1
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Guarnacci M, Zhang PH, Kanchi M, Hung YT, Lin H, Shirokikh NE, Yang L, Preiss T. Substrate diversity of NSUN enzymes and links of 5-methylcytosine to mRNA translation and turnover. Life Sci Alliance 2024; 7:e202402613. [PMID: 38986569 PMCID: PMC11235314 DOI: 10.26508/lsa.202402613] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2024] [Revised: 06/28/2024] [Accepted: 06/28/2024] [Indexed: 07/12/2024] Open
Abstract
Maps of the RNA modification 5-methylcytosine (m5C) often diverge markedly not only because of differences in detection methods, data depand analysis pipelines but also biological factors. We re-analysed bisulfite RNA sequencing datasets from five human cell lines and seven tissues using a coherent m5C site calling pipeline. With the resulting union list of 6,393 m5C sites, we studied site distribution, enzymology, interaction with RNA-binding proteins and molecular function. We confirmed tRNA:m5C methyltransferases NSUN2 and NSUN6 as the main mRNA m5C "writers," but further showed that the rRNA:m5C methyltransferase NSUN5 can also modify mRNA. Each enzyme recognises mRNA features that strongly resemble their canonical substrates. By analysing proximity between mRNA m5C sites and footprints of RNA-binding proteins, we identified new candidates for functional interactions, including the RNA helicases DDX3X, involved in mRNA translation, and UPF1, an mRNA decay factor. We found that lack of NSUN2 in HeLa cells affected both steady-state levels of, and UPF1-binding to, target mRNAs. Our studies emphasise the emerging diversity of m5C writers and readers and their effect on mRNA function.
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Affiliation(s)
- Marco Guarnacci
- https://ror.org/019wvm592 Shine-Dalgarno Centre for RNA Innovation, Division of Genome Science and Cancer, John Curtin School of Medical Research, Australian National University, Canberra, Australia
| | - Pei-Hong Zhang
- Shanghai Institute of Nutrition and Health, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai, China
- Center for Molecular Medicine, Children's Hospital, Shanghai Key Laboratory of Medical Epigenetics, International Laboratory of Medical Epigenetics and Metabolism, Institutes of Biomedical Sciences, Fudan University, Shanghai, China
| | - Madhu Kanchi
- https://ror.org/019wvm592 Shine-Dalgarno Centre for RNA Innovation, Division of Genome Science and Cancer, John Curtin School of Medical Research, Australian National University, Canberra, Australia
| | - Yu-Ting Hung
- https://ror.org/019wvm592 Shine-Dalgarno Centre for RNA Innovation, Division of Genome Science and Cancer, John Curtin School of Medical Research, Australian National University, Canberra, Australia
| | - Hanrong Lin
- https://ror.org/019wvm592 Shine-Dalgarno Centre for RNA Innovation, Division of Genome Science and Cancer, John Curtin School of Medical Research, Australian National University, Canberra, Australia
| | - Nikolay E Shirokikh
- https://ror.org/019wvm592 Shine-Dalgarno Centre for RNA Innovation, Division of Genome Science and Cancer, John Curtin School of Medical Research, Australian National University, Canberra, Australia
| | - Li Yang
- Center for Molecular Medicine, Children's Hospital, Shanghai Key Laboratory of Medical Epigenetics, International Laboratory of Medical Epigenetics and Metabolism, Institutes of Biomedical Sciences, Fudan University, Shanghai, China
| | - Thomas Preiss
- https://ror.org/019wvm592 Shine-Dalgarno Centre for RNA Innovation, Division of Genome Science and Cancer, John Curtin School of Medical Research, Australian National University, Canberra, Australia
- Victor Chang Cardiac Research Institute, Sydney, Australia
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2
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Coelho JPL, Yip MCJ, Oltion K, Taunton J, Shao S. The eRF1 degrader SRI-41315 acts as a molecular glue at the ribosomal decoding center. Nat Chem Biol 2024; 20:877-884. [PMID: 38172604 PMCID: PMC11253071 DOI: 10.1038/s41589-023-01521-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2023] [Accepted: 12/04/2023] [Indexed: 01/05/2024]
Abstract
Translation termination is an essential cellular process, which is also of therapeutic interest for diseases that manifest from premature stop codons. In eukaryotes, translation termination requires eRF1, which recognizes stop codons, catalyzes the release of nascent proteins from ribosomes and facilitates ribosome recycling. The small molecule SRI-41315 triggers eRF1 degradation and enhances translational readthrough of premature stop codons. However, the mechanism of action of SRI-41315 on eRF1 and translation is not known. Here we report cryo-EM structures showing that SRI-41315 acts as a metal-dependent molecular glue between the N domain of eRF1 responsible for stop codon recognition and the ribosomal subunit interface near the decoding center. Retention of eRF1 on ribosomes by SRI-41315 leads to ribosome collisions, eRF1 ubiquitylation and a higher frequency of translation termination at near-cognate stop codons. Our findings reveal a new mechanism of release factor inhibition and additional implications for pharmacologically targeting eRF1.
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Affiliation(s)
- João P L Coelho
- Department of Cell Biology, Harvard Medical School, Boston, MA, USA
| | - Matthew C J Yip
- Department of Cell Biology, Harvard Medical School, Boston, MA, USA
| | - Keely Oltion
- Chemistry and Chemical Biology Graduate Program, University of California San Francisco, San Francisco, CA, USA
| | - Jack Taunton
- Department of Cellular and Molecular Pharmacology, University of California San Francisco, San Francisco, CA, USA
| | - Sichen Shao
- Department of Cell Biology, Harvard Medical School, Boston, MA, USA.
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3
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Zhuravskaya A, Yap K, Hamid F, Makeyev EV. Alternative splicing coupled to nonsense-mediated decay coordinates downregulation of non-neuronal genes in developing mouse neurons. Genome Biol 2024; 25:162. [PMID: 38902825 PMCID: PMC11188260 DOI: 10.1186/s13059-024-03305-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2023] [Accepted: 06/07/2024] [Indexed: 06/22/2024] Open
Abstract
BACKGROUND The functional coupling between alternative pre-mRNA splicing (AS) and the mRNA quality control mechanism called nonsense-mediated decay (NMD) can modulate transcript abundance. Previous studies have identified several examples of such a regulation in developing neurons. However, the systems-level effects of AS-NMD in this context are poorly understood. RESULTS We developed an R package, factR2, which offers a comprehensive suite of AS-NMD analysis functions. Using this tool, we conducted a longitudinal analysis of gene expression in pluripotent stem cells undergoing induced neuronal differentiation. Our analysis uncovers hundreds of AS-NMD events with significant potential to regulate gene expression. Notably, this regulation is significantly overrepresented in specific functional groups of developmentally downregulated genes. Particularly strong association with gene downregulation is detected for alternative cassette exons stimulating NMD upon their inclusion into mature mRNA. By combining bioinformatic analyses with CRISPR/Cas9 genome editing and other experimental approaches we show that NMD-stimulating cassette exons regulated by the RNA-binding protein PTBP1 dampen the expression of their genes in developing neurons. We also provided evidence that the inclusion of NMD-stimulating cassette exons into mature mRNAs is temporally coordinated with NMD-independent gene repression mechanisms. CONCLUSIONS Our study provides an accessible workflow for the discovery and prioritization of AS-NMD targets. It further argues that the AS-NMD pathway plays a widespread role in developing neurons by facilitating the downregulation of functionally related non-neuronal genes.
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Affiliation(s)
- Anna Zhuravskaya
- Centre for Developmental Neurobiology, King's College London, London, SE1 1UL, UK
| | - Karen Yap
- Centre for Developmental Neurobiology, King's College London, London, SE1 1UL, UK
| | - Fursham Hamid
- Centre for Developmental Neurobiology, King's College London, London, SE1 1UL, UK.
| | - Eugene V Makeyev
- Centre for Developmental Neurobiology, King's College London, London, SE1 1UL, UK.
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4
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Langer LM, Kurscheidt K, Basquin J, Bonneau F, Iermak I, Basquin C, Conti E. UPF1 helicase orchestrates mutually exclusive interactions with the SMG6 endonuclease and UPF2. Nucleic Acids Res 2024; 52:6036-6048. [PMID: 38709891 PMCID: PMC11162806 DOI: 10.1093/nar/gkae323] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2024] [Revised: 04/06/2024] [Accepted: 04/25/2024] [Indexed: 05/08/2024] Open
Abstract
Nonsense-mediated mRNA decay (NMD) is a conserved co-translational mRNA surveillance and turnover pathway across eukaryotes. NMD has a central role in degrading defective mRNAs and also regulates the stability of a significant portion of the transcriptome. The pathway is organized around UPF1, an RNA helicase that can interact with several NMD-specific factors. In human cells, degradation of the targeted mRNAs begins with a cleavage event that requires the recruitment of the SMG6 endonuclease to UPF1. Previous studies have identified functional links between SMG6 and UPF1, but the underlying molecular mechanisms have remained elusive. Here, we used mass spectrometry, structural biology and biochemical approaches to identify and characterize a conserved short linear motif in SMG6 that interacts with the cysteine/histidine-rich (CH) domain of UPF1. Unexpectedly, we found that the UPF1-SMG6 interaction is precluded when the UPF1 CH domain is engaged with another NMD factor, UPF2. Based on cryo-EM data, we propose that the formation of distinct SMG6-containing and UPF2-containing NMD complexes may be dictated by different conformational states connected to the RNA-binding status of UPF1. Our findings rationalize a key event in metazoan NMD and advance our understanding of mechanisms regulating activity and guiding substrate recognition by the SMG6 endonuclease.
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Affiliation(s)
- Lukas M Langer
- Department of Structural Cell Biology, Max Planck Institute of Biochemistry, Martinsried/Munich D-82152, Germany
| | - Katharina Kurscheidt
- Department of Structural Cell Biology, Max Planck Institute of Biochemistry, Martinsried/Munich D-82152, Germany
| | - Jérôme Basquin
- Department of Structural Cell Biology, Max Planck Institute of Biochemistry, Martinsried/Munich D-82152, Germany
| | - Fabien Bonneau
- Department of Structural Cell Biology, Max Planck Institute of Biochemistry, Martinsried/Munich D-82152, Germany
| | - Iuliia Iermak
- Department of Structural Cell Biology, Max Planck Institute of Biochemistry, Martinsried/Munich D-82152, Germany
| | - Claire Basquin
- Department of Structural Cell Biology, Max Planck Institute of Biochemistry, Martinsried/Munich D-82152, Germany
| | - Elena Conti
- Department of Structural Cell Biology, Max Planck Institute of Biochemistry, Martinsried/Munich D-82152, Germany
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5
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Bensaude O, Barbosa I, Morillo L, Dikstein R, Le Hir H. Exon-junction complex association with stalled ribosomes and slow translation-independent disassembly. Nat Commun 2024; 15:4209. [PMID: 38760352 PMCID: PMC11101648 DOI: 10.1038/s41467-024-48371-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2023] [Accepted: 04/29/2024] [Indexed: 05/19/2024] Open
Abstract
Exon junction complexes are deposited at exon-exon junctions during splicing. They are primarily known to activate non-sense mediated degradation of transcripts harbouring premature stop codons before the last intron. According to a popular model, exon-junction complexes accompany mRNAs to the cytoplasm where the first translating ribosome pushes them out. However, they are also removed by uncharacterized, translation-independent mechanisms. Little is known about kinetic and transcript specificity of these processes. Here we tag core subunits of exon-junction complexes with complementary split nanoluciferase fragments to obtain sensitive and quantitative assays for complex formation. Unexpectedly, exon-junction complexes form large stable mRNPs containing stalled ribosomes. Complex assembly and disassembly rates are determined after an arrest in transcription and/or translation. 85% of newly deposited exon-junction complexes are disassembled by a translation-dependent mechanism. However as this process is much faster than the translation-independent one, only 30% of the exon-junction complexes present in cells at steady state require translation for disassembly. Deep RNA sequencing shows a bias of exon-junction complex bound transcripts towards microtubule and centrosome coding ones and demonstrate that the lifetimes of exon-junction complexes are transcript-specific. This study provides a dynamic vision of exon-junction complexes and uncovers their unexpected stable association with ribosomes.
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Affiliation(s)
- Olivier Bensaude
- Institut de Biologie de l'Ecole Normale Supérieure (IBENS), Ecole Normale Supérieure, CNRS, INSERM, PSL Research University, Paris, France.
| | - Isabelle Barbosa
- Institut de Biologie de l'Ecole Normale Supérieure (IBENS), Ecole Normale Supérieure, CNRS, INSERM, PSL Research University, Paris, France
| | - Lucia Morillo
- Institut de Biologie de l'Ecole Normale Supérieure (IBENS), Ecole Normale Supérieure, CNRS, INSERM, PSL Research University, Paris, France
| | - Rivka Dikstein
- Department of Biomolecular Sciences, The Weizmann Institute of Science, Rehovot, Israel
| | - Hervé Le Hir
- Institut de Biologie de l'Ecole Normale Supérieure (IBENS), Ecole Normale Supérieure, CNRS, INSERM, PSL Research University, Paris, France.
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6
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Pappas CT, Mayfield RM, Dickerson AE, Mi-Mi L, Gregorio CC. Human disease-causing mutations result in loss of leiomodin 2 through nonsense-mediated mRNA decay. PLoS Genet 2024; 20:e1011279. [PMID: 38748723 PMCID: PMC11132695 DOI: 10.1371/journal.pgen.1011279] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2023] [Revised: 05/28/2024] [Accepted: 04/30/2024] [Indexed: 05/30/2024] Open
Abstract
The leiomodin (Lmod) family of actin-binding proteins play a critical role in muscle function, highlighted by the fact that mutations in all three family members (LMOD1-3) result in human myopathies. Mutations in the cardiac predominant isoform, LMOD2 lead to severe neonatal dilated cardiomyopathy. Most of the disease-causing mutations in the LMOD gene family are nonsense, or frameshift, mutations predicted to result in expression of truncated proteins. However, in nearly all cases of disease, little to no LMOD protein is expressed. We show here that nonsense-mediated mRNA decay, a cellular mechanism which eliminates mRNAs with premature termination codons, underlies loss of mutant protein from two independent LMOD2 disease-causing mutations. Furthermore, we generated steric-blocking oligonucleotides that obstruct deposition of the exon junction complex, preventing nonsense-mediated mRNA decay of mutant LMOD2 transcripts, thereby restoring mutant protein expression. Our investigation lays the initial groundwork for potential therapeutic intervention in LMOD-linked myopathies.
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Affiliation(s)
- Christopher T. Pappas
- Department of Cellular and Molecular Medicine and Sarver Molecular Cardiovascular Research Program, University of Arizona, Tucson, Arizona, United States of America
| | - Rachel M. Mayfield
- Department of Cellular and Molecular Medicine and Sarver Molecular Cardiovascular Research Program, University of Arizona, Tucson, Arizona, United States of America
| | - Ava E. Dickerson
- Department of Cellular and Molecular Medicine and Sarver Molecular Cardiovascular Research Program, University of Arizona, Tucson, Arizona, United States of America
| | - Lei Mi-Mi
- Department of Cellular and Molecular Medicine and Sarver Molecular Cardiovascular Research Program, University of Arizona, Tucson, Arizona, United States of America
| | - Carol C. Gregorio
- Department of Cellular and Molecular Medicine and Sarver Molecular Cardiovascular Research Program, University of Arizona, Tucson, Arizona, United States of America
- Department of Medicine and Cardiovascular Research Institute, Icahn School of Medicine at Mount Sinai, New York City, New York, United States of America
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7
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Carvajal-Moreno J, Wang X, Hernandez VA, Mondal M, Zhao X, Yalowich JC, Elton TS. Use of CRISPR/Cas9 with Homology-Directed Repair to Gene-Edit Topoisomerase II β in Human Leukemia K562 Cells: Generation of a Resistance Phenotype. J Pharmacol Exp Ther 2024; 389:186-196. [PMID: 38508753 PMCID: PMC11026151 DOI: 10.1124/jpet.123.002038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2023] [Revised: 02/27/2024] [Accepted: 02/27/2024] [Indexed: 03/22/2024] Open
Abstract
DNA topoisomerase IIβ (TOP2β/180; 180 kDa) is a nuclear enzyme that regulates DNA topology by generation of short-lived DNA double-strand breaks, primarily during transcription. TOP2β/180 can be a target for DNA damage-stabilizing anticancer drugs, whose efficacy is often limited by chemoresistance. Our laboratory previously demonstrated reduced levels of TOP2β/180 (and the paralog TOP2α/170) in an acquired etoposide-resistant human leukemia (K562) clonal cell line, K/VP.5, in part due to overexpression of microRNA-9-3p/5p impacting post-transcriptional events. To evaluate the effect on drug sensitivity upon reduction/elimination of TOP2β/180, a premature stop codon was generated at the TOP2β/180 gene exon 19/intron 19 boundary (AGAA//GTAA→ATAG//GTAA) in parental K562 cells (which contain four TOP2β/180 alleles) by CRISPR/Cas9 editing with homology-directed repair to disrupt production of full-length TOP2β/180. Gene-edited clones were identified and verified by quantitative polymerase chain reaction and Sanger sequencing, respectively. Characterization of TOP2β/180 gene-edited clones, with one or all four TOP2β/180 alleles mutated, revealed partial or complete loss of TOP2β mRNA/protein, respectively. The loss of TOP2β/180 protein correlated with decreased (2-{4-[(7-chloro-2-quinoxalinyl)oxy]phenoxy}propionic acid)-induced DNA damage and partial resistance in growth inhibition assays. Partial resistance to mitoxantrone was also noted in the gene-edited clone with all four TOP2β/180 alleles modified. No cross-resistance to etoposide or mAMSA was noted in the gene-edited clones. Results demonstrated the role of TOP2β/180 in drug sensitivity/resistance in K562 cells and revealed differential paralog activity of TOP2-targeted agents. SIGNIFICANCE STATEMENT: Data indicated that CRISPR/Cas9 editing of the exon 19/intron 19 boundary in the TOP2β/180 gene to introduce a premature stop codon resulted in partial to complete disruption of TOP2β/180 expression in human leukemia (K562) cells depending on the number of edited alleles. Edited clones were partially resistant to mitoxantrone and XK469, while lacking resistance to etoposide and mAMSA. Results demonstrated the import of TOP2β/180 in drug sensitivity/resistance in K562 cells and revealed differential paralog activity of TOP2-targeted agents.
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Affiliation(s)
- Jessika Carvajal-Moreno
- Division of Pharmaceutics and Pharmacology, College of Pharmacy, The Ohio State University, Columbus, Ohio
| | - Xinyi Wang
- Division of Pharmaceutics and Pharmacology, College of Pharmacy, The Ohio State University, Columbus, Ohio
| | - Victor A Hernandez
- Division of Pharmaceutics and Pharmacology, College of Pharmacy, The Ohio State University, Columbus, Ohio
| | - Milon Mondal
- Division of Pharmaceutics and Pharmacology, College of Pharmacy, The Ohio State University, Columbus, Ohio
| | - Xinyu Zhao
- Division of Pharmaceutics and Pharmacology, College of Pharmacy, The Ohio State University, Columbus, Ohio
| | - Jack C Yalowich
- Division of Pharmaceutics and Pharmacology, College of Pharmacy, The Ohio State University, Columbus, Ohio
| | - Terry S Elton
- Division of Pharmaceutics and Pharmacology, College of Pharmacy, The Ohio State University, Columbus, Ohio
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8
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Kurosaki T, Rambout X, Maquat LE. FMRP-mediated spatial regulation of physiologic NMD targets in neuronal cells. Genome Biol 2024; 25:31. [PMID: 38263082 PMCID: PMC10804635 DOI: 10.1186/s13059-023-03146-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2023] [Accepted: 12/14/2023] [Indexed: 01/25/2024] Open
Abstract
In non-polarized cells, nonsense-mediated mRNA decay (NMD) generally begins during the translation of newly synthesized mRNAs after the mRNAs are exported to the cytoplasm. Binding of the FMRP translational repressor to UPF1 on NMD targets mainly inhibits NMD. However, in polarized cells like neurons, FMRP additionally localizes mRNAs to cellular projections. Here, we review the literature and evaluate available transcriptomic data to conclude that, in neurons, the translation of physiologic NMD targets bound by FMRP is partially inhibited until the mRNAs localize to projections. There, FMRP displacement in response to signaling induces a burst in protein synthesis followed by rapid mRNA decay.
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Affiliation(s)
- Tatsuaki Kurosaki
- Department of Biochemistry and Biophysics, School of Medicine and Dentistry, University of Rochester, Rochester, NY, 14642, USA
- Center for RNA Biology, University of Rochester, Rochester, NY, 14642, USA
| | - Xavier Rambout
- Department of Biochemistry and Biophysics, School of Medicine and Dentistry, University of Rochester, Rochester, NY, 14642, USA
- Center for RNA Biology, University of Rochester, Rochester, NY, 14642, USA
| | - Lynne E Maquat
- Department of Biochemistry and Biophysics, School of Medicine and Dentistry, University of Rochester, Rochester, NY, 14642, USA.
- Center for RNA Biology, University of Rochester, Rochester, NY, 14642, USA.
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9
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Karousis ED, Schubert K, Ban N. Coronavirus takeover of host cell translation and intracellular antiviral response: a molecular perspective. EMBO J 2024; 43:151-167. [PMID: 38200146 PMCID: PMC10897431 DOI: 10.1038/s44318-023-00019-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2023] [Revised: 11/01/2023] [Accepted: 11/24/2023] [Indexed: 01/12/2024] Open
Abstract
Coronaviruses are a group of related RNA viruses that cause respiratory diseases in humans and animals. Understanding the mechanisms of translation regulation during coronaviral infections is critical for developing antiviral therapies and preventing viral spread. Translation of the viral single-stranded RNA genome in the host cell cytoplasm is an essential step in the life cycle of coronaviruses, which affects the cellular mRNA translation landscape in many ways. Here we discuss various viral strategies of translation control, including how members of the Betacoronavirus genus shut down host cell translation and suppress host innate immune functions, as well as the role of the viral non-structural protein 1 (Nsp1) in the process. We also outline the fate of viral RNA, considering stress response mechanisms triggered in infected cells, and describe how unique viral RNA features contribute to programmed ribosomal -1 frameshifting, RNA editing, and translation shutdown evasion.
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Affiliation(s)
- Evangelos D Karousis
- Multidisciplinary Center for Infectious Diseases, University of Bern, Bern, Switzerland
- Department of Chemistry and Biochemistry, University of Bern, Bern, Switzerland
| | - Katharina Schubert
- Department of Biology, Institute of Molecular Biology and Biophysics, ETH Zurich, Zurich, Switzerland
| | - Nenad Ban
- Department of Biology, Institute of Molecular Biology and Biophysics, ETH Zurich, Zurich, Switzerland.
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10
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Xu P, Tong W, Kuo CY, Chen HH, Wang RYL. The Upf1 protein restricts EV-A71 viral replication. Microbes Infect 2023; 25:105220. [PMID: 37734533 DOI: 10.1016/j.micinf.2023.105220] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2023] [Revised: 09/07/2023] [Accepted: 09/15/2023] [Indexed: 09/23/2023]
Abstract
Enterovirus A71 (EV-A71) is transmitted through the respiratory tract, gastrointestinal system, and fecal-oral routes. The main symptoms caused by EV-A71 are hand, foot, and mouth disease (HFMD) or vesicular sore throat. Upf1 (Up-frameshift protein 1) was reported to degrade mRNA containing early stop codons, known as nonsense-mediated decay (NMD). Upf1 is also involved in the NMD mechanism as a host factor detrimental to viral replication. In this study, we dissected the potential roles of Upf1 in the EV-A71-infected cells. Upf1 was virulently down-regulated in three different EV-A71-infected cells, RD, Hela, and 293T, implying that Upf1 is a host protein unfavorable for EV-A71 replication. Knockdown of Upf1 protein resulted in increased viral RNA expression and production of progeny virus, and conversely, overexpression of Upf1 protein resulted in decreased viral RNA expression and production of progeny virus. Importantly, we observed increased RNA levels of asparagine synthetase (ASNS), one of the indicator substrates for the NMD mechanism, which indirectly suggests that EV-A71 infection of cells suppresses NMD activity in the host. The results shown in this study are useful for subsequent analysis of the relationship between the NMD/Upf1 mechanism and other picornaviruses, which may lead to the development of anti-picornavirus drugs.
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Affiliation(s)
- Peng Xu
- Xiangyang No. 1 People's Hospital and Hubei University of Medicine; Hubei Province, China
| | - Wei Tong
- Department of Clinical Laboratory, Xiangyang No. 1 People's Hospital, Hubei University of Medicine, Xiangyang, China
| | - Chen-Yen Kuo
- Division of Pediatric Infectious Diseases, Department of Pediatrics, Chang Gung Memorial and Children's Hospital, Linkou 33305, Taiwan
| | - Han-Hsiang Chen
- Department of Biomedical Sciences, College of Medicine, Chang Gung University, Taoyuan 33302, Taiwan
| | - Robert Y L Wang
- Division of Pediatric Infectious Diseases, Department of Pediatrics, Chang Gung Memorial and Children's Hospital, Linkou 33305, Taiwan; Department of Biomedical Sciences, College of Medicine, Chang Gung University, Taoyuan 33302, Taiwan; Kidney Research Center and Department of Nephrology, Chang Gung Memorial Hospital, Linkou 33305, Taiwan.
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11
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Kalita AI, Marois E, Kozielska M, Weissing FJ, Jaouen E, Möckel MM, Rühle F, Butter F, Basilicata MF, Keller Valsecchi CI. The sex-specific factor SOA controls dosage compensation in Anopheles mosquitoes. Nature 2023; 623:175-182. [PMID: 37769784 PMCID: PMC10620080 DOI: 10.1038/s41586-023-06641-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2022] [Accepted: 09/13/2023] [Indexed: 10/03/2023]
Abstract
The Anopheles mosquito is one of thousands of species in which sex differences play a central part in their biology, as only females need a blood meal to produce eggs. Sex differentiation is regulated by sex chromosomes, but their presence creates a dosage imbalance between males (XY) and females (XX). Dosage compensation (DC) can re-equilibrate the expression of sex chromosomal genes. However, because DC mechanisms have only been fully characterized in a few model organisms, key questions about its evolutionary diversity and functional necessity remain unresolved1. Here we report the discovery of a previously uncharacterized gene (sex chromosome activation (SOA)) as a master regulator of DC in the malaria mosquito Anopheles gambiae. Sex-specific alternative splicing prevents functional SOA protein expression in females. The male isoform encodes a DNA-binding protein that binds the promoters of active X chromosomal genes. Expressing male SOA is sufficient to induce DC in female cells. Male mosquitoes lacking SOA or female mosquitoes ectopically expressing the male isoform exhibit X chromosome misregulation, which is compatible with viability but causes developmental delay. Thus, our molecular analyses of a DC master regulator in a non-model organism elucidates the evolutionary steps that lead to the establishment of a chromosome-specific fine-tuning mechanism.
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Affiliation(s)
| | - Eric Marois
- INSERM U1257, CNRS UPR9022, Université de Strasbourg, Strasbourg, France
| | - Magdalena Kozielska
- Groningen Institute for Evolutionary Life Sciences, University of Groningen, Groningen, Netherlands
| | - Franz J Weissing
- Groningen Institute for Evolutionary Life Sciences, University of Groningen, Groningen, Netherlands
| | - Etienne Jaouen
- INSERM U1257, CNRS UPR9022, Université de Strasbourg, Strasbourg, France
| | | | - Frank Rühle
- Institute of Molecular Biology (IMB), Mainz, Germany
| | - Falk Butter
- Institute of Molecular Biology (IMB), Mainz, Germany
- Institute of Molecular Virology and Cell Biology, Friedrich Loeffler Institute, Greifswald, Germany
| | - M Felicia Basilicata
- Institute of Molecular Biology (IMB), Mainz, Germany
- Institute of Human Genetics, University Medical Center of the Johannes Gutenberg University Mainz, Mainz, Germany
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12
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Meydan S, Guydosh NR. Is there a localized role for translational quality control? RNA (NEW YORK, N.Y.) 2023; 29:1623-1643. [PMID: 37582617 PMCID: PMC10578494 DOI: 10.1261/rna.079683.123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Accepted: 07/26/2023] [Indexed: 08/17/2023]
Abstract
It is known that mRNAs and the machinery that translates them are not uniformly distributed throughout the cytoplasm. As a result, the expression of some genes is localized to particular parts of the cell and this makes it possible to carry out important activities, such as growth and signaling, in three-dimensional space. However, the functions of localized gene expression are not fully understood, and the underlying mechanisms that enable localized expression have not been determined in many cases. One consideration that could help in addressing these challenges is the role of quality control (QC) mechanisms that monitor translating ribosomes. On a global level, QC pathways are critical for detecting aberrant translation events, such as a ribosome that stalls while translating, and responding by activating stress pathways and resolving problematic ribosomes and mRNAs at the molecular level. However, it is unclear how these pathways, even when uniformly active throughout the cell, affect local translation. Importantly, some QC pathways have themselves been reported to be enriched in the proximity of particular organelles, but the extent of such localized activity remains largely unknown. Here, we describe the major QC pathways and review studies that have begun to explore their roles in localized translation. Given the limited data in this area, we also pose broad questions about the possibilities and limitations for how QC pathways could facilitate localized gene expression in the cell with the goal of offering ideas for future experimentation.
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Affiliation(s)
- Sezen Meydan
- National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA
- National Institute of General Medical Sciences, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Nicholas R Guydosh
- National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA
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Gaspar LM, Gonçalves CI, Saraiva C, Cortez L, Amaral C, Nobre E, Lemos MC. Low frequency of AIP mutations in patients with young-onset sporadic pituitary macroadenomas. J Endocrinol Invest 2023; 46:2299-2307. [PMID: 37149543 PMCID: PMC10558361 DOI: 10.1007/s40618-023-02083-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/05/2023] [Accepted: 03/28/2023] [Indexed: 05/08/2023]
Abstract
PURPOSE Mutations in the aryl hydrocarbon receptor interacting protein (AIP) gene cause familial isolated pituitary adenomas (FIPA). AIP mutations have also been found in patients with apparently sporadic pituitary adenomas, particularly in young patients with large adenomas. The aim of this study was to determine the frequency of AIP germline mutations in patients with young-onset sporadic pituitary macroadenomas. METHODS The AIP gene was sequenced in 218 Portuguese patients with sporadic pituitary macroadenomas diagnosed before the age of 40 years. RESULTS Heterozygous rare sequence variants in AIP were identified in 18 (8.3%) patients. However, only four (1.8%) patients had pathogenic or likely pathogenic variants. These consisted of two already known mutations (p.Arg81* and p.Leu115Trpfs*41) and two novel mutations (p.Glu246*, p.Ser53Thrfs*36). All four patients had GH-secreting adenomas diagnosed between the ages of 14 and 25 years. The frequency of AIP pathogenic or likely pathogenic variants in patients under the age of 30 and 18 years was 3.4% and 5.0%, respectively. CONCLUSION The frequency of AIP mutations in this cohort was lower than in other studies. Previous reports may have overestimated the contribution of AIP mutations due to the inclusion of genetic variants of uncertain significance. The identification of novel AIP mutations expands the known spectrum of genetic causes of pituitary adenomas and may help understand the role of AIP mutations in the molecular mechanisms underlying pituitary tumorigenesis.
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Affiliation(s)
- L M Gaspar
- CICS-UBI, Health Sciences Research Centre, University of Beira Interior, 6200-506, Covilhã, Portugal
| | - C I Gonçalves
- CICS-UBI, Health Sciences Research Centre, University of Beira Interior, 6200-506, Covilhã, Portugal
| | - C Saraiva
- Serviço de Endocrinologia, Hospital de Egas Moniz, Centro Hospitalar Lisboa Ocidental, Lisbon, Portugal
| | - L Cortez
- Serviço de Endocrinologia, Hospital de Curry Cabral, Centro Hospitalar Universitário Lisboa Central, Lisbon, Portugal
| | - C Amaral
- Serviço de Endocrinologia, Hospital de Santo António, Centro Hospitalar Universitário do Porto, Porto, Portugal
| | - E Nobre
- Serviço de Endocrinologia, Diabetes e Metabolismo, Hospital de Santa Maria, Centro Hospitalar Universitário Lisboa Norte, Lisbon, Portugal
| | - M C Lemos
- CICS-UBI, Health Sciences Research Centre, University of Beira Interior, 6200-506, Covilhã, Portugal.
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Monaghan L, Longman D, Cáceres JF. Translation-coupled mRNA quality control mechanisms. EMBO J 2023; 42:e114378. [PMID: 37605642 PMCID: PMC10548175 DOI: 10.15252/embj.2023114378] [Citation(s) in RCA: 16] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2023] [Revised: 07/24/2023] [Accepted: 08/01/2023] [Indexed: 08/23/2023] Open
Abstract
mRNA surveillance pathways are essential for accurate gene expression and to maintain translation homeostasis, ensuring the production of fully functional proteins. Future insights into mRNA quality control pathways will enable us to understand how cellular mRNA levels are controlled, how defective or unwanted mRNAs can be eliminated, and how dysregulation of these can contribute to human disease. Here we review translation-coupled mRNA quality control mechanisms, including the non-stop and no-go mRNA decay pathways, describing their mechanisms, shared trans-acting factors, and differences. We also describe advances in our understanding of the nonsense-mediated mRNA decay (NMD) pathway, highlighting recent mechanistic findings, the discovery of novel factors, as well as the role of NMD in cellular physiology and its impact on human disease.
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Affiliation(s)
- Laura Monaghan
- MRC Human Genetics Unit, Institute of Genetics and CancerUniversity of EdinburghEdinburghUK
| | - Dasa Longman
- MRC Human Genetics Unit, Institute of Genetics and CancerUniversity of EdinburghEdinburghUK
| | - Javier F Cáceres
- MRC Human Genetics Unit, Institute of Genetics and CancerUniversity of EdinburghEdinburghUK
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15
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Petrić Howe M, Patani R. Nonsense-mediated mRNA decay in neuronal physiology and neurodegeneration. Trends Neurosci 2023; 46:879-892. [PMID: 37543480 DOI: 10.1016/j.tins.2023.07.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2023] [Revised: 06/19/2023] [Accepted: 07/09/2023] [Indexed: 08/07/2023]
Abstract
The processes of mRNA export from the nucleus and subsequent mRNA translation in the cytoplasm are of particular relevance in eukaryotic cells. In highly polarised cells such as neurons, finely-tuned molecular regulation of these processes serves to safeguard the spatiotemporal fidelity of gene expression. Nonsense-mediated mRNA decay (NMD) is a cytoplasmic translation-dependent quality control process that regulates gene expression in a wide range of scenarios in the nervous system, including neurodevelopment, learning, and memory formation. Moreover, NMD dysregulation has been implicated in a broad range of neurodevelopmental and neurodegenerative disorders. We discuss how NMD and related aspects of mRNA translation regulate key neuronal functions and, in particular, we focus on evidence implicating these processes in the molecular pathogenesis of neurodegeneration. Finally, we discuss the therapeutic potential and challenges of targeting mRNA translation and NMD across the spectrum of largely untreatable neurological diseases.
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Affiliation(s)
- Marija Petrić Howe
- The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK; Department of Neuromuscular Diseases, Queen Square Institute of Neurology, University College London (UCL), Queen Square, WC1N 3BG London, UK.
| | - Rickie Patani
- The Francis Crick Institute, 1 Midland Road, London NW1 1AT, UK; Department of Neuromuscular Diseases, Queen Square Institute of Neurology, University College London (UCL), Queen Square, WC1N 3BG London, UK.
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16
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Nasif S, Colombo M, Uldry AC, Schröder M, de Brot S, Mühlemann O. Inhibition of nonsense-mediated mRNA decay reduces the tumorigenicity of human fibrosarcoma cells. NAR Cancer 2023; 5:zcad048. [PMID: 37681034 PMCID: PMC10480688 DOI: 10.1093/narcan/zcad048] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2023] [Revised: 08/08/2023] [Accepted: 08/25/2023] [Indexed: 09/09/2023] Open
Abstract
Nonsense-mediated mRNA decay (NMD) is a eukaryotic RNA decay pathway with roles in cellular stress responses, differentiation, and viral defense. It functions in both quality control and post-transcriptional regulation of gene expression. NMD has also emerged as a modulator of cancer progression, although available evidence supports both a tumor suppressor and a pro-tumorigenic role, depending on the model. To further investigate the role of NMD in cancer, we knocked out the NMD factor SMG7 in the HT1080 human fibrosarcoma cell line, resulting in suppression of NMD function. We then compared the oncogenic properties of the parental cell line, the SMG7-knockout, and a rescue cell line in which we re-introduced both isoforms of SMG7. We also tested the effect of a drug inhibiting the NMD factor SMG1 to distinguish NMD-dependent effects from putative NMD-independent functions of SMG7. Using cell-based assays and a mouse xenograft tumor model, we showed that suppression of NMD function severely compromises the oncogenic phenotype. Molecular pathway analysis revealed that NMD suppression strongly reduces matrix metalloprotease 9 (MMP9) expression and that MMP9 re-expression partially rescues the oncogenic phenotype. Since MMP9 promotes cancer cell migration and invasion, metastasis and angiogenesis, its downregulation may contribute to the reduced tumorigenicity of NMD-suppressed cells. Collectively, our results highlight the potential value of NMD inhibition as a therapeutic approach.
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Affiliation(s)
- Sofia Nasif
- Department of Chemistry, Biochemistry and Pharmaceutical Sciences, University of Bern, Switzerland
| | - Martino Colombo
- Department of Chemistry, Biochemistry and Pharmaceutical Sciences, University of Bern, Switzerland
| | - Anne-Christine Uldry
- Proteomics & Mass Spectrometry Core Facility, Department for BioMedical Research, University of Bern, Switzerland
| | - Markus S Schröder
- NCCR RNA & Disease Bioinformatics Support,Department of Biology, ETH Zürich, Switzerland
| | - Simone de Brot
- COMPATH, Institute of Animal Pathology, University of Bern, Switzerland
| | - Oliver Mühlemann
- Department of Chemistry, Biochemistry and Pharmaceutical Sciences, University of Bern, Switzerland
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17
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McBeath E, Fujiwara K, Hofmann MC. Evidence-Based Guide to Using Artificial Introns for Tissue-Specific Knockout in Mice. Int J Mol Sci 2023; 24:10258. [PMID: 37373404 PMCID: PMC10299402 DOI: 10.3390/ijms241210258] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2023] [Revised: 06/09/2023] [Accepted: 06/10/2023] [Indexed: 06/29/2023] Open
Abstract
Up until recently, methods for generating floxed mice either conventionally or by CRISPR (Clustered Regularly Interspaced Short Palindromic Repeats)-Cas9 (CRISPR-associated protein 9) editing have been technically challenging, expensive and error-prone, or time-consuming. To circumvent these issues, several labs have started successfully using a small artificial intron to conditionally knockout (KO) a gene of interest in mice. However, many other labs are having difficulty getting the technique to work. The key problem appears to be either a failure in achieving correct splicing after the introduction of the artificial intron into the gene or, just as crucial, insufficient functional KO of the gene's protein after Cre-induced removal of the intron's branchpoint. Presented here is a guide on how to choose an appropriate exon and where to place the recombinase-regulated artificial intron (rAI) in that exon to prevent disrupting normal gene splicing while maximizing mRNA degradation after recombinase treatment. The reasoning behind each step in the guide is also discussed. Following these recommendations should increase the success rate of this easy, new, and alternative technique for producing tissue-specific KO mice.
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Affiliation(s)
- Elena McBeath
- Department of Endocrine Neoplasia & Hormonal Disorders, MD Anderson Cancer Center, Houston, TX 77030, USA;
| | - Keigi Fujiwara
- National Coalition of Independent Scholars, Brattleboro, VT 05301, USA;
| | - Marie-Claude Hofmann
- Department of Endocrine Neoplasia & Hormonal Disorders, MD Anderson Cancer Center, Houston, TX 77030, USA;
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Spelier S, van Doorn EPM, van der Ent CK, Beekman JM, Koppens MAJ. Readthrough compounds for nonsense mutations: bridging the translational gap. Trends Mol Med 2023; 29:297-314. [PMID: 36828712 DOI: 10.1016/j.molmed.2023.01.004] [Citation(s) in RCA: 15] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Revised: 12/28/2022] [Accepted: 01/19/2023] [Indexed: 02/24/2023]
Abstract
Approximately 10% of all pathological mutations are nonsense mutations that are responsible for several severe genetic diseases for which no treatment regimens are currently available. The most widespread strategy for treating nonsense mutations is by enhancing ribosomal readthrough of premature termination codons (PTCs) to restore the production of the full-length protein. In the past decade several compounds with readthrough potential have been identified. However, although preclinical results on these compounds are promising, clinical studies have not yielded positive outcomes. We review preclinical and clinical research related to readthrough compounds and characterize factors that contribute to the observed translational gap.
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Affiliation(s)
- Sacha Spelier
- Department of Pediatric Respiratory Medicine, Wilhelmina Children's Hospital, University Medical Center, Utrecht University, 3584, EA, Utrecht, The Netherlands; Regenerative Medicine Utrecht, University Medical Center, Utrecht University, 3584, CT, Utrecht, The Netherlands
| | - Eveline P M van Doorn
- Department of Pediatric Respiratory Medicine, Wilhelmina Children's Hospital, University Medical Center, Utrecht University, 3584, EA, Utrecht, The Netherlands
| | - Cornelis K van der Ent
- Department of Pediatric Respiratory Medicine, Wilhelmina Children's Hospital, University Medical Center, Utrecht University, 3584, EA, Utrecht, The Netherlands; Regenerative Medicine Utrecht, University Medical Center, Utrecht University, 3584, CT, Utrecht, The Netherlands
| | - Jeffrey M Beekman
- Department of Pediatric Respiratory Medicine, Wilhelmina Children's Hospital, University Medical Center, Utrecht University, 3584, EA, Utrecht, The Netherlands; Regenerative Medicine Utrecht, University Medical Center, Utrecht University, 3584, CT, Utrecht, The Netherlands; Center for Living Technologies, Eindhoven-Wageningen-Utrecht Alliance, Utrecht, The Netherlands
| | - Martijn A J Koppens
- Department of Pediatric Respiratory Medicine, Wilhelmina Children's Hospital, University Medical Center, Utrecht University, 3584, EA, Utrecht, The Netherlands; Regenerative Medicine Utrecht, University Medical Center, Utrecht University, 3584, CT, Utrecht, The Netherlands; Department of Metabolic Diseases, Wilhelmina Children's Hospital, University Medical Center, Utrecht University, 3584, EA, Utrecht, The Netherlands.
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Modulation of NBAS-Related Functions in the Early Response to SARS-CoV-2 Infection. Int J Mol Sci 2023; 24:ijms24032634. [PMID: 36768954 PMCID: PMC9916797 DOI: 10.3390/ijms24032634] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2022] [Revised: 01/20/2023] [Accepted: 01/23/2023] [Indexed: 01/31/2023] Open
Abstract
Upon infection, severe acute respiratory syndrome-coronavirus 2 (SARS-CoV-2) is predicted to interact with diverse cellular functions, such as the nonsense-mediated decay (NMD) pathway, as suggested by the identification of the core NMD factor upframeshift-1 (UPF1) in the SARS-CoV-2 interactome, and the retrograde transport from the Golgi to the endoplasmic reticulum (ER) through the endoplasmic reticulum-Golgi intermediate compartment (ERGIC), where coronavirus assembly occurs. Here, we investigated the expression and localization of the neuroblastoma-amplified sequence (NBAS) protein, a UPF1 partner for the NMD at the ER, participating also in retrograde transport, and of its functional partners, at early time points after SARS-CoV-2 infection of the human lung epithelial cell line Calu3. We found a significant decrease of DExH-Box Helicase 34 (DHX34), suppressor with morphogenetic effect on genitalia 5 (SMG5), and SMG7 expression at 6 h post-infection, followed by a significant increase of these genes and also UPF1 and UPF2 at 9 h post-infection. Conversely, NBAS and other genes coding for NMD factors were not modulated. Known NMD substrates related to cell stress (Growth Arrest Specific 5, GAS5; transducin beta-like 2, TBL2; and DNA damage-inducible transcript 3, DDIT3) were increased in infected cells, possibly as a result of alterations in the NMD pathway and of a direct effect of the infection. We also found that the expression of unconventional SNARE in the ER 1, USE1 (p31) and Zeste White 10 homolog, ZW10, partners of NBAS in the retrograde transport function, significantly increased over time in infected cells. Co-localization of NBAS and UPF1 proteins did not change within 24 h of infection nor did it differ in infected versus non-infected cells at 1 and 24 h after infection; similarly, the co-localization of NBAS and p31 proteins was not altered by infection in this short time frame. Finally, both NBAS and UPF1 were found to co-localize with SARS-CoV-2 S and N proteins. Overall, these data are preliminary evidence of an interaction between NBAS and NBAS-related functions and SARS-CoV-2 in infected cells, deserving further investigation.
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Bulleeraz V, Goy M, Basheer F, Liongue C, Ward AC. Leukemia-associated truncation of granulocyte colony-stimulating factor receptor impacts granulopoiesis throughout the life-course. Front Immunol 2023; 13:1095453. [PMID: 36703974 PMCID: PMC9871641 DOI: 10.3389/fimmu.2022.1095453] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2022] [Accepted: 12/20/2022] [Indexed: 01/11/2023] Open
Abstract
Introduction The granulocyte colony-stimulating factor receptor (G-CSFR), encoded by the CSF3R gene, is involved in the production and function of neutrophilic granulocytes. Somatic mutations in CSF3R leading to truncated G-CSFR forms are observed in acute myeloid leukemia (AML), particularly those subsequent to severe chronic neutropenia (SCN), as well as in a subset of patients with other leukemias. Methods This investigation introduced equivalent mutations into the zebrafish csf3r gene via genome editing and used a range of molecular and cellular techniques to understand the impact of these mutations on immune cells across the lifespan. Results Zebrafish harboring truncated G-CSFRs showed significantly enhanced neutrophil production throughout successive waves of embryonic hematopoiesis and a neutrophil maturation defect in adults, with the mutations acting in a partially dominant manner. Discussion This study has elucidated new insights into the impact of G-CSFR truncations throughout the life-course and created a bone fide zebrafish model for further investigation.
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Affiliation(s)
| | - Michelle Goy
- School of Medicine, Deakin University, Geelong, VIC, Australia
| | - Faiza Basheer
- School of Medicine, Deakin University, Geelong, VIC, Australia,Institute for Mental and Physical Health and Clinical Translation (IMPACT), Deakin University, Geelong, VIC, Australia
| | - Clifford Liongue
- School of Medicine, Deakin University, Geelong, VIC, Australia,Institute for Mental and Physical Health and Clinical Translation (IMPACT), Deakin University, Geelong, VIC, Australia
| | - Alister C. Ward
- School of Medicine, Deakin University, Geelong, VIC, Australia,Institute for Mental and Physical Health and Clinical Translation (IMPACT), Deakin University, Geelong, VIC, Australia,*Correspondence: Alister C. Ward,
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MAGED2 Is Required under Hypoxia for cAMP Signaling by Inhibiting MDM2-Dependent Endocytosis of G-Alpha-S. Cells 2022; 11:cells11162546. [PMID: 36010623 PMCID: PMC9406315 DOI: 10.3390/cells11162546] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2022] [Revised: 08/14/2022] [Accepted: 08/15/2022] [Indexed: 01/15/2023] Open
Abstract
Mutations in MAGED2 cause transient Bartter syndrome characterized by severe renal salt wasting in fetuses and infants, which leads to massive polyhydramnios causing preterm labor, extreme prematurity and perinatal death. Notably, this condition resolves spontaneously in parallel with developmental increase in renal oxygenation. MAGED2 interacts with G-alpha-S (Gαs). Given the role of Gαs in activating adenylyl cyclase at the plasma membrane and consequently generating cAMP to promote renal salt reabsorption via protein kinase A (PKA), we hypothesized that MAGED2 is required for this signaling pathway under hypoxic conditions such as in fetuses. Consistent with that, under both physical and chemical hypoxia, knockdown of MAGED2 in renal (HEK293) and cancer (HeLa) cell culture models caused internalization of Gαs, which was fully reversible upon reoxygenation. In contrast to Gαs, cell surface expression of the β2-adrenergic receptor, which is coupled to Gαs, was not affected by MAGED2 depletion, demonstrating specific regulation of Gαs by MAGED2. Importantly, the internalization of Gαs due to MAGED2 deficiency significantly reduced cAMP generation and PKA activity. Interestingly, the internalization of Gαs was blocked by preventing its endocytosis with dynasore. Given the role of E3 ubiquitin ligases, which can be regulated by MAGE-proteins, in regulating endocytosis, we assessed the potential role of MDM2-dependent ubiquitination in MAGED2 deficiency-induced internalization of Gαs under hypoxia. Remarkably, MDM2 depletion or its chemical inhibition fully abolished Gαs-endocytosis following MAGED2 knockdown. Moreover, endocytosis of Gαs was also blocked by mutation of ubiquitin acceptor sites in Gαs. Thus, we reveal that MAGED2 is essential for the cAMP/PKA pathway under hypoxia to specifically regulate Gαs endocytosis by blocking MDM2-dependent ubiquitination of Gαs. This may explain, at least in part, the transient nature of Bartter syndrome caused by MAGED2 mutations and opens new avenues for therapy in these patients.
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22
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Zhang X, Kebaara BW. Nonsense-mediated mRNA decay and metal ion homeostasis and detoxification in Saccharomyces cerevisiae. Biometals 2022; 35:1145-1156. [PMID: 36255607 PMCID: PMC9674712 DOI: 10.1007/s10534-022-00450-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Accepted: 09/21/2022] [Indexed: 12/14/2022]
Abstract
The highly conserved Nonsense-mediated mRNA decay (NMD) pathway is a translation dependent mRNA degradation pathway. Although NMD is best known for its role in degrading mRNAs with premature termination codons (PTCs) generated during transcription, splicing, or damage to the mRNAs, NMD is now also recognized as a pathway with additional important functions. Notably, NMD precisely regulates protein coding natural mRNAs, hence controlling gene expression within several physiologically significant pathways. Such pathways affected by NMD include nutritional bio-metal homeostasis and metal ion detoxification, as well as crosstalk between these pathways. Here, we focus on the relationships between NMD and various metal homeostasis and detoxification pathways. We review the described role that the NMD pathway plays in magnesium, zinc, iron, and copper homeostasis, as well as cadmium detoxification.
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Affiliation(s)
- Xinyi Zhang
- grid.252890.40000 0001 2111 2894Department of Biology, Baylor University, One Bear Place #97388, Waco, TX 76798 USA
| | - Bessie W. Kebaara
- grid.252890.40000 0001 2111 2894Department of Biology, Baylor University, One Bear Place #97388, Waco, TX 76798 USA
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