• Journal of Plant Biotechnology
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• 제7권3호
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• pp.203-209
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• 2005

This study was conducted to improve tocopherol (vitamin E) composition in soybean (Glycine max) by introducing a gamma-tocopherol methyl transferase (${\gamma}$-TMT) gene via Agrobacterium tumefaciens-mediated transformation. Immature cotyledon explants were cocultivated with Agrobacterium tumefaciens. Putative transgenic embryos were selected from immature cotyledons on MS medium supplemented with 40 mg/L 2,4-D containing 100 mg/L kanamycin, 500 mg/L carbenicillin and 250 mg/L cefotaxime. Plantlets were developed from somatic embryos, and then transferred to soil. Nineteen regenerated plantlets obtained on the selection medium from 1,460 cotyledons. However, only 9 plantlets were confirmed as transformed plants. Integration of the transgene into the soybean genomic DNA was confirmed by PCR and Southern blot analysis. HPLC analysis showed that the content of ${\alpha}$-tocopherol in transgenic soybean seeds (AT-1) was approximately 4-fold higher than that of non-transgenic plants. Conclusively, we obtained the transgenic soybean having increased ${\alpha}$-tocopherol content by the overexpression of ${\gamma}$-TMT transgene.

• Environmental Analysis Health and Toxicology
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• 제13권3_4호
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• pp.55-61
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• 1998

Glutathione-S-transferases (GSTs) detoxify electrophilic xenobiotics and reactive metabolites. Recently benzene-fused heterocycles have been shown to increase the total amount of hepatic GSTs in rats. Primarily this study aimed to determine the induction of GSTs by benzoazoles (BAs) including benzoxazole (BX), 2-methylbenzoxazole (M-BX), 2,5-dimethyl benzoxazole (D-BX), benzothiazole (BT), aminobenzothiazole (A-BT) and 2-mercaptobenzothiazole (M-BT) in rats. Hepatic cytosol and poly(A)$^+$ mRNA were prepared from rats after oral administration of BX, BT, M-BX, D-BX, A-BT and M-BT for 5 consecutive days at doses of 1 mmol/kg. Western immunoblot and northern blot analysis were conducted with rabbit anti-GST Ya, Yb$_1$, Yb$_2$, Yc antibodies and cDNA probes containing = 500 bps in the specific coding regions of Ya, Yb$_1$, Yb$_2$, Yc$_1$, and Yc$_2$, respectively. All BAs increased the amount of enzymes and mRNA levels of GSTs. BT was the most effective inducer of GSTs among the compounds examined in this study. Although A-BT and M-BT, the derivatives of BT, induced GSTs, these chemicals had lesser effect on induction of GSTs than BT. The derivatives of BX also induced less GSTs than the parent compound and the addition of methyl group to the benzene ring of BX reduced the induction of GSTs. BAs had better inductive effects on the class $\alpha$(Ya, Yc) than class $\mu$ GSTs (Yb$_1$, Yb$_2$). BAs enhanced mRNA levels of GSTs in parallel with the protein levels. These results indicate that 1) most of BAs induced various isozymes of GSTs, 2) the induction of GSTs appears to be correlated with the chemical structure of the derivatives, and 3) the expression of GST by BAs is presumably under the transcriptional regulation.

• Archives of Pharmacal Research
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• 제19권5호
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• pp.374-380
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• 1996

Sprague-Dawley male rats (150 g) were chronically treated with 5 v/v % ethanol admixed with nutritionally complete liquid diet and fed ad libitum for 3 weeks. One half of each group was exposed to cold stress at 4 ^{\circ}C either for 24 h (for determination of mRNA by in situ hybridization) or for 48 h (for determination of enzyme activity). Chronic ethanol treatment (ethanol) did not affect tyrosine hydroxylase(TH) mRNA level in locus coeruleus(LC) of brain and adrenal medulla(AM) compared to controls. Cold stress showed strong increase of TH mRNA level in LC and AM compared to controls. Pretreated ethanol reduced the increased TH mRNA level by cold stress in LC and AM. Ethanol did not affect TH activity in LC and adenal glands(adrenals). Cold stress increased TH activity in LC but not in adrenals. Pretreated ethanol did not reduce the increased TH activity by cold stress in LC but this result was not shown in adrenals. Phenylethanolamine-N-methyltransferase(PNMT) activity in $C_{1}$$C_{2}$ and adrenals increased only in ethanol treated group. THese results suggest that ethanol does not affect TH mRNA level and activity in LC and adrenals, but increases PNMT activity in $C_{1}$$C_{2}$ and adrenals in normal rat. It is also suggested that pretreated ethanol reduces the magnitude of cold stress response, that is induction of TH mRNA in LC and AM, and does not reduce the protein activation of TH that is also cold stress response in LC.

• The Korean Journal of Physiology and Pharmacology
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• 제24권6호
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• pp.463-472
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• 2020

Direct reprogramming, also known as a trans-differentiation, is a technique to allow mature cells to be converted into other types of cells without inducing a pluripotent stage. It has been suggested as a major strategy to acquire the desired type of cells in cell-based therapies to repair damaged tissues. Studies related to switching the fate of cells through epigenetic modification have been progressing and they can bypass safety issues raised by the virus-based transfection methods. In this study, a protocol was established to directly convert fully differentiated fibroblasts into diverse mesenchymal-lineage cells, such as osteoblasts, adipocytes, chondrocytes, and ectodermal cells, including neurons, by means of DNA demethylation, immediately followed by culturing in various differentiating media. First, 24 h exposure of 5-azacytidine (5-aza-CN), a well-characterized DNA methyl transferase inhibitor, to NIH-3T3 murine fibroblast cells induced the expression of stem-cell markers, that is, increasing cell plasticity. Next, 5-aza-CN treated fibroblasts were cultured in osteogenic, adipogenic, chondrogenic, and neurogenic media with or without bone morphogenetic protein 2 for a designated period. Differentiation of each desired type of cell was verified by quantitative reverse transcriptase-polymerase chain reaction/western blot assays for appropriate marker expression and by various staining methods, such as alkaline phosphatase/alizarin red S/oil red O/alcian blue. These proposed procedures allowed easier acquisition of the desired cells without any transgenic modification, using direct reprogramming technology, and thus may help make it more available in the clinical fields of regenerative medicine.

• BMB Reports
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• 제52권5호
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• pp.342-347
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• 2019

Methylation is a primary epigenetic mechanism regulating gene expression. 5-aza-2'-deoxycytidine is an FDA-approved drug prescribed for treatment of cancer by inhibiting DNA-Methyl-Transferase 1 (DNMT1). Results of this study suggest that prolonged treatment with 5-aza-2'-deoxycytidine could induce centrosome abnormalities in cancer cells and that CEP131, a centrosome protein, is regulated by DNMT1. Interestingly, cancer cell growth was attenuated in vitro and in vivo by inhibiting the expression of Cep131. Finally, Cep131-deficient cells were more sensitive to treatment with DNMT1 inhibitors. These findings suggest that Cep131 is a potential novel anti-cancer target. Agents that can inhibit this protein may be useful alone or in combination with DNMT1 inhibitors to treat cancer.

• BMB Reports
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• 제53권12호
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• pp.634-639
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• 2020

In prostate cancer, the androgen receptor (AR) transcription factor is a major regulator of cell proliferation and metastasis. To identify new AR regulators, we focused on Mixed lineage leukemia 5 (MLL5), a histone-regulating enzyme, because significantly higher MLL5 expression was detected in prostate cancer tissues than in matching normal tissues. When we expressed shRNAs targeting MLL5 gene in prostate cancer cell line, the growth rate and AR activity were reduced compared to those in control cells, and migration ability of the knockdown cells was reduced significantly. To determine the molecular mechanisms of MLL5 on AR activity, we proved that AR physically interacted with MLL5 and other co-factors, including SET-1 and HCF-1, using an immunoprecipitation method. The chromatin immunoprecipitation analysis showed reduced binding of MLL5, co-factors, and AR enzymes to AR target gene promoters in MLL5 shRNA-expressing cells. Histone H3K4 methylation on the AR target gene promoters was reduced, and H3K9 methylation at the same site was increased in MLL5 knockdown cells. Finally, xenograft tumor formation revealed that reduction of MLL5 in prostate cancer cells retarded tumor growth. Our results thus demonstrate the important role of MLL5 as a new epigenetic regulator of AR in prostate cancer.

• Biomolecules & Therapeutics
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• 제29권1호
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• pp.73-82
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• 2021

Hsp90 is often overexpressed with activated form in cancer cells, and many key cellular proteins are dependent upon the Hsp90 machinery (these proteins are called "client protein"). Nowadays, more client proteins and more inhibitors of Hsp90 are being discovered. Chaetocin has been identified as an inhibitor of histone methyl transferase SUV39H1. Herein, we find that Chaetocin is an inhibitor of Hsp90 which binds to the C-terminal of Hsp90α. Chaetocin inhibited a variety of Hsp90 client proteins including AMl1-ETO and BCL-ABL, the mutant fusion-protein in the K562 and HL-60 cells. SUV39H1 mediates epigenetic events in the pathophysiology of hematopoietic disorders. We found that inhibition of Hsp90 by Chaetocin and 17-AAG had ability to induce degradation of SUV39H1 through proteasome pathway. In addition, SUV39H1 interacted with Hsp90 through co-chaperone HOP. These results suggest that SUV39H1 belongs to a client protein of Hsp90. Moreover, Chaetocin was able to induce cell differentiation in the two cells in the concentration range of Hsp90 inhibition. Altogether, our results demonstrate that SUV39H1 is a new client protein of Hsp90 degradated by Chaetocin as a novel C-terminal inhibitor of Hsp90. The study establishes a new relationship of Chaetocin and SUV39H1, and paves an avenue for exploring a new strategy to target SUV39H1 by inhibition of Hsp90 in leukemia.

• 한국발생생물학회지:발생과생식
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• 제6권2호
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• pp.117-122
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• 2002

포유동물에서 뇌와 부신에서 합성ㆍ분비되는 카테콜아민(Catecholamine, CA)계 신경전달물질인 dopamine(DA), norepinephrine(NE), epinephrine(E)은 체내 각종 생리현상의 조절에 필수적이며, 생식과 관련된 기능으로는 시상하부와 뇌하수체 사이의 GnRH-gonadotropin 호르몬 축의 활성을 조절함 외에도 번식과 연관된 여러 행동양식을 조절함이 잘 알려져 있다. 본 연구는 카테콜아민 생합성 효소인 tyrosine hydroxylase(TH), dopamine $\beta$ -hydroxylase(DBH), phenylethaolamine-N-methyl transferase(PNMT)의 유전자 발현에 영향을 미치는 sex steroid의 영향을 조사하였다. 성숙한 암컷 흰쥐의 난소를 제거(ovariectomy, OVX)하고 1주 경과 후 실험군과 대조군에 각각 17$\beta$-estradiol(E$_2$; 500$\mu\textrm{g}$/m1)이 들어 있는 silastic capsule과 sesame oil이 들어 있는 silastic capsule을 이식시키고 48시간 후에 희생시켰다. 채취된 조직에서 mRNA를 추출한 후 semi-quantitative reverse transcription-polymerase chain reaction(RT-PCR)을 시행하였다. 그 결과로 (i) TH의 발현 정도는 OVX＋Oil군에서는 시상하부 > Substantia nigra(SNc) > 부신 순으로, OVX＋E$_2$군에서는 SNc ) 시상하부 > 부신 순으로 나타났다. TH발현에 미치는 estradiol의 효과로 SNc와 부신에서는 유의한 증가를 보인데 비해 시상하부에서는 유의한 감소를 관찰하였다. (ⅱ) DBH 발현 정도는 OVX＋Oil군과 OVXi＋E$_2$군에서 모두 부신 > SNc > 시상하부 순으로 나타났다. DBH 발현에 미치는 estradiol의 효과로 SNc에서는 유의한 감소를, 부신에서는 유의한 증가를, 그리고 시상하부에서는 감소하였으나 통계적 유의성이 없었다. (ⅲ) PNMT의 발현의 경우 SNc와 시상하부에서는 이미 알려진 바와 같이 alternative splicing에 의해 110bp 차이의 크고 작은 두 형태의 cDNA(PNMT과 PNMTSs가 증폭되었으나 부신에서는 작은 cDNA(PNMTs)만이 관찰되었다. PNMT1의 발현은 SNc가 시상하부보다 다소 높은 경향이었으나 유의성이 없었고, PNMTs의 발현정도는 OVX＋Oil군과 OVX＋E$_2$군 모두에서 부신 > SNC >시상하부 순으로 나타났다. PNMTs 발현에 미치는 estradiol의 효과로 SNc에서는 유의한 감소를, 부신에서는 유의한 증가를, 그리고 시상하부에서는 통계적 유의성은 없으나 증가하는 경향을 보였다. 본 연구에서는 카테콜아민 생합성 효소들의 유전자 발현의 조절에 미치는 estrogen의 영향이 세포기원이 neural crest cell인 부신 수질은 물론 뇌의 상이한 지역간에서도 조직특이적임을 관찰하였다. 이러한 결과는 각 조직에서의 estrogen 수용체 유형의 차이, 작용 모드와 각 효소 유전자 발현 사이에 중요한 상관관계가 있음을 시사한다.

• BMB Reports
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• 제39권3호
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• pp.304-310
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• 2006

Transcription factor NF-E2-related factor 2 (Nrf2) regulates the induction of Phase II detoxifying enzymes and antioxidant enzymes in response to many cancer chemopreventive compounds. In this study, we investigated the role of receptor associated coactivator (RAC3) or steroid receptor coactivator-3 (SRC3) and other nuclear co-regulators including CBP/p300 (CREB-binding protein), CARM1 (Coactivator-associated arginine methyltransferase), PRMT1 (Protein arginine methyl-transferase 1), and p/CAF (p300/CBP-associated factor) in the transcriptional activation of a chimeric Gal4-Nrf2-Luciferase system containing the transactivation domain (TAD) of Nrf2 in HepG2 cells. The results indicated that RAC3 up-regulated the transactivation activity of Gal4-Nrf2-(1-370) in a dose-dependent manner. The enhancement of transactivation domain activity of Gal4-Nrf2-(1-370) by RAC3 was dampened in the presence of dominant negative mutants of RAC3. Next we studied the effects of other nuclear co-regulators including CBP/p300, CARM1, PRMT1 and p/CAF, and the results showed that they had different level of positive effects on this transactivation domain activity of Gal4-Nrf2-(1-370). But importantly, synergistic effects of these co-regulators in the presence of RAC3/SRC3 on the transactivation activity of Gal4-Nrf2-(1-370) were observed. In summary, our present study showed for the first time that the 160 RAC3/SRC3 is involved in the functional transactivation of TAD of Nrf2 and that the other nuclear co-regulators such as CBP/p300, CARM1, PRMT1 and p/CAF can also transcriptionally activate this TAD of Nrf2 and that they could further enhance the transactivation activity mediated by RAC3/SRC3.

• Journal of Preventive Medicine and Public Health
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• 제28권3호
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• pp.678-689
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• 1995

Chromium is one of the representative toxic substance by occupational exposure which damage the mucosa of respiratory tract including nasal septal perforation. The aim of this study is to evaluate the effect of chromium exposure on olfactory function and to obtain the fundamental information about chromium exposure. The authors performed olfactory function test, laboratory tests and questionnaire interview on the subject of three groups, that is, two exposed groups and one nonexposed group from May 1 to June 30, 1994. Exposed group 1 was 15 male workers without nasal septal perforation, exposed group 2 was 15 male workers with nasal septal perforation among 103 workers in 22 chromium plating factories, and nonexposed group was 15 male medical students. The gathered informations were histories of chromium exposure, habits of smoking and alcohol drinking, the concentrations of chromium in serum and urine, and asparate aminotransferase(AST), alanine aminotransferase(ALT), gamma-glutamyl transferase, etc. Olfactory function was checked by T and T olfectometer using phenyl ethyl alcohol(material A), methyl cyclopentenolone(material B), iso-valeric acid(material C), $\gamma$-undecalactone(material D), skatole(material E) and the results were expressed by detection threshold(DT) and recognition threshold(RT). There was a significant difference between exposed groups and nonexposed group in A, B, C, D, E substances by DT and in A, B, C, D substances by RT(P<0.01). The degree of olfactory dysfunction was highest in the exposed group 2 and lowest in the nonexposed group in all five substances by DT and it was same in A B, D substances RT and the difference of RT and DT. As summary, olfactory dysfunction by chromium exposure was recognized and the degree of olfactory dysfunction was higher in the exposed group with nasal septal perforation. Therefore, it would be helpful to apply olfactory function test for the early detection of olfactory dysfunction, and this test would be considered as the basic tool within workers' compensation system.