1
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Hou Y, Zhang C, Liu L, Yu Y, Shi L, Qin Y. WDR61 ablation triggers R-loop accumulation and suppresses breast cancer progression. FEBS J 2024; 291:3417-3431. [PMID: 38708718 DOI: 10.1111/febs.17145] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2023] [Revised: 02/09/2024] [Accepted: 04/12/2024] [Indexed: 05/07/2024]
Abstract
Although, superkiller complex protein 8 (SKI8), previously known as WDR61 has been identified and mapped in breast tumor, little is currently known about its function. This study aims to elucidate the role of WDR61 in breast tumor development and its potential as a therapeutic target. Here, we show that tamoxifen-induced knockout of Wdr61 reduces the risk of breast tumors, resulting in smaller tumor size and weight, and improved overall survival. Furthermore, we show that knockdown of WDR61 compromises the proliferation of breast tumor cells with reduced colony-forming capacity. Further investigations demonstrate that the protective effect of WDR61 loss on breast tumor development is due to genomic instability. Mechanistic studies reveal that WDR61 interacts with the R-loop, and loss of WDR61 leads to R-loops accumulation in breast tumor cells, causing DNA damage and subsequent inhibition of cell proliferation. In summary, this study highlights the critical dependence of breast tumors on WDR61, which suppresses R-loop and counteracts endogenous DNA damage in tumor cells.
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Affiliation(s)
- Yayan Hou
- State Key Laboratory of Experimental Hematology, Haihe Laboratory of Cell Ecosystem, Key Laboratory of Immune Microenvironment and Disease (Ministry of Education), The Province and Ministry Co-sponsored Collaborative Innovation Center for Medical Epigenetics, School of Basic Medical Sciences, Tianjin Medical University, China
| | - Chunyong Zhang
- State Key Laboratory of Experimental Hematology, Haihe Laboratory of Cell Ecosystem, Key Laboratory of Immune Microenvironment and Disease (Ministry of Education), The Province and Ministry Co-sponsored Collaborative Innovation Center for Medical Epigenetics, School of Basic Medical Sciences, Tianjin Medical University, China
| | - Ling Liu
- State Key Laboratory of Experimental Hematology, Haihe Laboratory of Cell Ecosystem, Key Laboratory of Immune Microenvironment and Disease (Ministry of Education), The Province and Ministry Co-sponsored Collaborative Innovation Center for Medical Epigenetics, School of Basic Medical Sciences, Tianjin Medical University, China
| | - Ying Yu
- State Key Laboratory of Experimental Hematology, Haihe Laboratory of Cell Ecosystem, Key Laboratory of Immune Microenvironment and Disease (Ministry of Education), The Province and Ministry Co-sponsored Collaborative Innovation Center for Medical Epigenetics, School of Basic Medical Sciences, Tianjin Medical University, China
| | - Lei Shi
- State Key Laboratory of Experimental Hematology, Haihe Laboratory of Cell Ecosystem, Key Laboratory of Immune Microenvironment and Disease (Ministry of Education), The Province and Ministry Co-sponsored Collaborative Innovation Center for Medical Epigenetics, School of Basic Medical Sciences, Tianjin Medical University, China
| | - Yan Qin
- State Key Laboratory of Experimental Hematology, Haihe Laboratory of Cell Ecosystem, Key Laboratory of Immune Microenvironment and Disease (Ministry of Education), The Province and Ministry Co-sponsored Collaborative Innovation Center for Medical Epigenetics, School of Basic Medical Sciences, Tianjin Medical University, China
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2
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Firdous Z, Kalra S, Chattopadhyay R, Bari VK. Current insight into the role of mRNA decay pathways in fungal pathogenesis. Microbiol Res 2024; 283:127671. [PMID: 38479232 DOI: 10.1016/j.micres.2024.127671] [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: 12/18/2023] [Revised: 02/19/2024] [Accepted: 02/29/2024] [Indexed: 04/17/2024]
Abstract
Pathogenic fungal species can cause superficial and mucosal infections, to potentially fatal systemic or invasive infections in humans. These infections are more common in immunocompromised or critically ill patients and have a significant morbidity and fatality rate. Fungal pathogens utilize several strategies to adapt the host environment resulting in efficient and comprehensive alterations in their cellular metabolism. Fungal virulence is regulated by several factors and post-transcriptional regulation mechanisms involving mRNA molecules are one of them. Post-transcriptional controls have emerged as critical regulatory mechanisms involved in the pathogenesis of fungal species. The untranslated upstream and downstream regions of the mRNA, as well as RNA-binding proteins, regulate morphogenesis and virulence by controlling mRNA degradation and stability. The limited number of available therapeutic drugs, the emergence of multidrug resistance, and high death rates associated with systemic fungal illnesses pose a serious risk to human health. Therefore, new antifungal treatments that specifically target mRNA pathway components can decrease fungal pathogenicity and when combined increase the effectiveness of currently available antifungal drugs. This review summarizes the mRNA degradation pathways and their role in fungal pathogenesis.
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Affiliation(s)
- Zulikha Firdous
- Department of Biochemistry, School of Basic Sciences, Central University of Punjab, VPO-Ghudda, Bathinda 151401, India
| | - Sapna Kalra
- Department of Biochemistry, School of Basic Sciences, Central University of Punjab, VPO-Ghudda, Bathinda 151401, India
| | - Rituja Chattopadhyay
- Department of Biochemistry, School of Basic Sciences, Central University of Punjab, VPO-Ghudda, Bathinda 151401, India
| | - Vinay Kumar Bari
- Department of Biochemistry, School of Basic Sciences, Central University of Punjab, VPO-Ghudda, Bathinda 151401, India.
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3
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Chaudhuri A, Paul S, Banerjea M, Das B. Polyadenylated versions of small non-coding RNAs in Saccharomyces cerevisiae are degraded by Rrp6p/Rrp47p independent of the core nuclear exosome. MICROBIAL CELL (GRAZ, AUSTRIA) 2024; 11:155-186. [PMID: 38783922 PMCID: PMC11115967 DOI: 10.15698/mic2024.05.823] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/13/2024] [Revised: 03/03/2024] [Accepted: 03/05/2024] [Indexed: 05/25/2024]
Abstract
In Saccharomyces cerevisiae, polyadenylated forms of mature (and not precursor) small non-coding RNAs (sncRNAs) those fail to undergo proper 3'-end maturation are subject to an active degradation by Rrp6p and Rrp47p, which does not require the involvement of core exosome and TRAMP components. In agreement with this finding, Rrp6p/Rrp47p is demonstrated to exist as an exosome-independent complex, which preferentially associates with mature polyadenylated forms of these sncRNAs. Consistent with this observation, a C-terminally truncated version of Rrp6p (Rrp6p-ΔC2) lacking physical association with the core nuclear exosome supports their decay just like its full-length version. Polyadenylation is catalyzed by both the canonical and non-canonical poly(A) polymerases, Pap1p and Trf4p. Analysis of the polyadenylation profiles in WT and rrp6-Δ strains revealed that the majority of the polyadenylation sites correspond to either one to three nucleotides upstream or downstream of their mature ends and their poly(A) tails ranges from 10-15 adenylate residues. Most interestingly, the accumulated polyadenylated snRNAs are functional in the rrp6-Δ strain and are assembled into spliceosomes. Thus, Rrp6p-Rrp47p defines a core nuclear exosome-independent novel RNA turnover system in baker's yeast targeting imperfectly processed polyadenylated sncRNAs that accumulate in the absence of Rrp6p.
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Affiliation(s)
- Anusha Chaudhuri
- Present Position: Zentrum fǜr Molekulare, Medizin, Institut fǜr Kardiovaskuläre Regeneration, Haus 25B, Goethe-Universität, Theodor-Stern-Kai 7, Universitätsklinikum, 60590 Frankfurt am Main, Germany
| | - Soumita Paul
- Department of Life Science and Biotechnology, Jadavpur University, 188 Raja S.C. Mullick Road, Kolkata – 700 032, West Bengal, India
| | - Mayukh Banerjea
- Department of Life Science and Biotechnology, Jadavpur University, 188 Raja S.C. Mullick Road, Kolkata – 700 032, West Bengal, India
| | - Biswadip Das
- Department of Life Science and Biotechnology, Jadavpur University, 188 Raja S.C. Mullick Road, Kolkata – 700 032, West Bengal, India
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4
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Saha U, Gaine R, Paira S, Das S, Das B. RRM1 and PAB domains of translation initiation factor eIF4G (Tif4631p) play a crucial role in the nuclear degradation of export-defective mRNAs in Saccharomyces cerevisiae. FEBS J 2024; 291:897-926. [PMID: 37994298 DOI: 10.1111/febs.17016] [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: 03/07/2023] [Revised: 10/02/2023] [Accepted: 11/21/2023] [Indexed: 11/24/2023]
Abstract
In Saccharomyces cerevisiae, the CBC-Tif4631p-dependent exosomal targeting (CTEXT) complex consisting of Cbc1/2p, Tif4631p and Upf3p promotes the exosomal degradation of aberrantly long 3'-extended, export-defective transcripts and a small group of normal (termed 'special') mRNAs. We carried out a systematic analysis of all previously characterized functional domains of the major CTEXT component Tif4631p by deleting each of them and interrogating their involvement in the nuclear surveillance of abnormally long 3'-extended and export-defective messages. Our analyses show that the N-terminal RNA recognition motif 1 (RRM1) and poly(A)-binding protein (PAB) domains of Tif4631p, spanning amino acid residues, 1-82 and 188-299 in its primary structure, respectively, play a crucial role in degrading these aberrant messages. Furthermore, the physical association of the nuclear exosome with the altered/variant CTEXT complex harboring any of the mutant Tif4631p proteins lacking either the RRM1 or PAB domain becomes abolished. This finding indicates that the association between CTEXT and the exosome is accomplished via interaction between these Tif4631p domains with the major exosome component, Rrp6p. Abolition of interaction between altered CTEXT (harboring any of the RRM1/PAB-deleted versions of Tif4631p) and the exosome further leads to the impaired recruitment of the RNA targets to the Rrp6p subunit of the exosome carried out by the RRM1/PAB domains of Tif4631p. When analyzing the Tif4631p-interacting proteins, we identified a DEAD-box RNA helicase (Dbp2p), as an interacting partner that turned out to be a previously unknown component of CTEXT. The present study provides a more complete description of the CTEXT complex and offers insight into the functional relationship of this complex with the nuclear exosome.
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Grants
- BT/PR27917/BRB/10/1673/2018 Department of Biotechnology, Ministry of Science and Technology, India
- BT/PR6078/BRB/10/1114/2012 Department of Biotechnology, Ministry of Science and Technology, India
- 38/1427/16/EMR-II Council of Scientific and Industrial Research, India
- 38/1280/11/EMR-II Council of Scientific and Industrial Research, India
- SR/SO/BB/0066/2012 Department of Science and Technology, Ministry of Science and Technology, India
- Department of Science & Technology and Biotechnology, Government of West Bengal
- SR/WOS-A/LS-1067/2014 Department of Science and Technology, India, WOS-A
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Affiliation(s)
- Upasana Saha
- Department of Life Science and Biotechnology, Jadavpur University, Kolkata, India
| | - Rajlaxmi Gaine
- Department of Life Science and Biotechnology, Jadavpur University, Kolkata, India
| | - Sunirmal Paira
- Department of Life Science and Biotechnology, Jadavpur University, Kolkata, India
| | - Satarupa Das
- Department of Life Science and Biotechnology, Jadavpur University, Kolkata, India
| | - Biswadip Das
- Department of Life Science and Biotechnology, Jadavpur University, Kolkata, India
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5
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de Amorim JL, Leung SW, Haji-Seyed-Javadi R, Hou Y, Yu DS, Ghalei H, Khoshnevis S, Yao B, Corbett AH. The putative RNA helicase DDX1 associates with the nuclear RNA exosome and modulates RNA/DNA hybrids (R-loops). J Biol Chem 2024; 300:105646. [PMID: 38219817 PMCID: PMC10875230 DOI: 10.1016/j.jbc.2024.105646] [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: 04/21/2023] [Revised: 12/19/2023] [Accepted: 12/23/2023] [Indexed: 01/16/2024] Open
Abstract
The RNA exosome is a ribonuclease complex that mediates both RNA processing and degradation. This complex is evolutionarily conserved, ubiquitously expressed, and required for fundamental cellular functions, including rRNA processing. The RNA exosome plays roles in regulating gene expression and protecting the genome, including modulating the accumulation of RNA-DNA hybrids (R-loops). The function of the RNA exosome is facilitated by cofactors, such as the RNA helicase MTR4, which binds/remodels RNAs. Recently, missense mutations in RNA exosome subunit genes have been linked to neurological diseases. One possibility to explain why missense mutations in genes encoding RNA exosome subunits lead to neurological diseases is that the complex may interact with cell- or tissue-specific cofactors that are impacted by these changes. To begin addressing this question, we performed immunoprecipitation of the RNA exosome subunit, EXOSC3, in a neuronal cell line (N2A), followed by proteomic analyses to identify novel interactors. We identified the putative RNA helicase, DDX1, as an interactor. DDX1 plays roles in double-strand break repair, rRNA processing, and R-loop modulation. To explore the functional connections between EXOSC3 and DDX1, we examined the interaction following double-strand breaks and analyzed changes in R-loops in N2A cells depleted for EXOSC3 or DDX1 by DNA/RNA immunoprecipitation followed by sequencing. We find that EXOSC3 interaction with DDX1 is decreased in the presence of DNA damage and that loss of EXOSC3 or DDX1 alters R-loops. These results suggest EXOSC3 and DDX1 interact during events of cellular homeostasis and potentially suppress unscrupulous expression of genes promoting neuronal projection.
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Affiliation(s)
- Julia L de Amorim
- Department of Biology, Emory College of Arts and Sciences, Atlanta, Georgia, USA; Graduate Program in Biochemistry, Cell, and Development Biology, Emory University, Atlanta, Georgia, USA
| | - Sara W Leung
- Department of Biology, Emory College of Arts and Sciences, Atlanta, Georgia, USA
| | - Ramona Haji-Seyed-Javadi
- Department of Radiation Oncology, Winship Cancer Institute, Emory University School of Medicine, Atlanta, Georgia, USA; Graduate Program in Genetics and Molecular Biology Graduate Program, Emory University, Atlanta, Georgia, USA
| | - Yingzi Hou
- Department of Human Genetics, Emory University School of Medicine, Atlanta, Georgia, USA
| | - David S Yu
- Department of Radiation Oncology, Winship Cancer Institute, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Homa Ghalei
- Department of Biochemistry, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Sohail Khoshnevis
- Department of Biochemistry, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Bing Yao
- Department of Human Genetics, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Anita H Corbett
- Department of Biology, Emory College of Arts and Sciences, Atlanta, Georgia, USA.
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6
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Tomecki R, Drazkowska K, Kobylecki K, Tudek A. SKI complex: A multifaceted cytoplasmic RNA exosome cofactor in mRNA metabolism with links to disease, developmental processes, and antiviral responses. WILEY INTERDISCIPLINARY REVIEWS. RNA 2023; 14:e1795. [PMID: 37384835 DOI: 10.1002/wrna.1795] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2023] [Revised: 04/26/2023] [Accepted: 05/01/2023] [Indexed: 07/01/2023]
Abstract
RNA stability and quality control are integral parts of gene expression regulation. A key factor shaping eukaryotic transcriptomes, mainly via 3'-5' exoribonucleolytic trimming or degradation of diverse transcripts in nuclear and cytoplasmic compartments, is the RNA exosome. Precise exosome targeting to various RNA molecules requires strict collaboration with specialized auxiliary factors, which facilitate interactions with its substrates. The predominant class of cytoplasmic RNA targeted by the exosome are protein-coding transcripts, which are carefully scrutinized for errors during translation. Normal, functional mRNAs are turned over following protein synthesis by the exosome or by Xrn1 5'-3'-exonuclease, acting in concert with Dcp1/2 decapping complex. In turn, aberrant transcripts are eliminated by dedicated surveillance pathways, triggered whenever ribosome translocation is impaired. Cytoplasmic 3'-5' mRNA decay and surveillance are dependent on the tight cooperation between the exosome and its evolutionary conserved co-factor-the SKI (superkiller) complex (SKIc). Here, we summarize recent findings from structural, biochemical, and functional studies of SKIc roles in controlling cytoplasmic RNA metabolism, including links to various cellular processes. Mechanism of SKIc action is illuminated by presentation of its spatial structure and details of its interactions with exosome and ribosome. Furthermore, contribution of SKIc and exosome to various mRNA decay pathways, usually converging on recycling of ribosomal subunits, is delineated. A crucial physiological role of SKIc is emphasized by describing association between its dysfunction and devastating human disease-a trichohepatoenteric syndrome (THES). Eventually, we discuss SKIc functions in the regulation of antiviral defense systems, cell signaling and developmental transitions, emerging from interdisciplinary investigations. This article is categorized under: RNA Turnover and Surveillance > Turnover/Surveillance Mechanisms RNA Turnover and Surveillance > Regulation of RNA Stability RNA Interactions with Proteins and Other Molecules > RNA-Protein Complexes.
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Affiliation(s)
- Rafal Tomecki
- Laboratory of RNA Processing and Decay, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland
- Institute of Genetics and Biotechnology, Faculty of Biology, University of Warsaw, Warsaw, Poland
| | - Karolina Drazkowska
- Laboratory of Epitranscriptomics, Department of Environmental Microbiology and Biotechnology, Institute of Microbiology, Faculty of Biology, Biological and Chemical Research Centre, University of Warsaw, Warsaw, Poland
| | - Kamil Kobylecki
- Laboratory of RNA Processing and Decay, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland
| | - Agnieszka Tudek
- Laboratory of RNA Processing and Decay, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland
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7
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Lipińska-Zubrycka L, Grochowski M, Bähler J, Małecki M. Pervasive mRNA uridylation in fission yeast is catalysed by both Cid1 and Cid16 terminal uridyltransferases. PLoS One 2023; 18:e0285576. [PMID: 37220133 DOI: 10.1371/journal.pone.0285576] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Accepted: 04/25/2023] [Indexed: 05/25/2023] Open
Abstract
Messenger RNA uridylation is pervasive and conserved among eukaryotes, but the consequences of this modification for mRNA fate are still under debate. Utilising a simple model organism to study uridylation may facilitate efforts to understand the cellular function of this process. Here we demonstrate that uridylation can be detected using simple bioinformatics approach. We utilise it to unravel widespread transcript uridylation in fission yeast and demonstrate the contribution of both Cid1 and Cid16, the only two annotated terminal uridyltransferases (TUT-ases) in this yeast. To detect uridylation in transcriptome data, we used a RNA-sequencing (RNA-seq) library preparation protocol involving initial linker ligation to fragmented RNA-an approach borrowed from small RNA sequencing that was commonly used in older RNA-seq protocols. We next explored the data to detect uridylation marks. Our analysis show that uridylation in yeast is pervasive, similarly to the one in multicellular organisms. Importantly, our results confirm the role of the cytoplasmic uridyltransferase Cid1 as the primary uridylation catalyst. However, we also observed an auxiliary role of the second uridyltransferase, Cid16. Thus both fission yeast uridyltransferases are involved in mRNA uridylation. Intriguingly, we found no physiological phenotype of the single and double deletion mutants of cid1 and cid16 and only minimal impact of uridylation on steady-state mRNA levels. Our work establishes fission yeast as a potent model to study uridylation in a simple eukaryote, and we demonstrate that it is possible to detect uridylation marks in RNA-seq data without the need for specific methodologies.
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Affiliation(s)
- Lidia Lipińska-Zubrycka
- Institute of Genetics and Biotechnology, Faculty of Biology, University of Warsaw, Warsaw, Poland
| | - Maciej Grochowski
- Institute of Genetics and Biotechnology, Faculty of Biology, University of Warsaw, Warsaw, Poland
| | - Jürg Bähler
- Institute of Healthy Ageing and Research Department of Genetics, Evolution & Environment, University College London, London, United Kingdom
| | - Michał Małecki
- Institute of Genetics and Biotechnology, Faculty of Biology, University of Warsaw, Warsaw, Poland
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8
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de Amorim JL, Leung SW, Haji-Seyed-Javadi R, Hou Y, Yu DS, Ghalei H, Khoshnevis S, Yao B, Corbett AH. The RNA helicase DDX1 associates with the nuclear RNA exosome and modulates R-loops. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.04.17.537228. [PMID: 37131662 PMCID: PMC10153151 DOI: 10.1101/2023.04.17.537228] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
The RNA exosome is a ribonuclease complex that mediates both RNA processing and degradation. This complex is evolutionarily conserved, ubiquitously expressed, and required for fundamental cellular functions, including rRNA processing. The RNA exosome plays roles in regulating gene expression and protecting the genome, including modulating the accumulation of RNA-DNA hybrids (R-loops). The function of the RNA exosome is facilitated by cofactors, such as the RNA helicase MTR4, which binds/remodels RNAs. Recently, missense mutations in RNA exosome subunit genes have been linked to neurological diseases. One possibility to explain why missense mutations in genes encoding RNA exosome subunits lead to neurological diseases is that the complex may interact with cell- or tissue-specific cofactors that are impacted by these changes. To begin addressing this question, we performed immunoprecipitation of the RNA exosome subunit, EXOSC3, in a neuronal cell line (N2A) followed by proteomic analyses to identify novel interactors. We identified the putative RNA helicase, DDX1, as an interactor. DDX1 plays roles in double-strand break repair, rRNA processing, and R-loop modulation. To explore the functional connections between EXOSC3 and DDX1, we examined the interaction following double-strand breaks, and analyzed changes in R-loops in N2A cells depleted for EXOSC3 or DDX1 by DNA/RNA immunoprecipitation followed by sequencing (DRIP-Seq). We find that EXOSC3 interaction with DDX1 is decreased in the presence of DNA damage and that loss of EXOSC3 or DDX1 alters R-loops. These results suggest EXOSC3 and DDX1 interact during events of cellular homeostasis and potentially suppress unscrupulous expression of genes promoting neuronal projection.
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9
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Orlando LJ, Yim MK, Hallmark T, Cotner M, Johnson SJ, van Hoof A. A yeast model for trichohepatoenteric syndrome suggests strong loss of Ski2 function in most causative mutations. MICROPUBLICATION BIOLOGY 2022; 2022:10.17912/micropub.biology.000575. [PMID: 35607352 PMCID: PMC9123431 DOI: 10.17912/micropub.biology.000575] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/29/2022] [Revised: 05/13/2022] [Accepted: 05/19/2022] [Indexed: 12/01/2022]
Abstract
The intestinal and immune disorder trichohepatoenteric syndrome (THES) is characterized by mutations in human Ski2 and Ski3, also known as SKIV2L and TTC37, respectively. The mechanism by which these mutations leads to the immunodeficiency, chronic diarrhea, failure to thrive and liver disease associated with THES is unknown. To what degree THES patient mutations in Ski2 affect Ski2 function and how the differences in Ski2 function could lead to varying patient outcomes has not been studied. Here, we assayed function of THES ski2 mutants in the yeast homolog. Our results show that most THES patient mutations cause severe dysfunction in Ski2. This provides the first functional analysis of these mutations and suggests that the yeast assay may be helpful in distinguishing between pathological and benign variants.
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Affiliation(s)
- Luisa J Orlando
- Department of Microbiology and Molecular Genetics, The University of Texas Health Science Center at Houston and The University of Texas MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences, Houston
| | - Matthew K Yim
- Department of Chemistry and Biochemistry, Utah State University, Logan, Utah
| | - Thomson Hallmark
- Department of Chemistry and Biochemistry, Utah State University, Logan, Utah
| | - Michael Cotner
- Department of Chemistry and Biochemistry, Utah State University, Logan, Utah
| | - Sean J Johnson
- Department of Chemistry and Biochemistry, Utah State University, Logan, Utah
| | - Ambro van Hoof
- Department of Microbiology and Molecular Genetics, The University of Texas Health Science Center at Houston and The University of Texas MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences, Houston
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10
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Mishra R, Bansal A, Mishra A. LISTERIN E3 Ubiquitin Ligase and Ribosome-Associated Quality Control (RQC) Mechanism. Mol Neurobiol 2021; 58:6593-6609. [PMID: 34590243 DOI: 10.1007/s12035-021-02564-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Accepted: 09/12/2021] [Indexed: 01/09/2023]
Abstract
According to cellular demands, ribosomes synthesize and maintain the desired pool of proteins inside the cell. However, sometimes due to defects in ribosomal machinery and faulty mRNAs, these nascent polypeptides are constantly under threat to become non-functional. In such conditions, cells acquire the help of ribosome-associated quality control mechanisms (RQC) to eliminate such aberrant nascent proteins. The primary regulator of RQC is RING domain containing LISTERIN E3 ubiquitin ligase, which is associated with ribosomes and alleviates non-stop proteins-associated stress in cells. Mouse RING finger protein E3 ubiquitin ligase LISTERIN is crucial for embryonic development, and a loss in its function causes neurodegeneration. LISTERIN is overexpressed in the mouse brain and spinal cord regions, and its perturbed functions generate neurological and motor deficits, but the mechanism of the same is unclear. Overall, LISTERIN is crucial for brain health and brain development. The present article systematically describes the detailed nature, molecular functions, and cellular physiological characterization of LISTERIN E3 ubiquitin ligase. Improve comprehension of LISTERIN's neurological roles may uncover pathways linked with neurodegeneration, which in turn might elucidate a promising novel therapeutic intervention against human neurodegenerative diseases.
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Affiliation(s)
- Ribhav Mishra
- Cellular and Molecular Neurobiology Unit, Indian Institute of Technology Jodhpur, Karwar, Rajasthan, 342037, India
| | - Anurag Bansal
- Center for Converging Technologies, Jaipur, University of Rajasthan, Jaipur, 302001, India
| | - Amit Mishra
- Cellular and Molecular Neurobiology Unit, Indian Institute of Technology Jodhpur, Karwar, Rajasthan, 342037, India.
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11
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Effects of aging on protein expression in mice brain microvessels: ROS scavengers, mRNA/protein stability, glycolytic enzymes, mitochondrial complexes, and basement membrane components. GeroScience 2021; 44:371-388. [PMID: 34708300 PMCID: PMC8811117 DOI: 10.1007/s11357-021-00468-1] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Accepted: 09/23/2021] [Indexed: 12/25/2022] Open
Abstract
Differentially expressed (DE) proteins in the cortical microvessels (MVs) of young, middle-aged, and old male and female mice were evaluated using discovery-based proteomics analysis (> 4,200 quantified proteins/group). Most DE proteins (> 90%) showed no significant differences between the sexes; however, some significant DE proteins showing sexual differences in MVs decreased from young (8.3%), to middle-aged (3.7%), to old (0.5%) mice. Therefore, we combined male and female data for age-dependent comparisons but noted sex differences for examination. Key proteins involved in the oxidative stress response, mRNA or protein stability, basement membrane (BM) composition, aerobic glycolysis, and mitochondrial function were significantly altered with aging. Relative abundance of superoxide dismutase-1/-2, catalase and thioredoxin were reduced with aging. Proteins participating in either mRNA degradation or pre-mRNA splicing were significantly increased in old mice MVs, whereas protein stabilizing proteins decreased. Glycolytic proteins were not affected in middle age, but the relative abundance of these proteins decreased in MVs of old mice. Although most of the 41 examined proteins composing mitochondrial complexes I–V were reduced in old mice, six of these proteins showed a significant reduction in middle-aged mice, but the relative abundance increased in fourteen proteins. Nidogen, collagen, and laminin family members as well as perlecan showed differing patterns during aging, indicating BM reorganization starting in middle age. We suggest that increased oxidative stress during aging leads to adverse protein profile changes of brain cortical MVs that affect mRNA/protein stability, BM integrity, and ATP synthesis capacity.
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12
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Cabrera-Quio LE, Schleiffer A, Mechtler K, Pauli A. Zebrafish Ski7 tunes RNA levels during the oocyte-to-embryo transition. PLoS Genet 2021; 17:e1009390. [PMID: 33600438 PMCID: PMC7924785 DOI: 10.1371/journal.pgen.1009390] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Revised: 03/02/2021] [Accepted: 02/01/2021] [Indexed: 12/13/2022] Open
Abstract
Post-transcriptional regulation of gene expression is crucial during the oocyte-to-embryo transition, a highly dynamic process characterized by the absence of nuclear transcription. Thus, changes to the RNA content are solely dependent on RNA degradation. Although several mechanisms that promote RNA decay during embryogenesis have been identified, it remains unclear which machineries contribute to remodeling the maternal transcriptome. Here, we focused on the degradation factor Ski7 in zebrafish. Homozygous ski7 mutant fish had higher proportions of both poor quality eggs and eggs that were unable to develop beyond the one-cell stage. Consistent with the idea that Ski7 participates in remodeling the maternal RNA content, transcriptome profiling identified hundreds of misregulated mRNAs in the absence of Ski7. Furthermore, upregulated genes were generally lowly expressed in wild type, suggesting that Ski7 maintains low transcript levels for this subset of genes. Finally, GO enrichment and proteomic analyses of misregulated factors implicated Ski7 in the regulation of redox processes. This was confirmed experimentally by an increased resistance of ski7 mutant embryos to reductive stress. Our results provide first insights into the physiological role of vertebrate Ski7 as a post-transcriptional regulator during the oocyte-to-embryo transition.
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Affiliation(s)
| | - Alexander Schleiffer
- Research Institute of Molecular Pathology (IMP), Vienna Biocenter (VBC), Vienna, Austria
| | - Karl Mechtler
- Institute of Molecular Biotechnology, IMBA, Campus Vienna-Biocenter (VBC), Vienna, Austria
| | - Andrea Pauli
- Research Institute of Molecular Pathology (IMP), Vienna Biocenter (VBC), Vienna, Austria
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13
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Kim M, van Hoof A. Suppressors of mRNA Decapping Defects Restore Growth Without Major Effects on mRNA Decay Rates or Abundance. Genetics 2020; 216:1051-1069. [PMID: 32998951 PMCID: PMC7768250 DOI: 10.1534/genetics.120.303641] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Accepted: 09/28/2020] [Indexed: 01/09/2023] Open
Abstract
Faithful degradation of mRNAs is a critical step in gene expression, and eukaryotes share a major conserved mRNA decay pathway. In this major pathway, the two rate-determining steps in mRNA degradation are the initial gradual removal of the poly(A) tail, followed by removal of the cap structure. Removal of the cap structure is carried out by the decapping enzyme, containing the Dcp2 catalytic subunit. Although the mechanism and regulation of mRNA decay is well understood, the consequences of defects in mRNA degradation are less clear. Dcp2 has been reported as either essential or nonessential. Here, we clarify that Dcp2 is not absolutely required for spore germination and extremely slow growth, but in practical terms it is impossible to continuously culture dcp2∆ under laboratory conditions without suppressors arising. We show that null mutations in at least three different genes are each sufficient to restore growth to a dcp2∆, of which kap123∆ and tl(gag)g∆ appear the most specific. We show that kap123∆ and tl(gag)g∆ suppress dcp2 by mechanisms that are different from each other and from previously isolated dcp2 suppressors. The suppression mechanism for tL(GAG)G is determined by the unique GAG anticodon of this tRNA, and thus likely by translation of some CUC or CUU codons. Unlike previously reported suppressors of decapping defects, these suppressors do not detectably restore decapping or mRNA decay to normal rates, but instead allow survival while only modestly affecting RNA homeostasis. These results provide important new insight into the importance of decapping, resolve previously conflicting publications about the essentiality of DCP2, provide the first phenotype for a tl(gag)g mutant, and show that multiple distinct mechanisms can bypass Dcp2 requirement.
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Affiliation(s)
- Minseon Kim
- Microbiology and Molecular Genetics Department, University of Texas Health Science Center at Houston, Houston, Texas 77030
| | - Ambro van Hoof
- Microbiology and Molecular Genetics Department, University of Texas Health Science Center at Houston, Houston, Texas 77030
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14
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Hurtig JE, Kim M, Orlando-Coronel LJ, Ewan J, Foreman M, Notice LA, Steiger MA, van Hoof A. Origin, conservation, and loss of alternative splicing events that diversify the proteome in Saccharomycotina budding yeasts. RNA (NEW YORK, N.Y.) 2020; 26:1464-1480. [PMID: 32631843 PMCID: PMC7491326 DOI: 10.1261/rna.075655.120] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Accepted: 07/02/2020] [Indexed: 05/03/2023]
Abstract
Many eukaryotes use RNA processing, including alternative splicing, to express multiple gene products from the same gene. The budding yeast Saccharomyces cerevisiae has been successfully used to study the mechanism of splicing and the splicing machinery, but alternative splicing in yeast is relatively rare and has not been extensively studied. Alternative splicing of SKI7/HBS1 is widely conserved, but yeast and a few other eukaryotes have replaced this one alternatively spliced gene with a pair of duplicated, unspliced genes as part of a whole genome doubling (WGD). We show that other examples of alternative splicing known to have functional consequences are widely conserved within Saccharomycotina. A common mechanism by which alternative splicing has disappeared is by replacement of an alternatively spliced gene with duplicate unspliced genes. This loss of alternative splicing does not always take place soon after duplication, but can take place after sufficient time has elapsed for speciation. Saccharomycetaceae that diverged before WGD use alternative splicing more frequently than S. cerevisiae, suggesting that WGD is a major reason for infrequent alternative splicing in yeast. We anticipate that WGDs in other lineages may have had the same effect. Having observed that two functionally distinct splice-isoforms are often replaced by duplicated genes allowed us to reverse the reasoning. We thereby identify several splice isoforms that are likely to produce two functionally distinct proteins because we find them replaced by duplicated genes in related species. We also identify some alternative splicing events that are not conserved in closely related species and unlikely to produce functionally distinct proteins.
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Affiliation(s)
- Jennifer E Hurtig
- Microbiology and Molecular Genetics Department, University of Texas Health Science Center-Houston, Houston, Texas 77030, USA
| | - Minseon Kim
- Microbiology and Molecular Genetics Department, University of Texas Health Science Center-Houston, Houston, Texas 77030, USA
| | - Luisa J Orlando-Coronel
- Microbiology and Molecular Genetics Department, University of Texas Health Science Center-Houston, Houston, Texas 77030, USA
| | - Jellisa Ewan
- Microbiology and Molecular Genetics Department, University of Texas Health Science Center-Houston, Houston, Texas 77030, USA
| | - Michelle Foreman
- Microbiology and Molecular Genetics Department, University of Texas Health Science Center-Houston, Houston, Texas 77030, USA
| | - Lee-Ann Notice
- Microbiology and Molecular Genetics Department, University of Texas Health Science Center-Houston, Houston, Texas 77030, USA
| | - Michelle A Steiger
- Department of Chemistry and Biochemistry, University of St. Thomas, Houston, Texas 77006, USA
| | - Ambro van Hoof
- Microbiology and Molecular Genetics Department, University of Texas Health Science Center-Houston, Houston, Texas 77030, USA
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15
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Phung DK, Etienne C, Batista M, Langendijk-Genevaux P, Moalic Y, Laurent S, Liuu S, Morales V, Jebbar M, Fichant G, Bouvier M, Flament D, Clouet-d’Orval B. RNA processing machineries in Archaea: the 5'-3' exoribonuclease aRNase J of the β-CASP family is engaged specifically with the helicase ASH-Ski2 and the 3'-5' exoribonucleolytic RNA exosome machinery. Nucleic Acids Res 2020; 48:3832-3847. [PMID: 32030412 PMCID: PMC7144898 DOI: 10.1093/nar/gkaa052] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2019] [Revised: 01/14/2020] [Accepted: 01/23/2020] [Indexed: 01/22/2023] Open
Abstract
A network of RNA helicases, endoribonucleases and exoribonucleases regulates the quantity and quality of cellular RNAs. To date, mechanistic studies focussed on bacterial and eukaryal systems due to the challenge of identifying the main drivers of RNA decay and processing in Archaea. Here, our data support that aRNase J, a 5'-3' exoribonuclease of the β-CASP family conserved in Euryarchaeota, engages specifically with a Ski2-like helicase and the RNA exosome to potentially exert control over RNA surveillance, at the vicinity of the ribosome. Proteomic landscapes and direct protein-protein interaction analyses, strengthened by comprehensive phylogenomic studies demonstrated that aRNase J interplay with ASH-Ski2 and a cap exosome subunit. Finally, Thermococcus barophilus whole-cell extract fractionation experiments provide evidences that an aRNase J/ASH-Ski2 complex might exist in vivo and hint at an association of aRNase J with the ribosome that is emphasised in absence of ASH-Ski2. Whilst aRNase J homologues are found among bacteria, the RNA exosome and the Ski2-like RNA helicase have eukaryotic homologues, underlining the mosaic aspect of archaeal RNA machines. Altogether, these results suggest a fundamental role of β-CASP RNase/helicase complex in archaeal RNA metabolism.
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Affiliation(s)
- Duy Khanh Phung
- Laboratoire de Microbiologie et de Génétique Moléculaires, UMR5100, Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, Université Paul Sabatier, F-31062 Toulouse, France
| | - Clarisse Etienne
- Laboratoire de Microbiologie et de Génétique Moléculaires, UMR5100, Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, Université Paul Sabatier, F-31062 Toulouse, France
| | - Manon Batista
- Laboratoire de Microbiologie et de Génétique Moléculaires, UMR5100, Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, Université Paul Sabatier, F-31062 Toulouse, France
| | - Petra Langendijk-Genevaux
- Laboratoire de Microbiologie et de Génétique Moléculaires, UMR5100, Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, Université Paul Sabatier, F-31062 Toulouse, France
| | - Yann Moalic
- Ifremer, Univ Brest, CNRS, Laboratoire de Microbiologie des Environnements Extrêmes, F-29280 Plouzané, France
| | - Sébastien Laurent
- Ifremer, Univ Brest, CNRS, Laboratoire de Microbiologie des Environnements Extrêmes, F-29280 Plouzané, France
| | - Sophie Liuu
- Micalis Institute, PAPPSO, INRA, AgroParisTech, Université Paris-Saclay, 78350, Jouy-en-Josas, France
| | - Violette Morales
- Laboratoire de Microbiologie et de Génétique Moléculaires, UMR5100, Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, Université Paul Sabatier, F-31062 Toulouse, France
| | - Mohamed Jebbar
- Ifremer, Univ Brest, CNRS, Laboratoire de Microbiologie des Environnements Extrêmes, F-29280 Plouzané, France
| | - Gwennaele Fichant
- Laboratoire de Microbiologie et de Génétique Moléculaires, UMR5100, Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, Université Paul Sabatier, F-31062 Toulouse, France
| | - Marie Bouvier
- Laboratoire de Microbiologie et de Génétique Moléculaires, UMR5100, Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, Université Paul Sabatier, F-31062 Toulouse, France
| | - Didier Flament
- Ifremer, Univ Brest, CNRS, Laboratoire de Microbiologie des Environnements Extrêmes, F-29280 Plouzané, France
| | - Béatrice Clouet-d’Orval
- Laboratoire de Microbiologie et de Génétique Moléculaires, UMR5100, Centre de Biologie Intégrative (CBI), Université de Toulouse, CNRS, Université Paul Sabatier, F-31062 Toulouse, France
- To whom correspondence should be addressed. Tel: +33 561 335 875; Fax: +33 561 335 886;
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16
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Tuck AC, Rankova A, Arpat AB, Liechti LA, Hess D, Iesmantavicius V, Castelo-Szekely V, Gatfield D, Bühler M. Mammalian RNA Decay Pathways Are Highly Specialized and Widely Linked to Translation. Mol Cell 2020; 77:1222-1236.e13. [PMID: 32048998 PMCID: PMC7083229 DOI: 10.1016/j.molcel.2020.01.007] [Citation(s) in RCA: 55] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2019] [Revised: 11/11/2019] [Accepted: 01/07/2020] [Indexed: 12/24/2022]
Abstract
RNA decay is crucial for mRNA turnover and surveillance and misregulated in many diseases. This complex system is challenging to study, particularly in mammals, where it remains unclear whether decay pathways perform specialized versus redundant roles. Cytoplasmic pathways and links to translation are particularly enigmatic. By directly profiling decay factor targets and normal versus aberrant translation in mouse embryonic stem cells (mESCs), we uncovered extensive decay pathway specialization and crosstalk with translation. XRN1 (5'-3') mediates cytoplasmic bulk mRNA turnover whereas SKIV2L (3'-5') is universally recruited by ribosomes, tackling aberrant translation and sometimes modulating mRNA abundance. Further exploring translation surveillance revealed AVEN and FOCAD as SKIV2L interactors. AVEN prevents ribosome stalls at structured regions, which otherwise require SKIV2L for clearance. This pathway is crucial for histone translation, upstream open reading frame (uORF) regulation, and counteracting ribosome arrest on small ORFs. In summary, we uncovered key targets, components, and functions of mammalian RNA decay pathways and extensive coupling to translation.
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Affiliation(s)
- Alex Charles Tuck
- Friedrich Miescher Institute for Biomedical Research, Maulbeerstrasse 66, 4058 Basel, Switzerland
| | - Aneliya Rankova
- Friedrich Miescher Institute for Biomedical Research, Maulbeerstrasse 66, 4058 Basel, Switzerland
| | - Alaaddin Bulak Arpat
- Center for Integrative Genomics, University of Lausanne, 1015 Lausanne, Switzerland
| | - Luz Angelica Liechti
- Center for Integrative Genomics, University of Lausanne, 1015 Lausanne, Switzerland
| | - Daniel Hess
- Friedrich Miescher Institute for Biomedical Research, Maulbeerstrasse 66, 4058 Basel, Switzerland
| | - Vytautas Iesmantavicius
- Friedrich Miescher Institute for Biomedical Research, Maulbeerstrasse 66, 4058 Basel, Switzerland
| | | | - David Gatfield
- Center for Integrative Genomics, University of Lausanne, 1015 Lausanne, Switzerland
| | - Marc Bühler
- Friedrich Miescher Institute for Biomedical Research, Maulbeerstrasse 66, 4058 Basel, Switzerland; University of Basel, Petersplatz 10, 4003 Basel, Switzerland.
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17
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Zinoviev A, Hellen CUT, Pestova TV. In Vitro Characterization of the Activity of the Mammalian RNA Exosome on mRNAs in Ribosomal Translation Complexes. Methods Mol Biol 2020; 2062:327-354. [PMID: 31768984 DOI: 10.1007/978-1-4939-9822-7_16] [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] [Indexed: 10/18/2023]
Abstract
The RNA exosome is a multisubunit protein complex that exhibits a 3' to 5' exoribonuclease activity, endoribonuclease activity, and participates in a variety of RNA processing and degradation pathways in both the nucleus and the cytoplasm. Exosomes interact with various cofactors which target them to specific RNA substrates and processes. Investigation of the mechanisms by which mammalian RNA exosomes are targeted to specific RNA substrates requires the development of in vitro approaches for purification of exosomes and their co-factors, assembly of substrates and monitoring of the exosomal activity. Here, we describe protocols for in vitro reconstitution of ribosomal 80S elongation complexes on cap-labeled mRNAs and for assaying exosomal degradation of mRNAs in such complexes depending on the presence of GTPBP1, which has previously been implicated in directing the exosome to mRNA targets.
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Affiliation(s)
- Alexandra Zinoviev
- Department of Cell Biology, SUNY Downstate Health Sciences University, Brooklyn, NY, USA
| | - Christopher U T Hellen
- Department of Cell Biology, SUNY Downstate Health Sciences University, Brooklyn, NY, USA
| | - Tatyana V Pestova
- Department of Cell Biology, SUNY Downstate Health Sciences University, Brooklyn, NY, USA.
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18
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Abstract
The evolutionarily conserved RNA exosome is a multisubunit ribonuclease complex that processes and/or degrades numerous RNAs. Recently, mutations in genes encoding both structural and catalytic subunits of the RNA exosome have been linked to human disease. Mutations in the structural exosome gene EXOSC2 cause a distinct syndrome that includes retinitis pigmentosa, hearing loss, and mild intellectual disability. In contrast, mutations in the structural exosome genes EXOSC3 and EXOSC8 cause pontocerebellar hypoplasia type 1b (PCH1b) and type 1c (PCH1c), respectively, which are related autosomal recessive, neurodegenerative diseases. In addition, mutations in the structural exosome gene EXOSC9 cause a PCH-like disease with cerebellar atrophy and spinal motor neuronopathy. Finally, mutations in the catalytic exosome gene DIS3 have been linked to multiple myeloma, a neoplasm of plasma B cells. How mutations in these RNA exosome genes lead to distinct, tissue-specific diseases is not currently well understood. In this chapter, we examine the role of the RNA exosome complex in human disease and discuss the mechanisms by which mutations in different exosome subunit genes could impair RNA exosome function and give rise to diverse diseases.
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Affiliation(s)
- Milo B Fasken
- Department of Biology, RRC 1021, Emory University, Atlanta, GA, USA.
| | - Derrick J Morton
- Department of Biology, RRC 1021, Emory University, Atlanta, GA, USA
| | - Emily G Kuiper
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute, Boston, MA, USA
| | - Stephanie K Jones
- Department of Biology, RRC 1021, Emory University, Atlanta, GA, USA
- Genetics and Molecular Biology Graduate Program, Emory University, Atlanta, GA, USA
| | - Sara W Leung
- Department of Biology, RRC 1021, Emory University, Atlanta, GA, USA
| | - Anita H Corbett
- Department of Biology, RRC 1021, Emory University, Atlanta, GA, USA.
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19
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Zhang E, Khanna V, Dacheux E, Namane A, Doyen A, Gomard M, Turcotte B, Jacquier A, Fromont‐Racine M. A specialised SKI complex assists the cytoplasmic RNA exosome in the absence of direct association with ribosomes. EMBO J 2019; 38:e100640. [PMID: 31304628 PMCID: PMC6627227 DOI: 10.15252/embj.2018100640] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2018] [Revised: 04/25/2019] [Accepted: 05/13/2019] [Indexed: 11/09/2022] Open
Abstract
The Ski2-Ski3-Ski8 (SKI) complex assists the RNA exosome during the 3' to 5' degradation of cytoplasmic transcripts. Previous reports showed that the SKI complex is involved in the 3' to 5' degradation of mRNAs, including 3' untranslated regions (UTRs) and devoid of ribosomes. Paradoxically, we recently showed that the SKI complex directly interacts with ribosomes during the co-translational mRNA decay and that this interaction is necessary for its RNA degradation promoting activity. Here, we characterised a new SKI-associated factor, Ska1, that associates with a subpopulation of the SKI complex. We showed that Ska1 is specifically involved in the degradation of long 3'UTR-containing mRNAs, poorly translated mRNAs as well as other RNA regions not associated with ribosomes, such as cytoplasmic lncRNAs. We further show that the overexpression of SKA1 antagonises the SKI-ribosome association. We propose that the Ska1-SKI complex assists the cytoplasmic exosome in the absence of direct association of the SKI complex with ribosomes.
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Affiliation(s)
- Elodie Zhang
- Génétique des Interactions MacromoléculairesInstitut PasteurUMR3525 CNRSParisFrance
- Sorbonne UniversitéCollège DoctoralParisFrance
| | - Varun Khanna
- Génétique des Interactions MacromoléculairesInstitut PasteurUMR3525 CNRSParisFrance
- Hub Bioinformatique et BiostatistiqueInstitut Pasteur ‐ C3BIUSR 3756 IP CNRSParisFrance
| | - Estelle Dacheux
- Génétique des Interactions MacromoléculairesInstitut PasteurUMR3525 CNRSParisFrance
| | - Abdelkader Namane
- Génétique des Interactions MacromoléculairesInstitut PasteurUMR3525 CNRSParisFrance
| | - Antonia Doyen
- Génétique des Interactions MacromoléculairesInstitut PasteurUMR3525 CNRSParisFrance
| | - Maïté Gomard
- Génétique des Interactions MacromoléculairesInstitut PasteurUMR3525 CNRSParisFrance
| | - Bernard Turcotte
- Department of MedicineMcGill University Health CentreMontréalQCCanada
| | - Alain Jacquier
- Génétique des Interactions MacromoléculairesInstitut PasteurUMR3525 CNRSParisFrance
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20
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Li Z, Yang F, Xuan Y, Xi R, Zhao R. Pelota-interacting G protein Hbs1 is required for spermatogenesis in Drosophila. Sci Rep 2019; 9:3226. [PMID: 30824860 PMCID: PMC6397311 DOI: 10.1038/s41598-019-39530-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2018] [Accepted: 01/08/2019] [Indexed: 12/31/2022] Open
Abstract
Hbs1, which is homologous to the GTPase eRF3, is a small G protein implicated in mRNA quality control. It interacts with a translation-release factor 1-like protein Dom34/Pelota to direct decay of mRNAs with ribosomal stalls. Although both proteins are evolutionarily conserved in eukaryotes, the biological function of Hbs1 in multicellular organisms is yet to be characterized. In Drosophila, pelota is essential for the progression through meiosis during spermatogenesis and germline stem cell maintenance. Here we show that homozygous Hbs1 mutant flies are viable, female-fertile, but male-sterile, which is due to defects in meiosis and spermatid individualization, phenotypes that are also observed in pelota hypomorphic mutants. In contrast, Hbs1 mutants have no obvious defects in germline stem cell maintenance. We show that Hbs1 genetically interacts with pelota during spermatid individualization. Furthermore, Pelota with a point mutation on the putative Hbs1-binding site cannot substitute the wild type protein for normal spermatogenesis. These data suggest that Pelota forms a complex with Hbs1 to regulate multiple processes during spermatogenesis. Our results reveal a specific requirement of Hbs1 in male gametogenesis in Drosophila and indicate an essential role for the RNA surveillance complex Pelota-Hbs1 in spermatogenesis, a function that could be conserved in mammals.
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Affiliation(s)
- Zhaohui Li
- School of Life Sciences, Tsinghua University, Beijing, 100084, China.,National Institute of Biological Sciences, No. 7 Science Park Road, Zhongguancun Life Science Park, Beijing, 102206, China
| | - Fu Yang
- National Institute of Biological Sciences, No. 7 Science Park Road, Zhongguancun Life Science Park, Beijing, 102206, China
| | - Yang Xuan
- National Institute of Biological Sciences, No. 7 Science Park Road, Zhongguancun Life Science Park, Beijing, 102206, China
| | - Rongwen Xi
- National Institute of Biological Sciences, No. 7 Science Park Road, Zhongguancun Life Science Park, Beijing, 102206, China. .,Tsinghua Institute of Multidisciplinary Biomedical Research, Tsinghua University, Beijing, China.
| | - Rui Zhao
- National Institute of Biological Sciences, No. 7 Science Park Road, Zhongguancun Life Science Park, Beijing, 102206, China. .,Genomics Institute of the Novartis Research Foundation, San Diego, California, 92121, USA.
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21
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Lao JP, Ulrich KM, Johnson JR, Newton BW, Vashisht AA, Wohlschlegel JA, Krogan NJ, Toczyski DP. The Yeast DNA Damage Checkpoint Kinase Rad53 Targets the Exoribonuclease, Xrn1. G3 (BETHESDA, MD.) 2018; 8:3931-3944. [PMID: 30377154 PMCID: PMC6288840 DOI: 10.1534/g3.118.200767] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/22/2018] [Accepted: 10/15/2018] [Indexed: 12/15/2022]
Abstract
The highly conserved DNA damage response (DDR) pathway monitors the genomic integrity of the cell and protects against genotoxic stresses. The apical kinases, Mec1 and Tel1 (ATR and ATM in human, respectively), initiate the DNA damage signaling cascade through the effector kinases, Rad53 and Chk1, to regulate a variety of cellular processes including cell cycle progression, DNA damage repair, chromatin remodeling, and transcription. The DDR also regulates other cellular pathways, but direct substrates and mechanisms are still lacking. Using a mass spectrometry-based phosphoproteomic screen in Saccharomyces cerevisiae, we identified novel targets of Rad53, many of which are proteins that are involved in RNA metabolism. Of the 33 novel substrates identified, we verified that 12 are directly phosphorylated by Rad53 in vitro: Xrn1, Gcd11, Rps7b, Ded1, Cho2, Pus1, Hst1, Srv2, Set3, Snu23, Alb1, and Scp160. We further characterized Xrn1, a highly conserved 5' exoribonuclease that functions in RNA degradation and the most enriched in our phosphoproteomics screen. Phosphorylation of Xrn1 by Rad53 does not appear to affect Xrn1's intrinsic nuclease activity in vitro, but may affect its activity or specificity in vivo.
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Affiliation(s)
- Jessica P Lao
- Department of Biochemistry and Biophysics, University of California, San Francisco, CA 94158
| | - Katie M Ulrich
- Department of Biochemistry and Biophysics, University of California, San Francisco, CA 94158
| | - Jeffrey R Johnson
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, CA 94158
| | - Billy W Newton
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, CA 94158
| | - Ajay A Vashisht
- Department of Biological Chemistry, School of Medicine, University of California, Los Angeles, CA 90095
| | - James A Wohlschlegel
- Department of Biological Chemistry, School of Medicine, University of California, Los Angeles, CA 90095
| | - Nevan J Krogan
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, CA 94158
| | - David P Toczyski
- Department of Biochemistry and Biophysics, University of California, San Francisco, CA 94158
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22
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Gatica D, Hu G, Liu X, Zhang N, Williamson PR, Klionsky DJ. The Pat1-Lsm Complex Stabilizes ATG mRNA during Nitrogen Starvation-Induced Autophagy. Mol Cell 2018; 73:314-324.e4. [PMID: 30527663 DOI: 10.1016/j.molcel.2018.11.002] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Revised: 09/27/2018] [Accepted: 11/01/2018] [Indexed: 12/18/2022]
Abstract
Macroautophagy/autophagy is a key catabolic recycling pathway that requires fine-tuned regulation to prevent pathologies and preserve homeostasis. Here, we report a new post-transcriptional pathway regulating autophagy involving the Pat1-Lsm (Lsm1 to Lsm7) mRNA-binding complex. Under nitrogen-starvation conditions, Pat1-Lsm binds a specific subset of autophagy-related (ATG) transcripts and prevents their 3' to 5' degradation by the exosome complex, leading to ATG mRNA stabilization and accumulation. This process is regulated through Pat1 dephosphorylation, is necessary for the efficient expression of specific Atg proteins, and is required for robust autophagy induction during nitrogen starvation. To the best of our knowledge, this work presents the first example of ATG transcript regulation via 3' binding factors and exosomal degradation.
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Affiliation(s)
- Damián Gatica
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA; Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA
| | - Guowu Hu
- Laboratory of Clinical Immunology and Microbiology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Xu Liu
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA; Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA
| | - Nannan Zhang
- Laboratory of Clinical Immunology and Microbiology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Peter R Williamson
- Laboratory of Clinical Immunology and Microbiology, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892, USA
| | - Daniel J Klionsky
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA; Life Sciences Institute, University of Michigan, Ann Arbor, MI 48109, USA.
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23
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Kalisiak K, Kuliński TM, Tomecki R, Cysewski D, Pietras Z, Chlebowski A, Kowalska K, Dziembowski A. A short splicing isoform of HBS1L links the cytoplasmic exosome and SKI complexes in humans. Nucleic Acids Res 2018; 45:2068-2080. [PMID: 28204585 PMCID: PMC5389692 DOI: 10.1093/nar/gkw862] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2016] [Revised: 08/25/2016] [Accepted: 09/20/2016] [Indexed: 12/18/2022] Open
Abstract
The exosome complex is a major eukaryotic exoribonuclease that requires the SKI complex for its activity in the cytoplasm. In yeast, the Ski7 protein links both complexes, whereas a functional equivalent of the Ski7 has remained unknown in the human genome. Proteomic analysis revealed that a previously uncharacterized short splicing isoform of HBS1L (HBS1LV3) is the long-sought factor linking the exosome and SKI complexes in humans. In contrast, the canonical HBS1L variant, HBS1LV1, which acts as a ribosome dissociation factor, does not associate with the exosome and instead interacts with the mRNA surveillance factor PELOTA. Interestingly, both HBS1LV1 and HBS1LV3 interact with the SKI complex and HBS1LV1 seems to antagonize SKI/exosome supercomplex formation. HBS1LV3 contains a unique C-terminal region of unknown structure, with a conserved RxxxFxxxL motif responsible for exosome binding and may interact with the exosome core subunit RRP43 in a way that resembles the association between Rrp6 RNase and Rrp43 in yeast. HBS1LV3 or the SKI complex helicase (SKI2W) depletion similarly affected the transcriptome, deregulating multiple genes. Furthermore, half-lives of representative upregulated mRNAs were increased, supporting the involvement of HBS1LV3 and SKI2W in the same mRNA degradation pathway, essential for transcriptome homeostasis in the cytoplasm.
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Affiliation(s)
- Katarzyna Kalisiak
- Laboratory of RNA Biology and Functional Genomics, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawinskiego 5a, 02-106 Warsaw, Poland
- Institute of Genetics and Biotechnology, Faculty of Biology, University of Warsaw, Pawinskiego 5a, 02-106 Warsaw, Poland
| | - Tomasz M. Kuliński
- Laboratory of RNA Biology and Functional Genomics, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawinskiego 5a, 02-106 Warsaw, Poland
- Institute of Genetics and Biotechnology, Faculty of Biology, University of Warsaw, Pawinskiego 5a, 02-106 Warsaw, Poland
| | - Rafał Tomecki
- Laboratory of RNA Biology and Functional Genomics, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawinskiego 5a, 02-106 Warsaw, Poland
- Institute of Genetics and Biotechnology, Faculty of Biology, University of Warsaw, Pawinskiego 5a, 02-106 Warsaw, Poland
| | - Dominik Cysewski
- Laboratory of RNA Biology and Functional Genomics, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawinskiego 5a, 02-106 Warsaw, Poland
- Institute of Genetics and Biotechnology, Faculty of Biology, University of Warsaw, Pawinskiego 5a, 02-106 Warsaw, Poland
| | - Zbigniew Pietras
- Laboratory of RNA Biology and Functional Genomics, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawinskiego 5a, 02-106 Warsaw, Poland
- Institute of Genetics and Biotechnology, Faculty of Biology, University of Warsaw, Pawinskiego 5a, 02-106 Warsaw, Poland
- International Institute of Molecular and Cell Biology in Warsaw, Ks. Trojdena 4, 02-109 Warsaw, Poland
| | - Aleksander Chlebowski
- Laboratory of RNA Biology and Functional Genomics, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawinskiego 5a, 02-106 Warsaw, Poland
- Institute of Genetics and Biotechnology, Faculty of Biology, University of Warsaw, Pawinskiego 5a, 02-106 Warsaw, Poland
| | - Katarzyna Kowalska
- Laboratory of RNA Biology and Functional Genomics, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawinskiego 5a, 02-106 Warsaw, Poland
- Institute of Genetics and Biotechnology, Faculty of Biology, University of Warsaw, Pawinskiego 5a, 02-106 Warsaw, Poland
| | - Andrzej Dziembowski
- Laboratory of RNA Biology and Functional Genomics, Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawinskiego 5a, 02-106 Warsaw, Poland
- Institute of Genetics and Biotechnology, Faculty of Biology, University of Warsaw, Pawinskiego 5a, 02-106 Warsaw, Poland
- To whom correspondence should be addressed. Tel: +48 22 5922033; Fax: +48 22 6584176;
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24
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Conservation of mRNA quality control factor Ski7 and its diversification through changes in alternative splicing and gene duplication. Proc Natl Acad Sci U S A 2018; 115:E6808-E6816. [PMID: 29967155 DOI: 10.1073/pnas.1801997115] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Eukaryotes maintain fidelity of gene expression by preferential degradation of aberrant mRNAs that arise by errors in RNA processing reactions. In Saccharomyces cerevisiae, Ski7 plays an important role in this mRNA quality control by mediating mRNA degradation by the RNA exosome. Ski7 was initially thought to be restricted to Saccharomyces cerevisiae and close relatives because the SKI7 gene and its paralog HBS1 arose by whole genome duplication (WGD) in a recent ancestor. We have recently shown that the preduplication gene was alternatively spliced and that Ski7 function predates WGD. Here, we use transcriptome analysis of diverse eukaryotes to show that diverse eukaryotes use alternative splicing of SKI7/HBS1 to encode two proteins. Although alternative splicing affects the same intrinsically disordered region of the protein, the pattern of splice site usage varies. This alternative splicing event arose in an early eukaryote that is a common ancestor of plants, animals, and fungi. Remarkably, through changes in alternative splicing and gene duplication, the Ski7 protein has diversified such that different species express one of four distinct Ski7-like proteins. We also show experimentally that the Saccharomyces cerevisiae SKI7 gene has undergone multiple changes that are incompatible with the Hbs1 function and may also have undergone additional changes to optimize mRNA quality control. The combination of transcriptome analysis in diverse eukaryotes and genetic analysis in yeast clarifies the mechanism by which a Ski7-like protein is expressed across eukaryotes and provides a unique view of changes in alternative splicing patterns of one gene over long evolutionary time.
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25
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Falcone C, Mazzoni C. RNA stability and metabolism in regulated cell death, aging and diseases. FEMS Yeast Res 2018; 18:4978431. [DOI: 10.1093/femsyr/foy050] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2018] [Accepted: 04/17/2018] [Indexed: 12/13/2022] Open
Affiliation(s)
- Claudio Falcone
- Pasteur Institute-Cenci Bolognetti Foundation, Department of Biology and Biotechnology “Charles Darwin”, Sapienza University of Rome, Piazzale Aldo Moro 5, 00185-Rome, Italy
| | - Cristina Mazzoni
- Pasteur Institute-Cenci Bolognetti Foundation, Department of Biology and Biotechnology “Charles Darwin”, Sapienza University of Rome, Piazzale Aldo Moro 5, 00185-Rome, Italy
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26
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Morton DJ, Kuiper EG, Jones SK, Leung SW, Corbett AH, Fasken MB. The RNA exosome and RNA exosome-linked disease. RNA (NEW YORK, N.Y.) 2018; 24:127-142. [PMID: 29093021 PMCID: PMC5769741 DOI: 10.1261/rna.064626.117] [Citation(s) in RCA: 99] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
The RNA exosome is an evolutionarily conserved, ribonuclease complex that is critical for both processing and degradation of a variety of RNAs. Cofactors that associate with the RNA exosome likely dictate substrate specificity for this complex. Recently, mutations in genes encoding both structural subunits of the RNA exosome and its cofactors have been linked to human disease. Mutations in the RNA exosome genes EXOSC3 and EXOSC8 cause pontocerebellar hypoplasia type 1b (PCH1b) and type 1c (PCH1c), respectively, which are similar autosomal-recessive, neurodegenerative diseases. Mutations in the RNA exosome gene EXOSC2 cause a distinct syndrome with various tissue-specific phenotypes including retinitis pigmentosa and mild intellectual disability. Mutations in genes that encode RNA exosome cofactors also cause tissue-specific diseases with complex phenotypes. How mutations in these genes give rise to distinct, tissue-specific diseases is not clear. In this review, we discuss the role of the RNA exosome complex and its cofactors in human disease, consider the amino acid changes that have been implicated in disease, and speculate on the mechanisms by which exosome gene mutations could underlie dysfunction and disease.
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Affiliation(s)
- Derrick J Morton
- Department of Biology, Emory University, NE, Atlanta, Georgia 30322, USA
| | - Emily G Kuiper
- Department of Cancer Immunology and Virology, Dana-Farber Cancer Institute, Boston, Massachusetts 02215, USA
| | - Stephanie K Jones
- Department of Biology, Emory University, NE, Atlanta, Georgia 30322, USA
- Genetics and Molecular Biology Graduate Program, Emory University, NE, Atlanta, Georgia 30322, USA
| | - Sara W Leung
- Department of Biology, Emory University, NE, Atlanta, Georgia 30322, USA
| | - Anita H Corbett
- Department of Biology, Emory University, NE, Atlanta, Georgia 30322, USA
| | - Milo B Fasken
- Department of Biology, Emory University, NE, Atlanta, Georgia 30322, USA
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27
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Jamar NH, Kritsiligkou P, Grant CM. The non-stop decay mRNA surveillance pathway is required for oxidative stress tolerance. Nucleic Acids Res 2017; 45:6881-6893. [PMID: 28472342 PMCID: PMC5499853 DOI: 10.1093/nar/gkx306] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Accepted: 04/12/2017] [Indexed: 01/09/2023] Open
Abstract
Reactive oxygen species (ROS) are toxic by-products of normal aerobic metabolism. ROS can damage mRNAs and the translational apparatus resulting in translational defects and aberrant protein production. Three mRNA quality control systems monitor mRNAs for translational errors: nonsense-mediated decay, non-stop decay (NSD) and no-go decay (NGD) pathways. Here, we show that factors required for the recognition of NSD substrates and components of the SKI complex are required for oxidant tolerance. We found an overlapping requirement for Ski7, which bridges the interaction between the SKI complex and the exosome, and NGD components (Dom34/Hbs1) which have been shown to function in both NSD and NGD. We show that ski7 dom34 and ski7 hbs1 mutants are sensitive to hydrogen peroxide stress and accumulate an NSD substrate. We further show that NSD substrates are generated during ROS exposure as a result of aggregation of the Sup35 translation termination factor, which increases stop codon read-through allowing ribosomes to translate into the 3΄-end of mRNAs. Overexpression of Sup35 decreases stop codon read-through and rescues oxidant tolerance consistent with this model. Our data reveal an unanticipated requirement for the NSD pathway during oxidative stress conditions which prevents the production of aberrant proteins from NSD mRNAs.
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Affiliation(s)
- Nur H Jamar
- The University of Manchester, Faculty of Biology, Medicine and Health, Manchester M13 9PT, UK.,School of Biosciences and Biotechnology, Faculty of Science and Technology, Universiti Kebangsaan Malaysia, 43600 Bangi, Malaysia
| | - Paraskevi Kritsiligkou
- The University of Manchester, Faculty of Biology, Medicine and Health, Manchester M13 9PT, UK
| | - Chris M Grant
- The University of Manchester, Faculty of Biology, Medicine and Health, Manchester M13 9PT, UK
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28
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Vaškovičová K, Awadová T, Veselá P, Balážová M, Opekarová M, Malinsky J. mRNA decay is regulated via sequestration of the conserved 5′-3′ exoribonuclease Xrn1 at eisosome in yeast. Eur J Cell Biol 2017; 96:591-599. [DOI: 10.1016/j.ejcb.2017.05.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2017] [Revised: 04/07/2017] [Accepted: 05/02/2017] [Indexed: 01/08/2023] Open
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29
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Zinder JC, Lima CD. Targeting RNA for processing or destruction by the eukaryotic RNA exosome and its cofactors. Genes Dev 2017; 31:88-100. [PMID: 28202538 PMCID: PMC5322736 DOI: 10.1101/gad.294769.116] [Citation(s) in RCA: 151] [Impact Index Per Article: 21.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
In this review, Zinder and Lima highlight recent advances that have illuminated roles for the RNA exosome and its cofactors in specific biological pathways, alongside studies that attempted to dissect these activities through structural and biochemical characterization of nuclear and cytoplasmic RNA exosome complexes. The eukaryotic RNA exosome is an essential and conserved protein complex that can degrade or process RNA substrates in the 3′-to-5′ direction. Since its discovery nearly two decades ago, studies have focused on determining how the exosome, along with associated cofactors, achieves the demanding task of targeting particular RNAs for degradation and/or processing in both the nucleus and cytoplasm. In this review, we highlight recent advances that have illuminated roles for the RNA exosome and its cofactors in specific biological pathways, alongside studies that attempted to dissect these activities through structural and biochemical characterization of nuclear and cytoplasmic RNA exosome complexes.
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Affiliation(s)
- John C Zinder
- Tri-Institutional Training Program in Chemical Biology, Memorial Sloan Kettering Cancer Center, New York, New York 10065, USA.,Structural Biology Program, Sloan Kettering Institute, New York, New York, 10065, USA
| | - Christopher D Lima
- Structural Biology Program, Sloan Kettering Institute, New York, New York, 10065, USA.,Howard Hughes Medical Institute, New York, New York, 10065 USA
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30
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Das S, Sarkar D, Das B. The interplay between transcription and mRNA degradation in Saccharomyces cerevisiae. MICROBIAL CELL 2017; 4:212-228. [PMID: 28706937 PMCID: PMC5507684 DOI: 10.15698/mic2017.07.580] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
The cellular transcriptome is shaped by both the rates of mRNA synthesis in the nucleus and mRNA degradation in the cytoplasm under a specified condition. The last decade witnessed an exciting development in the field of post-transcriptional regulation of gene expression which underscored a strong functional coupling between the transcription and mRNA degradation. The functional integration is principally mediated by a group of specialized promoters and transcription factors that govern the stability of their cognate transcripts by “marking” them with a specific factor termed “coordinator.” The “mark” carried by the message is later decoded in the cytoplasm which involves the stimulation of one or more mRNA-decay factors, either directly by the “coordinator” itself or in an indirect manner. Activation of the decay factor(s), in turn, leads to the alteration of the stability of the marked message in a selective fashion. Thus, the integration between mRNA synthesis and decay plays a potentially significant role to shape appropriate gene expression profiles during cell cycle progression, cell division, cellular differentiation and proliferation, stress, immune and inflammatory responses, and may enhance the rate of biological evolution.
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Affiliation(s)
- Subhadeep Das
- Department of Life Science and Biotechnology, Jadavpur University, Kolkata, India
| | - Debasish Sarkar
- Present Address: Laboratory of Molecular Genetics, Wadsworth Center, New York State Department of Health, Albany, NY 12201-2002, USA
| | - Biswadip Das
- Department of Life Science and Biotechnology, Jadavpur University, Kolkata, India
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31
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An mRNA decapping mutant deficient in P body assembly limits mRNA stabilization in response to osmotic stress. Sci Rep 2017; 7:44395. [PMID: 28290514 PMCID: PMC5349606 DOI: 10.1038/srep44395] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2016] [Accepted: 02/07/2017] [Indexed: 01/19/2023] Open
Abstract
Yeast is exposed to changing environmental conditions and must adapt its genetic program to provide a homeostatic intracellular environment. An important stress for yeast in the wild is high osmolarity. A key response to this stress is increased mRNA stability primarily by the inhibition of deadenylation. We previously demonstrated that mutations in decapping activators (edc3∆ lsm4∆C), which result in defects in P body assembly, can destabilize mRNA under unstressed conditions. We wished to examine whether mRNA would be destabilized in the edc3∆ lsm4∆C mutant as compared to the wild-type in response to osmotic stress, when P bodies are intense and numerous. Our results show that the edc3∆ lsm4∆C mutant limits the mRNA stability in response to osmotic stress, while the magnitude of stabilization was similar as compared to the wild-type. The reduced mRNA stability in the edc3∆ lsm4∆C mutant was correlated with a shorter PGK1 poly(A) tail. Similarly, the MFA2 mRNA was more rapidly deadenylated as well as significantly stabilized in the ccr4∆ deadenylation mutant in the edc3∆ lsm4∆C background. These results suggest a role for these decapping factors in stabilizing mRNA and may implicate P bodies as sites of reduced mRNA degradation.
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32
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Laffleur B, Basu U, Lim J. RNA Exosome and Non-coding RNA-Coupled Mechanisms in AID-Mediated Genomic Alterations. J Mol Biol 2017; 429:3230-3241. [PMID: 28069372 DOI: 10.1016/j.jmb.2016.12.021] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2016] [Revised: 12/21/2016] [Accepted: 12/27/2016] [Indexed: 12/31/2022]
Abstract
The eukaryotic RNA exosome is a well-conserved protein complex with ribonuclease activity implicated in RNA metabolism. Various families of non-coding RNAs have been identified as substrates of the complex, underscoring its role as a non-coding RNA processing/degradation unit. However, the role of RNA exosome and its RNA processing activity on DNA mutagenesis/alteration events have not been investigated until recently. B lymphocytes use two DNA alteration mechanisms, class switch recombination (CSR) and somatic hypermutation (SHM), to re-engineer their antibody gene expressing loci until a tailored antibody gene for a specific antigen is satisfactorily generated. CSR and SHM require the essential activity of the DNA activation-induced cytidine deaminase (AID). Causing collateral damage to the B-cell genome during CSR and SHM, AID induces unwanted (and sometimes oncogenic) mutations at numerous non-immunoglobulin gene sequences. Recent studies have revealed that AID's DNA mutator activity is regulated by the RNA exosome complex, thus providing an example of a mechanism that relates DNA mutagenesis to RNA processing. Here, we review the emergent functions of RNA exosome during CSR, SHM, and other chromosomal alterations in B cells, and discuss implications relevant to mechanisms that maintain B-cell genomic integrity.
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Affiliation(s)
- Brice Laffleur
- Department of Microbiology and Immunology, College of Physicians and Surgeons, Columbia University, New York, NY, USA
| | - Uttiya Basu
- Department of Microbiology and Immunology, College of Physicians and Surgeons, Columbia University, New York, NY, USA.
| | - Junghyun Lim
- Department of Microbiology and Immunology, College of Physicians and Surgeons, Columbia University, New York, NY, USA
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33
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Inada T. The Ribosome as a Platform for mRNA and Nascent Polypeptide Quality Control. Trends Biochem Sci 2017; 42:5-15. [DOI: 10.1016/j.tibs.2016.09.005] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2016] [Revised: 09/05/2016] [Accepted: 09/13/2016] [Indexed: 11/28/2022]
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34
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Falk S, Finogenova K, Melko M, Benda C, Lykke-Andersen S, Jensen TH, Conti E. Structure of the RBM7-ZCCHC8 core of the NEXT complex reveals connections to splicing factors. Nat Commun 2016; 7:13573. [PMID: 27905398 PMCID: PMC5146272 DOI: 10.1038/ncomms13573] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2016] [Accepted: 10/13/2016] [Indexed: 01/24/2023] Open
Abstract
The eukaryotic RNA exosome participates extensively in RNA processing and degradation. In human cells, three accessory factors (RBM7, ZCCHC8 and hMTR4) interact to form the nuclear exosome targeting (NEXT) complex, which directs a subset of non-coding RNAs for exosomal degradation. Here we elucidate how RBM7 is incorporated in the NEXT complex. We identify a proline-rich segment of ZCCHC8 as the interaction site for the RNA-recognition motif (RRM) of RBM7 and present the crystal structure of the corresponding complex at 2.0 Å resolution. On the basis of the structure, we identify a proline-rich segment within the splicing factor SAP145 with strong similarity to ZCCHC8. We show that this segment of SAP145 not only binds the RRM region of another splicing factor SAP49 but also the RRM of RBM7. These dual interactions of RBM7 with the exosome and the spliceosome suggest a model whereby NEXT might recruit the exosome to degrade intronic RNAs. RBM7 and ZCCHC8 are two core subunits of the Nuclear Exosome Targeting complex, which regulates the degradation of selected non-coding RNAs in human cells. Here, the authors use structural and biochemical methods to show how ZCCHC8 recruits RBM7 in the complex, leaving the RNA binding site accessible and revealing possible implications for splicing.
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Affiliation(s)
- Sebastian Falk
- Department of Structural Cell Biology, Max-Planck-Institute of Biochemistry, Am Klopferspitz 18, D-82152 Martinsried, Germany
| | - Ksenia Finogenova
- Department of Structural Cell Biology, Max-Planck-Institute of Biochemistry, Am Klopferspitz 18, D-82152 Martinsried, Germany
| | - Mireille Melko
- Department of Molecular Biology and Genetics, Aarhus University, C.F. Møllers Alle 3, 8000C Aarhus, Denmark
| | - Christian Benda
- Department of Structural Cell Biology, Max-Planck-Institute of Biochemistry, Am Klopferspitz 18, D-82152 Martinsried, Germany
| | - Søren Lykke-Andersen
- Department of Molecular Biology and Genetics, Aarhus University, C.F. Møllers Alle 3, 8000C Aarhus, Denmark
| | - Torben Heick Jensen
- Department of Molecular Biology and Genetics, Aarhus University, C.F. Møllers Alle 3, 8000C Aarhus, Denmark
| | - Elena Conti
- Department of Structural Cell Biology, Max-Planck-Institute of Biochemistry, Am Klopferspitz 18, D-82152 Martinsried, Germany
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35
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Wolf I, Bouquet C, Melchers F. cDNA-library testing identifies transforming genes cooperating with c-myc in mouse pre-B cells. Eur J Immunol 2016; 46:2555-2565. [PMID: 27538750 DOI: 10.1002/eji.201646419] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2016] [Revised: 06/28/2016] [Accepted: 08/16/2016] [Indexed: 12/12/2022]
Abstract
While c-myc often contributes to the generation of B cell transformation, its transgenic overexpression alone does not lead to full transformation of B-lineage cells. Synergistically acting second genes must cooperate. Here, we constructed doxycycline-inducible cDNA-libraries from pre-B cell mRNA. These libraries were retrovirally transduced as single copies into single cells and overexpressed in fetal-liver-derived c-myc-overexpressing pre-B cell lines. We scored transformation by survival and/or expansion of differentiating B-lineage cells in vitro and in vivo. Only one double c-myc/cDNA-library-expressing cell line was found in less than 5 × 106 library-transduced pre-B cells surviving and expressing a cDNA-library-derived transcript in vitro. This transcript was identified as a shortened form of the Exosc1 gene, encoding the RNA exosome complex component CSL4. Transplantations of double c-myc/Exosc1 short-form- or c-myc/Exosc1 full-length-transgenic cells into Rag1-/- mice resulted in survival, differentiation to CD19+ CD93- sIgM+ CD5low/- CD11b+ mature B1 cells and, surprisingly, also vigorous expansion in vivo. Strikingly, after transplantations of c-myc/cDNA-library pre-BI cells the frequencies of double-transgenic pre-B cells and their differentiated progeny, expanding in vivo to heterogeneous phenotypes, was at least tenfold higher than in vitro. In a first analysis Ptprcap, Cacybp, Ndufs7, Rpl18a, and Rpl35a were identified. This suggests a strong influence of the host on B-cell transformation.
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Affiliation(s)
- Inge Wolf
- Max Planck Fellow Research Group, "Lymphocyte Development", Max Planck Institute for Infection Biology, Berlin, Germany.
| | - Corinne Bouquet
- Max Planck Fellow Research Group, "Lymphocyte Development", Max Planck Institute for Infection Biology, Berlin, Germany
| | - Fritz Melchers
- Max Planck Fellow Research Group, "Lymphocyte Development", Max Planck Institute for Infection Biology, Berlin, Germany
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36
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Insight into the RNA Exosome Complex Through Modeling Pontocerebellar Hypoplasia Type 1b Disease Mutations in Yeast. Genetics 2016; 205:221-237. [PMID: 27777260 DOI: 10.1534/genetics.116.195917] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2016] [Accepted: 10/19/2016] [Indexed: 11/18/2022] Open
Abstract
Pontocerebellar hypoplasia type 1b (PCH1b) is an autosomal recessive disorder that causes cerebellar hypoplasia and spinal motor neuron degeneration, leading to mortality in early childhood. PCH1b is caused by mutations in the RNA exosome subunit gene, EXOSC3 The RNA exosome is an evolutionarily conserved complex, consisting of nine different core subunits, and one or two 3'-5' exoribonuclease subunits, that mediates several RNA degradation and processing steps. The goal of this study is to assess the functional consequences of the amino acid substitutions that have been identified in EXOSC3 in PCH1b patients. To analyze these EXOSC3 substitutions, we generated the corresponding amino acid substitutions in the Saccharomyces cerevisiae ortholog of EXOSC3, Rrp40 We find that the rrp40 variants corresponding to EXOSC3-G31A and -D132A do not affect yeast function when expressed as the sole copy of the essential Rrp40 protein. In contrast, the rrp40-W195R variant, corresponding to EXOSC3-W238R in PCH1b patients, impacts cell growth and RNA exosome function when expressed as the sole copy of Rrp40 The rrp40-W195R protein is unstable, and does not associate efficiently with the RNA exosome in cells that also express wild-type Rrp40 Consistent with these findings in yeast, the levels of mouse EXOSC3 variants are reduced compared to wild-type EXOSC3 in a neuronal cell line. These data suggest that cells possess a mechanism for optimal assembly of functional RNA exosome complex that can discriminate between wild-type and variant exosome subunits. Budding yeast can therefore serve as a useful tool to understand the molecular defects in the RNA exosome caused by PCH1b-associated amino acid substitutions in EXOSC3, and potentially extending to disease-associated substitutions in other exosome subunits.
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37
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Horikawa W, Endo K, Wada M, Ito K. Mutations in the G-domain of Ski7 cause specific dysfunction in non-stop decay. Sci Rep 2016; 6:29295. [PMID: 27381255 PMCID: PMC4933942 DOI: 10.1038/srep29295] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2015] [Accepted: 06/17/2016] [Indexed: 11/10/2022] Open
Abstract
Ski7 functions as a cofactor in both normal mRNA turnover and non-stop mRNA decay (NSD) mRNA surveillance in budding yeast. The N-terminal region of Ski7 (Ski7N) interacts with the ski-complex and the exosome. The C-terminal region of Ski7 (Ski7C) binds guanine nucleotides and shares overall sequence and structural homology with the proteins of the translational GTPase superfamily, especially the tRNA/tRNA-mimic carrier protein subfamilies such as EF1α, eRF3, and Hbs1. Previous reports showed that Ski7N polypeptide functions adequately in vivo, while Ski7C, if any, only slightly. Furthermore, Ski7C does not exhibit GTP-hydrolysing activities under normal conditions. Therefore, the physiological and functional significance of the conserved Ski7C is unclear. Here, we report strong genetic evidence suggesting differential roles for Ski7N and Ski7C in normal and specific mRNA turnover pathways by creating/isolating mutations in both Ski7N and Ski7C conserved motifs using indicator yeast strains. We concluded that Ski7C participates in mRNA surveillance as a regulatory module competitively with the Hbs1/Dom34 complex. Our results provide insights into the molecular regulatory mechanisms underlying mRNA surveillance.
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Affiliation(s)
- Wataru Horikawa
- Department of Computational Biology and Medical Sciences, Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa-city, Chiba 277-8562, Japan.,Institute for Virus Research, Kyoto University, Kyoto 606-8507, Japan
| | - Kei Endo
- Department of Computational Biology and Medical Sciences, Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa-city, Chiba 277-8562, Japan
| | - Miki Wada
- Department of Computational Biology and Medical Sciences, Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa-city, Chiba 277-8562, Japan.,Technical office, The Institute of Medical Science, The University of Tokyo, Minato-ku, Tokyo 108-8639, Japan
| | - Koichi Ito
- Department of Computational Biology and Medical Sciences, Graduate School of Frontier Sciences, The University of Tokyo, Kashiwa-city, Chiba 277-8562, Japan
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38
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Kowalinski E, Kögel A, Ebert J, Reichelt P, Stegmann E, Habermann B, Conti E. Structure of a Cytoplasmic 11-Subunit RNA Exosome Complex. Mol Cell 2016; 63:125-34. [PMID: 27345150 PMCID: PMC4942675 DOI: 10.1016/j.molcel.2016.05.028] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2016] [Revised: 04/26/2016] [Accepted: 05/18/2016] [Indexed: 10/28/2022]
Abstract
The RNA exosome complex associates with nuclear and cytoplasmic cofactors to mediate the decay, surveillance, or processing of a wide variety of transcripts. In the cytoplasm, the conserved core of the exosome (Exo10) functions together with the conserved Ski complex. The interaction of S. cerevisiae Exo10 and Ski is not direct but requires a bridging cofactor, Ski7. Here, we report the 2.65 Å resolution structure of S. cerevisiae Exo10 bound to the interacting domain of Ski7. Extensive hydrophobic interactions rationalize the high affinity and stability of this complex, pointing to Ski7 as a constitutive component of the cytosolic exosome. Despite the absence of sequence homology, cytoplasmic Ski7 and nuclear Rrp6 bind Exo10 using similar surfaces and recognition motifs. Knowledge of the interacting residues in the yeast complexes allowed us to identify a splice variant of human HBS1-Like as a Ski7-like exosome-binding protein, revealing the evolutionary conservation of this cytoplasmic cofactor.
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Affiliation(s)
- Eva Kowalinski
- Department of Structural Cell Biology, Max Planck Institute of Biochemistry, Am Klopferspitz 18, 82152 Martinsried, Germany
| | - Alexander Kögel
- Department of Structural Cell Biology, Max Planck Institute of Biochemistry, Am Klopferspitz 18, 82152 Martinsried, Germany
| | - Judith Ebert
- Department of Structural Cell Biology, Max Planck Institute of Biochemistry, Am Klopferspitz 18, 82152 Martinsried, Germany
| | - Peter Reichelt
- Department of Structural Cell Biology, Max Planck Institute of Biochemistry, Am Klopferspitz 18, 82152 Martinsried, Germany
| | - Elisabeth Stegmann
- Department of Structural Cell Biology, Max Planck Institute of Biochemistry, Am Klopferspitz 18, 82152 Martinsried, Germany
| | - Bianca Habermann
- Computational Biology, Max Planck Institute of Biochemistry, Am Klopferspitz 18, 82152 Martinsried, Germany
| | - Elena Conti
- Department of Structural Cell Biology, Max Planck Institute of Biochemistry, Am Klopferspitz 18, 82152 Martinsried, Germany.
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39
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Georis I, Isabelle G, Tate JJ, Vierendeels F, Cooper TG, Dubois E. Premature termination of GAT1 transcription explains paradoxical negative correlation between nitrogen-responsive mRNA, but constitutive low-level protein production. RNA Biol 2016; 12:824-37. [PMID: 26259534 PMCID: PMC4615157 DOI: 10.1080/15476286.2015.1058476] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
The first step in executing the genetic program of a cell is production of mRNA. In yeast, almost every gene is transcribed as multiple distinct isoforms, differing at their 5′ and/or 3′ termini. However, the implications and functional significance of the transcriptome-wide diversity of mRNA termini remains largely unexplored. In this paper, we show that the GAT1 gene, encoding a transcriptional activator of nitrogen-responsive catabolic genes, produces a variety of mRNAs differing in their 5′ and 3′ termini. Alternative transcription initiation leads to the constitutive, low level production of 2 full length proteins differing in their N-termini, whereas premature transcriptional termination generates a short, highly nitrogen catabolite repression- (NCR-) sensitive transcript that, as far as we can determine, is not translated under the growth conditions we used, but rather likely protects the cell from excess Gat1.
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Affiliation(s)
| | - Georis Isabelle
- a Yeast Physiology ; Institut de Recherches Microbiologiques J. M. Wiame ; Laboratoire de Microbiologie Université Libre de Bruxelles ; Brussels , Belgium
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40
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Rodríguez-Galán O, García-Gómez JJ, Kressler D, de la Cruz J. Immature large ribosomal subunits containing the 7S pre-rRNA can engage in translation in Saccharomyces cerevisiae. RNA Biol 2016; 12:838-46. [PMID: 26151772 DOI: 10.1080/15476286.2015.1058477] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Evolution has provided eukaryotes with mechanisms that impede immature and/or aberrant ribosomes to engage in translation. These mechanisms basically either prevent the nucleo-cytoplasmic export of these particles or, once in the cytoplasm, the release of associated assembly factors, which interfere with the binding of translation initiation factors and/or the ribosomal subunit joining. We have previously shown that aberrant yeast 40S ribosomal subunits containing the 20S pre-rRNA can engage in translation. In this study, we describe that cells harbouring the dob1-1 allele, encoding a mutated version of the exosome-assisting RNA helicase Mtr4, accumulate otherwise nuclear pre-60S ribosomal particles containing the 7S pre-rRNA in the cytoplasm. Polysome fractionation analyses revealed that these particles are competent for translation and do not induce elongation stalls. This phenomenon is rather specific since most mutations in other exosome components or co-factors, impairing the 3' end processing of the mature 5.8S rRNA, accumulate 7S pre-rRNAs in the nucleus. In addition, we confirm that pre-60S ribosomal particles containing either 5.8S + 30 or 5.8S + 5 pre-rRNAs also engage in translation elongation. We propose that 7S pre-rRNA processing is not strictly required for pre-60S r-particle export and that, upon arrival in the cytoplasm, there is no specific mechanism to prevent translation by premature pre-60S r-particles containing 3' extended forms of mature 5.8S rRNA.
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Affiliation(s)
- Olga Rodríguez-Galán
- a Instituto de Biomedicina de Sevilla ; Hospital Universitario Virgen del Rocío/CSIC/Universidad de Sevilla ; Seville , Spain
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41
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Huang HY, Hopper AK. Multiple Layers of Stress-Induced Regulation in tRNA Biology. Life (Basel) 2016; 6:life6020016. [PMID: 27023616 PMCID: PMC4931453 DOI: 10.3390/life6020016] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2016] [Revised: 03/14/2016] [Accepted: 03/17/2016] [Indexed: 01/28/2023] Open
Abstract
tRNAs are the fundamental components of the translation machinery as they deliver amino acids to the ribosomes during protein synthesis. Beyond their essential function in translation, tRNAs also function in regulating gene expression, modulating apoptosis and several other biological processes. There are multiple layers of regulatory mechanisms in each step of tRNA biogenesis. For example, tRNA 3′ trailer processing is altered upon nutrient stress; tRNA modification is reprogrammed under various stresses; nuclear accumulation of tRNAs occurs upon nutrient deprivation; tRNA halves accumulate upon oxidative stress. Here we address how environmental stresses can affect nearly every step of tRNA biology and we describe the possible regulatory mechanisms that influence the function or expression of tRNAs under stress conditions.
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Affiliation(s)
- Hsiao-Yun Huang
- Department of Biology, Indiana University, 915 E third St., Myers 300, Bloomington, IN 47405, USA.
| | - Anita K Hopper
- Department of Molecular Genetics and Center for RNA Biology, The Ohio State University, Columbus, OH 43210, USA.
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42
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Macias S, Cordiner RA, Gautier P, Plass M, Cáceres JF. DGCR8 Acts as an Adaptor for the Exosome Complex to Degrade Double-Stranded Structured RNAs. Mol Cell 2015; 60:873-85. [PMID: 26687677 PMCID: PMC4691244 DOI: 10.1016/j.molcel.2015.11.011] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2014] [Revised: 07/16/2015] [Accepted: 11/06/2015] [Indexed: 01/18/2023]
Abstract
The Microprocessor complex (DGCR8/Drosha) is required for microRNA (miRNA) biogenesis but also binds and regulates the stability of several types of cellular RNAs. Of particular interest, DGCR8 controls the stability of mature small nucleolar RNA (snoRNA) transcripts independently of Drosha, suggesting the existence of alternative DGCR8 complex(es) with other nucleases to process a variety of cellular RNAs. Here, we found that DGCR8 copurifies with subunits of the nuclear exosome, preferentially associating with its hRRP6-containing nucleolar form. Importantly, we demonstrate that DGCR8 is essential for the recruitment of the exosome to snoRNAs and to human telomerase RNA. In addition, we show that the DGCR8/exosome complex controls the stability of the human telomerase RNA component (hTR/TERC). Altogether, these data suggest that DGCR8 acts as an adaptor to recruit the exosome complex to structured RNAs and induce their degradation. DGCR8 forms an alternative complex with the hRRP6-containing form of the exosome DGCR8 acts as an adaptor to recruit the exosome to target structured RNAs The DGCR8/hRRP6 complex also controls the stability of human telomerase RNA
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Affiliation(s)
- Sara Macias
- Medical Research Council Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Western General Hospital, Edinburgh EH4 2XU, UK
| | - Ross A Cordiner
- Medical Research Council Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Western General Hospital, Edinburgh EH4 2XU, UK
| | - Philippe Gautier
- Medical Research Council Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Western General Hospital, Edinburgh EH4 2XU, UK
| | - Mireya Plass
- Department of Biology, Center for Computational and Applied Transcriptomics, University of Copenhagen, Ole Maaloes Vej 5, 2200 Copenhagen, Denmark
| | - Javier F Cáceres
- Medical Research Council Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Western General Hospital, Edinburgh EH4 2XU, UK.
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43
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Kowalinski E, Schuller A, Green R, Conti E. Saccharomyces cerevisiae Ski7 Is a GTP-Binding Protein Adopting the Characteristic Conformation of Active Translational GTPases. Structure 2015; 23:1336-43. [PMID: 26051716 PMCID: PMC4509514 DOI: 10.1016/j.str.2015.04.018] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2015] [Revised: 04/29/2015] [Accepted: 04/29/2015] [Indexed: 01/04/2023]
Abstract
Ski7 is a cofactor of the cytoplasmic exosome in budding yeast, functioning in both mRNA turnover and non-stop decay (NSD), a surveillance pathway that degrades faulty mRNAs lacking a stop codon. The C-terminal region of Ski7 (Ski7C) shares overall sequence similarity with the translational GTPase (trGTPase) Hbs1, but whether Ski7 has retained the properties of a trGTPase is unclear. Here, we report the high-resolution structures of Ski7C bound to either intact guanosine triphosphate (GTP) or guanosine diphosphate-Pi. The individual domains of Ski7C adopt the conformation characteristic of active trGTPases. Furthermore, the nucleotide-binding site of Ski7C shares similar features compared with active trGTPases, notably the presence of a characteristic monovalent cation. However, a suboptimal polar residue at the putative catalytic site and an unusual polar residue that interacts with the γ-phosphate of GTP distinguish Ski7 from other trGTPases, suggesting it might function rather as a GTP-binding protein than as a GTP-hydrolyzing enzyme.
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Affiliation(s)
- Eva Kowalinski
- Department of Structural Cell Biology Department, Max Planck Institute of Biochemistry, Am Klopferspitz 18, 82152 Martinsried, Germany
| | - Anthony Schuller
- Howard Hughes Medical Institute, Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Rachel Green
- Howard Hughes Medical Institute, Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Elena Conti
- Department of Structural Cell Biology Department, Max Planck Institute of Biochemistry, Am Klopferspitz 18, 82152 Martinsried, Germany.
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44
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The nuclear exosome is active and important during budding yeast meiosis. PLoS One 2014; 9:e107648. [PMID: 25210768 PMCID: PMC4161446 DOI: 10.1371/journal.pone.0107648] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2014] [Accepted: 08/18/2014] [Indexed: 11/19/2022] Open
Abstract
Nuclear RNA degradation pathways are highly conserved across eukaryotes and play important roles in RNA quality control. Key substrates for exosomal degradation include aberrant functional RNAs and cryptic unstable transcripts (CUTs). It has recently been reported that the nuclear exosome is inactivated during meiosis in budding yeast through degradation of the subunit Rrp6, leading to the stabilisation of a subset of meiotic unannotated transcripts (MUTs) of unknown function. We have analysed the activity of the nuclear exosome during meiosis by deletion of TRF4, which encodes a key component of the exosome targeting complex TRAMP. We find that TRAMP mutants produce high levels of CUTs during meiosis that are undetectable in wild-type cells, showing that the nuclear exosome remains functional for CUT degradation, and we further report that the meiotic exosome complex contains Rrp6. Indeed Rrp6 over-expression is insufficient to suppress MUT transcripts, showing that the reduced amount of Rrp6 in meiotic cells does not directly cause MUT accumulation. Lack of TRAMP activity stabilises ∼ 1600 CUTs in meiotic cells, which occupy 40% of the binding capacity of the nuclear cap binding complex (CBC). CBC mutants display defects in the formation of meiotic double strand breaks (DSBs), and we see similar defects in TRAMP mutants, suggesting that a key function of the nuclear exosome is to prevent saturation of the CBC complex by CUTs. Together, our results show that the nuclear exosome remains active in meiosis and has an important role in facilitating meiotic recombination.
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45
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Lykke-Andersen J, Bennett EJ. Protecting the proteome: Eukaryotic cotranslational quality control pathways. ACTA ACUST UNITED AC 2014; 204:467-76. [PMID: 24535822 PMCID: PMC3926952 DOI: 10.1083/jcb.201311103] [Citation(s) in RCA: 102] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The correct decoding of messenger RNAs (mRNAs) into proteins is an essential cellular task. The translational process is monitored by several quality control (QC) mechanisms that recognize defective translation complexes in which ribosomes are stalled on substrate mRNAs. Stalled translation complexes occur when defects in the mRNA template, the translation machinery, or the nascent polypeptide arrest the ribosome during translation elongation or termination. These QC events promote the disassembly of the stalled translation complex and the recycling and/or degradation of the individual mRNA, ribosomal, and/or nascent polypeptide components, thereby clearing the cell of improper translation products and defective components of the translation machinery.
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Affiliation(s)
- Jens Lykke-Andersen
- Division of Biological Sciences, University of California, San Diego, La Jolla, CA 92093
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46
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Lourenço RF, Leme AFP, Oliveira CC. Proteomic Analysis of Yeast Mutant RNA Exosome Complexes. J Proteome Res 2013; 12:5912-22. [DOI: 10.1021/pr400972x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Rogério F. Lourenço
- Department
of Biochemistry, Chemistry Institute, University of São Paulo, Av. Prof. Lineu Prestes 748, 05508-000 São Paulo, Brazil
| | - Adriana F. P. Leme
- Mass
Spectrometry Laboratory, Brazilian Biosciences National Laboratory- CNPEM, R. Giuseppe Máximo Scolfaro 10000, 13083-970 Campinas, Brazil
| | - Carla C. Oliveira
- Department
of Biochemistry, Chemistry Institute, University of São Paulo, Av. Prof. Lineu Prestes 748, 05508-000 São Paulo, Brazil
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47
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Halbach F, Reichelt P, Rode M, Conti E. The yeast ski complex: crystal structure and RNA channeling to the exosome complex. Cell 2013; 154:814-26. [PMID: 23953113 DOI: 10.1016/j.cell.2013.07.017] [Citation(s) in RCA: 128] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2012] [Revised: 05/13/2013] [Accepted: 07/12/2013] [Indexed: 10/26/2022]
Abstract
The Ski complex is a conserved multiprotein assembly required for the cytoplasmic functions of the exosome, including RNA turnover, surveillance, and interference. Ski2, Ski3, and Ski8 assemble in a tetramer with 1:1:2 stoichiometry. The crystal structure of an S. cerevisiae 370 kDa core complex shows that Ski3 forms an array of 33 TPR motifs organized in N-terminal and C-terminal arms. The C-terminal arm of Ski3 and the two Ski8 subunits position the helicase core of Ski2 centrally within the complex, enhancing RNA binding. The Ski3 N-terminal arm and the Ski2 insertion domain allosterically modulate the ATPase and helicase activities of the complex. Biochemical data suggest that the Ski complex can thread RNAs directly to the exosome, coupling the helicase and the exoribonuclease through a continuous RNA channel. Finally, we identify a Ski8-binding motif common to Ski3 and Spo11, rationalizing the moonlighting properties of Ski8 in mRNA decay and meiosis.
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Affiliation(s)
- Felix Halbach
- Department of Structural Cell Biology, Max Planck Institute of Biochemistry, Am Klopferspitz 18, 82152 Martinsried/Munich, Germany
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48
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Transfer RNA post-transcriptional processing, turnover, and subcellular dynamics in the yeast Saccharomyces cerevisiae. Genetics 2013; 194:43-67. [PMID: 23633143 DOI: 10.1534/genetics.112.147470] [Citation(s) in RCA: 145] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Transfer RNAs (tRNAs) are essential for protein synthesis. In eukaryotes, tRNA biosynthesis employs a specialized RNA polymerase that generates initial transcripts that must be subsequently altered via a multitude of post-transcriptional steps before the tRNAs beome mature molecules that function in protein synthesis. Genetic, genomic, biochemical, and cell biological approaches possible in the powerful Saccharomyces cerevisiae system have led to exciting advances in our understandings of tRNA post-transcriptional processing as well as to novel insights into tRNA turnover and tRNA subcellular dynamics. tRNA processing steps include removal of transcribed leader and trailer sequences, addition of CCA to the 3' mature sequence and, for tRNA(His), addition of a 5' G. About 20% of yeast tRNAs are encoded by intron-containing genes. The three-step splicing process to remove the introns surprisingly occurs in the cytoplasm in yeast and each of the splicing enzymes appears to moonlight in functions in addition to tRNA splicing. There are 25 different nucleoside modifications that are added post-transcriptionally, creating tRNAs in which ∼15% of the residues are nucleosides other than A, G, U, or C. These modified nucleosides serve numerous important functions including tRNA discrimination, translation fidelity, and tRNA quality control. Mature tRNAs are very stable, but nevertheless yeast cells possess multiple pathways to degrade inappropriately processed or folded tRNAs. Mature tRNAs are also dynamic in cells, moving from the cytoplasm to the nucleus and back again to the cytoplasm; the mechanism and function of this retrograde process is poorly understood. Here, the state of knowledge for tRNA post-transcriptional processing, turnover, and subcellular dynamics is addressed, highlighting the questions that remain.
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49
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Genomes of Ashbya fungi isolated from insects reveal four mating-type loci, numerous translocations, lack of transposons, and distinct gene duplications. G3-GENES GENOMES GENETICS 2013; 3:1225-39. [PMID: 23749448 PMCID: PMC3737163 DOI: 10.1534/g3.112.002881] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The filamentous fungus Ashbya gossypii is a cotton pathogen transmitted by insects. It is readily grown and manipulated in the laboratory and is commercially exploited as a natural overproducer of vitamin B2. Our previous genome analysis of A. gossypii isolate ATCC10895, collected in Trinidad nearly 100 years ago, revealed extensive synteny with the Saccharomyces cerevisiae genome, leading us to use it as a model organism to understand the evolution of filamentous growth. To further develop Ashbya as a model system, we have investigated the ecological niche of A. gossypii and isolated additional strains and a sibling species, both useful in comparative analysis. We isolated fungi morphologically similar to A. gossypii from different plant-feeding insects of the suborder Heteroptera, generated a phylogenetic tree based on rDNA-ITS sequences, and performed high coverage short read sequencing with one A. gossypii isolate from Florida, a new species, Ashbya aceri, isolated in North Carolina, and a genetically marked derivative of ATCC10895 intensively used for functional studies. In contrast to S. cerevisiae, all strains carry four not three mating type loci, adding a new puzzle in the evolution of Ashbya species. Another surprise was the genome identity of 99.9% between the Florida strain and ATCC10895, isolated in Trinidad. The A. aceri and A. gossypii genomes show conserved gene orders rearranged by eight translocations, 90% overall sequence identity, and fewer tandem duplications in the A. aceri genome. Both species lack transposable elements. Finally, our work identifies plant-feeding insects of the suborder Heteroptera as the most likely natural reservoir of Ashbya, and that infection of cotton and other plants may be incidental to the growth of the fungus in its insect host.
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50
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Alternative splicing and subfunctionalization generates functional diversity in fungal proteomes. PLoS Genet 2013; 9:e1003376. [PMID: 23516382 PMCID: PMC3597508 DOI: 10.1371/journal.pgen.1003376] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2012] [Accepted: 01/30/2013] [Indexed: 12/16/2022] Open
Abstract
Alternative splicing is commonly used by the Metazoa to generate more than one protein from a gene. However, such diversification of the proteome by alternative splicing is much rarer in fungi. We describe here an ancient fungal alternative splicing event in which these two proteins are generated from a single alternatively spliced ancestral SKI7/HBS1 gene retained in many species in both the Ascomycota and Basidiomycota. While the ability to express two proteins from a single SKI7/HBS1 gene is conserved in many fungi, the exact mechanism by which they achieve this varies. The alternative splicing was lost in Saccharomyces cerevisiae following the whole-genome duplication event as these two genes subfunctionalized into the present functionally distinct HBS1 and SKI7 genes. When expressed in yeast, the single gene from Lachancea kluyveri generates two functionally distinct proteins. Expression of one of these proteins complements hbs1, but not ski7 mutations, while the other protein complements ski7, but not hbs1. This is the first known case of subfunctionalization by loss of alternative splicing in yeast. By coincidence, the ancestral alternatively spliced gene was also duplicated in Schizosaccharomyces pombe with subsequent subfunctionalization and loss of splicing. Similar subfunctionalization by loss of alternative splicing in fungi also explains the presence of two PTC7 genes in the budding yeast Tetrapisispora blattae, suggesting that this is a common mechanism to preserve duplicate alternatively spliced genes. The role of duplicated genes in originating new functions is an important question in evolution. Almost all species have duplicated genes that carry out similar but not identical functions. Similar proteins that perform different functions can also be generated when one gene generates multiple mRNAs by alternative splicing that are translated into multiple similar proteins. This alternative splicing is prevalent in animal cells, but much rarer in fungi. Here we show that most fungi use alternative splicing to make a Ski7 protein and a Hbs1 protein from the same gene. Two fungi, budding yeast and fission yeast, have been much better characterized than other fungi, and co-incidentally they both have duplicated this alternatively spliced gene, resulting in two similar genes that are no longer alternatively spliced. Finally, we describe another example where two duplicate genes replace one alternatively spliced gene, suggesting that this is a common mechanism to divide functions among duplicate genes.
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