• 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.

• Journal of Life Science
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• v.30 no.8
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• pp.713-721
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• 2020

Adipogenesis as a model system is needed to understand the molecular mechanisms of human adipocyte biology and the pathogenesis of obesity, diabetes, and other metabolic syndromes. Many relevant studies have been conducted with a focus on gene expression regulation and intracellular signaling relating to Peroxisome proliferator-activated receptor gamma (PPARγ) and CCAAT/enhancer-binding protein alpha (C/EBPα), which are master adipogenic transcription factors. However, epigenome regulation of adipogenesis by epigenomic modifiers or histone mutations is not fully understood. Histone methylation is one of the major epigenetic modifications on gene expression in mammals, and histone H3 lysine methylation (H3Kme) in particular implicates cell differentiation during various tissue and organ development. During adipogenesis, cell type-specific enhancers are marked by histone H3K4me1 with the active enhancer mark H3K27ac. Mixed-lineage leukemia 4 (MLL4) is a major H3K4 mono-methyltransferase on the adipogenic enhancers of PPARγ and C/EBPα loci. Thus, MLL4 is an important epigenomic modifier for adipogenesis. The repressive mark H3K27me3 is mediated by the enzymatic subunit Enhancer zeste homolog 2 (EZH2) of the polycomb repressive complex 2. EZH2-mediated H3K27 tri-methylation on the Wnt gene increases adipogenesis because WNT signaling is a negative regulator of adipogenesis. This review summarizes current knowledge about the epigenomic regulation of adipogenesis by histone H3 lysine methylation which fundamentally regulates gene expression.

• Molecules and Cells
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• v.20 no.3
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• pp.423-428
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• 2005

Immediately after fertilization, a chromatin remodeling process in the oocyte cytoplasm extracts protamine molecules from the sperm-derived DNA and loads histones onto it. We examined how the histone H3-lysine 9 methylation system is established on the remodeled sperm chromatin in mice. We found that the paternal pronucleus was not stained for dimethylated H3-K9 (H3-$m_2K9$) during pronucleus development, while the maternal genome stained intensively. Such H3-$m_2K9$ asymmetry between the parental pronuclei was independent of $HP1{\beta}$ localization and, much like DNA methylation, was preserved to the two-cell stage when the nucleus appeared to be compartmentalized for H3-$m_2K9$. A conspicuous increase in H3-$m_2K9$ level was observed at the four-cell stage, and then the level was maintained without a visible change up to the blastocyst stage. The behavior of H3-$m_2K9$ was very similar, but not identical, to that of 5-methylcytosine during preimplantation development, suggesting that there is some connection between methylation of histone and of DNA in early mouse development.

• International Journal of Oral Biology
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• v.31 no.3
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• pp.81-86
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• 2006

SET (Suppressor of variegation, Enhancer of zeste, and the Trithorax) domain-containing proteins are known to have methyltransferase activity at lysine residues of histone proteins. In this study, we identified a novel SET domain-containing protein from mouse and named Kodo7. Indeed, Kodo7 has methyltransferase activity at K9 residue of the H3 protein as demonstrated by a histone methyl-transferse activity assay using GST-tagged Kodo7. Confocal microscopy showed that Kodo7 is co-localized with histones in the nucleus. Interestingly, ectopic expression of Kodo7 by transient transfection induced cell death and treatment of the transfectants with a caspase-3 inhibitor, Ac-DEVD-AFC decreased Kodo7-induced apoptosis. These results suggest that Kodo7 induces apoptotic cell death through increased methylation of histones leading to transcriptional repression.

• Journal of Applied Biological Chemistry
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• v.62 no.2
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• pp.157-165
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• 2019

Di- and tri-methylation of lysine 4 on histone H3 (H3K4me2 and H3K4me3, respectively) are epigenetic markers of active genes. Complex associated with Set1 (COMPASS) mediates these H3K4 methylations. The involvement of COMPASS activity in secondary metabolite (SM) biosynthesis was first demonstrated with an Aspergillus nidulans cclA knockout mutant. The cclA knockout induced the transcription of two cryptic SM biosynthetic gene clusters, leading to the production of the cognate SM. Monascus spp. are filamentous fungi that have been used for food fermentation in eastern Asia, and the pigment Monascus azaphione (MAz) is their main SM. Monascus highly produces MAz, implying that the cognate biosynthetic genes are highly active in transcription. In the present study, we examined how COMPASS activity modulates MAz biosynthesis by inactivating Monascus purpureus cclA (Mp-cclA) and swd1 (Mp-swd1). For both ${\Delta}Mp-cclA$ and ${\Delta}Mp-swd1$, a reduction in MAz production, accompanied by an abated cell growth, was observed. Suppression of MAz production was more effective in an agar culture than in the submerged liquid culture. The fidelity of the ${\Delta}Mp-swd1$ phenotypes was verified by restoring the WT-like phenotypes in a reversion recombinant mutant, namely, trpCp: Mp-swd1, that was generated from the ${\Delta}Mp-swd1$ mutant. Real-time quantitative Polymerase chain reaction analysis indicated that the transcription of MAz biosynthetic genes was repressed in the ${\Delta}Mp-swd1$ mutant. This study demonstrated that MAz biosynthesis is under the control of COMPASS activity and that the extent of this regulation is dependent on growth conditions.

• Journal of Microbiology and Biotechnology
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• v.27 no.1
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• pp.189-196
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• 2017

Kaposi's sarcoma-associated herpesvirus (KSHV) is associated with formation of Kaposi's sarcoma, multicentric Castleman's disease, and primary effusion lymphoma. Replication and transcription activator (RTA) genes are expressed upon reactivation of KSHV, which displays a biphasic life cycle consisting of latent and lytic replication phases. RTA protein expression results in KSHV genome amplification and successive viral lytic gene expression. Transcriptional activity of viral lytic genes is regulated through epigenetic modifications. In Raji cells latently infected with Epstein-Barr virus, various modifications, such as acetylation and methylation, have been identified at specific lysine residues in histone H4 during viral reactivation, supporting the theory that expression of specific lytic genes is controlled by histone modification processes. Data obtained from chromatin immunoprecipitation and quantitative real-time PCR analyses revealed alterations in the H4K8ac and H4K20me3 levels at lytic gene promoters during reactivation. Our results indicate that H4K20me3 is associated with the maintenance of latency, while H4K8ac contributes to KSHV reactivation in infected TREx BCBL-1 RTA cells.

• Animal cells and systems
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• v.16 no.4
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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.

• Molecules and Cells
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• v.38 no.6
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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.

• Journal of Life Science
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• v.21 no.4
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• pp.616-620
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• 2011

Lysine residues of histone H3 and H4 are covalently modified in the chromatin of eukaryotic cells. Lysine 27 in histone H3 was acetylated (H3K27ac) or methylated at three levels; mono-, di-, and trimethylation (H3K27me1, H3K27me2, and H3K27me3). These modifications at H3K27 were related with gene transcription and/or chromatin structure in distinct patterns. Generally, H3K27ac and H3K27me1 were enriched in active chromatin, such as the locus control region or transcriptionally active genes, while transcriptionally inactive genes were highly marked by H3K27me2 and H3K27me3. These modifications appear to have been catalyzed by distinct histone-modifying enzymes. Recent studies suggest that the four kinds of modifications at H3K27 have inter-correlation in gene transcription or chromatin structure formation.

• BMB Reports
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• v.50 no.4
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• pp.162-163
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• 2017

RNA polymerase II-interacting the Set2 methyltransferase co-transcriptionally methylates histone H3 at lysine 36 within the body of genes. This modification facilitates histone deacetylation by Rpd3S HDAC in 3' transcribed regions to suppress cryptic initiation and slow elongation. Although this pathway is important for global deacetylation, no strong effects have been seen on genome-wide transcription under optimized laboratory conditions. In contrast, this pathway slows the kinetics of mRNA induction when target genes are induced upon environmental changes. Interestingly, a majority of Set2-repressed genes are overlapped by a lncRNA transcription that targets H3K36 methylation and deacetylation by Rpd3S HDAC to mRNA promoters. Furthermore, this pathway delays the induction of many cryptic transcripts upon environmental changes. Therefore, the Set2-Rpd3S HDAC pathway functions to fine-tune expression dynamics of mRNAs and ncRNAs.