• Molecules and Cells
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• 제27권1호
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• pp.15-19
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• 2009

Notch signaling is controlled at multiple levels. In particular, stabilized Notch receptor activation directly affects the transcriptional activations of Notch target genes. Although some progress has been made in terms of defining the regulatory mechanism that alters Notch stability, it has not been determined whether Notch1/NICD stability is regulated by $GSK-3{\alpha}$. Here, we show that Notch1/NICD levels are significantly regulated by $GSK-3{\beta}$ and by $GSK-3{\alpha}$. Treatment with LiCl (a specific GSK-3 inhibitor) or the overexpression of the kinase-inactive forms of $GSK-3{\alpha}/{\beta}$ significantly increased Notch1/NICD levels. Endogenous NICD levels were also increased by either $GSK-3{\alpha}/{\beta}$- or $GSK-3{\alpha}$-specific siRNA. Furthermore, it was found that $GSK-3{\alpha}$ binds to Notch1. Deletion analysis showed that at least three Thr residues in Notch1 (Thr-1851, 2123, and 2125) are critical for its response to LiCl, which increased not only the transcriptional activity of endogenous NICD but also Hes1 mRNA levels. Taken together, our results indicate that $GSK-3{\alpha}$ is a negative regulator of Notch1/NICD.

• Molecular & Cellular Toxicology
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• 제4권2호
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• pp.164-169
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• 2008

Methylmercury (MeHg) is known to have devastating effects on the mammalian nervous system. In order to characterize the mechanism of MeHg-induced neurotoxicity, we investigated the analysis of transcriptional profiles on human 8k cDNA microarray by treatment of $1.4{\mu}M$ MeHg at 3, 12, 24 and 48h in human neuroblastoma SH-SY5Y cell line. Some of the identified genes by MeHg treatment were significant at early time points (3h), while that of others was at late time points (48h). The early response genes that may represent those involved directly in the MeHg response included pantothenate kinase 3, a kinase (PRKA) anchor protein (yotiao) 9, neurotrophic tyrosine kinase, receptor, type 2 gene, associated with NMDA receptor activity regulation or perturbations of central nervous system homeostasis. Also, when SH-SY5Y cells were subjected to a longer exposure (48h), a relative increase was noted in a gene, glutamine-fructose-6-phosphate transaminase 1, reported that overexpression of this gene may lead to the increased resistance to MeHg. To confirm the alteration of these genes in cultured neurons, we then applied real time-RT PCR with SYBR green. Thus, this result suggests that a neurotoxic effect of the MeHg might be ascribed that MeHg alters neuronal receptor regulation or homeostasis of neuronal cells in the early phase. However, in the late phase, it protects cells from neurotoxic effects of MeHg.

• BMB Reports
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• 제44권9호
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• pp.601-606
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• 2011

HMGB1 is associated with human cancers and is an activator of autophagy which mediates chemotherapy resistance. We here show that the mRNA levels of HMGB1 are high in leukemia cells and it is involved in the progression of childhood chronic myeloid leukemia (CML). HMGB1 decreases the sensitivity of human myeloid leukemia cells K562 to anti-cancer drug induced death through up-regulating the autophagy pathway, which is confirmed by the observation with an increase in fusion of autophagosomes and autophagolysosomes. When overexpressing HMGB1, both mRNA levels of Beclin-1, VSP34 and UVRAG which are key genes involved in mammalian autophagy and protein levels of p-Bcl-2 and LC3-II are increased. Luciferase assays document that over-expression of HMGB1 increases the transcriptional activity of JNK and ERK, which may be silenced by siRNA. The results suggest that HMGB1 regulates JNK and ERK required for autophagy, which provides a potential drug target for therapeutic interventions in childhood CML.

• International Journal of Oral Biology
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• 제35권2호
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• pp.69-74
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• 2010

The mu opioid receptor (MOR) has been regarded as the main site of interaction with analgesics in major clinical use, particularly morphine. The repressor element-1 silencing transcription factor (REST) functions as a transcriptional repressor of neuronal genes in non-neuronal cells. However, it is expressed in certain mature neurons, suggesting that it may have complex and novel roles. In addition, the interactions between MOR and REST and their functions remain unclear. In this study, we examined the effects of morphine on the expression of REST mRNA and protein in human neuroblastoma NMB cells to investigate the roles of REST induced by MOR activation in neuronal cells. To determine the effects of morphine on REST expression, we performed RT-PCR, real-time quantitative RT-PCR, western blot analysis and radioligand binding assays in NMB cells. By RTPCR and real-time quantitative RT-PCR, the expression of REST was found to be unchanged by either the MOR agonist morphine or the MOR specific antagonist CTOP. By western blot, morphine was shown to significantly inhibit the expression of REST, but this suppression was completely blocked by treatment with CTOP. In the radioligand binding assay, the overexpression of REST led to an increased opioid ligand binding activity of endogenous MOR in the NMB cells. These results together suggest that morphine inhibits the expression of REST in human neuroblastoma cells through a post-transcriptional regulatory mechanism mediated through MOR.

• Molecules and Cells
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• 제43권4호
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• pp.373-383
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• 2020

Our previous study revealed a novel role of Fas-associated death domain-containing protein (FADD) in islet development and insulin secretion. Insulin-degrading enzyme (IDE) is a zinc metalloprotease that selectively degrades biologically important substrates associated with type 2 diabetes (T2DM). The current study was designed to investigate the effect of FADD phosphorylation on IDE. We found that the mRNA and protein levels of IDE were significantly downregulated in FADD-D mouse livers compared with control mice. Quantitative real-time polymerase chain reaction analysis showed that FADD regulates the expression of IDE at the transcriptional level without affecting the stability of the mRNA in HepG2 cells. Following treatment with cycloheximide, the IDE protein degradation rate was found to be increased in both FADD-D primary hepatocytes and FADD-knockdown HepG2 cells. Additionally, IDE expression levels were reduced in insulin-stimulated primary hepatocytes from FADD-D mice compared to those from control mice. Moreover, FADD phosphorylation promotes nuclear translocation of FoxO1, thus inhibiting the transcriptional activity of the IDE promoter. Together, these findings imply a novel role of FADD in the reduction of protein stability and expression levels of IDE.

• 생명과학회지
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• 제14권5호
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• pp.732-740
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• 2004

MCM 단백질의 암세포내에서 과발현 되는 원인을 규명하기 위하여 mcm7, 2 promoter영역의 전사인자 결합 부위의 역할을 조사하였다. 암세포에서 promoter 활성은 정상세포보다 8배정도 높은 활성을 나타내 특유 전사인자의 존재를 시사하였다. Promoter영 역 에는 E2F 결합부위 와 Myc/Max/Mad단백질 결합 부위로 알려진 I-box가 존재한다. 이들 각각의 변이체 promoter를 작성하여 암세포와 정상세포에서 luciferase reporter 활성을 측정하는 것으로 각 영역의 역할을 검토하였다. 그 결과 정상세포 내에서는 강한 repressor존재 또는 활성을 negative로 조절 할 수 있는 complex의 존재로 promoter활성이 조절되는 반면 암세포 내에서는 I-box에 결합하여 promoter를 활성화시키는 특유 단백질의 존재가 시사되었다.

• Asian-Australasian Journal of Animal Sciences
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• 제25권6호
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• pp.789-793
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• 2012

Fertilization of the oocyte commences embryogenesis during which maternally inherited mRNAs are degraded and the embryonic genome is activated. Transcription of embryonic mRNA is initiated by embryonic genome activation (EGA). RNA polymerase II (RNA Pol II) is responsible for the synthesis of mRNAs and most small nuclear RNAs, and consists of 12 subunits, the largest of which characteristically harbors a unique C-terminal domain (CTD). Transcriptional activity of RNA Pol II is highly regulated, in particular, by phosphorylation of serine residues in the CTD. Here, we have shown the presence of RNA Pol II CTD phosphoisoforms in porcine oocytes and preimplantation embryos. The distribution pattern as well as phosphorylation dynamics in germinal vesicles and during embryogenesis differed in developmental stages with these isoforms, indicating a role of RNA Pol II CTD phosphorylation at the serine residue in transcriptional activation during both oocyte growth and embryonic genome activation. We additionally examined the effects of the RNA Pol II inhibitor, ${\alpha}$-amanitin, on embryo development. Our results show that inhibition of polymerase, even at very early stages and for a short period of time, dramatically impaired blastocyst formation. These findings collectively suggest that the functionality of maternal RNA Pol II, and consequently, expression of early genes regulated by this enzyme are essential for proper embryo development.

• Journal of Microbiology and Biotechnology
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• 제23권12호
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• pp.1785-1790
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• 2013

The synthetic machinery of ATF4 (activating transcription factor 4) is activated in response to various stress conditions involved in nutrient restriction, endoplasmic reticulum homeostasis, and oxidation. Stress-induced inhibition of proteasome activity triggers the unfolded protein response and endoplasmic reticulum stress, where ATF4 is crucial for consequent biological events. In the current study, we showed that the $NAD^+$-dependent deacetylase, SIRT1, suppresses ATF4 synthesis during proteasome inhibition. SIRT1 depletion via transfection of specific siRNA into HeLa cells resulted in a significant increase in ATF4 protein, which was observed specifically in the presence of the proteasome inhibitor MG132. Consistent with SIRT1 depletion data, transient transfection of cells with SIRT1-overexpressing plasmid induced a decrease in the ATF4 protein level in the presence of MG132. Interestingly, however, ATF4 mRNA was not affected by SIRT1, even in the presence of MG132, indicating that SIRT1-induced suppression of ATF4 synthesis occurs under post-transcriptional control. Accordingly, we propose that SIRT1 serves as a negative regulator of ATF4 protein synthesis at the post-transcriptional level, which is observed during stress conditions, such as proteasome inhibition.

• 한국수정란이식학회지
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• 제27권3호
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• pp.175-181
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• 2012

The synovial tissues are a valuable MSCs source for cartilage tissue engineering because these cells are easily obtainable by the intra-articular biopsy during diagnosis. In this study, we isolated and characterized the canine MSCs derived from synovial fluid of female and male donors. Synovial fluid was flushed with saline solution from pre and post-puberty male (cM1-sMSC and cM2-sMSC) and female (cF1-sMSC and cF2-sMSC) dogs, and cells were isolated and cultured in advanced-DMEM (A-DMEM) supplemented with 10% FBS in a humidified 5% $CO_2$ atmosphere at $38.5^{\circ}C$. The cells were evaluated for the expression of the early transcriptional factors, such as Oct3/4, Nanog and Sox2 by RT-PCR. The cells were induced under conditions conductive for adipogenic, osteogenic, and chondrogenic lineages, then evaluated by specific staining (Oil red O, von Kossa, and Alcian Blue staining, respectively) and analyzed for lineage specific markers by RT-PCR. All cell types were positive for alkaline phosphatase (AP) activity and early transcriptional factors (Oct3/4 and Sox2) were also positively detected. However, Nanog were not positively detected in all cells. Further, these MSCs were observed to differentiate into mesenchymal lineages, such as adipocytes (Oil red O staining), osteocytes (von Kossa staining), and chondrocytes (Alcian Blue staining) by cell specific staining. Lineage-specific genes (osteocyte; osteonectin and Runx2, adipocytes; PRAR-${\gamma}2$, FABP and LEP, and chondrocytes; collagen type-2 and Sox9) were also detected in all cells. In this study, we successfully established synovial fluid derived mesenchymal stem cells from female and male dogs, and determined their basic biological properties and differentiation ability. These results suggested that synovial fluid is a valuable stem cell source for cartilage regeneration therapy, and it is easily accessible from osteoarthritic knee.

• 미생물학회지
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• 제36권1호
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• pp.1-7
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• 2000

발광 박테리아인 Photobacterium 종들의 lux 오페론 하부 영역에서 riboflavin 생합성에 관여하는 유전자들(ribⅠ,Ⅱ,Ⅲ,Ⅳ)이 발견되었다. Photobacterium phosphoreum의 lux 유전자와 rib 유전자를 포함하는 intergenic 영역의 단일사슬 DNA가 P. phosphoreum의 mRNA에 의하여 S1 nuclease digestion에서 손상받지 않았으며, ribⅠ에 의하여 암호화되는 P. phosphoreum의 riboflavin synthase의 활성도가 lux-specific한 효소들인 luciferase 혹은 fatty acid reductase 활성도와 같이 bioluminescence intensity의 발현과 함께 대수기 말기에서 증가하는 박테리아 발광반응의 특이한 조절 체계인 'autoinduction' 양상을 보였다. 또한 P. leiognathi의 luxB로부터 ribⅡ까지 포함하는 DNA를 강력한 lux 프로모터와 reporter(chloramphenicol acetyl transferase, CAT) 유전자 사이에 삽입하고 접합(conjugation)의 방법으로 P. leiognathi에 유전자 전이(gene transfer)시켜 CAT reporter 유전자의 발현을 P. leiognathi에서 조사한 바, 그 유전자의 발현 정도에 큰 차이가 없었을 뿐만 아니라 이 구조에서 lux 프로모터를 제거하게 되면 CAT reporter 유전자의 발현이 전혀 나타나지 않았다. 이들 실험 결과들은 lux 유전자와 rib 유전자의 intergenic영역에 lux 오페론의 전사 종결 구조(transcriptional terminator)가 존재하지 않으며 ribflavin 생합성 유전자들이 그들 고유의 프로모터에 의하여 전사되는 것이 아니라 lux 오페론의 프로모터에 의하여 발현됨을 나타내는 것으로, 이는 Photobacterium 종들에서 lux 유전자와 rib 유전자들은 공동의 발현 조절 체계를 갖는 것으로 요약된다.