• Molecules and Cells
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• v.27 no.4
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• pp.481-490
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• 2009

Diverse posttranslational modifications of histones, such as acetylation and methylation, play important roles in controlling gene expression. Histone methylation in particular is involved in a broad range of biological processes, including heterochromatin formation, X-chromosome inactivation, genomic imprinting, and transcriptional regulation. Recently, it has been demonstrated that proteins containing the Jumonji (Jmj) C domain can demethylate histones. In Arabidopsis, twenty-one genes encode JmjC domain-containing proteins, which can be clustered into five clades. To address the biological roles of the Arabidopsis genes encoding JmjC-domain proteins, we analyzed the temporal and spatial expression patterns of nine genes. RT-PCR analyses indicate all nine Arabidopsis thaliana Jmj (AtJmj) genes studied are actively expressed in various tissues. Furthermore, studies of transgenic plants harboring AtJmj::${\beta}$-glucuronidase fusion constructs reveal that these nine AtJmj genes are expressed in a developmentally and spatially regulated manner.

• Archives of Pharmacal Research
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• v.10 no.3
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• pp.193-196
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• 1987

Protein methylation occurs ubiquitously in nature and involves N-methylation of lysine, arginine, histidine, alanine, proline and glutamine, O-methylesterfication o dicarboxylic acids, and S-methylation of cysteine and methionine. In nature, methylated amino acids accur in highly specialized proteins such as histones, flagella proteins, myosin, actin, ribosomal proteins. hn RNA-bound protein, HMG-1 and HMG-2 protein, opsin, EF-Tu, EF-$1\alpha$, porcine heart citrate synthase, calmodulin, ferredoxin, $1\alpha$-amylase, heat shock protein, scleroderma antigen, nucleolar protein C23 and IF-3l.

• Journal of Pharmacopuncture
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• v.19 no.3
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• pp.195-196
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• 2016

• Animal cells and systems
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• v.9 no.2
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• pp.79-85
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• 2005

Oxidized abasic residues arise as a major class of DNA damage by a variety of agents involving free radical attack and oxidation of deoxyribose sugar components. 2-deoxyribonolactone (dL) is a C1'-oxidized abasic lesion implicated in DNA strand scission, mutagenesis, and covalent DNA-protein cross-link (DPC). We show here that mammalian cell-free extract give rise to stable DPC formation that is specifically mediated by dL residue. When a duplex DNA containing dL at the site-specific position was incubated with cell-free extracts of Po ${\beta}-proficient$ and -deficient mouse embryonic fibroblast cells, the formation of major dL-mediated DPC was dependent on the presence of DNA polymerase (Pol) ${\beta}$. Formation of dL-specific DPC was also observed with histones and FEN1 nuclease, although the reactivity in forming dL-mediated DPC was significantly higher with Pol ${\beta}$ than with histones or FEN1. DNA repair assay with a defined DPC revealed that the dL lesion once cross-linked with Pol ${\beta}$ was resistant to nucleotide excision repair activity of cell-free extract. Analysis of nucleotide excision repair utilizing a model DNA substrate containing a (6-4) photoproduct suggested that excision process for DPC was inhibited because of DNA single-strand incision at 5' of the lesion. Consequently DPC mediated by dL lesion may not be readily repaired by DNA excision repair pathway but instead function as unusual DNA damage causing a prolonged DNA strand break and trapping of the major base excision repair enzyme.

• Parasites, Hosts and Diseases
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• v.62 no.1
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• pp.98-116
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• 2024

Epigenetic writers including DNA and histone lysine methyltransferases (DNMT and HKMT, respectively) play an initiative role in the differentiation and development of eukaryotic organisms through the spatiotemporal regulation of functional gene expressions. However, the epigenetic mechanisms have long been suspected in helminth parasites lacking the major DNA methyltransferases DNMT1 and DNMT3a/3b. Very little information on the evolutionary status of the epigenetic tools and their role in regulating chromosomal genes is currently available in the parasitic trematodes. We previously suggested the probable role of a DNMT2-like protein (CsDNMT2) as a genuine epigenetic writer in a trematode parasite Clonorchis sinensis. Here, we analyzed the phylogeny of HKMT subfamily members in the liver fluke and other platyhelminth species. The platyhelminth genomes examined conserved genes for the most of SET domain-containing HKMT and Disruptor of Telomeric Silencing 1 subfamilies, while some genes were expanded specifically in certain platyhelminth genomes. Related to the high gene dosages for HKMT activities covering differential but somewhat overlapping substrate specificities, variously methylated histones were recognized throughout the tissues/organs of C. sinensis adults. The temporal expressions of genes involved in eggshell formation were gradually decreased to their lowest levels proportionally to aging, whereas those of some epigenetic tool genes were re-boosted in the later adult stages of the parasite. Furthermore, these expression levels were significantly affected by treatment with DNMT and HKMT inhibitors. Our data strongly suggest that methylated histones are potent epigenetic markers that modulate the spatiotemporal expressions of C. sinensis genes, especially those involved in sexual reproduction.

• Archives of Pharmacal Research
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• v.9 no.3
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• pp.157-161
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• 1986

Isolated calf thymus nuclei were in vitro methylated with S- adenosy-L-methyl-$^{14}C$ methionine, and the proteins were fractionated according to their solubilities. Histone fraction ($H_{2}SO_{4}$-soluble fraction) contained approximately 60% total radioactivity incorporated, while "residual protein" which was ($H_{2}SO_{4}$-insoluble contained the remaining radio-activity. The "residual protein" was further fractionated into various acidic proteins, which contained very littel of the radioactivity. However, the protein fraction eluted from DEAE-cellulose with 0.5 N NaOH contained the largest amount of radioactivity. This protein was found to be basic in nature by amino analysis.

• Genomics & Informatics
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• v.11 no.1
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• pp.7-14
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• 2013

As the International Human Epigenome Consortium (IHEC) launched officially at the 2010 Washington meeting, a giant step toward the conquest of unexplored regions of the human genome has begun. IHEC aims at the production of 1,000 reference epigenomes to the international scientific community for next 7-10 years. Seven member institutions, including South Korea, Korea National Institute of Health (KNIH), will produce 25-200 reference epigenomes individually, and the produced data will be publically available by using a data center. Epigenome data will cover from whole genome bisulfite sequencing, histone modification, and chromatin access information to miRNA-seq. The final goal of IHEC is the production of reference maps of human epigenomes for key cellular status relevant to health and disease.

• Biomolecules & Therapeutics
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• v.22 no.4
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• pp.308-313
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• 2014

Activator protein-1 (AP-1) is an inducible transcription factor that contributes to the generation of chronic inflammation in response to oxidative and electrophilic stress. Previous studies have demonstrated that the PI3K/Akt1 pathway plays an important role in the transcriptional regulation of AP-1 expression. Although the histone post-translational modifications (PTMs) are assumed to affect the AP-1 transcriptional regulation by the PI3K/Akt pathway, the detailed mechanisms are completely unknown. In the present study, we show that heterochromatin 1 gamma ($HP1{\gamma}$) plays a negative role in TPA-induced c-Jun and c-Fos expression. We show that TPA-induced Akt1 directly phosphorylates $HP1{\gamma}$, abrogates its suppressive function and increases the interaction between histone H3 and 14-3-$3{\varepsilon}$. Collectively, these our data illustrate that the activation of PI3K/Akt pathway may play a permissive role in the recruitment of histone readers or other coactivators on the chromatin, thereby affecting the degree of AP-1 transcription.

• Journal of Life Science
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• v.17 no.4 s.84
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• pp.593-598
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• 2007

Amino acids of histone tail are covalently modified in eukaryotic cells. Lysine residues in histone H3 and H4 are methylated at three levels; mono-, di- or trimethylation. Methylation in histones is related with transcription of the genes in distinct pattern depending on lysine residues and methylated levels. Relation between transcription and methylation has been relatively well understood at three lysines H3K4, H3K9 and H3K36. H3K4 is methylated in active or potentially active chromatin and its methylation associates with active transcription. H3K9 is generally methylated in heterochromatin or repressed gene, but trimethylation of this lysine occur in actively transcribed genes also. Methylation at H3K36 generally correlates with active chromatin/transcription, but the correlation of its dimethylation with transcription is controversial. All together methylation patterns of individual lysine residues in histone relate with activation or repression of transcription and may provide distinctive roles in transcriptional regulation of the eukaryotic genes.

• Molecules and Cells
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• v.26 no.3
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• pp.217-227
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• 2008

Heterochromatin protein 1 (HP1) was first described in Drosophila melanogaster as a heterochromatin associated protein with dose-dependent effect on gene silencing. The HP1 family is evolutionarily highly conserved and there are multiple members within the same species. The multi-functionality of HP1 reflects its ability to interact with diverse nuclear proteins, ranging from histones and transcriptional co-repressors to cohesion and DNA replication factors. As its name suggests, HP1 is well-known as a silencing protein found at pericentromeres and telomeres. In contrast to previous views that heterochromatin is transcriptionally inactive; noncoding RNAs transcribed from heterochromatic DNA repeats regulates the assembly and function of heterochromatin ranging from fission yeast to animals. Moreover, more recent progress has shed light on the paradoxical properties of HP1 in the nucleus and has revealed, unexpectedly, its existence in the euchromatin. Therefore, HP1 proteins might participate in both transcription repression in heterochromatin and euchromatin.