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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Wackowski K, Zhu X, Shen S, Zhang M, Qu J, Read LK. RESC14 and RESC8 cooperate to mediate RESC function and dynamics during trypanosome RNA editing. Nucleic Acids Res 2024:gkae561. [PMID: 38967000 DOI: 10.1093/nar/gkae561] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2023] [Revised: 05/16/2024] [Accepted: 06/18/2024] [Indexed: 07/06/2024] Open
Abstract
Mitochondrial transcripts in Trypanosoma brucei require extensive uridine insertion/deletion RNA editing to generate translatable open reading frames. The RNA editing substrate binding complex (RESC) serves as the scaffold that coordinates the protein-protein and protein-RNA interactions during editing. RESC broadly contains two modules termed the guide RNA binding complex (GRBC) and the RNA editing mediator complex (REMC), as well as organizer proteins. How the protein and RNA components of RESC dynamically interact to facilitate editing is not well understood. Here, we examine the roles of organizer proteins, RESC8 and RESC14, in facilitating RESC dynamics. High-throughput sequencing of editing intermediates reveals an overlapping RESC8 and RESC14 function during editing progression across multiple transcripts. Blue native PAGE analysis demonstrates that RESC14 is essential for incorporation of RESC8 into a large RNA-containing complex, while RESC8 is important in recruiting a smaller ribonucleoprotein complex (RNP) to this large complex. Proximity labeling shows that RESC14 is important for stable RESC protein-protein interactions, as well as RESC-RECC associations. Together, our data support a model in which RESC14 is necessary for assembly of editing competent RESC through recruitment of an RNP containing RESC8, GRBC and gRNA to REMC and mRNA.
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Affiliation(s)
- Katherine Wackowski
- Department of Microbiology and Immunology, Jacobs School of Medicine and Biomedical Sciences, Buffalo, NY 14203, USA
| | - Xiaoyu Zhu
- Department of Pharmaceutical Sciences, University at Buffalo, Buffalo, NY 14214, USA and NYS Center of Excellence in Bioinformatics and Life Sciences, University at Buffalo, Buffalo, NY 14203, USA
| | - Shichen Shen
- Department of Pharmaceutical Sciences, University at Buffalo, Buffalo, NY 14214, USA and NYS Center of Excellence in Bioinformatics and Life Sciences, University at Buffalo, Buffalo, NY 14203, USA
| | - Ming Zhang
- Department of Pharmaceutical Sciences, University at Buffalo, Buffalo, NY 14214, USA and NYS Center of Excellence in Bioinformatics and Life Sciences, University at Buffalo, Buffalo, NY 14203, USA
| | - Jun Qu
- Department of Pharmaceutical Sciences, University at Buffalo, Buffalo, NY 14214, USA and NYS Center of Excellence in Bioinformatics and Life Sciences, University at Buffalo, Buffalo, NY 14203, USA
| | - Laurie K Read
- Department of Microbiology and Immunology, Jacobs School of Medicine and Biomedical Sciences, Buffalo, NY 14203, USA
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3
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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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4
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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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5
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Mitochondrial RNA editing in Trypanoplasma borreli: new tools, new revelations. Comput Struct Biotechnol J 2022; 20:6388-6402. [DOI: 10.1016/j.csbj.2022.11.023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Revised: 11/09/2022] [Accepted: 11/09/2022] [Indexed: 11/16/2022] Open
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6
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Sortino K, Tylec BL, Chen R, Sun Y, Read LK. Conserved and transcript-specific functions of the RESC factors, RESC13 and RESC14, in kinetoplastid RNA editing. RNA (NEW YORK, N.Y.) 2022; 28:1496-1508. [PMID: 36096641 PMCID: PMC9745829 DOI: 10.1261/rna.079389.122] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2022] [Accepted: 08/28/2022] [Indexed: 05/21/2023]
Abstract
Uridine insertion/deletion RNA editing is an extensive post-transcriptional modification of mitochondrial mRNAs in kinetoplastid organisms, including Trypanosoma brucei This process is carried out using trans-acting gRNAs and complex protein machinery. The essential RNA editing substrate binding complex (RESC) serves as the scaffold that modulates protein and RNA interactions during editing, and contains the guide RNA binding complex (GRBC), the RNA editing mediator complexes (REMCs), and organizer proteins. Despite the importance of RESC in editing, the functions of each protein comprising this complex are not completely understood. Here, we further define the roles of a REMC protein, RESC13, and a RESC organizer, RESC14, using high-throughput sequencing on two large pan-edited mRNAs, A6 and COIII. When comparing our analyses to that of a previously published small pan-edited mRNA, RPS12, we find that RESC13 has conserved functions across the three transcripts with regard to editing initiation, gRNA utilization, gRNA exchange, and restricting the formation of long misedited junctions that likely arise from its ability to modulate RNA structure. However, RESC13 does have transcript-specific effects on the types of long junctions whose formation it restricts. RESC14 has a conserved effect on gRNA utilization across the three transcripts analyzed, but has transcript-specific effects on editing initiation, gRNA exchange, and junction formation. Our data suggest that transcript-specific effects of both proteins are due to differences in transcript length and sequences as well as transcript-specific protein interactions. These findings highlight the importance of studying multiple transcripts to determine the function of editing factors.
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Affiliation(s)
- Katherine Sortino
- Department of Microbiology and Immunology, University at Buffalo, Jacobs School of Medicine and Biomedical Sciences, Buffalo, New York 14203, USA
| | - Brianna L Tylec
- Department of Microbiology and Immunology, University at Buffalo, Jacobs School of Medicine and Biomedical Sciences, Buffalo, New York 14203, USA
| | - Runpu Chen
- Department of Microbiology and Immunology, University at Buffalo, Jacobs School of Medicine and Biomedical Sciences, Buffalo, New York 14203, USA
| | - Yijun Sun
- Department of Microbiology and Immunology, University at Buffalo, Jacobs School of Medicine and Biomedical Sciences, Buffalo, New York 14203, USA
| | - Laurie K Read
- Department of Microbiology and Immunology, University at Buffalo, Jacobs School of Medicine and Biomedical Sciences, Buffalo, New York 14203, USA
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7
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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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8
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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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9
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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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10
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Kramer S, Meyer-Natus E, Stigloher C, Thoma H, Schnaufer A, Engstler M. Parallel monitoring of RNA abundance, localization and compactness with correlative single molecule FISH on LR White embedded samples. Nucleic Acids Res 2021; 49:e14. [PMID: 33275141 PMCID: PMC7897490 DOI: 10.1093/nar/gkaa1142] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2020] [Revised: 10/16/2020] [Accepted: 11/17/2020] [Indexed: 01/19/2023] Open
Abstract
Single mRNA molecules are frequently detected by single molecule fluorescence in situ hybridization (smFISH) using branched DNA technology. While providing strong and background-reduced signals, the method is inefficient in detecting mRNAs within dense structures, in monitoring mRNA compactness and in quantifying abundant mRNAs. To overcome these limitations, we have hybridized slices of high pressure frozen, freeze-substituted and LR White embedded cells (LR White smFISH). mRNA detection is physically restricted to the surface of the resin. This enables single molecule detection of RNAs with accuracy comparable to RNA sequencing, irrespective of their abundance, while at the same time providing spatial information on RNA localization that can be complemented with immunofluorescence and electron microscopy, as well as array tomography. Moreover, LR White embedding restricts the number of available probe pair recognition sites for each mRNA to a small subset. As a consequence, differences in signal intensities between RNA populations reflect differences in RNA structures, and we show that the method can be employed to determine mRNA compactness. We apply the method to answer some outstanding questions related to trans-splicing, RNA granules and mitochondrial RNA editing in single-cellular trypanosomes and we show an example of differential gene expression in the metazoan Caenorhabditis elegans.
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Affiliation(s)
- Susanne Kramer
- Zell- und Entwicklungsbiologie, Biozentrum, Universität Würzburg, Würzburg, Germany
| | | | - Christian Stigloher
- Zell- und Entwicklungsbiologie, Biozentrum, Universität Würzburg, Würzburg, Germany.,Imaging Core Facility, Biozentrum, Universität Würzburg, Würzburg, Germany
| | - Hanna Thoma
- Zell- und Entwicklungsbiologie, Biozentrum, Universität Würzburg, Würzburg, Germany
| | - Achim Schnaufer
- Institute for Immunology & Infection Research, University of Edinburgh, Edinburgh, UK
| | - Markus Engstler
- Zell- und Entwicklungsbiologie, Biozentrum, Universität Würzburg, Würzburg, Germany
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11
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Kumar V, Ivens A, Goodall Z, Meehan J, Doharey PK, Hillhouse A, Hurtado DO, Cai JJ, Zhang X, Schnaufer A, Cruz-Reyes J. Site-specific and substrate-specific control of accurate mRNA editing by a helicase complex in trypanosomes. RNA (NEW YORK, N.Y.) 2020; 26:1862-1881. [PMID: 32873716 PMCID: PMC7668249 DOI: 10.1261/rna.076513.120] [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: 05/31/2020] [Accepted: 08/22/2020] [Indexed: 05/21/2023]
Abstract
Trypanosome U-insertion/deletion RNA editing in mitochondrial mRNAs involves guide RNAs (gRNAs) and the auxiliary RNA editing substrate binding complex (RESC) and RNA editing helicase 2 complex (REH2C). RESC and REH2C stably copurify with editing mRNAs but the functional interplay between these complexes remains unclear. Most steady-state mRNAs are partially edited and include misedited "junction" regions that match neither pre-mRNA nor fully edited transcripts. Editing specificity is central to mitochondrial RNA maturation and function, but its basic control mechanisms remain unclear. Here we applied a novel nucleotide-resolution RNA-seq approach to examine ribosomal protein subunit 12 (RPS12) and ATPase subunit 6 (A6) mRNA transcripts. We directly compared transcripts associated with RESC and REH2C to those found in total mitochondrial RNA. RESC-associated transcripts exhibited site-preferential enrichments in total and accurate edits. REH2C loss-of-function induced similar substrate-specific and site-specific editing effects in total and RESC-associated RNA. It decreased total editing primarily at RPS12 5' positions but increased total editing at examined A6 3' positions. REH2C loss-of-function caused site-preferential loss of accurate editing in both transcripts. However, changes in total or accurate edits did not necessarily involve common sites. A few 5' nucleotides of the initiating gRNA (gRNA-1) directed accurate editing in both transcripts. However, in RPS12, two conserved 3'-terminal adenines in gRNA-1 could direct a noncanonical 2U-insertion that causes major pausing in 3'-5' progression. In A6, a noncanonical sequence element that depends on REH2C in a region normally targeted by the 3' half of gRNA-1 may hinder early editing progression. Overall, we defined transcript-specific effects of REH2C loss.
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Affiliation(s)
- Vikas Kumar
- Department of Biochemistry, Texas A&M University, College Station, Texas 77843, USA
| | - Alasdair Ivens
- Institute of Immunology and Infection Research, University of Edinburgh, Edinburgh EH9 3FL, Scotland, United Kingdom
| | - Zachary Goodall
- Department of Biochemistry, Texas A&M University, College Station, Texas 77843, USA
| | - Joshua Meehan
- Department of Biochemistry, Texas A&M University, College Station, Texas 77843, USA
| | - Pawan Kumar Doharey
- Department of Biochemistry, Texas A&M University, College Station, Texas 77843, USA
| | - Andrew Hillhouse
- Texas A&M Institute for Genome Sciences and Society, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, Texas 77843, USA
| | - Daniel Osorio Hurtado
- Department of Veterinary Integrative Biosciences, Texas A&M University, College Station, Texas 77843, USA
| | - James J Cai
- Department of Veterinary Integrative Biosciences, Texas A&M University, College Station, Texas 77843, USA
| | - Xiuren Zhang
- Department of Biochemistry, Texas A&M University, College Station, Texas 77843, USA
| | - Achim Schnaufer
- Institute of Immunology and Infection Research, University of Edinburgh, Edinburgh EH9 3FL, Scotland, United Kingdom
| | - Jorge Cruz-Reyes
- Department of Biochemistry, Texas A&M University, College Station, Texas 77843, USA
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12
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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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13
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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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14
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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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15
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Cooper S, Wadsworth ES, Ochsenreiter T, Ivens A, Savill NJ, Schnaufer A. Assembly and annotation of the mitochondrial minicircle genome of a differentiation-competent strain of Trypanosoma brucei. Nucleic Acids Res 2019; 47:11304-11325. [PMID: 31665448 PMCID: PMC6868439 DOI: 10.1093/nar/gkz928] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2019] [Revised: 10/03/2019] [Accepted: 10/08/2019] [Indexed: 01/10/2023] Open
Abstract
Kinetoplastids are protists defined by one of the most complex mitochondrial genomes in nature, the kinetoplast. In the sleeping sickness parasite Trypanosoma brucei, the kinetoplast is a chain mail-like network of two types of interlocked DNA molecules: a few dozen ∼23-kb maxicircles (homologs of the mitochondrial genome of other eukaryotes) and thousands of ∼1-kb minicircles. Maxicircles encode components of respiratory chain complexes and the mitoribosome. Several maxicircle-encoded mRNAs undergo extensive post-transcriptional RNA editing via addition and deletion of uridines. The process is mediated by hundreds of species of minicircle-encoded guide RNAs (gRNAs), but the precise number of minicircle classes and gRNA genes was unknown. Here we present the first essentially complete assembly and annotation of the kinetoplast genome of T. brucei. We have identified 391 minicircles, encoding not only ∼930 predicted 'canonical' gRNA genes that cover nearly all known editing events (accessible via the web at http://hank.bio.ed.ac.uk), but also ∼370 'non-canonical' gRNA genes of unknown function. Small RNA transcriptome data confirmed expression of the majority of both categories of gRNAs. Finally, we have used our data set to refine definitions for minicircle structure and to explore dynamics of minicircle copy numbers.
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Affiliation(s)
- Sinclair Cooper
- Institute of Immunology & Infection Research, University of Edinburgh, Edinburgh, Scotland EH9 3FL, UK
| | - Elizabeth S Wadsworth
- Institute of Immunology & Infection Research, University of Edinburgh, Edinburgh, Scotland EH9 3FL, UK
| | | | - Alasdair Ivens
- Institute of Immunology & Infection Research, University of Edinburgh, Edinburgh, Scotland EH9 3FL, UK
| | - Nicholas J Savill
- Institute of Immunology & Infection Research, University of Edinburgh, Edinburgh, Scotland EH9 3FL, UK
| | - Achim Schnaufer
- Institute of Immunology & Infection Research, University of Edinburgh, Edinburgh, Scotland EH9 3FL, UK
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16
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McAdams NM, Harrison GL, Tylec BL, Ammerman ML, Chen R, Sun Y, Read LK. MRB10130 is a RESC assembly factor that promotes kinetoplastid RNA editing initiation and progression. RNA (NEW YORK, N.Y.) 2019; 25:1177-1191. [PMID: 31221726 PMCID: PMC6800514 DOI: 10.1261/rna.071902.119] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2019] [Accepted: 06/18/2019] [Indexed: 05/03/2023]
Abstract
Uridine insertion deletion editing in kinetoplastid protozoa requires a complex machinery, a primary component of which is the RNA editing substrate binding complex (RESC). RESC contains two modules termed GRBC (guide RNA binding complex) and REMC (RNA editing mediator complex), although how interactions between these modules and their mRNA and gRNA binding partners are controlled is not well understood. Here, we demonstrate that the ARM/HEAT repeat containing RESC protein, MRB10130, controls REMC association with mRNA- and gRNA-loaded GRBC. High-throughput sequencing analyses show that MRB10130 functions in both initiation and 3' to 5' progression of editing through gRNA-defined domains. Editing intermediates that accumulate upon MRB10130 depletion significantly intersect those in cells depleted of another RESC organizer, MRB7260, but are distinct from those in cells depleted of specific REMC proteins. We present a model in which MRB10130 coordinates numerous protein-protein and protein-RNA interactions during editing progression.
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Affiliation(s)
- Natalie M McAdams
- Department of Microbiology and Immunology, University at Buffalo Jacobs School of Medicine and Biomedical Sciences, Buffalo, New York 14203, USA
| | - Gregory L Harrison
- Department of Microbiology and Immunology, University at Buffalo Jacobs School of Medicine and Biomedical Sciences, Buffalo, New York 14203, USA
| | - Brianna L Tylec
- Department of Microbiology and Immunology, University at Buffalo Jacobs School of Medicine and Biomedical Sciences, Buffalo, New York 14203, USA
| | - Michelle L Ammerman
- Department of Chemistry and Biochemistry, Kettering University, Flint, Michigan 48504, USA
| | - Runpu Chen
- Department of Computer Science and Engineering, University at Buffalo, Buffalo, New York 14260, USA
| | - Yijun Sun
- Department of Microbiology and Immunology, University at Buffalo Jacobs School of Medicine and Biomedical Sciences, Buffalo, New York 14203, USA
| | - Laurie K Read
- Department of Microbiology and Immunology, University at Buffalo Jacobs School of Medicine and Biomedical Sciences, Buffalo, New York 14203, USA
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17
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Gerasimov ES, Gasparyan AA, Kaurov I, Tichý B, Logacheva MD, Kolesnikov AA, Lukeš J, Yurchenko V, Zimmer SL, Flegontov P. Trypanosomatid mitochondrial RNA editing: dramatically complex transcript repertoires revealed with a dedicated mapping tool. Nucleic Acids Res 2019; 46:765-781. [PMID: 29220521 PMCID: PMC5778460 DOI: 10.1093/nar/gkx1202] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2017] [Accepted: 11/20/2017] [Indexed: 12/22/2022] Open
Abstract
RNA editing by targeted insertion and deletion of uridine is crucial to generate translatable mRNAs from the cryptogenes of the mitochondrial genome of kinetoplastids. This type of editing consists of a stepwise cascade of reactions generally proceeding from 3′ to 5′ on a transcript, resulting in a population of partially edited as well as pre-edited and completely edited molecules for each mitochondrial cryptogene of these protozoans. Often, the number of uridines inserted and deleted exceed the number of nucleotides that are genome-encoded. Thus, analysis of kinetoplastid mitochondrial transcriptomes has proven frustratingly complex. Here we present our analysis of Leptomonas pyrrhocoris mitochondrial cDNA deep sequencing reads using T-Aligner, our new tool which allows comprehensive characterization of RNA editing, not relying on targeted transcript amplification and on prior knowledge of final edited products. T-Aligner implements a pipeline of read mapping, visualization of all editing states and their coverage, and assembly of canonical and alternative translatable mRNAs. We also assess T-Aligner functionality on a more challenging deep sequencing read input from Trypanosoma cruzi. The analysis reveals that transcripts of cryptogenes of both species undergo very complex editing that includes the formation of alternative open reading frames and whole categories of truncated editing products.
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Affiliation(s)
- Evgeny S Gerasimov
- Faculty of Biology, M.V. Lomonosov Moscow State University, Moscow 119991, 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
| | - Iosif Kaurov
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, České Budějovice 370 05, Czech Republic.,Faculty of Science, University of South Bohemia, České Budějovice 370 05, Czech Republic
| | - Boris Tichý
- Central European Institute of Technology, Masaryk University, Brno 625 00, Czech Republic
| | - Maria D Logacheva
- Belozersky Institute of Physico-Chemical Biology, M.V. Lomonosov Moscow State University, Moscow 119991, Russia.,Russia Extreme Biology Laboratory, Institute of Fundamental Medicine and Biology, Kazan Federal University, Kazan, 420008, Russia.,Skolkovo Institute of Science and Technology, Moscow, 14326, Russia
| | | | - Julius Lukeš
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, České Budějovice 370 05, Czech Republic.,Faculty of Science, University of South Bohemia, České Budějovice 370 05, Czech Republic
| | - Vyacheslav Yurchenko
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, České Budějovice 370 05, Czech Republic.,Life Science Research Centre, Faculty of Science, University of Ostrava, Ostrava 710 00, Czech Republic.,Institute of Environmental Technologies, Faculty of Science, University of Ostrava, Ostrava 710 00, Czech Republic
| | - Sara L Zimmer
- Department of Biomedical Sciences, University of Minnesota Medical School, Duluth, MN 55812-3031, USA
| | - Pavel Flegontov
- Institute of Parasitology, Biology Centre, Czech Academy of Sciences, České Budějovice 370 05, Czech Republic.,Belozersky Institute of Physico-Chemical Biology, M.V. Lomonosov Moscow State University, Moscow 119991, Russia.,Life Science Research Centre, Faculty of Science, University of Ostrava, Ostrava 710 00, Czech Republic
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18
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Maslov DA. Separating the Wheat from the Chaff: RNA Editing and Selection of Translatable mRNA in Trypanosome Mitochondria. Pathogens 2019; 8:E105. [PMID: 31323762 PMCID: PMC6789859 DOI: 10.3390/pathogens8030105] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Revised: 07/14/2019] [Accepted: 07/16/2019] [Indexed: 11/16/2022] Open
Abstract
In the mitochondria of trypanosomes and related kinetoplastid protists, most mRNAs undergo a long and sophisticated maturation pathway before they can be productively translated by mitochondrial ribosomes. Some of the aspects of this pathway (identity of the promotors, transcription initiation, and termination signals) remain obscure, and some (post-transcriptional modification by U-insertion/deletion, RNA editing, 3'-end maturation) have been illuminated by research during the last decades. The RNA editing creates an open reading frame for a productive translation, but the fully edited mRNA often represents a minor fraction in the pool of pre-edited and partially edited precursors. Therefore, it has been expected that the final stages of the mRNA processing generate molecular hallmarks, which allow for the efficient and selective recognition of translation-competent templates. The general contours and several important details of this process have become known only recently and represent the subject of this review.
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Affiliation(s)
- Dmitri A Maslov
- Department of Molecular, Cell and Systems Biology, University of California, Riverside, CA 92521, USA.
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19
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Kumar V, Doharey PK, Gulati S, Meehan J, Martinez MG, Hughes K, Mooers BHM, Cruz-Reyes J. Protein features for assembly of the RNA editing helicase 2 subcomplex (REH2C) in Trypanosome holo-editosomes. PLoS One 2019; 14:e0211525. [PMID: 31034523 PMCID: PMC6488192 DOI: 10.1371/journal.pone.0211525] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2019] [Accepted: 04/11/2019] [Indexed: 02/06/2023] Open
Abstract
Uridylate insertion/deletion RNA editing in Trypanosoma brucei is a complex system that is not found in humans, so there is interest in targeting this system for drug development. This system uses hundreds of small non-coding guide RNAs (gRNAs) to modify the mitochondrial mRNA transcriptome. This process occurs in holo-editosomes that assemble several macromolecular trans factors around mRNA including the RNA-free RNA editing core complex (RECC) and auxiliary ribonucleoprotein (RNP) complexes. Yet, the regulatory mechanisms of editing remain obscure. The enzymatic accessory RNP complex, termed the REH2C, includes mRNA substrates and products, the multi-domain 240 kDa RNA Editing Helicase 2 (REH2) and an intriguing 8-zinc finger protein termed REH2-Associated Factor 1 (H2F1). Both of these proteins are essential in editing. REH2 is a member of the DExH/RHA subfamily of RNA helicases with a conserved C-terminus that includes a regulatory OB-fold domain. In trypanosomes, H2F1 recruits REH2 to the editing apparatus, and H2F1 downregulation causes REH2 fragmentation. Our systematic mutagenesis dissected determinants in REH2 and H2F1 for the assembly of REH2C, the stability of REH2, and the RNA-mediated association of REH2C with other editing trans factors. We identified functional OB-fold amino acids in eukaryotic DExH/RHA helicases that are conserved in REH2 and that impact the assembly and interactions of REH2C. H2F1 upregulation stabilized REH2 in vivo. Mutation of the core cysteines or basic amino acids in individual zinc fingers affected the stabilizing property of H2F1 but not its interactions with other examined editing components. This result suggests that most, if not all, fingers may contribute to REH2 stabilization. Finally, a recombinant REH2 (240 kDa) established that the full-length protein is a bona fide RNA helicase with ATP-dependent unwinding activity. REH2 is the only DExH/RHA-type helicase in kinetoplastid holo-editosomes.
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Affiliation(s)
- Vikas Kumar
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas, United States of America
| | - Pawan K. Doharey
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas, United States of America
| | - Shelly Gulati
- Department of Biochemistry & Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, United States of America
| | - Joshua Meehan
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas, United States of America
| | - Mary G. Martinez
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas, United States of America
| | - Karrisa Hughes
- Department of Biochemistry & Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, United States of America
| | - Blaine H. M. Mooers
- Department of Biochemistry & Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, United States of America
- * E-mail: (JC); (BM)
| | - Jorge Cruz-Reyes
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas, United States of America
- * E-mail: (JC); (BM)
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20
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Tylec BL, Simpson RM, Kirby LE, Chen R, Sun Y, Koslowsky DJ, Read LK. Intrinsic and regulated properties of minimally edited trypanosome mRNAs. Nucleic Acids Res 2019; 47:3640-3657. [PMID: 30698753 PMCID: PMC6468165 DOI: 10.1093/nar/gkz012] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2018] [Revised: 01/02/2019] [Accepted: 01/08/2019] [Indexed: 12/17/2022] Open
Abstract
Most mitochondrial mRNAs in kinetoplastids require extensive uridine insertion/deletion editing to generate translatable open reading frames. Editing is specified by trans-acting gRNAs and involves a complex machinery including basal and accessory factors. Here, we utilize high-throughput sequencing to analyze editing progression in two minimally edited mRNAs that provide a simplified system due their requiring only two gRNAs each for complete editing. We show that CYb and MURF2 mRNAs exhibit barriers to editing progression that differ from those previously identified for pan-edited mRNAs, primarily at initial gRNA usage and gRNA exchange. We demonstrate that mis-edited junctions arise through multiple pathways including mis-alignment of cognate gRNA, incorrect and sometimes promiscuous gRNA utilization and inefficient gRNA anchoring. We then examined the roles of accessory factors RBP16 and MRP1/2 in maintaining edited CYb and MURF2 populations. RBP16 is essential for initiation of CYb and MURF2 editing, as well as MURF2 editing progression. In contrast, MRP1/2 stabilizes both edited mRNA populations, while further promoting progression of MURF2 mRNA editing. We also analyzed the effects of RNA Editing Substrate Binding Complex components, TbRGG2 and GAP1, and show that both proteins modestly impact progression of editing on minimally edited mRNAs, suggesting a novel function for GAP1.
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Affiliation(s)
- Brianna L Tylec
- Department of Microbiology and Immunology, University at Buffalo Jacobs School of Medicine and Biomedical Sciences, Buffalo, NY 14203
| | - Rachel M Simpson
- Department of Microbiology and Immunology, University at Buffalo Jacobs School of Medicine and Biomedical Sciences, Buffalo, NY 14203
| | - Laura E Kirby
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI 48824
| | - Runpu Chen
- Department of Computer Science and Engineering, University at Buffalo, Buffalo, NY 14260
| | - Yijun Sun
- Department of Microbiology and Immunology, University at Buffalo Jacobs School of Medicine and Biomedical Sciences, Buffalo, NY 14203
| | - Donna J Koslowsky
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, MI 48824
| | - Laurie K Read
- Department of Microbiology and Immunology, University at Buffalo Jacobs School of Medicine and Biomedical Sciences, Buffalo, NY 14203
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21
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Dixit S, Lukeš J. Combinatorial interplay of RNA-binding proteins tunes levels of mitochondrial mRNA in trypanosomes. RNA (NEW YORK, N.Y.) 2018; 24:1594-1606. [PMID: 30120147 PMCID: PMC6191715 DOI: 10.1261/rna.066233.118] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2018] [Accepted: 08/10/2018] [Indexed: 05/11/2023]
Abstract
MRP1/2 is a heteromeric protein complex that functions in the trypanosomatid mitochondrion as part of the RNA editing machinery, which facilitates multiple targeted insertions and deletions of uridines. MRP1/2 was shown to interact with MRB8170, which initiates RNA editing by marking pre-edited mRNAs, while TbRGG2 is required for its efficient progression on pan-edited mRNAs. Both MRP1/2 and TbRGG2 are capable of modulating RNA-RNA interactions in vitro. As determined by using iCLIP and RIP-qPCR, RNAs bound to MRP1/2 are characterized and compared with those associated with MRB8170 and TbRGG2. We provide evidence that MRP1 and MRB8170 have correlated binding and similar RNA crosslinking peak profiles over minimally and never-edited mRNAs. Our results suggest that MRP1 assists MRB8170 in RNA editing on minimally edited mRNAs.
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Affiliation(s)
- Sameer Dixit
- Institute of Parasitology, Biology Center, Czech Academy of Sciences and Faculty of Sciences, University of South Bohemia, 37005 České Budějovice (Budweis), Czech Republic
| | - Julius Lukeš
- Institute of Parasitology, Biology Center, Czech Academy of Sciences and Faculty of Sciences, University of South Bohemia, 37005 České Budějovice (Budweis), Czech Republic
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22
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Liu J, Jiang H, Zan J, Bao Y, Dong J, Xiong L, Nie L. Single-molecule long-read transcriptome profiling of Platysternon megacephalum mitochondrial genome with gene rearrangement and control region duplication. RNA Biol 2018; 15:1244-1249. [PMID: 30200821 DOI: 10.1080/15476286.2018.1521212] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022] Open
Abstract
Platysternon megacephalum is the sole living representative of the poorly studied turtle lineage Platysternidae. Their mitochondrial genome has been subject to gene rearrangement and control region duplication, resulting in a unique mitochondrial gene order in vertebrates. In this study, we sequenced the first full-length turtle (P. megacephalum) liver transcriptome using single-molecule real-time sequencing to study the transcriptional mechanisms of its mitochondrial genome. ND5 and ND6 anti-sense (ND6AS) forms a single transcript with the same expression in the human mitochondrial genome, but here we demonstrated differential expression of the rearranged ND5 and ND6AS genes in P. megacephalum. And some polycistronic transcripts were also reported in this study. Notably, we detected some novel long non-coding RNAs with alternative polyadenylation from the duplicated control region, and a novel ND6AS transcript composed of a long non-coding sequence, ND6AS, and tRNA-GluAS. These results provide the first description of a mtDNA transcriptome with gene rearrangement and control region duplication. These findings further our understanding of the fundamental concepts of mitochondrial gene transcription and RNA processing, and provide a new insight into the mechanism of transcription regulation of the mitochondrial genome.
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Affiliation(s)
- Jianjun Liu
- a Provincial Key Laboratory of the Conservation and Exploitation Research of Biological Resources in Anhui , Life Science College of Anhui Normal University , Wuhu , Anhui , P.R. China
| | - Hui Jiang
- a Provincial Key Laboratory of the Conservation and Exploitation Research of Biological Resources in Anhui , Life Science College of Anhui Normal University , Wuhu , Anhui , P.R. China
| | - Jiawei Zan
- a Provincial Key Laboratory of the Conservation and Exploitation Research of Biological Resources in Anhui , Life Science College of Anhui Normal University , Wuhu , Anhui , P.R. China
| | - Yuantian Bao
- a Provincial Key Laboratory of the Conservation and Exploitation Research of Biological Resources in Anhui , Life Science College of Anhui Normal University , Wuhu , Anhui , P.R. China
| | - Jinxiu Dong
- a Provincial Key Laboratory of the Conservation and Exploitation Research of Biological Resources in Anhui , Life Science College of Anhui Normal University , Wuhu , Anhui , P.R. China
| | - Lei Xiong
- a Provincial Key Laboratory of the Conservation and Exploitation Research of Biological Resources in Anhui , Life Science College of Anhui Normal University , Wuhu , Anhui , P.R. China
| | - Liuwang Nie
- a Provincial Key Laboratory of the Conservation and Exploitation Research of Biological Resources in Anhui , Life Science College of Anhui Normal University , Wuhu , Anhui , P.R. China
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23
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Cruz-Reyes J, Mooers BHM, Doharey PK, Meehan J, Gulati S. Dynamic RNA holo-editosomes with subcomplex variants: Insights into the control of trypanosome editing. WILEY INTERDISCIPLINARY REVIEWS-RNA 2018; 9:e1502. [PMID: 30101566 DOI: 10.1002/wrna.1502] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/21/2018] [Revised: 07/03/2018] [Accepted: 07/09/2018] [Indexed: 12/14/2022]
Abstract
RNA editing causes massive remodeling of the mitochondrial mRNA transcriptome in trypanosomes and related kinetoplastid protozoa. This type of editing involves the specific insertion or deletion of uridylates (U) directed by small noncoding guide RNAs (gRNAs). Because U-insertion exceeds U-deletion by a factor of 10, editing increases the nascent mRNA size by up to 55%. In Trypanosoma brucei, the editing apparatus uses ~40 proteins and >1,200 gRNAs to create the functional open reading frame in 12 mRNAs. Thousands of sites are specifically recognized in the pre-edited mRNAs and a myriad of partially edited transcript intermediates accumulates in mitochondria. The control of editing is poorly understood, but past work suggests that it occurs during substrate recognition, the initiation and progression of editing, and during the life-cycle in different hosts. The growing understanding of the editing proteins offers clues about editing control. Most editing proteins reside in the "RNA-free" RNA editing core complex (RECC) and in the accessory RNA editing substrate complex (RESC) that contains gRNA. Two accessory RNA helicases are known, including one in the RNA editing helicase 2 complex (REH2C). Both the RESC and the REH2C associate with mRNA, providing a rationale for the assembly of mRNA or its mRNPs, RESC, and the RECC enzyme. Identified variants of the canonical editing complexes further complicate the model of RNA editing. We examine specific examples of complex variants, differential effects of editing proteins on the mRNAs within and between T. brucei life stages, and possible control points in RNA holo-editosomes. This article is categorized under: RNA Processing > RNA Editing and Modification RNA Interactions with Proteins and Other Molecules > RNA-Protein Complexes RNA Interactions with Proteins and Other Molecules > Protein-RNA Interactions: Functional Implications.
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Affiliation(s)
- Jorge Cruz-Reyes
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas
| | - Blaine H M Mooers
- Department of Biochemistry & Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma
| | - Pawan K Doharey
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas
| | - Joshua Meehan
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas
| | - Shelly Gulati
- Department of Biochemistry & Molecular Biology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma
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24
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Abstract
Codon usage depends on mutation bias, tRNA-mediated selection, and the need for high efficiency and accuracy in translation. One codon in a synonymous codon family is often strongly over-used, especially in highly expressed genes, which often leads to a high dN/dS ratio because dS is very small. Many different codon usage indices have been proposed to measure codon usage and codon adaptation. Sense codon could be misread by release factors and stop codons misread by tRNAs, which also contribute to codon usage in rare cases. This chapter outlines the conceptual framework on codon evolution, illustrates codon-specific and gene-specific codon usage indices, and presents their applications. A new index for codon adaptation that accounts for background mutation bias (Index of Translation Elongation) is presented and contrasted with codon adaptation index (CAI) which does not consider background mutation bias. They are used to re-analyze data from a recent paper claiming that translation elongation efficiency matters little in protein production. The reanalysis disproves the claim.
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25
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Zimmer SL, Simpson RM, Read LK. High throughput sequencing revolution reveals conserved fundamentals of U-indel editing. WILEY INTERDISCIPLINARY REVIEWS-RNA 2018; 9:e1487. [PMID: 29888550 DOI: 10.1002/wrna.1487] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2018] [Revised: 04/26/2018] [Accepted: 04/30/2018] [Indexed: 01/18/2023]
Abstract
Among Euglenozoans, mitochondrial RNA editing occurs in the diplonemids and in the kinetoplastids that include parasitic trypanosomes. Yet U-indel editing, in which open reading frames (ORFs) on mRNAs are generated by insertion and deletion of uridylates in locations dictated by guide RNAs, appears confined to kinetoplastids. The nature of guide RNA and edited mRNA populations has been cursorily explored in a surprisingly extensive number of species over the years, although complete sets of fully edited mRNAs for most kinetoplast genomes are largely missing. Now, however, high throughput sequencing technologies have had an enormous impact on what we know and will learn about the mechanisms, benefits, and final edited products of U-indel editing. Tools including PARERS, TREAT, and T-Aligner function to organize and make sense of U-indel mRNA transcriptomes, which are comprised of mRNAs harboring uridylate indels both consistent and inconsistent with translatable products. From high throughput sequencing data come arguments that partially edited mRNAs containing "junction regions" of noncanonical editing are editing intermediates, and conversely, arguments that they are dead-end products. These data have also revealed that the percent of a given transcript population that is fully or partially edited varies dramatically between transcripts and organisms. Outstanding questions that are being addressed include the prevalence of sequences that apparently encode alternative ORFs, diversity of editing events in ORF termini and 5' and 3' untranslated regions, and the differences that exist in this byzantine process between species. High throughput sequencing technologies will also undoubtedly be harnessed to probe U-indel editing's evolutionary origins. This article is categorized under: RNA Processing > RNA Editing and Modification RNA Evolution and Genomics > Computational Analyses of RNA.
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Affiliation(s)
- Sara L Zimmer
- Department of Biomedical Sciences, University of Minnesota Medical School, Duluth, Minnesota
| | - Rachel M Simpson
- Department of Microbiology and Immunology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, New York
| | - Laurie K Read
- Department of Microbiology and Immunology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Buffalo, New York
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26
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Kalem MC, Gerasimov ES, Vu PK, Zimmer SL. Gene expression to mitochondrial metabolism: Variability among cultured Trypanosoma cruzi strains. PLoS One 2018; 13:e0197983. [PMID: 29847594 PMCID: PMC5976161 DOI: 10.1371/journal.pone.0197983] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2018] [Accepted: 05/11/2018] [Indexed: 11/18/2022] Open
Abstract
The insect-transmitted protozoan parasite Trypanosoma cruzi experiences changes in nutrient availability and rate of flux through different metabolic pathways across its life cycle. The species encompasses much genetic diversity of both the nuclear and mitochondrial genomes among isolated strains. The genetic or expression variation of both genomes are likely to impact metabolic responses to environmental stimuli, and even steady state metabolic function, among strains. To begin formal characterization these differences, we compared aspects of metabolism between genetically similar strains CL Brener and Tulahuen with less similar Esmeraldo and Sylvio X10 strains in a culture environment. Epimastigotes of all strains took up glucose at similar rates. However, the degree of medium acidification that could be observed when glucose was absent from the medium varied by strain, indicating potential differences in excreted metabolic byproducts. Our main focus was differences related to electron transport chain function. We observed differences in ATP-coupled respiration and maximal respiratory capacity, mitochondrial membrane potential, and mitochondrial morphology between strains, despite the fact that abundances of two nuclear-encoded proteins of the electron transport chain are similar between strains. RNA sequencing reveals strain-specific differences in abundances of mRNAs encoding proteins of the respiratory chain but also other metabolic processes. From these differences in metabolism and mitochondrial phenotypes we have generated tentative models for the differential metabolic fluxes or differences in gene expression that may underlie these results.
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Affiliation(s)
- Murat C. Kalem
- Department of Biology, University of Minnesota Duluth, Duluth, Minnesota, United States of America
- Department of Biomedical Sciences, University of Minnesota Medical School, Duluth campus, Duluth, Minnesota, United States of America
| | | | - Pamela K. Vu
- Department of Biology, University of Minnesota Duluth, Duluth, Minnesota, United States of America
| | - Sara L. Zimmer
- Department of Biomedical Sciences, University of Minnesota Medical School, Duluth campus, Duluth, Minnesota, United States of America
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27
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McAdams NM, Simpson RM, Chen R, Sun Y, Read LK. MRB7260 is essential for productive protein-RNA interactions within the RNA editing substrate binding complex during trypanosome RNA editing. RNA (NEW YORK, N.Y.) 2018; 24:540-556. [PMID: 29330168 PMCID: PMC5855954 DOI: 10.1261/rna.065169.117] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2017] [Accepted: 01/08/2018] [Indexed: 05/20/2023]
Abstract
The trypanosome RNA editing substrate binding complex (RESC) acts as the platform for mitochondrial uridine insertion/deletion RNA editing and facilitates the protein-protein and protein-RNA interactions required for the editing process. RESC is broadly comprised of two subcomplexes: GRBC (guide RNA binding complex) and REMC (RNA editing mediator complex). Here, we characterize the function and position in RESC organization of a previously unstudied RESC protein, MRB7260. We show that MRB7260 forms numerous RESC-related complexes, including a novel, small complex with the guide RNA binding protein, GAP1, which is a canonical GRBC component, and REMC components MRB8170 and TbRGG2. RNA immunoprecipitations in MRB7260-depleted cells show that MRB7260 is critical for normal RNA trafficking between REMC and GRBC. Analysis of protein-protein interactions also reveals an important role for MRB7260 in promoting stable association of the two subcomplexes. High-throughput sequencing analysis of RPS12 mRNAs from MRB7260 replete and depleted cells demonstrates that MRB7260 is critical for gRNA exchange and early gRNA utilization, with the exception of the initiating gRNA. Together, these data demonstrate that MRB7260 is essential for productive protein-RNA interactions with RESC during RNA editing.
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Affiliation(s)
- Natalie M McAdams
- Department of Microbiology and Immunology, University at Buffalo Jacobs School of Medicine and Biomedical Sciences, Buffalo, New York 14203, USA
| | - Rachel M Simpson
- Department of Microbiology and Immunology, University at Buffalo Jacobs School of Medicine and Biomedical Sciences, Buffalo, New York 14203, USA
| | - Runpu Chen
- Department of Computer Science and Engineering, University at Buffalo, Buffalo, New York 14260, USA
| | - Yijun Sun
- Department of Microbiology and Immunology, University at Buffalo Jacobs School of Medicine and Biomedical Sciences, Buffalo, New York 14203, USA
| | - Laurie K Read
- Department of Microbiology and Immunology, University at Buffalo Jacobs School of Medicine and Biomedical Sciences, Buffalo, New York 14203, USA
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28
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ARSDA: A New Approach for Storing, Transmitting and Analyzing Transcriptomic Data. G3-GENES GENOMES GENETICS 2017; 7:3839-3848. [PMID: 29079682 PMCID: PMC5714481 DOI: 10.1534/g3.117.300271] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Two major stumbling blocks exist in high-throughput sequencing (HTS) data analysis. The first is the sheer file size, typically in gigabytes when uncompressed, causing problems in storage, transmission, and analysis. However, these files do not need to be so large, and can be reduced without loss of information. Each HTS file, either in compressed .SRA or plain text .fastq format, contains numerous identical reads stored as separate entries. For example, among 44,603,541 forward reads in the SRR4011234.sra file (from a Bacillus subtilis transcriptomic study) deposited at NCBI’s SRA database, one read has 497,027 identical copies. Instead of storing them as separate entries, one can and should store them as a single entry with the SeqID_NumCopy format (which I dub as FASTA+ format). The second is the proper allocation of reads that map equally well to paralogous genes. I illustrate in detail a new method for such allocation. I have developed ARSDA software that implement these new approaches. A number of HTS files for model species are in the process of being processed and deposited at http://coevol.rdc.uottawa.ca to demonstrate that this approach not only saves a huge amount of storage space and transmission bandwidth, but also dramatically reduces time in downstream data analysis. Instead of matching the 497,027 identical reads separately against the B. subtilis genome, one only needs to match it once. ARSDA includes functions to take advantage of HTS data in the new sequence format for downstream data analysis such as gene expression characterization. I contrasted gene expression results between ARSDA and Cufflinks so readers can better appreciate the strength of ARSDA. ARSDA is freely available for Windows, Linux. and Macintosh computers at http://dambe.bio.uottawa.ca/ARSDA/ARSDA.aspx.
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29
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Simpson RM, Bruno AE, Chen R, Lott K, Tylec BL, Bard JE, Sun Y, Buck MJ, Read LK. Trypanosome RNA Editing Mediator Complex proteins have distinct functions in gRNA utilization. Nucleic Acids Res 2017; 45:7965-7983. [PMID: 28535252 PMCID: PMC5737529 DOI: 10.1093/nar/gkx458] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2017] [Revised: 05/01/2017] [Accepted: 05/10/2017] [Indexed: 11/13/2022] Open
Abstract
Uridine insertion/deletion RNA editing is an essential process in kinetoplastid parasites whereby mitochondrial mRNAs are modified through the specific insertion and deletion of uridines to generate functional open reading frames, many of which encode components of the mitochondrial respiratory chain. The roles of numerous non-enzymatic editing factors have remained opaque given the limitations of conventional methods to interrogate the order and mechanism by which editing progresses and thus roles of individual proteins. Here, we examined whole populations of partially edited sequences using high throughput sequencing and a novel bioinformatic platform, the Trypanosome RNA Editing Alignment Tool (TREAT), to elucidate the roles of three proteins in the RNA Editing Mediator Complex (REMC). We determined that the factors examined function in the progression of editing through a gRNA; however, they have distinct roles and REMC is likely heterogeneous in composition. We provide the first evidence that editing can proceed through numerous paths within a single gRNA and that non-linear modifications are essential, generating commonly observed junction regions. Our data support a model in which RNA editing is executed via multiple paths that necessitate successive re-modification of junction regions facilitated, in part, by the REMC variant containing TbRGG2 and MRB8180.
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Affiliation(s)
- Rachel M. Simpson
- Department of Microbiology and Immunology, University at Buffalo Jacobs School of Medicine and Biomedical Sciences, 3435 Main Street, Buffalo, NY 14214, USA
| | - Andrew E. Bruno
- Center for Computational Research, University at Buffalo, 701 Ellicott St., Buffalo, NY 14203, USA
| | - Runpu Chen
- Department of Computer Science and Engineering, New York State Center of Excellence in Bioinformatics and Life Sciences, 701 Ellicott St., Buffalo, NY 14203, USA
| | - Kaylen Lott
- Department of Microbiology and Immunology, University at Buffalo Jacobs School of Medicine and Biomedical Sciences, 3435 Main Street, Buffalo, NY 14214, USA
| | - Brianna L. Tylec
- Department of Microbiology and Immunology, University at Buffalo Jacobs School of Medicine and Biomedical Sciences, 3435 Main Street, Buffalo, NY 14214, USA
| | - Jonathan E. Bard
- Genomics and Bioinformatics Core, University at Buffalo, 701 Ellicott St., Buffalo, NY 14203, USA
| | - Yijun Sun
- Department of Microbiology and Immunology, University at Buffalo Jacobs School of Medicine and Biomedical Sciences, 3435 Main Street, Buffalo, NY 14214, USA
- Center for Computational Research, University at Buffalo, 701 Ellicott St., Buffalo, NY 14203, USA
| | - Michael J. Buck
- Department of Biochemistry, University at Buffalo Jacobs School of Medicine and Biomedical Sciences, 701 Ellicott St., Buffalo, NY 14203, USA
| | - Laurie K. Read
- Department of Microbiology and Immunology, University at Buffalo Jacobs School of Medicine and Biomedical Sciences, 3435 Main Street, Buffalo, NY 14214, USA
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Carnes J, McDermott S, Anupama A, Oliver BG, Sather DN, Stuart K. In vivo cleavage specificity of Trypanosoma brucei editosome endonucleases. Nucleic Acids Res 2017; 45:4667-4686. [PMID: 28334821 PMCID: PMC5416837 DOI: 10.1093/nar/gkx116] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2016] [Revised: 01/09/2017] [Accepted: 02/15/2017] [Indexed: 11/13/2022] Open
Abstract
RNA editing is an essential post-transcriptional process that creates functional mitochondrial mRNAs in Kinetoplastids. Multiprotein editosomes catalyze pre-mRNA cleavage, uridine (U) insertion or deletion, and ligation as specified by guide RNAs. Three functionally and compositionally distinct editosomes differ by the mutually exclusive presence of the KREN1, KREN2 or KREN3 endonuclease and their associated partner proteins. Because endonuclease cleavage is a likely point of regulation for RNA editing, we elucidated endonuclease specificity in vivo. We used a mutant gamma ATP synthase allele (MGA) to circumvent the normal essentiality of the editing endonucleases, and created cell lines in which both alleles of one, two or all three of the endonucleases were deleted. Cells lacking multiple endonucleases had altered editosome sedimentation on glycerol gradients and substantial defects in overall editing. Deep sequencing analysis of RNAs from such cells revealed clear discrimination by editosomes between sites of deletion versus insertion editing and preferential but overlapping specificity for sites of insertion editing. Thus, endonuclease specificities in vivo are distinct but with some functional overlap. The overlapping specificities likely accommodate the more numerous sites of insertion versus deletion editing as editosomes collaborate to accurately edit thousands of distinct editing sites in vivo.
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Affiliation(s)
- Jason Carnes
- Center for Infectious Disease Research (formerly Seattle BioMed), Seattle, WA 98109, USA
| | - Suzanne McDermott
- Center for Infectious Disease Research (formerly Seattle BioMed), Seattle, WA 98109, USA
| | - Atashi Anupama
- Center for Infectious Disease Research (formerly Seattle BioMed), Seattle, WA 98109, USA
| | - Brian G. Oliver
- Center for Infectious Disease Research (formerly Seattle BioMed), Seattle, WA 98109, USA
| | - D. Noah Sather
- Center for Infectious Disease Research (formerly Seattle BioMed), Seattle, WA 98109, USA
| | - Kenneth Stuart
- Center for Infectious Disease Research (formerly Seattle BioMed), Seattle, WA 98109, USA
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31
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Mitochondrial Gene Expression Is Responsive to Starvation Stress and Developmental Transition in Trypanosoma cruzi. mSphere 2016; 1:mSphere.00051-16. [PMID: 27303725 PMCID: PMC4894683 DOI: 10.1128/msphere.00051-16] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2016] [Accepted: 03/23/2016] [Indexed: 01/22/2023] Open
Abstract
Chagas disease is caused by insect-transmitted Trypanosoma cruzi. Halting T. cruzi’s life cycle in one of its various human and insect life stages would effectively stop the parasite’s infection cycle. T. cruzi is exposed to a variety of environmental conditions in its different life stages, and gene expression must be remodeled to survive these changes. In this work, we look at the impact that one of these changes, nutrient depletion, has on the expression of the 20 gene products encoded in the mitochondrial genome that is neglected by whole-genome studies. We show increases in mitochondrial RNA abundances in starved insect-stage cells, under two conditions in which transition to the infectious stage occurs or does not. This report is the first to show that T. cruzi mitochondrial gene expression is sensitive to environmental perturbations, consistent with mitochondrial gene expression regulatory pathways being potential antiparasitic targets. Trypanosoma cruzi parasites causing Chagas disease are passed between mammals by the triatomine bug vector. Within the insect, T. cruzi epimastigote-stage cells replicate and progress through the increasingly nutrient-restricted digestive tract, differentiating into infectious, nonreplicative metacyclic trypomastigotes. Thus, we evaluated how nutrient perturbations or metacyclogenesis affects mitochondrial gene expression in different insect life cycle stages. We compared mitochondrial RNA abundances in cultures containing fed, replicating epimastigotes, differentiating cultures containing both starved epimastigotes and metacyclic trypomastigotes and epimastigote starvation cultures. We observed increases in mitochondrial rRNAs and some mRNAs in differentiating cultures. These increases predominated only for the edited CYb mRNA in cultures enriched for metacyclic trypomastigotes. For the other transcripts, abundance increases were linked to starvation and were strongest in culture fractions with a high population of starved epimastigotes. We show that loss of both glucose and amino acids results in rapid increases in RNA abundances that are quickly reduced when these nutrients are returned. Furthermore, the individual RNAs exhibit distinct temporal abundance patterns, suggestive of multiple mechanisms regulating individual transcript abundance. Finally, increases in mitochondrial respiratory complex subunit mRNA abundances were not matched by increases in abundances of nucleus-encoded subunit mRNAs, nor were there statistically significant increases in protein levels of three nucleus-encoded subunits tested. These results show that, similarly to that in T. brucei, the mitochondrial genome in T. cruzi has the potential to alter gene expression in response to environmental or developmental stimuli but for an as-yet-unknown purpose. IMPORTANCE Chagas disease is caused by insect-transmitted Trypanosoma cruzi. Halting T. cruzi’s life cycle in one of its various human and insect life stages would effectively stop the parasite’s infection cycle. T. cruzi is exposed to a variety of environmental conditions in its different life stages, and gene expression must be remodeled to survive these changes. In this work, we look at the impact that one of these changes, nutrient depletion, has on the expression of the 20 gene products encoded in the mitochondrial genome that is neglected by whole-genome studies. We show increases in mitochondrial RNA abundances in starved insect-stage cells, under two conditions in which transition to the infectious stage occurs or does not. This report is the first to show that T. cruzi mitochondrial gene expression is sensitive to environmental perturbations, consistent with mitochondrial gene expression regulatory pathways being potential antiparasitic targets.
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