• Genomics & Informatics
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• 제16권3호
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• pp.65-70
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• 2018

The non-coding DNA in eukaryotic genomes encodes a language which programs chromatin accessibility, transcription factor binding, and various other activities. The objective of this short report was to determine the impact of primary DNA sequence on the epigenomic landscape across 200-base pair genomic units by integrating nine publicly available ChromHMM Browser Extensible Data files of the Encyclopedia of DNA Elements (ENCODE) project. The nucleotide frequency profiles of nine chromatin annotations with the units of 200 bp were analyzed and integrative Markov chains were built to detect the Markov properties of the DNA sequences in some of the active chromatin states of different ChromHMM regions. Our aim was to identify the possible relationship between DNA sequences and the newly built chromatin states based on the integrated ChromHMM datasets of different cells and tissue types.

• Molecules and Cells
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• 제28권3호
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• pp.149-154
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• 2009

Faithful and accurate replication of the DNA molecule is essential for eukaryote organisms. Nonetheless, in the last few years it has become evident that inheritance of the chromatin states associated with different regions of the genome is as important as the faithful inheritance of the DNA sequence itself. Such chromatin states are determined by a multitude of factors that act to modify not only the DNA molecule, but also the histone proteins associated with it. For instance, histones can be posttranslationally modified, and it is well established that these posttranslational marks are involved in several essential nuclear processes such as transcription and DNA repair. However, recent evidence indicates that posttranslational modifications of histones might be relevant during DNA replication. Hence, the aim of this review is to describe the most recent publications related to the role of histone posttranslational modifications during DNA replication.

• BMB Reports
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• 제52권3호
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• pp.175-180
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• 2019

Telomeres are nucleoprotein complexes at the physical ends of linear eukaryotic chromosomes. They protect the chromosome ends from various external attacks to avoid the loss of genetic information. Telomeres are maintained by cellular activities associated with telomerase and telomere-binding proteins. In addition, epigenetic regulators have pivotal roles in controlling the chromatin state at telomeres and subtelomeric regions, contributing to the maintenance of chromosomal homeostasis in yeast, animals, and plants. Here, we review the recent findings on chromatin modifications possibly associated with the dynamic states of telomeres in Arabidopsis thaliana.

• Genomics & Informatics
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• 제12권4호
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• pp.145-150
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• 2014

Recent technical advances, such as chromatin immunoprecipitation combined with DNA microarrays (ChIp-chip) and chromatin immunoprecipitation-sequencing (ChIP-seq), have generated large quantities of high-throughput data. Considering that epigenomic datasets are arranged over chromosomes, their analysis must account for spatial or temporal characteristics. In that sense, simple clustering or classification methodologies are inadequate for the analysis of multi-track ChIP-chip or ChIP-seq data. Approaches that are based on hidden Markov models (HMMs) can integrate dependencies between directly adjacent measurements in the genome. Here, we review three HMM-based studies that have contributed to epigenetic research, from a computational perspective. We also give a brief tutorial on HMM modelling-targeted at bioinformaticians who are new to the field.

• BMB Reports
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• 제40권2호
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• pp.135-141
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• 2007

Conjugation of the methyl group at the fifth carbon of cytosines within the palindromic dinucleotide 5'-CpG-3' sequence (DNA methylation) is the best studied epigenetic mechanism, which acts together with other epigenetic entities: histone modification, chromatin remodeling and microRNAs to shape the chromatin structure of DNA according to its functional state. The cancer genome is frequently characterized by hypermethylation of specific genes concurrently with an overall decrease in the level of 5-methyl cytosine, the pathological implication of which to the cancerous state has been well established. While the latest genome-wide technologies have been applied to classify and interpret the epigenetic layer of gene regulation in the physiological and disease states, the epigenetic testing has also been seriously explored in clinical practice for early detection, refining tumor staging and predicting disease recurrence. This critique reviews the latest research findings on the use of DNA methylation in cancer diagnosis, prognosis and staging/classification.

• Molecules and Cells
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• 제37권12호
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• pp.841-850
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• 2014

Polycomb group (PcG) proteins are conserved chromatin regulators involved in the control of key developmental programs in eukaryotes. They collectively provide the transcriptional memory unique to each cell identity by maintaining transcriptional states of developmental genes. PcG proteins form multi-protein complexes, known as Polycomb repressive complex 1 (PRC1) and Polycomb repressive complex 2 (PRC2). PRC1 and PRC2 contribute to the stable gene silencing in part through catalyzing covalent histone modifications. Components of PRC1 and PRC2 are well conserved from plants to animals. PcG-mediated gene silencing has been extensively investigated in efforts to understand molecular mechanisms underlying developmental programs in eukaryotes. Here, we describe our current knowledge on PcG-mediated gene repression which dictates developmental programs by dynamic layers of regulatory activities, with an emphasis given to the model plant Arabidopsis thaliana.

• 생명과학회지
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• 제17권3호통권83호
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• pp.381-385
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• 2007

FACT(facilitates chromatin transcription)은 크로마틴을 주형으로 하는 전사에 필요한 크로마틴 특이적 전사 진행 인자이다. FACT는 Saccharomyces Cerevisiae Spt16/Cdc68의인간 유사체와 high mobility froup-1-like protein structure-specific recognition protein-1(SSRP-1)의 이종단백질 복합체이다 본 논문에서는 FACT의 단위체인 hSpt16의 발현이 휴지기의 T98G 세포에서 급격히 감소됨을 면역형광 분석법과 Western blot 분석법을 이용하여 관찰하였다. 이와 반대로 증식기의 T98C 세포에서는 hSpt16이 높은 수준으로 발현되고 있는 것이 관찰되었다. FACT의 또 다른 단위체 SSRP-1의 발현은 휴지기나 증식기의 세포에서 변화가 없음이 관찰되었다. 이상의 결과로부터 hSpt16이 발현이 세포의증식과 연관이 되어 있음을 알 수 있었고 세포 증식 표지 인자로 사용될 수 있을 것으로 사료된다.

• Genomics & Informatics
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• 제13권4호
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• pp.152-155
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• 2015

Recently, the Encyclopedia of DNA Elements (ENCODE) Analysis Working Group converted data from ChIP-seq analyses from the Broad Histone track into 15 corresponding chromatic maps that label sequences with different kinds of histone modifications in promoter regions. Here, we publish a frequency profile of the three ChromHMM promoter states, at 200-bp intervals, with particular reference to the existence of sequence patterns of promoter elements, GC-richness, and transcription starting sites. Through detailed and diligent analysis of promoter regions, researchers will be able to uncover new and significant information about transcription initiation and gene function.

• Genomics & Informatics
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• 제20권1호
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• pp.2.1-2.11
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• 2022

The method of single-cell RNA sequencing has been rapidly developed, and numerous experiments have been conducted over the past decade. Their results allow us to recognize various subpopulations and rare cell states in tissues, tumors, and immune systems that are previously unidentified, and guide us to understand fundamental biological processes that determine cell identity based on single-cell gene expression profiles. However, it is still challenging to understand the principle of comprehensive gene regulation that determines the cell fate only with transcriptome, a consequential output of the gene expression program. To elucidate the mechanisms related to the origin and maintenance of comprehensive single-cell transcriptome, we require a corresponding single-cell epigenome, which is a differentiated information of each cell with an identical genome. This review deals with the current development of single-cell epigenomic library construction methods, including multi-omics tools with crucial factors and additional requirements in the future focusing on DNA methylation, chromatin accessibility, and histone post-translational modifications. The study of cellular differentiation and the disease occurrence at a single-cell level has taken the first step with single-cell transcriptome and is now taking the next step with single-cell epigenome.

• Current Research on Agriculture and Life Sciences
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• 제31권3호
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• pp.157-164
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• 2013

Chromatin remodelers that include histone methyl transferases (HMTases) are becoming a focal point in cancer drug development. The NSD family of three HMTases, NSD1, NSD2/MMSET/WHSC1, and NSD3/WHSC1L are bona fide oncogenes found aberrantly expressed in several cancers, suggesting their potential role for novel therapeutic strategies. Several histone modifiers including HMTase have clear roles in human carcinogenesis but the extent of their functions and regulations are not well understood, especially in pathological conditions. The extents of the NSDs biological roles in normal and pathological conditions remain unclear. In particular, the substrate specificity of the NSDs remains unsettled and discrepant data has been reported. NSD2/MMSET is a focal point for therapeutic interventions against multiple myeloma and especially for t(4;14) myeloma, which is associated with a significantly worse prognosis than other biological subgroups. Multiple myeloma is the second most common hematological malignancy in the United States, after non-Hodgkin lymphoma. Herein, as a first step before entering a pipeline for protein x-ray crystallography, we cloned, recombinantly expressed and purified the catalytic SET domain of NSD2. Next, we demonstrated the catalytic activities, in vitro, of the recombinantly expressed NSD2-SET on H3K36 and H4K20, its biological targets at the chromatin.