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1.
Cell Physiol Biochem ; 53(4): 731-745, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31613064

RESUMO

BACKGROUND/AIMS: 3-Deazaneplanocin, DZNep, has been reported to inhibit the EZH2 histone methylase and to induce cell apoptosis in chondrosarcomas (CS). The present study aims to confirm the therapeutic potential of EZH2 inhibitors and investigate the molecular mechanisms of DZNep in chondrosarcomas. METHODS: CS cell lines and primary cultures were used. Apoptosis was investigated using PARP cleavage, caspase 3/7 activity, or Apo2.7 expression. S-adenosylhomocysteine (SAH) and S-adenosylmethionine (SAM) were quantified by UHPLC-MS/MS. Differentially expressed genes in treated-chondrosarcomas and chondrocytes were researched by microarray analysis. RESULTS: DZNep induced apoptosis in chondrosarcomas both in vivo and in vitro. However, this effect was not correlated to EZH2 expression nor activity, and EZH2 knock-down by siRNA did not reduce CS viability. Additionally, the reduction of H3K27me3 induced by GSK126 or tazemetostat (EPZ-6438) did not provoke chondrosarcoma death. However, as expected, DZNep induced SAH accumulation and reduced SAM:SAH ratio. Further, microarray analysis suggests a key role of EGFR in antitumoral effect of DZNep, and pharmacological inhibition of EGFR reduced chondrosarcoma survival. CONCLUSION: EZH2 is not an adequate target for chondrosarcoma treatment. However, DZNep induces apoptosis in chondrosarcomas in vitro and in vivo, by a mechanism likely mediated though EGFR expression. Consequently, it would be worth initiating clinical trials to evaluating efficiency to S-adenosylhomocysteine hydrolase or EGFR inhibitors in patients with chondrosarcomas.


Assuntos
Adenosina/análogos & derivados , Regulação para Baixo/efeitos dos fármacos , Proteína Potenciadora do Homólogo 2 de Zeste/metabolismo , Adenosina/farmacologia , Animais , Apoptose/efeitos dos fármacos , Neoplasias Ósseas/metabolismo , Neoplasias Ósseas/patologia , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Condrossarcoma/metabolismo , Condrossarcoma/patologia , Dano ao DNA/efeitos dos fármacos , Proteína Potenciadora do Homólogo 2 de Zeste/antagonistas & inibidores , Proteína Potenciadora do Homólogo 2 de Zeste/genética , Receptores ErbB/genética , Receptores ErbB/metabolismo , Histonas/metabolismo , Humanos , Masculino , Camundongos , Camundongos Nus , Mapas de Interação de Proteínas/efeitos dos fármacos , Interferência de RNA , RNA Interferente Pequeno/metabolismo , S-Adenosil-Homocisteína/metabolismo
2.
Nat Cell Biol ; 21(10): 1248-1260, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31576060

RESUMO

While nuclear lamina abnormalities are hallmarks of human diseases, their interplay with epigenetic regulators and precise epigenetic landscape remain poorly understood. Here, we show that loss of the lysine acetyltransferase MOF or its associated NSL-complex members KANSL2 or KANSL3 leads to a stochastic accumulation of nuclear abnormalities with genomic instability patterns including chromothripsis. SILAC-based MOF and KANSL2 acetylomes identified lamin A/C as an acetylation target of MOF. HDAC inhibition or acetylation-mimicking lamin A derivatives rescue nuclear abnormalities observed in MOF-deficient cells. Mechanistically, loss of lamin A/C acetylation resulted in its increased solubility, defective phosphorylation dynamics and impaired nuclear mechanostability. We found that nuclear abnormalities include EZH2-dependent histone H3 Lys 27 trimethylation and loss of nascent transcription. We term this altered epigenetic landscape "heterochromatin enrichment in nuclear abnormalities" (HENA). Collectively, the NSL-complex-dependent lamin A/C acetylation provides a mechanism that maintains nuclear architecture and genome integrity.


Assuntos
Núcleo Celular/ultraestrutura , Histona Acetiltransferases/metabolismo , Lamina Tipo A/metabolismo , Proteínas Nucleares/metabolismo , Acetilação , Animais , Núcleo Celular/metabolismo , Células Cultivadas , Epigênese Genética , Fibroblastos , Heterocromatina , Histona Acetiltransferases/genética , Histonas/genética , Histonas/metabolismo , Lamina Tipo A/química , Lamina Tipo A/genética , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Proteínas Nucleares/genética
4.
Enzymes ; 45: 27-57, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31627880

RESUMO

Repair of damaged DNA plays a crucial role in maintaining genomic integrity and normal cell function. The base excision repair (BER) pathway is primarily responsible for removing modified nucleobases that would otherwise cause deleterious and mutagenic consequences and lead to disease. The BER process is initiated by a DNA glycosylase, which recognizes and excises the target nucleobase lesion, and is completed via downstream enzymes acting in a well-coordinated manner. A majority of our current understanding about how BER enzymes function comes from in vitro studies using free duplex DNA as a simplified model. In eukaryotes, however, BER is challenged by the packaging of genomic DNA into chromatin. The fundamental structural repeating unit of chromatin is the nucleosome, which presents a more complex substrate context than free duplex DNA for repair. In this chapter, we discuss how BER enzymes, particularly glycosylases, engage in the context of packaged DNA with insights obtained from both in vivo and in vitro studies. Furthermore, we review factors and mechanisms that can modify chromatin architecture and/or influence DNA accessibility to BER machinery, such as the geometric location of the damage site, nucleosomal DNA unwrapping, histone post-translational modifications, histone variant incorporation, and chromatin remodeling.


Assuntos
Cromatina/química , Cromatina/genética , Dano ao DNA , Reparo do DNA , DNA/química , DNA/metabolismo , Montagem e Desmontagem da Cromatina , DNA/genética , Histonas/química , Histonas/metabolismo , Nucleossomos/química , Nucleossomos/genética
5.
Nature ; 574(7779): 575-580, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31645732

RESUMO

The Warburg effect, which originally described increased production of lactate in cancer, is associated with diverse cellular processes such as angiogenesis, hypoxia, polarization of macrophages and activation of T cells. This phenomenon is intimately linked to several diseases including neoplasia, sepsis and autoimmune diseases1,2. Lactate, which is converted from pyruvate in tumour cells, is widely known as an energy source and metabolic by-product. However, its non-metabolic functions in physiology and disease remain unknown. Here we show that lactate-derived lactylation of histone lysine residues serves as an epigenetic modification that directly stimulates gene transcription from chromatin. We identify 28 lactylation sites on core histones in human and mouse cells. Hypoxia and bacterial challenges induce the production of lactate by glycolysis, and this acts as a precursor that stimulates histone lactylation. Using M1 macrophages that have been exposed to bacteria as a model system, we show that histone lactylation has different temporal dynamics from acetylation. In the late phase of M1 macrophage polarization, increased histone lactylation induces homeostatic genes that are involved in wound healing, including Arg1. Collectively, our results suggest that an endogenous 'lactate clock' in bacterially challenged M1 macrophages turns on gene expression to promote homeostasis. Histone lactylation thus represents an opportunity to improve our understanding of the functions of lactate and its role in diverse pathophysiological conditions, including infection and cancer.


Assuntos
Epigênese Genética , Glicólise/genética , Histonas/química , Histonas/metabolismo , Ácido Láctico/metabolismo , Acetilação , Sequência de Aminoácidos , Animais , Linhagem Celular Tumoral , Cromatina/química , Cromatina/genética , Cromatina/metabolismo , Homeostase , Humanos , Hipóxia/metabolismo , Lisina/química , Lisina/metabolismo , Macrófagos/metabolismo , Macrófagos/microbiologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Reprodutibilidade dos Testes , Transcrição Genética
6.
Nat Cell Biol ; 21(9): 1164-1172, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31481796

RESUMO

Single-cell measurement of chromatin states, including histone modifications and non-histone protein binding, remains challenging. Here, we present a low-cost, efficient, simultaneous indexing and tagmentation-based ChIP-seq (itChIP-seq) method, compatible with both low cellular input and single cells for profiling chromatin states. itChIP combines chromatin opening, simultaneous cellular indexing and chromatin tagmentation within a single tube, enabling the processing of samples from tens of single cells to, more commonly, thousands of single cells per assay. We demonstrate that single-cell itChIP-seq (sc-itChIP-seq) yields ~9,000 unique reads per cell. Using sc-itChIP-seq to profile H3K27ac, we sufficiently capture the earliest epigenetic priming event during the cell fate transition from naive to primed pluripotency, and reveal the basis for cell-type specific enhancer usage during the differentiation of bipotent cardiac progenitor cells into endothelial cells and cardiomyocytes. Our results demonstrate that itChIP is a widely applicable technology for single-cell chromatin profiling of epigenetically heterogeneous cell populations in many biological processes.


Assuntos
Cromatina/metabolismo , Células Endoteliais/metabolismo , Processamento de Proteína Pós-Traducional/genética , Análise de Sequência de DNA , Animais , Sítios de Ligação , Imunoprecipitação da Cromatina/métodos , Epigenômica/métodos , Histonas/metabolismo , Camundongos Transgênicos , Análise de Sequência de DNA/métodos
7.
Genes Dev ; 33(19-20): 1416-1427, 2019 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-31488576

RESUMO

Polycomb-repressive complex 2 (PRC2) is a histone methyltransferase that is critical for regulating transcriptional repression in mammals. Its catalytic subunit, EZH2, is responsible for the trimethylation of H3K27 and also undergoes automethylation. Using mass spectrometry analysis of recombinant human PRC2, we identified three methylated lysine residues (K510, K514, and K515) on a disordered but highly conserved loop of EZH2. Methylation of these lysines increases PRC2 histone methyltransferase activity, whereas their mutation decreases activity in vitro. De novo histone methylation in an EZH2 knockout cell line is greatly impeded by mutation of the automethylation lysines. EZH2 automethylation occurs intramolecularly (in cis) by methylation of a pseudosubstrate sequence on a flexible loop. This posttranslational modification and cis regulation of PRC2 are analogous to the activation of many protein kinases by autophosphorylation. We propose that EZH2 automethylation allows PRC2 to modulate its histone methyltransferase activity by sensing histone H3 tails, SAM concentration, and perhaps other effectors.


Assuntos
Histonas/metabolismo , Complexo Repressor Polycomb 2/metabolismo , Proteína Potenciadora do Homólogo 2 de Zeste/genética , Proteína Potenciadora do Homólogo 2 de Zeste/metabolismo , Ativação Enzimática/fisiologia , Regulação da Expressão Gênica , Humanos , Lisina/metabolismo , Metilação , Processamento de Proteína Pós-Traducional , Proteínas Recombinantes/metabolismo
8.
Genes Dev ; 33(19-20): 1428-1440, 2019 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-31488577

RESUMO

The histone methyltransferase activity of PRC2 is central to the formation of H3K27me3-decorated facultative heterochromatin and gene silencing. In addition, PRC2 has been shown to automethylate its core subunits, EZH1/EZH2 and SUZ12. Here, we identify the lysine residues at which EZH1/EZH2 are automethylated with EZH2-K510 and EZH2-K514 being the major such sites in vivo. Automethylated EZH2/PRC2 exhibits a higher level of histone methyltransferase activity and is required for attaining proper cellular levels of H3K27me3. While occurring independently of PRC2 recruitment to chromatin, automethylation promotes PRC2 accessibility to the histone H3 tail. Intriguingly, EZH2 automethylation is significantly reduced in diffuse intrinsic pontine glioma (DIPG) cells that carry a lysine-to-methionine substitution in histone H3 (H3K27M), but not in cells that carry either EZH2 or EED mutants that abrogate PRC2 allosteric activation, indicating that H3K27M impairs the intrinsic activity of PRC2. Our study demonstrates a PRC2 self-regulatory mechanism through its EZH1/2-mediated automethylation activity.


Assuntos
Glioma/enzimologia , Glioma/genética , Histonas/metabolismo , Criança , Ativação Enzimática , Inativação Gênica , Histonas/genética , Humanos , Lisina/metabolismo , Metilação , Complexo Repressor Polycomb 2/metabolismo , Subunidades Proteicas/genética , Subunidades Proteicas/metabolismo
9.
Nat Chem Biol ; 15(10): 992-1000, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31527837

RESUMO

Post-translational modifications of histone variant H2A.Z accompany gene transactivation, but its modifying enzymes still remain elusive. Here, we reveal a hitherto unknown function of human KAT2A (GCN5) as a histone acetyltransferase (HAT) of H2A.Z at the promoters of a set of transactivated genes. Expression of these genes also depends on the DNA repair complex XPC-RAD23-CEN2. We established that XPC-RAD23-CEN2 interacts both with H2A.Z and KAT2A to drive the recruitment of the HAT at promoters and license H2A.Z acetylation. KAT2A selectively acetylates H2A.Z.1 versus H2A.Z.2 in vitro on several well-defined lysines and we unveiled that alanine-14 in H2A.Z.2 is responsible for inhibiting the activity of KAT2A. Notably, the use of a nonacetylable H2A.Z.1 mutant shows that H2A.Z.1ac recruits the epigenetic reader BRD2 to promote RNA polymerase II recruitment. Our studies identify KAT2A as an H2A.Z.1 HAT in mammals and implicate XPC-RAD23-CEN2 as a transcriptional co-activator licensing the reshaping of the promoter epigenetic landscape.


Assuntos
Reparo do DNA/fisiologia , Histona Acetiltransferases/metabolismo , Histonas/metabolismo , Acetilação , Proteínas de Ligação ao Cálcio/genética , Proteínas de Ligação ao Cálcio/metabolismo , Proteínas de Ciclo Celular/genética , Proteínas de Ciclo Celular/metabolismo , Linhagem Celular , Enzimas Reparadoras do DNA/genética , Enzimas Reparadoras do DNA/metabolismo , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/metabolismo , Fibroblastos , Regulação da Expressão Gênica , Humanos , Lisina Acetiltransferase 5
10.
Toxicol Lett ; 316: 147-153, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31520700

RESUMO

Asthma is a common chronic inflammatory disease which severely reduces the quality of life in patients. Studies have demonstrated that both PM2.5 and cold stress contribute to the development of asthma. However, the combined effects of these two risking factors are unknown. In this study, we investigated the combined effects of PM2.5 exposure and cold stress (PMCS) on asthma, as well as the underlying mechanisms by using a murine model. After different exposures, the immune-pathological changes and redox states in groups were evaluated. Besides, the balance of TH1/TH2 cells and the acetylation levels of H3K9 and H3K14 in IL-4 gene promotor were detected. Our results showed that, compared with other exposures, PMCS led to an increased inflammation and redox levels in mice. It also significantly increased the percentage of TH2 T cells, which was correlated with hyperacetylation of H3K9 and H3K14 in IL-4 gene promoter in CD4+T cells. Furthermore, a significantly increased P300 and decreased HDAC1 were detected in CD4 + T cells in PMCS group. In conclusion, our findings demonstrated that PMCS exacerbated asthma in mice by increasing H3K9 and H3K14 acetylation in IL-4 gene promoter in CD4 + T cells, and P300 and HDAC1 might contribute to their combined effects.


Assuntos
Asma/induzido quimicamente , Temperatura Baixa/efeitos adversos , Histonas/metabolismo , Interleucina-4/metabolismo , Pulmão/efeitos dos fármacos , Material Particulado/toxicidade , Regiões Promotoras Genéticas , Linfócitos T Auxiliares-Indutores/efeitos dos fármacos , Acetilação , Animais , Asma/genética , Asma/imunologia , Asma/metabolismo , Modelos Animais de Doenças , Proteína p300 Associada a E1A/metabolismo , Histona Desacetilase 1/metabolismo , Interleucina-4/genética , Interleucina-4/imunologia , Pulmão/imunologia , Pulmão/metabolismo , Masculino , Camundongos Endogâmicos BALB C , Ovalbumina , Tamanho da Partícula , Processamento de Proteína Pós-Traducional , Linfócitos T Auxiliares-Indutores/imunologia , Linfócitos T Auxiliares-Indutores/metabolismo
11.
Chem Biol Interact ; 313: 108834, 2019 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-31545955

RESUMO

The anthracycline doxorubicin (DOX) is widely used in cancer therapy with the limitation of cardiotoxicity leading to the development of congestive heart failure. DOX-induced oxidative stress and changes of the phosphoproteome as well as epigenome were described but the exact mechanisms of the adverse long-term effects are still elusive. Here, we tested the impact of DOX treatment on cell death, oxidative stress parameters and expression profiles of proteins involved in epigenetic pathways in a cardiomyocyte cell culture model. Markers of oxidative stress, apoptosis and expression of proteins involved in epigenetic processes were assessed by immunoblotting in cultured rat myoblasts (H9c2) upon treatment with DOX (1 or 5 µM for 24 or 48 h) in adherent viable and detached apoptotic cells. The apoptosis markers cleaved caspase-3 and fractin as well as oxidative stress markers 3-nitrotyrosine and malondialdehyde were dose-dependently increased by DOX treatment. Histone deacetylases (SIRT1 and HDAC2), histone lysine demethylases (KDM3A and LSD1) and histone lysine methyltransferases (SET7 and SMYD1) were significantly regulated by DOX treatment with generation of cleaved protein fragments and posttranslational modifications. Overall, we found significant decrease in histone 3 acetylation in DOX-treated cells. DOX treatment of cultured cardiomyocyte precursor cells causes severe cell death by apoptosis associated with cellular oxidative stress. In addition, significant regulation of proteins involved in epigenetic processes and changes in global histone 3 acetylation were observed. However, the significance and clinical impact of these changes remain elusive.


Assuntos
Doxorrubicina/efeitos adversos , Epigênese Genética/efeitos dos fármacos , Miócitos Cardíacos/efeitos dos fármacos , Animais , Antibióticos Antineoplásicos/efeitos adversos , Apoptose/efeitos dos fármacos , Apoptose/genética , Biomarcadores/metabolismo , Cardiotoxicidade/metabolismo , Células Cultivadas , Relação Dose-Resposta a Droga , Histona Desacetilases/metabolismo , Histona Desmetilases/metabolismo , Histonas/metabolismo , Peróxido de Hidrogênio/farmacologia , Miócitos Cardíacos/patologia , Miócitos Cardíacos/fisiologia , Estresse Oxidativo/efeitos dos fármacos , Estresse Oxidativo/fisiologia , Ratos
13.
J Chem Theory Comput ; 15(10): 5659-5673, 2019 Oct 08.
Artigo em Inglês | MEDLINE | ID: mdl-31476125

RESUMO

Human heterochromatin protein 1 (HP1) is a key factor in heterochromatin formation and maintenance. Its chromo-shadow domain (CSD) homodimerizes, and the HP1 dimer acts as a hub, transiently interacting with diverse binding partner (BP) proteins. We analyze atomistic details of interactions of the HP1γ(CSD) dimer with one of its targets, the histone H3 N-terminal tail, using molecular dynamics (MD) simulations. The goal is to complement the available X-ray crystallography data and unravel potential dynamic effects in the molecular recognition. Our results suggest that HP1(CSD)-BP recognition involves structural dynamics of both partners, including structural communication between adjacent binding pockets that may fine-tune the sequence recognition. For example, HP1 Trp174 sidechain substates may help in distinguishing residues bound in the conserved HP1(CSD) ±2 hydrophobic pockets. Further, there is intricate competition between the binding of negatively charged HP1 C-terminal extension and solvent anions near the ±2 hydrophobic pockets, which is also influenced by the BP sequence. Phosphorylated H3 Y41 can interact with the same site. We also analyze the ability of several pair-additive force fields to describe the protein-protein interface. ff14SB and ff99SB-ILDN* provide the closest correspondence with the crystallographic model. The ff15ipq local dynamics are somewhat less consistent with details of the experimental structure, while larger perturbations of the interface commonly occur in CHARMM36m simulations. The balance of some interactions, mainly around the anion binding site, also depends on the ion parameters. Some differences between the simulated and experimental structures are attributable to crystal packing.


Assuntos
Proteínas Cromossômicas não Histona/química , Histonas/química , Cristalografia por Raios X , Dimerização , Histonas/metabolismo , Humanos , Simulação de Dinâmica Molecular , Conformação Proteica
14.
Nat Immunol ; 20(9): 1186-1195, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31384058

RESUMO

Macrophages are activated during microbial infection to coordinate inflammatory responses and host defense. Here we find that in macrophages activated by bacterial lipopolysaccharide (LPS), mitochondrial glycerol 3-phosphate dehydrogenase (GPD2) regulates glucose oxidation to drive inflammatory responses. GPD2, a component of the glycerol phosphate shuttle, boosts glucose oxidation to fuel the production of acetyl coenzyme A, acetylation of histones and induction of genes encoding inflammatory mediators. While acute exposure to LPS drives macrophage activation, prolonged exposure to LPS triggers tolerance to LPS, where macrophages induce immunosuppression to limit the detrimental effects of sustained inflammation. The shift in the inflammatory response is modulated by GPD2, which coordinates a shutdown of oxidative metabolism; this limits the availability of acetyl coenzyme A for histone acetylation at genes encoding inflammatory mediators and thus contributes to the suppression of inflammatory responses. Therefore, GPD2 and the glycerol phosphate shuttle integrate the extent of microbial stimulation with glucose oxidation to balance the beneficial and detrimental effects of the inflammatory response.


Assuntos
Glucose/metabolismo , Glicerolfosfato Desidrogenase/metabolismo , Ativação de Macrófagos/imunologia , Macrófagos/imunologia , Macrófagos/metabolismo , Acetilcoenzima A/biossíntese , Acetilação , Animais , Feminino , Histonas/metabolismo , Inflamação/patologia , Lipopolissacarídeos , Macrófagos/citologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Oxirredução
15.
Nat Commun ; 10(1): 3435, 2019 08 06.
Artigo em Inglês | MEDLINE | ID: mdl-31387991

RESUMO

Histones, the principal protein components of chromatin, contain long disordered sequences, which are extensively post-translationally modified. Although histone chaperones are known to control both the activity and specificity of histone-modifying enzymes, the mechanisms promoting modification of highly disordered substrates, such as lysine-acetylation within the N-terminal tail of histone H3, are not understood. Here, to understand how histone chaperones Asf1 and Vps75 together promote H3 K9-acetylation, we establish the solution structural model of the acetyltransferase Rtt109 in complex with Asf1 and Vps75 and the histone dimer H3:H4. We show that Vps75 promotes K9-acetylation by engaging the H3 N-terminal tail in fuzzy electrostatic interactions with its disordered C-terminal domain, thereby confining the H3 tail to a wide central cavity faced by the Rtt109 active site. These fuzzy interactions between disordered domains achieve localization of lysine residues in the H3 tail to the catalytic site with minimal loss of entropy, and may represent a common mechanism of enzymatic reactions involving highly disordered substrates.


Assuntos
Histona Acetiltransferases/metabolismo , Chaperonas de Histonas/metabolismo , Histonas/metabolismo , Proteínas Intrinsicamente Desordenadas/metabolismo , Acetilação , Domínio Catalítico , Proteínas de Ciclo Celular/isolamento & purificação , Proteínas de Ciclo Celular/metabolismo , Histona Acetiltransferases/isolamento & purificação , Chaperonas de Histonas/isolamento & purificação , Histonas/isolamento & purificação , Lisina/metabolismo , Chaperonas Moleculares/isolamento & purificação , Chaperonas Moleculares/metabolismo , Simulação de Dinâmica Molecular , Ressonância Magnética Nuclear Biomolecular , Processamento de Proteína Pós-Traducional , Proteínas Recombinantes/isolamento & purificação , Proteínas Recombinantes/metabolismo , Proteínas de Saccharomyces cerevisiae/isolamento & purificação , Proteínas de Saccharomyces cerevisiae/metabolismo , Especificidade por Substrato , Proteínas de Xenopus/isolamento & purificação , Proteínas de Xenopus/metabolismo
16.
Genome Biol ; 20(1): 157, 2019 08 07.
Artigo em Inglês | MEDLINE | ID: mdl-31391082

RESUMO

BACKGROUND: Chromatin provides a tunable platform for gene expression control. Besides the well-studied core nucleosome, H1 linker histones are abundant chromatin components with intrinsic potential to influence chromatin function. Well studied in animals, little is known about the evolution of H1 function in other eukaryotic lineages for instance plants. Notably, in the model plant Arabidopsis, while H1 is known to influence heterochromatin and DNA methylation, its contribution to transcription, molecular, and cytological chromatin organization remains elusive. RESULTS: We provide a multi-scale functional study of Arabidopsis linker histones. We show that H1-deficient plants are viable yet show phenotypes in seed dormancy, flowering time, lateral root, and stomata formation-complemented by either or both of the major variants. H1 depletion also impairs pluripotent callus formation. Fine-scale chromatin analyses combined with transcriptome and nucleosome profiling reveal distinct roles of H1 on hetero- and euchromatin: H1 is necessary to form heterochromatic domains yet dispensable for silencing of most transposable elements; H1 depletion affects nucleosome density distribution and mobility in euchromatin, spatial arrangement of nanodomains, histone acetylation, and methylation. These drastic changes affect moderately the transcription but reveal a subset of H1-sensitive genes. CONCLUSIONS: H1 variants have a profound impact on the molecular and spatial (nuclear) chromatin organization in Arabidopsis with distinct roles in euchromatin and heterochromatin and a dual causality on gene expression. Phenotypical analyses further suggest the novel possibility that H1-mediated chromatin organization may contribute to the epigenetic control of developmental and cellular transitions.


Assuntos
Arabidopsis/genética , Cromatina/química , Histonas/fisiologia , Arabidopsis/crescimento & desenvolvimento , Arabidopsis/metabolismo , Epigênese Genética , Eucromatina/química , Regulação da Expressão Gênica de Plantas , Heterocromatina/química , Histonas/genética , Histonas/metabolismo , Mutação , Nucleossomos
17.
Gene ; 718: 144049, 2019 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-31430520

RESUMO

The role of epigenetics in development has garnered attention in recent years due to their ability to modulate the embryonic developmental gene expression in response to the environmental cues. The epigenetic mechanisms - DNA methylation, histone modification, and non-coding RNAs have a unique impact on vertebrate development. Zebrafish, a model vertebrate organism is being used widely in developmental studies due to their high fecundability and rapid organogenesis. With increased studies on various aspects of epigenetics in development, this review gives a glimpse of the major epigenetic modifications and their role in zebrafish development. In this review, the basic mechanism behind each modification followed by their status in zebrafish has been reviewed. Further, recent advancements in the epigenetic aspect of zebrafish development have been discussed.


Assuntos
Metilação de DNA/fisiologia , Embrião não Mamífero/embriologia , Desenvolvimento Embrionário/fisiologia , Epigênese Genética/fisiologia , Regulação da Expressão Gênica no Desenvolvimento/fisiologia , Peixe-Zebra/embriologia , Animais , Histonas/genética , Histonas/metabolismo , Processamento de Proteína Pós-Traducional/fisiologia , Peixe-Zebra/genética
18.
Environ Pollut ; 254(Pt A): 113021, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31415976

RESUMO

Cadmium (Cd) is a ubiquitous toxic heavy metal derived mainly from industrial processes. In industrialized societies, individuals are exposed to a plethora of sources of Cd pollution. Cd can trigger serious diseases such as rheumatoid arthritis (RA) and chronic obstructive pulmonary disease (COPD) by the over-activating immune system. As an effector mechanism in innate immunity, neutrophil extracellular traps (NETs) not only play an important role in defending against infection but also lead to tissue damage. However, the role of NETs in Cd-induced lung damage process has not been previously studied. In this study, we aimed to investigate the potential effects of Cd-induced NETs on lung injury in vivo and further to clarify the molecular mechanisms of Cd-induced NETs formation. In vivo, Cd treatment destroyed the structural integrity of lung tissue and significantly increased the levels of NETs in the bronchoalveolar lavage fluid (BALF). The known NETs inhibitor DNase I ameliorated pathologic changes and significantly decreased levels of NETs in BALF, which suggesting the curial role of NETs in Cd-induced lung injury. Further investigation showed that Cd could significantly trigger NETs formation, which is composed of DNA backbone decorated with histones (H3) and neutrophils elastase (NE). The inhibitors of NADPH oxidase, ERK1/2 and p38 MAPK-signaling pathways significantly reduced the formation of NETs, and western blotting analysis also showed that Cd significantly increased the phosphorylation of p38 and ERK1/2 signaling pathways. Above results confirmed that NADPH oxidase, ERK1/2 and p38 MAPK-signaling pathways were related to Cd-induced NETs formation. In conclusion, NETs was involved in Cd-induced lung injury, and the mechanisms of Cd-induced NETs formation was via activating NADPH oxidase, ERK1/2 and p38 MAPK-signaling pathways, which might provide a new perspective in Cd-induced lung injury.


Assuntos
Cloreto de Cádmio/toxicidade , Armadilhas Extracelulares/fisiologia , Testes de Toxicidade , Animais , Líquido da Lavagem Broncoalveolar , Cádmio/metabolismo , Histonas/metabolismo , Imunidade Inata , Pulmão/metabolismo , Lesão Pulmonar , Sistema de Sinalização das MAP Quinases , Camundongos , NADPH Oxidases , Neutrófilos/efeitos dos fármacos , Oxirredução , Fosforilação , Transdução de Sinais
19.
Life Sci ; 234: 116788, 2019 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-31445935

RESUMO

Livin is an important member of the human inhibitor of apoptosis proteins (IAPs) family. IAPs are proteins with antiapoptotic abilities, and their functions are different from the Bcl-2 (B-cell lymphoma-2) family proteins. However, the precise role of Livin in colon cancer progression remains unclear. The purpose of this study is to assess the effect of overexpression Livin in colon cancer cells and to examine its molecular mechanism. We demonstrated that Livin induced a colon cancer phenotype, including proliferation and migration, by regulating H2A.XY39ph (histone family 2A variant (H2AX) phosphorylated on the 39th serine site). We elucidated that Livin degraded Jumonji-C domain-containing 6 protein (JMJD6), which was mediated by the proteasome murine double minute 2 (MDM2), thereby regulating H2A.XY39ph. Above all, the overexpression of JMJD6 recovered H2A.XY39ph in colon cancer cells with a high level of Livin, thus inhibiting colon cancer malignancy progression. These results reveal a previously unrecognized role for Livin in regulating the tumor-initiating capacity in colon cancer and provide a novel treatment strategy in cancer via the interruption of H2A.XY39ph function and the interaction between H2A.XY39ph and JMJD6.


Assuntos
Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Neoplasias do Colo/patologia , Histonas/metabolismo , Proteínas Inibidoras de Apoptose/metabolismo , Histona Desmetilases com o Domínio Jumonji/metabolismo , Proteínas de Neoplasias/metabolismo , Mapas de Interação de Proteínas , Proteínas Adaptadoras de Transdução de Sinal/genética , Carcinogênese/genética , Carcinogênese/metabolismo , Carcinogênese/patologia , Linhagem Celular Tumoral , Neoplasias do Colo/genética , Neoplasias do Colo/metabolismo , Progressão da Doença , Regulação Neoplásica da Expressão Gênica , Histonas/genética , Humanos , Proteínas Inibidoras de Apoptose/genética , Histona Desmetilases com o Domínio Jumonji/genética , Proteínas de Neoplasias/genética , Proteólise
20.
Results Probl Cell Differ ; 67: 17-25, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31435790

RESUMO

Acetylation is among the most prevalent posttranslational modifications in cells and regulates a number of physiological processes such as gene transcription, cell metabolism, and cell signaling. Although initially discovered on nuclear histones, many non-nuclear proteins have subsequently been found to be acetylated as well. The centrosome is the major microtubule-organizing center in most metazoans. Recent proteomic data indicate that a number of proteins in this subcellular compartment are acetylated. This review gives an overview of our current knowledge on protein acetylation at the centrosome and its functional relevance in organelle biology.


Assuntos
Centrossomo/metabolismo , Processamento de Proteína Pós-Traducional , Proteínas/metabolismo , Acetilação , Animais , Histonas/metabolismo , Humanos , Proteômica
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