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Abstract
Embryogenesis is characterized by dynamic chromatin remodeling and broad changes in chromosome architecture. These changes in chromatin organization are accompanied by transcriptional changes, which are crucial for the proper development of the embryo. Several independent mechanisms regulate this process of chromatin reorganization, including segregation of chromatin into heterochromatin and euchromatin, deposition of active and repressive histone modifications, and the formation of 3D chromatin domains such as TADs and LADs. These changes in chromatin structure are directly linked to developmental milestones such as the loss of developmental plasticity and acquisition of terminally differentiated cell identities. In this review we summarize these processes that underlie this chromatin reorganization and their impact on embryogenesis in the nematode C. elegans.
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Affiliation(s)
- Eshna Jash
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Györgyi Csankovszki
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA
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2
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Millán-Zambrano G, Burton A, Bannister AJ, Schneider R. Histone post-translational modifications - cause and consequence of genome function. Nat Rev Genet 2022; 23:563-580. [PMID: 35338361 DOI: 10.1038/s41576-022-00468-7] [Citation(s) in RCA: 482] [Impact Index Per Article: 160.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/28/2022] [Indexed: 12/16/2022]
Abstract
Much has been learned since the early 1960s about histone post-translational modifications (PTMs) and how they affect DNA-templated processes at the molecular level. This understanding has been bolstered in the past decade by the identification of new types of histone PTM, the advent of new genome-wide mapping approaches and methods to deposit or remove PTMs in a locally and temporally controlled manner. Now, with the availability of vast amounts of data across various biological systems, the functional role of PTMs in important processes (such as transcription, recombination, replication, DNA repair and the modulation of genomic architecture) is slowly emerging. This Review explores the contribution of histone PTMs to the regulation of genome function by discussing when these modifications play a causative (or instructive) role in DNA-templated processes and when they are deposited as a consequence of such processes, to reinforce and record the event. Important advances in the field showing that histone PTMs can exert both direct and indirect effects on genome function are also presented.
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Affiliation(s)
- Gonzalo Millán-Zambrano
- Centro Andaluz de Biología Molecular y Medicina Regenerativa CABIMER, Universidad de Sevilla-CSIC-Universidad Pablo de Olavide, Seville, Spain
- Departamento de Genética, Facultad de Biología, Universidad de Sevilla, Seville, Spain
| | - Adam Burton
- Institute of Epigenetics and Stem Cells, Helmholtz Center Munich, Munich, Germany
| | - Andrew J Bannister
- Gurdon Institute and Department of Pathology, University of Cambridge, Cambridge, UK.
| | - Robert Schneider
- Institute of Functional Epigenetics, Helmholtz Center Munich, Munich, Germany.
- Faculty of Biology, Ludwig Maximilian University (LMU) of Munich, Munich, Germany.
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3
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Fry AL, Webster AK, Burnett J, Chitrakar R, Baugh LR, Hubbard EJA. DAF-18/PTEN inhibits germline zygotic gene activation during primordial germ cell quiescence. PLoS Genet 2021; 17:e1009650. [PMID: 34288923 PMCID: PMC8294487 DOI: 10.1371/journal.pgen.1009650] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Accepted: 06/08/2021] [Indexed: 12/13/2022] Open
Abstract
Quiescence, an actively-maintained reversible state of cell cycle arrest, is not well understood. PTEN is one of the most frequently lost tumor suppressors in human cancers and regulates quiescence of stem cells and cancer cells. The sole PTEN ortholog in Caenorhabditis elegans is daf-18. In a C. elegans loss-of-function mutant for daf-18, primordial germ cells (PGCs) divide inappropriately in L1 larvae hatched into starvation conditions, in a TOR-dependent manner. Here, we further investigated the role of daf-18 in maintaining PGC quiescence in L1 starvation. We found that maternal or zygotic daf-18 is sufficient to maintain cell cycle quiescence, that daf-18 acts in the germ line and soma, and that daf-18 affects timing of PGC divisions in fed animals. Importantly, our results also implicate daf-18 in repression of germline zygotic gene activation, though not in germline fate specification. However, TOR is less important to germline zygotic gene expression, suggesting that in the absence of food, daf-18/PTEN prevents inappropriate germline zygotic gene activation and cell division by distinct mechanisms.
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Affiliation(s)
- Amanda L. Fry
- Skirball Institute of Biomolecular Medicine, Department of Cell Biology, NYU Grossman School of Medicine, New York, New York, United States of America
| | - Amy K. Webster
- Department of Biology, Center for Genomic and Computational Biology, Duke University, Durham, North Carolina, United States of America
| | - Julia Burnett
- Skirball Institute of Biomolecular Medicine, Department of Cell Biology, NYU Grossman School of Medicine, New York, New York, United States of America
| | - Rojin Chitrakar
- Department of Biology, Center for Genomic and Computational Biology, Duke University, Durham, North Carolina, United States of America
| | - L. Ryan Baugh
- Department of Biology, Center for Genomic and Computational Biology, Duke University, Durham, North Carolina, United States of America
| | - E. Jane Albert Hubbard
- Skirball Institute of Biomolecular Medicine, Department of Cell Biology, NYU Grossman School of Medicine, New York, New York, United States of America
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4
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Wang S, Meyer DH, Schumacher B. H3K4me2 regulates the recovery of protein biosynthesis and homeostasis following DNA damage. Nat Struct Mol Biol 2020; 27:1165-1177. [DOI: 10.1038/s41594-020-00513-1] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2019] [Accepted: 09/02/2020] [Indexed: 01/08/2023]
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Nhan JD, Turner CD, Anderson SM, Yen CA, Dalton HM, Cheesman HK, Ruter DL, Uma Naresh N, Haynes CM, Soukas AA, Pukkila-Worley R, Curran SP. Redirection of SKN-1 abates the negative metabolic outcomes of a perceived pathogen infection. Proc Natl Acad Sci U S A 2019; 116:22322-22330. [PMID: 31611372 PMCID: PMC6825279 DOI: 10.1073/pnas.1909666116] [Citation(s) in RCA: 61] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Early host responses toward pathogens are essential for defense against infection. In Caenorhabditis elegans, the transcription factor, SKN-1, regulates cellular defenses during xenobiotic intoxication and bacterial infection. However, constitutive activation of SKN-1 results in pleiotropic outcomes, including a redistribution of somatic lipids to the germline, which impairs health and shortens lifespan. Here, we show that exposing C. elegans to Pseudomonas aeruginosa similarly drives the rapid depletion of somatic, but not germline, lipid stores. Modulating the epigenetic landscape refines SKN-1 activity away from innate immunity targets, which alleviates negative metabolic outcomes. Similarly, exposure to oxidative stress redirects SKN-1 activity away from pathogen response genes while restoring somatic lipid distribution. In addition, activating p38/MAPK signaling in the absence of pathogens, is sufficient to drive SKN-1-dependent loss of somatic fat. These data define a SKN-1- and p38-dependent axis for coordinating pathogen responses, lipid homeostasis, and survival and identify transcriptional redirection, rather than inactivation, as a mechanism for counteracting the pleiotropic consequences of aberrant transcriptional activity.
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Affiliation(s)
- James D Nhan
- Leonard Davis School of Gerontology, University of Southern California, Los Angeles, CA 90089
- Department of Molecular and Computation Biology, Dornsife College of Letters, Arts, and Sciences, University of Southern California, Los Angeles, CA 90089
| | - Christian D Turner
- Leonard Davis School of Gerontology, University of Southern California, Los Angeles, CA 90089
- Department of Molecular and Computation Biology, Dornsife College of Letters, Arts, and Sciences, University of Southern California, Los Angeles, CA 90089
| | - Sarah M Anderson
- Program in Innate Immunity, Division of Infectious Diseases and Immunology, University of Massachusetts Medical School, Worcester, MA 01655
| | - Chia-An Yen
- Leonard Davis School of Gerontology, University of Southern California, Los Angeles, CA 90089
- Department of Molecular and Computation Biology, Dornsife College of Letters, Arts, and Sciences, University of Southern California, Los Angeles, CA 90089
| | - Hans M Dalton
- Leonard Davis School of Gerontology, University of Southern California, Los Angeles, CA 90089
- Department of Molecular and Computation Biology, Dornsife College of Letters, Arts, and Sciences, University of Southern California, Los Angeles, CA 90089
| | - Hilary K Cheesman
- Program in Innate Immunity, Division of Infectious Diseases and Immunology, University of Massachusetts Medical School, Worcester, MA 01655
| | - Dana L Ruter
- Biology Department, Integrative Program for Biological and Genome Sciences, University of North Carolina, Chapel Hill, NC 27599
| | - Nandhitha Uma Naresh
- Department of Molecular, Cell and Cancer Biology, University of Massachusetts Medical School, Worcester, MA 01655
| | - Cole M Haynes
- Department of Molecular, Cell and Cancer Biology, University of Massachusetts Medical School, Worcester, MA 01655
| | - Alexander A Soukas
- Center for Human Genetic Research and Diabetes Unit, Department of Medicine, Massachusetts General Hospital, Boston, MA 02114
| | - Read Pukkila-Worley
- Program in Innate Immunity, Division of Infectious Diseases and Immunology, University of Massachusetts Medical School, Worcester, MA 01655;
| | - Sean P Curran
- Leonard Davis School of Gerontology, University of Southern California, Los Angeles, CA 90089;
- Department of Molecular and Computation Biology, Dornsife College of Letters, Arts, and Sciences, University of Southern California, Los Angeles, CA 90089
- Norris Comprehensive Cancer Center, Keck School of Medicine, University of Southern California, Los Angeles, CA 90089
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6
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Miwa T, Inoue K, Sakamoto H. MRG-1 is required for both chromatin-based transcriptional silencing and genomic integrity of primordial germ cells in Caenorhabditis elegans. Genes Cells 2019; 24:377-389. [PMID: 30929290 DOI: 10.1111/gtc.12683] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Revised: 02/21/2019] [Accepted: 03/21/2019] [Indexed: 11/30/2022]
Abstract
In Caenorhabditis elegans, germline cells remain transcriptionally silenced during embryogenesis. The transcriptional silencing is achieved by two different mechanisms: One is the inhibition of RNA polymerase II in P2-P4 cells at the establishment stage, and another is chromatin-based silencing in two primordial germ cells (PGCs) at the maintenance stage; however, the molecular mechanism underlying chromatin-based silencing is less understood. We investigated the role of the chromodomain protein MRG-1, which is an essential maternal factor for germline development, in transcriptional silencing in PGCs. PGCs lacking maternal MRG-1 showed increased levels of two histone modifications (H3K4me2 and H4K16ac), which are epigenetic markers for active transcription, and precocious activation of germline promoters. Loss of MES-4, a H3K36 methyltransferase, also caused similar derepression of the germline genes in PGCs, suggesting that both MRG-1 and MES-4 function in chromatin-based silencing in PGCs. In addition, the mrg-1 null mutant showed abnormal chromosome structures and a decrease in homologous recombinase RAD-51 foci in PGCs, but the mes-4 null mutant did not show such phenotypes. Taken together, we propose that MRG-1 has two distinct functions: chromatin-based transcriptional silencing and preserving genomic integrity at the maintenance stage of PGCs.
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Affiliation(s)
- Takashi Miwa
- Department of Biology, Graduate School of Science, Kobe University, Kobe, Japan
| | - Kunio Inoue
- Department of Biology, Graduate School of Science, Kobe University, Kobe, Japan
| | - Hiroshi Sakamoto
- Department of Biology, Graduate School of Science, Kobe University, Kobe, Japan
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Lussi YC, Mariani L, Friis C, Peltonen J, Myers TR, Krag C, Wong G, Salcini AE. Impaired removal of H3K4 methylation affects cell fate determination and gene transcription. Development 2016; 143:3751-3762. [PMID: 27578789 DOI: 10.1242/dev.139139] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2016] [Accepted: 08/20/2016] [Indexed: 01/30/2023]
Abstract
Methylation of histone 3 lysine 4 (H3K4) is largely associated with promoters and enhancers of actively transcribed genes and is finely regulated during development by the action of histone methyltransferases and demethylases. H3K4me3 demethylases of the KDM5 family have been previously implicated in development, but how the regulation of H3K4me3 level controls developmental processes is not fully established. Here, we show that the H3K4 demethylase RBR-2, the unique member of the KDM5 family in C. elegans, acts cell-autonomously and in a catalytic-dependent manner to control vulva precursor cells fate acquisition, by promoting the LIN-12/Notch pathway. Using genome-wide approaches, we show that RBR-2 reduces the H3K4me3 level at transcription start sites (TSSs) and in regions upstream of the TSSs, and acts both as a transcription repressor and activator. Analysis of the lin-11 genetic locus, a direct RBR-2 target gene required for vulva precursor cell fate acquisition, shows that RBR-2 controls the epigenetic signature of the lin-11 vulva-specific enhancer and lin-11 expression, providing in vivo evidence that RBR-2 can positively regulate transcription and cell fate acquisition by controlling enhancer activity.
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Affiliation(s)
- Yvonne C Lussi
- Biotech Research and Innovation Centre (BRIC), University of Copenhagen, Copenhagen DK-2200, Denmark.,Centre for Epigenetics, University of Copenhagen, Copenhagen DK-2200, Denmark
| | - Luca Mariani
- Biotech Research and Innovation Centre (BRIC), University of Copenhagen, Copenhagen DK-2200, Denmark.,Centre for Epigenetics, University of Copenhagen, Copenhagen DK-2200, Denmark
| | - Carsten Friis
- Biotech Research and Innovation Centre (BRIC), University of Copenhagen, Copenhagen DK-2200, Denmark.,Centre for Epigenetics, University of Copenhagen, Copenhagen DK-2200, Denmark
| | - Juhani Peltonen
- A. I. Virtanen Institute for Molecular Sciences, Department of Neurobiology, University of Eastern Finland, Kuopio 70211, Finland
| | - Toshia R Myers
- Biotech Research and Innovation Centre (BRIC), University of Copenhagen, Copenhagen DK-2200, Denmark.,Centre for Epigenetics, University of Copenhagen, Copenhagen DK-2200, Denmark
| | - Claudia Krag
- Biotech Research and Innovation Centre (BRIC), University of Copenhagen, Copenhagen DK-2200, Denmark
| | - Garry Wong
- A. I. Virtanen Institute for Molecular Sciences, Department of Neurobiology, University of Eastern Finland, Kuopio 70211, Finland
| | - Anna Elisabetta Salcini
- Biotech Research and Innovation Centre (BRIC), University of Copenhagen, Copenhagen DK-2200, Denmark .,Centre for Epigenetics, University of Copenhagen, Copenhagen DK-2200, Denmark
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8
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Vandamme J, Sidoli S, Mariani L, Friis C, Christensen J, Helin K, Jensen ON, Salcini AE. H3K23me2 is a new heterochromatic mark in Caenorhabditis elegans. Nucleic Acids Res 2015; 43:9694-710. [PMID: 26476455 PMCID: PMC4787770 DOI: 10.1093/nar/gkv1063] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2015] [Accepted: 10/01/2015] [Indexed: 12/05/2022] Open
Abstract
Genome-wide analyses in Caenorhabditis elegans show that post-translational modifications (PTMs) of histones are evolutionary conserved and distributed along functionally distinct genomic domains. However, a global profile of PTMs and their co-occurrence on the same histone tail has not been described in this organism. We used mass spectrometry based middle-down proteomics to analyze histone H3 N-terminal tails from C. elegans embryos for the presence, the relative abundance and the potential cross-talk of co-existing PTMs. This analysis highlighted that the lysine 23 of histone H3 (H3K23) is extensively modified by methylation and that tri-methylated H3K9 (H3K9me3) is exclusively detected on histone tails with di-methylated H3K23 (H3K23me2). Chromatin immunoprecipitation approaches revealed a positive correlation between H3K23me2 and repressive marks. By immunofluorescence analyses, H3K23me2 appears differentially regulated in germ and somatic cells, in part by the action of the histone demethylase JMJD-1.2. H3K23me2 is enriched in heterochromatic regions, localizing in H3K9me3 and heterochromatin protein like-1 (HPL-1)-positive foci. Biochemical analyses indicated that HPL-1 binds to H3K23me2 and interacts with a conserved CoREST repressive complex. Thus, our study suggests that H3K23me2 defines repressive domains and contributes to organizing the genome in distinct heterochromatic regions during embryogenesis.
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Affiliation(s)
- Julien Vandamme
- Biotech Research & Innovation Centre (BRIC), University of Copenhagen, Ole Maaløes Vej 5, 2200 Copenhagen N, Denmark Centre for Epigenetics, University of Copenhagen, Ole Maaløes Vej 5, 2200 Copenhagen N, Denmark
| | - Simone Sidoli
- Centre for Epigenetics, Department of Biochemistry and Molecular Biology, University of Southern Denmark, 5230 Odense M, Denmark VILLUM Center for Bioanalytical Sciences, University of Southern Denmark, 5230 Odense M, Denmark
| | - Luca Mariani
- Biotech Research & Innovation Centre (BRIC), University of Copenhagen, Ole Maaløes Vej 5, 2200 Copenhagen N, Denmark Centre for Epigenetics, University of Copenhagen, Ole Maaløes Vej 5, 2200 Copenhagen N, Denmark
| | - Carsten Friis
- Biotech Research & Innovation Centre (BRIC), University of Copenhagen, Ole Maaløes Vej 5, 2200 Copenhagen N, Denmark Centre for Epigenetics, University of Copenhagen, Ole Maaløes Vej 5, 2200 Copenhagen N, Denmark
| | - Jesper Christensen
- Biotech Research & Innovation Centre (BRIC), University of Copenhagen, Ole Maaløes Vej 5, 2200 Copenhagen N, Denmark Centre for Epigenetics, University of Copenhagen, Ole Maaløes Vej 5, 2200 Copenhagen N, Denmark
| | - Kristian Helin
- Biotech Research & Innovation Centre (BRIC), University of Copenhagen, Ole Maaløes Vej 5, 2200 Copenhagen N, Denmark Centre for Epigenetics, University of Copenhagen, Ole Maaløes Vej 5, 2200 Copenhagen N, Denmark The Danish Stem Cell Centre (Danstem), University of Copenhagen, Blegdamsvej 3, 2200 Copenhagen, Denmark
| | - Ole N Jensen
- Centre for Epigenetics, Department of Biochemistry and Molecular Biology, University of Southern Denmark, 5230 Odense M, Denmark VILLUM Center for Bioanalytical Sciences, University of Southern Denmark, 5230 Odense M, Denmark
| | - Anna Elisabetta Salcini
- Biotech Research & Innovation Centre (BRIC), University of Copenhagen, Ole Maaløes Vej 5, 2200 Copenhagen N, Denmark Centre for Epigenetics, University of Copenhagen, Ole Maaløes Vej 5, 2200 Copenhagen N, Denmark
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9
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Vágnerová L, Gombitová A, Cmarko D, Lanctôt C. Distinct chromatin organization in the germ line founder cell of the Caenorhabditis elegans embryo. Dev Growth Differ 2014; 56:605-14. [PMID: 25279455 DOI: 10.1111/dgd.12160] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2014] [Revised: 08/21/2014] [Accepted: 08/21/2014] [Indexed: 12/01/2022]
Abstract
Cells belonging to the germ lineage segregate physically and molecularly from their somatic neighbors during embryogenesis. While germ line-specific chromatin modifications have been identified at later stages in the Caenorhabditis elegans nematode, none have been found in the single P4 germ line founder cell that arises at the beginning of gastrulation. Using light and electron microscopy, we now report that the chromatin organization in the germ line founder cell of the early C. elegans embryo is distinct from that in the neighboring somatic cells. This unique organization is characterized by a greater chromatin compaction and an expansion of the interchromatin compartment. The ultrastructure of individual chromatin domains does not differ between germ line and somatic cells, pointing to a specific organization mainly at the level of the whole nucleus. We show that this higher order reorganization of chromatin is not a consequence of the P4 nucleus being smaller than somatic nuclei or having initiated mitosis. Imaging of living embryos expressing fluorescent markers for both chromatin and P granules revealed that the appearance of a distinct chromatin organization in the P4 cell occurs approximately 10 min after its birth and coincides with the aggregation of P granules around the nucleus, suggesting a possible link between these two events. The higher order reorganization of chromatin that is reported here occurs during the establishment of definitive germ cell identity. The changes we have observed could therefore be a prerequisite for the programming of chromatin totipotency.
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Affiliation(s)
- Lenka Vágnerová
- Institute of Cellular Biology and Pathology, First Faculty of Medicine, Charles University in Prague, Prague, Czech Republic
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Käser-Pébernard S, Müller F, Wicky C. LET-418/Mi2 and SPR-5/LSD1 cooperatively prevent somatic reprogramming of C. elegans germline stem cells. Stem Cell Reports 2014; 2:547-59. [PMID: 24749077 PMCID: PMC3986580 DOI: 10.1016/j.stemcr.2014.02.007] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2013] [Revised: 02/21/2014] [Accepted: 02/21/2014] [Indexed: 11/15/2022] Open
Abstract
Throughout their journey to forming new individuals, germline stem cells must remain totipotent, particularly by maintaining a specific chromatin structure. However, the place epigenetic factors occupy in this process remains elusive. So far, “sensitization” of chromatin by modulation of histone arrangement and/or content was believed to facilitate transcription-factor-induced germ cell reprogramming. Here, we demonstrate that the combined reduction of two epigenetic factors suffices to reprogram C. elegans germ cells. The histone H3K4 demethylase SPR-5/LSD1 and the chromatin remodeler LET-418/Mi2 function together in an early process to maintain germ cell status and act as a barrier to block precocious differentiation. This epigenetic barrier is capable of limiting COMPASS-mediated H3K4 methylation, because elevated H3K4me3 levels correlate with germ cell reprogramming in spr-5; let-418 mutants. Interestingly, germ cells deficient for spr-5 and let-418 mainly reprogram as neurons, suggesting that neuronal fate might be the first to be derepressed in early embryogenesis. SPR-5/LSD1 and LET-418/Mi2 interact to jointly control germ cell status C. elegans germ cells reprogram as neurons in spr-5 let-418 mutants SPR-5 and LET-418 counteract COMPASS-dependent H3K4 methylation in the germline High H3K4me3 levels in germ cells correlate with somatic reprogramming
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Affiliation(s)
| | - Fritz Müller
- Department of Zoology, University of Fribourg, Chemin du musée 10, 1700 Fribourg, Switzerland
| | - Chantal Wicky
- Department of Zoology, University of Fribourg, Chemin du musée 10, 1700 Fribourg, Switzerland
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Fisher K, Gee F, Wang S, Xue F, Knapp S, Philpott M, Wells C, Rodriguez M, Snoek LB, Kammenga J, Poulin GB. Maintenance of muscle myosin levels in adult C. elegans requires both the double bromodomain protein BET-1 and sumoylation. Biol Open 2013; 2:1354-63. [PMID: 24285704 PMCID: PMC3863420 DOI: 10.1242/bio.20136007] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Attenuation of RAS-mediated signalling is a conserved process essential to control cell proliferation, differentiation, and apoptosis. Cooperative interactions between histone modifications such as acetylation, methylation and sumoylation are crucial for proper attenuation in C. elegans, implying that the proteins recognising these histone modifications could also play an important role in attenuation of RAS-mediated signalling. We sought to systematically identify these proteins and found BET-1. BET-1 is a conserved double bromodomain protein that recognises acetyl-lysines on histone tails and maintains the stable fate of various lineages. Unexpectedly, adults lacking both BET-1 and SUMO-1 are depleted of muscle myosin, an essential component of myofibrils. We also show that this muscle myosin depletion does not occur in all animals at a specific time, but rather that the penetrance of the phenotype increases with age. To gain mechanistic insights into this process, we sought to delay the occurrence of the muscle myosin depletion phenotype and found that it requires caspase activity and MEK-dependent signalling. We also performed transcription profiling on these mutants and found an up-regulation of the FGF receptor, egl-15, a tyrosine kinase receptor acting upstream of MEK. Consistent with a MEK requirement, we could delay the muscle phenotype by systemic or hypodermal knock down of egl-15. Thus, this work uncovered a caspase- and MEK-dependent mechanism that acts specifically on ageing adults to maintain the appropriate net level of muscle myosin.
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Affiliation(s)
- Kate Fisher
- Faculty of Life Sciences, Michael Smith Building, University of Manchester, Oxford Road, Manchester M13 9PT, UK
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Han S, Brunet A. Histone methylation makes its mark on longevity. Trends Cell Biol 2011; 22:42-9. [PMID: 22177962 DOI: 10.1016/j.tcb.2011.11.001] [Citation(s) in RCA: 144] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2011] [Revised: 11/07/2011] [Accepted: 11/08/2011] [Indexed: 12/12/2022]
Abstract
How long organisms live is not entirely written in their genes. Recent findings reveal that epigenetic factors that regulate histone methylation, a type of chromatin modification, can affect lifespan. The reversible nature of chromatin modifications suggests that therapeutic targeting of chromatin regulators could be used to extend lifespan and healthspan. This review describes the epigenetic regulation of lifespan in diverse model organisms, focusing on the role and mode of action of chromatin regulators that affect two epigenetic marks, trimethylated lysine 4 of histone H3 (H3K4me3) and trimethylated lysine 27 of histone H3 (H3K27me3), in longevity.
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Affiliation(s)
- Shuo Han
- Department of Genetics, 300 Pasteur Drive, Stanford University, Stanford, CA 94305, USA
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