1
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Shen S, Zhang C, Meng Y, Cui G, Wang Y, Liu X, He Q. Sensing of H2O2-induced oxidative stress by the UPF factor complex is crucial for activation of catalase-3 expression in Neurospora. PLoS Genet 2023; 19:e1010985. [PMID: 37844074 PMCID: PMC10578600 DOI: 10.1371/journal.pgen.1010985] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2023] [Accepted: 09/19/2023] [Indexed: 10/18/2023] Open
Abstract
UPF-1-UPF-2-UPF-3 complex-orchestrated nonsense-mediated mRNA decay (NMD) is a well-characterized eukaryotic cellular surveillance mechanism that not only degrades aberrant transcripts to protect the integrity of the transcriptome but also eliminates normal transcripts to facilitate appropriate cellular responses to physiological and environmental changes. Here, we describe the multifaceted regulatory roles of the Neurospora crassa UPF complex in catalase-3 (cat-3) gene expression, which is essential for scavenging H2O2-induced oxidative stress. First, losing UPF proteins markedly slowed down the decay rate of cat-3 mRNA. Second, UPF proteins indirectly attenuated the transcriptional activity of cat-3 gene by boosting the decay of cpc-1 and ngf-1 mRNAs, which encode a well-studied transcription factor and a histone acetyltransferase, respectively. Further study showed that under oxidative stress condition, UPF proteins were degraded, followed by increased CPC-1 and NGF-1 activity, finally activating cat-3 expression to resist oxidative stress. Together, our data illustrate a sophisticated regulatory network of the cat-3 gene mediated by the UPF complex under physiological and H2O2-induced oxidative stress conditions.
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Affiliation(s)
- Shuangjie Shen
- MOA Key Laboratory of Soil Microbiology, College of Biological Sciences, China Agricultural University, Beijing, China
| | - Chengcheng Zhang
- MOA Key Laboratory of Soil Microbiology, College of Biological Sciences, China Agricultural University, Beijing, China
| | - Yuanhao Meng
- MOA Key Laboratory of Soil Microbiology, College of Biological Sciences, China Agricultural University, Beijing, China
| | - Guofei Cui
- MOA Key Laboratory of Soil Microbiology, College of Biological Sciences, China Agricultural University, Beijing, China
| | - Ying Wang
- MOA Key Laboratory of Soil Microbiology, College of Biological Sciences, China Agricultural University, Beijing, China
| | - Xiao Liu
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
- College of Life Sciences, University of the Chinese Academy of Sciences, Beijing, China
| | - Qun He
- MOA Key Laboratory of Soil Microbiology, College of Biological Sciences, China Agricultural University, Beijing, China
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2
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Chen X, Liu X, Gan X, Li S, Ma H, Zhang L, Wang P, Li Y, Huang T, Yang X, Fang L, Liang Y, Wu J, Chen T, Zhou Z, Liu X, Guo J. Differential regulation of phosphorylation, structure and stability of circadian clock protein FRQ isoforms. J Biol Chem 2023; 299:104597. [PMID: 36898580 PMCID: PMC10140173 DOI: 10.1016/j.jbc.2023.104597] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2022] [Revised: 01/20/2023] [Accepted: 01/23/2023] [Indexed: 03/12/2023] Open
Abstract
Neurospora crassa is an important model for circadian clock research. The Neurospora core circadian component FRQ protein has two isoforms, large FRQ (l-FRQ) and small FRQ (s-FRQ), of which l-FRQ bears an additional N-terminal 99-amino acid fragment. However, how the FRQ isoforms operate differentially in regulating the circadian clock remains elusive. Here, we show l-FRQ and s-FRQ play different roles in regulating the circadian negative feedback loop. Compared to s-FRQ, l-FRQ is less stable at three temperatures, and undergoes hypophosphorylation and faster degradation. The phosphorylation of the C-terminal l-FRQ 794-aa fragment was markedly higher than that of s-FRQ, suggesting the l-FRQ N-terminal 99-aa region may regulate phosphorylation of the entire FRQ protein. Quantitative label-free LC/MS analysis identified several peptides that were differentially phosphorylated between l-FRQ and s-FRQ, which were distributed in FRQ in an interlaced fashion. Furthermore, we identified two novel phosphorylation sites, S765 and T781; mutations S765A and T781A showed no significant effects on conidiation rhythmicity, although T781 conferred FRQ stability. These findings demonstrate that FRQ isoforms play differential roles in the circadian negative feedback loop and undergo different regulation of phosphorylation, structure, and stability. The l-FRQ N-terminal 99-aa region plays an important role in regulating the phosphorylation, stability, conformation, and function of the FRQ protein. As the FRQ circadian clock counterparts in other species also have isoforms or paralogues, these findings will also further our understanding of the underlying regulatory mechanisms of the circadian clock in other organisms based on the high conservation of circadian clocks in eukaryotes.
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Affiliation(s)
- Xianyun Chen
- State Key Laboratory of Biocontrol, Key Laboratory of Gene Engineering of the Ministry of Education, School of Life Sciences, Sun Yat-sen University, Guangzhou 510006, China
| | - Xiaolan Liu
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China
| | - Xihui Gan
- State Key Laboratory of Biocontrol, Key Laboratory of Gene Engineering of the Ministry of Education, School of Life Sciences, Sun Yat-sen University, Guangzhou 510006, China
| | - Silin Li
- State Key Laboratory of Biocontrol, Key Laboratory of Gene Engineering of the Ministry of Education, School of Life Sciences, Sun Yat-sen University, Guangzhou 510006, China
| | - Huan Ma
- State Key Laboratory of Biocontrol, Key Laboratory of Gene Engineering of the Ministry of Education, School of Life Sciences, Sun Yat-sen University, Guangzhou 510006, China
| | - Lin Zhang
- State Key Laboratory of Biocontrol, Key Laboratory of Gene Engineering of the Ministry of Education, School of Life Sciences, Sun Yat-sen University, Guangzhou 510006, China
| | - Peiliang Wang
- State Key Laboratory of Biocontrol, Key Laboratory of Gene Engineering of the Ministry of Education, School of Life Sciences, Sun Yat-sen University, Guangzhou 510006, China
| | - Yunzhen Li
- State Key Laboratory of Biocontrol, Key Laboratory of Gene Engineering of the Ministry of Education, School of Life Sciences, Sun Yat-sen University, Guangzhou 510006, China
| | - Tianyu Huang
- State Key Laboratory of Biocontrol, Key Laboratory of Gene Engineering of the Ministry of Education, School of Life Sciences, Sun Yat-sen University, Guangzhou 510006, China
| | - Xiaolin Yang
- State Key Laboratory of Biocontrol, Key Laboratory of Gene Engineering of the Ministry of Education, School of Life Sciences, Sun Yat-sen University, Guangzhou 510006, China
| | - Ling Fang
- Sun Yat-sen University Instrumental Analysis & Research Center, Sun Yat-sen University, Guangzhou 510006, China
| | - Yingying Liang
- State Key Laboratory of Biocontrol, Key Laboratory of Gene Engineering of the Ministry of Education, School of Life Sciences, Sun Yat-sen University, Guangzhou 510006, China
| | - Jingjing Wu
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China
| | - Tongyue Chen
- State Key Laboratory of Biocontrol, Key Laboratory of Gene Engineering of the Ministry of Education, School of Life Sciences, Sun Yat-sen University, Guangzhou 510006, China
| | - Zengxuan Zhou
- State Key Laboratory of Biocontrol, Key Laboratory of Gene Engineering of the Ministry of Education, School of Life Sciences, Sun Yat-sen University, Guangzhou 510006, China
| | - Xiao Liu
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China
| | - Jinhu Guo
- State Key Laboratory of Biocontrol, Key Laboratory of Gene Engineering of the Ministry of Education, School of Life Sciences, Sun Yat-sen University, Guangzhou 510006, China.
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3
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Katsioudi G, Dreos R, Arpa ES, Gaspari S, Liechti A, Sato M, Gabriel CH, Kramer A, Brown SA, Gatfield D. A conditional Smg6 mutant mouse model reveals circadian clock regulation through the nonsense-mediated mRNA decay pathway. SCIENCE ADVANCES 2023; 9:eade2828. [PMID: 36638184 PMCID: PMC9839329 DOI: 10.1126/sciadv.ade2828] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/05/2022] [Accepted: 12/15/2022] [Indexed: 06/17/2023]
Abstract
Nonsense-mediated messenger RNA (mRNA) decay (NMD) has been intensively studied as a surveillance pathway that degrades erroneous transcripts arising from mutations or RNA processing errors. While additional roles in physiological control of mRNA stability have emerged, possible functions in mammalian physiology in vivo remain unclear. Here, we created a conditional mouse allele that allows converting the NMD effector nuclease SMG6 from wild-type to nuclease domain-mutant protein. We find that NMD down-regulation affects the function of the circadian clock, a system known to require rapid mRNA turnover. Specifically, we uncover strong lengthening of free-running circadian periods for liver and fibroblast clocks and direct NMD regulation of Cry2 mRNA, encoding a key transcriptional repressor within the rhythm-generating feedback loop. Transcriptome-wide changes in daily mRNA accumulation patterns in the entrained liver, as well as an altered response to food entrainment, expand the known scope of NMD regulation in mammalian gene expression and physiology.
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Affiliation(s)
- Georgia Katsioudi
- Center for Integrative Genomics, University of Lausanne, Lausanne, Switzerland
| | - René Dreos
- Center for Integrative Genomics, University of Lausanne, Lausanne, Switzerland
| | - Enes S. Arpa
- Center for Integrative Genomics, University of Lausanne, Lausanne, Switzerland
| | - Sevasti Gaspari
- Center for Integrative Genomics, University of Lausanne, Lausanne, Switzerland
| | - Angelica Liechti
- Center for Integrative Genomics, University of Lausanne, Lausanne, Switzerland
| | - Miho Sato
- Chronobiology and Sleep Research Group, Institute of Pharmacology and Toxicology, University of Zürich, Zürich, Switzerland
| | - Christian H. Gabriel
- Charité Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Laboratory of Chronobiology, Berlin, Germany
| | - Achim Kramer
- Charité Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Laboratory of Chronobiology, Berlin, Germany
| | - Steven A. Brown
- Chronobiology and Sleep Research Group, Institute of Pharmacology and Toxicology, University of Zürich, Zürich, Switzerland
| | - David Gatfield
- Center for Integrative Genomics, University of Lausanne, Lausanne, Switzerland
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4
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Kelliher CM, Stevenson EL, Loros JJ, Dunlap JC. Nutritional compensation of the circadian clock is a conserved process influenced by gene expression regulation and mRNA stability. PLoS Biol 2023; 21:e3001961. [PMID: 36603054 PMCID: PMC9848017 DOI: 10.1371/journal.pbio.3001961] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Revised: 01/18/2023] [Accepted: 12/15/2022] [Indexed: 01/06/2023] Open
Abstract
Compensation is a defining principle of a true circadian clock, where its approximately 24-hour period length is relatively unchanged across environmental conditions. Known compensation effectors directly regulate core clock factors to buffer the oscillator's period length from variables in the environment. Temperature Compensation mechanisms have been experimentally addressed across circadian model systems, but much less is known about the related process of Nutritional Compensation, where circadian period length is maintained across physiologically relevant nutrient levels. Using the filamentous fungus Neurospora crassa, we performed a genetic screen under glucose and amino acid starvation conditions to identify new regulators of Nutritional Compensation. Our screen uncovered 16 novel mutants, and together with 4 mutants characterized in prior work, a model emerges where Nutritional Compensation of the fungal clock is achieved at the levels of transcription, chromatin regulation, and mRNA stability. However, eukaryotic circadian Nutritional Compensation is completely unstudied outside of Neurospora. To test for conservation in cultured human cells, we selected top hits from our fungal genetic screen, performed siRNA knockdown experiments of the mammalian orthologs, and characterized the cell lines with respect to compensation. We find that the wild-type mammalian clock is also compensated across a large range of external glucose concentrations, as observed in Neurospora, and that knocking down the mammalian orthologs of the Neurospora compensation-associated genes CPSF6 or SETD2 in human cells also results in nutrient-dependent period length changes. We conclude that, like Temperature Compensation, Nutritional Compensation is a conserved circadian process in fungal and mammalian clocks and that it may share common molecular determinants.
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Affiliation(s)
- Christina M. Kelliher
- Department of Molecular & Systems Biology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, United States of America
- Department of Biology, University of Massachusetts Boston, Boston, Massachusetts, United States of America
| | - Elizabeth-Lauren Stevenson
- Department of Molecular & Systems Biology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, United States of America
| | - Jennifer J. Loros
- Department of Biochemistry & Cell Biology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, United States of America
| | - Jay C. Dunlap
- Department of Molecular & Systems Biology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, United States of America
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5
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The Resonance and Adaptation of Neurospora crassa Circadian and Conidiation Rhyth ms to Short Light-Dark Cycles. J Fungi (Basel) 2021; 8:jof8010027. [PMID: 35049967 PMCID: PMC8780863 DOI: 10.3390/jof8010027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2021] [Revised: 12/21/2021] [Accepted: 12/25/2021] [Indexed: 11/17/2022] Open
Abstract
Circadian clocks control the physiological and behavioral rhythms to adapt to the environment with a period of ~24 h. However, the influences and mechanisms of the extreme light/dark cycles on the circadian clock remain unclear. We showed that, in Neurospora crassa, both the growth and the microconidia production contribute to adaptation in LD12:12 (12 h light/12 h dark, periodically). Mathematical modeling and experiments demonstrate that in short LD cycles, the expression of the core clock protein FREQUENCY was entrained to the LD cycles when LD > 3:3 while it free ran when T ≤ LD3:3. The conidial rhythmicity can resonate with a series of different LD conditions. Moreover, we demonstrate that the existence of unknown blue light photoreceptor(s) and the circadian clock might promote the conidiation rhythms that resonate with the environment. The ubiquitin E3 ligase FWD-1 and the previously described CRY-dependent oscillator system were implicated in regulating conidiation under short LD conditions. These findings shed new light on the resonance of Neurospora circadian clock and conidiation rhythms to short LD cycles, which may benefit the understandings of both the basic regulatory aspects of circadian clock and the adaptation of physiological rhythms to the extreme conditions.
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6
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Kelliher CM, Lambreghts R, Xiang Q, Baker CL, Loros JJ, Dunlap JC. PRD-2 directly regulates casein kinase I and counteracts nonsense-mediated decay in the Neurospora circadian clock. eLife 2020; 9:64007. [PMID: 33295874 PMCID: PMC7746235 DOI: 10.7554/elife.64007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2020] [Accepted: 12/08/2020] [Indexed: 01/22/2023] Open
Abstract
Circadian clocks in fungi and animals are driven by a functionally conserved transcription–translation feedback loop. In Neurospora crassa, negative feedback is executed by a complex of Frequency (FRQ), FRQ-interacting RNA helicase (FRH), and casein kinase I (CKI), which inhibits the activity of the clock’s positive arm, the White Collar Complex (WCC). Here, we show that the prd-2 (period-2) gene, whose mutation is characterized by recessive inheritance of a long 26 hr period phenotype, encodes an RNA-binding protein that stabilizes the ck-1a transcript, resulting in CKI protein levels sufficient for normal rhythmicity. Moreover, by examining the molecular basis for the short circadian period of upf-1prd-6 mutants, we uncovered a strong influence of the Nonsense-Mediated Decay pathway on CKI levels. The finding that circadian period defects in two classically derived Neurospora clock mutants each arise from disruption of ck-1a regulation is consistent with circadian period being exquisitely sensitive to levels of casein kinase I.
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Affiliation(s)
- Christina M Kelliher
- Department of Molecular & Systems Biology, Geisel School of Medicine at Dartmouth, Hanover, United States
| | - Randy Lambreghts
- Department of Molecular & Systems Biology, Geisel School of Medicine at Dartmouth, Hanover, United States
| | - Qijun Xiang
- Department of Molecular & Systems Biology, Geisel School of Medicine at Dartmouth, Hanover, United States
| | - Christopher L Baker
- Department of Molecular & Systems Biology, Geisel School of Medicine at Dartmouth, Hanover, United States.,The Jackson Laboratory, Bar Harbor, United States
| | - Jennifer J Loros
- Department of Biochemistry & Cell Biology, Geisel School of Medicine at Dartmouth, Hanover, United States
| | - Jay C Dunlap
- Department of Molecular & Systems Biology, Geisel School of Medicine at Dartmouth, Hanover, United States
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7
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Neumann A, Meinke S, Goldammer G, Strauch M, Schubert D, Timmermann B, Heyd F, Preußner M. Alternative splicing coupled mRNA decay shapes the temperature-dependent transcriptome. EMBO Rep 2020; 21:e51369. [PMID: 33140569 PMCID: PMC7726792 DOI: 10.15252/embr.202051369] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Revised: 10/02/2020] [Accepted: 10/08/2020] [Indexed: 11/09/2022] Open
Abstract
Mammalian body temperature oscillates with the time of the day and is altered in diverse pathological conditions. We recently identified a body temperature‐sensitive thermometer‐like kinase, which alters SR protein phosphorylation and thereby globally controls alternative splicing (AS). AS can generate unproductive variants which are recognized and degraded by diverse mRNA decay pathways—including nonsense‐mediated decay (NMD). Here we show extensive coupling of body temperature‐controlled AS to mRNA decay, leading to global control of temperature‐dependent gene expression (GE). Temperature‐controlled, decay‐inducing splicing events are evolutionarily conserved and pervasively found within RNA‐binding proteins, including most SR proteins. AS‐coupled poison exon inclusion is essential for rhythmic GE of SR proteins and has a global role in establishing temperature‐dependent rhythmic GE profiles, both in mammals under circadian body temperature cycles and in plants in response to ambient temperature changes. Together, these data identify body temperature‐driven AS‐coupled mRNA decay as an evolutionary ancient, core clock‐independent mechanism to generate rhythmic GE.
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Affiliation(s)
- Alexander Neumann
- Institute of Chemistry and Biochemistry, Laboratory of RNA Biochemistry, Freie Universität Berlin, Berlin, Germany.,Omiqa Bioinformatics, Berlin, Germany
| | - Stefan Meinke
- Institute of Chemistry and Biochemistry, Laboratory of RNA Biochemistry, Freie Universität Berlin, Berlin, Germany
| | - Gesine Goldammer
- Institute of Chemistry and Biochemistry, Laboratory of RNA Biochemistry, Freie Universität Berlin, Berlin, Germany
| | - Miriam Strauch
- Institute of Chemistry and Biochemistry, Laboratory of RNA Biochemistry, Freie Universität Berlin, Berlin, Germany
| | - Daniel Schubert
- Epigenetics of Plants, Freie Universität Berlin, Berlin, Germany
| | - Bernd Timmermann
- Sequencing Core Facility, Max-Planck-Institute for Molecular Genetics, Berlin, Germany
| | - Florian Heyd
- Institute of Chemistry and Biochemistry, Laboratory of RNA Biochemistry, Freie Universität Berlin, Berlin, Germany
| | - Marco Preußner
- Institute of Chemistry and Biochemistry, Laboratory of RNA Biochemistry, Freie Universität Berlin, Berlin, Germany
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8
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Kurilla A, Szőke A, Auber A, Káldi K, Silhavy D. Expression of the translation termination factor eRF1 is autoregulated by translational readthrough and 3'UTR intron-mediated NMD in Neurospora crassa. FEBS Lett 2020; 594:3504-3517. [PMID: 32869294 DOI: 10.1002/1873-3468.13918] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2020] [Revised: 07/30/2020] [Accepted: 08/17/2020] [Indexed: 01/24/2023]
Abstract
Eukaryotic release factor 1 (eRF1) is a translation termination factor that binds to the ribosome at stop codons. The expression of eRF1 is strictly controlled, since its concentration defines termination efficiency and frequency of translational readthrough. Here, we show that eRF1 expression in Neurospora crassa is controlled by an autoregulatory circuit that depends on the specific 3'UTR structure of erf1 mRNA. The stop codon context of erf1 promotes readthrough that protects the mRNA from its 3'UTR-induced nonsense-mediated mRNA decay (NMD). High eRF1 concentration leads to inefficient readthrough, thereby allowing NMD-mediated erf1 degradation. We propose that eRF1 expression is controlled by similar autoregulatory circuits in many fungi and seed plants and discuss the evolution of autoregulatory systems of different translation termination factors.
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Affiliation(s)
- Anita Kurilla
- Department of Genetics, NARIC, Agricultural Biotechnology Institute, Gödöllő, Hungary
| | - Anita Szőke
- Department of Physiology, Faculty of Medicine, Semmelweis University, Budapest, Hungary
| | - Andor Auber
- Department of Genetics, NARIC, Agricultural Biotechnology Institute, Gödöllő, Hungary
| | - Krisztina Káldi
- Department of Physiology, Faculty of Medicine, Semmelweis University, Budapest, Hungary
| | - Dániel Silhavy
- Department of Genetics, NARIC, Agricultural Biotechnology Institute, Gödöllő, Hungary.,Biological Research Centre, Institute of Plant Biology, Szeged, Hungary
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9
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Regulation of the Neurospora Circadian Clock by the Spliceosome Component PRP5. G3-GENES GENOMES GENETICS 2019; 9:3653-3661. [PMID: 31511298 PMCID: PMC6829141 DOI: 10.1534/g3.119.400500] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Increasing evidence has pointed to the connection between pre-mRNA splicing and the circadian clock; however, the underlying mechanisms of this connection remain largely elusive. In the filamentous fungus Neurospora crassa, the core circadian clock elements comprise White Collar 1 (WC-1), WC-2 and FREQUENCY (FRQ), which form a negative feedback loop to control the circadian rhythms of gene expression and physiological processes. Previously, we have shown that in Neurospora, the pre-mRNA splicing factors Pre-mRNA-processing ATP-dependent RNA helicase 5 (PRP5), protein arginine methyl transferase 5 (PRMT5) and snRNA gene U4-2 are involved in the regulation of splicing of frq transcripts, which encode the negative component of the circadian clock system. In this work we further demonstrated that repression of spliceosomal component sRNA genes, U5, U4-1, and prp5, affected the circadian conidiation rhythms. In a prp5 knockdown strain, the molecular rhythmicity was dampened. The expression of a set of snRNP genes including prp5 was up-regulated in a mutant strain lacking the clock component wc-2, suggesting that the function of spliceosome might be under the circadian control. Among these snRNP genes, the levels of prp5 RNA and PRP5 protein oscillated. The distribution of PRP5 in cytosol was rhythmic, suggesting a dynamic assembly of PRP5 in the spliceosome complex in a circadian fashion. Silencing of prp5 caused changes in the transcription and splicing of NCU09649, a clock-controlled gene. Moreover, in the clock mutant frq9, the rhythmicity of frq I-6 splicing was abolished. These data shed new lights on the regulation of circadian clock by the pre-RNA splicing, and PRP5 may link the circadian clock and pre-RNA splicing events through mediating the assembly and function of the spliceosome complex.
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10
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Ri H, Lee J, Sonn JY, Yoo E, Lim C, Choe J. Drosophila CrebB is a Substrate of the Nonsense-Mediated mRNA Decay Pathway that Sustains Circadian Behaviors. Mol Cells 2019; 42:301-312. [PMID: 31091556 PMCID: PMC6530642 DOI: 10.14348/molcells.2019.2451] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2018] [Revised: 01/21/2019] [Accepted: 01/21/2019] [Indexed: 12/23/2022] Open
Abstract
Post-transcriptional regulation underlies the circadian control of gene expression and animal behaviors. However, the role of mRNA surveillance via the nonsense-mediated mRNA decay (NMD) pathway in circadian rhythms remains elusive. Here, we report that Drosophila NMD pathway acts in a subset of circadian pacemaker neurons to maintain robust 24 h rhythms of free-running locomotor activity. RNA interference-mediated depletion of key NMD factors in timeless-expressing clock cells decreased the amplitude of circadian locomotor behaviors. Transgenic manipulation of the NMD pathway in clock neurons expressing a neuropeptide PIGMENT-DISPERSING FACTOR (PDF) was sufficient to dampen or lengthen free-running locomotor rhythms. Confocal imaging of a transgenic NMD reporter revealed that arrhythmic Clock mutants exhibited stronger NMD activity in PDF-expressing neurons than wild-type. We further found that hypomorphic mutations in Suppressor with morphogenetic effect on genitalia 5 (Smg5 ) or Smg6 impaired circadian behaviors. These NMD mutants normally developed PDF-expressing clock neurons and displayed daily oscillations in the transcript levels of core clock genes. By contrast, the loss of Smg5 or Smg6 function affected the relative transcript levels of cAMP response element-binding protein B (CrebB ) in an isoform-specific manner. Moreover, the overexpression of a transcriptional repressor form of CrebB rescued free-running locomotor rhythms in Smg5-depleted flies. These data demonstrate that CrebB is a rate-limiting substrate of the genetic NMD pathway important for the behavioral output of circadian clocks in Drosophila.
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Affiliation(s)
- Hwajung Ri
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141,
Korea
| | - Jongbin Lee
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141,
Korea
| | - Jun Young Sonn
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141,
Korea
| | - Eunseok Yoo
- School of Life Sciences, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919,
Korea
| | - Chunghun Lim
- School of Life Sciences, Ulsan National Institute of Science and Technology (UNIST), Ulsan 44919,
Korea
| | - Joonho Choe
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141,
Korea
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11
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Beyond Transcription: Fine-Tuning of Circadian Timekeeping by Post-Transcriptional Regulation. Genes (Basel) 2018; 9:genes9120616. [PMID: 30544736 PMCID: PMC6315869 DOI: 10.3390/genes9120616] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2018] [Revised: 11/29/2018] [Accepted: 12/03/2018] [Indexed: 12/28/2022] Open
Abstract
The circadian clock is an important endogenous timekeeper, helping plants to prepare for the periodic changes of light and darkness in their environment. The clockwork of this molecular timer is made up of clock proteins that regulate transcription of their own genes with a 24 h rhythm. Furthermore, the rhythmically expressed clock proteins regulate time-of-day dependent transcription of downstream genes, causing messenger RNA (mRNA) oscillations of a large part of the transcriptome. On top of the transcriptional regulation by the clock, circadian rhythms in mRNAs rely in large parts on post-transcriptional regulation, including alternative pre-mRNA splicing, mRNA degradation, and translational control. Here, we present recent insights into the contribution of post-transcriptional regulation to core clock function and to regulation of circadian gene expression in Arabidopsis thaliana.
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