scholarly journals A non-enzymatic function associated with a putative histone demethylase licenses epigenetic inheritance

2019 ◽  
Author(s):  
Gulzhan Raiymbek ◽  
Sojin An ◽  
Nidhi Khurana ◽  
Saarang Gopinath ◽  
Raymond Trievel ◽  
...  
Keyword(s):  
Histone Deacetylases ◽  
Catalytic Domain ◽  
Epigenetic Inheritance ◽  
Specific Pattern ◽  
Histone Demethylase ◽  
Enzymatic Process ◽  
Heterochromatin Formation ◽  
Enzymatic Function ◽  
Primary Mechanism ◽  
Genome Wide

ABSTRACTH3K9 methylation (H3K9me) specifies the establishment and maintenance of transcriptionally silent epigenetic states or heterochromatin. The enzymatic erasure of histone modifications is widely assumed to be the primary mechanism that resets epigenetic states during and after DNA replication. Here, we demonstrate that a putative histone-demethylase Epe1 in fission yeast, regulates epigenetic inheritance through a non-enzymatic process. Mutations that map to its putative catalytic domain disrupt its interaction with Swi6HP1 and heterochromatin specific pattern of localization without any requirement for enzymatic activity. Epe1 and Swi6HP1 form an inhibitory complex which displaces histone deacetylases from sites of heterochromatin formation. Sequence-specific recruitment of a histone deacetylase, Clr3 renders heterochromatin refractory to the anti-silencing functions of Epe1 and licenses the inheritance of epigenetic states in cis. Epigenetic inheritance solely depends on the read-write activity of the H3K9 methyltransferase Clr4 which competes with genome-wide nucleosome turnover processes in the absence of enzymatic erasure.

scholarly journals Genome-Wide Dynamics of SAPHIRE, an Essential Complex for Gene Activation and Chromatin Boundaries

2007 ◽  
Vol 27 (11) ◽  
pp. 4058-4069 ◽  
Author(s):  
Matthew Gordon ◽  
Derick G. Holt ◽  
Anil Panigrahi ◽  
Brian T. Wilhelm ◽  
Hediye Erdjument-Bromage ◽  
...  
Keyword(s):  
Target Genes ◽  
Gene Activation ◽  
Histone Demethylase ◽  
Ribosomal Protein Genes ◽  
Transcription Start ◽  
Highly Active ◽  
Enzymatic Function ◽  
Genome Wide ◽  
Boundary Regulation ◽  
Nucleosome Binding

ABSTRACT In this study, we characterize a four-protein nucleosome-binding complex from Schizosaccharomyces pombe, termed SAPHIRE, that includes two orthologs of human Lsd1, a histone demethylase. The SAPHIRE complex is essential for cell viability, whereas saphire mutants lacking key conserved catalytic residues are viable but thermosensitive, suggesting that SAPHIRE has both an important enzymatic function and an essential nonenzymatic function. SAPHIRE is present in (or adjacent to) particular heterochromatic loci and also in the transcription start site regions of many highly active polymerase II genes. However, ribosomal protein genes are notably SAPHIRE deficient. SAPHIRE promotes activation, as target genes are selectively attenuated in saphire mutants. Interestingly, saphire mutants display increased histone H3 lysine 4 dimethylation, a modification typically associated with euchromatin. SAPHIRE localization is dynamic, as activated genes rapidly acquire SAPHIRE. Furthermore, saphire mutants dramatically shift a heterochromatin-euchromatin boundary in Chr1, suggesting a novel role in boundary regulation.

scholarly journals An H3K9 methylation-dependent protein interaction regulates the non-enzymatic functions of a putative histone demethylase

eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
Gulzhan Raiymbek ◽  
Sojin An ◽  
Nidhi Khurana ◽  
Saarang Gopinath ◽  
Ajay Larkin ◽  
...  
Keyword(s):  
Protein Interaction ◽  
Histone Demethylase ◽  
H3k9 Methylation ◽  
Heterochromatin Formation ◽  
Protein Protein Interaction ◽  
Enzymatic Function ◽  
C Terminus ◽  
Jmjc Domain

H3K9 methylation (H3K9me) specifies the establishment and maintenance of transcriptionally silent epigenetic states or heterochromatin. The enzymatic erasure of histone modifications is widely assumed to be the primary mechanism that reverses epigenetic silencing. Here, we reveal an inversion of this paradigm where a putative histone demethylase Epe1 in fission yeast, has a non-enzymatic function that opposes heterochromatin assembly. Mutations within the putative catalytic JmjC domain of Epe1 disrupt its interaction with Swi6HP1 suggesting that this domain might have other functions besides enzymatic activity. The C-terminus of Epe1 directly interacts with Swi6HP1, and H3K9 methylation stimulates this protein-protein interaction in vitro and in vivo. Expressing the Epe1 C-terminus is sufficient to disrupt heterochromatin by outcompeting the histone deacetylase, Clr3 from sites of heterochromatin formation. Our results underscore how histone modifying proteins that resemble enzymes have non-catalytic functions that regulate the assembly of epigenetic complexes in cells.

scholarly journals Restricted epigenetic inheritance of H3K9 methylation

Science ◽  
2015 ◽  
Vol 348 (6230) ◽  
pp. 132-135 ◽  
Author(s):  
Pauline N. C. B. Audergon ◽  
Sandra Catania ◽  
Alexander Kagansky ◽  
Pin Tong ◽  
Manu Shukla ◽  
...  
Keyword(s):  
Dna Sequences ◽  
Histone H3 ◽  
Epigenetic Inheritance ◽  
Histone Demethylase ◽  
Epigenetic Mark ◽  
H3k9 Methylation ◽  
Silent Chromatin ◽  
Wild Type ◽  
Heterochromatin Formation ◽  
Posttranslational Histone Modifications

Posttranslational histone modifications are believed to allow the epigenetic transmission of distinct chromatin states, independently of associated DNA sequences. Histone H3 lysine 9 (H3K9) methylation is essential for heterochromatin formation; however, a demonstration of its epigenetic heritability is lacking. Fission yeast has a single H3K9 methyltransferase, Clr4, that directs all H3K9 methylation and heterochromatin. Using releasable tethered Clr4 reveals that an active process rapidly erases H3K9 methylation from tethering sites in wild-type cells. However, inactivation of the putative histone demethylase Epe1 allows H3K9 methylation and silent chromatin maintenance at the tethering site through many mitotic divisions, and transgenerationally through meiosis, after release of tethered Clr4. Thus, H3K9 methylation is a heritable epigenetic mark whose transmission is usually countered by its active removal, which prevents the unauthorized inheritance of heterochromatin.

scholarly journals Genome-Wide Identification and Genetic Variations of the Starch Synthase Gene Family in Rice

Plants ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 1154
Author(s):  
Hongjia Zhang ◽  
Seong-Gyu Jang ◽  
San Mar Lar ◽  
Ah-Rim Lee ◽  
Fang-Yuan Cao ◽  
...  
Keyword(s):  
Gene Family ◽  
Catalytic Domain ◽  
Amylose Content ◽  
Expression Patterns ◽  
Starch Synthase ◽  
Eating Quality ◽  
Segmental Duplications ◽  
Genome Wide ◽  
The Relationship

Starch is a major ingredient in rice, and the amylose content of starch significantly impacts rice quality. OsSS (starch synthase) is a gene family related to the synthesis of amylose and amylopectin, and 10 members have been reported. In the present study, a synteny analysis of a novel family member belonging to the OsSSIV subfamily that contained a starch synthase catalytic domain showed that three segmental duplications and multiple duplications were identified in rice and other species. Expression data showed that the OsSS gene family is involved in diverse expression patterns. The prediction of miRNA targets suggested that OsSS are possibly widely regulated by miRNA functions, with miR156s targeted to OsSSII-3, especially. Haplotype analysis exhibited the relationship between amylose content and diverse genotypes. These results give new insight and a theoretical basis for the improved amylose content and eating quality of rice.

scholarly journals SUV39 SET domains mediate crosstalk of heterochromatic histone marks

eLife ◽  
2021 ◽  
Vol 10 ◽  
Author(s):  
Alessandro Stirpe ◽  
Nora Guidotti ◽  
Sarah J Northall ◽  
Sinan Kilic ◽  
Alexandre Hainard ◽  
...  
Keyword(s):  
Structure Function ◽  
Fission Yeast ◽  
Catalytic Domain ◽  
Constitutive Heterochromatin ◽  
Histone H3 ◽  
H3k9 Methylation ◽  
Set Domain ◽  
Heterochromatin Formation ◽  
Heterochromatin Silencing ◽  
Genomic Regions

The SUV39 class of methyltransferase enzymes deposits histone H3 lysine 9 di- and trimethylation (H3K9me2/3), the hallmark of constitutive heterochromatin. How these enzymes are regulated to mark specific genomic regions as heterochromatic is poorly understood. Clr4 is the sole H3K9me2/3 methyltransferase in the fission yeast Schizosaccharomyces pombe, and recent evidence suggests that ubiquitination of lysine 14 on histone H3 (H3K14ub) plays a key role in H3K9 methylation. However, the molecular mechanism of this regulation and its role in heterochromatin formation remain to be determined. Our structure-function approach shows that the H3K14ub substrate binds specifically and tightly to the catalytic domain of Clr4, and thereby stimulates the enzyme by over 250-fold. Mutations that disrupt this mechanism lead to a loss of H3K9me2/3 and abolish heterochromatin silencing similar to clr4 deletion. Comparison with mammalian SET domain proteins suggests that the Clr4 SET domain harbors a conserved sensor for H3K14ub, which mediates licensing of heterochromatin formation.

scholarly journals Genome-wide and high-density CRISPR-Cas9 screens identify point mutations in PARP1 causing PARP inhibitor resistance

2017 ◽  
Author(s):  
Stephen J. Pettitt ◽  
Dragomir B. Krastev ◽  
Inger Brandsma ◽  
Amy Drean ◽  
Feifei Song ◽  
...  
Keyword(s):  
Catalytic Domain ◽  
Synthetic Lethality ◽  
Parp Inhibitor ◽  
Point Mutations ◽  
Underlying Mechanism ◽  
Parp Inhibitors ◽  
High Density ◽  
Single Amino Acid ◽  
Genome Wide ◽  
Amino Acid Mutations

AbstractPARP inhibitors (PARPi) target homologous recombination defective tumour cells via synthetic lethality. Genome-wide and high-density CRISPR-Cas9 “tag, mutate and enrich” mutagenesis screens identified single amino acid mutations in PARP1 that cause profound PARPi-resistance. These included PARP1 mutations outside of the DNA interacting regions of the protein, such as mutations in solvent exposed regions of the catalytic domain and clusters of mutations around points of contact between ZnF, WGR and HD domains. These mutations altered PARP1 trapping, as did a mutation found in a clinical case of PARPi resistance. These genetic studies reinforce the importance of trapped PARP1 as a key cytotoxic DNA lesion and suggest that interactions between non-DNA binding domains of PARP1 influence cytotoxicity. Finally, different mechanisms of PARPi resistance (BRCA1 reversion, PARP1, 53BP1, REV7 mutation) had differing effects on chemotherapy sensitivity, suggesting that the underlying mechanism of PARPi resistance likely influences the success of subsequent therapies.

scholarly journals Intergenerational epigenetic inheritance in reef-building corals

2018 ◽  
Author(s):  
Yi Jin Liew ◽  
Emily J. Howells ◽  
Xin Wang ◽  
Craig T. Michell ◽  
John A. Burt ◽  
...  
Keyword(s):  
Dna Methylation ◽  
Intergenerational Transmission ◽  
Epigenetic Inheritance ◽  
Cpg Methylation ◽  
Epigenetic Mechanisms ◽  
Transgenerational Inheritance ◽  
Genome Wide ◽  
Methylation Patterns ◽  
Hypermethylated Genes

MainThe notion that intergenerational or transgenerational inheritance operates solely through genetic means is slowly being eroded: epigenetic mechanisms have been shown to induce heritable changes in gene activity in plants1,2and metazoans1,3. Inheritance of DNA methylation provides a potential pathway for environmentally induced phenotypes to contribute to evolution of species and populations1–4. However, in basal metazoans, it is unknown whether inheritance of CpG methylation patterns occurs across the genome (as in plants) or as rare exceptions (as in mammals)4. Here, we demonstrate genome-wide intergenerational transmission of CpG methylation patterns from parents to sperm and larvae in a reef-building coral. We also show variation in hypermethylated genes in corals from distinct environments, indicative of responses to variations in temperature and salinity. These findings support a role of DNA methylation in the transgenerational inheritance of traits in corals, which may extend to enhancing their capacity to adapt to climate change.

Abstract P252: Loss of HMGB2 Induces Chromatin Remodeling and Hypertrophic Growth in Cardiomyocytes

2011 ◽  
Vol 109 (suppl_1) ◽  
Author(s):  
Sarah Franklin ◽  
Haodong Chen ◽  
Scherise Mitchell-Jordan ◽  
Shuxun Ren ◽  
Peipei Ping ◽  
...  
Keyword(s):  
Gene Expression ◽  
Mass Spectrometry ◽  
Chromatin Remodeling ◽  
Nuclear Dna ◽  
Specific Pattern ◽  
Altered Expression ◽  
Hypertrophic Growth ◽  
Knock Down ◽  
Genome Wide ◽  
Chromatin Structural

Nuclear DNA is packaged around the octameric nucleosome core particle, constituting the basic building block of chromatin. Non-nucleosome chromatin structural molecules have been shown to induce higher order packaging of DNA into structurally compact and inactive heterochromatin, or loosely packed and active euchromatin. These chromatin remodeling events are thought to establish a cell type specific pattern of gene expression. During the development of cardiac hypertrophy and failure, genes normally only expressed during development are re-activated. While a number of transcription factors involved in these changes in fetal gene expression have been identified, the means for genome-wide structural remodeling of DNA are unknown. To identify factors controlling genomic plasticity in cardiomyocytes, we used mass spectrometry to quantify chromatin-associated proteins from cardiac nuclei during stages of hypertrophy and failure in the mouse. Adult mice were subjected to cardiac pressure overload by transverse aortic constriction. Chromatin was fractionated from cardiac nuclei and DNA-bound proteins were acid extracted and analyzed by mass spectrometry. We measured chromatin occupancy patterns for >300 proteins during distinct stages of heart failure. To explore the isoform specific roles of individual chromatin structural proteins, we used siRNA to knock-down expression of two high mobility group proteins (HMGB1 and 2) exhibiting altered expression in the hypertrophic heart. Loss of HMGB2 (but not HMGB1) induced robust hypertrophic growth in cardiomyocytes. qRT-PCR analyses demonstrated that HMGB2 is responsible for some but not all changes in the fetal gene program (ANF increased 150% and SERCA decreased 20%, whereas α- and β-MHC were unchanged). To further explore the endogenous regions of the genome under control of HMGB2 packing, we performed microarrays following HMGB2 knockdown. Hypertrophy or HMGB2 knock-down induced global chromatin remodeling conducive to gene expression, as measured by histone post-translational modifications and the ratio of core to linker histones. These studies reveal a novel role of HMGB2 to inhibit hypertrophic growth and provide insights into general principles for genome-wide chromatin remodeling.

scholarly journals Selective targeting of TET catalytic domain promotes somatic cell reprogramming

2020 ◽  
Vol 117 (7) ◽  
pp. 3621-3626 ◽  
Author(s):  
Anup Kumar Singh ◽  
Bo Zhao ◽  
Xiuhua Liu ◽  
Xin Wang ◽  
Hongzhi Li ◽  
...  
Keyword(s):  
Somatic Cell ◽  
Catalytic Domain ◽  
Specific Binding ◽  
Screening Strategy ◽  
Cell Reprogramming ◽  
Promoter Regions ◽  
Somatic Cell Reprogramming ◽  
Enzymatic Function ◽  
Small Molecule Compound ◽  
Tet Enzymes

Ten-eleven translocation (TET) family enzymes (TET1, TET2, and TET3) oxidize 5-methylcytosine (5mC) and generate 5-hydroxymethylcytosine (5hmC) marks on the genome. Each TET protein also interacts with specific binding partners and partly plays their role independent of catalytic activity. Although the basic role of TET enzymes is well established now, the molecular mechanism and specific contribution of their catalytic and noncatalytic domains remain elusive. Here, by combining in silico and biochemical screening strategy, we have identified a small molecule compound, C35, as a first-in-class TET inhibitor that specifically blocks their catalytic activities. Using this inhibitor, we explored the enzymatic function of TET proteins during somatic cell reprogramming. Interestingly, we found that C35-mediated TET inactivation increased the efficiency of somatic cell programming without affecting TET complexes. Using high-throughput mRNA sequencing, we found that by targeting 5hmC repressive marks in the promoter regions, C35-mediated TET inhibition activates the transcription of the BMP-SMAD-ID signaling pathway, which may be responsible for promoting somatic cell reprogramming. These results suggest that C35 is an important tool for inducing somatic cell reprogramming, as well as for dissecting the other biological functions of TET enzymatic activities without affecting their other nonenzymatic roles.

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