• The Plant Pathology Journal
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• 제33권2호
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• pp.193-205
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• 2017

Histone methylation plays important roles in regulating chromatin dynamics and transcription in eukaryotes. Implication of histone modifications in fungal pathogenesis is, however, beginning to emerge. Here, we report identification and functional analysis of a putative JmjC-domain-containing histone demethylase in Magnaporthe oryzae. Through bioinformatics analysis, we identified seven genes, which encode putative histone demethylases containing JmjC domain. Deletion of one gene, MoJMJ1, belonging to JARID group, resulted in defects in vegetative growth, asexual reproduction, appressorium formation as well as invasive growth in the fungus. Western blot analysis showed that global H3K4me3 level increased in the deletion mutant, compared to wild-type strain, indicating histone demethylase activity of MoJMJ1. Introduction of MoJMJ1 gene into ${\Delta}Mojmj1$ restored defects in pre-penetration developments including appressorium formation, indicating the importance of histone demethylation through MoJMJ1 during infection-specific morphogenesis. However, defects in penetration and invasive growth were not complemented. We discuss such incomplete complementation in detail here. Our work on MoJMJ1 provides insights into H3K4me3-mediated regulation of infection-specific development in the plant pathogenic fungus.

• 한국식품영양과학회지
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• 제46권2호
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• pp.169-176
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• 2017

본 연구에서는 쓴메밀 새싹 추출물(TBS)을 대상으로 histone acetyltransferase(HAT) 활성 저해능을 평가하고 oleic acid와 palmitic acid(OPA)를 이용하여 HepG2 세포에서 비알코올성 지방간을 유도하여 그 효과를 검토하였다. HeLa 세포의 nuclear extract(NE)를 HAT의 source로 하여 in vitro에서 TBS에 의한 HAT 활성 저해능을 평가한 결과 추출물의 처리에 의하여 HAT 활성이 억제됨을 관찰할 수 있었다. 또한, 대표적인 HAT 단백질인 p300과 CBP를 이용하여 동일한 방식으로 HAT 억제능을 평가한 결과 TBS 처리에 의하여 두 단백질 모두 활성이 감소하였으며, 특히 TBS는 p300의 활성을 특이적으로 저해함을 확인할 수 있었다. 그뿐만 아니라 HepG2 세포에 $400{\mu}M$의 oleic acid 및 $100{\mu}M$의 palmitic acid와 함께 $200{\mu}g/mL$, $500{\mu}g/mL$의 TBS를 처리한 후 NE를 이용하여 세포 내 HAT 활성을 측정한 결과 역시 추출물 처리에 의하여 세포 내 HAT 활성이 저해되어 있음이 관찰되었다. TBS에 의한 HAT 활성의 억제는 세포 내 다양한 단백질들의 아세틸화 저해와 지질축적에 의하여 아세틸화 변형을 일으키는 것으로 알려진 histone H3K9, H4K8의 아세틸화 및 H3K36의 아세틸화를 감소시켰으며, 세포 내 지질합성과 관련된 대표적 유전자인 SREBP1c, ACLY, FAS의 전사 활성 역시 저해함을 관찰하였다. 이와 같은 변화를 통하여 OPA에 의하여 HepG2 세포 내에 축적되었던 지질은 TBS의 처리에 의하여 효과적으로 감소하였으며 이때 처리된 OPA와 소재에 의한 세포 내 독성은 관찰되지 않았다. 그러므로 이러한 결과는 TBS에 의한 HAT 활성의 저해가 히스톤 단백질의 아세틸활 변형을 억제하고 이를 통하여 지방 합성 관련 유전자들의 전사 활성을 감소시켜 결과적으로 세포 내 지질축적을 방지하는 것으로 생각되며, TBS은 비알코올성 지방간질환의 예방에 좋은 천연물 소재로 활용될 수 있을 것이라 여겨진다.

• Molecules and Cells
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• 제42권7호
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• pp.530-545
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• 2019

Tumor cells can vary epigenetically during ionizing irradiation (IR) treatment. These epigenetic variegations can influence IR response and shape tumor aggressiveness. However, epigenetic disturbance of histones after IR, implicating in IR responsiveness, has been elusive. Here, we investigate whether altered histone modification after IR can influence radiation responsiveness. The oncogenic CXCL12 mRNA and protein were more highly expressed in residual cancer cells from a hepatoma heterotopic murine tumor microenvironment and coculture of human hepatoma Huh7 and normal IMR90 cells after radiation. H3K4 methylation was also enriched and H3K9 methylation was decreased at its promoter region. Accordingly, invasiveness and the subpopulation of aggressive $CD133^+/CD24^-$ cells increased after IR. Histone demethylase inhibitor IOX1 attenuated CXCL12 expression and the malignant subpopulation, suggesting that responses to IR can be partially mediated via histone modifications. Taken together, radiation-induced histone alterations at the CXCL12 promoter in hepatoma cells are linked to CXCL12 upregulation and increased aggressiveness in the tumor microenvironment.

• Molecules and Cells
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• 제38권6호
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• pp.580-586
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• 2015

While increasing evidence indicates the important function of histone methylation during development, how this process influences cardiac development in vertebrates has not been explored. Here, we elucidate the functions of two histone H3 lysine 4 (H3K4) methylation enzymes, SMYD3 and SETD7, during zebrafish heart morphogenesis using gene expression profiling by whole mount in situ hybridization and antisense morpholino oligonucleotide (MO)-based gene knockdown. We find both smyd3 and setd7 are highly expressed within developing zebrafish heart and knock-down of these genes led to severe defects in cardiac morphogenesis without altering the expressions pattern of heart markers, including cmlc2, vmhc, and amhc. Furthermore, double knock-down by coinjection of smyd3 and setd7 MOs caused the synergistic defects in heart development. As similar to knock-down effect, overexpression of these genes also caused the heart morphogenesis defect in zebrafish. These results indicate that histone modifying enzymes, SMYD3 and SETD7, appear to function synergistically during heart development and their proper functioning is essential for normal heart morphogenesis during development.

• Food Science and Biotechnology
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• 제16권3호
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• pp.457-462
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• 2007

Histone acetyltransferase (HAT) is a family of enzymes that regulate histone acetylation. Dysfunction of HAT plays a critical role in the development of cancer. Here we have screened the various plant extracts to find out the potent HAT inhibitors. The bellflower (Platycodon grandiflorum) root have exhibited approximately 30% of the inhibitory effects on HAT activity, especially p300 and CBP (CREB-binding protein) at the concentration of $100\;{\mu}g/mL$. The cell viability was decreased approximately 52% in LNCaP cell for 48 hr incubation. Furthermore, mRNA level of 3 androgen receptor target genes, PSA, NKX3.1, and TSC22 were decreased with bellflower root extract treatment ($100\;{\mu}g/mL$) in the presence of androgen. In ChIP assay, the acetylation of histone H3 and H4 in PSA promoter region was dramatically repressed by bellflower root treatment, but not TR target gene, Dl. Therefore, the potent HAT inhibitory effect of bellflower root led to the decreased transcription of AR target genes and prostate cancer cell growth with the repression of histone hyperacetylation.

• 한국발생생물학회지:발생과생식
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• 제15권4호
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• pp.273-279
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• 2011

후성유전학적 조절은 DNA 서열상의 변화 없이도 유전자의 기능을 변화시킬 수 있는 현상을 뜻한다. 염색체의 후성유전학적 상태는 히스톤 변형, DNA 변형 그리고 RNAi에 의한 유전자 침묵 등에 의해 조절된다. 본 총설에서는 배아줄기세포에서의 후성 유전학적 조절에 영향을 주는 요인으로서 히스톤(histone)의 메틸화에 초점을 맞추었다. 배아줄기세포에서 발현되는 유전자의 조절에는 두 가지 단백질 복합체가 관여한다. Polycomb repressive complex 2(PRC2)는 EED, EZH2, SUZ1를 주요인자로 포함하며, H3K27의 trimethylation(H3K27me3)을 증가시킴으로써 유전자의 발현을 억제한다. 이와는 대조적으로 Trithorax group(TrxG) 복합체는 주요인자로 MLL family를 포함하며, H3K4의 trimethylation(H3K4me3) 시킴으로써 유전자의 발현을 활성화한다. PRC2 및 TrxG는 다양한 보조 단백질을 포함한다. 배아줄기세포에서 후성유전학적 조절의 두드러진 특징은 H3K27me3과 H3K4me3이 동시에 나타나는 이가 상태(bivalent state)이다. PRC2와 TrxG 복합체 그리고 H3K4나 K3K27의 메틸화에 특이적으로 작용하는 탈메틸효소(demethylase)가 한데 어우러져 배아줄기세포에서 만능성 관련 유전자와 발달 관련 유전자의 발현을 조절함으로써 줄기세포의 유지 및 분화에 기여한다. 따라서 후성유전학적 조절인자들에 대한 보다 자세한 연구는 배아줄기세포를 보다 잘 이해하고 활용하는데 도움을 줄 것이다.

• Molecules and Cells
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• 제44권2호
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• pp.79-87
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• 2021

Chromatin dynamics is essential for maintaining genomic integrity and regulating gene expression. Conserved bromodomain-containing AAA+ ATPases play important roles in nucleosome organization as histone chaperones. Recently, the high-resolution cryo-electron microscopy structures of Schizosaccharomyces pombe Abo1 revealed that it forms a hexameric ring and undergoes a conformational change upon ATP hydrolysis. In addition, single-molecule imaging demonstrated that Abo1 loads H3-H4 histones onto DNA in an ATP hydrolysis-dependent manner. However, the molecular mechanism by which Abo1 loads histones remains unknown. Here, we investigated the details concerning Abo1-mediated histone loading onto DNA and the Abo1-DNA interaction using single-molecule imaging techniques and biochemical assays. We show that Abo1 does not load H2A-H2B histones. Interestingly, Abo1 deposits multiple copies of H3-H4 histones as the DNA length increases and requires at least 80 bp DNA. Unexpectedly, Abo1 weakly binds DNA regardless of ATP, and neither histone nor DNA stimulates the ATP hydrolysis activity of Abo1. Based on our results, we propose an allosteric communication model in which the ATP hydrolysis of Abo1 changes the configuration of histones to facilitate their deposition onto DNA.

• 미생물학회지
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• 제53권4호
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• pp.286-291
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• 2017

진핵 세포에서 히스톤의 변형은 크로마틴 구조를 조절하는 데에 있어서 중요한 메커니즘이다. Set1 복합체에 의한 히스톤 H3의 네 번째 라이신 잔기(H3K4)에 발생하는 메틸화는 다양하게 잘 알려져 있는 히스톤 변형 중 하나이다. Set1 complex는 H2B의 유비퀴틴화에 의존적으로 발생하는 H3K4 메틸화에 중요하다고 알려진 Swd2를 포함하여 7개의 소단위 단백질을 가지고 있다. Swd2는 Set1의 RNA recognition motif (RRM) 도메인 근처에 결합하여 Set1의 활성을 조절하고, 또 RNA의 3' 말단 형성에 관여하는 CPF (Cleavage and Polyadenylation Factors) 복합체의 구성성분이라고 보고되었다. 최근 보고들에 따르면, 이런 Swd2의 이중적인 기능이 서로 독립적으로 작용하며, Swd2 결실돌연변이 균주가 살지 못하는 이유가 CPF 복합체의 구성성분으로써의 기능 때문이라고 알려져 있다. 본 연구에서 우리는 Swd2가 Set1의 RRM 도메인에 결합하여 Set1의 활성을 조절할 수 있을 뿐만 아니라, Set1의 안정성에도 영향을 줄 수 있음을 발견하였다. 또 우리는 Swd2가 결합할 수 없는 truncated-Set1을 가지고 있는 ${\Delta}swd2$ 돌연변이가 사멸하지 않고 정상적으로 자라는 것을 관찰하였다. 이런 결과들은 Saccharomyces cerevisiae에서 H3K4 메틸화와 RNA 3' 말단 형성과정에서의 Swd2의 이중적인 기능이 서로 독립적인 것이 아님을 제안하다.

• 한국자원식물학회지
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• 제22권3호
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• pp.203-208
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• 2009

Lunasin is a unique 43-amino acid peptide which has shown a chemopreventive in mammalian cells and in a skin cancer mouse model. In search for new sources of lunasin and the role of cereals in cancer prevention, we report here the properties of lunasin purified from millet. Stability of millet lunasin was measured by in vitro digestibility assay using pepsin and pancreatin. Inhibition of HAT (histone acetyltransferase) and nuclear localization in mammalian cells were used to measure lunasin bioactivity as the cancer chemopreventive agent. Lunasin present in millet crude protein was stable to pepsin and pancreatin in in vitro digestion and inhibited the activities of HATs. When added exogenously, lunasin purified from millet internalized in the nuclei of mouse fibroblast cells. On the base of this result, we conclude that lunasin in millet is bioactive and consumption of millet may play an important role on cancer prevention in millet-consuming populations.

• Animal cells and systems
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• 제16권4호
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• pp.289-294
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• 2012

Histone methylation has diverse functions including transcriptional regulation via its lysine or arginine residue methylation. Studies indicate that deregulation of histone methylation is linked to human cancers including leukemia. Histone H3K27 methyltrnasferase response element II binding protein (RE-IIBP), as a transcriptional repressor to target gene IL-5, interacts with HDAC and is over-expressed in leukemia patient samples. In this study, we have identified that hematopoiesis-related genes GATA1 and HOXA9 are down-regulated by RE-IIBP in K562 and 293T cells. Transient reporter analysis revealed that GATA1 transcription was repressed by RE-IIBP. On the other hand, HOXA9 and PBX-related homeobox gene MEIS1 was up-regulated by RE-IIBP. These results suggest that RE-IIBP might have a role in hematopoiesis or leukemogenesis by regulating the transcription of target genes, possibly via its H3K27 methyltransferase activity.