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Kramer NJ, Prakash G, Isaac RS, Choquet K, Soto I, Petrova B, Merens HE, Kanarek N, Churchman LS. Regulators of mitonuclear balance link mitochondrial metabolism to mtDNA expression. Nat Cell Biol 2023; 25:1575-1589. [PMID: 37770567 DOI: 10.1038/s41556-023-01244-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Accepted: 08/29/2023] [Indexed: 09/30/2023]
Abstract
Mitochondrial oxidative phosphorylation (OXPHOS) complexes are assembled from proteins encoded by both nuclear and mitochondrial DNA. These dual-origin enzymes pose a complex gene regulatory challenge for cells requiring coordinated gene expression across organelles. To identify genes involved in dual-origin protein complex synthesis, we performed fluorescence-activated cell-sorting-based genome-wide screens analysing mutant cells with unbalanced levels of mitochondrial- and nuclear-encoded subunits of Complex IV. We identified genes involved in OXPHOS biogenesis, including two uncharacterized genes: PREPL and NME6. We found that PREPL specifically impacts Complex IV biogenesis by acting at the intersection of mitochondrial lipid metabolism and protein synthesis, whereas NME6, an uncharacterized nucleoside diphosphate kinase, controls OXPHOS biogenesis through multiple mechanisms reliant on its NDPK domain. Firstly, NME6 forms a complex with RCC1L, which together perform nucleoside diphosphate kinase activity to maintain local mitochondrial pyrimidine triphosphate levels essential for mitochondrial RNA abundance. Secondly, NME6 modulates the activity of mitoribosome regulatory complexes, altering mitoribosome assembly and mitochondrial RNA pseudouridylation. Taken together, we propose that NME6 acts as a link between compartmentalized mitochondrial metabolites and mitochondrial gene expression.
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Affiliation(s)
- Nicholas J Kramer
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, MA, USA
| | - Gyan Prakash
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, MA, USA
| | - R Stefan Isaac
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, MA, USA
| | - Karine Choquet
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, MA, USA
| | - Iliana Soto
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, MA, USA
| | - Boryana Petrova
- Department of Pathology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Hope E Merens
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, MA, USA
| | - Naama Kanarek
- Department of Pathology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - L Stirling Churchman
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, MA, USA.
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2
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Martell DJ, Merens HE, Caulier A, Fiorini C, Ulirsch JC, Ietswaart R, Choquet K, Graziadei G, Brancaleoni V, Cappellini MD, Scott C, Roberts N, Proven M, Roy NBA, Babbs C, Higgs DR, Sankaran VG, Churchman LS. RNA polymerase II pausing temporally coordinates cell cycle progression and erythroid differentiation. Dev Cell 2023; 58:2112-2127.e4. [PMID: 37586368 PMCID: PMC10615711 DOI: 10.1016/j.devcel.2023.07.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2023] [Revised: 05/23/2023] [Accepted: 07/25/2023] [Indexed: 08/18/2023]
Abstract
Controlled release of promoter-proximal paused RNA polymerase II (RNA Pol II) is crucial for gene regulation. However, studying RNA Pol II pausing is challenging, as pause-release factors are almost all essential. In this study, we identified heterozygous loss-of-function mutations in SUPT5H, which encodes SPT5, in individuals with β-thalassemia. During erythropoiesis in healthy human cells, cell cycle genes were highly paused as cells transition from progenitors to precursors. When the pathogenic mutations were recapitulated by SUPT5H editing, RNA Pol II pause release was globally disrupted, and as cells began transitioning from progenitors to precursors, differentiation was delayed, accompanied by a transient lag in erythroid-specific gene expression and cell cycle kinetics. Despite this delay, cells terminally differentiate, and cell cycle phase distributions normalize. Therefore, hindering pause release perturbs proliferation and differentiation dynamics at a key transition during erythropoiesis, identifying a role for RNA Pol II pausing in temporally coordinating the cell cycle and erythroid differentiation.
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Affiliation(s)
- Danya J Martell
- Department of Genetics, Harvard University, Boston, MA, USA; Division of Hematology/Oncology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA; Department of Pediatric Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA, USA; Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Hope E Merens
- Department of Genetics, Harvard University, Boston, MA, USA
| | - Alexis Caulier
- Division of Hematology/Oncology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA; Department of Pediatric Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA, USA; Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Claudia Fiorini
- Division of Hematology/Oncology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA; Department of Pediatric Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA, USA; Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | - Jacob C Ulirsch
- Division of Hematology/Oncology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA; Department of Pediatric Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA, USA; Broad Institute of MIT and Harvard, Cambridge, MA, USA
| | | | - Karine Choquet
- Department of Genetics, Harvard University, Boston, MA, USA
| | - Giovanna Graziadei
- Department of Clinical Sciences and Community, University of Milan, IRCCS Ca'Granda Foundation Maggiore Policlinico Hospital, Milan, Italy
| | - Valentina Brancaleoni
- Department of Clinical Sciences and Community, University of Milan, IRCCS Ca'Granda Foundation Maggiore Policlinico Hospital, Milan, Italy
| | - Maria Domenica Cappellini
- Department of Clinical Sciences and Community, University of Milan, IRCCS Ca'Granda Foundation Maggiore Policlinico Hospital, Milan, Italy
| | - Caroline Scott
- MRC Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, UK
| | - Nigel Roberts
- MRC Molecular Haematology Unit, MRC Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, UK
| | - Melanie Proven
- Oxford Genetics Laboratories, Oxford University Hospitals NHS Foundation Trust, Oxford, UK
| | - Noémi B A Roy
- MRC Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, UK; NIHR Oxford Biomedical Research Centre and BRC/NHS Translational Molecular Diagnostics Centre, John Radcliffe Hospital, Oxford, UK; Department of Haematology, Oxford University Hospitals NHS Foundation Trust, Oxford, UK
| | - Christian Babbs
- MRC Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, UK
| | - Douglas R Higgs
- MRC Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, UK
| | - Vijay G Sankaran
- Division of Hematology/Oncology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA; Department of Pediatric Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA, USA; Broad Institute of MIT and Harvard, Cambridge, MA, USA.
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3
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Martell DJ, Merens HE, Fiorini C, Caulier A, Ulirsch JC, Ietswaart R, Choquet K, Graziadei G, Brancaleoni V, Cappellini MD, Scott C, Roberts N, Proven M, Roy NB, Babbs C, Higgs DR, Sankaran VG, Churchman LS. RNA Polymerase II pausing temporally coordinates cell cycle progression and erythroid differentiation. medRxiv 2023:2023.03.03.23286760. [PMID: 36945604 PMCID: PMC10029049 DOI: 10.1101/2023.03.03.23286760] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
The controlled release of promoter-proximal paused RNA polymerase II (Pol II) into productive elongation is a major step in gene regulation. However, functional analysis of Pol II pausing is difficult because factors that regulate pause release are almost all essential. In this study, we identified heterozygous loss-of-function mutations in SUPT5H , which encodes SPT5, in individuals with β-thalassemia unlinked to HBB mutations. During erythropoiesis in healthy human cells, cell cycle genes were highly paused at the transition from progenitors to precursors. When the pathogenic mutations were recapitulated by SUPT5H editing, Pol II pause release was globally disrupted, and the transition from progenitors to precursors was delayed, marked by a transient lag in erythroid-specific gene expression and cell cycle kinetics. Despite this delay, cells terminally differentiate, and cell cycle phase distributions normalize. Therefore, hindering pause release perturbs proliferation and differentiation dynamics at a key transition during erythropoiesis, revealing a role for Pol II pausing in the temporal coordination between the cell cycle and differentiation.
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Affiliation(s)
- Danya J Martell
- Harvard University, Department of Genetics, Boston, MA
- Division of Hematology/Oncology, Boston Children's Hospital, Harvard Medical School, Boston, MA
- Department of Pediatric Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA
- Broad Institute of MIT and Harvard, Cambridge, MA
| | - Hope E Merens
- Harvard University, Department of Genetics, Boston, MA
| | - Claudia Fiorini
- Division of Hematology/Oncology, Boston Children's Hospital, Harvard Medical School, Boston, MA
- Department of Pediatric Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA
- Broad Institute of MIT and Harvard, Cambridge, MA
| | - Alexis Caulier
- Division of Hematology/Oncology, Boston Children's Hospital, Harvard Medical School, Boston, MA
- Department of Pediatric Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA
- Broad Institute of MIT and Harvard, Cambridge, MA
| | - Jacob C Ulirsch
- Division of Hematology/Oncology, Boston Children's Hospital, Harvard Medical School, Boston, MA
- Department of Pediatric Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA
- Broad Institute of MIT and Harvard, Cambridge, MA
| | | | | | - Giovanna Graziadei
- Department of Clinical Sciences and Community, University of Milan, IRCCS Ca'Granda Foundation Maggiore Policlinico Hospital, Milan, Italy
| | - Valentina Brancaleoni
- Department of Clinical Sciences and Community, University of Milan, IRCCS Ca'Granda Foundation Maggiore Policlinico Hospital, Milan, Italy
| | - Maria Domenica Cappellini
- Department of Clinical Sciences and Community, University of Milan, IRCCS Ca'Granda Foundation Maggiore Policlinico Hospital, Milan, Italy
| | - Caroline Scott
- MRC Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, United Kingdom
| | - Nigel Roberts
- MRC Molecular Haematology Unit, MRC Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, UK
| | - Melanie Proven
- Oxford Genetics Laboratories, Oxford University Hospitals NHS Foundation Trust, Oxford, UK
| | - Noémi Ba Roy
- MRC Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, United Kingdom
- NIHR Oxford Biomedical Research Centre and BRC/NHS Translational Molecular Diagnostics Centre, John Radcliffe Hospital, Oxford, UK
- Department of Haematology, Oxford University Hospitals NHS Foundation Trust, Oxford, UK
| | - Christian Babbs
- MRC Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, United Kingdom
| | - Douglas R Higgs
- MRC Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, United Kingdom
| | - Vijay G Sankaran
- Division of Hematology/Oncology, Boston Children's Hospital, Harvard Medical School, Boston, MA
- Department of Pediatric Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, MA
- Broad Institute of MIT and Harvard, Cambridge, MA
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Kramer NJ, Prakash G, Choquet K, Soto I, Petrova B, Merens HE, Kanarek N, Churchman LS. Genome-wide screens for mitonuclear co-regulators uncover links between compartmentalized metabolism and mitochondrial gene expression. bioRxiv 2023:2023.02.11.528118. [PMID: 36798306 PMCID: PMC9934615 DOI: 10.1101/2023.02.11.528118] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/13/2023]
Abstract
Mitochondrial oxidative phosphorylation (OXPHOS) complexes are assembled from proteins encoded by both nuclear and mitochondrial DNA. These dual-origin enzymes pose a complex gene regulatory challenge for cells, in which gene expression must be coordinated across organelles using distinct pools of ribosomes. How cells produce and maintain the accurate subunit stoichiometries for these OXPHOS complexes remains largely unknown. To identify genes involved in dual-origin protein complex synthesis, we performed FACS-based genome-wide screens analyzing mutant cells with unbalanced levels of mitochondrial- and nuclear-encoded subunits of cytochrome c oxidase (Complex IV). We identified novel genes involved in OXPHOS biogenesis, including two uncharacterized genes: PREPL and NME6 . We found that PREPL specifically regulates Complex IV biogenesis by interacting with mitochondrial protein synthesis machinery, while NME6, an uncharacterized nucleoside diphosphate kinase (NDPK), controls OXPHOS complex biogenesis through multiple mechanisms reliant on its NDPK domain. First, NME6 maintains local mitochondrial pyrimidine triphosphate levels essential for mitochondrial RNA abundance. Second, through stabilizing interactions with RCC1L, NME6 modulates the activity of mitoribosome regulatory complexes, leading to disruptions in mitoribosome assembly and mitochondrial RNA pseudouridylation. Taken together, we propose that NME6 acts as a link between compartmentalized mitochondrial metabolites and mitochondrial gene expression. Finally, we present these screens as a resource, providing a catalog of genes involved in mitonuclear gene regulation and OXPHOS biogenesis.
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Drexler HL, Choquet K, Merens HE, Tang PS, Simpson JT, Churchman LS. Revealing nascent RNA processing dynamics with nano-COP. Nat Protoc 2021; 16:1343-1375. [PMID: 33514943 PMCID: PMC8713461 DOI: 10.1038/s41596-020-00469-y] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2020] [Accepted: 11/20/2020] [Indexed: 01/30/2023]
Abstract
During maturation, eukaryotic precursor RNAs undergo processing events including intron splicing, 3'-end cleavage, and polyadenylation. Here we describe nanopore analysis of co-transcriptional processing (nano-COP), a method for probing the timing and patterns of RNA processing. An extension of native elongating transcript sequencing, which quantifies transcription genome-wide through short-read sequencing of nascent RNA 3' ends, nano-COP uses long-read nascent RNA sequencing to observe global patterns of RNA processing. First, nascent RNA is stringently purified through a combination of 4-thiouridine metabolic labeling and cellular fractionation. In contrast to cDNA or short-read-based approaches relying on reverse transcription or amplification, the sample is sequenced directly through nanopores to reveal the native context of nascent RNA. nano-COP identifies both active transcription sites and splice isoforms of single RNA molecules during synthesis, providing insight into patterns of intron removal and the physical coupling between transcription and splicing. The nano-COP protocol yields data within 3 d.
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Affiliation(s)
- Heather L. Drexler
- Department of Genetics, Harvard Medical School, Boston, Massachusetts, USA
| | - Karine Choquet
- Department of Genetics, Harvard Medical School, Boston, Massachusetts, USA
| | - Hope E. Merens
- Department of Genetics, Harvard Medical School, Boston, Massachusetts, USA
| | - Paul S. Tang
- Ontario Institute for Cancer Research, Toronto, Ontario, Canada
| | - Jared T. Simpson
- Ontario Institute for Cancer Research and Department of Computer Science, University of Toronto, Toronto, Ontario, Canada
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