• BMB Reports
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• 제51권5호
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• pp.211-218
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• 2018

Chromatin is an intelligent building block that can express either external or internal needs through structural changes. To date, three methods to change chromatin structure and regulate gene expression have been well-documented: histone modification, histone exchange, and ATP-dependent chromatin remodeling. Recently, a growing body of literature has suggested that histone tail cleavage is related to various cellular processes including stem cell differentiation, osteoclast differentiation, granulocyte differentiation, mammary gland differentiation, viral infection, aging, and yeast sporulation. Although the underlying mechanisms suggesting how histone cleavage affects gene expression in view of chromatin structure are only beginning to be understood, it is clear that this process is a novel transcriptional epigenetic mechanism involving chromatin dynamics. In this review, we describe the functional properties of the known histone tail cleavage with its proteolytic enzymes, discuss how histone cleavage impacts gene expression, and present future directions for this area of study.

• Journal of Microbiology and Biotechnology
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• 제5권1호
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• pp.26-30
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• 1995

The cytoplasmic endo-$\beta$-l, 4-glucanase (endoglucanase) was purified from cell extracts of Escherichia coli (pBS1) transformant carrying the Bacillus subtilis endo-$\beta$-l, 4-glucanase gene after full growth, and its molecular weight was found to be 52 kilodaltons (kDa). The endo-$\beta$-l, 4-glucanase isolated from the periplasmic space was smaller than 52-kDa cytoplasmic enzyme. The 52-kDa endoglucanase was found to be cleaved in the periplasm and finally converted to 34.5-kDa protein. Small amounts of both 52-kDa and 34.5-kDa proteins were secreted into the culture broth. The cleavage took place in the C-terminal portion of the enzyme. The N-terminal amino acid residues of both 52-kDa and 34.5-kDa enzymes were determined to be the same, Ala, the 30th residue of the primary translation product. Cleavage of the C-terminal portion showed to have no significant effect on the basic enzyme properties.

• BMB Reports
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• 제34권2호
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• pp.150-155
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• 2001

The mosquito-larvicidal Cry4B protein from Bacillus thuringiensis subsp. israelensds was expressed in Escherichia coli. Upon activation by trypsin, the 130-kDa protoxin was processed into the 65-kDa active toxin containing two polypeptide fragments of ca. 47 and ca. 20 kDa. These two polypeptides are products of internal cleavages on the exposed loop connecting helices 5 and 6 in the seven-helical bundle domain. PCR-based mutagenesis was employed to introduce an additional cleavage site into the loop connecting helices 3 and 4. A series of amino acid changes were introduced into the targeted loop, resulting in seven mutant protoxins. Upon digestion with trypsin, a group of mutants with arginine introduced into the loop (EPRNQ, EPNRNQ, EPRNP, ESRNP and SSRNP) produced polypeptide products similar to those of the wild type (EPNNQ). When the loop, SSRNP, was expanded by an insertion of either asparagine (NSSRNP) or valine (VSSRNP), an additional cleavage was detected with proteolytic products of 47,12 and 6 kDa. This cleavage was confirmed to be at the introduced arginine residue by N-terminal sequencing. The mosquito larvicidal assay against Aedes aegypti demonstrated a relatively unchanged toxicity for the mutants without cleavage and reduced toxicity for those with an additional cleavage.

• Journal of Microbiology and Biotechnology
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• 제14권2호
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• pp.430-434
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• 2004

Three extracellular protease-deficient Bacillus subtilis strains were transformed with the plasmid pCK98 containing the endo-$\beta$-1,4-glucanase (Eng) gene of B. subtilis BSE616. The three transformants, B. subtilis DB104 (pCK98), WB600 (pCK98) and WB700 (pCK98), produced the same high level of enzyme activity and showed similar patterns of cell growth and enzyme production. When B. subtilis DB 104 (pCK98), a two-extracellular protease deficient strain, was cultured for 22 h, almost all the secreted enzyme was found to be in the completely cleaved form by both activity staining and Western blotting studies. B. subtilis WB600 (pCK98), a six-extracellular protease-deficient strain, produced a partially cleaved form in addition to the intact form of the enzyme, although the degree of internal cleavage of the enzyme was greatly reduced. With B. subtilis WB700 (pCK98), a seven-extracellular protease-deficient strain, almost all the enzyme was produced as the intact uncleaved form. This study illustrates that a role of the V pr protease is to degrade foreign proteins produced in B. subtilis and WB700 is a suitable expression system for producing the intact form of the Eng and other foreign proteins that may lose at least part of their efficacy due to internal proteolytic cleavage.

• 생명과학회지
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• 제24권12호
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• pp.1378-1382
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• 2014

Phospholipase D (PLD)는 세포막을 구성하는 주요지질인 인지질을 분해하여, 이차신호전달물질인 phosphatidic acid (PA)를 생성함으로써 세포의 성장 및 증식, 생존신호전달등 세포내 다양한 생리현상을 조절하는 중요한 신호전달 핵심단백질로 대두되고 있다. PLD의 비정상적인 발현과 활성은 다양한 암을 비롯한 여러 질환에서 나타난다. PLD에 의해 생성된 PA는 세포사멸 유전자의 발현을 감소시켜서 세포사멸에 대한 내성을 나타내고 있다.최근에, 세포사멸과정에서 PLD 단백질의 turnover dynamics에 관한 분자수준에서의 연구가 규명되었다. PLD는, 세포사멸시 활성화되는 단백질 분해효소인 caspases의 새로운 기질로 작용하여 세포사멸을 차별적으로 조절을 한다. Caspase에 의한 PLD동위효소의 차별적인 분해양상이 PLD의 효소활성과 세포사멸억제 기능을 조절한다. 그래서 PLD는 암치료의 표적분자로서의 가능성이 제시된다. 본 리뷰논문에서, 세포사멸조절 PLD의 기능적 역할에 대해 서술하고자 한다.

• 동의생리병리학회지
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• 제18권5호
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• pp.1374-1381
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• 2004

The water extract of Dohongsamul-tang(DHSMT)has been traditionally used for treatment of ischemic heart in oriental medicine. However, little is known about the mechanism by which the water extract of DHSMT rescues cells from these damages. Therefore, this study was designed to evaluate the protective effects of DHSMT on zinc-mediated cytotoxicity in H9c2 cardiomyoblast cells. This study demonstrates that treatment of H9c2 cells with zinc caused a decrease in cell viability in a dose dependent manner and a chromatin condensation. Zinc induced the cleavage of poly(ADP-ribose) polymerase (PARP). In addition, zinc induced the decrease of Bcl-2, as well as increase of Bak expression and mitochondrial dysfunction. Zinc-induced H9c2 cell death was remarkably prevented by the pretreatment of DHSMT with consistent suppression of the cleavage of poly(ADP-ribose) polymerase (PARP), mitochondrial dysfunction and the expression of Bak and Bcl-2. Taken together, the results suggest that zinc induced severe cell death in H9c2 cardiomyoblast cells via intracellular GSH(reduced glutathione) depletion and the protective effects of DHSMT against oxidative injuries may be achieved through modulation of mitochondrial dysfunction and scavenging of ROS(reactive oxygen species).

• 대한기계학회논문집
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• 제7권2호
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• pp.123-129
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• 1983

The effect of the micro-internal stress which is induced in the ferrite grain by plastic constraint, on fracture behavior was investigated. The specimen used has combined microstructure with matrix of ferrite encapsulated by second phase of martensite. The micro-internal stress in the ferrite grain was estimated using a simple mechanical model, and its effect on micro and macro fracture behaviors was discussed. The results obtained are summarized as follows; The micro-internal stress promotes the formation of cleavage cracks in the ferrite during deformation. Consequently, it was concluded that the internal stress is one of the significant factors which cause the fracture ductility to decrease.

• Tuberculosis and Respiratory Diseases
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• 제71권4호
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• pp.259-265
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• 2011

Background: Epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors, gefitinib and erlotinib, are effective therapies for non-small cell lung cancer (NSCLC) patients whose tumors harbor somatic mutations in EGFR. The mutations are, however, only found in about 30% of Asian NSCLC patients and all patients ultimately develop resistance to these agents. Ionizing radiation has been shown to induce autophosphorylation of EGFR and activate its downstream signaling pathways. In the present study, we have tested whether the effect of gefitinib treatment can be enhanced after ionizing radiation. Methods: We compared the PC-9 and A549 cell line with its radiation-resistant derivatives after gefitinib treatment with cell proliferation and apoptosis assay. We also analyzed the effect of gefitinib after ionizing radiation in PC-9, A549, and NCI-H460 cells. Cell proliferation was determined by MTT assay and induction of apoptosis was evaluated by flow cytometry. Caspase 3 activation and PARP cleavage were evaluated by western blot analysis. Results: PC-9 cells having mutated EGFR and their radiation-resistant cells showed no significant difference in cell viability. However, radiation-resistant A549 cells were more sensitive to gefitinib than were their parental cells. This was attributable to an increased induction of apoptosis. Gefitinib-induced apoptosis increased significantly after radiation in cells with wild type EGFR including A549 and NCI-H460, but not in PC-9 cells with mutated EGFR. Caspase 3 activation and PARP cleavage accompanied these findings. Conclusion: The data suggest that gefitinib-induced apoptosis could increase after radiation in cells with wild type EGFR, but not in cells with mutated EGFR.

• Molecules and Cells
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• 제42권5호
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• pp.418-425
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• 2019

Multicistronic elements, such as the internal ribosome entry site (IRES) and 2A-like cleavage sequence, serve crucial roles in the eukaryotic ectopic expression of exogenous genes. For utilization of multicistronic elements, the cleavage efficiency and order of elements in multicistronic vectors have been investigated; however, the dynamics of multicistronic element-mediated expression remains unclear. Here, we investigated the dynamics of encephalomyocarditis virus (EMCV) IRES- and porcine teschovirus-1 2A (p2A)-mediated expression. By utilizing real-time fluorescent imaging at a minute-level resolution, we monitored the expression of fluorescent reporters bridged by either EMCV IRES or p2A in two independent cultured cell lines, HEK293 and Neuro2a. We observed significant correlations for the two fluorescent reporters in both multicistronic elements, with a higher correlation coefficient for p2A in HEK293 but similar coefficients for IRES-mediated expression and p2A-mediated expression in Neuro2a. We further analyzed the causal relationship of multicistronic elements by convergent cross mapping (CCM). CCM revealed that in all four conditions examined, the expression of the preceding gene causally affected the dynamics of the subsequent gene. As with the cross correlation, the predictive skill of p2A was higher than that of IRES in HEK293, while the predictive skills of the two multicistronic elements were indistinguishable in Neuro2a. To summarize, we report a significant temporal correlation in both EMCV IRES- and p2A-mediated expression based on the simple bicistronic vector and real-time fluorescent monitoring. The current system also provides a valuable platform to examine the dynamic aspects of expression mediated by diverse multicistronic elements under various physiological conditions.

• 대한한방종양학회지
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• 제9권1호
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• pp.15-37
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• 2003

Objective: We are aimed to identify anti-tumor effects of Curcuma longa L. on the stomach cancer cells through molecular biologic methods. Material & Methods: We used AGS as human stomach cancer cells obtained from American Type Culture Collection. The boiled extract of Curcuma longa L. $5{\mu}l$ (Sample I), $10{\mu}l$ (Sample II) was treated to cultural media(ml) for 0, 6, 12, 24, 48 hours. We measured the killing effect on stomach cancer cells through Trypan blue exclusion test and the suppressive effect on viability of stomach cancer cells via MTT assay. For identification of its anticancer mechanism, the revelation of Bcl-2, Bcl-XL, and Bax which are genes related to apoptosis using the quantitative RT-PCR, change of mitochondria membrane permeability and membrane potential via flow cytometry, the cycle of cell mitosis, caspase cleavage and annexin V staining were examined. Results: 1. showed significant killing effect on stomach cancer cell than the control group with a time(6 hours later) and density dependent manner, which was statistical significance. 2. Extract of Curcuma longa L. showed suppressive effect on viability of stomach cancer cells that each test groups had more suppressive effects on viability of stomach cancer cells than the control group with a time(6 hours later), which was statistical significance.(p<0.05) 3. In the test about the revelation of genes related to apoptosis, the revelation of Bcl-2 and Bcl-XL decreased with a density manner which was statistical significance. but the revelation of Bax was not changed with statistical significance. 4. Extract of Curcuma longa L. caused apoptosis by decreasing the absorbance of mitochondria with statistical significance, and also induced apoptosis by decreasing the membrane potential of mitochondria. 5. Extract of Curcuma longa L. destructed the cell cycle of cell mitosos. 6. Cell apoptosis was induced by extract of Curcuma longa L. certificated by method of caspase cleavage and annexin V staining. Conclusion: This experiment showed that Curcuma longa L. has anti-tumor effect with statistical significance. This is in vitro experiment and basic experiment on Curcuma longa L.. We hope more progressive research on Curcuma longa L. will go on and its anti-tumor effects will be more practically identified.