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Giuliano CJ, Wei KJ, Harling FM, Waldman BS, Farringer MA, Boydston EA, Lan TCT, Thomas RW, Herneisen AL, Sanderlin AG, Coppens I, Dvorin JD, Lourido S. CRISPR-based functional profiling of the Toxoplasma gondii genome during acute murine infection. Nat Microbiol 2024; 9:2323-2343. [PMID: 38977907 DOI: 10.1038/s41564-024-01754-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2024] [Accepted: 06/07/2024] [Indexed: 07/10/2024]
Abstract
Examining host-pathogen interactions in animals can capture aspects of infection that are obscured in cell culture. Using CRISPR-based screens, we functionally profile the entire genome of the apicomplexan parasite Toxoplasma gondii during murine infection. Barcoded gRNAs enabled bottleneck detection and mapping of population structures within parasite lineages. Over 300 genes with previously unknown roles in infection were found to modulate parasite fitness in mice. Candidates span multiple axes of host-parasite interaction. Rhoptry Apical Surface Protein 1 was characterized as a mediator of host-cell tropism that facilitates repeated invasion attempts. GTP cyclohydrolase I was also required for fitness in mice and druggable through a repurposed compound, 2,4-diamino-6-hydroxypyrimidine. This compound synergized with pyrimethamine against T. gondii and malaria-causing Plasmodium falciparum parasites. This work represents a complete survey of an apicomplexan genome during infection of an animal host and points to novel interfaces of host-parasite interaction.
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Affiliation(s)
| | - Kenneth J Wei
- Whitehead Institute, Cambridge, MA, USA
- Biology Department, MIT, Cambridge, MA, USA
| | | | - Benjamin S Waldman
- Whitehead Institute, Cambridge, MA, USA
- Biology Department, MIT, Cambridge, MA, USA
| | - Madeline A Farringer
- Division of Infectious Diseases, Boston Children's Hospital, Boston, MA, USA
- Biological Sciences in Public Health, Harvard T.H. Chan School of Public Health, Boston, MA, USA
| | | | | | - Raina W Thomas
- Whitehead Institute, Cambridge, MA, USA
- Biology Department, MIT, Cambridge, MA, USA
| | - Alice L Herneisen
- Whitehead Institute, Cambridge, MA, USA
- Biology Department, MIT, Cambridge, MA, USA
| | | | - Isabelle Coppens
- Department of Molecular Microbiology and Immunology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD, USA
| | - Jeffrey D Dvorin
- Division of Infectious Diseases, Boston Children's Hospital, Boston, MA, USA
- Department of Pediatrics, Harvard Medical School, Boston, MA, USA
| | - Sebastian Lourido
- Whitehead Institute, Cambridge, MA, USA.
- Biology Department, MIT, Cambridge, MA, USA.
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Kalamuddin M, Shakri AR, Wang C, Min H, Li X, Cui L, Miao J. MYST regulates DNA repair and forms a NuA4-like complex in the malaria parasite Plasmodium falciparum. mSphere 2024; 9:e0014024. [PMID: 38564734 PMCID: PMC11036802 DOI: 10.1128/msphere.00140-24] [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: 02/21/2024] [Accepted: 03/13/2024] [Indexed: 04/04/2024] Open
Abstract
Histone lysine acetyltransferase MYST-associated NuA4 complex is conserved from yeast to humans and plays key roles in cell cycle regulation, gene transcription, and DNA replication/repair. Here, we identified a Plasmodium falciparum MYST-associated complex, PfNuA4, which contains 11 of the 13 conserved NuA4 subunits. Reciprocal pulldowns using PfEAF2, a shared component between the NuA4 and SWR1 complexes, not only confirmed the PfNuA4 complex but also identified the PfSWR1 complex, a histone remodeling complex, although their identities are low compared to the homologs in yeast or humans. Notably, both H2A.Z/H2B.Z were associated with the PfSWR1 complex, indicating that this complex is involved in the deposition of H2A.Z/H2B.Z, the variant histone pair that is enriched in the activated promoters. Overexpression of PfMYST resulted in earlier expression of genes involved in cell cycle regulation, DNA replication, and merozoite invasion, and upregulation of the genes related to antigenic variation and DNA repair. Consistently, PfMYST overexpression led to high basal phosphorylated PfH2A (γ-PfH2A), the mark of DNA double-strand breaks, and conferred protection against genotoxic agent methyl methanesulfonate (MMS), X-rays, and artemisinin, the first-line antimalarial drug. In contrast, the knockdown of PfMYST caused a delayed parasite recovery upon MMS treatment. MMS induced the gradual disappearance of PfMYST in the cytoplasm and concomitant accumulation of PfMYST in the nucleus, suggesting cytoplasm-nucleus shuttling of PfMYST. Meanwhile, PfMYST colocalized with the γ-PfH2A, indicating PfMYST was recruited to the DNA damage sites. Collectively, PfMYST plays critical roles in cell cycle regulation, gene transcription, and DNA replication/DNA repair in this low-branching parasitic protist.IMPORTANCEUnderstanding gene regulation and DNA repair in malaria parasites is critical for identifying targets for antimalarials. This study found PfNuA4, a PfMYST-associated, histone modifier complex, and PfSWR1, a chromatin remodeling complex in malaria parasite Plasmodium falciparum. These complexes are divergent due to the low identities compared to their homologs from yeast and humans. Furthermore, overexpression of PfMYST resulted in substantial transcriptomic changes, indicating that PfMYST is involved in regulating the cell cycle, antigenic variation, and DNA replication/repair. Consistently, PfMYST was found to protect against DNA damage caused by the genotoxic agent methyl methanesulfonate, X-rays, and artemisinin, the first-line antimalarial drug. Additionally, DNA damage led to the relocation of cytoplasmic PfMYST to the nucleus and colocalization of PfMYST with γ-PfH2A, the mark of DNA damage. In summary, this study demonstrated that the PfMYST complex has critical functions in regulating cell cycle, antigenic variation, and DNA replication/DNA repair in P. falciparum.
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Affiliation(s)
- Mohammad Kalamuddin
- Department of Internal Medicine, University of South Florida, Morsani College of Medicine, Tampa, Florida, USA
| | - Ahmad Rushdi Shakri
- Department of Internal Medicine, University of South Florida, Morsani College of Medicine, Tampa, Florida, USA
| | - Chengqi Wang
- Center for Global Health and Infectious Diseases Research, College of Public Health, University of South Florida, Tampa, Florida, USA
| | - Hui Min
- Department of Internal Medicine, University of South Florida, Morsani College of Medicine, Tampa, Florida, USA
| | - Xiaolian Li
- Department of Internal Medicine, University of South Florida, Morsani College of Medicine, Tampa, Florida, USA
| | - Liwang Cui
- Department of Internal Medicine, University of South Florida, Morsani College of Medicine, Tampa, Florida, USA
- Center for Global Health and Infectious Diseases Research, College of Public Health, University of South Florida, Tampa, Florida, USA
| | - Jun Miao
- Department of Internal Medicine, University of South Florida, Morsani College of Medicine, Tampa, Florida, USA
- Center for Global Health and Infectious Diseases Research, College of Public Health, University of South Florida, Tampa, Florida, USA
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Giuliano CJ, Wei KJ, Harling FM, Waldman BS, Farringer MA, Boydston EA, Lan TCT, Thomas RW, Herneisen AL, Sanderlin AG, Coppens I, Dvorin JD, Lourido S. Functional profiling of the Toxoplasma genome during acute mouse infection. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.03.05.531216. [PMID: 36945434 PMCID: PMC10028831 DOI: 10.1101/2023.03.05.531216] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/12/2023]
Abstract
Within a host, pathogens encounter a diverse and changing landscape of cell types, nutrients, and immune responses. Examining host-pathogen interactions in animal models can therefore reveal aspects of infection absent from cell culture. We use CRISPR-based screens to functionally profile the entire genome of the model apicomplexan parasite Toxoplasma gondii during mouse infection. Barcoded gRNAs were used to track mutant parasite lineages, enabling detection of bottlenecks and mapping of population structures. We uncovered over 300 genes that modulate parasite fitness in mice with previously unknown roles in infection. These candidates span multiple axes of host-parasite interaction, including determinants of tropism, host organelle remodeling, and metabolic rewiring. We mechanistically characterized three novel candidates, including GTP cyclohydrolase I, against which a small-molecule inhibitor could be repurposed as an antiparasitic compound. This compound exhibited antiparasitic activity against T. gondii and Plasmodium falciparum, the most lethal agent of malaria. Taken together, we present the first complete survey of an apicomplexan genome during infection of an animal host, and point to novel interfaces of host-parasite interaction that may offer new avenues for treatment.
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Affiliation(s)
| | - Kenneth J. Wei
- Whitehead Institute, Cambridge, MA
- Biology Department, MIT, Cambridge, MA
| | - Faye M. Harling
- Whitehead Institute, Cambridge, MA
- Biology Department, MIT, Cambridge, MA
| | | | - Madeline A. Farringer
- Division of Infectious Diseases, Boston Children’s Hospital, Boston, Massachusetts, USA
- Biological Sciences in Public Health, Harvard T.H. Chan School of Public Health, Boston, Massachusetts, USA
| | | | | | - Raina W. Thomas
- Whitehead Institute, Cambridge, MA
- Biology Department, MIT, Cambridge, MA
| | - Alice L. Herneisen
- Whitehead Institute, Cambridge, MA
- Biology Department, MIT, Cambridge, MA
| | | | - Isabelle Coppens
- Department of Molecular Microbiology and Immunology, Johns Hopkins University Bloomberg School of Public Health, Baltimore, MD
| | - Jeffrey D. Dvorin
- Division of Infectious Diseases, Boston Children’s Hospital, Boston, Massachusetts, USA
- Department of Pediatrics, Harvard Medical School, Boston, Massachusetts, USA
| | - Sebastian Lourido
- Whitehead Institute, Cambridge, MA
- Biology Department, MIT, Cambridge, MA
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4
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Role of PfMYST in DNA replication in Plasmodium falciparum. Exp Parasitol 2022; 242:108396. [DOI: 10.1016/j.exppara.2022.108396] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2022] [Revised: 09/20/2022] [Accepted: 09/27/2022] [Indexed: 11/23/2022]
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Abstract
Plasmodium falciparum is the deadliest human parasite that causes malaria when it reaches the bloodstream and begins proliferating inside red blood cells, where the parasites are particularly prone to DNA damage. The molecular mechanisms that allow these pathogens to maintain their genome integrity under such conditions are also the driving force for acquiring genome plasticity that enables them to create antigenic variation and become resistant to essentially all available drugs. Plasmodium falciparum parasites proliferate within circulating red blood cells and are responsible for the deadliest form of human malaria. These parasites are exposed to numerous intrinsic and external sources that could cause DNA damage; therefore, they have evolved efficient mechanisms to protect their genome integrity and allow them to proliferate under such conditions. In higher eukaryotes, double-strand breaks rapidly lead to phosphorylation of the core histone variant H2A.X, which marks the site of damaged DNA. We show that in P. falciparum that lacks the H2A.X variant, the canonical P. falciparum H2A (PfH2A) is phosphorylated on serine 121 upon exposure to sources of DNA damage. We further demonstrate that phosphorylated PfH2A is recruited to foci of damaged chromatin shortly after exposure to sources of damage, while the nonphosphorylated PfH2A remains spread throughout the nucleoplasm. In addition, we found that PfH2A phosphorylation is dynamic and that over time, as the parasite activates the repair machinery, this phosphorylation is removed. Finally, we demonstrate that these phosphorylation dynamics could be used to establish a novel and direct DNA repair assay in P. falciparum. IMPORTANCEPlasmodium falciparum is the deadliest human parasite that causes malaria when it reaches the bloodstream and begins proliferating inside red blood cells, where the parasites are particularly prone to DNA damage. The molecular mechanisms that allow these pathogens to maintain their genome integrity under such conditions are also the driving force for acquiring genome plasticity that enables them to create antigenic variation and become resistant to essentially all available drugs. However, mechanisms of DNA damage response and repair have not been extensively studied for these parasites. The paper addresses our recent discovery that P. falciparum that lacks the histone variant H2A.X phosphorylates its canonical core histone PfH2A in response to exposure to DNA damage. The process of DNA repair in Plasmodium was mostly studied indirectly. Our findings enabled us to establish a direct DNA repair assay for P. falciparum similar to assays that are widely used in model organisms.
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Khan P, Siddiqui JA, Maurya SK, Lakshmanan I, Jain M, Ganti AK, Salgia R, Batra SK, Nasser MW. Epigenetic landscape of small cell lung cancer: small image of a giant recalcitrant disease. Semin Cancer Biol 2020; 83:57-76. [PMID: 33220460 PMCID: PMC8218609 DOI: 10.1016/j.semcancer.2020.11.006] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Revised: 11/10/2020] [Accepted: 11/11/2020] [Indexed: 12/12/2022]
Abstract
Small cell lung cancer (SCLC) is a particular subtype of lung cancer with high mortality. Recent advances in understanding SCLC genomics and breakthroughs of immunotherapy have substantially expanded existing knowledge and treatment modalities. However, challenges associated with SCLC remain enigmatic and elusive. Most of the conventional drug discovery approaches targeting altered signaling pathways in SCLC end up in the 'grave-yard of drug discovery', which mandates exploring novel approaches beyond inhibiting cell signaling pathways. Epigenetic modifications have long been documented as the key contributors to the tumorigenesis of almost all types of cancer, including SCLC. The last decade witnessed an exponential increase in our understanding of epigenetic modifications for SCLC. The present review highlights the central role of epigenetic regulations in acquiring neoplastic phenotype, metastasis, aggressiveness, resistance to chemotherapy, and immunotherapeutic approaches of SCLC. Different types of epigenetic modifications (DNA/histone methylation or acetylation) that can serve as predictive biomarkers for prognostication, treatment stratification, neuroendocrine lineage determination, and development of potential SCLC therapies are also discussed. We also review the utility of epigenetic targets/epidrugs in combination with first-line chemotherapy and immunotherapy that are currently under investigation in preclinical and clinical studies. Altogether, the information presents the inclusive landscape of SCLC epigenetics and epidrugs that will help to improve SCLC outcomes.
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Affiliation(s)
- Parvez Khan
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE-68198, USA
| | - Jawed Akhtar Siddiqui
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE-68198, USA
| | - Shailendra Kumar Maurya
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE-68198, USA
| | - Imayavaramban Lakshmanan
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE-68198, USA
| | - Maneesh Jain
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE-68198, USA; Fred and Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Apar Kishor Ganti
- Fred and Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, NE 68198, USA; Division of Oncology-Hematology, Department of Internal Medicine, VA-Nebraska Western Iowa Health Care System, Omaha, NE, 68105, USA; Division of Oncology-Hematology, Department of Internal Medicine, University of Nebraska Medical Center, Omaha, NE, 68198, USA
| | - Ravi Salgia
- Department of Medical Oncology and Therapeutics Research, City of Hope Comprehensive Cancer Center and Beckman Research Institute, Duarte 91010, CA, USA
| | - Surinder Kumar Batra
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE-68198, USA; Fred and Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, NE 68198, USA; Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Mohd Wasim Nasser
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE-68198, USA; Fred and Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, NE 68198, USA.
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Angel SO, Vanagas L, Ruiz DM, Cristaldi C, Saldarriaga Cartagena AM, Sullivan WJ. Emerging Therapeutic Targets Against Toxoplasma gondii: Update on DNA Repair Response Inhibitors and Genotoxic Drugs. Front Cell Infect Microbiol 2020; 10:289. [PMID: 32656097 PMCID: PMC7325978 DOI: 10.3389/fcimb.2020.00289] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Accepted: 05/15/2020] [Indexed: 12/11/2022] Open
Abstract
Toxoplasma gondii is the causative agent of toxoplasmosis in animals and humans. This infection is transmitted to humans through oocysts released in the feces of the felines into the environment or by ingestion of undercooked meat. This implies that toxoplasmosis is a zoonotic disease and T. gondii is a foodborne pathogen. In addition, chronic toxoplasmosis in goats and sheep is the cause of recurrent abortions with economic losses in the sector. It is also a health problem in pets such as cats and dogs. Although there are therapies against this infection in its acute stage, they are not able to permanently eliminate the parasite and sometimes they are not well tolerated. To develop better, safer drugs, we need to elucidate key aspects of the biology of T. gondii. In this review, we will discuss the importance of the homologous recombination repair (HRR) pathway in the parasite's lytic cycle and how components of these processes can be potential molecular targets for new drug development programs. In that sense, the effect of different DNA damage agents or HHR inhibitors on the growth and replication of T. gondii will be described. Multitarget drugs that were either associated with other targets or were part of general screenings are included in the list, providing a thorough revision of the drugs that can be tested in other scenarios.
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Affiliation(s)
- Sergio O Angel
- Laboratorio de Parasitología Molecular, Instituto Tecnológico Chascomús (INTECH), Consejo Nacional de Investigaciones Científicas (CONICET)-Universidad Nacional General San Martin (UNSAM), Chascomús, Argentina
| | - Laura Vanagas
- Laboratorio de Parasitología Molecular, Instituto Tecnológico Chascomús (INTECH), Consejo Nacional de Investigaciones Científicas (CONICET)-Universidad Nacional General San Martin (UNSAM), Chascomús, Argentina
| | - Diego M Ruiz
- Laboratorio de Parasitología Molecular, Instituto Tecnológico Chascomús (INTECH), Consejo Nacional de Investigaciones Científicas (CONICET)-Universidad Nacional General San Martin (UNSAM), Chascomús, Argentina
| | - Constanza Cristaldi
- Laboratorio de Parasitología Molecular, Instituto Tecnológico Chascomús (INTECH), Consejo Nacional de Investigaciones Científicas (CONICET)-Universidad Nacional General San Martin (UNSAM), Chascomús, Argentina
| | - Ana M Saldarriaga Cartagena
- Laboratorio de Parasitología Molecular, Instituto Tecnológico Chascomús (INTECH), Consejo Nacional de Investigaciones Científicas (CONICET)-Universidad Nacional General San Martin (UNSAM), Chascomús, Argentina
| | - William J Sullivan
- Pharmacology and Toxicology, Indiana University School of Medicine, Indianapolis, IN, United States.,Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, IN, United States
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8
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Yin D, Jiang N, Zhang Y, Wang D, Sang X, Feng Y, Chen R, Wang X, Yang N, Chen Q. Global Lysine Crotonylation and 2-Hydroxyisobutyrylation in Phenotypically Different Toxoplasma gondii Parasites. Mol Cell Proteomics 2019; 18:2207-2224. [PMID: 31488510 PMCID: PMC6823851 DOI: 10.1074/mcp.ra119.001611] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2019] [Revised: 09/04/2019] [Indexed: 12/23/2022] Open
Abstract
Toxoplasma gondii is a unicellular protozoan parasite of the phylum Apicomplexa. The parasite repeatedly goes through a cycle of invasion, division and induction of host cell rupture, which is an obligatory process for proliferation inside warm-blooded animals. It is known that the biology of the parasite is controlled by a variety of mechanisms ranging from genomic to epigenetic to transcriptional regulation. In this study, we investigated the global protein posttranslational lysine crotonylation and 2-hydroxyisobutyrylation of two T. gondii strains, RH and ME49, which represent distinct phenotypes for proliferation and pathogenicity in the host. Proteins with differential expression and modification patterns associated with parasite phenotypes were identified. Many proteins in T. gondii were crotonylated and 2-hydroxyisobutyrylated, and they were localized in diverse subcellular compartments involved in a wide variety of cellular functions such as motility, host invasion, metabolism and epigenetic gene regulation. These findings suggest that lysine crotonylation and 2-hydroxyisobutyrylation are ubiquitous throughout the T. gondii proteome, regulating critical functions of the modified proteins. These data provide a basis for identifying important proteins associated with parasite development and pathogenicity.
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Affiliation(s)
- Deqi Yin
- Key Laoratory of Animal Infectious Diseases in Northeast China, Ministry of Education, Key Laboratory of Zoonosis, Shenyang Agricultural University, 120 Dongling Road, Shenyang 110166, China
| | - Ning Jiang
- Key Laoratory of Animal Infectious Diseases in Northeast China, Ministry of Education, Key Laboratory of Zoonosis, Shenyang Agricultural University, 120 Dongling Road, Shenyang 110166, China
| | - Yue Zhang
- Key Laoratory of Animal Infectious Diseases in Northeast China, Ministry of Education, Key Laboratory of Zoonosis, Shenyang Agricultural University, 120 Dongling Road, Shenyang 110166, China
| | - Dawei Wang
- Key Laoratory of Animal Infectious Diseases in Northeast China, Ministry of Education, Key Laboratory of Zoonosis, Shenyang Agricultural University, 120 Dongling Road, Shenyang 110166, China
| | - Xiaoyu Sang
- Key Laoratory of Animal Infectious Diseases in Northeast China, Ministry of Education, Key Laboratory of Zoonosis, Shenyang Agricultural University, 120 Dongling Road, Shenyang 110166, China
| | - Ying Feng
- Key Laoratory of Animal Infectious Diseases in Northeast China, Ministry of Education, Key Laboratory of Zoonosis, Shenyang Agricultural University, 120 Dongling Road, Shenyang 110166, China
| | - Rang Chen
- Key Laoratory of Animal Infectious Diseases in Northeast China, Ministry of Education, Key Laboratory of Zoonosis, Shenyang Agricultural University, 120 Dongling Road, Shenyang 110166, China
| | - Xinyi Wang
- College of Basic Education, Shenyang Agricultural University, 120 Dongling Road, Shenyang 110166, China
| | - Na Yang
- Key Laoratory of Animal Infectious Diseases in Northeast China, Ministry of Education, Key Laboratory of Zoonosis, Shenyang Agricultural University, 120 Dongling Road, Shenyang 110166, China
| | - Qijun Chen
- Key Laoratory of Animal Infectious Diseases in Northeast China, Ministry of Education, Key Laboratory of Zoonosis, Shenyang Agricultural University, 120 Dongling Road, Shenyang 110166, China.
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Supplementing Genistein for Breeder Hens Alters the Fatty Acid Metabolism and Growth Performance of Offsprings by Epigenetic Modification. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2019; 2019:9214209. [PMID: 31049141 PMCID: PMC6458848 DOI: 10.1155/2019/9214209] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/14/2018] [Revised: 12/05/2018] [Accepted: 02/04/2019] [Indexed: 12/30/2022]
Abstract
The experiment was designed to clarify the effect and molecular mechanism of maternal genistein (GEN) on the lipid metabolism and developmental growth of offspring chicks. Laying broiler breeder (LBB) hens were supplemented with 40 mg/kg genistein (GEN), while the control group was fed with the low-soybean meal diet. The offspring chicks were grouped according to the mother generation with 8 replicates each. Hepatic transcriptome data revealed 3915 differentially expressed genes (DEGs, P adjusted < 0.05, fold change > 1.5 or fold change < 0.67) between chicks in the two groups. Maternal GEN activated the GH-IGF1-PI3K/Akt signaling pathway, which promoted the developmental processes and cellular amino acid metabolic processes, as well as inhibited the apoptotic process. GEN treatment significantly increased the weight gain, breast muscle percentage, and liver index in chicks. PANTHER clustering analysis suggested that maternal GEN enhanced the antioxidant activity of chicks by the upregulation of gene (SOD3, MT1, and MT4) expression. Accordingly, the activities of T-AOC and T-SOD in the liver were increased after GEN treatment. The overrepresentation tests revealed that maternal GEN influenced the glycolysis, unsaturated fatty acid biosynthesis, acyl-coenzyme A metabolism, lipid transport, and cholesterol metabolism in the chick livers. Hepatic cholesterol and long-chain fatty acid were significantly decreased after GEN treatment. However, the level of arachidonic acid was higher in the livers of the GEN-treated group compared with the CON group. Moreover, GEN treatment enhanced fatty acid β-oxidation and upregulated PPARδ expression in the chick liver. ChIP-qPCR analysis indicated that maternal GEN might induce histone H3-K36 trimethylation in the promoter region of PPARδ gene (PPARD) through Iws1, methyltransferases. It also induced histone H4-K12 acetylation at the PPARD promoter through MYST2, which activated the PPAR signaling pathways in the chick livers. In summary, supplementing LBB hens with GEN can alter lipid metabolism in the offspring chicks through epigenetic modification and improve the antioxidative capability as well as growth performance.
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10
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Munera López J, Ganuza A, Bogado SS, Muñoz D, Ruiz DM, Sullivan WJ, Vanagas L, Angel SO. Evaluation of ATM Kinase Inhibitor KU-55933 as Potential Anti- Toxoplasma gondii Agent. Front Cell Infect Microbiol 2019; 9:26. [PMID: 30815397 PMCID: PMC6381018 DOI: 10.3389/fcimb.2019.00026] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2018] [Accepted: 01/25/2019] [Indexed: 01/01/2023] Open
Abstract
Toxoplasma gondii is an apicomplexan protozoan parasite with a complex life cycle composed of multiple stages that infect mammals and birds. Tachyzoites rapidly replicate within host cells to produce acute infection during which the parasite disseminates to tissues and organs. Highly replicative cells are subject to Double Strand Breaks (DSBs) by replication fork collapse and ATM, a member of the phosphatidylinositol 3-kinase (PI3K) family, is a key factor that initiates DNA repair and activates cell cycle checkpoints. Here we demonstrate that the treatment of intracellular tachyzoites with the PI3K inhibitor caffeine or ATM kinase-inhibitor KU-55933 affects parasite replication rate in a dose-dependent manner. KU-55933 affects intracellular tachyzoite growth and induces G1-phase arrest. Addition of KU-55933 to extracellular tachyzoites also leads to a significant reduction of tachyzoite replication upon infection of host cells. ATM kinase phosphorylates H2A.X (γH2AX) to promote DSB damage repair. The level of γH2AX increases in tachyzoites treated with camptothecin (CPT), a drug that generates fork collapse, but this increase was not observed when co-administered with KU-55933. These findings support that KU-55933 is affecting the Toxoplasma ATM-like kinase (TgATM). The combination of KU-55933 and other DNA damaging agents such as methyl methane sulfonate (MMS) and CPT produce a synergic effect, suggesting that TgATM kinase inhibition sensitizes the parasite to damaged DNA. By contrast, hydroxyurea (HU) did not further inhibit tachyzoite replication when combined with KU-55933.
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Affiliation(s)
- Jonathan Munera López
- Laboratorio de Parasitología Molecular, IIB-INTECH, Consejo Nacional de Investigaciones Científicas (CONICET)-Universidad Nacional General San Martin (UNSAM), Chascomús, Argentina
| | - Agustina Ganuza
- Laboratorio de Parasitología Molecular, IIB-INTECH, Consejo Nacional de Investigaciones Científicas (CONICET)-Universidad Nacional General San Martin (UNSAM), Chascomús, Argentina
| | - Silvina S Bogado
- Laboratorio de Parasitología Molecular, IIB-INTECH, Consejo Nacional de Investigaciones Científicas (CONICET)-Universidad Nacional General San Martin (UNSAM), Chascomús, Argentina
| | - Daniela Muñoz
- Laboratorio de Parasitología Molecular, IIB-INTECH, Consejo Nacional de Investigaciones Científicas (CONICET)-Universidad Nacional General San Martin (UNSAM), Chascomús, Argentina
| | - Diego M Ruiz
- Laboratorio de Parasitología Molecular, IIB-INTECH, Consejo Nacional de Investigaciones Científicas (CONICET)-Universidad Nacional General San Martin (UNSAM), Chascomús, Argentina
| | - William J Sullivan
- Pharmacology and Toxicology, Indiana University School of Medicine, Indianapolis, IN, United States.,Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, IN, United States
| | - Laura Vanagas
- Laboratorio de Parasitología Molecular, IIB-INTECH, Consejo Nacional de Investigaciones Científicas (CONICET)-Universidad Nacional General San Martin (UNSAM), Chascomús, Argentina
| | - Sergio O Angel
- Laboratorio de Parasitología Molecular, IIB-INTECH, Consejo Nacional de Investigaciones Científicas (CONICET)-Universidad Nacional General San Martin (UNSAM), Chascomús, Argentina
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11
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White MW, Suvorova ES. Apicomplexa Cell Cycles: Something Old, Borrowed, Lost, and New. Trends Parasitol 2018; 34:759-771. [PMID: 30078701 PMCID: PMC6157590 DOI: 10.1016/j.pt.2018.07.006] [Citation(s) in RCA: 36] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2018] [Revised: 07/09/2018] [Accepted: 07/10/2018] [Indexed: 02/04/2023]
Abstract
Increased parasite burden is linked to the severity of clinical disease caused by Apicomplexa parasites such as Toxoplasma gondii, Plasmodium spp, and Cryptosporidium. Pathogenesis of apicomplexan infections is greatly affected by the growth rate of the parasite asexual stages. This review discusses recent advances in deciphering the mitotic structures and cell cycle regulatory factors required by Apicomplexa parasites to replicate. As the molecular details become clearer, it is evident that the highly unconventional cell cycles of these parasites is a blending of many ancient and borrowed elements, which were then adapted to enable apicomplexan proliferation in a wide variety of different animal hosts.
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Affiliation(s)
- Michael W White
- Department of Global Health, College of Public Health, University of South Florida, Tampa, FL 33612, USA
| | - Elena S Suvorova
- Department of Global Health, College of Public Health, University of South Florida, Tampa, FL 33612, USA.
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12
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Abstract
Toxoplasma gondii is a common veterinary and human pathogen that persists as latent bradyzoite forms within infected hosts. The ability of the parasite to interconvert between tachyzoite and bradyzoite is key for pathogenesis of toxoplasmosis, particularly in immunocompromised individuals. The transition between tachyzoites and bradyzoites is epigenetically regulated and coupled to the cell cycle. Recent epigenomic studies have begun to elucidate the chromatin states associated with developmental switches in T. gondii. Evidence is also emerging that AP2 transcription factors both activate and repress the bradyzoite developmental program. Further studies are needed to understand the mechanisms by which T. gondii transduces environmental signals to coordinate the epigenetic and transcriptional machinery that are responsible for tachyzoite-bradyzoite interconversion.
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Affiliation(s)
- Kami Kim
- Department of Internal Medicine, Division of Infectious Diseases and International Medicine, Morsani College of Medicine, University of South Florida, Tampa, Florida 33612, USA.,Department of Global Health, College of Public Health, University of South Florida, Tampa, Florida 33612, USA;
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13
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Fenoy IM, Bogado SS, Contreras SM, Gottifredi V, Angel SO. The Knowns Unknowns: Exploring the Homologous Recombination Repair Pathway in Toxoplasma gondii. Front Microbiol 2016; 7:627. [PMID: 27199954 PMCID: PMC4853372 DOI: 10.3389/fmicb.2016.00627] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2015] [Accepted: 04/18/2016] [Indexed: 12/17/2022] Open
Abstract
Toxoplasma gondii is an apicomplexan parasite of medical and veterinary importance which causes toxoplasmosis in humans. Great effort is currently being devoted toward the identification of novel drugs capable of targeting such illness. In this context, we believe that the thorough understanding of the life cycle of this model parasite will facilitate the identification of new druggable targets in T. gondii. It is important to exploit the available knowledge of pathways which could modulate the sensitivity of the parasite to DNA damaging agents. The homologous recombination repair (HRR) pathway may be of particular interest in this regard as its inactivation sensitizes other cellular models such as human cancer to targeted therapy. Herein we discuss the information available on T. gondii's HRR pathway from the perspective of its conservation with respect to yeast and humans. Special attention was devoted to BRCT domain-containing and end-resection associated proteins in T. gondii as in other experimental models such proteins have crucial roles in early/late steps or HRR and in the pathway choice for double strand break resolution. We conclude that T. gondii HRR pathway is a source of several lines of investigation that allow to to comprehend the extent of diversification of HRR in T. gondii. Such an effort will serve to determine if HRR could represent a potential targer for the treatment of toxoplasmosis.
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Affiliation(s)
- Ignacio M Fenoy
- Laboratorio de Parasitología Molecular, IIB-INTECH, CONICET-UNSAM Chascomús, Argentina
| | - Silvina S Bogado
- Laboratorio de Parasitología Molecular, IIB-INTECH, CONICET-UNSAM Chascomús, Argentina
| | - Susana M Contreras
- Laboratorio de Parasitología Molecular, IIB-INTECH, CONICET-UNSAM Chascomús, Argentina
| | - Vanesa Gottifredi
- Cell Cycle Genomic Instability Laboratory, Fundación Instituto Leloir, IIBBA-CONICET Chascomús, Argentina
| | - Sergio O Angel
- Laboratorio de Parasitología Molecular, IIB-INTECH, CONICET-UNSAM Chascomús, Argentina
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14
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DNA damage regulation and its role in drug-related phenotypes in the malaria parasites. Sci Rep 2016; 6:23603. [PMID: 27033103 PMCID: PMC4817041 DOI: 10.1038/srep23603] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2015] [Accepted: 03/10/2016] [Indexed: 11/29/2022] Open
Abstract
DNA of malaria parasites, Plasmodium falciparum, is subjected to extraordinary high levels of genotoxic insults during its complex life cycle within both the mosquito and human host. Accordingly, most of the components of DNA repair machinery are conserved in the parasite genome. Here, we investigated the genome-wide responses of P. falciparum to DNA damaging agents and provided transcriptional evidence of the existence of the double strand break and excision repair system. We also showed that acetylation at H3K9, H4K8, and H3K56 play a role in the direct and indirect response to DNA damage induced by an alkylating agent, methyl methanesulphonate (MMS). Artemisinin, the first line antimalarial chemotherapeutics elicits a similar response compared to MMS which suggests its activity as a DNA damaging agent. Moreover, in contrast to the wild-type P. falciparum, two strains (Dd2 and W2) previously shown to exhibit a mutator phenotype, fail to induce their DNA repair upon MMS-induced DNA damage. Genome sequencing of the two mutator strains identified point mutations in 18 DNA repair genes which may contribute to this phenomenon.
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15
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Garcinol Inhibits GCN5-Mediated Lysine Acetyltransferase Activity and Prevents Replication of the Parasite Toxoplasma gondii. Antimicrob Agents Chemother 2016; 60:2164-70. [PMID: 26810649 DOI: 10.1128/aac.03059-15] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2015] [Accepted: 01/16/2016] [Indexed: 12/22/2022] Open
Abstract
Lysine acetylation is a critical posttranslational modification that influences protein activity, stability, and binding properties. The acetylation of histone proteins in particular is a well-characterized feature of gene expression regulation. In the protozoan parasiteToxoplasma gondii, a number of lysine acetyltransferases (KATs) contribute to gene expression and are essential for parasite viability. The natural product garcinol was recently reported to inhibit enzymatic activities of GCN5 and p300 family KATs in other species. Here we show that garcinol inhibits TgGCN5b, the only nuclear GCN5 family KAT known to be required forToxoplasmatachyzoite replication. Treatment of tachyzoites with garcinol led to a reduction of global lysine acetylation, particularly on histone H3 and TgGCN5b itself. We also performed transcriptome sequencing (RNA-seq), which revealed increasing aberrant gene expression coincident with increasing concentrations of garcinol. The majority of the genes that were most significantly affected by garcinol were also associated with TgGCN5b in a previously reported chromatin immunoprecipitation assay with microarray technology (ChIP-chip) analysis. The dysregulated gene expression induced by garcinol significantly inhibitsToxoplasmatachyzoite replication, and the concentrations used exhibit no overt toxicity on human host cells. Garcinol also inhibitsPlasmodium falciparumasexual replication with a 50% inhibitory concentration (IC50) similar to that forToxoplasma Together, these data support that pharmacological inhibition of TgGCN5b leads to a catastrophic failure in gene expression control that prevents parasite replication.
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16
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Martínez-Espinosa R, Argüello-García R, Saavedra E, Ortega-Pierres G. Albendazole induces oxidative stress and DNA damage in the parasitic protozoan Giardia duodenalis. Front Microbiol 2015; 6:800. [PMID: 26300866 PMCID: PMC4526806 DOI: 10.3389/fmicb.2015.00800] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2015] [Accepted: 07/22/2015] [Indexed: 12/15/2022] Open
Abstract
The control of Giardia duodenalis infections is carried out mainly by drugs, among these albendazole (ABZ) is commonly used. Although the cytotoxic effect of ABZ usually involves binding to β-tubulin, it has been suggested that oxidative stress may also play a role in its parasiticidal mechanism. In this work the effect of ABZ in Giardia clones that are susceptible or resistant to different concentrations (1.35, 8, and 250 μM) of this drug was analyzed. Reactive oxygen species (ROS) were induced by ABZ in susceptible clones and this was associated with a decrease in growth that was alleviated by cysteine supplementation. Remarkably, ABZ-resistant clones exhibited partial cross-resistance to H2O2, whereas a Giardia H2O2-resistant strain can grow in the presence of ABZ. Lipid oxidation and protein carbonylation in ABZ-treated parasites did not show significant differences as compared to untreated parasites; however, ABZ induced the formation of 8OHdG adducts and DNA degradation, indicating nucleic acid oxidative damage. This was supported by observations of histone H2AX phosphorylation in ABZ-susceptible trophozoites treated with 250 μM ABZ. Flow cytometry analysis showed that ABZ partially arrested cell cycle in drug-susceptible clones at G2/M phase at the expense of cells in G1 phase. Also, ABZ treatment resulted in phosphatidylserine exposure on the parasite surface, an event related to apoptosis. All together these data suggest that ROS induced by ABZ affect Giardia genetic material through oxidative stress mechanisms and subsequent induction of apoptotic-like events.
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Affiliation(s)
- Rodrigo Martínez-Espinosa
- Departamento de Genética y Biología Molecular, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional México City, Mexico
| | - Raúl Argüello-García
- Departamento de Genética y Biología Molecular, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional México City, Mexico
| | - Emma Saavedra
- Department of Biochemistry, Instituto Nacional de Cardiología Ignacio Chávez México City, Mexico
| | - Guadalupe Ortega-Pierres
- Departamento de Genética y Biología Molecular, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional México City, Mexico
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17
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Simó-Riudalbas L, Pérez-Salvia M, Setien F, Villanueva A, Moutinho C, Martínez-Cardús A, Moran S, Berdasco M, Gomez A, Vidal E, Soler M, Heyn H, Vaquero A, de la Torre C, Barceló-Batllori S, Vidal A, Roz L, Pastorino U, Szakszon K, Borck G, Moura CS, Carneiro F, Zondervan I, Savola S, Iwakawa R, Kohno T, Yokota J, Esteller M. KAT6B Is a Tumor Suppressor Histone H3 Lysine 23 Acetyltransferase Undergoing Genomic Loss in Small Cell Lung Cancer. Cancer Res 2015. [PMID: 26208904 DOI: 10.1158/0008-5472.can-14-3702] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Recent efforts to sequence human cancer genomes have highlighted that point mutations in genes involved in the epigenetic setting occur in tumor cells. Small cell lung cancer (SCLC) is an aggressive tumor with poor prognosis, where little is known about the genetic events related to its development. Herein, we have identified the presence of homozygous deletions of the candidate histone acetyltransferase KAT6B, and the loss of the corresponding transcript, in SCLC cell lines and primary tumors. Furthermore, we show, in vitro and in vivo, that the depletion of KAT6B expression enhances cancer growth, while its restoration induces tumor suppressor-like features. Most importantly, we demonstrate that KAT6B exerts its tumor-inhibitory role through a newly defined type of histone H3 Lys23 acetyltransferase activity.
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Affiliation(s)
- Laia Simó-Riudalbas
- Cancer Epigenetics Group, Cancer Epigenetics and Biology Program (PEBC), Bellvitge Biomedical Research Institute (IDIBELL), Barcelona, Catalonia, Spain
| | - Montserrat Pérez-Salvia
- Cancer Epigenetics Group, Cancer Epigenetics and Biology Program (PEBC), Bellvitge Biomedical Research Institute (IDIBELL), Barcelona, Catalonia, Spain
| | - Fernando Setien
- Cancer Epigenetics Group, Cancer Epigenetics and Biology Program (PEBC), Bellvitge Biomedical Research Institute (IDIBELL), Barcelona, Catalonia, Spain
| | - Alberto Villanueva
- Translational Research Laboratory, Catalan Institute of Oncology (ICO), IDIBELL, Barcelona, Catalonia, Spain
| | - Catia Moutinho
- Cancer Epigenetics Group, Cancer Epigenetics and Biology Program (PEBC), Bellvitge Biomedical Research Institute (IDIBELL), Barcelona, Catalonia, Spain
| | - Anna Martínez-Cardús
- Cancer Epigenetics Group, Cancer Epigenetics and Biology Program (PEBC), Bellvitge Biomedical Research Institute (IDIBELL), Barcelona, Catalonia, Spain
| | - Sebastian Moran
- Cancer Epigenetics Group, Cancer Epigenetics and Biology Program (PEBC), Bellvitge Biomedical Research Institute (IDIBELL), Barcelona, Catalonia, Spain
| | - Maria Berdasco
- Cancer Epigenetics Group, Cancer Epigenetics and Biology Program (PEBC), Bellvitge Biomedical Research Institute (IDIBELL), Barcelona, Catalonia, Spain
| | - Antonio Gomez
- Cancer Epigenetics Group, Cancer Epigenetics and Biology Program (PEBC), Bellvitge Biomedical Research Institute (IDIBELL), Barcelona, Catalonia, Spain
| | - Enrique Vidal
- Cancer Epigenetics Group, Cancer Epigenetics and Biology Program (PEBC), Bellvitge Biomedical Research Institute (IDIBELL), Barcelona, Catalonia, Spain
| | - Marta Soler
- Cancer Epigenetics Group, Cancer Epigenetics and Biology Program (PEBC), Bellvitge Biomedical Research Institute (IDIBELL), Barcelona, Catalonia, Spain
| | - Holger Heyn
- Cancer Epigenetics Group, Cancer Epigenetics and Biology Program (PEBC), Bellvitge Biomedical Research Institute (IDIBELL), Barcelona, Catalonia, Spain
| | | | | | | | - August Vidal
- Department of Pathology, Bellvitge University Hospital, IDIBELL, Barcelona, Catalonia, Spain
| | - Luca Roz
- Tumor Genomics Unit, Department of Experimental Oncology and Molecular Medicine, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy
| | - Ugo Pastorino
- Thoracic Surgery Unit, Department of Surgery, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy
| | - Katalin Szakszon
- Institute of Pediatrics, Clinical Genetics Center, University of Debrecen, Debrecen, Hungary
| | - Guntram Borck
- Institute of Human Genetics, University of Ulm, Ulm, Germany
| | - Conceição S Moura
- Department of Pathology, Centro Hospitalar de São João, Porto, Portugal
| | - Fátima Carneiro
- Institute of Molecular Pathology and Immunology of the University of Porto (IPATIMUP) and Medical Faculty of University of Porto, Porto, Portugal
| | | | | | - Reika Iwakawa
- Division of Genome Biology, National Cancer Center Research Institute, Tokyo, Japan
| | - Takashi Kohno
- Division of Genome Biology, National Cancer Center Research Institute, Tokyo, Japan
| | - Jun Yokota
- Division of Genome Biology, National Cancer Center Research Institute, Tokyo, Japan. Genomics and Epigenomics of Cancer Prediction Program, Institute of Predictive and Personalized Medicine of Cancer (IMPPC), Badalona, Catalonia, Spain
| | - Manel Esteller
- Cancer Epigenetics Group, Cancer Epigenetics and Biology Program (PEBC), Bellvitge Biomedical Research Institute (IDIBELL), Barcelona, Catalonia, Spain. Department of Physiological Sciences II, School of Medicine, University of Barcelona, Barcelona, Catalonia, Spain. Institucio Catalana de Recerca i Estudis Avançats (ICREA), Barcelona, Catalonia, Spain.
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18
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Kumar D, Saha S. HAT3-mediated acetylation of PCNA precedes PCNA monoubiquitination following exposure to UV radiation in Leishmania donovani. Nucleic Acids Res 2015; 43:5423-41. [PMID: 25948582 PMCID: PMC4477661 DOI: 10.1093/nar/gkv431] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2015] [Accepted: 04/22/2015] [Indexed: 12/17/2022] Open
Abstract
Histone modifications impact various processes. In examining histone acetyltranferase HAT3 of Leishmania donovani, we find elimination of HAT3 causes decreased cell viability due to defects in histone deposition, and aberrant cell cycle progression pattern. HAT3 associates with proliferating cell nuclear antigen (PCNA), helping load PCNA onto chromatin in proliferating cells. HAT3-nulls show heightened sensitivity to UV radiation. Following UV exposure, PCNA cycles off/on chromatin only in cells expressing HAT3. Inhibition of the ubiquitin-proteasome pathway prior to UV exposure allows accumulation of chromatin-bound PCNA, and reveals that HAT3-nulls are deficient in PCNA monoubiquitination as well as polyubiquitination. While poor monoubiquitination of PCNA may adversely affect translesion DNA synthesis-based repair processes, polyubiquitination deficiencies may result in continued retention of chromatin-bound PCNA, leading to genomic instability. On suppressing the proteasome pathway we also find that HAT3 mediates PCNA acetylation in response to UV. HAT3-mediated PCNA acetylation may serve as a flag for PCNA ubiquitination, thus aiding DNA repair. While PCNA acetylation has previously been linked to its degradation following UV exposure, this is the first report linking a HAT-mediated PCNA acetylation to PCNA monoubiquitination. These findings add a new dimension to our knowledge of the mechanisms regulating PCNA ubiquitination post-UV exposure in eukaryotes.
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Affiliation(s)
- Devanand Kumar
- Department of Microbiology, University of Delhi South Campus, Benito Juarez Road, New Delhi 110021, India
| | - Swati Saha
- Department of Microbiology, University of Delhi South Campus, Benito Juarez Road, New Delhi 110021, India
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19
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Stilger KL, Sullivan WJ. Elongator protein 3 (Elp3) lysine acetyltransferase is a tail-anchored mitochondrial protein in Toxoplasma gondii. J Biol Chem 2013; 288:25318-25329. [PMID: 23878194 DOI: 10.1074/jbc.m113.491373] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Lysine acetylation has recently emerged as an important, widespread post-translational modification occurring on proteins that reside in multiple cellular compartments, including the mitochondria. However, no lysine acetyltransferase (KAT) has been definitively localized to this organelle to date. Here we describe the identification of an unusual homologue of Elp3 in early-branching protozoa in the phylum Apicomplexa. Elp3 is the catalytic subunit of the well-conserved transcription Elongator complex; however, Apicomplexa lack all other Elongator subunits, suggesting that the Elp3 in these organisms plays a role independent of transcription. Surprisingly, Elp3 in the parasites of this phylum, including Toxoplasma gondii (TgElp3), possesses a unique C-terminal transmembrane domain (TMD) that localizes the protein to the mitochondrion. As TgElp3 is devoid of known mitochondrial targeting signals, we used selective permeabilization studies to reveal that this KAT is oriented with its catalytic components facing the cytosol and its C-terminal TMD inserted into the outer mitochondrial membrane, consistent with a tail-anchored membrane protein. Elp3 trafficking to mitochondria is not exclusive to Toxoplasma as we also present evidence that a form of Elp3 localizes to these organelles in mammalian cells, supporting the idea that Elp3 performs novel functions across eukaryotes that are independent of transcriptional elongation. Importantly, we also present genetic studies that suggest TgElp3 is essential in Toxoplasma and must be positioned at the mitochondrial surface for parasite viability.
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Affiliation(s)
| | - William J Sullivan
- From the Departments of Pharmacology and Toxicology and; Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, Indiana 46202.
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20
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Vanagas L, Jeffers V, Bogado SS, Dalmasso MC, Sullivan WJ, Angel SO. Toxoplasma histone acetylation remodelers as novel drug targets. Expert Rev Anti Infect Ther 2013. [PMID: 23199404 DOI: 10.1586/eri.12.100] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Toxoplasma gondii is a leading cause of neurological birth defects and a serious opportunistic pathogen. The authors and others have found that Toxoplasma uses a unique nucleosome composition supporting a fine gene regulation together with other factors. Post-translational modifications in histones facilitate the establishment of a global chromatin environment and orchestrate DNA-related biological processes. Histone acetylation is one of the most prominent post-translational modifications influencing gene expression. Histone acetyltransferases and histone deacetylases have been intensively studied as potential drug targets. In particular, histone deacetylase inhibitors have activity against apicomplexan parasites, underscoring their potential as a new class of antiparasitic compounds. In this review, we summarize what is known about Toxoplasma histone acetyltransferases and histone deacetylases, and discuss the inhibitors studied to date. Finally, the authors discuss the distinct possibility that the unique nucleosome composition of Toxoplasma, which harbors a nonconserved H2Bv variant histone, might be targeted in novel therapeutics directed against this parasite.
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Affiliation(s)
- Laura Vanagas
- Laboratorio de Parasitología Molecular, IIB-INTECH, CONICET-UNSAM, Av. Intendente Marino Km. 8.2, C.C 164, (B7130IIWA), Chascomús, Prov. Buenos Aires, Argentina.
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21
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Abstract
Epigenetic modifications constitute the next frontier in tumor biology research. Post-translation modification of histones dynamically influences gene expression independent of alterations to the DNA sequence. These mechanisms are often mediated by histone linkers or by proteins associated with the recruitment of DNA-binding proteins, HDAC I and II interacting proteins and transcriptional activators, coactivators or corepressors. Early evidence suggested that histones and their modifiers are involved in sophisticated processes that modulate tumor behavior and cellular phenotype. In this review, we discuss how recent discoveries about chromatin modifications, particularly histone acetylation, are shaping our knowledge of cell biology and our understanding of the molecular circuitry governing tumor progression and consider whether recent insights may extend to novel therapeutic approaches. Furthermore, we discuss the latest oncogenomic findings in Head and Neck Squamous Cell Carcinoma (HNSCC) from studies using Next Generation Sequencing (NGS) technology and highlight the impact of mutations identified in histones and their modifiers.
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Affiliation(s)
- Manoela D Martins
- Department of Oral Pathology, Federal University of Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Rogerio M Castilho
- Laboratory of Epithelial Biology, Department of Periodontics and Oral Medicine, University of Michigan School of Dentistry, Ann Arbor, MI, USA
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22
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Lysine acetylation is widespread on proteins of diverse function and localization in the protozoan parasite Toxoplasma gondii. EUKARYOTIC CELL 2012; 11:735-42. [PMID: 22544907 DOI: 10.1128/ec.00088-12] [Citation(s) in RCA: 91] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
While histone proteins are the founding members of lysine acetylation substrates, it is now clear that hundreds of other proteins can be acetylated in multiple compartments of the cell. Our knowledge of the scope of this modification throughout the kingdom of life is beginning to emerge, as proteome-wide lysine acetylation has been documented in prokaryotes, Arabidopsis thaliana, Drosophila melanogaster, and human cells. Using liquid chromatography-tandem mass spectrometry (LC-MS/MS) to identify parasite peptides enriched by immunopurification with acetyl-lysine antibody, we produced the first proteome-wide analysis of acetylation for a protozoan organism, the opportunistic apicomplexan parasite Toxoplasma gondii. The results show that lysine acetylation is abundant in the actively proliferating tachyzoite form of the parasite, which causes acute toxoplasmosis. Our approach successfully identified known acetylation marks on Toxoplasma histones and α-tubulin and detected over 400 novel acetylation sites on a wide variety of additional proteins, including those with roles in transcription, translation, metabolism, and stress responses. Importantly, an extensive set of parasite-specific proteins, including those found in organelles unique to Apicomplexa, is acetylated in the parasite. Our data provide a wealth of new information that improves our understanding of the evolution of this vital regulatory modification while potentially revealing novel therapeutic avenues. We conclude from this study that lysine acetylation was prevalent in the early stages of eukaryotic cell evolution and occurs on proteins involved in a remarkably diverse array of cellular functions, including those that are specific to parasites.
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23
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Chromatin modifications, epigenetics, and how protozoan parasites regulate their lives. Trends Parasitol 2012; 28:202-13. [PMID: 22480826 DOI: 10.1016/j.pt.2012.02.009] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2012] [Revised: 02/21/2012] [Accepted: 02/29/2012] [Indexed: 12/19/2022]
Abstract
Chromatin structure plays a vital role in epigenetic regulation of protozoan parasite gene expression. Epigenetic gene regulation impacts upon parasite virulence, differentiation and cell-cycle control. Recent work in many laboratories has elucidated the functions of proteins that regulate parasite gene expression by chemical modification of constituent nucleosomes. A major focus of investigation has been the characterization of post-translational modifications (PTMs) of histones and the identification of the enzymes responsible. Despite conserved features and specificity common to all eukaryotes, parasite enzymes involved in chromatin modification have unique functions that regulate unique aspects of parasite biology.
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24
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Novel N-benzoyl-2-hydroxybenzamide disrupts unique parasite secretory pathway. Antimicrob Agents Chemother 2012; 56:2666-82. [PMID: 22354304 DOI: 10.1128/aac.06450-11] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Toxoplasma gondii is a protozoan parasite that can damage the human brain and eyes. There are no curative medicines. Herein, we describe our discovery of N-benzoyl-2-hydroxybenzamides as a class of compounds effective in the low nanomolar range against T. gondii in vitro and in vivo. Our lead compound, QQ-437, displays robust activity against the parasite and could be useful as a new scaffold for development of novel and improved inhibitors of T. gondii. Our genome-wide investigations reveal a specific mechanism of resistance to N-benzoyl-2-hydroxybenzamides mediated by adaptin-3β, a large protein from the secretory protein complex. N-Benzoyl-2-hydroxybenzamide-resistant clones have alterations of their secretory pathway, which traffics proteins to micronemes, rhoptries, dense granules, and acidocalcisomes/plant-like vacuole (PLVs). N-Benzoyl-2-hydroxybenzamide treatment also alters micronemes, rhoptries, the contents of dense granules, and, most markedly, acidocalcisomes/PLVs. Furthermore, QQ-437 is active against chloroquine-resistant Plasmodium falciparum. Our studies reveal a novel class of compounds that disrupts a unique secretory pathway of T. gondii, with the potential to be used as scaffolds in the search for improved compounds to treat the devastating diseases caused by apicomplexan parasites.
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25
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Kumar D, Rajanala K, Minocha N, Saha S. Histone H4 lysine 14 acetylation in Leishmania donovani is mediated by the MYST-family protein HAT4. Microbiology (Reading) 2012; 158:328-337. [DOI: 10.1099/mic.0.050211-0] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Affiliation(s)
- Devanand Kumar
- Department of Microbiology, University of Delhi South Campus, Benito Juarez Road, New Delhi 110021, India
| | - Kalpana Rajanala
- National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi 110067, India
| | - Neha Minocha
- Department of Microbiology, University of Delhi South Campus, Benito Juarez Road, New Delhi 110021, India
| | - Swati Saha
- Department of Microbiology, University of Delhi South Campus, Benito Juarez Road, New Delhi 110021, India
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26
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Naguleswaran A, Elias EV, McClintick J, Edenberg HJ, Sullivan WJ. Toxoplasma gondii lysine acetyltransferase GCN5-A functions in the cellular response to alkaline stress and expression of cyst genes. PLoS Pathog 2010; 6:e1001232. [PMID: 21179246 PMCID: PMC3003489 DOI: 10.1371/journal.ppat.1001232] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2010] [Accepted: 11/16/2010] [Indexed: 12/17/2022] Open
Abstract
Parasitic protozoa such as the apicomplexan Toxoplasma gondii progress through their life cycle in response to stimuli in the environment or host organism. Very little is known about how proliferating tachyzoites reprogram their expressed genome in response to stresses that prompt development into latent bradyzoite cysts. We have previously linked histone acetylation with the expression of stage-specific genes, but the factors involved remain to be determined. We sought to determine if GCN5, which operates as a transcriptional co-activator by virtue of its histone acetyltransferase (HAT) activity, contributed to stress-induced changes in gene expression in Toxoplasma. In contrast to other lower eukaryotes, Toxoplasma has duplicated its GCN5 lysine acetyltransferase (KAT). Disruption of the gene encoding for TgGCN5-A in type I RH strain did not produce a severe phenotype under normal culture conditions, but here we show that the TgGCN5-A null mutant is deficient in responding to alkaline pH, a common stress used to induce bradyzoite differentiation in vitro. We performed a genome-wide analysis of the Toxoplasma transcriptional response to alkaline pH stress, finding that parasites deleted for TgGCN5-A fail to up-regulate 74% of the stress response genes that are induced 2-fold or more in wild-type. Using chromatin immunoprecipitation, we verify an enrichment of TgGCN5-A at the upstream regions of genes activated by alkaline pH exposure. The TgGCN5-A knockout is also incapable of up-regulating key marker genes expressed during development of the latent cyst form, and is impaired in its ability to recover from alkaline stress. Complementation of the TgGCN5-A knockout restores the expression of these stress-induced genes and reverses the stress recovery defect. These results establish TgGCN5-A as a major contributor to the alkaline stress response in RH strain Toxoplasma. Protozoan parasites cause significant disease in humans and livestock, and many of our current therapies have serious side effects or are being rendered useless due to the development of drug resistance. These parasites typically have complex life cycles involving multiple hosts and some, like Toxoplasma gondii, have the ability to remain in the host for life as a latent tissue cyst. Toxoplasma is one of the most successful parasites on Earth because the ability to develop into a tissue cyst greatly facilitates transmission through carnivores. Cyst formation also is responsible for recrudescent infection in immunocompromised patients. The conversion of Toxoplasma from its replicating cell to the cyst is triggered by stress, but we have little understanding of how the parasite stress response functions. In this study, we identify the genes involved in Toxoplasma's response to alkaline stress, which is a known trigger of cyst development. We also establish that a lysine acetyltransferase enzyme called TgGCN5-A is required for type I RH strain Toxoplasma to respond normally to alkaline stress. Parasites lacking TgGCN5-A are no longer capable of activating genes induced during cyst formation triggered by alkaline pH.
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Affiliation(s)
- Arunasalam Naguleswaran
- Department of Pharmacology & Toxicology, Indiana University School of Medicine, Indianapolis, Indiana, United States of America
| | - Eliana V. Elias
- Department of Pharmacology & Toxicology, Indiana University School of Medicine, Indianapolis, Indiana, United States of America
| | - Jeanette McClintick
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana, United States of America
| | - Howard J. Edenberg
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana, United States of America
| | - William J. Sullivan
- Department of Pharmacology & Toxicology, Indiana University School of Medicine, Indianapolis, Indiana, United States of America
- * E-mail:
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The antibiotic monensin causes cell cycle disruption of Toxoplasma gondii mediated through the DNA repair enzyme TgMSH-1. Antimicrob Agents Chemother 2010; 55:745-55. [PMID: 21098240 DOI: 10.1128/aac.01092-10] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Monensin is a polyether ionophore antibiotic that is widely used in the control of coccidia in animals. Despite its significance in veterinary medicine, little is known about its mode of action and potential mechanisms of resistance in coccidian parasites. Here we show that monensin causes accumulation of the coccidian Toxoplasma gondii at an apparent late-S-phase cell cycle checkpoint. In addition, experiments utilizing a monensin-resistant T. gondii mutant show that this effect of monensin is dependent on the function of a mitochondrial homologue of the MutS DNA damage repair enzyme (TgMSH-1). Furthermore, the same TgMSH-1-dependent cell cycle disruption is observed with the antiparasitic ionophore salinomycin and the DNA alkylating agent methyl nitrosourea. Our results suggest a novel mechanism for the mode of action of monensin and salinomycin on coccidial parasites, in which the drug activates an MSH-1-dependent cell cycle checkpoint by an unknown mechanism, ultimately leading to the death of the parasite. This model would indicate that cell cycle disruption is an important mediator of drug susceptibility and resistance to ionophoric antibiotics in coccidian parasites.
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28
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Hutson SL, Mui E, Kinsley K, Witola WH, Behnke MS, El Bissati K, Muench SP, Rohrman B, Liu SR, Wollmann R, Ogata Y, Sarkeshik A, Yates JR, McLeod R. T. gondii RP promoters & knockdown reveal molecular pathways associated with proliferation and cell-cycle arrest. PLoS One 2010; 5:e14057. [PMID: 21124925 PMCID: PMC2989910 DOI: 10.1371/journal.pone.0014057] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2010] [Accepted: 10/25/2010] [Indexed: 01/16/2023] Open
Abstract
Molecular pathways regulating rapid proliferation and persistence are fundamental for pathogens but are not elucidated fully in Toxoplasma gondii. Promoters of T. gondii ribosomal proteins (RPs) were analyzed by EMSAs and ChIP. One RP promoter domain, known to bind an Apetela 2, bound to nuclear extract proteins. Promoter domains appeared to associate with histone acetyl transferases. To study effects of a RP gene's regulation in T. gondii, mutant parasites (Δrps13) were engineered with integration of tetracycline repressor (TetR) response elements in a critical location in the rps13 promoter and transfection of a yellow fluorescent-tetracycline repressor (YFP-TetR). This permitted conditional knockdown of rps13 expression in a tightly regulated manner. Δrps13 parasites were studied in the presence (+ATc) or absence of anhydrotetracycline (-ATc) in culture. -ATc, transcription of the rps13 gene and expression of RPS13 protein were markedly diminished, with concomitant cessation of parasite replication. Study of Δrps13 expressing Myc-tagged RPL22, -ATc, showed RPL22 diminished but at a slower rate. Quantitation of RNA showed diminution of 18S RNA. Depletion of RPS13 caused arrest of parasites in the G1 cell cycle phase, thereby stopping parasite proliferation. Transcriptional differences ±ATc implicate molecules likely to function in regulation of these processes. In vitro, -ATc, Δrps13 persists for months and the proliferation phenotype can be rescued with ATc. In vivo, however, Δrps13 could only be rescued when ATc was given simultaneously and not at any time after 1 week, even when L-NAME and ATc were administered. Immunization with Δrps13 parasites protects mice completely against subsequent challenge with wildtype clonal Type 1 parasites, and robustly protects mice against wildtype clonal Type 2 parasites. Our results demonstrate that G1 arrest by ribosomal protein depletion is associated with persistence of T. gondii in a model system in vitro and immunization with Δrps13 protects mice against subsequent challenge with wildtype parasites.
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Affiliation(s)
- Samuel L. Hutson
- Department of Surgery (Ophthalmology), The University of Chicago, Chicago, Illinois, United States of America
| | - Ernest Mui
- Department of Surgery (Ophthalmology), The University of Chicago, Chicago, Illinois, United States of America
| | - Karen Kinsley
- Department of Surgery (Ophthalmology), The University of Chicago, Chicago, Illinois, United States of America
| | - William H. Witola
- Department of Surgery (Ophthalmology), The University of Chicago, Chicago, Illinois, United States of America
| | - Michael S. Behnke
- Department of Veterinary Molecular Biology, Montana State University, Bozeman, Montana, United States of America
| | - Kamal El Bissati
- Department of Surgery (Ophthalmology), The University of Chicago, Chicago, Illinois, United States of America
| | - Stephen P. Muench
- Institute of Membrane and Systems Biology, University of Leeds, Leeds, United Kingdom
| | - Brittany Rohrman
- Department of Surgery (Ophthalmology), The University of Chicago, Chicago, Illinois, United States of America
| | - Susan R. Liu
- Department of Surgery (Ophthalmology), The University of Chicago, Chicago, Illinois, United States of America
| | - Robert Wollmann
- Department of Pathology, The University of Chicago, Chicago, Illinois, United States of America
| | - Yuko Ogata
- Seattle Biomedical Research Institute, Seattle, Washington, United States of America
| | - Ali Sarkeshik
- Department of Chemical Physiology, Scripps Research Institute, La Jolla, California, United States of America
| | - John R. Yates
- Department of Chemical Physiology, Scripps Research Institute, La Jolla, California, United States of America
| | - Rima McLeod
- Department of Surgery (Ophthalmology), The University of Chicago, Chicago, Illinois, United States of America
- Department of Pediatrics (Infectious Disease), The University of Chicago, Chicago, Illinois, United States of America
- Committees on Immunology, Molecular Medicine, and Genetics, Institute of Genomics and Systems Biology, The College, The University of Chicago, Chicago, Illinois, United States of America
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Miao J, Fan Q, Cui L, Li X, Wang H, Ning G, Reese JC, Cui L. The MYST family histone acetyltransferase regulates gene expression and cell cycle in malaria parasite Plasmodium falciparum. Mol Microbiol 2010; 78:883-902. [PMID: 20807207 DOI: 10.1111/j.1365-2958.2010.07371.x] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Histone lysine acetylation, normally associated with euchromatin and active genes, is regulated by different families of histone acetyltransferases (HATs). A single Plasmodium falciparum MYST (PfMYST) HAT was expressed as a long and a short version in intraerythrocytic stages. Whereas the recombinant PfMYST expressed in prokaryotes and insect cells did not show HAT activity, recombinant PfMYST purified from the parasites exhibited a predilection to acetylate histone H4 in vitro at K5, K8, K12 and K16. Tagging PfMYST with the green fluorescent protein at the C-terminus showed that PfMYST protein was localized in both the nucleus and cytoplasm. Consistent with the importance of H4 acetylation in var gene expression, PfMYST was recruited to the active var promoter. Attempts to disrupt PfMYST were not successful, suggesting that PfMYST is essential for asexual intraerythrocytic growth. However, overexpression of the long, active or a truncated, non-active version of PfMYST by stable integration of the expression cassette in the parasite genome resulted in changes of H4 acetylation and cell cycle progression. Furthermore, parasites with PfMYST overexpression showed changes in sensitivity to DNA-damaging agents. Collectively, this study showed that PfMYST plays important roles in cellular processes such as gene activation, cell cycle control and DNA repair.
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Affiliation(s)
- Jun Miao
- Department of Entomology, The Pennsylvania State University, 501 ASI Bldg., University Park, PA 16802, USA
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Dixon SE, Stilger KL, Elias EV, Naguleswaran A, Sullivan WJ. A decade of epigenetic research in Toxoplasma gondii. Mol Biochem Parasitol 2010; 173:1-9. [PMID: 20470832 DOI: 10.1016/j.molbiopara.2010.05.001] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2010] [Revised: 04/30/2010] [Accepted: 05/04/2010] [Indexed: 11/25/2022]
Abstract
In the past 10 years, the field of parasitology has witnessed an explosion of studies investigating gene regulation. In this review, we will describe recent advances largely stemming from the study of Toxoplasma gondii, a significant opportunistic pathogen and useful model for other apicomplexan protozoa. Surprising findings have emerged, including the discovery of a wealth of epigenetic machinery in these primitive eukaryotes, unusual histone variants, and a battery of plant-like transcription factors. We will elaborate on how these unusual features impact parasite physiology and potential therapeutics as we summarize some of the key discoveries from the last decade. We will close by proposing a few questions to address in the next 10 years.
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Affiliation(s)
- Stacy E Dixon
- Department of Pharmacology & Toxicology, Indiana University School of Medicine, Indianapolis, 46202, United States
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