1
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Boddu PC, Gupta AK, Roy R, De La Peña Avalos B, Olazabal-Herrero A, Neuenkirchen N, Zimmer JT, Chandhok NS, King D, Nannya Y, Ogawa S, Lin H, Simon MD, Dray E, Kupfer GM, Verma A, Neugebauer KM, Pillai MM. Transcription elongation defects link oncogenic SF3B1 mutations to targetable alterations in chromatin landscape. Mol Cell 2024; 84:1475-1495.e18. [PMID: 38521065 PMCID: PMC11061666 DOI: 10.1016/j.molcel.2024.02.032] [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: 03/28/2023] [Revised: 11/26/2023] [Accepted: 02/27/2024] [Indexed: 03/25/2024]
Abstract
Transcription and splicing of pre-messenger RNA are closely coordinated, but how this functional coupling is disrupted in human diseases remains unexplored. Using isogenic cell lines, patient samples, and a mutant mouse model, we investigated how cancer-associated mutations in SF3B1 alter transcription. We found that these mutations reduce the elongation rate of RNA polymerase II (RNAPII) along gene bodies and its density at promoters. The elongation defect results from disrupted pre-spliceosome assembly due to impaired protein-protein interactions of mutant SF3B1. The decreased promoter-proximal RNAPII density reduces both chromatin accessibility and H3K4me3 marks at promoters. Through an unbiased screen, we identified epigenetic factors in the Sin3/HDAC/H3K4me pathway, which, when modulated, reverse both transcription and chromatin changes. Our findings reveal how splicing factor mutant states behave functionally as epigenetic disorders through impaired transcription-related changes to the chromatin landscape. We also present a rationale for targeting the Sin3/HDAC complex as a therapeutic strategy.
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Affiliation(s)
- Prajwal C Boddu
- Section of Hematology, Yale Cancer Center and Department of Internal Medicine, Yale University School of Medicine, 300 George Street, Suite 786, New Haven, CT 06511, USA
| | - Abhishek K Gupta
- Section of Hematology, Yale Cancer Center and Department of Internal Medicine, Yale University School of Medicine, 300 George Street, Suite 786, New Haven, CT 06511, USA
| | - Rahul Roy
- Section of Hematology, Yale Cancer Center and Department of Internal Medicine, Yale University School of Medicine, 300 George Street, Suite 786, New Haven, CT 06511, USA
| | - Bárbara De La Peña Avalos
- Department of Biochemistry and Structural Biology, University of Texas Health Science Center (UTHSC) at San Antonio, San Antonio, TX, USA
| | - Anne Olazabal-Herrero
- Section of Hematology, Yale Cancer Center and Department of Internal Medicine, Yale University School of Medicine, 300 George Street, Suite 786, New Haven, CT 06511, USA
| | - Nils Neuenkirchen
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT, USA; Yale Stem Cell Center, Yale University School of Medicine, New Haven, CT, USA
| | - Joshua T Zimmer
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA
| | - Namrata S Chandhok
- Division of Hematology, Department of Medicine, Sylvester Comprehensive Cancer Center, University of Miami, Miami, FL, USA
| | - Darren King
- Section of Hematology and Medical Oncology, Department of Internal Medicine and Rogel Cancer Center, University of Michigan Health, Ann Arbor, MI, USA
| | - Yasuhito Nannya
- Department of Pathology and Tumor Biology, Kyoto University, Kyoto, Japan
| | - Seishi Ogawa
- Department of Pathology and Tumor Biology, Kyoto University, Kyoto, Japan
| | - Haifan Lin
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT, USA; Yale Stem Cell Center, Yale University School of Medicine, New Haven, CT, USA
| | - Matthew D Simon
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA
| | - Eloise Dray
- Department of Biochemistry and Structural Biology, University of Texas Health Science Center (UTHSC) at San Antonio, San Antonio, TX, USA
| | - Gary M Kupfer
- Department of Oncology and Pediatrics, Lombardi Comprehensive Cancer Center, Georgetown University, Washington, DC, USA
| | - Amit Verma
- Division of Hemato-Oncology, Department of Medicine and Department of Developmental and Molecular Biology, Albert Einstein-Montefiore Cancer Center, New York, USA
| | - Karla M Neugebauer
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA; Yale Center for RNA Science and Medicine, Yale University, New Haven, CT, USA
| | - Manoj M Pillai
- Section of Hematology, Yale Cancer Center and Department of Internal Medicine, Yale University School of Medicine, 300 George Street, Suite 786, New Haven, CT 06511, USA; Yale Stem Cell Center, Yale University School of Medicine, New Haven, CT, USA; Yale Center for RNA Science and Medicine, Yale University, New Haven, CT, USA; Department of Pathology, Yale University School of Medicine, New Haven, CT, USA.
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2
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Shine M, Gordon J, Schärfen L, Zigackova D, Herzel L, Neugebauer KM. Co-transcriptional gene regulation in eukaryotes and prokaryotes. Nat Rev Mol Cell Biol 2024:10.1038/s41580-024-00706-2. [PMID: 38509203 DOI: 10.1038/s41580-024-00706-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/19/2024] [Indexed: 03/22/2024]
Abstract
Many steps of RNA processing occur during transcription by RNA polymerases. Co-transcriptional activities are deemed commonplace in prokaryotes, in which the lack of membrane barriers allows mixing of all gene expression steps, from transcription to translation. In the past decade, an extraordinary level of coordination between transcription and RNA processing has emerged in eukaryotes. In this Review, we discuss recent developments in our understanding of co-transcriptional gene regulation in both eukaryotes and prokaryotes, comparing methodologies and mechanisms, and highlight striking parallels in how RNA polymerases interact with the machineries that act on nascent RNA. The development of RNA sequencing and imaging techniques that detect transient transcription and RNA processing intermediates has facilitated discoveries of transcription coordination with splicing, 3'-end cleavage and dynamic RNA folding and revealed physical contacts between processing machineries and RNA polymerases. Such studies indicate that intron retention in a given nascent transcript can prevent 3'-end cleavage and cause transcriptional readthrough, which is a hallmark of eukaryotic cellular stress responses. We also discuss how coordination between nascent RNA biogenesis and transcription drives fundamental aspects of gene expression in both prokaryotes and eukaryotes.
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Affiliation(s)
- Morgan Shine
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA
| | - Jackson Gordon
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA
| | - Leonard Schärfen
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA
| | - Dagmar Zigackova
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA
| | - Lydia Herzel
- Department of Biology, Chemistry, and Pharmacy, Freie Universität Berlin, Berlin, Germany.
| | - Karla M Neugebauer
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA.
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3
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Neugebauer KM. How cell biology can save the planet. Nat Cell Biol 2024; 26:4. [PMID: 38228830 DOI: 10.1038/s41556-023-01305-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2024]
Affiliation(s)
- Karla M Neugebauer
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA.
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4
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Podszywalow-Bartnicka P, Neugebauer KM. Splicing under stress: A matter of time and place. J Cell Biol 2023; 222:e202311014. [PMID: 37988026 PMCID: PMC10660129 DOI: 10.1083/jcb.202311014] [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] [Indexed: 11/22/2023] Open
Abstract
Excision of introns during splicing regulates gene expression. In this issue, work by Sung et al. (https://doi.org/10.1083/jcb.202111151) demonstrates that the timing of intron removal in response to stress is coordinated in nuclear speckles, adding a component of spatial regulation to co-/post-transcriptional splicing.
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Affiliation(s)
| | - Karla M. Neugebauer
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven CT, USA
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5
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Barentine AES, Lin Y, Courvan EM, Kidd P, Liu M, Balduf L, Phan T, Rivera-Molina F, Grace MR, Marin Z, Lessard M, Rios Chen J, Wang S, Neugebauer KM, Bewersdorf J, Baddeley D. An integrated platform for high-throughput nanoscopy. Nat Biotechnol 2023; 41:1549-1556. [PMID: 36914886 PMCID: PMC10497732 DOI: 10.1038/s41587-023-01702-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [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: 06/02/2022] [Accepted: 02/02/2023] [Indexed: 03/16/2023]
Abstract
Single-molecule localization microscopy enables three-dimensional fluorescence imaging at tens-of-nanometer resolution, but requires many camera frames to reconstruct a super-resolved image. This limits the typical throughput to tens of cells per day. While frame rates can now be increased by over an order of magnitude, the large data volumes become limiting in existing workflows. Here we present an integrated acquisition and analysis platform leveraging microscopy-specific data compression, distributed storage and distributed analysis to enable an acquisition and analysis throughput of 10,000 cells per day. The platform facilitates graphically reconfigurable analyses to be automatically initiated from the microscope during acquisition and remotely executed, and can even feed back and queue new acquisition tasks on the microscope. We demonstrate the utility of this framework by imaging hundreds of cells per well in multi-well sample formats. Our platform, implemented within the PYthon-Microscopy Environment (PYME), is easily configurable to control custom microscopes, and includes a plugin framework for user-defined extensions.
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Affiliation(s)
- Andrew E S Barentine
- Department of Cell Biology, Yale School of Medicine, New Haven, CT, USA
- Department of Biomedical Engineering, Yale University, New Haven, CT, USA
| | - Yu Lin
- Department of Cell Biology, Yale School of Medicine, New Haven, CT, USA
- Department of Biomedical Engineering, Yale University, New Haven, CT, USA
| | - Edward M Courvan
- Department of Cell Biology, Yale School of Medicine, New Haven, CT, USA
- Department of Molecular Biophysics and Biochemistry, Yale School of Medicine, New Haven, CT, USA
| | - Phylicia Kidd
- Department of Cell Biology, Yale School of Medicine, New Haven, CT, USA
| | - Miao Liu
- Department of Genetics, Yale School of Medicine, New Haven, CT, USA
| | - Leonhard Balduf
- Department of Cell Biology, Yale School of Medicine, New Haven, CT, USA
- Department of Computer Science and Mathematics, University of Applied Sciences, Munich, Germany
| | - Timy Phan
- Department of Cell Biology, Yale School of Medicine, New Haven, CT, USA
- Department of Computer Science and Mathematics, University of Applied Sciences, Munich, Germany
| | | | - Michael R Grace
- Department of Cell Biology, Yale School of Medicine, New Haven, CT, USA
| | - Zach Marin
- Department of Cell Biology, Yale School of Medicine, New Haven, CT, USA
- Department of Biomedical Engineering, Yale University, New Haven, CT, USA
- Auckland Bioengineering Institute at University of Auckland, Auckland, New Zealand
| | - Mark Lessard
- Department of Cell Biology, Yale School of Medicine, New Haven, CT, USA
| | - Juliana Rios Chen
- Department of Cell Biology, Yale School of Medicine, New Haven, CT, USA
| | - Siyuan Wang
- Department of Cell Biology, Yale School of Medicine, New Haven, CT, USA
- Department of Genetics, Yale School of Medicine, New Haven, CT, USA
| | - Karla M Neugebauer
- Department of Cell Biology, Yale School of Medicine, New Haven, CT, USA
- Department of Molecular Biophysics and Biochemistry, Yale School of Medicine, New Haven, CT, USA
| | - Joerg Bewersdorf
- Department of Cell Biology, Yale School of Medicine, New Haven, CT, USA.
- Department of Biomedical Engineering, Yale University, New Haven, CT, USA.
- Department of Physics, Yale University, New Haven, CT, USA.
- Nanobiology Institute, Yale University, West Haven, CT, USA.
| | - David Baddeley
- Department of Cell Biology, Yale School of Medicine, New Haven, CT, USA.
- Auckland Bioengineering Institute at University of Auckland, Auckland, New Zealand.
- Nanobiology Institute, Yale University, West Haven, CT, USA.
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6
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Šimčíková D, Gelles-Watnick S, Neugebauer KM. Tudor-dimethylarginine interactions: the condensed version. Trends Biochem Sci 2023; 48:689-698. [PMID: 37156649 PMCID: PMC10524826 DOI: 10.1016/j.tibs.2023.04.003] [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: 10/11/2022] [Revised: 04/09/2023] [Accepted: 04/10/2023] [Indexed: 05/10/2023]
Abstract
Biomolecular condensates (BMCs) can facilitate or inhibit diverse cellular functions. BMC formation is driven by noncovalent protein-protein, protein-RNA, and RNA-RNA interactions. Here, we focus on Tudor domain-containing proteins - such as survival motor neuron protein (SMN) - that contribute to BMC formation by binding to dimethylarginine (DMA) modifications on protein ligands. SMN is present in RNA-rich BMCs, and its absence causes spinal muscular atrophy (SMA). SMN's Tudor domain forms cytoplasmic and nuclear BMCs, but its DMA ligands are largely unknown, highlighting open questions about the function of SMN. Moreover, DMA modification can alter intramolecular interactions and affect protein localization. Despite these emerging functions, the lack of direct methods of DMA detection remains an obstacle to understanding Tudor-DMA interactions in cells.
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Affiliation(s)
- Daniela Šimčíková
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520, USA
| | - Sara Gelles-Watnick
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520, USA
| | - Karla M Neugebauer
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520, USA.
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7
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Bergfort A, Neugebauer KM. The promoter as a trip navigator: Guiding alternative polyadenylation site destinations. Mol Cell 2023; 83:2395-2397. [PMID: 37478824 DOI: 10.1016/j.molcel.2023.06.022] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [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: 06/20/2023] [Revised: 06/20/2023] [Accepted: 06/20/2023] [Indexed: 07/23/2023]
Abstract
Alfonso-Gonzalez et al.1 present an innovative combination of long-read-sequencing approaches that reveal coupling of alternative transcription start sites and alternative polyadenylation site usage on a global level.
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Affiliation(s)
- Alexandra Bergfort
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA
| | - Karla M Neugebauer
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA.
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8
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Boddu PC, Gupta A, Roy R, De La Pena Avalos B, Herrero AO, Neuenkirchen N, Zimmer J, Chandhok N, King D, Nannya Y, Ogawa S, Lin H, Simon M, Dray E, Kupfer G, Verma AK, Neugebauer KM, Pillai MM. Transcription elongation defects link oncogenic splicing factor mutations to targetable alterations in chromatin landscape. bioRxiv 2023:2023.02.25.530019. [PMID: 36891287 PMCID: PMC9994134 DOI: 10.1101/2023.02.25.530019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/01/2023]
Abstract
Transcription and splicing of pre-messenger RNA are closely coordinated, but how this functional coupling is disrupted in human disease remains unexplored. Here, we investigated the impact of non-synonymous mutations in SF3B1 and U2AF1, two commonly mutated splicing factors in cancer, on transcription. We find that the mutations impair RNA Polymerase II (RNAPII) transcription elongation along gene bodies leading to transcription-replication conflicts, replication stress and altered chromatin organization. This elongation defect is linked to disrupted pre-spliceosome assembly due to impaired association of HTATSF1 with mutant SF3B1. Through an unbiased screen, we identified epigenetic factors in the Sin3/HDAC complex, which, when modulated, normalize transcription defects and their downstream effects. Our findings shed light on the mechanisms by which oncogenic mutant spliceosomes impact chromatin organization through their effects on RNAPII transcription elongation and present a rationale for targeting the Sin3/HDAC complex as a potential therapeutic strategy. GRAPHICAL ABSTRACT HIGHLIGHTS Oncogenic mutations of SF3B1 and U2AF1 cause a gene-body RNAPII elongation defectRNAPII transcription elongation defect leads to transcription replication conflicts, DNA damage response, and changes to chromatin organization and H3K4me3 marksThe transcription elongation defect is linked to disruption of the early spliceosome formation through impaired interaction of HTATSF1 with mutant SF3B1.Changes to chromatin organization reveal potential therapeutic strategies by targeting the Sin3/HDAC pathway.
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9
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Courchaine E, Gelles-Watnick S, Machyna M, Straube K, Sauyet S, Enright J, Neugebauer KM. The coilin N-terminus mediates multivalent interactions between coilin and Nopp140 to form and maintain Cajal bodies. Nat Commun 2022; 13:6005. [PMID: 36224177 PMCID: PMC9556525 DOI: 10.1038/s41467-022-33434-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2021] [Accepted: 09/16/2022] [Indexed: 11/25/2022] Open
Abstract
Cajal bodies (CBs) are ubiquitous nuclear membraneless organelles (MLOs) that concentrate and promote efficient biogenesis of snRNA-protein complexes involved in splicing (snRNPs). Depletion of the CB scaffolding protein coilin disperses snRNPs, making CBs a model system for studying the structure and function of MLOs. Although it is assumed that CBs form through condensation, the biomolecular interactions responsible remain elusive. Here, we discover the unexpected capacity of coilin’s N-terminal domain (NTD) to form extensive fibrils in the cytoplasm and discrete nuclear puncta in vivo. Single amino acid mutational analysis reveals distinct molecular interactions between coilin NTD proteins to form fibrils and additional NTD interactions with the nuclear Nopp140 protein to form puncta. We provide evidence that Nopp140 has condensation capacity and is required for CB assembly. From these observations, we propose a model in which coilin NTD–NTD mediated assemblies make multivalent contacts with Nopp140 to achieve biomolecular condensation in the nucleus. Cajal bodies are membraneless organelles scaffolded by coilin protein. Here, coilin–coilin and coilin–Nopp140 interaction sites are identified and perturbed, revealing coilin’s capacity to form long fibrils and be remodeled into spherical structures.
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Affiliation(s)
- Edward Courchaine
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA
| | - Sara Gelles-Watnick
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA
| | - Martin Machyna
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA
| | - Korinna Straube
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA
| | - Sarah Sauyet
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA
| | - Jade Enright
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA
| | - Karla M Neugebauer
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA.
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10
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Karmakar S, Ramirez O, Paul KV, Gupta AK, Kumari V, Botti V, de Los Mozos IR, Neuenkirchen N, Ross RJ, Karanicolas J, Neugebauer KM, Pillai MM. Integrative genome-wide analysis reveals EIF3A as a key downstream regulator of translational repressor protein Musashi 2 (MSI2). NAR Cancer 2022; 4:zcac015. [PMID: 35528200 PMCID: PMC9070473 DOI: 10.1093/narcan/zcac015] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Revised: 04/04/2022] [Accepted: 04/19/2022] [Indexed: 01/29/2023] Open
Abstract
Musashi 2 (MSI2) is an RNA binding protein (RBP) that regulates asymmetric cell division and cell fate decisions in normal and cancer stem cells. MSI2 appears to repress translation by binding to 3′ untranslated regions (3′UTRs) of mRNA, but the identity of functional targets remains unknown. Here, we used individual nucleotide resolution cross-linking and immunoprecipitation (iCLIP) to identify direct RNA binding partners of MSI2 and integrated these data with polysome profiling to obtain insights into MSI2 function. iCLIP revealed specific MSI2 binding to thousands of mRNAs largely in 3′UTRs, but translational differences were restricted to a small fraction of these transcripts, indicating that MSI2 regulation is not triggered by simple binding. Instead, the functional targets identified here were bound at higher density and contain more ‘UAG’ motifs compared to targets bound nonproductively. To further distinguish direct and indirect targets, MSI2 was acutely depleted. Surprisingly, only 50 transcripts were found to undergo translational induction on acute loss. Using complementary approaches, we determined eukaryotic translation initiation factor 3A (EIF3A) to be an immediate, direct target. We propose that MSI2 downregulation of EIF3A amplifies these effects on translation. Our results also underscore the challenges in defining functional targets of RBPs since mere binding does not imply a discernible functional interaction.
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Affiliation(s)
| | - Oscar Ramirez
- Section of Hematology, Yale Cancer Center, New Haven, CT 06511, USA
| | - Kiran V Paul
- Section of Hematology, Yale Cancer Center, New Haven, CT 06511, USA
| | - Abhishek K Gupta
- Section of Hematology, Yale Cancer Center, New Haven, CT 06511, USA
| | - Vandana Kumari
- Section of Hematology, Yale Cancer Center, New Haven, CT 06511, USA
| | - Valentina Botti
- Department of Molecular Biophysics and Biochemistry, Yale University School of Medicine, New Haven, CT 06510, USA
| | - Igor Ruiz de Los Mozos
- Institute of Neurology, University College London and The Francis Crick Institute, London NW1 1AT, UK
| | - Nils Neuenkirchen
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT 06511, USA
| | - Robert J Ross
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT 06511, USA
| | - John Karanicolas
- Program in Molecular Therapeutics, Fox Chase Cancer Center, Philadelphia, PA 19111, USA
| | - Karla M Neugebauer
- Department of Molecular Biophysics and Biochemistry, Yale University School of Medicine, New Haven, CT 06510, USA
| | - Manoj M Pillai
- Section of Hematology, Yale Cancer Center, New Haven, CT 06511, USA
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11
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Draycott AS, Schaening-Burgos C, Rojas-Duran MF, Wilson L, Schärfen L, Neugebauer KM, Nachtergaele S, Gilbert WV. Transcriptome-wide mapping reveals a diverse dihydrouridine landscape including mRNA. PLoS Biol 2022; 20:e3001622. [PMID: 35609439 PMCID: PMC9129914 DOI: 10.1371/journal.pbio.3001622] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2021] [Accepted: 04/07/2022] [Indexed: 11/19/2022] Open
Abstract
Dihydrouridine is a modified nucleotide universally present in tRNAs, but the complete dihydrouridine landscape is unknown in any organism. We introduce dihydrouridine sequencing (D-seq) for transcriptome-wide mapping of D with single-nucleotide resolution and use it to uncover novel classes of dihydrouridine-containing RNA in yeast which include mRNA and small nucleolar RNA (snoRNA). The novel D sites are concentrated in conserved stem-loop regions consistent with a role for D in folding many functional RNA structures. We demonstrate dihydrouridine synthase (DUS)-dependent changes in splicing of a D-containing pre-mRNA in cells and show that D-modified mRNAs can be efficiently translated by eukaryotic ribosomes in vitro. This work establishes D as a new functional component of the mRNA epitranscriptome and paves the way for identifying the RNA targets of multiple DUS enzymes that are dysregulated in human disease.
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Affiliation(s)
- Austin S. Draycott
- Yale School of Medicine, Department of Molecular Biophysics & Biochemistry, New Haven, Connecticut, United States of America
| | - Cassandra Schaening-Burgos
- Massachusetts Institute of Technology, Department of Biology, Cambridge, Massachusetts, United States of America
| | - Maria F. Rojas-Duran
- Yale School of Medicine, Department of Molecular Biophysics & Biochemistry, New Haven, Connecticut, United States of America
| | - Loren Wilson
- Yale University, Department of Molecular, Cellular, and Developmental Biology, New Haven, Connecticut, United States of America
| | - Leonard Schärfen
- Yale School of Medicine, Department of Molecular Biophysics & Biochemistry, New Haven, Connecticut, United States of America
| | - Karla M. Neugebauer
- Yale School of Medicine, Department of Molecular Biophysics & Biochemistry, New Haven, Connecticut, United States of America
| | - Sigrid Nachtergaele
- Yale University, Department of Molecular, Cellular, and Developmental Biology, New Haven, Connecticut, United States of America
| | - Wendy V. Gilbert
- Yale School of Medicine, Department of Molecular Biophysics & Biochemistry, New Haven, Connecticut, United States of America
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12
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Biancon G, Joshi P, Zimmer JT, Hunck T, Gao Y, Lessard MD, Courchaine E, Barentine AES, Machyna M, Botti V, Qin A, Gbyli R, Patel A, Song Y, Kiefer L, Viero G, Neuenkirchen N, Lin H, Bewersdorf J, Simon MD, Neugebauer KM, Tebaldi T, Halene S. Precision analysis of mutant U2AF1 activity reveals deployment of stress granules in myeloid malignancies. Mol Cell 2022; 82:1107-1122.e7. [PMID: 35303483 PMCID: PMC8988922 DOI: 10.1016/j.molcel.2022.02.025] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Revised: 12/21/2021] [Accepted: 02/15/2022] [Indexed: 12/13/2022]
Abstract
Splicing factor mutations are common among cancers, recently emerging as drivers of myeloid malignancies. U2AF1 carries hotspot mutations in its RNA-binding motifs; however, how they affect splicing and promote cancer remain unclear. The U2AF1/U2AF2 heterodimer is critical for 3' splice site (3'SS) definition. To specifically unmask changes in U2AF1 function in vivo, we developed a crosslinking and immunoprecipitation procedure that detects contacts between U2AF1 and the 3'SS AG at single-nucleotide resolution. Our data reveal that the U2AF1 S34F and Q157R mutants establish new 3'SS contacts at -3 and +1 nucleotides, respectively. These effects compromise U2AF2-RNA interactions, resulting predominantly in intron retention and exon exclusion. Integrating RNA binding, splicing, and turnover data, we predicted that U2AF1 mutations directly affect stress granule components, which was corroborated by single-cell RNA-seq. Remarkably, U2AF1-mutant cell lines and patient-derived MDS/AML blasts displayed a heightened stress granule response, pointing to a novel role for biomolecular condensates in adaptive oncogenic strategies.
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Affiliation(s)
- Giulia Biancon
- Section of Hematology, Department of Internal Medicine, Yale Comprehensive Cancer Center, Yale University School of Medicine, New Haven, CT, USA.
| | - Poorval Joshi
- Section of Hematology, Department of Internal Medicine, Yale Comprehensive Cancer Center, Yale University School of Medicine, New Haven, CT, USA
| | - Joshua T Zimmer
- Department of Molecular Biophysics and Biochemistry, Yale University School of Medicine, New Haven, CT, USA; Institute for Biomolecular Design and Discovery, Yale University, West Haven, CT, USA
| | - Torben Hunck
- Section of Hematology, Department of Internal Medicine, Yale Comprehensive Cancer Center, Yale University School of Medicine, New Haven, CT, USA
| | - Yimeng Gao
- Section of Hematology, Department of Internal Medicine, Yale Comprehensive Cancer Center, Yale University School of Medicine, New Haven, CT, USA
| | - Mark D Lessard
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT, USA
| | - Edward Courchaine
- Department of Molecular Biophysics and Biochemistry, Yale University School of Medicine, New Haven, CT, USA
| | - Andrew E S Barentine
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT, USA; Department of Biomedical Engineering, Yale University, New Haven, CT, USA
| | - Martin Machyna
- Department of Molecular Biophysics and Biochemistry, Yale University School of Medicine, New Haven, CT, USA
| | - Valentina Botti
- Department of Molecular Biophysics and Biochemistry, Yale University School of Medicine, New Haven, CT, USA
| | - Ashley Qin
- Section of Hematology, Department of Internal Medicine, Yale Comprehensive Cancer Center, Yale University School of Medicine, New Haven, CT, USA
| | - Rana Gbyli
- Section of Hematology, Department of Internal Medicine, Yale Comprehensive Cancer Center, Yale University School of Medicine, New Haven, CT, USA
| | - Amisha Patel
- Section of Hematology, Department of Internal Medicine, Yale Comprehensive Cancer Center, Yale University School of Medicine, New Haven, CT, USA
| | - Yuanbin Song
- Section of Hematology, Department of Internal Medicine, Yale Comprehensive Cancer Center, Yale University School of Medicine, New Haven, CT, USA; Department of Hematologic Oncology, Sun Yat-Sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangzhou, China
| | - Lea Kiefer
- Department of Molecular Biophysics and Biochemistry, Yale University School of Medicine, New Haven, CT, USA; Department of Neurology, University of California, San Francisco, San Francisco, CA, USA
| | | | - Nils Neuenkirchen
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT, USA; Yale Stem Cell Center, Yale University School of Medicine, New Haven, CT, USA
| | - Haifan Lin
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT, USA; Yale Stem Cell Center, Yale University School of Medicine, New Haven, CT, USA; Yale Center for RNA Science and Medicine, Yale University School of Medicine, New Haven, CT, USA
| | - Joerg Bewersdorf
- Department of Cell Biology, Yale University School of Medicine, New Haven, CT, USA; Department of Biomedical Engineering, Yale University, New Haven, CT, USA
| | - Matthew D Simon
- Department of Molecular Biophysics and Biochemistry, Yale University School of Medicine, New Haven, CT, USA; Yale Center for RNA Science and Medicine, Yale University School of Medicine, New Haven, CT, USA; Institute for Biomolecular Design and Discovery, Yale University, West Haven, CT, USA
| | - Karla M Neugebauer
- Department of Molecular Biophysics and Biochemistry, Yale University School of Medicine, New Haven, CT, USA; Yale Center for RNA Science and Medicine, Yale University School of Medicine, New Haven, CT, USA
| | - Toma Tebaldi
- Section of Hematology, Department of Internal Medicine, Yale Comprehensive Cancer Center, Yale University School of Medicine, New Haven, CT, USA; Department of Cellular, Computational and Integrative Biology (CIBIO), University of Trento, Trento, Italy.
| | - Stephanie Halene
- Section of Hematology, Department of Internal Medicine, Yale Comprehensive Cancer Center, Yale University School of Medicine, New Haven, CT, USA; Yale Stem Cell Center, Yale University School of Medicine, New Haven, CT, USA; Yale Center for RNA Science and Medicine, Yale University School of Medicine, New Haven, CT, USA; Department of Pathology, Yale University School of Medicine, New Haven, CT, USA.
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13
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Barentine AE, Lin Y, Courvan EM, Kidd P, Liu M, Balduf L, Phan T, Rivera-Molina F, Grace MR, Marin Z, Rios Chen J, Wang S, Neugebauer KM, Baddeley D, Bewersdorf J. PYME: an integrated platform for high-throughput nanoscopy. Biophys J 2022. [DOI: 10.1016/j.bpj.2021.11.2009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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14
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Schärfen L, Zigackova D, Reimer KA, Stark MR, Slat VA, Francoeur NJ, Wells ML, Zhou L, Blackshear PJ, Neugebauer KM, Rader SD. Identification of Alternative Polyadenylation in Cyanidioschyzon merolae Through Long-Read Sequencing of mRNA. Front Genet 2022; 12:818697. [PMID: 35154260 PMCID: PMC8831791 DOI: 10.3389/fgene.2021.818697] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2021] [Accepted: 12/22/2021] [Indexed: 12/04/2022] Open
Abstract
Alternative polyadenylation (APA) is widespread among metazoans and has been shown to have important impacts on mRNA stability and protein expression. Beyond a handful of well-studied organisms, however, its existence and consequences have not been well investigated. We therefore turned to the deep-branching red alga, Cyanidioschyzon merolae, to study the biology of polyadenylation in an organism highly diverged from humans and yeast. C. merolae is an acidothermophilic alga that lives in volcanic hot springs. It has a highly reduced genome (16.5 Mbp) and has lost all but 27 of its introns and much of its splicing machinery, suggesting that it has been under substantial pressure to simplify its RNA processing pathways. We used long-read sequencing to assess the key features of C. merolae mRNAs, including splicing status and polyadenylation cleavage site (PAS) usage. Splicing appears to be less efficient in C. merolae compared with yeast, flies, and mammalian cells. A high proportion of transcripts (63%) have at least two distinct PAS’s, and 34% appear to utilize three or more sites. The apparent polyadenylation signal UAAA is used in more than 90% of cases, in cells grown in both rich media or limiting nitrogen. Our documentation of APA for the first time in this non-model organism highlights its conservation and likely biological importance of this regulatory step in gene expression.
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Affiliation(s)
- Leonard Schärfen
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, United States
| | - Dagmar Zigackova
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, United States
| | - Kirsten A. Reimer
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, United States
| | - Martha R. Stark
- Department of Chemistry, University of Northern British Columbia, Prince George, BC, Canada
| | - Viktor A. Slat
- Department of Chemistry, University of Northern British Columbia, Prince George, BC, Canada
| | - Nancy J. Francoeur
- Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, United States
| | - Melissa L. Wells
- The Signal Transduction Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, Durham, NC, United States
| | - Lecong Zhou
- Integrative Bioinformatics Support Group, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, Durham, NC, United States
| | - Perry J. Blackshear
- The Signal Transduction Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, Durham, NC, United States
| | - Karla M. Neugebauer
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, United States
- *Correspondence: Stephen D. Rader, ; Karla M. Neugebauer,
| | - Stephen D. Rader
- Department of Chemistry, University of Northern British Columbia, Prince George, BC, Canada
- *Correspondence: Stephen D. Rader, ; Karla M. Neugebauer,
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15
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Boddu PC, Gupta AK, Kim JS, Neugebauer KM, Waldman T, Pillai MM. Generation of scalable cancer models by combining AAV-intron-trap, CRISPR/Cas9, and inducible Cre-recombinase. Commun Biol 2021; 4:1184. [PMID: 34645977 PMCID: PMC8514589 DOI: 10.1038/s42003-021-02690-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2021] [Accepted: 09/15/2021] [Indexed: 11/09/2022] Open
Abstract
Scalable isogenic models of cancer-associated mutations are critical to studying dysregulated gene function. Nonsynonymous mutations of splicing factors, which typically affect one allele, are common in many cancers, but paradoxically confer growth disadvantage to cell lines, making their generation and expansion challenging. Here, we combine AAV-intron trap, CRISPR/Cas9, and inducible Cre-recombinase systems to achieve >90% efficiency to introduce the oncogenic K700E mutation in SF3B1, a splicing factor commonly mutated in multiple cancers. The intron-trap design of AAV vector limits editing to one allele. CRISPR/Cas9-induced double stranded DNA breaks direct homologous recombination to the desired genomic locus. Inducible Cre-recombinase allows for the expansion of cells prior to loxp excision and expression of the mutant allele. Importantly, AAV or CRISPR/Cas9 alone results in much lower editing efficiency and the edited cells do not expand due to toxicity of SF3B1-K700E. Our approach can be readily adapted to generate scalable isogenic systems where mutant oncogenes confer a growth disadvantage.
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Affiliation(s)
- Prajwal C. Boddu
- grid.47100.320000000419368710Section of Hematology, Yale Cancer Center, Yale University School of Medicine, New Haven, CT USA
| | - Abhishek K. Gupta
- grid.47100.320000000419368710Section of Hematology, Yale Cancer Center, Yale University School of Medicine, New Haven, CT USA
| | - Jung-Sik Kim
- grid.213910.80000 0001 1955 1644Department of Oncology, Molecular Biology and Genetics, Lombardi Cancer Center, Georgetown University, Washington, DC USA
| | - Karla M. Neugebauer
- grid.47100.320000000419368710Department of Molecular Biophysics and Biochemistry, Yale University School of Medicine, New Haven, CT USA
| | - Todd Waldman
- grid.213910.80000 0001 1955 1644Department of Oncology, Molecular Biology and Genetics, Lombardi Cancer Center, Georgetown University, Washington, DC USA
| | - Manoj M. Pillai
- grid.47100.320000000419368710Section of Hematology, Yale Cancer Center, Yale University School of Medicine, New Haven, CT USA ,grid.47100.320000000419368710Department of Pathology, Yale University School of Medicine, New Haven, CT USA
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16
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Courchaine EM, Barentine AES, Straube K, Lee DR, Bewersdorf J, Neugebauer KM. DMA-tudor interaction modules control the specificity of in vivo condensates. Cell 2021; 184:3612-3625.e17. [PMID: 34115980 DOI: 10.1016/j.cell.2021.05.008] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Revised: 12/21/2020] [Accepted: 05/07/2021] [Indexed: 12/31/2022]
Abstract
Biomolecular condensation is a widespread mechanism of cellular compartmentalization. Because the "survival of motor neuron protein" (SMN) is implicated in the formation of three different membraneless organelles (MLOs), we hypothesized that SMN promotes condensation. Unexpectedly, we found that SMN's globular tudor domain was sufficient for dimerization-induced condensation in vivo, whereas its two intrinsically disordered regions (IDRs) were not. Binding to dimethylarginine (DMA) modified protein ligands was required for condensate formation by the tudor domains in SMN and at least seven other fly and human proteins. Remarkably, asymmetric versus symmetric DMA determined whether two distinct nuclear MLOs-gems and Cajal bodies-were separate or "docked" to one another. This substructure depended on the presence of either asymmetric or symmetric DMA as visualized with sub-diffraction microscopy. Thus, DMA-tudor interaction modules-combinations of tudor domains bound to their DMA ligand(s)-represent versatile yet specific regulators of MLO assembly, composition, and morphology.
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Affiliation(s)
- Edward M Courchaine
- Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520, USA
| | - Andrew E S Barentine
- Cell Biology, Yale University, New Haven, CT 06520, USA; Biomedical Engineering, Yale University, New Haven, CT 06520, USA
| | - Korinna Straube
- Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520, USA
| | | | - Joerg Bewersdorf
- Cell Biology, Yale University, New Haven, CT 06520, USA; Biomedical Engineering, Yale University, New Haven, CT 06520, USA
| | - Karla M Neugebauer
- Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520, USA; Cell Biology, Yale University, New Haven, CT 06520, USA.
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17
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Lu-Culligan A, Chavan AR, Vijayakumar P, Irshaid L, Courchaine EM, Milano KM, Tang Z, Pope SD, Song E, Vogels CBF, Lu-Culligan WJ, Campbell KH, Casanovas-Massana A, Bermejo S, Toothaker JM, Lee HJ, Liu F, Schulz W, Fournier J, Muenker MC, Moore AJ, Konnikova L, Neugebauer KM, Ring A, Grubaugh ND, Ko AI, Morotti R, Guller S, Kliman HJ, Iwasaki A, Farhadian SF. Maternal respiratory SARS-CoV-2 infection in pregnancy is associated with a robust inflammatory response at the maternal-fetal interface. Med 2021; 2:591-610.e10. [PMID: 33969332 PMCID: PMC8084634 DOI: 10.1016/j.medj.2021.04.016] [Citation(s) in RCA: 79] [Impact Index Per Article: 26.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2020] [Revised: 02/01/2021] [Accepted: 04/16/2021] [Indexed: 12/19/2022]
Abstract
BACKGROUND Pregnant women are at increased risk for severe outcomes from coronavirus disease 2019 (COVID-19), but the pathophysiology underlying this increased morbidity and its potential effect on the developing fetus is not well understood. METHODS We assessed placental histology, ACE2 expression, and viral and immune dynamics at the term placenta in pregnant women with and without respiratory severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. FINDINGS The majority (13 of 15) of placentas analyzed had no detectable viral RNA. ACE2 was detected by immunohistochemistry in syncytiotrophoblast cells of the normal placenta during early pregnancy but was rarely seen in healthy placentas at full term, suggesting that low ACE2 expression may protect the term placenta from viral infection. Using immortalized cell lines and primary isolated placental cells, we found that cytotrophoblasts, the trophoblast stem cells and precursors to syncytiotrophoblasts, rather than syncytiotrophoblasts or Hofbauer cells, are most vulnerable to SARS-CoV-2 infection in vitro. To better understand potential immune mechanisms shielding placental cells from infection in vivo, we performed bulk and single-cell transcriptomics analyses and found that the maternal-fetal interface of SARS-CoV-2-infected women exhibited robust immune responses, including increased activation of natural killer (NK) and T cells, increased expression of interferon-related genes, as well as markers associated with pregnancy complications such as preeclampsia. CONCLUSIONS SARS-CoV-2 infection in late pregnancy is associated with immune activation at the maternal-fetal interface even in the absence of detectable local viral invasion. FUNDING NIH (T32GM007205, F30HD093350, K23MH118999, R01AI157488, U01DA040588) and Fast Grant funding support from Emergent Ventures at the Mercatus Center.
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Affiliation(s)
- Alice Lu-Culligan
- Department of Immunobiology, Yale School of Medicine, New Haven, CT, USA
| | - Arun R Chavan
- Department of Immunobiology, Yale School of Medicine, New Haven, CT, USA
| | - Pavithra Vijayakumar
- Department of Obstetrics, Gynecology, and Reproductive Sciences, Yale School of Medicine, New Haven, CT, USA
| | - Lina Irshaid
- Department of Pathology, Yale School of Medicine, New Haven, CT, USA
| | - Edward M Courchaine
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA
- Department of Cell Biology, Yale School of Medicine, New Haven, CT, USA
| | - Kristin M Milano
- Department of Obstetrics, Gynecology, and Reproductive Sciences, Yale School of Medicine, New Haven, CT, USA
| | - Zhonghua Tang
- Department of Obstetrics, Gynecology, and Reproductive Sciences, Yale School of Medicine, New Haven, CT, USA
| | - Scott D Pope
- Department of Immunobiology, Yale School of Medicine, New Haven, CT, USA
| | - Eric Song
- Department of Immunobiology, Yale School of Medicine, New Haven, CT, USA
| | - Chantal B F Vogels
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, CT, USA
| | - William J Lu-Culligan
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA
- Department of Cell Biology, Yale School of Medicine, New Haven, CT, USA
| | - Katherine H Campbell
- Department of Obstetrics, Gynecology, and Reproductive Sciences, Yale School of Medicine, New Haven, CT, USA
| | - Arnau Casanovas-Massana
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, CT, USA
| | - Santos Bermejo
- Section of Pulmonary and Critical Care Medicine, Department of Medicine, Yale School of Medicine, New Haven, CT, USA
| | - Jessica M Toothaker
- Department of Pediatrics, Yale School of Medicine, New Haven, CT, USA
- Department of Immunology, University of Pittsburgh, Pittsburgh, PA, USA
| | - Hannah J Lee
- Department of Immunobiology, Yale School of Medicine, New Haven, CT, USA
| | - Feimei Liu
- Department of Immunobiology, Yale School of Medicine, New Haven, CT, USA
| | - Wade Schulz
- Department of Laboratory Medicine, Yale School of Medicine, New Haven, CT, USA
| | - John Fournier
- Section of Infectious Diseases, Department of Medicine, Yale School of Medicine, New Haven, CT, USA
| | - M Catherine Muenker
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, CT, USA
| | - Adam J Moore
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, CT, USA
| | - Liza Konnikova
- Department of Obstetrics, Gynecology, and Reproductive Sciences, Yale School of Medicine, New Haven, CT, USA
- Department of Pediatrics, Yale School of Medicine, New Haven, CT, USA
| | - Karla M Neugebauer
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA
| | - Aaron Ring
- Department of Immunobiology, Yale School of Medicine, New Haven, CT, USA
| | - Nathan D Grubaugh
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, CT, USA
| | - Albert I Ko
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, CT, USA
| | - Raffaella Morotti
- Department of Pathology, Yale School of Medicine, New Haven, CT, USA
| | - Seth Guller
- Department of Obstetrics, Gynecology, and Reproductive Sciences, Yale School of Medicine, New Haven, CT, USA
| | - Harvey J Kliman
- Department of Obstetrics, Gynecology, and Reproductive Sciences, Yale School of Medicine, New Haven, CT, USA
| | - Akiko Iwasaki
- Department of Immunobiology, Yale School of Medicine, New Haven, CT, USA
- Department of Molecular, Cellular and Developmental Biology, New Haven, CT, USA
- Howard Hughes Medical Institute, Chevy Chase, MD, USA
| | - Shelli F Farhadian
- Section of Infectious Diseases, Department of Medicine, Yale School of Medicine, New Haven, CT, USA
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18
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Gordon JM, Phizicky DV, Neugebauer KM. Nuclear mechanisms of gene expression control: pre-mRNA splicing as a life or death decision. Curr Opin Genet Dev 2021; 67:67-76. [PMID: 33291060 PMCID: PMC8084925 DOI: 10.1016/j.gde.2020.11.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [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: 09/10/2020] [Revised: 10/26/2020] [Accepted: 11/03/2020] [Indexed: 02/06/2023]
Abstract
Thousands of genes produce polyadenylated mRNAs that still contain one or more introns. These transcripts are known as retained intron RNAs (RI-RNAs). In the past 10 years, RI-RNAs have been linked to post-transcriptional alternative splicing in a variety of developmental contexts, but they can also be dead-end products fated for RNA decay. Here we discuss the role of intron retention in shaping gene expression programs, as well as recent evidence suggesting that the biogenesis and fate of RI-RNAs is regulated by nuclear organization. We discuss the possibility that proximity of RNA to nuclear speckles - biomolecular condensates that are highly enriched in splicing factors and other RNA binding proteins - is associated with choices ranging from efficient co-transcriptional splicing, export and stability to regulated post-transcriptional splicing and possible vulnerability to decay.
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Affiliation(s)
- Jackson M Gordon
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, 06520, USA
| | - David V Phizicky
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, 06520, USA
| | - Karla M Neugebauer
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, 06520, USA.
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19
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Schärfen L, Neugebauer KM. Transcription Regulation Through Nascent RNA Folding. J Mol Biol 2021; 433:166975. [PMID: 33811916 DOI: 10.1016/j.jmb.2021.166975] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Revised: 03/23/2021] [Accepted: 03/24/2021] [Indexed: 12/14/2022]
Abstract
Folding of RNA into secondary structures through intramolecular base pairing determines an RNA's three-dimensional architecture and associated function. Simple RNA structures like stem loops can provide specialized functions independent of coding capacity, such as protein binding, regulation of RNA processing and stability, stimulation or inhibition of translation. RNA catalysis is dependent on tertiary structures found in the ribosome, tRNAs and group I and II introns. While the extent to which non-coding RNAs contribute to cellular maintenance is generally appreciated, the fact that both non-coding and coding RNA can assume relevant structural states has only recently gained attention. In particular, the co-transcriptional folding of nascent RNA of all classes has the potential to regulate co-transcriptional processing, RNP (ribonucleoprotein particle) formation, and transcription itself. Riboswitches are established examples of co-transcriptionally folded coding RNAs that directly regulate transcription, mainly in prokaryotes. Here we discuss recent studies in both prokaryotes and eukaryotes showing that structure formation may carry a more widespread regulatory logic during RNA synthesis. Local structures forming close to the catalytic center of RNA polymerases have the potential to regulate transcription by reducing backtracking. In addition, stem loops or more complex structures may alter co-transcriptional RNA processing or its efficiency. Several examples of functional structures have been identified to date, and this review provides an overview of physiologically distinct processes where co-transcriptionally folded RNA plays a role. Experimental approaches such as single-molecule FRET and in vivo structural probing to further advance our insight into the significance of co-transcriptional structure formation are discussed.
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Affiliation(s)
- Leonard Schärfen
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520, USA
| | - Karla M Neugebauer
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520, USA.
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20
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Lu-Culligan A, Chavan AR, Vijayakumar P, Irshaid L, Courchaine EM, Milano KM, Tang Z, Pope SD, Song E, Vogels CB, Lu-Culligan WJ, Campbell KH, Casanovas-Massana A, Bermejo S, Toothaker JM, Lee HJ, Liu F, Schulz W, Fournier J, Muenker MC, Moore AJ, Konnikova L, Neugebauer KM, Ring A, Grubaugh ND, Ko AI, Morotti R, Guller S, Kliman HJ, Iwasaki A, Farhadian SF. SARS-CoV-2 infection in pregnancy is associated with robust inflammatory response at the maternal-fetal interface. medRxiv 2021:2021.01.25.21250452. [PMID: 33532791 PMCID: PMC7852242 DOI: 10.1101/2021.01.25.21250452] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [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: 01/21/2023]
Abstract
Pregnant women appear to be at increased risk for severe outcomes associated with COVID-19, but the pathophysiology underlying this increased morbidity and its potential impact on the developing fetus is not well understood. In this study of pregnant women with and without COVID-19, we assessed viral and immune dynamics at the placenta during maternal SARS-CoV-2 infection. Amongst uninfected women, ACE2 was detected by immunohistochemistry in syncytiotrophoblast cells of the normal placenta during early pregnancy but was rarely seen in healthy placentas at full term. Term placentas from women infected with SARS-CoV-2, however, displayed a significant increase in ACE2 levels. Using immortalized cell lines and primary isolated placental cells, we determined the vulnerability of various placental cell types to direct infection by SARS-CoV-2 in vitro. Yet, despite the susceptibility of placental cells to SARS-CoV-2 infection, viral RNA was detected in the placentas of only a subset (~13%) of women in this cohort. Through single cell transcriptomic analyses, we found that the maternal-fetal interface of SARS-CoV-2-infected women exhibited markers associated with pregnancy complications, such as preeclampsia, and robust immune responses, including increased activation of placental NK and T cells and increased expression of interferon-related genes. Overall, this study suggests that SARS-CoV-2 is associated with immune activation at the maternal-fetal interface even in the absence of detectable local viral invasion. While this likely represents a protective mechanism shielding the placenta from infection, inflammatory changes in the placenta may also contribute to poor pregnancy outcomes and thus warrant further investigation.
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Affiliation(s)
- Alice Lu-Culligan
- Department of Immunobiology, Yale School of Medicine, New Haven, CT, USA
| | - Arun R. Chavan
- Department of Immunobiology, Yale School of Medicine, New Haven, CT, USA
| | - Pavithra Vijayakumar
- Department of Obstetrics, Gynecology, and Reproductive Sciences, Yale School of Medicine, New Haven, CT, USA
| | - Lina Irshaid
- Department of Pathology, Yale School of Medicine, New Haven, CT, USA
| | - Edward M. Courchaine
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA
- Department of Cell Biology, Yale School of Medicine, New Haven, CT, USA
| | - Kristin M. Milano
- Department of Obstetrics, Gynecology, and Reproductive Sciences, Yale School of Medicine, New Haven, CT, USA
| | - Zhonghua Tang
- Department of Obstetrics, Gynecology, and Reproductive Sciences, Yale School of Medicine, New Haven, CT, USA
| | - Scott D. Pope
- Department of Immunobiology, Yale School of Medicine, New Haven, CT, USA
| | - Eric Song
- Department of Immunobiology, Yale School of Medicine, New Haven, CT, USA
| | - Chantal B.F. Vogels
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, CT, USA
| | - William J. Lu-Culligan
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA
- Department of Cell Biology, Yale School of Medicine, New Haven, CT, USA
| | - Katherine H. Campbell
- Department of Obstetrics, Gynecology, and Reproductive Sciences, Yale School of Medicine, New Haven, CT, USA
| | - Arnau Casanovas-Massana
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, CT, USA
| | - Santos Bermejo
- Section of Pulmonary and Critical Care Medicine, Department of Medicine, Yale School of Medicine, New Haven, CT, USA
| | - Jessica M. Toothaker
- Department of Pediatrics, Yale School of Medicine, New Haven, CT, USA
- Department of Immunology, University of Pittsburgh, Pittsburgh, PA, USA
| | - Hannah J. Lee
- Department of Immunobiology, Yale School of Medicine, New Haven, CT, USA
| | - Feimei Liu
- Department of Immunobiology, Yale School of Medicine, New Haven, CT, USA
| | - Wade Schulz
- Department of Laboratory Medicine, Yale School of Medicine, New Haven, CT, USA
| | - John Fournier
- Section of Infectious Diseases, Department of Medicine, Yale School of Medicine, New Haven, CT, USA
| | - M. Catherine Muenker
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, CT, USA
| | - Adam J. Moore
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, CT, USA
| | | | - Liza Konnikova
- Department of Obstetrics, Gynecology, and Reproductive Sciences, Yale School of Medicine, New Haven, CT, USA
- Department of Pediatrics, Yale School of Medicine, New Haven, CT, USA
| | - Karla M. Neugebauer
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA
| | - Aaron Ring
- Department of Immunobiology, Yale School of Medicine, New Haven, CT, USA
| | - Nathan D. Grubaugh
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, CT, USA
| | - Albert I. Ko
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, CT, USA
| | - Raffaella Morotti
- Department of Pathology, Yale School of Medicine, New Haven, CT, USA
| | - Seth Guller
- Department of Obstetrics, Gynecology, and Reproductive Sciences, Yale School of Medicine, New Haven, CT, USA
| | - Harvey J. Kliman
- Department of Obstetrics, Gynecology, and Reproductive Sciences, Yale School of Medicine, New Haven, CT, USA
| | - Akiko Iwasaki
- Department of Immunobiology, Yale School of Medicine, New Haven, CT, USA
- Department of Molecular, Cellular and Developmental Biology, New Haven, CT, USA
- Howard Hughes Medical Institute, Chevy Chase, MD, USA
| | - Shelli F. Farhadian
- Section of Infectious Diseases, Department of Medicine, Yale School of Medicine, New Haven, CT, USA
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21
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Reimer KA, Mimoso CA, Adelman K, Neugebauer KM. Co-transcriptional splicing regulates 3' end cleavage during mammalian erythropoiesis. Mol Cell 2021; 81:998-1012.e7. [PMID: 33440169 DOI: 10.1016/j.molcel.2020.12.018] [Citation(s) in RCA: 85] [Impact Index Per Article: 28.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Revised: 12/07/2020] [Accepted: 12/10/2020] [Indexed: 12/11/2022]
Abstract
Pre-mRNA processing steps are tightly coordinated with transcription in many organisms. To determine how co-transcriptional splicing is integrated with transcription elongation and 3' end formation in mammalian cells, we performed long-read sequencing of individual nascent RNAs and precision run-on sequencing (PRO-seq) during mouse erythropoiesis. Splicing was not accompanied by transcriptional pausing and was detected when RNA polymerase II (Pol II) was within 75-300 nucleotides of 3' splice sites (3'SSs), often during transcription of the downstream exon. Interestingly, several hundred introns displayed abundant splicing intermediates, suggesting that splicing delays can take place between the two catalytic steps. Overall, splicing efficiencies were correlated among introns within the same transcript, and intron retention was associated with inefficient 3' end cleavage. Remarkably, a thalassemia patient-derived mutation introducing a cryptic 3'SS improved both splicing and 3' end cleavage of individual β-globin transcripts, demonstrating functional coupling between the two co-transcriptional processes as a determinant of productive gene output.
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Affiliation(s)
- Kirsten A Reimer
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520, USA
| | - Claudia A Mimoso
- Department of Biological Chemistry and Molecular Pharmacology, Blavatnik Institute, Harvard Medical School, Boston, MA 02115, USA
| | - Karen Adelman
- Department of Biological Chemistry and Molecular Pharmacology, Blavatnik Institute, Harvard Medical School, Boston, MA 02115, USA
| | - Karla M Neugebauer
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520, USA.
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22
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Alpert T, Straube K, Oesterreich FC, Herzel L, Neugebauer KM. Widespread Transcriptional Readthrough Caused by Nab2 Depletion Leads to Chimeric Transcripts with Retained Introns. Cell Rep 2020; 33:108496. [PMID: 33378663 PMCID: PMC7916317 DOI: 10.1016/j.celrep.2020.108496] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
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23
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Alpert T, Straube K, Carrillo Oesterreich F, Herzel L, Neugebauer KM. Widespread Transcriptional Readthrough Caused by Nab2 Depletion Leads to Chimeric Transcripts with Retained Introns. Cell Rep 2020; 33:108324. [PMID: 33113357 DOI: 10.1016/j.celrep.2020.108324] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Revised: 09/15/2020] [Accepted: 10/07/2020] [Indexed: 01/26/2023] Open
Abstract
Nascent RNA sequencing has revealed that pre-mRNA splicing can occur shortly after introns emerge from RNA polymerase II (RNA Pol II). Differences in co-transcriptional splicing profiles suggest regulation by cis- and/or trans-acting factors. Here, we use single-molecule intron tracking (SMIT) to identify a cohort of regulators by machine learning in budding yeast. Of these, Nab2 displays reduced co-transcriptional splicing when depleted. Unexpectedly, these splicing defects are attributable to aberrant "intrusive" transcriptional readthrough from upstream genes, as revealed by long-read sequencing. Transcripts that originate from the intron-containing gene's own transcription start site (TSS) are efficiently spliced, indicating no direct role of Nab2 in splicing per se. This work highlights the coupling between transcription, splicing, and 3' end formation in the context of gene organization along chromosomes. We conclude that Nab2 is required for proper 3' end processing, which ensures gene-specific control of co-transcriptional RNA processing.
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Affiliation(s)
- Tara Alpert
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520, USA
| | - Korinna Straube
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520, USA
| | | | - Lydia Herzel
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520, USA
| | - Karla M Neugebauer
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520, USA.
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24
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Fauver JR, Petrone ME, Hodcroft EB, Shioda K, Ehrlich HY, Watts AG, Vogels CBF, Brito AF, Alpert T, Muyombwe A, Razeq J, Downing R, Cheemarla NR, Wyllie AL, Kalinich CC, Ott IM, Quick J, Loman NJ, Neugebauer KM, Greninger AL, Jerome KR, Roychoudhury P, Xie H, Shrestha L, Huang ML, Pitzer VE, Iwasaki A, Omer SB, Khan K, Bogoch II, Martinello RA, Foxman EF, Landry ML, Neher RA, Ko AI, Grubaugh ND. Coast-to-Coast Spread of SARS-CoV-2 during the Early Epidemic in the United States. Cell 2020; 181:990-996.e5. [PMID: 32386545 PMCID: PMC7204677 DOI: 10.1016/j.cell.2020.04.021] [Citation(s) in RCA: 240] [Impact Index Per Article: 60.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Revised: 04/05/2020] [Accepted: 04/14/2020] [Indexed: 12/15/2022]
Abstract
The novel coronavirus SARS-CoV-2 was first detected in the Pacific Northwest region of the United States in January 2020, with subsequent COVID-19 outbreaks detected in all 50 states by early March. To uncover the sources of SARS-CoV-2 introductions and patterns of spread within the United States, we sequenced nine viral genomes from early reported COVID-19 patients in Connecticut. Our phylogenetic analysis places the majority of these genomes with viruses sequenced from Washington state. By coupling our genomic data with domestic and international travel patterns, we show that early SARS-CoV-2 transmission in Connecticut was likely driven by domestic introductions. Moreover, the risk of domestic importation to Connecticut exceeded that of international importation by mid-March regardless of our estimated effects of federal travel restrictions. This study provides evidence of widespread sustained transmission of SARS-CoV-2 within the United States and highlights the critical need for local surveillance. Connecticut’s COVID-19 outbreak resulted from multiple domestic virus introductions SARS-CoV-2 genomic data indicate that coast-to-coast spread occurred in the United States Risk of introduction by domestic air travel exceeded international travel in March Restrictions on international travel did not significantly alter risk estimates
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Affiliation(s)
- Joseph R Fauver
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, CT 06510, USA.
| | - Mary E Petrone
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, CT 06510, USA
| | - Emma B Hodcroft
- Biozentrum, University of Basel, 4056 Basel, Switzerland; Swiss Institute of Bioinformatics, 1015 Lausanne, Switzerland
| | - Kayoko Shioda
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, CT 06510, USA
| | - Hanna Y Ehrlich
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, CT 06510, USA
| | | | - Chantal B F Vogels
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, CT 06510, USA
| | - Anderson F Brito
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, CT 06510, USA
| | - Tara Alpert
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06510, USA
| | - Anthony Muyombwe
- Connecticut State Department of Public Health, Hartford, CT 06510, USA
| | - Jafar Razeq
- Connecticut State Department of Public Health, Hartford, CT 06510, USA
| | - Randy Downing
- Connecticut State Department of Public Health, Hartford, CT 06510, USA
| | - Nagarjuna R Cheemarla
- Department of Laboratory Medicine, Yale School of Medicine, New Haven, CT 06510, USA
| | - Anne L Wyllie
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, CT 06510, USA
| | - Chaney C Kalinich
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, CT 06510, USA
| | - Isabel M Ott
- Department of Ecology & Evolutionary Biology, Yale University, New Haven, CT 06510, USA
| | - Joshua Quick
- Institute of Microbiology and Infection, University of Birmingham, Birmingham B15 2TT, UK
| | - Nicholas J Loman
- Institute of Microbiology and Infection, University of Birmingham, Birmingham B15 2TT, UK
| | - Karla M Neugebauer
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06510, USA
| | - Alexander L Greninger
- Department of Laboratory Medicine, University of Washington, Seattle, WA 98195, USA; Vaccine & Infectious Diseases Division, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
| | - Keith R Jerome
- Department of Laboratory Medicine, University of Washington, Seattle, WA 98195, USA; Vaccine & Infectious Diseases Division, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
| | - Pavitra Roychoudhury
- Department of Laboratory Medicine, University of Washington, Seattle, WA 98195, USA; Vaccine & Infectious Diseases Division, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
| | - Hong Xie
- Department of Laboratory Medicine, University of Washington, Seattle, WA 98195, USA
| | - Lasata Shrestha
- Department of Laboratory Medicine, University of Washington, Seattle, WA 98195, USA
| | - Meei-Li Huang
- Department of Laboratory Medicine, University of Washington, Seattle, WA 98195, USA; Vaccine & Infectious Diseases Division, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA
| | - Virginia E Pitzer
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, CT 06510, USA
| | - Akiko Iwasaki
- Department of Immunobiology, Yale University, New Haven, CT 06510, USA; Howard Hughes Medical Institute, Chevy Chase, MD 20815, USA
| | - Saad B Omer
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, CT 06510, USA; Yale Institute of Global Health, Yale University, New Haven, CT 06510, USA; Section of Infectious Diseases, Department of Medicine, Yale School of Medicine, New Haven, CT 06510, USA; Yale School of Nursing, Yale University, New Haven, CT 06510, USA
| | - Kamran Khan
- BlueDot, Toronto, ON M5J 1A7, Canada; Li Ka Shing Knowledge Institute, St. Michael's Hospital, Toronto, ON M5B 1A6, Canada; Section of Infectious Diseases, Department of Medicine, University of Toronto, Toronto, ON M5S 3H2, Canada
| | - Isaac I Bogoch
- Section of Infectious Diseases, Department of Medicine, University of Toronto, Toronto, ON M5S 3H2, Canada
| | - Richard A Martinello
- Section of Infectious Diseases, Department of Medicine, Yale School of Medicine, New Haven, CT 06510, USA; Department of Pediatrics, Yale School of Medicine, New Haven, CT 06510, USA; Department of Infection Prevention, Yale New Haven Health, New Haven, CT 06510, USA
| | - Ellen F Foxman
- Department of Laboratory Medicine, Yale School of Medicine, New Haven, CT 06510, USA; Department of Immunobiology, Yale University, New Haven, CT 06510, USA
| | - Marie L Landry
- Department of Laboratory Medicine, Yale School of Medicine, New Haven, CT 06510, USA; Section of Infectious Diseases, Department of Medicine, Yale School of Medicine, New Haven, CT 06510, USA; Clinical Virology Laboratory, Yale New Haven Health, New Haven, CT 06510, USA
| | - Richard A Neher
- Biozentrum, University of Basel, 4056 Basel, Switzerland; Swiss Institute of Bioinformatics, 1015 Lausanne, Switzerland
| | - Albert I Ko
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, CT 06510, USA
| | - Nathan D Grubaugh
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, CT 06510, USA.
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25
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26
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Fauver JR, Petrone ME, Hodcroft EB, Shioda K, Ehrlich HY, Watts AG, Vogels CBF, Brito AF, Alpert T, Muyombwe A, Razeq J, Downing R, Cheemarla NR, Wyllie AL, Kalinich CC, Ott I, Quick J, Loman NJ, Neugebauer KM, Greninger AL, Jerome KR, Roychoudhury P, Xie H, Shrestha L, Huang ML, Pitzer VE, Iwasaki A, Omer SB, Khan K, Bogoch II, Martinello RA, Foxman EF, Landry ML, Neher RA, Ko AI, Grubaugh ND. Coast-to-coast spread of SARS-CoV-2 in the United States revealed by genomic epidemiology. medRxiv 2020:2020.03.25.20043828. [PMID: 32511630 PMCID: PMC7276058 DOI: 10.1101/2020.03.25.20043828] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/20/2023]
Abstract
Since its emergence and detection in Wuhan, China in late 2019, the novel coronavirus SARS-CoV-2 has spread to nearly every country around the world, resulting in hundreds of thousands of infections to date. The virus was first detected in the Pacific Northwest region of the United States in January, 2020, with subsequent COVID-19 outbreaks detected in all 50 states by early March. To uncover the sources of SARS-CoV-2 introductions and patterns of spread within the U.S., we sequenced nine viral genomes from early reported COVID-19 patients in Connecticut. Our phylogenetic analysis places the majority of these genomes with viruses sequenced from Washington state. By coupling our genomic data with domestic and international travel patterns, we show that early SARS-CoV-2 transmission in Connecticut was likely driven by domestic introductions. Moreover, the risk of domestic importation to Connecticut exceeded that of international importation by mid-March regardless of our estimated impacts of federal travel restrictions. This study provides evidence for widespread, sustained transmission of SARS-CoV-2 within the U.S. and highlights the critical need for local surveillance.
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Affiliation(s)
- Joseph R Fauver
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, CT, 06510, USA
- These authors contributed equally
| | - Mary E Petrone
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, CT, 06510, USA
- These authors contributed equally
| | - Emma B Hodcroft
- Biozentrum, University of Basel, 4056 Basel, Switzerland
- Swiss Institute of Bioinformatics, 1015 Lausanne, Switzerland
- These authors contributed equally
| | - Kayoko Shioda
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, CT, 06510, USA
| | - Hanna Y Ehrlich
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, CT, 06510, USA
| | | | - Chantal B F Vogels
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, CT, 06510, USA
| | - Anderson F Brito
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, CT, 06510, USA
| | - Tara Alpert
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, 06510, USA
| | - Anthony Muyombwe
- Connecticut State Department of Public Health, Hartford, CT, 06510, USA
| | - Jafar Razeq
- Connecticut State Department of Public Health, Hartford, CT, 06510, USA
| | - Randy Downing
- Connecticut State Department of Public Health, Hartford, CT, 06510, USA
| | - Nagarjuna R Cheemarla
- Department of Laboratory Medicine, Yale School of Medicine, New Haven, CT, 06510, USA
| | - Anne L Wyllie
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, CT, 06510, USA
| | - Chaney C Kalinich
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, CT, 06510, USA
| | - Isabel Ott
- Department of Ecology & Evolutionary Biology, Yale University, New Haven, CT, 06510, USA
| | - Joshua Quick
- Institute of Microbiology and Infection, University of Birmingham, Birmingham B15 2TT, UK
| | - Nicholas J Loman
- Institute of Microbiology and Infection, University of Birmingham, Birmingham B15 2TT, UK
| | - Karla M Neugebauer
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, 06510, USA
| | - Alexander L Greninger
- Department of Laboratory Medicine, University of Washington, Seattle, WA, 98195, USA
- Vaccine & Infectious Diseases Division, Fred Hutchinson Cancer Research Center, Seattle, WA, 98109, USA
| | - Keith R Jerome
- Department of Laboratory Medicine, University of Washington, Seattle, WA, 98195, USA
- Vaccine & Infectious Diseases Division, Fred Hutchinson Cancer Research Center, Seattle, WA, 98109, USA
| | - Pavitra Roychoudhury
- Department of Laboratory Medicine, University of Washington, Seattle, WA, 98195, USA
- Vaccine & Infectious Diseases Division, Fred Hutchinson Cancer Research Center, Seattle, WA, 98109, USA
| | - Hong Xie
- Department of Laboratory Medicine, University of Washington, Seattle, WA, 98195, USA
| | - Lasata Shrestha
- Department of Laboratory Medicine, University of Washington, Seattle, WA, 98195, USA
| | - Meei-Li Huang
- Department of Laboratory Medicine, University of Washington, Seattle, WA, 98195, USA
- Vaccine & Infectious Diseases Division, Fred Hutchinson Cancer Research Center, Seattle, WA, 98109, USA
| | - Virginia E Pitzer
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, CT, 06510, USA
| | - Akiko Iwasaki
- Department of Immunobiology, Yale University, New Haven, CT, 06510, USA
- Howard Hughes Medical Institute, Chevy Chase, Maryland 20815, USA
| | - Saad B Omer
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, CT, 06510, USA
- Yale Institute of Global Health, Yale University, New Haven, CT, 06510, USA
- Department of Internal Medicine, Yale School of Medicine, New Haven, CT, 06510, USA
- Yale School of Nursing, Yale University, New Haven, CT, 06510, USA
| | - Kamran Khan
- BlueDot, Toronto, ON, M5J 1A7, Canada
- Li Ka Shing Knowledge Institute, St. Michael's Hospital, Toronto, ON, M5B 1A6,Canada
- Department of Medicine, Division of Infectious Diseases, University of Toronto, Toronto, ON, M5S 3H2, Canada
| | - Isaac I Bogoch
- Department of Medicine, Division of Infectious Diseases, University of Toronto, Toronto, ON, M5S 3H2, Canada
| | - Richard A Martinello
- Department of Pediatrics, Yale School of Medicine, New Haven, CT, 06510, USA
- Department of Internal Medicine, Yale University School of Medicine, New Haven, CT, 06510, USA
- Yale New Haven Health, Department of Infection Prevention, New Haven, CT, 06510, USA
| | - Ellen F Foxman
- Department of Laboratory Medicine, Yale School of Medicine, New Haven, CT, 06510, USA
- Department of Immunobiology, Yale University, New Haven, CT, 06510, USA
| | - Marie L Landry
- Department of Laboratory Medicine, Yale School of Medicine, New Haven, CT, 06510, USA
- Department of Internal Medicine, Yale University School of Medicine, New Haven, CT, 06510, USA
| | - Richard A Neher
- Biozentrum, University of Basel, 4056 Basel, Switzerland
- Swiss Institute of Bioinformatics, 1015 Lausanne, Switzerland
| | - Albert I Ko
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, CT, 06510, USA
| | - Nathan D Grubaugh
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, CT, 06510, USA
- Senior author
- Lead contact
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27
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Rodenfels J, Sartori P, Golfier S, Nagendra K, Neugebauer KM, Howard J. Contribution of increasing plasma membrane to the energetic cost of early zebrafish embryogenesis. Mol Biol Cell 2020; 31:520-526. [PMID: 32049586 PMCID: PMC7202076 DOI: 10.1091/mbc.e19-09-0529] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2019] [Revised: 01/27/2020] [Accepted: 02/07/2020] [Indexed: 12/20/2022] Open
Abstract
How do early embryos allocate the resources stored in the sperm and egg? Recently, we established isothermal calorimetry to measure heat dissipation by living zebra-fish embryos and to estimate the energetics of specific developmental events. During the reductive cleavage divisions, the rate of heat dissipation increases from ∼60 nJ · s-1 at the two-cell stage to ∼90 nJ · s-1 at the 1024-cell stage. Here we ask which cellular process(es) drive this increasing energetic cost. We present evidence that the cost is due to the increase in the total surface area of all the cells of the embryo. First, embryo volume stays constant during the cleavage stage, indicating that the increase is not due to growth. Second, the heat increase is blocked by nocodazole, which inhibits DNA replication, mitosis, and cell division; this suggests some aspect of cell proliferation contributes to these costs. Third, the heat increases in proportion to the total cell surface area rather than total cell number. Fourth, the heat increase falls within the range of the estimated costs of maintaining and assembling plasma membranes and associated proteins. Thus, the increase in total plasma membrane associated with cell proliferation is likely to contribute appreciably to the total energy budget of the embryo.
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Affiliation(s)
- Jonathan Rodenfels
- Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06511
- Marine Biological Laboratory, Woods Hole, MA 02543
| | - Pablo Sartori
- Marine Biological Laboratory, Woods Hole, MA 02543
- Simons Center for Systems Biology, School of Natural Sciences, Institute for Advanced Study, Princeton, NJ 08540
- Center for Studies in Physics and Biology and Laboratory of Living Matter, Rockefeller University, New York, NY 10065
| | - Stefan Golfier
- Marine Biological Laboratory, Woods Hole, MA 02543
- Max Planck Institute Cell of Molecular Cell Biology and Genetics, Dresden, 01307 Germany
| | - Kartikeya Nagendra
- Marine Biological Laboratory, Woods Hole, MA 02543
- Center for Soft Matter Research, Department of Physics, New York University, New York, NY 10003
| | - Karla M. Neugebauer
- Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06511
- Marine Biological Laboratory, Woods Hole, MA 02543
| | - Jonathon Howard
- Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06511
- Marine Biological Laboratory, Woods Hole, MA 02543
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28
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Abstract
At each active protein-encoding gene, nascent RNA is tethered to the DNA axis by elongating RNA polymerase II (Pol II) and is continuously altered by splicing and other processing events during its synthesis. This review discusses the development of three major methods that enable us to track the conversion of precursor messenger RNA (pre-mRNA) to messenger RNA (mRNA) products in vivo: live-cell imaging, metabolic labeling of RNA, and RNA-seq of purified nascent RNA. These approaches are complementary, addressing distinct issues of transcription rates and intron lifetimes alongside spatial information regarding the gene position of Pol II at which spliceosomes act. The findings will be placed in the context of active transcription units, each of which-because of the presence of nascent RNA, Pol II, and features of the chromatin environment-will recruit a potentially gene-specific constellation of RNA binding proteins and processing machineries.
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Affiliation(s)
- Karla M Neugebauer
- Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06520
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29
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Hochberg-Laufer H, Schwed-Gross A, Neugebauer KM, Shav-Tal Y. Uncoupling of nucleo-cytoplasmic RNA export and localization during stress. Nucleic Acids Res 2019; 47:4778-4797. [PMID: 30864659 PMCID: PMC6511838 DOI: 10.1093/nar/gkz168] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Revised: 02/26/2019] [Accepted: 03/02/2019] [Indexed: 12/25/2022] Open
Abstract
Eukaryotic cells contain sub-cellular compartments that are not membrane bound. Some structures are always present, such as nuclear speckles that contain RNA-binding proteins (RBPs) and poly(A)+ RNAs. Others, like cytoplasmic stress granules (SGs) that harbor mRNAs and RBPs, are induced upon stress. When we examined the formation and composition of nuclear speckles during stress induction with tubercidin, an adenosine analogue previously shown to affect nuclear speckle composition, we unexpectedly found that it also led to the formation of SGs and to the inhibition of several crucial steps of RNA metabolism in cells, thereby serving as a potent inhibitor of the gene expression pathway. Although transcription and splicing persisted under this stress, RBPs and mRNAs were mislocalized in the nucleus and cytoplasm. Specifically, lncRNA and RBP localization to nuclear speckles was disrupted, exon junction complex (EJC) recruitment to mRNA was reduced, mRNA export was obstructed, and cytoplasmic poly(A)+ RNAs localized in SGs. Furthermore, nuclear proteins that participate in mRNA export, such as nucleoporins and mRNA export adaptors, were mislocalized to SGs. This study reveals structural aspects of granule assembly in cells, and describes how the flow of RNA from the nucleus to the cytoplasm is severed under stress.
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Affiliation(s)
- Hodaya Hochberg-Laufer
- The Mina & Everard Goodman Faculty of Life Sciences & Institute of Nanotechnology, Bar-Ilan University, Ramat Gan 5290002, Israel
| | - Avital Schwed-Gross
- The Mina & Everard Goodman Faculty of Life Sciences & Institute of Nanotechnology, Bar-Ilan University, Ramat Gan 5290002, Israel
| | - Karla M Neugebauer
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520, USA
| | - Yaron Shav-Tal
- The Mina & Everard Goodman Faculty of Life Sciences & Institute of Nanotechnology, Bar-Ilan University, Ramat Gan 5290002, Israel
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30
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Rodenfels J, Neugebauer KM, Howard J. Heat Oscillations Driven by the Embryonic Cell Cycle Reveal the Energetic Costs of Signaling. Dev Cell 2019; 48:646-658.e6. [PMID: 30713074 DOI: 10.1016/j.devcel.2018.12.024] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2018] [Revised: 10/31/2018] [Accepted: 12/28/2018] [Indexed: 12/18/2022]
Abstract
All living systems function out of equilibrium and exchange energy in the form of heat with their environment. Thus, heat flow can inform on the energetic costs of cellular processes, which are largely unknown. Here, we have repurposed an isothermal calorimeter to measure heat flow between developing zebrafish embryos and the surrounding medium. Heat flow increased over time with cell number. Unexpectedly, a prominent oscillatory component of the heat flow, with periods matching the synchronous early reductive cleavage divisions, persisted even when DNA synthesis and mitosis were blocked by inhibitors. Instead, the heat flow oscillations were driven by the phosphorylation and dephosphorylation reactions catalyzed by the cell-cycle oscillator, the biochemical network controlling mitotic entry and exit. We propose that the high energetic cost of cell-cycle signaling reflects the significant thermodynamic burden of imposing accurate and robust timing on cell proliferation during development.
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Affiliation(s)
- Jonathan Rodenfels
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520, USA.
| | - Karla M Neugebauer
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520, USA.
| | - Jonathon Howard
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520, USA
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31
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Abstract
Eukaryotic gene expression requires the cumulative activity of multiple molecular machines to synthesize and process newly transcribed pre-messenger RNA. Introns, the noncoding regions in pre-mRNA, must be removed by the spliceosome, which assembles on the pre-mRNA as it is transcribed by RNA polymerase II (Pol II). The assembly and activity of the spliceosome can be modulated by features including the speed of transcription elongation, chromatin, post-translational modifications of Pol II and histone tails, and other RNA processing events like 5'-end capping. Here, we review recent work that has revealed cooperation and coordination among co-transcriptional processing events and speculate on new avenues of research. We anticipate new mechanistic insights capable of unraveling the relative contribution of coupled processing to gene expression.
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Affiliation(s)
- Tucker J Carrocci
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06520, USA
| | - Karla M Neugebauer
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06520, USA
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32
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Affiliation(s)
- Karla M Neugebauer
- a Department of Molecular Biophysics & Biochemistry , Yale University , New Haven , USA
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33
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Abstract
During erythropoiesis, hematopoietic stem and progenitor cells transition to erythroblasts en route to terminal differentiation into enucleated red blood cells. Transcriptome-wide changes underlie distinct morphological and functional characteristics at each cell division during this process. Many studies of gene expression have historically been carried out in erythroblasts, and the biogenesis of β-globin mRNA—the most highly expressed transcript in erythroblasts—was the focus of many seminal studies on the mechanisms of pre-mRNA splicing. We now understand that pre-mRNA splicing plays an important role in shaping the transcriptome of developing erythroblasts. Recent advances have provided insight into the role of alternative splicing and intron retention as important regulatory mechanisms of erythropoiesis. However, dysregulation of splicing during erythropoiesis is also a cause of several hematological diseases, including β-thalassemia and myelodysplastic syndromes. With a growing understanding of the role that splicing plays in these diseases, we are well poised to develop gene-editing treatments. In this review, we focus on changes in the developing erythroblast transcriptome caused by alternative splicing, the molecular basis of splicing-related blood diseases, and therapeutic advances in disease treatment using CRISPR/Cas9 gene editing.
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Affiliation(s)
- Kirsten A Reimer
- Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut, 06520, USA
| | - Karla M Neugebauer
- Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut, 06520, USA
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34
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Herzel L, Straube K, Neugebauer KM. Long-read sequencing of nascent RNA reveals coupling among RNA processing events. Genome Res 2018; 28:1008-1019. [PMID: 29903723 PMCID: PMC6028129 DOI: 10.1101/gr.232025.117] [Citation(s) in RCA: 62] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2017] [Accepted: 05/24/2018] [Indexed: 12/13/2022]
Abstract
Pre-mRNA splicing is accomplished by the spliceosome, a megadalton complex that assembles de novo on each intron. Because spliceosome assembly and catalysis occur cotranscriptionally, we hypothesized that introns are removed in the order of their transcription in genomes dominated by constitutive splicing. Remarkably little is known about splicing order and the regulatory potential of nascent transcript remodeling by splicing, due to the limitations of existing methods that focus on analysis of mature splicing products (mRNAs) rather than substrates and intermediates. Here, we overcome this obstacle through long-read RNA sequencing of nascent, multi-intron transcripts in the fission yeast Schizosaccharomyces pombe. Most multi-intron transcripts were fully spliced, consistent with rapid cotranscriptional splicing. However, an unexpectedly high proportion of transcripts were either fully spliced or fully unspliced, suggesting that splicing of any given intron is dependent on the splicing status of other introns in the transcript. Supporting this, mild inhibition of splicing by a temperature-sensitive mutation in prp2, the homolog of vertebrate U2AF65, increased the frequency of fully unspliced transcripts. Importantly, fully unspliced transcripts displayed transcriptional read-through at the polyA site and were degraded cotranscriptionally by the nuclear exosome. Finally, we show that cellular mRNA levels were reduced in genes with a high number of unspliced nascent transcripts during caffeine treatment, showing regulatory significance of cotranscriptional splicing. Therefore, overall splicing of individual nascent transcripts, 3′ end formation, and mRNA half-life depend on the splicing status of neighboring introns, suggesting crosstalk among spliceosomes and the polyA cleavage machinery during transcription elongation.
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Affiliation(s)
- Lydia Herzel
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06520, USA
| | - Korinna Straube
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06520, USA
| | - Karla M Neugebauer
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06520, USA
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35
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Abstract
Nuclear bodies are RNA-rich membraneless organelles in the cell nucleus that concentrate specific sets of nuclear proteins and RNA-protein complexes. Nuclear bodies such as the nucleolus, Cajal body (CB), and the histone locus body (HLB) concentrate factors required for nuclear steps of RNA processing. Formation of these nuclear bodies occurs on genomic loci and is frequently associated with active sites of transcription. Whether nuclear body formation is dependent on a particular gene element, an active process such as transcription, or the nascent RNA present at gene loci is a topic of debate. Recently, this question has been addressed through studies in model organisms and their embryos. The switch from maternally provided RNA and protein to zygotic gene products in early embryos has been well characterized in a variety of organisms. This process, termed maternal-to-zygotic transition, provides an excellent model for studying formation of nuclear bodies before, during, and after the transcriptional activation of the zygotic genome. Here, we review findings in embryos that reveal key principles in the study of the formation and function of nucleoli, CBs, and HLBs. We propose that while particular gene elements may contribute to formation of these nuclear bodies, active transcription promotes maturation of nuclear bodies and efficient RNA processing within them.
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Affiliation(s)
- Dahyana Arias Escayola
- Molecular Biophysics and Biochemistry , Yale University , New Haven , Connecticut 06520-8114 , United States
| | - Karla M Neugebauer
- Molecular Biophysics and Biochemistry , Yale University , New Haven , Connecticut 06520-8114 , United States
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36
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Courchaine EM, Neugebauer KM. Are Cajal Bodies Droplet Organelles? Biophys J 2018. [DOI: 10.1016/j.bpj.2017.11.2434] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022] Open
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37
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Abstract
Following fertilization, embryos develop for a substantial amount of time with a transcriptionally silent genome. Thus, early development is maternally programmed, as it solely relies on RNAs and proteins that are provided by the female gamete. However, these maternal instructions are not sufficient to support later steps of embryogenesis and are therefore gradually replaced by novel products synthesized from the zygotic genome. This switch in the origin of molecular players that drive early development is known as the maternal-to-zygotic transition (MZT). MZT is a universal phenomenon among all metazoans and comprises two interconnected processes: maternal mRNA degradation and the transcriptional awakening of the zygotic genome. The recent adaptation of high-throughput methods for use in embryos has deepened our knowledge of the molecular principles underlying MZT. These mechanisms comprise conserved strategies for RNA regulation that operate in many well-studied cellular contexts but that have adapted differently to early development. In this Review, we will discuss advances in our understanding of post-transcriptional regulatory pathways that drive maternal mRNA clearance during MZT, with an emphasis on recent data in zebrafish embryos on codon-mediated mRNA decay, the contributions of microRNAs (miRNAs) and RNA-binding proteins to this process, and the roles of RNA modifications in the stability control of maternal mRNAs.
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Affiliation(s)
- Vladimir Despic
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520, USA
- Department of Pharmacology, Weill Medical College, Cornell University, New York, NY 10065, USA
| | - Karla M. Neugebauer
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520, USA
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38
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Brugiolo M, Botti V, Liu N, Müller-McNicoll M, Neugebauer KM. Fractionation iCLIP detects persistent SR protein binding to conserved, retained introns in chromatin, nucleoplasm and cytoplasm. Nucleic Acids Res 2017; 45:10452-10465. [PMID: 28977534 PMCID: PMC5737842 DOI: 10.1093/nar/gkx671] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2016] [Accepted: 07/20/2017] [Indexed: 01/25/2023] Open
Abstract
RNA binding proteins (RBPs) regulate the lives of all RNAs from transcription, processing, and function to decay. How RNA-protein interactions change over time and space to support these roles is poorly understood. Towards this end, we sought to determine how two SR proteins-SRSF3 and SRSF7, regulators of pre-mRNA splicing, nuclear export and translation-interact with RNA in different cellular compartments. To do so, we developed Fractionation iCLIP (Fr-iCLIP), in which chromatin, nucleoplasmic and cytoplasmic fractions are prepared from UV-crosslinked cells and then subjected to iCLIP. As expected, SRSF3 and SRSF7 targets were detected in all fractions, with intron, snoRNA and lncRNA interactions enriched in the nucleus. Cytoplasmically-bound mRNAs reflected distinct functional groupings, suggesting coordinated translation regulation. Surprisingly, hundreds of cytoplasmic intron targets were detected. These cytoplasmic introns were found to be highly conserved and introduced premature termination codons into coding regions. However, many intron-retained mRNAs were not substrates for nonsense-mediated decay (NMD), even though they were detected in polysomes. These findings suggest that intron-retained mRNAs in the cytoplasm have previously uncharacterized functions and/or escape surveillance. Hence, Fr-iCLIP detects the cellular location of RNA-protein interactions and provides insight into co-transcriptional, post-transcriptional and cytoplasmic RBP functions for coding and non-coding RNAs.
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Affiliation(s)
- Mattia Brugiolo
- Department of Molecular Biophysics and Biochemistry, Yale University, 333 Cedar St., New Haven, CT 06520, USA
| | - Valentina Botti
- Department of Molecular Biophysics and Biochemistry, Yale University, 333 Cedar St., New Haven, CT 06520, USA
| | - Na Liu
- Department of Molecular Biophysics and Biochemistry, Yale University, 333 Cedar St., New Haven, CT 06520, USA
| | - Michaela Müller-McNicoll
- RNA Regulation Group, Cluster of Excellence 'Macromolecular Complexes', Goethe-University Frankfurt, Institute of Cell Biology and Neuroscience, Max-von-Laue-Str. 13, 60438 Frankfurt/Main, Germany
| | - Karla M Neugebauer
- Department of Molecular Biophysics and Biochemistry, Yale University, 333 Cedar St., New Haven, CT 06520, USA
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39
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Herzel L, Ottoz DSM, Alpert T, Neugebauer KM. Splicing and transcription touch base: co-transcriptional spliceosome assembly and function. Nat Rev Mol Cell Biol 2017; 18:637-650. [PMID: 28792005 DOI: 10.1038/nrm.2017.63] [Citation(s) in RCA: 207] [Impact Index Per Article: 29.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Several macromolecular machines collaborate to produce eukaryotic messenger RNA. RNA polymerase II (Pol II) translocates along genes that are up to millions of base pairs in length and generates a flexible RNA copy of the DNA template. This nascent RNA harbours introns that are removed by the spliceosome, which is a megadalton ribonucleoprotein complex that positions the distant ends of the intron into its catalytic centre. Emerging evidence that the catalytic spliceosome is physically close to Pol II in vivo implies that transcription and splicing occur on similar timescales and that the transcription and splicing machineries may be spatially constrained. In this Review, we discuss aspects of spliceosome assembly, transcription elongation and other co-transcriptional events that allow the temporal coordination of co-transcriptional splicing.
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Affiliation(s)
- Lydia Herzel
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06520, USA.,Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA
| | - Diana S M Ottoz
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06520, USA
| | - Tara Alpert
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06520, USA
| | - Karla M Neugebauer
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06520, USA
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40
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Despic V, Dejung M, Butter F, Neugebauer KM. Analysis of RNA-protein interactions in vertebrate embryos using UV crosslinking approaches. Methods 2017; 126:44-53. [DOI: 10.1016/j.ymeth.2017.07.013] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2017] [Revised: 06/15/2017] [Accepted: 07/15/2017] [Indexed: 02/06/2023] Open
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41
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Botti V, McNicoll F, Steiner MC, Richter FM, Solovyeva A, Wegener M, Schwich OD, Poser I, Zarnack K, Wittig I, Neugebauer KM, Müller-McNicoll M. Cellular differentiation state modulates the mRNA export activity of SR proteins. J Cell Biol 2017; 216:1993-2009. [PMID: 28592444 PMCID: PMC5496613 DOI: 10.1083/jcb.201610051] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2016] [Revised: 03/22/2017] [Accepted: 04/24/2017] [Indexed: 01/22/2023] Open
Abstract
SR proteins connect nuclear pre-mRNA processing to mRNA export and translation. Botti et al. develop a quantitative nucleocytoplasmic shuttling assay and show that SR proteins are differentially modified and active in differentiated and pluripotent cells. SR proteins function in nuclear pre-mRNA processing, mRNA export, and translation. To investigate their cellular dynamics, we developed a quantitative assay, which detects differences in nucleocytoplasmic shuttling among seven canonical SR protein family members. As expected, SRSF2 and SRSF5 shuttle poorly in HeLa cells but surprisingly display considerable shuttling in pluripotent murine P19 cells. Combining individual-resolution cross-linking and immunoprecipitation (iCLIP) and mass spectrometry, we show that elevated arginine methylation of SRSF5 and lower phosphorylation levels of cobound SRSF2 enhance shuttling of SRSF5 in P19 cells by modulating protein–protein and protein–RNA interactions. Moreover, SRSF5 is bound to pluripotency-specific transcripts such as Lin28a and Pou5f1/Oct4 in the cytoplasm. SRSF5 depletion reduces and overexpression increases their cytoplasmic mRNA levels, suggesting that enhanced mRNA export by SRSF5 is required for the expression of pluripotency factors. Remarkably, neural differentiation of P19 cells leads to dramatically reduced SRSF5 shuttling. Our findings indicate that posttranslational modification of SR proteins underlies the regulation of their mRNA export activities and distinguishes pluripotent from differentiated cells.
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Affiliation(s)
- Valentina Botti
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT
| | - François McNicoll
- Cluster of Excellence Macromolecular Complexes, Institute of Cell Biology and Neuroscience, Goethe University Frankfurt, Frankfurt am Main, Germany
| | - Michaela C Steiner
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany
| | - Florian M Richter
- Functional Proteomics Group, Institute for Biochemistry I, Goethe University Frankfurt, Frankfurt am Main, Germany
| | - Anfisa Solovyeva
- Cluster of Excellence Macromolecular Complexes, Institute of Cell Biology and Neuroscience, Goethe University Frankfurt, Frankfurt am Main, Germany
| | - Marius Wegener
- Cluster of Excellence Macromolecular Complexes, Institute of Cell Biology and Neuroscience, Goethe University Frankfurt, Frankfurt am Main, Germany.,Buchmann Institute for Molecular Life Sciences, Frankfurt am Main, Germany
| | - Oliver D Schwich
- Cluster of Excellence Macromolecular Complexes, Institute of Cell Biology and Neuroscience, Goethe University Frankfurt, Frankfurt am Main, Germany.,Buchmann Institute for Molecular Life Sciences, Frankfurt am Main, Germany
| | - Ina Poser
- Max Planck Institute of Molecular Cell Biology and Genetics, Dresden, Germany
| | - Kathi Zarnack
- Buchmann Institute for Molecular Life Sciences, Frankfurt am Main, Germany
| | - Ilka Wittig
- Functional Proteomics Group, Institute for Biochemistry I, Goethe University Frankfurt, Frankfurt am Main, Germany
| | - Karla M Neugebauer
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT
| | - Michaela Müller-McNicoll
- Cluster of Excellence Macromolecular Complexes, Institute of Cell Biology and Neuroscience, Goethe University Frankfurt, Frankfurt am Main, Germany
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42
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Despic V, Dejung M, Gu M, Krishnan J, Zhang J, Herzel L, Straube K, Gerstein MB, Butter F, Neugebauer KM. Dynamic RNA-protein interactions underlie the zebrafish maternal-to-zygotic transition. Genome Res 2017; 27:1184-1194. [PMID: 28381614 PMCID: PMC5495070 DOI: 10.1101/gr.215954.116] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2016] [Accepted: 03/24/2017] [Indexed: 12/21/2022]
Abstract
During the maternal-to-zygotic transition (MZT), transcriptionally silent embryos rely on post-transcriptional regulation of maternal mRNAs until zygotic genome activation (ZGA). RNA-binding proteins (RBPs) are important regulators of post-transcriptional RNA processing events, yet their identities and functions during developmental transitions in vertebrates remain largely unexplored. Using mRNA interactome capture, we identified 227 RBPs in zebrafish embryos before and during ZGA, hereby named the zebrafish MZT mRNA-bound proteome. This protein constellation consists of many conserved RBPs, some of which are potential stage-specific mRNA interactors that likely reflect the dynamics of RNA-protein interactions during MZT. The enrichment of numerous splicing factors like hnRNP proteins before ZGA was surprising, because maternal mRNAs were found to be fully spliced. To address potentially unique roles of these RBPs in embryogenesis, we focused on Hnrnpa1. iCLIP and subsequent mRNA reporter assays revealed a function for Hnrnpa1 in the regulation of poly(A) tail length and translation of maternal mRNAs through sequence-specific association with 3' UTRs before ZGA. Comparison of iCLIP data from two developmental stages revealed that Hnrnpa1 dissociates from maternal mRNAs at ZGA and instead regulates the nuclear processing of pri-mir-430 transcripts, which we validated experimentally. The shift from cytoplasmic to nuclear RNA targets was accompanied by a dramatic translocation of Hnrnpa1 and other pre-mRNA splicing factors to the nucleus in a transcription-dependent manner. Thus, our study identifies global changes in RNA-protein interactions during vertebrate MZT and shows that Hnrnpa1 RNA-binding activities are spatially and temporally coordinated to regulate RNA metabolism during early development.
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Affiliation(s)
- Vladimir Despic
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06520, USA
| | - Mario Dejung
- Institute of Molecular Biology, 55128 Mainz, Germany
| | - Mengting Gu
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06520, USA.,Program in Computational Biology and Bioinformatics, Yale University, New Haven, Connecticut 06520, USA
| | - Jayanth Krishnan
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06520, USA.,Program in Computational Biology and Bioinformatics, Yale University, New Haven, Connecticut 06520, USA
| | - Jing Zhang
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06520, USA.,Program in Computational Biology and Bioinformatics, Yale University, New Haven, Connecticut 06520, USA
| | - Lydia Herzel
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06520, USA
| | - Korinna Straube
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06520, USA
| | - Mark B Gerstein
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06520, USA.,Program in Computational Biology and Bioinformatics, Yale University, New Haven, Connecticut 06520, USA
| | - Falk Butter
- Institute of Molecular Biology, 55128 Mainz, Germany
| | - Karla M Neugebauer
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06520, USA
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43
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Abstract
Early embryonic development in all known metazoans is characterized by a transcriptionally silent phase, during which development is under control of maternally loaded protein and RNA. The zygotic genome becomes transcriptionally active after a series of rapid reductive cleavage divisions. In this chapter, we present a method to metabolically label, purify, and analyze newly transcribed RNAs in early zebrafish embryos. We previously used this method, which is adaptable to other embryos and systems, to determine the onset of zygotic transcription activation and identify the first zygotic transcripts.
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Affiliation(s)
- Patricia Heyn
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstrasse 108, 01307, Dresden, Germany.
- MRC Human Genetics Unit, IGMM, University of Edinburgh, Edinburgh, EH4 2XU, UK.
| | - Karla M Neugebauer
- Molecular Biophysics & Biochemistry, Yale University, 333 Cedar St, New Haven, CT, 06520, USA.
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44
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Alpert T, Herzel L, Neugebauer KM. Perfect timing: splicing and transcription rates in living cells. Wiley Interdiscip Rev RNA 2016; 8. [PMID: 27873472 DOI: 10.1002/wrna.1401] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/20/2016] [Revised: 09/12/2016] [Accepted: 09/26/2016] [Indexed: 12/27/2022]
Abstract
An important step toward understanding gene regulation is the elucidation of the time necessary for the completion of individual steps. Measurement of reaction rates can reveal potential nodes for regulation. For example, measurements of in vivo transcription elongation rates reveal regulation by DNA sequence, gene architecture, and chromatin. Pre-mRNA splicing is regulated by transcription elongation rates and vice versa, yet the rates of RNA processing reactions remain largely elusive. Since the 1980s, numerous model systems and approaches have been used to determine the precise timing of splicing in vivo. Because splicing can be co-transcriptional, the position of Pol II when splicing is detected has been used as a proxy for time by some investigators. In addition to these 'distance-based' measurements, 'time-based' measurements have been possible through live cell imaging, metabolic labeling of RNA, and gene induction. Yet splicing rates can be convolved by the time it takes for transcription, spliceosome assembly and spliceosome disassembly. The variety of assays and systems used has, perhaps not surprisingly, led to reports of widely differing splicing rates in vivo. Recently, single molecule RNA-seq has indicated that splicing occurs more quickly than previously deduced. Here we comprehensively review these findings and discuss evidence that splicing and transcription rates are closely coordinated, facilitating the efficiency of gene expression. On the other hand, introduction of splicing delays through as yet unknown mechanisms provide opportunity for regulation. More work is needed to understand how cells optimize the rates of gene expression for a range of biological conditions. WIREs RNA 2017, 8:e1401. doi: 10.1002/wrna.1401 For further resources related to this article, please visit the WIREs website.
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Affiliation(s)
- Tara Alpert
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA
| | - Lydia Herzel
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA
| | - Karla M Neugebauer
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA
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45
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Heyn P, Salmonowicz H, Rodenfels J, Neugebauer KM. Activation of transcription enforces the formation of distinct nuclear bodies in zebrafish embryos. RNA Biol 2016; 14:752-760. [PMID: 27858508 DOI: 10.1080/15476286.2016.1255397] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Nuclear bodies are cellular compartments that lack lipid bilayers and harbor specific RNAs and proteins. Recent proposals that nuclear bodies form through liquid-liquid phase separation leave the question of how different nuclear bodies maintain their distinct identities unanswered. Here we investigate Cajal bodies (CBs), histone locus bodies (HLBs) and nucleoli - involved in assembly of the splicing machinery, histone mRNA 3' end processing, and rRNA processing, respectively - in the embryos of the zebrafish, Danio rerio. We take advantage of the transcriptional silence of the 1-cell embryo and follow nuclear body appearance as zygotic transcription becomes activated. CBs are present from fertilization onwards, while HLB and nucleolar components formed foci several hours later when histone genes and rDNA became active. HLB formation was blocked by transcription inhibition, suggesting nascent histone transcripts recruit HLB components like U7 snRNP. Surprisingly, we found that U7 base-pairing with nascent histone transcripts was not required for localization to HLBs. Rather, the type of Sm ring assembled on U7 determined its targeting to HLBs or CBs; the spliceosomal Sm ring targeted snRNAs to CBs while the specialized U7 Sm-ring localized to HLBs, demonstrating the contribution of protein constituents to the distinction among nuclear bodies. Thus, nucleolar, HLB, and CB components can mix in early embryogenesis when transcription is naturally or artificially silenced. These data support a model in which transcription of specific gene loci nucleates nuclear body components with high specificity and fidelity to perform distinct regulatory functions.
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Affiliation(s)
- Patricia Heyn
- a Max Planck Institute of Molecular Cell Biology and Genetics , Dresden , Germany
| | - Hanna Salmonowicz
- a Max Planck Institute of Molecular Cell Biology and Genetics , Dresden , Germany
| | - Jonathan Rodenfels
- b Department of Molecular Biophysics & Biochemistry , Yale University , New Haven , CT , USA
| | - Karla M Neugebauer
- b Department of Molecular Biophysics & Biochemistry , Yale University , New Haven , CT , USA
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46
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Müller-McNicoll M, Botti V, de Jesus Domingues AM, Brandl H, Schwich OD, Steiner MC, Curk T, Poser I, Zarnack K, Neugebauer KM. SR proteins are NXF1 adaptors that link alternative RNA processing to mRNA export. Genes Dev 2016; 30:553-66. [PMID: 26944680 PMCID: PMC4782049 DOI: 10.1101/gad.276477.115] [Citation(s) in RCA: 193] [Impact Index Per Article: 24.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
In this study, Müller-McNicoll et al. investigate how export machinery assembles on mRNA and how it senses mRNA maturity before exporting mRNAs from the nucleus. They show that SR proteins act as NXF1 adaptors by connecting alternative splicing and 3′ end formation to mRNA export in vivo and propose that SR proteins and NXF1 form a ternary complex on mRNAs, particularly in last exons, and shuttle together to the cytoplasm. Nuclear export factor 1 (NXF1) exports mRNA to the cytoplasm after recruitment to mRNA by specific adaptor proteins. How and why cells use numerous different export adaptors is poorly understood. Here we critically evaluate members of the SR protein family (SRSF1–7) for their potential to act as NXF1 adaptors that couple pre-mRNA processing to mRNA export. Consistent with this proposal, >1000 endogenous mRNAs required individual SR proteins for nuclear export in vivo. To address the mechanism, transcriptome-wide RNA-binding profiles of NXF1 and SRSF1–7 were determined in parallel by individual-nucleotide-resolution UV cross-linking and immunoprecipitation (iCLIP). Quantitative comparisons of RNA-binding sites showed that NXF1 and SR proteins bind mRNA targets at adjacent sites, indicative of cobinding. SRSF3 emerged as the most potent NXF1 adaptor, conferring sequence specificity to RNA binding by NXF1 in last exons. Interestingly, SRSF3 and SRSF7 were shown to bind different sites in last exons and regulate 3′ untranslated region length in an opposing manner. Both SRSF3 and SRSF7 promoted NXF1 recruitment to mRNA. Thus, SRSF3 and SRSF7 couple alternative splicing and polyadenylation to NXF1-mediated mRNA export, thereby controlling the cytoplasmic abundance of transcripts with alternative 3′ ends.
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Affiliation(s)
- Michaela Müller-McNicoll
- RNA Regulation Group, Institute of Cell Biology and Neuroscience, Goethe-University Frankfurt, 60438 Frankfurt/Main, Germany
| | - Valentina Botti
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06520, USA
| | | | - Holger Brandl
- Max Planck Institute of Molecular Cell Biology and Genetics, 01307 Dresden, Germany
| | - Oliver D Schwich
- RNA Regulation Group, Institute of Cell Biology and Neuroscience, Goethe-University Frankfurt, 60438 Frankfurt/Main, Germany; Buchmann Institute for Life Sciences (BMLS), 60438 Frankfurt/Main, Germany
| | - Michaela C Steiner
- Max Planck Institute of Molecular Cell Biology and Genetics, 01307 Dresden, Germany
| | - Tomaz Curk
- Faculty of Computer and Information Science, University of Ljubljana, Ljubljana 1000, Slovenia
| | - Ina Poser
- Max Planck Institute of Molecular Cell Biology and Genetics, 01307 Dresden, Germany
| | - Kathi Zarnack
- Buchmann Institute for Life Sciences (BMLS), 60438 Frankfurt/Main, Germany
| | - Karla M Neugebauer
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06520, USA
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Abstract
Cells contain numerous, molecularly distinct cellular compartments that are not enclosed by lipid bilayers. These compartments are implicated in a wide range of cellular activities, and they have been variously described as bodies, granules, or organelles. Recent evidence suggests that a liquid-liquid phase separation (LLPS) process may drive their formation, possibly justifying the unifying term "droplet organelle". A veritable deluge of recent publications points to the importance of low-complexity proteins and RNA in determining the physical properties of phase-separated structures. Many of the proteins linked to such structures are implicated in human diseases, such as amyotrophic lateral sclerosis (ALS). We provide an overview of the organizational principles that characterize putative "droplet organelles" in healthy and diseased cells, connecting protein biochemistry with cell physiology.
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Affiliation(s)
- Edward M Courchaine
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA
| | - Alice Lu
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA
| | - Karla M Neugebauer
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA
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48
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Oesterreich FC, Herzel L, Straube K, Hujer K, Howard J, Neugebauer KM. Splicing of Nascent RNA Coincides with Intron Exit from RNA Polymerase II. Cell 2016; 165:372-381. [PMID: 27020755 PMCID: PMC4826323 DOI: 10.1016/j.cell.2016.02.045] [Citation(s) in RCA: 142] [Impact Index Per Article: 17.8] [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: 12/17/2015] [Revised: 02/04/2016] [Accepted: 02/21/2016] [Indexed: 01/01/2023]
Abstract
Protein-coding genes in eukaryotes are transcribed by RNA polymerase II (Pol II) and introns are removed from pre-mRNA by the spliceosome. Understanding the time lag between Pol II progression and splicing could provide mechanistic insights into the regulation of gene expression. Here, we present two single-molecule nascent RNA sequencing methods that directly determine the progress of splicing catalysis as a function of Pol II position. Endogenous genes were analyzed on a global scale in budding yeast. We show that splicing is 50% complete when Pol II is only 45 nt downstream of introns, with the first spliced products observed as introns emerge from Pol II. Perturbations that slow the rate of spliceosome assembly or speed up the rate of transcription caused splicing delays, showing that regulation of both processes determines in vivo splicing profiles. We propose that matched rates streamline the gene expression pathway, while allowing regulation through kinetic competition.
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Affiliation(s)
| | - Lydia Herzel
- Department of Molecular Biophysics & Biochemistry, Yale University, New Haven, CT 06520, USA
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstraße 108, 01307 Dresden, Germany
| | - Korinna Straube
- Department of Molecular Biophysics & Biochemistry, Yale University, New Haven, CT 06520, USA
| | - Katja Hujer
- Max Planck Institute of Molecular Cell Biology and Genetics, Pfotenhauerstraße 108, 01307 Dresden, Germany
| | - Jonathon Howard
- Department of Molecular Biophysics & Biochemistry, Yale University, New Haven, CT 06520, USA
| | - Karla M. Neugebauer
- Department of Molecular Biophysics & Biochemistry, Yale University, New Haven, CT 06520, USA
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49
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Abstract
Low-complexity proteins undergo phase separation in vitro, forming hydrogels or liquid droplets. Whether these form in vivo, and under what conditions, is still unclear. In this issue, Hennig et al. (2015. J. Cell Biol. http://dx.doi.org/10.1083/jcb.201504117) show that formation of the paraspeckle, a nuclear body that regulates gene expression, requires low-complexity prion-like domains (PLDs) within paraspeckle proteins. The same proteins were shown to form hydrogels, shedding light on the role of “functional aggregation” in nuclear substructure.
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50
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Abstract
Initially identified as a marker of coiled bodies (now Cajal bodies or CBs), the protein coilin was discovered a quarter of century ago. Coilin is now known to scaffold the CB, but its structure and function are poorly understood. Nearly devoid of predicted structural motifs, coilin has numerous reported molecular interactions that must underlie its role in the formation and function of CBs. In this review, we summarize what we have learned in the past 25 years about coilin's structure, post-transcriptional modifications, and interactions with RNA and proteins. We show that genes with homology to human coilin are found in primitive metazoans and comment on differences among model organisms. Coilin's function in Cajal body formation and RNP metabolism will be discussed in the light of these developments.
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Affiliation(s)
- Martin Machyna
- a Department of Molecular Biophysics & Biochemistry ; Yale University ; New Haven , CT USA
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