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Chen X, Wu L, Lan H, Sun R, Wen M, Ruan D, Zhang M, Wang S. Histone acetyltransferases MystA and MystB contribute to morphogenesis and aflatoxin biosynthesis by regulating acetylation in fungus Aspergillus flavus. Environ Microbiol 2021; 24:1340-1361. [PMID: 34863014 DOI: 10.1111/1462-2920.15856] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Accepted: 11/19/2021] [Indexed: 11/28/2022]
Abstract
Myst family is highly conserved histone acetyltransferases in eukaryotic cells and is known to play crucial roles in various cellular processes; however, acetylation catalysed by acetyltransferases is unclear in filamentous fungi. Here, we identified two classical nonessential Myst enzymes and analysed their functions in Aspergillus flavus, which generates aflatoxin B1, one of the most carcinogenic secondary metabolites. MystA and MystB located in nuclei and cytoplasm, and mystA could acetylate H4K16ac, while mystB acetylates H3K14ac, H3K18ac and H3K23ac. Deletion mystA resulted in decreased conidiation, increased sclerotia formation and aflatoxin production. Deletion of mystB leads to significant defects in conidiation, sclerotia formation and aflatoxin production. Additionally, double-knockout mutant (ΔmystA/mystB) display a stronger and similar defect to ΔmystB mutant, indicating that mystB plays a major role in regulating development and aflatoxin production. Both mystA and mystB play important role in crop colonization. Moreover, catalytic domain MOZ and the catalytic site E199/E243 were important for the acetyltransferase function of Myst. Notably, chromatin immunoprecipitation results indicated that mystB participated in oxidative detoxification by regulating the acetylation level of H3K14, and further regulated nsdD to affect sclerotia formation and aflatoxin production. This study provides new evidences to discover the biological functions of histone acetyltransferase in A. flavus.
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Affiliation(s)
- Xuan Chen
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, and School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Lianghuan Wu
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, and School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Huahui Lan
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, and School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Ruilin Sun
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, and School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Meifang Wen
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, and School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Danrui Ruan
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, and School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Mengjuan Zhang
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, and School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
| | - Shihua Wang
- State Key Laboratory of Ecological Pest Control for Fujian and Taiwan Crops, Key Laboratory of Pathogenic Fungi and Mycotoxins of Fujian Province, and School of Life Sciences, Fujian Agriculture and Forestry University, Fuzhou, 350002, China
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Gonzales-Zubiate FA, Okuda EK, Da Cunha JPC, Oliveira CC. Identification of karyopherins involved in the nuclear import of RNA exosome subunit Rrp6 in Saccharomyces cerevisiae. J Biol Chem 2017; 292:12267-12284. [PMID: 28539363 DOI: 10.1074/jbc.m116.772376] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2016] [Revised: 05/11/2017] [Indexed: 11/06/2022] Open
Abstract
The exosome is a conserved multiprotein complex essential for RNA processing and degradation. The nuclear exosome is a key factor for pre-rRNA processing through the activity of its catalytic subunits, Rrp6 and Rrp44. In Saccharomyces cerevisiae, Rrp6 is exclusively nuclear and has been shown to interact with exosome cofactors. With the aim of analyzing proteins associated with the nuclear exosome, in this work, we purified the complex with Rrp6-TAP, identified the co-purified proteins by mass spectrometry, and found karyopherins to be one of the major groups of proteins enriched in the samples. By investigating the biological importance of these protein interactions, we identified Srp1, Kap95, and Sxm1 as the most important karyopherins for Rrp6 nuclear import and the nuclear localization signals recognized by them. Based on the results shown here, we propose a model of multiple pathways for the transport of Rrp6 to the nucleus.
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Affiliation(s)
| | - Ellen K Okuda
- Department of Biochemistry, Institute of Chemistry, University of São Paulo, São Paulo 05508-000 SP, Brazil
| | - Julia P C Da Cunha
- Cell Cycle Laboratory, Center of Toxins, Immune Response and Cell Signaling-Center for Research on Toxins, Immune-response, and Cell Signaling (CeTICS), Butantan Institute, São Paulo 05503-900 SP, Brazil
| | - Carla Columbano Oliveira
- Department of Biochemistry, Institute of Chemistry, University of São Paulo, São Paulo 05508-000 SP, Brazil.
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Jiang JX, Aitken KJ, Sotiropolous C, Kirwan T, Panchal T, Zhang N, Pu S, Wodak S, Tolg C, Bägli DJ. Phenotypic switching induced by damaged matrix is associated with DNA methyltransferase 3A (DNMT3A) activity and nuclear localization in smooth muscle cells (SMC). PLoS One 2013; 8:e69089. [PMID: 24282625 PMCID: PMC3735580 DOI: 10.1371/journal.pone.0069089] [Citation(s) in RCA: 17] [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: 09/22/2012] [Accepted: 06/09/2013] [Indexed: 12/27/2022] Open
Abstract
Extracellular matrix changes are often crucial inciting events for fibroproliferative disease. Epigenetic changes, specifically DNA methylation, are critical factors underlying differentiated phenotypes. We examined the dependency of matrix-induced fibroproliferation and SMC phenotype on DNA methyltransferases. The cooperativity of matrix with growth factors, cell density and hypoxia was also examined. Primary rat visceral SMC of early passage (0–2) were plated on native collagen or damaged/heat-denatured collagen. Hypoxia was induced with 3% O2 (balanced 5% CO2 and 95% N2) over 48 hours. Inhibitors were applied 2–3 hours after cells were plated on matrix, or immediately before hypoxia. Cells were fixed and stained for DNMT3A and smooth muscle actin (SMA) or smooth muscle myosin heavy chain. Illumina 450 K array of CpG sites was performed on bisulfite-converted DNA from smooth muscle cells on damaged matrix vs native collagen. Matrix exquisitely regulates DNMT3A localization and expression, and influences differentiation in SMCs exposed to denatured matrix +/− hypoxia. Analysis of DNA methylation signatures showed that Matrix caused significant DNA methylation alterations in a discrete number of CpG sites proximal to genes related to SMC differentiation. Matrix has a profound effect on the regulation of SMC phenotype, which is associated with altered expression, localization of DNMTs and discrete changes DNA methylation.
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Affiliation(s)
- Jia-Xin Jiang
- Developmental and Stem Cell Biology, Hospital for Sick Children, Toronto, Ontario, Canada
- Division of Urology, Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Physiology, University of Toronto, Toronto, Ontario, Canada
| | - Karen J. Aitken
- Developmental and Stem Cell Biology, Hospital for Sick Children, Toronto, Ontario, Canada
- Division of Urology, Hospital for Sick Children, Toronto, Ontario, Canada
- * E-mail:
| | - Chris Sotiropolous
- Developmental and Stem Cell Biology, Hospital for Sick Children, Toronto, Ontario, Canada
- Division of Urology, Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Physiology, University of Toronto, Toronto, Ontario, Canada
| | - Tyler Kirwan
- Developmental and Stem Cell Biology, Hospital for Sick Children, Toronto, Ontario, Canada
- Division of Urology, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Trupti Panchal
- Cell and Systems Biology, University of Toronto, Toronto, Ontario, Canada
| | - Nicole Zhang
- Department of Physiology, University of Toronto, Toronto, Ontario, Canada
| | - Shuye Pu
- Centre for Computational Medicine, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Shoshana Wodak
- Centre for Computational Medicine, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Cornelia Tolg
- Developmental and Stem Cell Biology, Hospital for Sick Children, Toronto, Ontario, Canada
- Division of Urology, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Darius J. Bägli
- Developmental and Stem Cell Biology, Hospital for Sick Children, Toronto, Ontario, Canada
- Division of Urology, Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Physiology, University of Toronto, Toronto, Ontario, Canada
- Cell and Systems Biology, University of Toronto, Toronto, Ontario, Canada
- Institute of Medical Sciences, Department of Surgery, University of Toronto, Toronto, Ontario, Canada
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Kupke T, Di Cecco L, Müller HM, Neuner A, Adolf F, Wieland F, Nickel W, Schiebel E. Targeting of Nbp1 to the inner nuclear membrane is essential for spindle pole body duplication. EMBO J 2011; 30:3337-52. [PMID: 21785410 DOI: 10.1038/emboj.2011.242] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2011] [Accepted: 06/30/2011] [Indexed: 12/29/2022] Open
Abstract
Spindle pole bodies (SPBs), like nuclear pore complexes, are embedded in the nuclear envelope (NE) at sites of fusion of the inner and outer nuclear membranes. A network of interacting proteins is required to insert a cytoplasmic SPB precursor into the NE. A central player of this network is Nbp1 that interacts with the conserved integral membrane protein Ndc1. Here, we establish that Nbp1 is a monotopic membrane protein that is essential for SPB insertion at the inner face of the NE. In vitro and in vivo studies identified an N-terminal amphipathic α-helix of Nbp1 as a membrane-binding element, with crucial functions in SPB duplication. The karyopherin Kap123 binds to a nuclear localization sequence next to this amphipathic α-helix and prevents unspecific tethering of Nbp1 to membranes. After transport into the nucleus, Nbp1 binds to the inner nuclear membrane. These data define the targeting pathway of a SPB component and suggest that the amphipathic α-helix of Nbp1 is important for SPB insertion into the NE from within the nucleus.
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Affiliation(s)
- Thomas Kupke
- Zentrum für Molekulare Biologie der Universität Heidelberg, DKFZ-ZMBH Allianz, Heidelberg, Germany
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Chaves SR, Rosenblum JS. Efficient nuclear transport of structurally disturbed cargo: mutations in a cargo protein switch its cognate karyopherin. PLoS One 2011; 6:e16846. [PMID: 21347375 PMCID: PMC3036716 DOI: 10.1371/journal.pone.0016846] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2010] [Accepted: 01/16/2011] [Indexed: 11/18/2022] Open
Abstract
The Karyopherin (Kap) family of nuclear transport receptors enables trafficking of proteins to and from the nucleus in a precise, regulated manner. Individual members function in overlapping pathways, while simultaneously being very specific for their main cargoes. The details of this apparent contradiction and rules governing pathway preference remain to be further elucidated. S. cerevisiae Lhp1 is an abundant protein that functions as an RNA chaperone in a variety of biologically important processes. It localizes almost exclusively to the nucleus and is imported by Kap108. We show that mutation of 3 of the 275 residues in Lhp1 alters its import pathway to a Kap121-dependent process. This mutant does not retain wild-type function and is bound by several chaperones. We propose that Kap121 also acts as a chaperone, one that can act as a genetic buffer by transporting mutated proteins to the nucleus.
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Affiliation(s)
- Susana R Chaves
- Centre of Molecular and Environmental Biology, Department of Biology, University of Minho, Campus de Gualtar, Braga, Portugal.
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Chook YM, Süel KE. Nuclear import by karyopherin-βs: recognition and inhibition. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2010; 1813:1593-606. [PMID: 21029754 DOI: 10.1016/j.bbamcr.2010.10.014] [Citation(s) in RCA: 309] [Impact Index Per Article: 22.1] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Received: 07/15/2010] [Revised: 10/06/2010] [Accepted: 10/19/2010] [Indexed: 01/24/2023]
Abstract
Proteins in the karyopherin-β family mediate the majority of macromolecular transport between the nucleus and the cytoplasm. Eleven of the 19 known human karyopherin-βs and 10 of the 14S. cerevisiae karyopherin-βs mediate nuclear import through recognition of nuclear localization signals or NLSs in their cargos. This receptor-mediated process is essential to cellular viability as proteins are translated in the cytoplasm but many have functional roles in the nucleus. Many known karyopherin-β-cargo interactions were discovered through studies of the individual cargos rather than the karyopherins, and this information is thus widely scattered in the literature. We consolidate information about cargos that are directly recognized by import-karyopherin-βs and review common characteristics or lack thereof among cargos of different import pathways. Knowledge of karyopherin-β-cargo interactions is also critical for the development of nuclear import inhibitors and the understanding of their mechanisms of inhibition. This article is part of a Special Issue entitled: Regulation of Signaling and Cellular Fate through Modulation of Nuclear Protein Import.
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Affiliation(s)
- Yuh Min Chook
- Department of Pharmacology, University of Texas Southerwestern Medical Center, Dallas, TX 75206, USA.
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Taberner FJ, Igual JC. Yeast karyopherin Kap95 is required for cell cycle progression at Start. BMC Cell Biol 2010; 11:47. [PMID: 20587033 PMCID: PMC2904269 DOI: 10.1186/1471-2121-11-47] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2009] [Accepted: 06/29/2010] [Indexed: 11/18/2022] Open
Abstract
Background The control of the subcellular localization of cell cycle regulators has emerged as a crucial mechanism in cell division regulation. The active transport of proteins between the nucleus and the cytoplasm is mediated by the transport receptors of the β-karyopherin family. In this work we characterized the terminal phenotype of a mutant strain in β-karyopherin Kap95, a component of the classical nuclear import pathway. Results When KAP95 was inactivated, most cells arrested at the G2/M phase of the cell cycle, which is in agreement with the results observed in mutants in the other components of this pathway. However, a number of cells accumulate at G1, suggesting a novel role of Kap95 and the classical import pathway at Start. We investigated the localization of Start transcription factors. It is known that Swi6 contains a classical NLS that interacts with importin α. Here we show that the in vivo nuclear import of Swi6 depends on Kap95. For Swi4, we identified a functional NLS between amino acids 371 and 376 that is sufficient and necessary for Swi4 to enter the nucleus. The nuclear import driven by this NLS is mediated by karyopherins Kap95 and Srp1. Inactivation of Kap95 also produces a dramatic change in the localization of Mbp1 since the protein is mainly detected in the cytoplasm. Two functionally redundant Kap95- and Srp1-dependent NLSs were identified in Mbp1 between amino acids 27-30 and 166-181. Nuclear accumulation was not completely abolished in a kap95 mutant or in the Mbp1 mutated in the two NLSs, suggesting that alternative pathways might contribute to the Mbp1 nuclear import to a lesser extent. Conclusions Kap95 plays an essential role at the initiation of the cell cycle by driving the nuclear import of Swi4, Swi6 and Mbp1, the three transcription factors responsible for the gene expression at Start. This transport depends on the specific nuclear localization signals present in cargo proteins.
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Affiliation(s)
- Francisco José Taberner
- Departament de Bioquímica i Biologia Molecular, Universitat de València, Dr. Moliner 50, 46100 Burjassot (Valencia), Spain
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Martínez-Bono B, Quilis I, Zalve E, Igual JC. Yeast karyopherins Kap123 and Kap95 are related to the function of the cell integrity pathway. FEMS Yeast Res 2009; 10:28-37. [PMID: 19930464 DOI: 10.1111/j.1567-1364.2009.00591.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
The characterization of mutant strains in the gene encoding karyopherin Kap123 has revealed several morphogenetic defects. Inactivation of KAP123 caused alterations in the actin cytoskeleton, resulting in hyperpolarization and resistance to the actin polymerization inhibitor latrunculin B. In fact, the level of actin filaments is increased in kap123 mutant cells. In addition to the defect in actin cytoskeleton, the kap123 mutant cells showed a weakened cell wall, cell lysis and a growth defect in either the presence of sodium dodecyl sulfate or at high temperatures, which is alleviated by osmotic stabilizers. These defects in cell integrity and the actin cytoskeleton suggested a relationship with the protein kinase C (PKC) cell integrity pathway. Slt2, the mitogen-activated protein kinase of the PKC cell integrity pathway, is constitutively activated in the absence of Kap123, which is consistent with the existence of cell integrity defects. Analysis of the subcellular localization of nuclear proteins involved in cell wall gene expression indicated that the localization of the Slt2 kinase and the transcription factors Rlm1, Swi6 and Paf1 was not affected by Kap123. Finally, we identified karyopherin Kap95 as the transport factor responsible for the nuclear import of Slt2 and Rlm1.
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Affiliation(s)
- Bárbara Martínez-Bono
- Departament de Bioquímica i Biologia Molecular, Facultat de Ciències Biològiques, Universitat de València, Valencia, Spain
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Etxebeste O, Markina-Iñarrairaegui A, Garzia A, Herrero-García E, Ugalde U, Espeso EA. KapI, a non-essential member of the Pse1p/Imp5 karyopherin family, controls colonial and asexual development in Aspergillus nidulans. MICROBIOLOGY-SGM 2009; 155:3934-3945. [PMID: 19729403 DOI: 10.1099/mic.0.032615-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Asexual development in the filamentous fungus Aspergillus nidulans is governed by the timely expression and cellular localization of multiple transcription factors. Hence, factors mediating import and export across the nuclear pore complexes (karyopherins) are expected to play a key role in coordinating the developmental programme. Here we characterize KapI, a putative homologue of the Saccharomyces cerevisiae Kap121/Pse1p karyopherin. KapI is a non-essential importin-beta-like protein located in the nucleus during vegetative growth and conidiophore development. The DeltakapI phenotype is aconidial with many aerial hyphae. This phenotype can be suppressed under abiotic stress. In this regard, it resembles that of the null allele of the bZIP transcription factor FlbB. However a DeltaflbB; DeltakapI double mutant exhibited an additive phenotype with totally impaired conidiation, unresponsive to abiotic stress. In contrast to DeltaflbB, the null kapI mutant is not a fluffy-low-bristle expression mutant. Taken together the findings indicate that KapI is required during asexual development, mediating the nuclear transport of factors acting in a different pathway(s) from those involving the upstream developmental activators.
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Affiliation(s)
- Oier Etxebeste
- CIC Nanogune, Mikeletegi Pasealekua 56, San Sebastian, Spain.,Department of Cellular and Molecular Medicine. Centro de Investigaciones Biológicas (CSIC), Ramiro de Maeztu, 9, 28040 Madrid, Spain
| | - Ane Markina-Iñarrairaegui
- Department of Cellular and Molecular Medicine. Centro de Investigaciones Biológicas (CSIC), Ramiro de Maeztu, 9, 28040 Madrid, Spain
| | - Aitor Garzia
- Department of Applied Chemistry, Faculty of Chemistry, University of The Basque Country, 20018 San Sebastian, Spain
| | - Erika Herrero-García
- Department of Cellular and Molecular Medicine. Centro de Investigaciones Biológicas (CSIC), Ramiro de Maeztu, 9, 28040 Madrid, Spain
| | - Unai Ugalde
- Department of Applied Chemistry, Faculty of Chemistry, University of The Basque Country, 20018 San Sebastian, Spain
| | - Eduardo A Espeso
- Department of Cellular and Molecular Medicine. Centro de Investigaciones Biológicas (CSIC), Ramiro de Maeztu, 9, 28040 Madrid, Spain
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Schulze JM, Wang AY, Kobor MS. YEATS domain proteins: a diverse family with many links to chromatin modification and transcriptionThis paper is one of a selection of papers published in this Special Issue, entitled CSBMCB’s 51st Annual Meeting – Epigenetics and Chromatin Dynamics, and has undergone the Journal’s usual peer review process. Biochem Cell Biol 2009; 87:65-75. [DOI: 10.1139/o08-111] [Citation(s) in RCA: 96] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Chromatin modifications play crucial roles in various biological processes. An increasing number of conserved protein domains, often found in multisubunit protein complexes, are involved in establishing and recognizing different chromatin modifications. The YEATS domain is one of these domains, and its role in chromatin modifications and transcription is just beginning to be appreciated. The YEATS domain family of proteins, conserved from yeast to human, contains over 100 members in more than 70 eukaryotic species. Yaf9, Taf14, and Sas5 are the only YEATS domain proteins in Saccharomyces cerevisiae. Human YEATS domain family members, such as GAS41, ENL, and AF9, have a strong link to cancer. GAS41 is amplified in glioblastomas and astrocytomas; ENL and AF9 are among the most frequent translocation partners of the mixed lineage leukemia (MLL) gene. This review will focus on the best characterized YEATS proteins, discuss their diverse roles, and reflect potential functions of the YEATS domain.
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Affiliation(s)
- Julia M. Schulze
- Centre for Molecular Medicine and Therapeutics, Child and Family Research Institute, Department of Medical Genetics, University of British Columbia, Vancouver, BC V5Z 4H4, Canada
| | - Alice Y. Wang
- Centre for Molecular Medicine and Therapeutics, Child and Family Research Institute, Department of Medical Genetics, University of British Columbia, Vancouver, BC V5Z 4H4, Canada
| | - Michael S. Kobor
- Centre for Molecular Medicine and Therapeutics, Child and Family Research Institute, Department of Medical Genetics, University of British Columbia, Vancouver, BC V5Z 4H4, Canada
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Pillus L. MYSTs mark chromatin for chromosomal functions. Curr Opin Cell Biol 2008; 20:326-33. [PMID: 18511253 DOI: 10.1016/j.ceb.2008.04.009] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2008] [Revised: 04/16/2008] [Accepted: 04/21/2008] [Indexed: 12/01/2022]
Abstract
The MYST family of lysine acetyltransferases has been intensely studied because of its broad conservation and biological significance. In humans, there are multiple correlations between the enzymes and development and disease. In model organisms, genetic and biochemical studies have been particularly productive because of mechanistic insights they provide in defining substrate specificity, the complexes through which the enzymes function, and the sites of their activity within the genome. Established and emerging data from yeast reveal roles for the three MYST enzymes in diverse chromosomal functions. In particular, recent studies help explain how MYST complexes coordinate with other modifiers, the histone variant H2A.Z, and remodeling complexes to demarcate silent and active chromosomal domains, facilitate transcription, and enable repair of DNA damage.
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Affiliation(s)
- Lorraine Pillus
- University of California, San Diego, Division of Biological Sciences, Molecular Biology and Moores Cancer Center, 9500 Gilman Drive, La Jolla, CA 92093-0347, United States.
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Shia WJ, Li B, Workman JL. SAS-mediated acetylation of histone H4 Lys 16 is required for H2A.Z incorporation at subtelomeric regions in Saccharomyces cerevisiae. Genes Dev 2006; 20:2507-12. [PMID: 16980580 PMCID: PMC1578674 DOI: 10.1101/gad.1439206] [Citation(s) in RCA: 89] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The yeast SAS (Something About Silencing) complex and the histone variant H2A.Z have both previously been linked to an antisilencing function at the subtelomeric regions. SAS is an H4 Lys 16-specific histone acetyltransferase complex. Here we demonstrate that the H4 Lys 16 acetylation by SAS is required for efficient H2A.Z incorporation near telomeres. The presence of H4 Lys 16 acetylation and H2A.Z synergistically prevent the ectopic propagation of heterochromatin. Overall, our data suggest a novel antisilencing mechanism near telomeres.
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Affiliation(s)
- Wei-Jong Shia
- Stowers Institute for Medical Research, Kansas City, Missouri 64110, USA
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, Pennsylvania 16802, USA
| | - Bing Li
- Stowers Institute for Medical Research, Kansas City, Missouri 64110, USA
| | - Jerry L. Workman
- Stowers Institute for Medical Research, Kansas City, Missouri 64110, USA
- Corresponding author.E-MAIL ; FAX (816) 926-4692
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Bakhrat A, Baranes K, Krichevsky O, Rom I, Schlenstedt G, Pietrokovski S, Raveh D. Nuclear import of ho endonuclease utilizes two nuclear localization signals and four importins of the ribosomal import system. J Biol Chem 2006; 281:12218-26. [PMID: 16507575 DOI: 10.1074/jbc.m600238200] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Activity of Ho, the yeast mating switch endonuclease, is restricted to a narrow time window of the cell cycle. Ho is unstable and despite being a nuclear protein is exported to the cytoplasm for proteasomal degradation. We report here the molecular basis for the highly efficient nuclear import of Ho and the relation between its short half-life and passage through the nucleus. The Ho nuclear import machinery is functionally redundant, being based on two bipartite nuclear localization signals, recognized by four importins of the ribosomal import system. Ho degradation is regulated by the DNA damage response and Ho retained in the cytoplasm is stabilized, implying that Ho acquires its crucial degradation signals in the nucleus. Ho arose by domestication of a fungal VMA1 intein. A comparison of the primary sequences of Ho and fungal VMA1 inteins shows that the Ho nuclear localization signals are highly conserved in all Ho proteins, but are absent from VMA1 inteins. Thus adoption of a highly efficient import strategy occurred very early in the evolution of Ho. This may have been a crucial factor in establishment of homothallism in yeast, and a key event in the rise of the Saccharomyces sensu stricto.
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Affiliation(s)
- Anya Bakhrat
- Department of Life Sciences, Ben Gurion University of the Negev, P. O. Box 653, 84105 Beersheba, Israel
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Current awareness on yeast. Yeast 2005. [DOI: 10.1002/yea.1169] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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