scholarly journals Lysine methyltransferase SETD6 modifies histones and non-histone proteins

2016 ◽  
Author(s):  
Olivier Binda
Keyword(s):  
Genetic Information ◽  
Histone Variant ◽  
Histone Proteins ◽  
Lysine Methyltransferase ◽  
Lysine Methyltransferases

ABSTRACTAlthough central to regulating the access to genetic information, most lysine methyltransferases remain poorly characterised relative to other family of enzymes. Herein, we report new substrates for the lysine methyltransferase SETD6. Based on the SETD6- catalysed site on the histone variant H2AZ, we identified similar sequences in the canonical histones H2A, H3, and H4 that are modified by SETD6 in vitro, and putative non-histone substrates. We herein expend the repertoire of substrates for methylation by SETD6.

scholarly journals STEM-29. THE HISTONE VARIANT macroH2A2 ORCHESTRATES AN ACTIONABLE CHROMATIN PROGRAM OF STEMNESS IN GLIOBLASTOMA

2020 ◽  
Vol 22 (Supplement_2) ◽  
pp. ii202-ii202
Author(s):  
Ana Nikolic ◽  
Anna Bobyn ◽  
Katrina Ellestad ◽  
Xueqing Lun ◽  
Michael Johnston ◽  
...  
Keyword(s):  
Chromatin Accessibility ◽  
Histone Variant ◽  
Clinical Settings ◽  
Glioblastoma Cells ◽  
Self Renewal ◽  
Viral Mimicry ◽  
Experimental Findings ◽  
Preclinical Work

Abstract Glioblastoma cells with the crucial stemness property of self-renewal constitute therapy-resistant reservoirs that seed tumor relapse. Effective targeting of these cells in clinical settings has been hampered by their relative quiescence, which invalidates the cell replication bias of most current treatments. Furthermore, although their dependence on specific chromatin and transcriptional states for the maintenance of stemness programs has been proposed as a vulnerability, these nuclear programs have been challenging to target pharmaceutically. Therefore the identification of targetable chromatin paradigms regulating self-renewal would represent a significant advancement for this incurable malignancy. Here we report a new role for the histone variant macroH2A2 in modulating a targetable epigenetic network of stemness in glioblastoma. By integrating transcriptomic, bulk and single-cell epigenomic datasets we generated from patient-derived models and surgical specimens, we show that macroH2A2 represses a transcriptional network of stemness through direct regulation of chromatin accessibility at enhancer elements. Functional assays in vitro and in vivo further showcase that macroH2A2 antagonizes self-renewal and stemness in glioblastoma preclinical models. In agreement with our experimental findings, high expression of macroH2A2 is a positive prognostic factor in clinical glioblastoma cohorts. Reasoning that increasing macroH2A2 levels could be an effective strategy to repress stemness programs and ameliorate patient outcome, we embarked on a screen to identify compounds that could elevate macroH2A2 levels. We report that an inhibitor of the chromatin remodeler Menin increases macroH2A2 levels, which in turn repress self-renewal. Additionally, we provide evidence that Menin inhibition induces viral mimicry programs and the demise of glioblastoma cells. Menin inhibition is being tested in clinical trials for blood malignancies (NCT04067336). Our preclinical work therefore reveals a novel and central role for macroH2A2 in an epigenetic network of stemness and suggests new clinical approaches for glioblastoma.

scholarly journals Determinants of adenine-mutagenesis in diversity-generating retroelements

2020 ◽  
Author(s):  
Sumit Handa ◽  
Andres Reyna ◽  
Timothy Wiryaman ◽  
Partho Ghosh
Keyword(s):  
Amino Acids ◽  
Dark Matter ◽  
Reverse Transcription ◽  
Genetic Information ◽  
Human Microbiome ◽  
Protein Sequences ◽  
Catalytic Efficiency ◽  
Natural World ◽  
In Vitro System

Abstract Diversity-generating retroelements (DGRs) vary protein sequences to the greatest extent known in the natural world. These elements are encoded by constituents of the human microbiome and the microbial ‘dark matter’. Variation occurs through adenine-mutagenesis, in which genetic information in RNA is reverse transcribed faithfully to cDNA for all template bases but adenine. We investigated the determinants of adenine-mutagenesis in the prototypical Bordetella bacteriophage DGR through an in vitro system composed of the reverse transcriptase bRT, Avd protein, and a specific RNA. We found that the catalytic efficiency for correct incorporation during reverse transcription by the bRT-Avd complex was strikingly low for all template bases, with the lowest occurring for adenine. Misincorporation across a template adenine was only somewhat lower in efficiency than correct incorporation. We found that the C6, but not the N1 or C2, purine substituent was a key determinant of adenine-mutagenesis. bRT-Avd was insensitive to the C6 amine of adenine but recognized the C6 carbonyl of guanine. We also identified two bRT amino acids predicted to nonspecifically contact incoming dNTPs, R74 and I181, as promoters of adenine-mutagenesis. Our results suggest that the overall low catalytic efficiency of bRT-Avd is intimately tied to its ability to carry out adenine-mutagenesis.

scholarly journals Lysine methyltransferase inhibitors: where we are now.

2022 ◽  
Author(s):  
Alessandra Feoli ◽  
Monica Viviano ◽  
Alessandra Cipriano ◽  
Ciro Milite ◽  
Sabrina Castellano ◽  
...  
Keyword(s):  
Large Family ◽  
Methyl Group ◽  
Lysine Methyltransferase ◽  
Lysine Methyltransferases

Protein lysine methyltransferases constitute a large family of epigenetic writers which catalyse the transfer of a methyl group from the cofactor S-adenosyl-L-methionine to histone and non-histone specific substrates. Alterations in...

scholarly journals Eaf1 Links the NuA4 Histone Acetyltransferase Complex to Htz1 Incorporation and Regulation of Purine Biosynthesis

2015 ◽  
Vol 14 (6) ◽  
pp. 535-544 ◽  
Author(s):  
Xue Cheng ◽  
Andréanne Auger ◽  
Mohammed Altaf ◽  
Simon Drouin ◽  
Eric Paquet ◽  
...  
Keyword(s):  
Gene Expression ◽  
Cross Talk ◽  
Global Gene Expression ◽  
Histone Variant ◽  
Purine Biosynthesis ◽  
Expression Array ◽  
Link Type ◽  
Molecular Events ◽  
Nucleosome Disassembly

ABSTRACT Proper modulation of promoter chromatin architecture is crucial for gene regulation in order to precisely and efficiently orchestrate various cellular activities. Previous studies have identified the stimulatory effect of the histone-modifying complex NuA4 on the incorporation of the histone variant H2A.Z (Htz1) at the PHO5 promoter (A. Auger, L. Galarneau, M. Altaf, A. Nourani, Y. Doyon, R. T. Utley, D. Cronier, S. Allard, and J. Côté, Mol Cell Biol 28:2257–2270, 2008, http://dx.doi.org/10.1128/MCB.01755-07 ). In vitro studies with a reconstituted system also indicated an intriguing cross talk between NuA4 and the H2A.Z-loading complex, SWR-C (M. Altaf, A. Auger, J. Monnet-Saksouk, J. Brodeur, S. Piquet, M. Cramet, N. Bouchard, N. Lacoste, R. T. Utley, L. Gaudreau, J. Côté, J Biol Chem 285:15966–15977, 2010, http://dx.doi.org/10.1074/jbc.M110.117069 ). In this work, we investigated the role of the NuA4 scaffold subunit Eaf1 in global gene expression and genome-wide incorporation of Htz1. We found that loss of Eaf1 affects Htz1 levels mostly at the promoters that are normally highly enriched in the histone variant. Analysis of eaf1 mutant cells by expression array unveiled a relationship between NuA4 and the gene network implicated in the purine biosynthesis pathway, as EAF1 deletion cripples induction of several ADE genes. NuA4 directly interacts with Bas1 activation domain, a key transcription factor of adenine genes. Chromatin immunoprecipitation (ChIP) experiments demonstrate that nucleosomes on the inactive ADE17 promoter are acetylated already by NuA4 and enriched in Htz1. Upon derepression, these poised nucleosomes respond rapidly to activate ADE gene expression in a mechanism likely reminiscent of the PHO5 promoter, leading to nucleosome disassembly. These detailed molecular events depict a specific case of cross talk between NuA4-dependent acetylation and incorporation of histone variant Htz1, presetting the chromatin structure over ADE promoters for subsequent chromatin remodeling and activated transcription.

Elucidation of the full genetic information of Japanese rubella vaccines and the genetic changes associated with in vitro and in vivo vaccine virus phenotypes

Vaccine ◽  
2011 ◽  
Vol 29 (10) ◽  
pp. 1863-1873 ◽  
Author(s):  
Noriyuki Otsuki ◽  
Hitoshi Abo ◽  
Toru Kubota ◽  
Yoshio Mori ◽  
Yukiko Umino ◽  
...  
Keyword(s):  
Genetic Information ◽  
Vaccine Virus ◽  
Genetic Changes

An Assay for Measuring Histone Variant Exchange within Nucleosomes In Vitro

2016 ◽  
pp. 19-37
Author(s):  
Liette Laflamme ◽  
Benoit Guillemette ◽  
Luc Gaudreau
Keyword(s):  
Histone Variant

Some effects of treatment of hen erythrocytes in vitro with N-methyl-N-nitrosourea

1981 ◽  
Vol 51 (1) ◽  
pp. 153-162
Author(s):  
T.H. Ward ◽  
R.F. Itzhaki
Keyword(s):  
Metabolic Activity ◽  
Cell Types ◽  
Condensed State ◽  
Methylation Site ◽  
Histone Proteins ◽  
Chromatin Proteins

Studies have been made of the effect of N-methyl-N-nitrosourea on hen erythrocytes in vitro. These were done to find whether the highly condensed state of the chromatin and the very low metabolic activity of these cells would affect the extent of methylation of the DNA and chromatin proteins and the persistence of any methylation sites in these macromolecules with time after treatment. Also, the effect of methylnitrosourea on incorporation of [3H] uridine into RNA has been examined. It has been found that the DNA, histones and non-histone proteins are methylated. The main methylation site in DNA is 7-methylguanine and its level is higher than that found by others in the DNA of other cell types after treatment with methylnitrosourea; however, methylation of the two types of protein (especially the histones) is relatively very low. The level of methylation decreases in the DNA and the chromatin proteins with time after treatment. The amount of [3H] uridine in RNA was found to decrease after the treatment.

scholarly journals Protein lysine 43 methylation by EZH1 promotes AML1-ETO transcriptional repression in leukemia

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Liping Dou ◽  
Fei Yan ◽  
Jiuxia Pang ◽  
Dehua Zheng ◽  
Dandan Li ◽  
...  
Keyword(s):  
Dna Sequences ◽  
Transcriptional Repression ◽  
Lysine Methylation ◽  
Post Translational Modification ◽  
Histone Lysine Methylation ◽  
Histone Lysine ◽  
Histone Lysine Methyltransferase ◽  
Lysine Methyltransferase

Abstract The oncogenic fusion protein AML1-ETO retains the ability of AML1 to interact with the enhancer core DNA sequences, but blocks AML1-dependent transcription. Previous studies have shown that post-translational modification of AML1-ETO may play a role in its regulation. Here we report that AML1-ETO-positive patients, with high histone lysine methyltransferase Enhancer of zeste homolog 1 (EZH1) expression, show a worse overall survival than those with lower EZH1 expression. EZH1 knockdown impairs survival and proliferation of AML1-ETO-expressing cells in vitro and in vivo. We find that EZH1 WD domain binds to the AML1-ETO NHR1 domain and methylates AML1-ETO at lysine 43 (Lys43). This requires the EZH1 SET domain, which augments AML1-ETO-dependent repression of tumor suppressor genes. Loss of Lys43 methylation by point mutation or domain deletion impairs AML1-ETO-repressive activity. These findings highlight the role of EZH1 in non-histone lysine methylation, indicating that cooperation between AML1-ETO and EZH1 and AML1-ETO site-specific lysine methylation promote AML1-ETO transcriptional repression in leukemia.

scholarly journals Intrinsic elasticity of nucleosomes is encoded by histone variants and calibrated by their binding partners

2019 ◽  
Vol 116 (48) ◽  
pp. 24066-24074 ◽  
Author(s):  
Daniël P. Melters ◽  
Mary Pitman ◽  
Tatini Rakshit ◽  
Emilios K. Dimitriadis ◽  
Minh Bui ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Chromosome Segregation ◽  
Binding Proteins ◽  
Histone Variants ◽  
Histone Variant ◽  
Binding Partners ◽  
Damage Repair ◽  
Fine Tune

Histone variants fine-tune transcription, replication, DNA damage repair, and faithful chromosome segregation. Whether and how nucleosome variants encode unique mechanical properties to their cognate chromatin structures remains elusive. Here, using in silico and in vitro nanoindentation methods, extending to in vivo dissections, we report that histone variant nucleosomes are intrinsically more elastic than their canonical counterparts. Furthermore, binding proteins, which discriminate between histone variant nucleosomes, suppress this innate elasticity and also compact chromatin. Interestingly, when we overexpress the binding proteins in vivo, we also observe increased compaction of chromatin enriched for histone variant nucleosomes, correlating with diminished access. Taken together, these data suggest a plausible link between innate mechanical properties possessed by histone variant nucleosomes, the adaptability of chromatin states in vivo, and the epigenetic plasticity of the underlying locus.

scholarly journals Deficiency of G9a Inhibits Cell Proliferation and Activates Autophagy via Transcriptionally Regulating c-Myc Expression in Glioblastoma

2020 ◽  
Vol 8 ◽  
Author(s):  
Xiao Xue Ke ◽  
Rui Zhang ◽  
Xi Zhong ◽  
Lei Zhang ◽  
Hongjuan Cui
Keyword(s):  
Cell Proliferation ◽  
Cyclin B1 ◽  
Luciferase Reporter ◽  
Cycle Arrest ◽  
Histone Lysine Methyltransferase ◽  
Lysine Methyltransferase ◽  
A Cell ◽  
Cell Proliferation Control

Glioblastoma is an aggressive and difficult to treat cancer. Recent data have emerged implicating that histone modification level may play a crucial role in glioma genesis. The histone lysine methyltransferase G9a is mainly responsible for the mono- and di-methylation of histone H3 lysine 9 (H3K9), whose overexpression is associated with a more aggressive phenotype in cancer. However, the detailed correlations between G9a and glioblastoma genesis remain to be further elucidated. Here, we show that G9a is essential for glioblastoma carcinogenesis and reveal a probable mechanism of it in cell proliferation control. We found that G9a was highly expressed in glioblastoma cells, and knockdown or inhibition of G9a significantly repressed cell proliferation and tumorigenesis ability both in vitro and in vivo. Besides, knockdown or inhibition of G9a led to a cell cycle arrest in G2 phase, as well as decreased the expression of CDK1, CDK2, Cyclin A2, and Cyclin B1, while it induced the activation of autophagy. Further investigation showed that G9a deficiency induced cell proliferation suppression, and activation of autophagy was rescued by overexpression of the full-length c-Myc. Chromatin immunoprecipitation (ChIP) assay showed that G9a was enriched on the −2267 to −1949 region of the c-Myc promoter in LN-229 cells and the −1949 to −1630 region of the c-Myc promoter in U-87 MG cells. Dual-luciferase reporter assay showed that c-Myc promoter activity was significantly reduced after knockdown or inhibition of G9a. Our study shows that G9a controls glioblastoma cell proliferation by transcriptionally modulating oncogene c-Myc and provides insight into the capabilities of G9a working as a potential therapeutic target in glioblastoma.

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