DNA in the eukaryotic nucleus is packaged into highly organized chromatin. The basic structural unit of chromatin is the nucleosome, which consists of approximately 146 base pairs of DNA wrapped around a histone octamer core containing two molecules each of core histones H2A, H2B, H3, and H4. Histone covalent modification at the protruding N-terminal region from the nucleosomal core can change the chromatin conformation in order to regulate gene expression. A viral H4 was found in the genome of Cotesia plutellae bracovirus (CpBV). The obligate host of the virus is an endoparasitoid wasp, C. plutellae, which parasitizes the diamondback moth, Plutella xylostella, and interrupts host development and immune reactions. CpBV-H4 has been regarded as an immunosuppressive gene. Its extended N-terminal region contains nine lysine residues which are the target for modification. Previous report showed that CpBV-H4 inhibited hemocyte-spreading after transient expression. Here, transient expression of truncated CpBV-H4 (without N-terminal region) did not show high inhibitory effects on hemocyte-spreading. Moreover, the truncated CpBV-H4 induced acetylation of nucleus histone H4. Host H4 was found to be decreased in transcription after parasitization compared to nonparasitized larvae. Atransient expression of CpBV-H4 significantly inhibited host H4 transcription, suggesting a role of CpBV-H4 in controlling gene expression. Point mutagenesis study showed that two lysines (K6 and K16) of CpBV-H4 were found to have high inhibitory effects on hemocyte spreading. These results indicate the importance of CpBV-H4 and its N-terminal region to control gene expression and suppress host immunity.

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.

In this study, we produced the recombinant lunasin peptide using E. coli and P. pastoris, and evaluated biological activity of the recombinant lunasin peptide. Lunasin peptide was produced from E. coli transfected with pPGEX-lunasin expression vector and P. pastoris GS115 transfected with pPIC-lunasin expression vector. These recombinant lunasin peptides were similar to the synthetic lunasin peptide in the identification by LC-ESI-MS. In addition, the recombinant lunasin peptide from E. coli and P. pastoris was bound in the chromatin, and inhibited histone acetylation and the activity of histone acetyltransferase. These findings suggest that the production of the lunasin peptide using E. coli and P. pastoris will be useful for industrial utilization of lunasin peptide.

In this study, we produced the recombinant lunasin peptide using E. coli and P. pastoris, and evaluated biological activity of the recombinant lunasin peptide. Lunasin peptide was produced from E. coli transfected with pPGEX-lunasin expression vector and P. pastoris GS115 transfected with pPIC-lunasin expression vector. These recombinant lunasin peptides were similar to the synthetic lunasin peptide in the identification by LC-ESI-MS. In addition, the recombinant lunasin peptide from E. coli and P. pastoris was bound in the chromatin, and inhibited histone acetylation and the activity of histone acetyltransferase. These findings suggest that the production of the lunasin peptide using E. coli and P. pastoris will be useful for industrial utilization of lunasin peptide.

Flowering time is a important agronomic trait for grain production in rice. So the control of flowering time is a critical step. In Arabidopsis, expression of certain key flowering gene such as FLOWERING LOCUS C (FLC) is known to be epigenetically regulated by chromatin modification through Enhancer of Zeste[E(z)], a histone methyltransferase, that core component of repressive complex, polycomb repressive complex2(PRC2). However, the chromatin mechanism involved in the regulation of rice flowering genes is presently not well known. Here we show that predict coding region of a intronic LncRNA[termed rice COLDAIR(OsCOLDAIR)], which is expected to associate with a component of PRC2, is predicted at rice FLC gene. And additionally we suggest interaction of histone methyltransferase and E3 SUMO ligase that indicate possibility of interaction with rice E(z) gene and rice E3 SUMO ligase. Our study contribute to control of rice flowering time by observing two factor that can regulate expression of related of rice FLC gene.

염색체분리를 위해서는 미세소관과 동원체의 부착에 관여하는 단백질들이 정확한 시기와 위치에서 조절이 되어야 한다. 이 과정은 주로 Chromosomal passenger complex(CPC)에 의해 조절되게 되는데, 체세포 분열에서는 Histone H3 Thr 3 자리의 인산화가 CPC를 동원체로 불러오게 함으로써 염색체 분리의 과정이 가능하게 해준다고 알려져 있다. 이러한 기작은 미세소관이 동원체에 비정상적으로 부착되었을 시에 발생하는 오류를 바로 잡을 수 있게 해준다. 그러나 이에 대한 과정은 아직까지 감수분열에서 알려진 바가 없다. 먼저, 감수분열에서의 Histone H3 Thr 3의 인산화 활성을 알아보았다. Histone H3 Thr 3의 인산화는 제 1 감수분열 전기에서 중기까지 염색체 전부에서 점차적으로 증가하는 양상을 보였다. 하지만 제 1 감수분열 후기로 접어들면서 염색체의 팔에서 발현되었던 인산화는 줄어들고, 동원체에서만 발현되는 것을 확인할 수 있었다. Histone H3 Thr 3 인산화 기능을 알아보기 위해서, 이를 인산화 하는 Haspin 카이네즈 저해제를 난자에 처리하였다. 저해제가 처리된 난자에서는 Histone H3 Thr 3의 인산화가 사라지면서 세포주기가 중기에서 멈췄고, CPC가 염색체에서 확산되면서 염색체가 적도판에서 비정상적으로 정렬되었다. 따라서 본 연구의 결과를 토대로 감수분열 동안 Histone H3 Thr 3의 인산화 활성이 염색체의 분리가 적절한 시기와 위치에서 이루어지게 하는 중요한 역할을 한다고 할 수 있다.

In the era of systems biology, plant biologists approach any given phenomena, that they have great interests, from different perspectives. Among them, both epigenomic and epigenetic studies give us new insights into plant immune response as well as development. In plants, recognition of invading pathogenic microorganisms by pattern recognition receptor and race-specific resistance protein activates diverse cellular responses to defend plants against pathogen infection. One of well-known immune responses is the transcriptional reprogramming occurring when pathogen infects plant. Chromatin remodeling caused by change of histone marks and replacement of histone variants affects gene expression that is important for immunity. We are focused on unveiling epigenomic and epigenetic regulatory mechanisms of plant immunity. To address these questions, we have collected knockout mutant plants whose genes might be related to histone modifications, and identified several enhanced-immune (eni) mutants and immune-defective (imd) mutants. Here, we will introduce one of mutants showing enhanced disease resistance (EDR) in response to the infection of Pseudomonas. Thus we named it eni2. Both the growth of virulent bacteria, not avirulent derivatives of Pseudomonas syringae, and symptom development were effectively inhibited in the eni2 mutants, compared with those seen in wild type. Unlike to well-known EDR-type mutants, the levels of salicylic acid in the eni2 mutant plants were not different from those in wild type. Thus we suggests a few plausible scenarios about role of ENI2 in plant immune response. To examine these possibilities, we are monitoring transcriptional reprogramming occurring in eni2 mutants through RNA-seq analysis. On the other hand, we have recently initiated the study of tomato small RNAome in order to discover immune-related small RNAs from leaves infected with Pseudomonas syringae via next-generation sequencing technology. Here we present the recent progress in this study.

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 c

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.