• 대한바이러스학회지
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• 제28권3호
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• pp.267-274
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• 1998

Human cytomegalovirus (HCMV) has the ability to activate the expression of many viral and cellular genes. Among various viral proteins, the immediate early proteins (IE1-72kDa, IE2-86kDa) have been known to be potent transactivators. The product of c-jun proto-oncogene is important in cell activation and differentiation. Here, we tried to find out if the IE could activate the c-jun promoter and also tried to identify the responsible sequence elements in the c-jun activation by IE1-72kDa. We found HCMV IE expression transactivated the c-jun promoter in human embryonal lung fibroblasts (HEL). The activation fold by IE1-72kDa, IE2-86kDa and IE2-55kDa was 23, 35, and 5, respectively. When the expression of each IE was combined, it showed synergism. Expression of (IE1-72kDa + IE2-86kDa) and (IE1-72kDa + IE2-86kDa + IE2-55kDa) resulted in 131 and 162 fold increase, respectively. The c-jun promoter region between -117 and -59 contains binding sites for the transcription factors Spl, CAAT, AP-l like (ATF/CREB), and MEF2. Transient expression assays were performed using various reporter plasmids containing the c-jun promoter-regulatory region linked to the luciferase gene and a plasmid expressing HCMV IE1 gene. Deletional and point mutational analysis showed that the sequence between -225 to -160 and the CTF binding site were involved in the up-regulation of c-jun promoter.

• 대한바이러스학회지
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• 제29권2호
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• pp.129-136
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• 1999

Transient transfection assay has been done to evaluate whether the c-jun activation would be prerequisite to the induction of permissiveness against human cytomegalovirus using in vitro cell model in which U937 has been induced to express CD11b and CD14 to become potential monocyte/macrophage cells by TPA treatment. U937 cells were treated with $10\;{\mu}M$, $50\;{\mu}M$ or $100\;{\mu}M$ of TPA. The cell morphology change was observed and the expression of the CD11b and CD14 was confirmed by FACS. Differentiated cells were transfected with pJLuc reporter vector which contained the wild type murine c-jun promoter spanning the SP1, CTF, ATF/CREB and MEF-2 binding sites upstream of the firefly luciferase gene. After 48 hrs of transfection, the cells were infected with HCMV Towne strain and the luciferase activity was assessed at 1 hand 4 h pi. The transfection assay showed no activation of the c-jun promoter at 1 h pi, instead, it showed 2 times increase of the its activity at 4 h pi. There was no difference of the c-jun promoter activation between TPA treated and untreated U937 cells, implying that c-jun activation might not be prerequisite for allowing cells to be premissive to HCMV, although HCMV infection itself could activate c-jun promoter.

• 약학회지
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• 제43권1호
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• pp.42-47
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• 1999

Phorbol ester, growth factors activities are mediated by unclear transcription factors, the c-Fos and c-Jun, which can regulate transcriptional activation through specific DNA sites and by forming the transcription factor AP-l, which usually mediates cell proliferation and differentiation signals. We explored effects of Pini Folium extract (API-l) on AP-l activity. Western blot analysis confirmed that API-l decreased levels of c-Fos or c-Jun protein induced by the tumor promoter Phorbol 12-myristate 13-acetate (PMA; 200 nM). Transient transfection assays with a c-fos promoter reporter construct showed that API-l decreased transcription activity by ore than 50~60%. However, treatment of API-l activity studied further. The main substances were fractionated into dichloromethane layer. Futhermore, API-l extract repressed the [$^3H$]-thymidine uptake in C6 glioma cells, indicating that this extract could be included in a new type of modulator in the mitogenesis.

• Archives of Pharmacal Research
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• 제25권3호
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• pp.375-380
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• 2002

Cytochrome P4501A2 (CYP1A2) is a member of the cytochrome P450 family of isozymes involved in the phase I drug metabolism of vertebrates. CYP1A2 is responsible for the activation of a number of aromatic amines to mutagenic and carcinogenic forms. Thus, the level of CYP1A2, which varies among different populations, may determine an individual's susceptibility to these chemicals. We have previously reported on the importance of a cis element named PRB (protected region B) in the regulation of human Cytochrome P4501A2 (CYP1A2) gene, which appeared to act as a positive regulatory element. Closer examination of the PRB sequence (-2218 to -2187 bp) revealed a putative AP-1 binding site, TGACTAA, at -2212 bp (Chung and Bresnick, 1997). To elucidate the role of AP-1 in CYP1A2 regulation, we transiently overexpressed c-Jun and c-Fos transcription factors in human hepatoma HepG2 cells, and examined their influence on the CYP1A2 promoter activity by reporter gene assays. Cotransfection of the c-Jun and the c-Fos expression vectors increased the induced transactivation by five to six fold from the CYP1A2 promoter constructs. However, deletion of the PRB element did not affect the degree of activation by the c-Jun and the c-Fos. Therefore, it is unlikely that the c-Jun and the c-Fos activate the CYP1A2 promoter through this AP-1 consensus-like sequence in the PRB region.

• BMB Reports
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• 제51권1호
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• pp.33-38
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• 2018

Sterol regulatory element-binding protein-1c (SREBP1c) plays an important role in triglyceride (TG) homeostasis. Although our previous study showed that hepatitis C virus core-binding protein 6 (HCBP6) regulates SREBP1c expression to maintain intracellular TG homeostasis, the mechanism underlying this regulation is unclear. In the present study, we found that HCBP6 increased intracellular TG levels by upregulating SREBP1c expression. HCBP6 increased SREBP1c transcription by directly binding to the SREBP1c promoter (at the -139- to +359-bp region). Moreover, we observed that HCBP6 interacted with $C/EBP{\beta}-binding$ site in the SREBP1c promoter both in vitro and in vivo. These results indicate that HCBP6 upregulates human SREBP1c expression by binding to the $C/EBP{\beta}-binding$ site in the SREBP1c promoter.

• BMB Reports
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• 제44권1호
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• pp.70-75
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• 2011

Nucleolar and coiled-body phosphoprotein 1 (NOLC1) is a phosphoprotein that transiently associates with the mature nucleolar H/ACA and C/D box small nucleolar ribonucleoproteins (snoRNPs). Several lines of evidence indicate that NOLC1 plays an important role in the synthesis of rRNA and the biosynthesis of ribosomes. In the present study, we examined the transcriptional regulation mechanisms that govern the expression of NOLC1. We first performed functional dissection of the NOLC1 promoter. We demonstrated that transcription factors NF-${\kappa}B$ and CREB could bind to the minimal NOLC1 promoter. This was demonstrated by electrophoretic mobility shift assays and chromatin immunoprecipitation. Mutagenesis and overexpression assays revealed that NF-${\kappa}B$ and CREB positively regulated the NOLC1 promoter. These findings may provide new insight into the mechanisms that regulate NOLC1 expression.

• Asian Pacific Journal of Cancer Prevention
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• 제16권13호
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• pp.5181-5185
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• 2015

Background: CCAT1 has been reported to be linked with pathogenesis of malignancies including colon cancer and gastric cancer. However, the regulatory effect of CCAT1 in hepatocellular carcinoma (HCC) remains unclear. The purpose of this research was to identify any role of CCAT1 in the progression of HCC. Materials and Methods: Real time-PCR was performed to test the relative expression of CCAT1 in HCC tissues. A computation screen of CCAT1 promoter was conducted to search for transcription-factor-binding sites. The association of c-Myc with CCAT1 promoter in vivo was tested by Pearson correlation analysis and chromatin immunoprecipitation assay. Additionally, Kaplan-Meier analysis and Cox proportional hazards analyses were performed. Results: c-Myc directly binds to the E-box element in the promoter region of CCAT, and when ectopically expressed increases promoter activity and expression of CCAT1. Moreover, Kaplan-Meier analysis demonstrated that the patients with low expression of CCAT1 demonstrated better overall and relapse-free survival compared with the high expression group. Cox proportional hazards analyses showed that CCAT1 expression was an independent prognostic factor for HCC patients. Conclusions: The findings demonstrated CCAT1, acting as a potential biomarker in predicting the prognosis of HCC, is regulated by c-Myc.

• 생명과학회지
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• 제20권11호
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• pp.1603-1610
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• 2010

Fucoidan은 갈조류의 세포벽에 존재하는 황산화 다당류이다. 본 연구에서는 자외선 B를 인체각질형성세포에 조사하여 matrix metalloproteinase-1 (MMP-1)을 발현 시킨 후 Fucus evanescens fucoidan이 MMP-1 promoter, mRNA, 단백 발현과 mitogen-activated protein kinases (MAPKs)의 인산화에 미치는 영향을 확인하고자 하였다. 자외선 B에 의해 생성된 MMP-1의 promoter activity와 mRNA, 단백 발현은 fucoidan $10\;{\mu}g/ml$와 $100\;{\mu}g/ml$를 투여하였을 때 fucoidan을 투여하지 않고 자외선만 조사한 군에 비하여 유의하게 억제되었다. 그리고 F. evanescens fucoidan은 extracellular signal regulated kinase (ERK)의 활성은 현저히 억제시켰으나 c-JUN N-terminal kinase (JNK)와 p38의 활성에 미치는 영향은 약하였다. 따라서 이 연구결과들은 F. evanescens fucoidan이 피부 광노화의 예방과 치료에 도움이 될 가능성을 확인할 수 있었다.

• 생명과학회지
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• 제26권12호
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• pp.1383-1391
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• 2016

타목시펜과 같은 항에스트로젠은 ER 양성의 초기 유방암 환자에게 사용되고 있다. 그러나 대부분의 환자에서 이 항에스트로젠에 대한 내성 발현은 불가피하게 발생한다. BCAR3 유전자는 사람의 에스트로젠 의존성 유방암에서 tamoxifen 내성유도를 야기하는 단백질로 발견되었다. 우리들은 이전에 이 BCAR3 유전자가 세포주기 진행과 EGF와 인슐린에 의한 DNA 합성 신호전달경로를 조절한다고 보고하였다. 본 연구에서는, 비종양성 정상적인 인간유방상피세포인 MCF-12A세포에서 c-Jun 전자의 조절에 대한 BCAR3유전자의 기능적인 역할을 조사하였다. BCAR3의 일시적인 발현 또는 지속적인 발현이 c-Jun mRNA와 단백질의 발현을 증가하는 것을 발견하였다. 또한 BCAR3 발현 유전자의 미세주사에 의해 세포 증식이 증가하였다. 이 c-Jun의 발현 증가는 promoter의 활성화를 통해 일어난다. 또한 BCAR3에 의한 c-Jun 발현 유도가 억제성 Ras, Rac, Rho에 의해 억제되었다. 다음으로 EGF 성장인자에 의한 c-Jun 발현 유도에 대한 BCAR3의 영향을 단일 세포 미세주사법에 의해 조사하였다. BCAR3 항체, BCAR3의 siRNA와 같은 BCAR3의 기능을 억제할 수 있는 물질들을 세포로 미세주사하면 EGF에 의한 c-Jun의 발현을 억제하였지만, IGF-1 성장인자에 의한 c-Jun 발현은 억제하지 않았다. 이러한 결과들로부터 BCAR3는 c-Jun 단백질 발현 유도와 세포 증식에 중요한 역할을 하며, 여기에는 Ras, Rac, Rho와 같은 GTPase들이 필요하다는 것을 발견하였다.

• 생명과학회지
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• 제15권6호
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• pp.928-934
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• 2005

ATF2는 c-Fos와 c-Jun과 같은 전사인자이며 이들은 루신지퍼 단백질이다. 루신지퍼 단백질은 동형이합체 혹은 이형이합체를 형성하며 promoter 영역에 결합하여 전사조절에 중요한 역할을 한다. 세포의 전사인자 ATF2는 ATF/CRE site에 결합하며 특히 선택적인 interfamily 이형이량체를 형성함으로써 전사 조절에 있어서 다양한 메카니즘을 제공할 수 있다. 본 연구에서는 ATF2 cDNA를 6xHis를 가진 expression vector에 subcloning하여 E.cnli BL2l에서 발현시켰다. 6xHis tag은 nickel-chelating chromatography를 가능하게 하였다 발현된 ATF2는 In vitro binding pull-down assay에서 동형이합체를 이를 뿐만 아니라 AP-1 그룹의 인자들과 선택적인 이형이합체를 형성함을 보여 주었다. BATF와는 강하게 결합하였으며 c-Jun과도 안정된 이합체를 형성하였다. 그러나 c-Fos와는 이합체를 형성하지 않으므로서 AP-1그룹 내에서도 이합체 형성이 선택적으로 이루어짐을 알 수 있다.