• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제33권4호
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• pp.381-385
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• 2007

Bone is a dynamic organ that bone remodeling occurs throughout life and involves the process in which the bone matrix is broken down through resorption by osteoclasts and then built back again through bone formation by osteoblasts. Usually these two processes balance each other and a stable level of bone mass is maintained. We here discuss transcription factors involved in regulating the osteoblast differentiation pathway. Runx2 is a transcription factor which is essential in skeletal development by regulating osteoblast differentiation and chondrocyte maturation. Its companion subunit, Cbf${\beta}$ is needed for an early step in osteoblast differentiation pathway. Whereas Osterix(Osx) is a new identified osteoblast-specific transcription factor which is required for the differentiation of preosteoblasts into more mature and functional osteoblasts. We also discuss other transcription factors, Msx1 and 2, Dlx5 and 6, Twist, and Sp3 that affect skeletal patterning and development. Understanding the characteristics of mice in which these transcription factors are inactivated should help define their role in bone physiology and pathology of bone defects.

• Molecules and Cells
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• 제21권3호
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• pp.376-380
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• 2006

Gene expression is regulated in large part at the level of transcription under the control of sequence-specific transcriptional regulatory proteins. Therefore, the ability to affect gene expression at will using sequencespecific artificial transcription factors would provide researchers with a powerful tool for biotechnology research and drug discovery. Previously, we isolated 56 novel sequence-specific DNA-binding domains from the human genome by in vivo selection. We hypothesized that these domains might be more useful for regulating gene expression in higher eukaryotic cells than those selected in vitro using phage display. However, an unpredictable factor, termed the "context effect", is associated with the construction of novel zinc finger transcription factors--- DNA-binding proteins that bind specifically to 9-base pair target sequences. In this study, we directly selected active artificial zinc finger proteins from a zinc finger protein library. Direct in vivo selection of constituents of a zinc finger protein library may be an efficient method for isolating multi-finger DNA binding proteins while avoiding the context effect.

• 미생물학회지
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• 제49권1호
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• pp.8-16
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• 2013

sndA 유전자(AN3911) 하위에 위치하고 있는 GAL4형 전사인자를 암호화하는 유전자(AN3912)에 대해 분석하였다. 이 전사인자는 Zn(II)2Cys6 binuclear cluster DNA-binding domain 과 전사활성부위를 모두 가지고 있는 전형적 진균 특이 전사인자로서 해당 유전자는 gtfA (gal4 type transcription factor)라 명명되었다. 이 유전자의 ORF는 762개의 아미노산으로 구성되어 있고 3개의 intron이 그 안에 존재하였다. gtfA 유전자의 결실돌연변이는 무성포자생성이 감소하고 대신 유성생식기관이 증가하는 형질을 보여주었다. 과다발현균주는 높은 포도당 농도가 주어지면 유성생식이 늦어지는 형질을 나타내었다. gtfA 유전자는 영양생장 후반부와 유성분화 초기단계에서 높은 발현량을 보이고 전생활사를 통해 비교적 일정하게 발현되었다. gtfA의 전사는 일부 유성(NsdD, VeA) 및 무성(FluG, FadA, SfaD) 분화 조절자들에 의해 크게 영향을 받지 않았다. 반면 GtfA는 nsdC 유전자의 발현을 억제하는 것으로 나타났다. 종합하여 볼 때, GtfA는 분화 결정시기에 nsdC의 발현을 억제함으로써 유성분화보다는 무성분화로 유도되도록 조절 할 것으로 추정된다.

• 한국응용약물학회:학술대회논문집
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• 한국응용약물학회 2003년도 Annual Meeting of KSAP : International Symposium on Pharmaceutical and Biomedical Sciences on Obesity
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• pp.70-70
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• 2003

Estrogen receptor is a ligand-activated transcription factor. Its action depends on the receptor, its ligand, and its coactivator proteins. As a consequence, the concentration of the receptor is a major component that governs the magnitude of the estrogen response. Despite the extensive knowledge on mechanism of estrogen receptor action, regulation of estrogen receptor itself is not very well understood. Estrogen receptor is known to be downregulated under hypoxia leading to inhibition of estrogen receptor mediated transcription activation. We have studied mechanism of loss of estrogen responsiveness under hypoxia. We found that Hif-l${\alpha}$, a major transcription factor regulating hypoxic response, inhibited transcription of estrogen response element driven luciferase gene by expression of HIF-l${\alpha}$/vp16 construct designed to contain transcription activity under normoxia. This loss of estrogen responsiveness appears to be the result of ER${\alpha}$ downregulation. ER${\alpha}$was downregulated at the levels of ligand-biding and protein within l2-24h, and the response was blocked by the proteasome inhibitor MG132, protein synthesis inhibitor cyclohexamide, and tyrosine kinase inhibitor Genistein. These results demonstrate that Hif-l${\alpha}$ downregulates ER${\alpha}$ by proteasome dependent pathway.

• Animal cells and systems
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• 제7권3호
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• pp.173-186
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• 2003

The transition metal cadmium is a serious occupational and environmental toxin. To inhibit cadmium-induced damage, cells respond by increasing the expression of genes that encode stress-responsive proteins. The metal-regulatory transcription factor 1 (MTF-1) is a key regulator of heavy-metal induced transcription of metallothionein-I and II and other genes in mammals and other metazoans. Transcriptional activation of genes by MTF-1 is mediated through binding to metal-responsive elements in the target gene promoters. Phosphorylation of MTF-1 plays a critical role in the cadmium-inducible transcriptional activation of metallothionein and other responses. Studies using inhibitors indicate that multiple kinases and signal transduction cascades, including those mediated by protein kinase C, tyrosine kinase and casein kinase II, are essential for cadmium-mediated transcriptional activation. In addition, calcium signaling is also involved in regulating metal-activated transcription. In several species, cadmium induces heat shock genes. Recently much progress has been made in elucidating the cellular machinery that regulates this metal-inducible gene expression. This review summarizes these recent advances in understanding the role of some known cadmium-responsive genes and the molecular mechanisms that activate metal-responsive transcription factor, MTF-1.

• Animal cells and systems
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• 제2권1호
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• pp.117-122
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• 1998

D-raf, a Drosophila homolog of the human c-raf-1, is known as a signal transducer in cell proliferation and differentiation. A previous study found that the D-raf gene expression is regulated by the DNA replication-related element (DRE)/DRE-binding factor (DREF) system. In this study, we found the sequences homologous to transcription factor C/EBP, MyoD, STAT and Myc recognition sites in the D-raf promoter. We have generated various base substitutional mutations in these recognition sites and subsequently examined their effects on D-raf promoter activity through transient CAT assays in Kc cells with reporter plasmids p5'-878DrafCAT carrying the mutations in these binding sites. Through gel mobility shift assay using nuclear extracts of Kc cells, we detected factors binding to these recognition sites. Our results show that transcription factor C/EBP, STAT and Myc binding sites in D-raf promoter region play a positive role in transcriptional regulation of the D-raf gene and the Myo D binding site plays a negative role.

• 생명과학회지
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• 제18권10호
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• pp.1348-1354
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• 2008

mi transcription factor (MITF)는 비만세포의 분화를 조절하는 중요한 전사인자이다. 특히 MITF는 결합조직형 비만세포에서 일반적으로 발현하는 비만세포 특이적 세린 단백분해효소의 일종인 mMCP-6 유전자의 전사를 조절한다. 본 연구는 마우스 골수유래 배양비만세포에서 mMCP-6 유전자의 전사를 조절하는 MITF이형체를 규명하였다. MITF 이형체들의 발현은 RT-PCR로 확인하였다. IL-3존재 하에서 배양한 점막형 비만세포들은 MITF-A,-E, -H, -Mc 등이 발현하였다. 반면에 SCF존재 하에서 배양한 결합조직형 비만세포들은 MITF-A가 발현하였다. MITF이형체를 과발현시키면 NIH-3T3 세포에서 mMCP-6 promoter를 통한 luciferase 활성을 증가시키고, MC/9 비만세포주에서는 증가된 mMCP-6발현을 유도하였다. 더불어 비만세포에서의 mMCP-6 발현은 MITF-A 고갈로 인하여 유의적으로 억제되었다. MITF-A의 전사활성과 DNA결합은 MITF-E, -H, -Mc 등의 타 이형체들의 결과와 유사하였다. 따라서 본 연구의 결과들은 MITF-A가 마우스 결합조직형 비만세포에서 발현하여 mMCP-6 전사를 조절하는 중요한 이형체임을 제시한다.

• Asian-Australasian Journal of Animal Sciences
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• 제31권3호
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• pp.449-456
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• 2018

Objective: Nanog, a homeodomain protein, has been investigated in humans and mice using embryonic stem cells (ESCs). Because of the limited availability of ESCs, few studies have reported the function and role of Nanog in porcine ESCs. Therefore, in this study, we investigated the location of the porcine Nanog chromosome and its basal promoter activity, which might have potential applications in development of ESCs specific marker as well as understanding its operating systems in the porcine. Methods: To characterize the porcine Nanog promoter, the 5'-flanking region of Nanog was isolated from cells of mini-pig ears. BLAST database search showed that there are two porcine Nanog genomic loci, chromosome 1 and 5, both of which contain an exon with a start codon. Deletion mutants from the 5'-flanking region of both loci were measured using the Dual-Luciferase Reporter Assay System, and a fluorescence marker, green fluorescence protein. Results: Promoter activity was detected in the sequences of chromosome 5, but not in those of chromosome 1. We identified the sequences from -99 to +194 that possessed promoter activity and contained transcription factor binding sites from deletion fragment analysis. Among the transcription factor binding sites, a Sp1 was found to play a crucial role in basal promoter activity, and point mutation of this site abolished its activity, confirming its role in promoter activity. Furthermore, gel shift analysis and chromatin immunoprecipitation analysis confirmed that Sp1 transcription factor binds to the Sp1 binding site in the porcine Nanog promoter. Taken together, these results show that Sp1 transcription factor is an essential element for porcine Nanog basal activity the same as in human and mouse. Conclusion: We showed that the porcine Nanog gene is located on porcine chromosome 5 and its basal transcriptional activity is controlled by Sp1 transcription factor.

• The Plant Pathology Journal
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• 제30권3호
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• pp.236-244
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• 2014

The plant pathogen Fusarium graminearum causes Fusarium head blight in cereal crops and produces mycotoxins that are harmful to animals and humans. For the initiation and spread of disease, asexual and sexual reproduction is required. Therefore, studies on fungal reproduction contribute to the development of new methods to control and maintain the fungal population. Screening a previously generated transcription factor mutant collection, we identified one putative $C_2H_2$ zincfinger transcription factor, pcs1, which is required for both sexual and asexual reproduction. Deleting pcs1 in F. graminearum resulted in a dramatic reduction in conidial production and a complete loss of sexual reproduction. The pathways and gene ontology of pcs1-dependent genes from microarray experiments showed that several G-protein related pathways, oxidase activity, ribosome biogenesis, and RNA binding and processing were highly enriched, suggesting that pcs1 is involved in several different biological processes. Further, overexpression of pcs1 increased conidial production and resulted in earlier maturation of ascospores compared to the wild-type strain. Additionally, the vegetative growth of the overexpression mutants was decreased in nutrient-rich conditions but was not different from the wild-type strain in nutrient-poor conditions. Overall, we discovered that the pcs1 transcription factor positively regulates both conidiation and sexual reproduction and confers nutrient condition-dependent vegetative growth.

• 대한약학회:학술대회논문집
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• 대한약학회 2003년도 Proceedings of the Convention of the Pharmaceutical Society of Korea Vol.1
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• pp.228.2-229
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• 2003

Estrogen Receptor is a ligand-activated transcription factor. The concentration of the receptor is a major component that regulates expression of estrogen-responsive genes. We have studied mechanism of estrogen receptor alpha (ER${\alpha}$) downregulation by HIF-1 using HIF-1${\alpha}$/VP16 constructs. ER${\alpha}$ is known to be downregulated under hypoxic condition. Transcriptional response under hypoxia is mediated through Hypoxia-inducible factor-1 (HIF-1), a transcription factor that is usullaly degraded but stabilized under hypoxia. (omitted)