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Carlier F, Castro Ramirez S, Kilani J, Chehboub S, Loïodice I, Taddei A, Gladyshev E. Remodeling of perturbed chromatin can initiate de novo transcriptional and post-transcriptional silencing. Proc Natl Acad Sci U S A 2024; 121:e2402944121. [PMID: 39052837 PMCID: PMC11295056 DOI: 10.1073/pnas.2402944121] [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: 02/20/2024] [Accepted: 06/17/2024] [Indexed: 07/27/2024] Open
Abstract
In eukaryotes, repetitive DNA can become silenced de novo, either transcriptionally or post-transcriptionally, by processes independent of strong sequence-specific cues. The mechanistic nature of such processes remains poorly understood. We found that in the fungus Neurospora crassa, de novo initiation of both transcriptional and post-transcriptional silencing was linked to perturbed chromatin, which was produced experimentally by the aberrant activity of transcription factors at the tetO operator array. Transcriptional silencing was mediated by canonical constitutive heterochromatin. On the other hand, post-transcriptional silencing resembled repeat-induced quelling but occurred normally when homologous recombination was inactivated. All silencing of the tetO array was dependent on SAD-6, fungal ortholog of the SWI/SNF chromatin remodeler ATRX (Alpha Thalassemia/Mental Retardation Syndrome X-Linked), which was required to maintain nucleosome occupancy at the perturbed locus. In addition, we found that two other types of sequences (the lacO array and native AT-rich DNA) could also undergo recombination-independent quelling associated with perturbed chromatin. These results suggested a model in which the de novo initiation of transcriptional and post-transcriptional silencing is coupled to the remodeling of perturbed chromatin.
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Affiliation(s)
- Florian Carlier
- Institut Pasteur, Department of Mycology, Molecular Genetics and Epigenetics Unit, Université Paris Cité, Paris75015, France
| | - Sebastian Castro Ramirez
- Institut Pasteur, Department of Mycology, Molecular Genetics and Epigenetics Unit, Université Paris Cité, Paris75015, France
| | - Jaafar Kilani
- Institut Pasteur, Department of Mycology, Molecular Genetics and Epigenetics Unit, Université Paris Cité, Paris75015, France
| | - Sara Chehboub
- Institut Pasteur, Department of Mycology, Molecular Genetics and Epigenetics Unit, Université Paris Cité, Paris75015, France
| | - Isabelle Loïodice
- Institut Curie, UMR3664 Nuclear Dynamics, CNRS, Université Paris Sciences et Lettres, Sorbonne Université, Paris75005, France
| | - Angela Taddei
- Institut Curie, UMR3664 Nuclear Dynamics, CNRS, Université Paris Sciences et Lettres, Sorbonne Université, Paris75005, France
| | - Eugene Gladyshev
- Institut Pasteur, Department of Mycology, Molecular Genetics and Epigenetics Unit, Université Paris Cité, Paris75015, France
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Liu XL, Duan Z, Yu M, Liu X. Epigenetic control of circadian clocks by environmental signals. Trends Cell Biol 2024:S0962-8924(24)00028-X. [PMID: 38423855 DOI: 10.1016/j.tcb.2024.02.005] [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: 12/14/2023] [Revised: 02/01/2024] [Accepted: 02/05/2024] [Indexed: 03/02/2024]
Abstract
Circadian clocks have evolved to enable organisms to respond to daily environmental changes. Maintaining a robust circadian rhythm under various perturbations and stresses is essential for the fitness of an organism. In the core circadian oscillator conserved in eukaryotes (from fungi to mammals), a negative feedback loop based on both transcription and translation drives circadian rhythms. The expression of circadian clock genes depends both on the binding of transcription activators at the promoter and on the chromatin state of the clock genes, and epigenetic modifications of chromatin are crucial for transcriptional regulation of circadian clock genes. Herein we review current knowledge of epigenetic regulation of circadian clock mechanisms and discuss how environmental cues can control clock gene expression by affecting chromatin states.
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Affiliation(s)
- Xiao-Lan Liu
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China
| | - Zeyu Duan
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China
| | - Muqun Yu
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China
| | - Xiao Liu
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, 100101, China; College of Life Sciences, University of the Chinese Academy of Sciences, Beijing, 100049, China.
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3
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Bayram ÖS, Bayram Ö. An Anatomy of Fungal Eye: Fungal Photoreceptors and Signalling Mechanisms. J Fungi (Basel) 2023; 9:jof9050591. [PMID: 37233302 DOI: 10.3390/jof9050591] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2023] [Revised: 05/08/2023] [Accepted: 05/15/2023] [Indexed: 05/27/2023] Open
Abstract
Organisms have developed different features to capture or sense sunlight. Vertebrates have evolved specialized organs (eyes) which contain a variety of photosensor cells that help them to see the light to aid orientation. Opsins are major photoreceptors found in the vertebrate eye. Fungi, with more than five million estimated members, represent an important clade of living organisms which have important functions for the sustainability of life on our planet. Light signalling regulates a range of developmental and metabolic processes including asexual sporulation, sexual fruit body formation, pigment and carotenoid production and even production of secondary metabolites. Fungi have adopted three groups of photoreceptors: (I) blue light receptors, White Collars, vivid, cryptochromes, blue F proteins and DNA photolyases, (II) red light sensors, phytochromes and (III) green light sensors and microbial rhodopsins. Most mechanistic data were elucidated on the roles of the White Collar Complex (WCC) and the phytochromes in the fungal kingdom. The WCC acts as both photoreceptor and transcription factor by binding to target genes, whereas the phytochrome initiates a cascade of signalling by using mitogen-activated protein kinases to elicit its cellular responses. Although the mechanism of photoreception has been studied in great detail, fungal photoreception has not been compared with vertebrate vision. Therefore, this review will mainly focus on mechanistic findings derived from two model organisms, namely Aspergillus nidulans and Neurospora crassa and comparison of some mechanisms with vertebrate vision. Our focus will be on the way light signalling is translated into changes in gene expression, which influences morphogenesis and metabolism in fungi.
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Affiliation(s)
| | - Özgür Bayram
- Biology Department, Maynooth University, W23 F2K8 Maynooth, Co. Kildare, Ireland
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Pelham JF, Mosier AE, Altshuler SC, Rhodes ML, Kirchhoff CL, Fall WB, Mann C, Baik LS, Chiu JC, Hurley JM. Conformational changes in the negative arm of the circadian clock correlate with dynamic interactomes involved in post-transcriptional regulation. Cell Rep 2023; 42:112376. [PMID: 37043358 PMCID: PMC10562519 DOI: 10.1016/j.celrep.2023.112376] [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: 12/07/2021] [Revised: 09/16/2022] [Accepted: 03/24/2023] [Indexed: 04/13/2023] Open
Abstract
Biology is tuned to the Earth's diurnal cycle by the circadian clock, a transcriptional/translational negative feedback loop that regulates physiology via transcriptional activation and other post-transcriptional mechanisms. We hypothesize that circadian post-transcriptional regulation might stem from conformational shifts in the intrinsically disordered proteins that comprise the negative arm of the feedback loop to coordinate variation in negative-arm-centered macromolecular complexes. This work demonstrates temporal conformational fluidity in the negative arm that correlates with 24-h variation in physiologically diverse macromolecular complex components in eukaryotic clock proteins. Short linear motifs on the negative-arm proteins that correspond with the interactors localized to disordered regions and known temporal phosphorylation sites suggesting changes in these macromolecular complexes could be due to conformational changes imparted by the temporal phospho-state. Interactors that oscillate in the macromolecular complexes over circadian time correlate with post-transcriptionally regulated proteins, highlighting how time-of-day variation in the negative-arm protein complexes may tune cellular physiology.
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Affiliation(s)
- Jacqueline F Pelham
- Department of Biological Sciences, Rensselaer Polytechnic Institute, Troy, NY 12180, USA
| | - Alexander E Mosier
- Department of Biological Sciences, Rensselaer Polytechnic Institute, Troy, NY 12180, USA
| | - Samuel C Altshuler
- Department of Biological Sciences, Rensselaer Polytechnic Institute, Troy, NY 12180, USA
| | - Morgan L Rhodes
- Department of Biological Sciences, Rensselaer Polytechnic Institute, Troy, NY 12180, USA
| | | | - William B Fall
- Department of Biological Sciences, Rensselaer Polytechnic Institute, Troy, NY 12180, USA
| | - Catherine Mann
- Department of Biological Sciences, Rensselaer Polytechnic Institute, Troy, NY 12180, USA
| | - Lisa S Baik
- Department of Entomology and Nematology, University of California, Davis, Davis, CA 95616, USA
| | - Joanna C Chiu
- Department of Entomology and Nematology, University of California, Davis, Davis, CA 95616, USA
| | - Jennifer M Hurley
- Department of Biological Sciences, Rensselaer Polytechnic Institute, Troy, NY 12180, USA; Center for Biotechnology and Interdisciplinary Sciences, Rensselaer Polytechnic Institute, Troy, NY 12180, USA.
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Rodriguez S, Ward A, Reckard AT, Shtanko Y, Hull-Crew C, Klocko AD. The genome organization of Neurospora crassa at high resolution uncovers principles of fungal chromosome topology. G3 (BETHESDA, MD.) 2022; 12:jkac053. [PMID: 35244156 PMCID: PMC9073679 DOI: 10.1093/g3journal/jkac053] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Accepted: 02/25/2022] [Indexed: 01/17/2023]
Abstract
The eukaryotic genome must be precisely organized for its proper function, as genome topology impacts transcriptional regulation, cell division, replication, and repair, among other essential processes. Disruptions to human genome topology can lead to diseases, including cancer. The advent of chromosome conformation capture with high-throughput sequencing (Hi-C) to assess genome organization has revolutionized the study of nuclear genome topology; Hi-C has elucidated numerous genomic structures, including chromosomal territories, active/silent chromatin compartments, Topologically Associated Domains, and chromatin loops. While low-resolution heatmaps can provide important insights into chromosomal level contacts, high-resolution Hi-C datasets are required to reveal folding principles of individual genes. Of particular interest are high-resolution chromosome conformation datasets of organisms modeling the human genome. Here, we report the genome topology of the fungal model organism Neurospora crassa at a high resolution. Our composite Hi-C dataset, which merges 2 independent datasets generated with restriction enzymes that monitor euchromatin (DpnII) and heterochromatin (MseI), along with our DpnII/MseI double digest dataset, provide exquisite detail for both the conformation of entire chromosomes and the folding of chromatin at the resolution of individual genes. Within constitutive heterochromatin, we observe strong yet stochastic internal contacts, while euchromatin enriched with either activating or repressive histone post-translational modifications associates with constitutive heterochromatic regions, suggesting intercompartment contacts form to regulate transcription. Consistent with this, a strain with compromised heterochromatin experiences numerous changes in gene expression. Our high-resolution Neurospora Hi-C datasets are outstanding resources to the fungal community and provide valuable insights into higher organism genome topology.
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Affiliation(s)
- Sara Rodriguez
- Department of Chemistry & Biochemistry, University of Colorado Colorado Springs, Colorado Springs, CO 80918, USA
| | - Ashley Ward
- Department of Chemistry & Biochemistry, University of Colorado Colorado Springs, Colorado Springs, CO 80918, USA
| | - Andrew T Reckard
- Department of Chemistry & Biochemistry, University of Colorado Colorado Springs, Colorado Springs, CO 80918, USA
| | - Yulia Shtanko
- Department of Chemistry & Biochemistry, University of Colorado Colorado Springs, Colorado Springs, CO 80918, USA
| | - Clayton Hull-Crew
- Department of Chemistry & Biochemistry, University of Colorado Colorado Springs, Colorado Springs, CO 80918, USA
| | - Andrew D Klocko
- Department of Chemistry & Biochemistry, University of Colorado Colorado Springs, Colorado Springs, CO 80918, USA
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Ren K, Mou YN, Tong SM, Ying SH, Feng MG. DIM5/KMT1 controls fungal insect pathogenicity and genome stability by methylation of histone H3K4, H3K9 and H3K36. Virulence 2021; 12:1306-1322. [PMID: 33955325 PMCID: PMC8115510 DOI: 10.1080/21505594.2021.1923232] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Mono-, di- and tri-methylation of histone H3 Lys 9, Lys 4, and Lys 36 (H3K_me1/me2/me3) required for mediation of DNA-based cellular events in eukaryotes usually rely upon the activities of histone lysine methyltransferases (KMTs) classified to the KMT1, KMT2, and KMT3 families, respectively. Here, an H3K9-specific DIM5/KMT1 orthologue, which lacks a C-terminal post-SET domain and localizes mainly in nucleus, is reported to have both conserved and noncanonical roles in methylating the H3 core lysines in Beauveria bassiana, an insect-pathogenic fungus serving as a main source of wide-spectrum fungal insecticides. Disruption of dim5 led to abolishment of H3K9me3 and marked attenuation of H3K4me1/me2, H3K9me1/me2 and H3K36me2. Consequently, the Δdim5 mutant lost the whole insect pathogenicity through normal cuticle infection, and was compromised severely in virulence through cuticle-bypassing infection (hemocoel injection) and also in a series of cellular events critical for the fungal virulence and lifecycle in vivo and in vitro, including reduced hyphal growth, blocked conidiation, impeded proliferation in vivo, altered carbohydrate epitopes, disturbed cell cycle, reduced biosynthesis and secretion of cuticle-degrading enzymes, and increased sensitivities to various stresses. Among 1,201 dysregulated genes (up/down ratio: 712:489) associated with those phenotypic changes, 92 (up/down ratio: 59:33) encode transcription factors and proteins or enzymes involved in posttranslational modifications, implying that the DIM5-methylated H3 core lysines could act as preferential marks of those transcription-active genes crucial for global gene regulation. These findings uncover a novel scenario of DIM5 and its indispensability for insect-pathogenic lifestyle and genome stability of B. bassiana.
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Affiliation(s)
- Kang Ren
- MOE Laboratory of Biosystems Homeostasis & Protection, Institute of Microbiology, College of Life Sciences, Zhejiang University, Hangzhou, China
| | - Ya-Ni Mou
- MOE Laboratory of Biosystems Homeostasis & Protection, Institute of Microbiology, College of Life Sciences, Zhejiang University, Hangzhou, China
| | - Sen-Miao Tong
- College of Agricultural and Food Science, Zhejiang A & F University, Lin'an, Zhejiang, China
| | - Sheng-Hua Ying
- MOE Laboratory of Biosystems Homeostasis & Protection, Institute of Microbiology, College of Life Sciences, Zhejiang University, Hangzhou, China
| | - Ming-Guang Feng
- MOE Laboratory of Biosystems Homeostasis & Protection, Institute of Microbiology, College of Life Sciences, Zhejiang University, Hangzhou, China
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Möller M, Habig M, Lorrain C, Feurtey A, Haueisen J, Fagundes WC, Alizadeh A, Freitag M, Stukenbrock EH. Recent loss of the Dim2 DNA methyltransferase decreases mutation rate in repeats and changes evolutionary trajectory in a fungal pathogen. PLoS Genet 2021; 17:e1009448. [PMID: 33750960 PMCID: PMC8016269 DOI: 10.1371/journal.pgen.1009448] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2020] [Revised: 04/01/2021] [Accepted: 02/26/2021] [Indexed: 01/04/2023] Open
Abstract
DNA methylation is found throughout all domains of life, yet the extent and function of DNA methylation differ among eukaryotes. Strains of the plant pathogenic fungus Zymoseptoria tritici appeared to lack cytosine DNA methylation (5mC) because gene amplification followed by Repeat-Induced Point mutation (RIP) resulted in the inactivation of the dim2 DNA methyltransferase gene. 5mC is, however, present in closely related sister species. We demonstrate that inactivation of dim2 occurred recently as some Z. tritici isolates carry a functional dim2 gene. Moreover, we show that dim2 inactivation occurred by a different path than previously hypothesized. We mapped the genome-wide distribution of 5mC in strains with or without functional dim2 alleles. Presence of functional dim2 correlates with high levels of 5mC in transposable elements (TEs), suggesting a role in genome defense. We identified low levels of 5mC in strains carrying non-functional dim2 alleles, suggesting that 5mC is maintained over time, presumably by an active Dnmt5 DNA methyltransferase. Integration of a functional dim2 allele in strains with mutated dim2 restored normal 5mC levels, demonstrating de novo cytosine methylation activity of Dim2. To assess the importance of 5mC for genome evolution, we performed an evolution experiment, comparing genomes of strains with high levels of 5mC to genomes of strains lacking functional dim2. We found that presence of a functional dim2 allele alters nucleotide composition by promoting C to T transitions (C→T) specifically at CpA (CA) sites during mitosis, likely contributing to TE inactivation. Our results show that 5mC density at TEs is a polymorphic trait in Z. tritici populations that can impact genome evolution.
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Affiliation(s)
- Mareike Möller
- Environmental Genomics, Christian-Albrechts University, Kiel, Germany
- Max Planck Institute for Evolutionary Biology, Plön, Germany
| | - Michael Habig
- Environmental Genomics, Christian-Albrechts University, Kiel, Germany
- Max Planck Institute for Evolutionary Biology, Plön, Germany
| | - Cécile Lorrain
- Environmental Genomics, Christian-Albrechts University, Kiel, Germany
- Max Planck Institute for Evolutionary Biology, Plön, Germany
| | - Alice Feurtey
- Environmental Genomics, Christian-Albrechts University, Kiel, Germany
- Max Planck Institute for Evolutionary Biology, Plön, Germany
| | - Janine Haueisen
- Environmental Genomics, Christian-Albrechts University, Kiel, Germany
- Max Planck Institute for Evolutionary Biology, Plön, Germany
| | - Wagner C. Fagundes
- Environmental Genomics, Christian-Albrechts University, Kiel, Germany
- Max Planck Institute for Evolutionary Biology, Plön, Germany
| | - Alireza Alizadeh
- Department of Plant Protection, Faculty of Agriculture, Azarbaijan Shahid Madani University, Tabriz, Iran
| | - Michael Freitag
- Department of Biochemistry and Biophysics, Oregon State University, Corvallis, OR, United States of America
| | - Eva H. Stukenbrock
- Environmental Genomics, Christian-Albrechts University, Kiel, Germany
- Max Planck Institute for Evolutionary Biology, Plön, Germany
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Yusuf AP, Abubakar MB, Malami I, Ibrahim KG, Abubakar B, Bello MB, Qusty N, Elazab ST, Imam MU, Alexiou A, Batiha GES. Zinc Metalloproteins in Epigenetics and Their Crosstalk. Life (Basel) 2021; 11:186. [PMID: 33652690 PMCID: PMC7996840 DOI: 10.3390/life11030186] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Revised: 02/22/2021] [Accepted: 02/23/2021] [Indexed: 12/13/2022] Open
Abstract
More than half a century ago, zinc was established as an essential micronutrient for normal human physiology. In silico data suggest that about 10% of the human proteome potentially binds zinc. Many proteins with zinc-binding domains (ZBDs) are involved in epigenetic modifications such as DNA methylation and histone modifications, which regulate transcription in physiological and pathological conditions. Zinc metalloproteins in epigenetics are mainly zinc metalloenzymes and zinc finger proteins (ZFPs), which are classified into writers, erasers, readers, editors, and feeders. Altogether, these classes of proteins engage in crosstalk that fundamentally maintains the epigenome's modus operandi. Changes in the expression or function of these proteins induced by zinc deficiency or loss of function mutations in their ZBDs may lead to aberrant epigenetic reprogramming, which may worsen the risk of non-communicable chronic diseases. This review attempts to address zinc's role and its proteins in natural epigenetic programming and artificial reprogramming and briefly discusses how the ZBDs in these proteins interact with the chromatin.
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Affiliation(s)
- Abdurrahman Pharmacy Yusuf
- Centre for Advanced Medical Research and Training, Usmanu Danfodiyo University, P.M.B. 2346 Sokoto, Nigeria; (A.P.Y.); (I.M.); (K.G.I.); (B.A.); (M.U.I.)
| | - Murtala Bello Abubakar
- Centre for Advanced Medical Research and Training, Usmanu Danfodiyo University, P.M.B. 2346 Sokoto, Nigeria; (A.P.Y.); (I.M.); (K.G.I.); (B.A.); (M.U.I.)
- Department of Physiology, Faculty of Basic Medical Sciences, College of Health Sciences, Usmanu Danfodiyo University, P.M.B. 2254 Sokoto, Nigeria
| | - Ibrahim Malami
- Centre for Advanced Medical Research and Training, Usmanu Danfodiyo University, P.M.B. 2346 Sokoto, Nigeria; (A.P.Y.); (I.M.); (K.G.I.); (B.A.); (M.U.I.)
- Department of Pharmacognosy and Ethnopharmacy, Faculty of Pharmaceutical Sciences, Usmanu Danfodiyo University, P.M.B. 2346 Sokoto, Nigeria
| | - Kasimu Ghandi Ibrahim
- Centre for Advanced Medical Research and Training, Usmanu Danfodiyo University, P.M.B. 2346 Sokoto, Nigeria; (A.P.Y.); (I.M.); (K.G.I.); (B.A.); (M.U.I.)
- Department of Physiology, Faculty of Basic Medical Sciences, College of Health Sciences, Usmanu Danfodiyo University, P.M.B. 2254 Sokoto, Nigeria
| | - Bilyaminu Abubakar
- Centre for Advanced Medical Research and Training, Usmanu Danfodiyo University, P.M.B. 2346 Sokoto, Nigeria; (A.P.Y.); (I.M.); (K.G.I.); (B.A.); (M.U.I.)
- Department of Pharmacology and Toxicology, Faculty of Pharmaceutical Sciences, Usmanu Danfodiyo University, P.M.B. 2346 Sokoto, Nigeria
| | - Muhammad Bashir Bello
- Centre for Advanced Medical Research and Training, Usmanu Danfodiyo University, P.M.B. 2346 Sokoto, Nigeria; (A.P.Y.); (I.M.); (K.G.I.); (B.A.); (M.U.I.)
- Department of Veterinary Microbiology, Faculty of Veterinary Medicine, Usmanu Danfodiyo University, P.M.B. 2346 Sokoto, Nigeria
| | - Naeem Qusty
- Medical Laboratories Department, Faculty of Applied Medical Sciences, Umm Al-Qura University, Mecca 21955, Saudi Arabia;
| | - Sara T. Elazab
- Department of Pharmacology, Faculty of Veterinary Medicine, Mansoura University, Mansoura, Dakahlia 35516, Egypt;
| | - Mustapha Umar Imam
- Centre for Advanced Medical Research and Training, Usmanu Danfodiyo University, P.M.B. 2346 Sokoto, Nigeria; (A.P.Y.); (I.M.); (K.G.I.); (B.A.); (M.U.I.)
- Department of Medical Biochemistry, Faculty of Basic Medical Sciences, College of Health Sciences, Usmanu Danfodiyo University, P.M.B. 2254 Sokoto, Nigeria
| | - Athanasios Alexiou
- Novel Global Community Educational Foundation, Hebersham, NSW 2770, Australia
- AFNP Med, Haidingergasse 29, 1030 Vienna, Austria
| | - Gaber El-Saber Batiha
- Department of Pharmacology and Therapeutics, Faculty of Veterinary Medicine, Damanhour University, Damanhour, AlBeheira 22511, Egypt
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Molecular Regulation of Circadian Chromatin. J Mol Biol 2020; 432:3466-3482. [PMID: 31954735 DOI: 10.1016/j.jmb.2020.01.009] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2019] [Revised: 12/13/2019] [Accepted: 01/07/2020] [Indexed: 02/06/2023]
Abstract
Circadian rhythms are generated by transcriptional negative feedback loops and require histone modifications and chromatin remodeling to ensure appropriate timing and amplitude of clock gene expression. Circadian modifications to histones are important for transcriptional initiation and feedback inhibition serving as signaling platform for chromatin-remodeling enzymes. Current models indicate circadian-regulated facultative heterochromatin (CRFH) is a conserved mechanism at clock genes in Neurospora, Drosophila, and mice. CRFH consists of antiphasic rhythms in activating and repressive modifications generating chromatin states that cycle between transcriptionally permissive and nonpermissive. There are rhythms in histone H3 lysine 9 and 27 acetylation (H3K9ac and H3K27ac) and histone H3 lysine 4 methylation (H3K4me) during activation; while deacetylation, histone H3 lysine 9 methylation (H3K9me) and heterochromatin protein 1 (HP1) are hallmarks of repression. ATP-dependent chromatin-remodeling enzymes control accessibility, nucleosome positioning/occupancy, and nuclear organization. In Neurospora, the rhythm in facultative heterochromatin is mediated by the frequency (frq) natural antisense transcript (NAT) qrf. While in mammals, histone deacetylases (HDACs), histone H3 lysine 9 methyltransferase (KMT1/SUV39), and components of nucleosome remodeling and deacetylase (NuRD) are part of the nuclear PERIOD complex (PER complex). Genomics efforts have found relationships among rhythmic chromatin modifications at clock-controlled genes (ccg) revealing circadian control of genome-wide chromatin states. There are also circadian clock-regulated lncRNAs with an emerging function that includes assisting in chromatin dynamics. In this review, we explore the connections between circadian clock, chromatin remodeling, lncRNAs, and CRFH and how these impact rhythmicity, amplitude, period, and phase of circadian clock genes.
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Zhu Q, Ramakrishnan M, Park J, Belden WJ. Histone H3 lysine 4 methyltransferase is required for facultative heterochromatin at specific loci. BMC Genomics 2019; 20:350. [PMID: 31068130 PMCID: PMC6505117 DOI: 10.1186/s12864-019-5729-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2019] [Accepted: 04/24/2019] [Indexed: 01/01/2023] Open
Abstract
Background Histone H3 lysine 4 tri-methylation (H3K4me3) and histone H3 lysine 9 tri-methylation (H3K9me3) are widely perceived to be opposing and often mutually exclusive chromatin modifications. However, both are needed for certain light-activated genes in Neurospora crassa (Neurospora), including frequency (frq) and vivid (vvd). Except for these 2 loci, little is known about how H3K4me3 and H3K9me3 impact and contribute to light-regulated gene expression. Results In this report, we performed a multi-dimensional genomic analysis to understand the role of H3K4me3 and H3K9me3 using the Neurospora light response as the system. RNA-seq on strains lacking H3 lysine 4 methyltransferase (KMT2/SET-1) and histone H3 lysine 9 methyltransferase (KMT1/DIM-5) revealed some light-activated genes had altered expression, but the light response was largely intact. Comparing these 2 mutants to wild-type (WT), we found that roughly equal numbers of genes showed elevated and reduced expression in the dark and the light making the environmental stimulus somewhat ancillary to the genome-wide effects. ChIP-seq experiments revealed H3K4me3 and H3K9me3 had only minor changes in response to light in WT, but there were notable alterations in H3K4me3 in Δkmt1/Δdim-5 and H3K9me3 in Δkmt2/Δset-1 indicating crosstalk and redistribution between the modifications. Integrated analysis of the RNA-seq and ChIP-seq highlighted context-dependent roles for KMT2/SET1 and KMT1/DIM-5 as either co-activators or co-repressors with some overlap as co-regulators. At a small subset of loci, H3K4 methylation is required for H3K9me3-mediated facultative heterochromatin including, the central clock gene frequency (frq). Finally, we used sequential ChIP (re-ChIP) experiment to confirm Neurospora contains K4/K9 bivalent domains. Conclusions Collectively, these data indicate there are obfuscated regulatory roles for H3K4 methylation and H3K9 methylation depending on genome location with some minor overlap and co-dependency. Electronic supplementary material The online version of this article (10.1186/s12864-019-5729-7) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Qiaoqiao Zhu
- Department of Animal Sciences, Rutgers, The State University of New Jersey, New Brunswick, NJ, 08901, USA
| | - Mukund Ramakrishnan
- Department of Animal Sciences, Rutgers, The State University of New Jersey, New Brunswick, NJ, 08901, USA.,Current Address: Department of Biological Sciences, IISER Berhampur, Berhampur, Ganjam, Odisha, 760010, India
| | - Jinhee Park
- Department of Animal Sciences, Rutgers, The State University of New Jersey, New Brunswick, NJ, 08901, USA
| | - William J Belden
- Department of Animal Sciences, Rutgers, The State University of New Jersey, New Brunswick, NJ, 08901, USA.
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Park J, Belden WJ. Long non-coding RNAs have age-dependent diurnal expression that coincides with age-related changes in genome-wide facultative heterochromatin. BMC Genomics 2018; 19:777. [PMID: 30373515 PMCID: PMC6206985 DOI: 10.1186/s12864-018-5170-3] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2018] [Accepted: 10/15/2018] [Indexed: 12/21/2022] Open
Abstract
Background Disrupted diurnal rhythms cause accelerated aging and an increased incidence in age-related disease and morbidity. The circadian clock governs cell physiology and metabolism by controlling transcription and chromatin. The goal of this study is to further understand the mechanism of age-related changes to circadian chromatin with a focus on facultative heterochromatin and diurnal non-coding RNAs. Results We performed a combined RNA-seq and ChIP-seq at two diurnal time-points for three different age groups to examine the connection between age-related changes to circadian transcription and heterochromatin in neuronal tissue. Our analysis focused on uncovering the relationships between long non-coding RNA (lncRNA) and age-related changes to histone H3 lysine 9 tri-methylation (H3K9me3), in part because the Period (Per) complex can direct facultative heterochromatin and models of aging suggest age-related changes to heterochromatin and DNA methylation. Our results reveal that lncRNAs and circadian output change dramatically with age, but the core clock genes remain rhythmic. Age-related changes in clock-controlled gene (ccg) expression indicate there are age-dependent circadian output that change from anabolic to catabolic processes during aging. In addition, there are diurnal and age-related changes in H3K9me3 that coincide with changes in transcription. Conclusions The data suggest a model where some age-related changes in diurnal expression are partially attributed to age-related alterations to rhythmic facultative heterochromatin. The changes in heterochromatin are potentially mediated by changes in diurnal lncRNA creating an interlocked circadian-chromatin regulatory network that undergoes age-dependent metamorphosis. Electronic supplementary material The online version of this article (10.1186/s12864-018-5170-3) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Jinhee Park
- Department of Animal Sciences, Rutgers, The State University of New Jersey, New Brunswick, NJ, 08901, USA
| | - William J Belden
- Department of Animal Sciences, Rutgers, The State University of New Jersey, New Brunswick, NJ, 08901, USA.
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Abstract
Transposable elements have colonized the genomes of nearly all organisms, including fungi. Although transposable elements may sometimes provide beneficial functions to their hosts their overall impact is considered deleterious. As a result, the activity of transposable elements needs to be counterbalanced by the host genome defenses. In fungi, the primary genome defense mechanisms include repeat-induced point mutation (RIP) and methylation induced premeiotically, meiotic silencing by unpaired DNA, sex-induced silencing, cosuppression (also known as somatic quelling), and cotranscriptional RNA surveillance. Recent studies of the filamentous fungus Neurospora crassa have shown that the process of repeat recognition for RIP apparently involves interactions between coaligned double-stranded segments of chromosomal DNA. These studies have also shown that RIP can be mediated by the conserved pathway that establishes transcriptional (heterochromatic) silencing of repetitive DNA. In light of these new findings, RIP emerges as a specialized case of the general phenomenon of heterochromatic silencing of repetitive DNA.
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Abstract
ABSTRACT
Life, as we know it, would not be possible without light. Light is not only a primary source of energy, but also an important source of information for many organisms. To sense light, only a few photoreceptor systems have developed during evolution. They are all based on an organic molecule with conjugated double bonds that allows energy transfer from visible (or UV) light to its cognate protein to translate the primary physical photoresponse to cell-biological actions. The three main classes of receptors are flavin-based blue-light, retinal-based green-light (such as rhodopsin), and linear tetrapyrrole-based red-light sensors. Light not only controls the behavior of motile organisms, but is also important for many sessile microorganisms including fungi. In fungi, light controls developmental decisions and physiological adaptations as well as the circadian clock. Although all major classes of photoreceptors are found in fungi, a good level of understanding of the signaling processes at the molecular level is limited to some model fungi. However, current knowledge suggests a complex interplay between light perception systems, which goes far beyond the simple sensing of light and dark. In this article we focus on recent results in several fungi, which suggest a strong link between light-sensing and stress-activated mitogen-activated protein kinases.
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Fuller K, Dunlap J, Loros J. Fungal Light Sensing at the Bench and Beyond. ADVANCES IN GENETICS 2016; 96:1-51. [DOI: 10.1016/bs.adgen.2016.08.002] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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Dasgupta A, Fuller KK, Dunlap JC, Loros JJ. Seeing the world differently: variability in the photosensory mechanisms of two model fungi. Environ Microbiol 2015; 18:5-20. [PMID: 26373782 DOI: 10.1111/1462-2920.13055] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2015] [Revised: 09/01/2015] [Accepted: 09/12/2015] [Indexed: 12/14/2022]
Abstract
Light plays an important role for most organisms on this planet, serving either as a source of energy or information for the adaptation of biological processes to specific times of day. The fungal kingdom is estimated to contain well over a million species, possibly 10-fold more, and it is estimated that a majority of the fungi respond to light, eliciting changes in several physiological characteristics including pathogenesis, development and secondary metabolism. Two model organisms for photobiological studies have taken centre-stage over the last few decades--Neurospora crassa and Aspergillus nidulans. In this review, we will first discuss our understanding of the light response in N. crassa, about which the most is known, and will then juxtapose N. crassa with A. nidulans, which, as will be described below, provides an excellent template for understanding photosensory cross-talk. Finally, we will end with a commentary on the variability of the light response among other relevant fungi, and how our molecular understanding in the aforementioned model organisms still provides a strong base for dissecting light responses in such species.
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Affiliation(s)
- Arko Dasgupta
- Department of Genetics, Geisel School of Medicine at Dartmouth, Hanover, NH, USA
| | - Kevin K Fuller
- Department of Genetics, Geisel School of Medicine at Dartmouth, Hanover, NH, USA
| | - Jay C Dunlap
- Department of Genetics, Geisel School of Medicine at Dartmouth, Hanover, NH, USA
| | - Jennifer J Loros
- Department of Biochemistry, Geisel School of Medicine at Dartmouth, Hanover, NH, USA
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Proietto M, Bianchi MM, Ballario P, Brenna A. Epigenetic and Posttranslational Modifications in Light Signal Transduction and the Circadian Clock in Neurospora crassa. Int J Mol Sci 2015; 16:15347-83. [PMID: 26198228 PMCID: PMC4519903 DOI: 10.3390/ijms160715347] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2015] [Revised: 06/24/2015] [Accepted: 06/30/2015] [Indexed: 12/15/2022] Open
Abstract
Blue light, a key abiotic signal, regulates a wide variety of physiological processes in many organisms. One of these phenomena is the circadian rhythm presents in organisms sensitive to the phase-setting effects of blue light and under control of the daily alternation of light and dark. Circadian clocks consist of autoregulatory alternating negative and positive feedback loops intimately connected with the cellular metabolism and biochemical processes. Neurospora crassa provides an excellent model for studying the molecular mechanisms involved in these phenomena. The White Collar Complex (WCC), a blue-light receptor and transcription factor of the circadian oscillator, and Frequency (FRQ), the circadian clock pacemaker, are at the core of the Neurospora circadian system. The eukaryotic circadian clock relies on transcriptional/translational feedback loops: some proteins rhythmically repress their own synthesis by inhibiting the activity of their transcriptional factors, generating self-sustained oscillations over a period of about 24 h. One of the basic mechanisms that perpetuate self-sustained oscillations is post translation modification (PTM). The acronym PTM generically indicates the addition of acetyl, methyl, sumoyl, or phosphoric groups to various types of proteins. The protein can be regulatory or enzymatic or a component of the chromatin. PTMs influence protein stability, interaction, localization, activity, and chromatin packaging. Chromatin modification and PTMs have been implicated in regulating circadian clock function in Neurospora. Research into the epigenetic control of transcription factors such as WCC has yielded new insights into the temporal modulation of light-dependent gene transcription. Here we report on epigenetic and protein PTMs in the regulation of the Neurospora crassa circadian clock. We also present a model that illustrates the molecular mechanisms at the basis of the blue light control of the circadian clock.
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Affiliation(s)
- Marco Proietto
- Department of Biology and Biotechnologies "Charles Darwin", Sapienza-University of Rome, Piazzale Aldo Moro 5, Rome 00185, Italy.
| | - Michele Maria Bianchi
- Department of Biology and Biotechnologies "Charles Darwin", Sapienza-University of Rome, Piazzale Aldo Moro 5, Rome 00185, Italy.
| | - Paola Ballario
- Department of Biology and Biotechnologies "Charles Darwin", Sapienza-University of Rome, Piazzale Aldo Moro 5, Rome 00185, Italy.
- Pasteur Institute, Cenci Bolognetti Foundation and Department of Biology and Biotechnology "Charles Darwin", Sapienza-University of Rome, Piazzale Aldo Moro 5, Rome 00185, Italy.
| | - Andrea Brenna
- Department of Biology and Biotechnologies "Charles Darwin", Sapienza-University of Rome, Piazzale Aldo Moro 5, Rome 00185, Italy.
- Pasteur Institute, Cenci Bolognetti Foundation and Department of Biology and Biotechnology "Charles Darwin", Sapienza-University of Rome, Piazzale Aldo Moro 5, Rome 00185, Italy.
- Department of Biology, Division of Biochemistry, University of Fribourg, Chemin du Musée 5, Fribourg 1700, Switzerland.
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The frequency natural antisense transcript first promotes, then represses, frequency gene expression via facultative heterochromatin. Proc Natl Acad Sci U S A 2015; 112:4357-62. [PMID: 25831497 DOI: 10.1073/pnas.1406130112] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The circadian clock is controlled by a network of interconnected feedback loops that require histone modifications and chromatin remodeling. Long noncoding natural antisense transcripts (NATs) originate from Period in mammals and frequency (frq) in Neurospora. To understand the role of NATs in the clock, we put the frq antisense transcript qrf (frq spelled backwards) under the control of an inducible promoter. Replacing the endogenous qrf promoter altered heterochromatin formation and DNA methylation at frq. In addition, constitutive, low-level induction of qrf caused a dramatic effect on the endogenous rhythm and elevated circadian output. Surprisingly, even though qrf is needed for heterochromatic silencing, induction of qrf initially promoted frq gene expression by creating a more permissible local chromatin environment. The observation that antisense expression can initially promote sense gene expression before silencing via heterochromatin formation at convergent loci is also found when a NAT to hygromycin resistance gene is driven off the endogenous vivid (vvd) promoter in the Δvvd strain. Facultative heterochromatin silencing at frq functions in a parallel pathway to previously characterized VVD-dependent silencing and is needed to establish the appropriate circadian phase. Thus, repression via dicer-independent siRNA-mediated facultative heterochromatin is largely independent of, and occurs alongside, other feedback processes.
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Regulated DNA methylation and the circadian clock: implications in cancer. BIOLOGY 2014; 3:560-77. [PMID: 25198253 PMCID: PMC4192628 DOI: 10.3390/biology3030560] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/07/2014] [Revised: 08/12/2014] [Accepted: 08/15/2014] [Indexed: 01/10/2023]
Abstract
Since the cloning and discovery of DNA methyltransferases (DNMT), there has been a growing interest in DNA methylation, its role as an epigenetic modification, how it is established and removed, along with the implications in development and disease. In recent years, it has become evident that dynamic DNA methylation accompanies the circadian clock and is found at clock genes in Neurospora, mice and cancer cells. The relationship among the circadian clock, cancer and DNA methylation at clock genes suggests a correlative indication that improper DNA methylation may influence clock gene expression, contributing to the etiology of cancer. The molecular mechanism underlying DNA methylation at clock loci is best studied in the filamentous fungi, Neurospora crassa, and recent data indicate a mechanism analogous to the RNA-dependent DNA methylation (RdDM) or RNAi-mediated facultative heterochromatin. Although it is still unclear, DNA methylation at clock genes may function as a terminal modification that serves to prevent the regulated removal of histone modifications. In this capacity, aberrant DNA methylation may serve as a readout of misregulated clock genes and not as the causative agent. This review explores the implications of DNA methylation at clock loci and describes what is currently known regarding the molecular mechanism underlying DNA methylation at circadian clock genes.
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