• 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.

• Molecules and Cells
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• 제37권10호
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• pp.734-741
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• 2014

Histone modifications on major transcription factor target genes are one of the major regulatory mechanisms controlling adipogenesis. Plant homeodomain finger 2 (PHF2) is a Jumonji domain-containing protein and is known to demethylate the histone H3K9, a repressive gene marker. To better understand the function of PHF2 in adipocyte differentiation, we constructed stable PHF2 knock-down cells by using the mouse pre-adipocyte cell line 3T3-L1. When induced with adipogenic media, PHF2 knock-down cells showed reduced lipid accumulation compared to control cells. Differential expression using a cDNA microarray revealed significant reduction of metabolic pathway genes in the PHF2 knock-down cell line after differentiation. The reduced expression of major transcription factors and adipokines was confirmed with reverse transcription- quantitative polymerase chain reaction and Western blotting. We further performed co-immunoprecipitation analysis of PHF2 with four major adipogenic transcription factors, and we found that CCATT/enhancer binding protein (C/EBP)${\alpha}$ and C/EBP${\delta}$ physically interact with PHF2. In addition, PHF2 binding to target gene promoters was confirmed with a chromatin immunoprecipitation experiment. Finally, histone H3K9 methylation markers on the PHF2-binding sequences were increased in PHF2 knock-down cells after differentiation. Together, these results demonstrate that PHF2 histone demethylase controls adipogenic gene expression during differentiation.

• BMB Reports
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• 제42권3호
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• pp.154-159
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• 2009

JARID1B (jumonji AT rich interactive domain 1B) is a large nuclear protein that is highly expressed in breast cancers and is proposed to function as a repressor of gene expression. In this paper, a phage display screen using the N-terminus of JARID1B as bait identified one of the JARID1B interacting proteins, namely PcG protein (Polycomb group) hPc2. We demonstrated that the C-terminal region, including the COOH box, was required for the interaction with the N-terminus of JARID1B. In a reporter assay system, co-expression of JARID1B with hPc2 significantly enhanced the transcriptional repression. These results support a role for hPc2 acting as a transcriptional co-repressor.

• BMB Reports
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• 제50권1호
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• pp.49-54
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• 2017

Previously, we reported that vitamin C facilitates the CpG demethylation of Foxp3 enhancer in $CD4^+Foxp3^+$ regulatory T cells (Tregs) by enhancing the activity of a DNA demethylase ten-eleven-translocation (Tet). However, it is not clear whether vitamin C affects other helper T cell lineages like T helper type 17 (Th17) cells which are related with Tregs. Here, we show that the expression of interleukin-17A (IL17) increases with the treatment of vitamin C but not with other antioxidants. Interestingly, the upregulation of IL17 was not accompanied by DNA demethylation in Il17 promoter and was independent of Tet enzymes. Rather, vitamin C reduced the trimethylation of histone H3 lysine 9 (H3K9me3) in the regulatory elements of the Il17 locus, and the effects of vitamin C were abrogated by knockdown of jumonji-C domain-containing protein 2 (jmjd2). These results suggest that vitamin C can affect the expression of IL17 by modulating the histone demethylase activity.

• 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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• 제37권1호
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• pp.43-50
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• 2014

Jumonji domain-containing proteins (JMJD) catalyze the oxidative demethylation of a methylated lysine residue of histones by using $O_2$, ${\alpha}$-ketoglutarate, vitamin C, and Fe(II). Several JMJDs are induced by hypoxic stress to compensate their presumed reduction in catalytic activity under hypoxia. In this study, we showed that an H3K27me3 specific histone demethylase, JMJD3 was induced by hypoxia-inducible factor (HIF)-$1{\alpha}/{\beta}$ under hypoxia and that treatment with Clioquinol, a HIF-$1{\alpha}$ activator, increased JMJD3 expression even under normoxia. Chromatin immunoprecipitation (ChIP) analyses showed that both HIF-$1{\alpha}$ and its dimerization partner HIF-$1{\beta}$/Arnt occupied the first intron region of the mouse JMJD3 gene, whereas the HIF-$1{\alpha}/{\beta}$ heterodimer bound to the upstream region of the human JMJD3, indicating that human and mouse JMJD3 have hypoxia-responsive regulatory regions in different locations. This study shows that both mouse and human JMJD3 are induced by HIF-1.

• Molecules and Cells
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• 제40권10호
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• pp.737-751
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• 2017

Histone-modifying enzymes are key players in the field of cellular differentiation. Here, we used GSK-J4 to profile important target genes that are responsible for neural differentiation. Embryoid bodies were treated with retinoic acid ($10{\mu}M$) to induce neural differentiation in the presence or absence of GSK-J4. To profile GSKJ4-target genes, we performed RNA sequencing for both normal and demethylase-inhibited cells. A total of 47 and 58 genes were up- and down-regulated, respectively, after GSK-J4 exposure at a log2-fold-change cut-off value of 1.2 (p-value < 0.05). Functional annotations of all of the differentially expressed genes revealed that a significant number of genes were associated with the suppression of cellular proliferation, cell cycle progression and induction of cell death. We also identified an enrichment of potent motifs in selected genes that were differentially expressed. Additionally, we listed upstream transcriptional regulators of all of the differentially expressed genes. Our data indicate that GSK-J4 affects cellular biology by inhibiting cellular proliferation through cell cycle suppression and induction of cell death. These findings will expand the current understanding of the biology of histone-modifying enzymes, thereby promoting further investigations to elucidate the underlying mechanisms.

• 생명과학회지
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• 제17권3호통권83호
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• pp.444-453
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• 2007

유핵세포의 게놈(genome)은 단백-DNA복합체인 염색질(chromatin)의 형태로 존재하는데, 생명현상을 유지하기 위해서는 생명체 또는 세포가 처한 상황에 맞게 염색질의 구조를 변화시키는 역동적인 조절기전이 필요하다. 염색질을 구성하는 기본단위는 히스톤 8량체 (histone octamer)를 포함하는 뉴클레오좀(nucleosome)이다. 히스톤 단백에는 여러 종류의 공유결합성 수식이 일어나는데, 그 중 하나가 라이신 잔기(lysine residue)에 일어나는 메틸화이다. 최근 수년간의 연구로 여러 개의 히스톤 라이신 메틸화효소(histone lysine methyltransferase, HKMT), 이에 결합하는 염색질단백 및 메틸화와 관련된 후생유전학적 현상이 밝혀졌으며, 특히 정밀한 연구방법을 동원한 다방면의 실험을 통하여 비록 자세한 기전과 전체적인 윤곽의 규명은 미흡하더라도 라이신 메틸화가 후생유전학적 변화를 초래하는 일부 과정이 규명 되었다. 또한 여러 종류의 라이신 탈메틸화효소가 최근에 발견됨에 따라, 아세틸화, 인산화등 다른 공유결합성 수식보다는 상대 적으로 안정되더라도, 히스톤 메 틸화로 유발되는 후생유전학적 변화가 불가역성이 아님을 알게 되었다.

• BMB Reports
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• 제48권7호
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• pp.401-406
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• 2015

Here we report that the H3K9 demethylase KDM3B represses transcription of the angiogenesis regulatory gene, ANGPT1. Negative regulation of ANGPT1 by KDM3B is independent of its Jumonji (JmjC) domain-mediated H3K9 demethylase activity. We demonstrate that KDM3B downregulates ANGPT1 via interaction with SMRT, and suggest that the repressor complex is formed at the promoter area of ANGPT1. Using MTT and wound healing assays, depletion of KDM3B was found to increase cell proliferation and cell motility, indicating that KDM3B has a role in angiogenesis. [BMB Reports 2015; 48(7): 401-406]

• Molecules and Cells
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• 제27권4호
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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.