• Proceedings of the Korea Contents Association Conference
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• 2012.05a
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• pp.133-134
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• 2012

후성유전은 DNA 염기서열이 변화하지 않고 DNA의 메틸화(methylation)및 히스톤 단백질의 변형(modification)등의 후천적 과정에 의해 유전자 발현이 조절되는 현상이다. 특히 DNA 메틸화 정도에 대한 분석은 후성유전을 이해하는 중요한 접근방법 중 하나이다. DNA 메틸화 패턴 분석을 위하여 노화관련 109개 유전자들의 단백질 상호작용 네트워크를 구축하였으며 -3000bp ~ +200bp 사이에 있는 DNA 염기서열 정보를 추출하여 기존에 알려진 메틸화 저항성 (Methylation resistant) 모티프를 네트워크로 구축하였다. 메틸화 모티프기반 단백질 네트워크에서는 기존 단백질 네트워크보다 더 복잡한 구조를 이루고 있었다. 이러한 구조는 동일한 메틸화 모티프들이 여러 유전자들의 활성을 조절할 것으로 추측되며 복잡한 모티프들을 분석하기 위한 방법으로 이용될 수 있을 것이다.

• Journal of Life Science
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• v.28 no.12
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• pp.1536-1544
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• 2018

Depression is a common, serious, and recurring mental disorder. The pathogenesis of depression involves many factors such as environmental factor, genetic factor and alteration of structure and function in neurobiological systems. Increasing evidence supports that epigenetic alteration may be associated with depression. The epigenetics is explained as the mechanisms by which environmental factor causes changes in chromatin structure and alters gene expression without changing DNA base sequence. DNA methylation and histone modification involving histone acetylation and methylation are the main epigenetic mechanisms. Animal studies have shown that stressful environment such as early life stress can leave persistent epigenetic marks in the genome, which alter gene expression and influence neural and behavioral function through adulthood. A potentially important gene in depression is brain-derived neurotrophic factor (BDNF). BDNF plays a central role in depression and antidepressant action. In studies of the rodent, exposure to stress at prenatal, postnatal, and adult stages alters BDNF expression through histone modification and DNA methylation of the BDNF gene which results in anxiety and depressive-like behavior. This review discusses recent advances in the study of the epigenetic mechanisms that contribute to depression, particularly histone modification and DNA methylation of the BDNF gene, that may help in the development of new targets for depression treatment.

• Development and Reproduction
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• v.15 no.4
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• pp.273-279
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• 2011

Epigenetic regulation is a phenomenon that changes the gene function without changing the underlying DNA sequences. Epigenetic status of chromosome is regulated by mechanisms such as histone modification, DNA modification, and RNAi silencing. In this review, we focused on histone methylation for epigenetic regulation in ES cells. Two antagonizing multiprotein complexes regulate methylation of histones to guide expression of genes in ES cells. The Polycomb repressive complex 2 (PRC2), including EED, EZH2, and SUZ12 as core factors, contributes to gene repression by increasing trimethylation of H3K27 (H3K27me3). In contrast, the Trithorax group (TrxG) complex including MLL is related to gene activation by making H3K4me3. PRC2 and TrxG accompany a variety of accessory proteins. Most prominent feature of epigenetic regulation in ES cells is a bivalent state in which H3K27me3 and H3K4me3 appear simultaneously. Concerted regulation of PRC2, TrxG complex, and H3K4- or H3K27-specific demethylases activate expression of pluripotency-related genes and suppress development-related genes in ES cells. Modified balance of the regulators also enables ES cells to efficiently differentiate to a variety of cells upon differentiating signals. More detailed insights on the epigenetic regulators and their action will lead us to better understanding and use of ES cells for future application.

• Journal of The Korean Society of Inherited Metabolic disease
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• v.12 no.1
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• pp.42-48
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• 2012

Pompe disease is a rare lysosomal glycogen storage disorder caused by a total or partial deficiency of the acid ${\alpha}$-glucosidase (GAA) enzyme due to the GAA gene mutations. The classic infantile form of Pompe disease is a rapidly progressive multi-organ disease with hypotonia, generalized muscle weakness, and hypertrophic cardiomyopathy, usually leading to death in the first 2 years of life. Enzyme replacement therapy with recombinant human GAA has been shown to be effective and subsequently yielded promising results. Here, we present clinical and genetic characteristics of three Korean non-classic infantile Pompe patients, and the short term efficacy of enzyme replacement therapy. Considering that enzyme replacement therapy can change the natural course of infantile Pompe disease, early diagnosis and early initiation of treatment is critical to improving patient outcomes.

• 대한생식의학회:학술대회논문집
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• 1999.05a
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• pp.45-52
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• 1999

포유동물의 수정은 정자가 난자내로 침입함으로써 시작되는데 이때 정자는 부계의 유전물질 이외에도 다양한 후성적 요소들 (epigenetic factors), 즉 난활성 인자, 중심체, 부계 유래의 mitochondria 및 부계 특이 삽입 유전자 등을 난자에 전달해 준다. 하지만 수정 및 초기 배발달동안 정자에 의해 전달된 후성적 요소들의 역할과 기능적 발현 및 억제 기전에 관해서는 명확히 알려져 있지 않다. 수정보조기법인 ICSI 및 ROSI의 개발은 남성불임치료에 혁신적인 기술로 자리잡고 있을 뿐만 아니라 포유동물의 수정과정을 이해 하는데 많은 도움을 주고 있다. 본 연구실에서는 최근 몇 년간 돼지난자에 정자, 다양한 정자 구성 요소들, 정낭세포, 및 이종의 정자 등을 미세주입하여 수정을 유도한 후 핵질 및 세포질의 변화과정과 배 발달과정을 살펴 봄으로써, 수정시 정자에 의해 전달되는 후성적 요소들의 기능과 발현 기작을 규명하고자 하였다. 이러한 연구의 결과들은 체외수정, ICSI, ROSI 등의 임상치료기술의 개선에 기초자료로 활용될 수 있으리라 생각한다.

• Smart Media Journal
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• v.2 no.4
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• pp.34-40
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• 2013

Rapid sequencing of individual genomes with next generation sequencer opens new horizon to biology and personalized medicine. The analyzed sequences help to check several genomic abnormality, genomic expression, epigenomic phenotypes, gene annotation after assembly of their reads. Several trials integrating genomic information and clinical data will assist disease diagnostics and clinical treatments. To have a large step towards individualized medicine, development of smart interface linking specialized sequence data to the public is necessary.

• Journal of Life Science
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• v.34 no.7
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• pp.520-530
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• 2024

Tumor suppressor genes (TSGs) play a crucial role in maintaining cellular homeostasis. When the function of these genes is lost, it can lead to cellular plasticity that drives the development of various cancers, including small-cell lung cancer (SCLC), which is known for its aggressive nature. SCLC is primarily driven by numerous loss-of-function mutations in TSGs, often involving genes that encode epigenetic regulators. These mutations pose a significant therapeutic challenge as they are not directly targetable. However, understanding the molecular changes resulting from these mutations might provide insights for developing tumor intervention strategies. We propose that despite the heterogeneous genomic landscape of SCLC, the effects of mutations in patient tumors converge on a few critical pathways that drive malignancy. Specifically, alterations in epigenetic regulators lead to transcriptional dysregulation, pushing mutant cells toward a highly plastic state that makes them immune evasive and highly metastatic. This review will highlight studies showing how an imbalance of epigenetic regulators with opposing functions leads to the loss of immune recognition markers, effectively hiding tumor cells from the immune system. Additionally, we will discuss the role of epigenetic regulators in maintaining neuroendocrine features and how aberrant transcriptional control promotes epithelial-to-mesenchymal transition during tumor development. Although these pathways seem distinct, we emphasize that they often share common molecular drivers and mediators. Understanding the connection among frequently altered epigenetic regulators will provide valuable insights into the molecular mechanisms underlying SCLC development, potentially revealing preventive and therapeutic vulnerabilities for SCLC and other cancers with similar mutations.

• Journal of Life Science
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• v.29 no.9
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• pp.1002-1009
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• 2019

Early life stress (ELS) increases the risk of depression. ELS may be involved in the susceptibility to subsequent stress exposure during adulthood. We investigated whether epigenetic mechanisms of p11 promoter affect the vulnerability to chronic unpredictable stress (CUS) induced by the maternal separation (MS). Mice pups were separated from their dams (3 hr/day from P1-P21). When the pups reached adulthood, we applied CUS (daily for 3 weeks). The levels of hippocampal p11 expression were analyzed by quantitative real-time PCR. The levels of acetylated and methylated histone H3 at p11 promoter were measured by chromatin immunoprecipitation. Depression-like behavior was measured by the forced swimming test (FST). The MS and CUS group exhibited significant decreases in p11 mRNA level and the MS plus CUS group had a greater reduction in this level than the CUS group. The MS plus CUS group also resulted in greater reduction in H3 acetylation than the CUS group. This reduction was associated with an upregulation of histone deacetylase 5. Additionally, the MS plus CUS group showed a greater decrease in H3K4met3 level and a greater increase in H3K27 met3 level than the CUS group. Consistent with the reduction of p11 expression, the MS plus CUS group displayed longer immobility times in the FST compared to the control group. Mice exposed to MS followed by CUS had much greater epigenetic alterations in the hippocampus compared to adult mice that only experienced CUS. ELS can exacerbate the effect of stress exposure during adulthood through histone modification of p11 gene.

• Horticultural Science & Technology
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• v.32 no.3
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• pp.366-374
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• 2014

The study was conducted to investigate the possibility that epigenetic DNA methylation causes tree phenotypic variation in autotetraploids through evaluating the phenotypic variation and DNA methylation in autotetraploids occurred spontaneously from diploid trifoliate orange. Chromosome analysis confirmed that fourteen trifoliate orange trees of selected by flow cytometry were tetraploids (2n = 4X = 36) without any aneuploids. Chromomycin A3 staining determined that these trees were all autotetraploid with doubled chromosome set. Tree phenotypes, such as tree height and width, branching number, length, and angle, internode length, and leaf characteristics, varied in the autotetraploids. Chlorophyll indices were diverse in the autotetraploids, but photosynthetic rates were not significantly different. In addition, a wide range of variation was observed in stomatal density and guard cell length. Analysis of global cytosine DNA methylation showed that there was a variation of the methylation level in autotetraploids. More than half of 14 autotetraploids had at least 2 times higher methylation level than diploid trifoliate orange. The results indicate that tree phenotypic variation in autotetraploids might be related to global DNA methylation for reducing gene redundancy.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.47 no.2
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• pp.107-121
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• 2021

Skin hypopigmentation, which is observed in albinism or vitiligo, occurs when melanin synthesis is decreased by genetic, epigenetic, and other factors. To identify drug candidates that can promote melanin synthesis in cells, we screened an epigenetic modulator library consisting of 141 cell-permeable, small molecule drugs. B16/F10 murine melanoma cells were treated with each drug at 0.1 𝜇M and melanin synthesis and cell viability were subsequently monitored. As a result, (-)-neplanocin A, 3-deazaneplanocin A (DZNep), and DZNep hydrochloride were found to increase cellular melanin synthesis without causing cytotoxicity. Because these three structurally related drugs exhibited similar dose-dependent effects on melanin synthesis and cell viability, DZNep was selected as a representative drug for additional experiments. DZNep increased intracellular melanin content and tyrosinase (TYR) activity. DZNep also induced the expression of TYR, tyrosinase-related protein 1 (TYRP1), and dopachrome tautomerase (DCT) at the mRNA and protein levels. DZNep also induced the mRNA and protein expression of microphthalmia-associated transcription factor (MITF), a key regulator of melanin synthesis. DZNep is a specific inhibitor of S-adenosylhomocysteine hydrolase and it caused the accumulation of S-adenosylhomocysteine that inhibits histone methyltransferases in cells. This study suggests that melanogenesis can be modulated by targeting S-adenosylhomocysteine hydrolase in certain cellular contexts.