of many inner mitochondrial membrane proteins, is behind the multifaceted phenotype caused by the ablation of ZapE.
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Affiliation(s)
- Jan Pyrih
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, České Budějovice (Budweis), Czech Republic
- * E-mail: (JL); (JP)
| | - Vendula Rašková
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, České Budějovice (Budweis), Czech Republic
- Faculty of Science, University of South Bohemia, České Budějovice (Budweis), Czech Republic
| | - Ingrid Škodová-Sveráková
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, České Budějovice (Budweis), Czech Republic
- Faculty of Sciences, Comenius University, Bratislava, Slovakia
| | - Tomáš Pánek
- Faculty of Sciences, University of Ostrava, Ostrava, Czech Republic
| | - Julius Lukeš
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, České Budějovice (Budweis), Czech Republic
- Faculty of Science, University of South Bohemia, České Budějovice (Budweis), Czech Republic
- * E-mail: (JL); (JP)
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46
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Miller JC, Delzell SB, Concepción-Acevedo J, Boucher MJ, Klingbeil MM. A DNA polymerization-independent role for mitochondrial DNA polymerase I-like protein C in African trypanosomes. J Cell Sci 2020; 133:jcs.233072. [PMID: 32079654 DOI: 10.1242/jcs.233072] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2019] [Accepted: 02/10/2020] [Indexed: 01/01/2023] Open
Abstract
Mitochondrial DNA of Trypanosoma brucei and related parasites is a catenated network containing thousands of minicircles and tens of maxicircles, called kinetoplast DNA (kDNA). Replication of a single nucleoid requires at least three DNA polymerase I-like proteins (i.e. POLIB, POLIC and POLID), each showing discrete localizations near the kDNA during S phase. POLIB and POLID have roles in minicircle replication but the specific role of POLIC in kDNA maintenance is less clear. Here, we use an RNA interference (RNAi)-complementation system to dissect the functions of two distinct POLIC regions, i.e. the conserved family A DNA polymerase (POLA) domain and the uncharacterized N-terminal region (UCR). While RNAi complementation with wild-type POLIC restored kDNA content and cell cycle localization of kDNA, active site point mutations in the POLA domain impaired minicircle replication similar to that of POLIB and POLID depletions. Complementation with POLA domain alone abolished the formation of POLIC foci and partially rescued the RNAi phenotype. Furthermore, we provide evidence that the UCR is crucial in cell cycle-dependent protein localization and facilitates proper distribution of progeny networks. This is the first report of a DNA polymerase that impacts on mitochondrial nucleoid distribution.This article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
- Jonathan C Miller
- Department of Microbiology, University of Massachusetts, Amherst, MA 01003, USA
| | - Stephanie B Delzell
- Department of Microbiology, University of Massachusetts, Amherst, MA 01003, USA
| | - Jeniffer Concepción-Acevedo
- Centers for Disease Control and Prevention, National Center for Emerging and Zoonotic Infectious Diseases, 1600 Clifton Road, Atlanta, GA 30329, USA
| | - Michael J Boucher
- Department of Biochemistry and Biophysics, University of California San Francisco, San Francisco, CA 94158, USA
| | - Michele M Klingbeil
- Department of Microbiology, University of Massachusetts, Amherst, MA 01003, USA .,Division of Foodborne,Waterborne, and Environmental Diseases, The Institute of Applied Life Sciences, University of Massachusetts, Amherst, MA 01003, USA
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47
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Rajan KS, Zhu Y, Adler K, Doniger T, Cohen-Chalamish S, Srivastava A, Shalev-Benami M, Matzov D, Unger R, Tschudi C, Günzl A, Carmichael GG, Michaeli S. The large repertoire of 2'-O-methylation guided by C/D snoRNAs on Trypanosoma brucei rRNA. RNA Biol 2020; 17:1018-1039. [PMID: 32250712 DOI: 10.1080/15476286.2020.1750842] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The parasite Trypanosoma brucei cycles between insect and mammalian hosts, and is the causative agent of sleeping sickness. Here, we performed genome-wide mapping of 2'-O-methylations (Nms) on trypanosome rRNA using three high-throughput sequencing methods; RibOxi-seq, RiboMeth-seq and 2'-OMe-seq. This is the first study using three genome-wide mapping approaches on rRNA from the same species showing the discrepancy among the methods. RibOxi-seq detects all the sites, but RiboMeth-seq is the only method to evaluate the level of a single Nm site. The sequencing revealed at least ninety-nine Nms guided by eighty-five snoRNAs among these thirty-eight Nms are trypanosome specific sites. We present the sequence and target of the C/D snoRNAs guiding on rRNA. This is the highest number of Nms detected to date on rRNA of a single cell parasite. Based on RiboMeth-seq, several Nm sites were found to be differentially regulated at the two stages of the parasite life cycle, the insect procyclic form (PCF) versus the bloodstream form (BSF) in the mammalian host.
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Affiliation(s)
- K Shanmugha Rajan
- The Mina and Everard Goodman Faculty of Life Sciences and Advanced Materials and Nanotechnology Institute, Bar-Ilan University , Ramat-Gan, Israel
| | - Yinzhou Zhu
- Department of Genetics and Genome Sciences, UConn Health , Farmington, CT, USA
| | - Katerina Adler
- The Mina and Everard Goodman Faculty of Life Sciences and Advanced Materials and Nanotechnology Institute, Bar-Ilan University , Ramat-Gan, Israel
| | - Tirza Doniger
- The Mina and Everard Goodman Faculty of Life Sciences and Advanced Materials and Nanotechnology Institute, Bar-Ilan University , Ramat-Gan, Israel
| | - Smadar Cohen-Chalamish
- The Mina and Everard Goodman Faculty of Life Sciences and Advanced Materials and Nanotechnology Institute, Bar-Ilan University , Ramat-Gan, Israel
| | - Ankita Srivastava
- Department of Genetics and Genome Sciences, UConn Health , Farmington, CT, USA
| | - Moran Shalev-Benami
- Department of Structural Biology, Weizmann Institute of Science , Rehovot, Israel
| | - Donna Matzov
- Department of Structural Biology, Weizmann Institute of Science , Rehovot, Israel
| | - Ron Unger
- The Mina and Everard Goodman Faculty of Life Sciences and Advanced Materials and Nanotechnology Institute, Bar-Ilan University , Ramat-Gan, Israel
| | - Christian Tschudi
- Departmentof Epidemiology and Microbial Diseases, Yale School of Public Health , New Haven, CT, USA
| | - Arthur Günzl
- Department of Genetics and Genome Sciences, UConn Health , Farmington, CT, USA
| | - Gordon G Carmichael
- Department of Genetics and Genome Sciences, UConn Health , Farmington, CT, USA
| | - Shulamit Michaeli
- The Mina and Everard Goodman Faculty of Life Sciences and Advanced Materials and Nanotechnology Institute, Bar-Ilan University , Ramat-Gan, Israel
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48
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Aphasizheva I, Alfonzo J, Carnes J, Cestari I, Cruz-Reyes J, Göringer HU, Hajduk S, Lukeš J, Madison-Antenucci S, Maslov DA, McDermott SM, Ochsenreiter T, Read LK, Salavati R, Schnaufer A, Schneider A, Simpson L, Stuart K, Yurchenko V, Zhou ZH, Zíková A, Zhang L, Zimmer S, Aphasizhev R. Lexis and Grammar of Mitochondrial RNA Processing in Trypanosomes. Trends Parasitol 2020; 36:337-355. [PMID: 32191849 PMCID: PMC7083771 DOI: 10.1016/j.pt.2020.01.006] [Citation(s) in RCA: 60] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2019] [Revised: 01/19/2020] [Accepted: 01/22/2020] [Indexed: 12/15/2022]
Abstract
Trypanosoma brucei spp. cause African human and animal trypanosomiasis, a burden on health and economy in Africa. These hemoflagellates are distinguished by a kinetoplast nucleoid containing mitochondrial DNAs of two kinds: maxicircles encoding ribosomal RNAs (rRNAs) and proteins and minicircles bearing guide RNAs (gRNAs) for mRNA editing. All RNAs are produced by a phage-type RNA polymerase as 3' extended precursors, which undergo exonucleolytic trimming. Most pre-mRNAs proceed through 3' adenylation, uridine insertion/deletion editing, and 3' A/U-tailing. The rRNAs and gRNAs are 3' uridylated. Historically, RNA editing has attracted major research effort, and recently essential pre- and postediting processing events have been discovered. Here, we classify the key players that transform primary transcripts into mature molecules and regulate their function and turnover.
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Affiliation(s)
- Inna Aphasizheva
- Department of Molecular and Cell Biology, Boston University Medical Campus, Boston, MA 02118, USA.
| | - Juan Alfonzo
- Department of Microbiology, The Ohio State University, Columbus, OH 43210, USA
| | - Jason Carnes
- Center for Global Infectious Disease Research, Seattle Children's Research Institute, Seattle, WA 98109, USA
| | - Igor Cestari
- Institute of Parasitology, McGill University, 21,111 Lakeshore Road, Ste-Anne-de-Bellevue, H9X3V9, Québec, Canada
| | - Jorge Cruz-Reyes
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843, USA
| | - H Ulrich Göringer
- Department of Molecular Genetics, Darmstadt University of Technology, 64287 Darmstadt, Germany
| | - Stephen Hajduk
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602, USA
| | - Julius Lukeš
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences and Faculty of Sciences, University of South Bohemia, České Budějovice (Budweis), Czech Republic
| | - Susan Madison-Antenucci
- Parasitology Laboratory, Wadsworth Center, New York State Department of Health, Albany, NY 12201, USA
| | - Dmitri A Maslov
- Department of Molecular, Cell, and Systems Biology, University of California - Riverside, Riverside, CA 92521, USA
| | - Suzanne M McDermott
- Center for Global Infectious Disease Research, Seattle Children's Research Institute, Seattle, WA 98109, USA
| | - Torsten Ochsenreiter
- Institute of Cell Biology, University of Bern, Baltzerstrasse 4, Bern CH-3012, Switzerland
| | - Laurie K Read
- Department of Microbiology and Immunology, University at Buffalo, Jacobs School of Medicine and Biomedical Sciences, Buffalo, NY 14203, USA
| | - Reza Salavati
- Institute of Parasitology, McGill University, 21,111 Lakeshore Road, Ste-Anne-de-Bellevue, H9X3V9, Québec, Canada
| | - Achim Schnaufer
- Institute of Immunology and Infection Research, University of Edinburgh, Edinburgh EH9 3FL, UK
| | - André Schneider
- Department of Chemistry and Biochemistry, University of Bern, Bern CH-3012, Switzerland
| | - Larry Simpson
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, CA90095, USA
| | - Kenneth Stuart
- Center for Global Infectious Disease Research, Seattle Children's Research Institute, Seattle, WA 98109, USA
| | - Vyacheslav Yurchenko
- Life Science Research Centre, Faculty of Science, University of Ostrava, Ostrava, Czech Republic; Martsinovsky Institute of Medical Parasitology, Sechenov University, Moscow, Russia
| | - Z Hong Zhou
- Department of Microbiology, Immunology and Molecular Genetics, University of California, Los Angeles, CA90095, USA
| | - Alena Zíková
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences and Faculty of Sciences, University of South Bohemia, České Budějovice (Budweis), Czech Republic
| | - Liye Zhang
- School of Life Science and Technology, ShanghaiTech University, Shanghai, 201210, China
| | - Sara Zimmer
- University of Minnesota Medical School, Duluth campus, Duluth, MN 55812, USA
| | - Ruslan Aphasizhev
- Department of Molecular and Cell Biology, Boston University Medical Campus, Boston, MA 02118, USA
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49
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Kirby LE, Koslowsky D. Cell-line specific RNA editing patterns in Trypanosoma brucei suggest a unique mechanism to generate protein variation in a system intolerant to genetic mutations. Nucleic Acids Res 2020; 48:1479-1493. [PMID: 31840176 PMCID: PMC7026638 DOI: 10.1093/nar/gkz1131] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Revised: 11/11/2019] [Accepted: 12/12/2019] [Indexed: 12/19/2022] Open
Abstract
Trypanosoma brucei possesses a highly complex RNA editing system that uses guide RNAs to direct the insertion and deletion of uridines in mitochondrial mRNAs. These changes extensively alter the target mRNAs and can more than double them in length. Recently, analyses showed that several of the edited genes possess the capacity to encode two different protein products. The overlapped reading frames can be accessed through alternative RNA editing that shifts the translated reading frame. In this study, we analyzed the editing patterns of three putative dual-coding genes, ribosomal protein S12 (RPS12), the 5′ editing domain of NADH dehydrogenase subunit 7 (ND7 5′), and C-rich region 3 (CR3). We found evidence that alternatively 5′-edited ND7 5′ and CR3 transcripts are present in the transcriptome, providing evidence for the use of dual ORFs in these transcripts. Moreover, we found that CR3 has a complex set of editing pathways that vary substantially between cell lines. These findings suggest that alternative editing can work to introduce genetic variation in a system that selects against nucleotide mutations.
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Affiliation(s)
- Laura E Kirby
- Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI 48824, USA
| | - Donna Koslowsky
- Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI 48824, USA
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50
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Koeller CM, Tiengwe C, Schwartz KJ, Bangs JD. Steric constraints control processing of glycosylphosphatidylinositol anchors in Trypanosoma brucei. J Biol Chem 2020; 295:2227-2238. [PMID: 31932305 DOI: 10.1074/jbc.ra119.010847] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2019] [Revised: 12/26/2019] [Indexed: 11/06/2022] Open
Abstract
The transferrin receptor (TfR) of the bloodstream form (BSF) of Trypanosoma brucei is a heterodimer comprising glycosylphosphatidylinositol (GPI)-anchored expression site-associated gene 6 (ESAG6 or E6) and soluble ESAG7. Mature E6 has five N-glycans, consisting of three oligomannose and two unprocessed paucimannose structures. Its GPI anchor is modified by the addition of 4-6 α-galactose residues. TfR binds tomato lectin (TL), specific for N-acetyllactosamine (LacNAc) repeats, and previous studies have shown transport-dependent increases in E6 size consistent with post-glycan processing in the endoplasmic reticulum. Using pulse-chase radiolabeling, peptide-N-glycosidase F treatment, lectin pulldowns, and exoglycosidase treatment, we have now investigated TfR N-glycan and GPI processing. E6 increased ∼5 kDa during maturation, becoming reactive with both TL and Erythrina cristagalli lectin (ECL, terminal LacNAc), indicating synthesis of poly-LacNAc on paucimannose N-glycans. This processing was lost after exoglycosidase treatment and after RNAi-based silencing of TbSTT3A, the oligosaccharyltransferase that transfers paucimannose structures to nascent secretory polypeptides. These results contradict previous structural studies. Minor GPI processing was also observed, consistent with α-galactose addition. However, increasing the spacing between E6 protein and the GPI ω-site (aa 4-7) resulted in extensive post-translational processing of the GPI anchor to a form that was TL/ECL-reactive, suggesting the addition of LacNAc structures, confirmed by identical assays with BiPNHP, a non-N-glycosylated GPI-anchored reporter. We conclude that BSF trypanosomes can modify GPIs by generating structures reminiscent of those present in insect-stage trypanosomes and that steric constraints, not stage-specific expression of glycosyltransferases, regulate GPI processing.
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Affiliation(s)
- Carolina M Koeller
- Department of Microbiology and Immunology, School of Medicine and Biomedical Sciences, University at Buffalo (SUNY), Buffalo, New York 14214
| | - Calvin Tiengwe
- Department of Microbiology and Immunology, School of Medicine and Biomedical Sciences, University at Buffalo (SUNY), Buffalo, New York 14214
| | - Kevin J Schwartz
- Department of Medical Microbiology and Immunology, University of Wisconsin, Madison, Wisconsin, 53706
| | - James D Bangs
- Department of Microbiology and Immunology, School of Medicine and Biomedical Sciences, University at Buffalo (SUNY), Buffalo, New York 14214.
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