• 대한수의학회지
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• 제7권2호
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• pp.13-18
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• 1967

1. Within experimental chromatin, the total protein: DNA ratio did not vary in the same organs of control and irradiated rats. However, the amount of RNA and total protein associated with the DNA varied considerably among the different types of chromatin. In particular, the content of chromatin was the control tissue. RNA and total protein ratio of chromatins from brtain, liver, testis and spleen declined with experimental I organs. 2. There was the same quantitative relationship between the amount of RNA and the amount of histone-protein associated with DNA in chromatin. 3. RNA: DNA ratio of chromatin showed 1.5-2 times increas in the irradiated organs except brain. However, RNA: DNA ratio was decreased in chromatin by irradiation. 4. Histone-protein:residual protein ratio was greatly varied among the organs. However, the effect was not found by irradiation. 5. Priming activity of chromatin showed a higher value in testis and the activity was greater in organs with higher metabolic activity: 6. Inhibition of Actinomycin D is observable in chromatin from testis, liver, spleen and brain declined without relationship between irradiated and non-irradiated conditions. Ammonium sulfate showed increased priming activity by the electrostatic dissociation of DNA and histone in chromatin on the stimulation depending on property of chromatins. 7. It is suggested that the results support a proposal that testis and spleen of highly sensitive to irradiation should an increase in the priming activity whereas brain and liver of lower sensitivity decreased in the activity.

• Archives of Pharmacal Research
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• 제27권6호
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• pp.640-645
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• 2004

Histone deacetylase inhibitors are new class of chemotherapeutic drugs able to induce tumor cell apoptosis and／or cell cycle arrest. Trichostatin A, an antifungal antibiotic, and HC-toxin are potent and specific inhibitors of histone deacetylase activity. In this study, we have examined the antiproliferative activities of trichostatin A and HC-toxin in estrogen receptor positive human breast cancer, T47D cells. Both trichostatin A and HC-toxin showed potent antiprolifer-ative efficacy and cell cycle arrest at $G_2/M$ in T47D human breast cancer cells in a dose-dependent manner. Trichostatin A caused potent apoptosis of T47D human breast cancer cells and trichostatin A-induced apoptosis might be involved in an increase of caspase-3／7 activity. HC-toxin evoked apoptosis of T47D cells and HC-toxin induced apoptosis might not be medi-ated through direct increase in caspase-3/7 activity. We have identified potent activities of anti-proliferation, apoptosis, and cell cycle arrest of trichostatin A and HC-toxin in estrogen receptor positive human breast cancer cell line T47D.

• Molecules and Cells
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• 제41권7호
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• pp.665-675
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• 2018

Rice is a facultative short-day (SD) plant in which flowering is induced under SD conditions or by other environmental factors and internal genetic programs. Overexpression of Histone Deacetylase 701 (HDT701) accelerates flowering in hybrid rice. In this study, mutants defective in HDT701 flowered late under both SD and long-day conditions. Expression levels of florigens Heading date 3a (Hd3a) and Rice Flowering Locus T1 (RFT1), and their immediate upstream floral activator Early heading date 1 (Ehd1), were significantly decreased in the hdt701 mutants, indicating that HDT701 functions upstream of Ehd1 in controlling flowering time. Transcript levels of OsINDETERMINATE SPIKELET 1 (OsIDS1), an upstream repressor of Ehd1, were significantly increased in the mutants while those of OsGI and Hd1 were reduced. Chromatin-immunoprecipitation assays revealed that HDT701 directly binds to the promoter region of OsIDS1. These results suggest that HDT701 induces flowering by suppressing OsIDS1.

• Archives of Pharmacal Research
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• 제8권3호
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• pp.149-157
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• 1985

The HCL hydrolyzate of the non-histone protein fractionated from the rat liver nuclei which have been incubated inthe presence of S-adenosyl-L-[methyl-$^{14}C$ ]-methionine shows at least four unidentified radioactive peaks on a basic amino acid analysis chromatogram. One of these unknown compounds (designated as compound 3) is also formed by the rat liver homogenated with the exogenous addition of an appropriate protein substrate. Since boiled rat liver homogenate or fresh homogenate in the absence of an exogenous protein substrate failed to form compound 3, its formation can be considered to be enzyme-catalyzed. The enzyme which yields compound 3 shows a preference of protein substrate in the order of reductively methylated hemoglobin > native > histone type II-A. The rat enzyme is nuclear in location associated with chromatin, and exhibits the highest activity in the liver among various rat organs. A compound 3-forming enzyme is also present in Neurospora crassa, since endogenous formation of the compound 3 can be demonstrated with the crude extract of this mold. The chemical identity of compound 3 is not yet known. However, it resisted to the following treatments; 6 N HCL and 0.1 N Na NaOH hydrolysis at $110^{\circ}C$, OR L-amino acid oxidase.

• Molecules and Cells
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• 제45권9호
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• pp.622-630
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• 2022

Colorectal cancer (CRC) has a high mortality rate among cancers worldwide. To reduce this mortality rate, chemotherapy (5-fluorouracil, oxaliplatin, and irinotecan) or targeted therapy (bevacizumab, cetuximab, and panitumumab) has been used to treat CRC. However, due to various side effects and poor responses to CRC treatment, novel therapeutic targets for drug development are needed. In this study, we identified the overexpression of EHMT1 in CRC using RNA sequencing (RNA-seq) data derived from TCGA, and we observed that knocking down EHMT1 expression suppressed cell growth by inducing cell apoptosis in CRC cell lines. In Gene Ontology (GO) term analysis using RNA-seq data, apoptosis-related terms were enriched after EHMT1 knockdown. Moreover, we identified the CHOP gene as a direct target of EHMT1 using a ChIP (chromatin immunoprecipitation) assay with an anti-histone 3 lysine 9 dimethylation (H3K9me2) antibody. Finally, after cotransfection with siEHMT1 and siCHOP, we again confirmed that CHOP-mediated cell apoptosis was induced by EHMT1 knockdown. Our findings reveal that EHMT1 plays a key role in regulating CRC cell apoptosis, suggesting that EHMT1 may be a therapeutic target for the development of cancer inhibitors.

• 생명과학회지
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• 제15권5호
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• pp.726-733
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• 2005

Histone deacetylase (HDAC) 억제제가 새로운 항암치료제 후보물질로서 유용성이 높은 것으로 평가되지만, 아직까지 인체폐암세포에 관한 연구는 상대적으로 미미한 실정이다. 따라서 본 연구에서는 폐암세포에 미치는 HDAC 억제제의 항암작용 기전을 조사하기 위하여 A549 인체폐암세포주를 대상으로 암세포의 증식에 미치는 대표적인 HDAC 억제제인 tichostatin A (TSA)에 의한 영향을 세포주기 조절관련인자 중심으로 조사하였다. TSA의 처리에 의하여 A549 폐암세포의 증식은 처리 농도 의존적으로 억제되었으며, 심한 형태적 변형을 동반하였다. 저농도 처리군에서는 TSA 농도가 증가할수록 세포주기 G1기의 빈도가 증가하였으나, 고농도 처리군에서는 G2/M기에 속하는 세포의 빈도가 증가되었다. 또한 apoptosis 유발의 간접적인 지표가 되는 sub-G1기에 속하는 세포의 빈도 역시 TSA 처리 농도 의존적으로 매우 증가되었다. 이러한 TSA의 A549 폐암세포 증식억제 효과는 cyclins 및 CdkS의 발현 억제, 종양억제유전자인 p53 및 Cdks 억제제인 p21과 p27의 발현 증가와도 연관성이 있었다. TSA의 항암 기전을 규명하기 위해서는 더 많은 연구가 부가적으로 필요하겠지만, 본 연구의 결과들에 의하면 TSA는 강력한 인체폐암세포의 증식 억제 및 항암작용이 있음을 시사하여 준다고 할 수 있다.

• 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.

• Asian Pacific Journal of Cancer Prevention
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• 제14권12호
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• pp.7529-7536
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• 2013

Background and Aims: MicroRNA-21 (miR-21) is reported to be overexpressed and to contribute to proliferation, apoptosis and gemcitabine resistance in pancreatic ductal adenocarcinomas (PDACs). The aims of this study were to explore regulation of miR-21 expression by epigenetic change and its impact on chemoresistance and malignant properties of of pancreatic cancer. Materials and methods: We retrospectively collected 41 cases of advanced pancreatic cancer patients who were sensitive or resistant to gemcitabine and assessed levels of serum circulating miR-21 for correlation with cytotoxic activity. Histone acetylation in the miR-21 promoter was also studied in gemcitabine-sensitive and gemcitabine-resistant PDAC cells. Gemcitabine-resistant HPAC and PANC-1 cells were transfected with pre-miR-21 precursors (pre-miR-21) and antisense oligonucleotides (anti-miR-21), and were treated with TSA. Finally, invasion and metastasis assays were performed and alteration in mir-21, PTEN, AKT and pAKT level was evaluated in these cells. Results: Serum miR-21 levels were increased in gemcitabine-resistant PDAC patients compared with gemcitabine-sensitive subjects. The miR-21 levels were increased in 6 PDAC cells treated with gemcitabine significantly, associated with 50% inhibitory concentrations ($IC_{50}s$). Histone acetylation levels at miR-21 promoter were increased in PDAC cells after treatment with gemcitabine. Enhanced invasion and metastasis, increased miR-21 expression, decreased PTEN, elevated pAKT level were demonstrated in gemcitabine-resistant HPAC and PANC-1 cells. Pre-miR-21 transfection or TSA treatment further increased invasion and metastasis ability, decreased PTEN, and elevated pAKT levels in these two lines. In contrast, anti-miR-21 transfection could reverse invasion and metastasis, and PTEN and pAKT expressions induced by gemcitabine. Conclusions: MiR-21 upregulation induced by histone acetylation in the promoter zone is associated with chemoresistance to gemcitabine and enhanced malignant potential in pancreatic cancer cells.

• 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.

• 한국미생물생명공학회:학술대회논문집
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• 한국미생물생명공학회 2003년도 2003 Annual Meeting, BioExhibition and International Symposium
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• pp.154-154
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• 2003