• Parasites, Hosts and Diseases
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• 제44권1호
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• pp.21-26
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• 2006

A shuttle vector for Escherichia coli and Giardia lamblia was modified to produce a reporter plasmid, which monitors the expression of prescribed gene in G. lamblia by measuring its luciferase activity. Promoter regions of the gap2 gene, one of the genes induced during encystation, were cloned into this plasmid, and the resultant constructs were then transfected into trophozoites of G. lamblia. Transgenic trophozoites containing one of the 3 gap2-luc reporters were induced to encystation, and characterized with respect to gap2 gene expression by measuring their luciferase activities. Giardia containing a gap2-luc fusion of 112-bp upstream region showed full induction of luciferase activity during encystation.

• 한국미생물·생명공학회지
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• 제35권3호
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• pp.184-190
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• 2007

대략 2 kb의 크기를 가진 Pichia pastoris phosphoglycerate kinase gene (PGK1)의 프로모터부분을 266bp의 작은 크기로 최소화하여 P. pastoris에 있어 episomal의 새로운 항시적 발현벡터를 제조하였다. P. pastoris의 새로운 항시적 발현벡터를 개발하기 위하여 기존의 Pichia발현벡터인 pGABZB의 GAP프로모터부분을 연속적으로 일정 부분이 절단된 PGK1프로모터에 beta-galactosidase유전자가 결합된 부분으로 치환하였다. LacZ유전자를 reporter유전자로 사용하였을 때에 PGK1프로모터의 발현세기는 다른 항시적 프로모터인 GAP프로모터 보다는 낮았지만 TEF1프로모터 보다는 높았다. 본 논문에서 PGK1 프로모터의 불필요한 부분을 제거함으로서 Pichia에서 외래발현을 위한 새로운 episomal발현벡터인 pPGKZ-E를 제조하였으며 이 것은 P. pastoris에 있어 발현세기를 선택할 수 있는 발현벡터선택의 폭을 넓게 하였다.

• 미생물과산업
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• 제19권4호
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• pp.32-35
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• 1993

ras는 활성화 형태인 GTP bound form과 비활성화 형태인 GDP bound form의 두 형태로 존재하며 두 형태를 매개하는 regulatory protein들에 의해 그 activity가 조절된다. 또한 ras는 GTP와 GDP에 강한 친화성이 있으며 세포내에는 GTP보다 GDP가 더 많이 있어서 평소에는 ras가 GDP와 결합하고 있다가 활성화될때만 GTP와 결합하는 것으로 추정된다. GDP bound ras는 guanine nucloetide exchange protein(GEP)에 의해 활성화된 GTP bound form으로 전환되며 ras의 기능이 발휘된 후에는 GTPase activating protein(GAP)에 의해 비활성화된다. Yeast의 경우 IRA1과 2의 product가 GAP의 역할을 하는 것으로 알려져 있고 CDC25 gene의 product가 GEP의 기능을 담당하는 것으로 알려져 있다. NF1 gene은 Von Recklinghausen Neurofibromatosis Type I 질병을 가진 환자에게서 발견되었는데 부분적으로 sequencing한 결과에 따르면 yeast의 IRA1/2, mammalian GAP gene product와 protein homology가 높은 것으로 나타났다. Yeast의 경우 IRA1/2 gene의 손실이나 mammalian ras gene의 transformation으로 인한 heat shock sensitivity가 NF1 gene(2,3) 혹은 GAP(4)의 expression으로 suppression된 것으로 보아 NF1이 GAP protein으로서 ras를 불활성화 시킨다는 것이 판명되었다. 결론적으로 ras의 활성은 GTP bound 혹은 GDP bound의 양쪽형태를 이동하면서 조절되는데 이 기능은 GAP과 GEP 또는 그의 유사 protein들에 의해 수행되며 이러한 regulatory protein들은 growth factor, cytokine 그리고 protein kinase 같은 signal에 의해 활성화된다고 생각된다. 본 총설에서는 ras protein의 여러가지 성질보다는 ras의 modification과 관련하여 항암제로 사용할 수 있는 ras에 specific한 약품개발의 가능성과 현재 알려진 ras의 inhibitor를 중심으로 논하고자 한다.

• 한국미생물·생명공학회지
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• 제19권6호
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• pp.568-574
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• 1991

효모에서 대랑의 물질생산계를 구축하기 위하여 먼저 여러 종류의 베터의 이용이 가능한 다양한 영양요구성 marker를 지니며 형질전환율이 향상된 효모숙주를 선별 개량하였다. 벡터의 제작에 사용되는 프로모터로는, 효모의 여러 유전자 중에서 그 활성이 매우 높은 해당계의 효소 GAP-DH의 구조 유전자 GAP를 이용하기로 하여, 효모염색체 DNA중에서 GAP 프로모터를 분리하여 이용하기 쉽게 변형하였다. 분리된 GAT promoter의 기능을 검토하기 위하여, reporter로 APase의 구조유전자 PHO5'를 이용하여 세포내의 copy수가 상이한 발현 벡터를 제작하여 GAP 프로모터에 의한 APase의 활성 및 전사산물을 측정한 결과, 정상적인 전사가 이루어 졌으며, 효소활성도 높게 나타났으며, 벡터의 copy수에 의한 효소활성의 차이도 감지되었다.

• KSBB Journal
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• 제11권4호
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• pp.445-452
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• 1996

본 연구에서는 GALl, GALl, GALlO 및 GAP promoter 하류에 reporter 유전자인 K. marxianus의 inulinase 유전자(lNUl)를 연결하여 각각의 재조합 plasmid들을 구축하고, 이들로 형질전환된 S. cerevrswe를 회분배양(YPOG 배지 )하여 외래 유전자 발현에 미치는 promoter의 영향을 비교.검토하 였다. 재조합 효모의 최종 균체농도는 36-39 00600 값을 보여 promoter에 따른 큰 차이를 보이지 않았으나, 포도당 소모기간 동안 비증식속도는 평균 $0.24 h^{-1}$로 유지되다가 galactose 소모기간 동안에 GAL promoter 함유 효모배양의 경우 $0.04-0.06 h^{-1}$, pYIGP 함유 재조합 효모배양은 $0.10 h^{-1}$로 감소하였다. 포도당 고갈 후 inulinase 발현은 시작되었고 균체외 inulinase의 발현 수준은 배양 72시간에 4.3 (GALl promoter), 4.0 (GAL7 promoter), 3.8 (GAL10 promoter) 및 1.6 (GAP promoter) unit/mL에 도달하였다. 평판배지상에서의 활성염색과 회분배양의 결과(최종발현양 및 초기 inulinase 말현속도), inulinase 발현에 미치는 promoter 세기 는 GALl > GALlO > GAL7 > GAP 순임을 알 수 있었다. GAL promoter가 배양말기까지 78 % 이상의 높은 plasmid 안정성을 보인 반면에, GAP promoter의 경우 55%의 낮은 plasmid 안정성을 보였다. 또한, 재조합 inulinase는 promoter 종류에 상관없이 98% 이상 배양액으로 분비되였다.

• Reproductive and Developmental Biology
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• 제34권2호
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• pp.103-109
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• 2010

Functional regulation of a specific tissue or organ is controlled by a number of ways, including local cell-cell interaction. Of several forms of cell-cell junctional complexes, gap junctions are caught a great attention due to a formation of direct linkage between neighboring cells. Gap junctions are consisted of connexin (Cx) isoforms. In the present study, we evaluated expressional profiling of Cx isoforms in the rat initial segment (IS) of the male reproductive tract at different postnatal ages. The presence and expression of 13 Cx isoform mRNAs were determined by semi-quantitative real-time PCR analyses. A total of 8 Cx isoform mRNAs were detected in the IS of the male rats during postnatal development. The highest level of Cx30.3 mRNA was found at 5 months of age, while abundance of Cx31 mRNA was the highest at 1 year of age. Expression of Cx31.1 gene was relatively consistent during the postnatal development. Fluctuation of Cx32 and 37 gene expression was observed during the postnatal period. Significant elevation of Cx40 mRNA abundance was detected at 25 days of age and older ages. Expression patterns of Cx43 and 45 genes were similar with the highest level at 2 weeks of age, followed by gradual decreases at older ages. These results indicate differential regulation on expression of Cx isoforms in the rat IS during postnatal development. A complicated regulation of gene expression of Cx isoforms in the IS at different postnatal ages is suggested.

• 한국미생물·생명공학회지
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• 제23권2호
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• pp.138-144
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• 1995

The cDNA, encoding human lysozyme (HLY) which was isolated from a human placenta cDNA library, has been well characterized (Yoshimura et al., 1988). Based on the communication, we have prepared an artificial HLY gene from chemically synthesized 38-oligomer with high codon usage in Saccharomyces cerevisiae. For directing the synthesis and secretion of HLY in S. cerevisiae, an expression vector, pHKl was constructed by inserting the HLY gene, containing a synthetic HLY secretion signal sequence, between the yeast GAP promoter and PH05 terminator. From a lysoplate assay, we have confirmed an yeast transformant harboring a pHK1 which makes a clearing zone on the overlayed Micrococcus luteus. This result means a chemically synthesized HLY gene which was normally expressed and secreted in yeast.

• The Korean Journal of Physiology and Pharmacology
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• 제10권5호
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• pp.263-271
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• 2006

Since astrocytes were shown to play a central role in maintaining neuronal viability both under normal conditions and during stress such as ischemia, studies of the astrocytic response to stress are essential to understand many types of brain pathology. The micro array system permitted screening of large numbers of genes in biological or pathological processes. Therefore, the gene expression patterns in the in vitro model of astrocytes following exposure to oxygen-glucose deprivation (OGD) were evaluated by using the micro array analysis. Primary astrocytic cultures were prepared from postnatal Swiss Webster mice. The cells were exposed to OGD for 4 hrs at $37^{\circ}C$ prior to cell harvesting. From the cultured cells, we isolated mRNA, synthesized cDNA, converted to biotinylated cRNA and then reacted with GeneChips. The data were normalized and analyzed using dChip and GenMAPP tools. After 4 hrs exposure to OGD, 4 genes were increased more than 2 folds and 51 genes were decreased more than 2 folds compared with the control condition. The data suggest that the OGD has general suppressive effect on the gene expression with the exception of some genes which are related with ischemic cell death directly or indirectly. These genes are mainly involved in apoptotic and protein translation pathways and gap junction component. These results suggest that microarray analysis of gene expression may be useful for screening novel molecular mediators of astrocyte response to ischemic injury and making profound understanding of the cellular mechanisms as a whole. Such a screening technique should provide insights into the molecular basis of brain disorders and help to identify potential targets for therapy.

• Journal of Korean Neurosurgical Society
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• 제49권1호
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• pp.13-19
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• 2011

Objective: The purpose of this study is to investigate the combined effects of ginkgo biloba extract, ginkgolide A and B and aspirin on SK-N-MC, human neuroblastoma cell viability and mRNA expression of growth associated protein43 (GAP43), Microtubule-associated protein 2 (MAP2), B-cell lymphoma2 (Bcl2) and protein53 (p53) gene in hypoxia and reperfusion condition. Methods: SK-N-MC cells were cultured with Dulbecco's Modified Eagle's Medium (DMEM) media in $37^{\circ}C$, 5% $CO_2$ incubator. The cells were cultured for 8 hours in non-glucose media and hypoxic condition and for 12 hours in normal media and $O_2$ concentration. Cell survival rate was measured with Cell Counting Kit-8 (CCK-8) reagent assay. Reverse transcriptase polymerase chain reaction (RT-PCR) was used to estimate mRNA levels of GAP43, MAP2, Bcl2, and p53 genes. Results: The ginkgolide A and B increased viable cell number decreased in hypoxic and reperfused condition. The co-treatment of ginkgolide B with aspirin also increased the number of viable cells, however, there was no additive effect. Although there was no increase of mRNA expression of GAP43, MAP2, and Bcl2 in SK-N-MC cells with individual treatment of ginkgolide A, B or aspirin in hypoxic and reperfused condition, the co-treatment of ginkgolide A or B with aspirin significantly increased GAP43 and Bcl2 mRNA levels. In MAP2, only the co-treatment of ginkgolide A and aspirin showed increasing effect. The mRNA expression of p53 had no change in all treating conditions. Conclusion: This study suggests that the combined treatments of Ginkgo biloba extracts and aspirin increase the regeneration of neuroblastoma cells injured by hypoxia and reperfusion.

• Molecular & Cellular Toxicology
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• 제4권3호
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• pp.183-191
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• 2008

Volatile organic compounds (VOCs) are common constituents of cleaning and degreasing agents, paints, pesticides, personal care products, gasoline and solvents. And VOCs are evaporated at room temperature and most of them exhibit acute and chronic toxicity to human. Benzene is the most widely used prototypical VOC and the toxic mechanisms of them are still unclear. The multi-step process of toxic mechanism can be more fully understood by characterizing gene expression changes induced in cells by toxicants. In this study, DNA microarray was used to monitor the expression levels of genes in HepG2 cells and HL-60 cells exposed to the benzene on IC20 and IC50 dose respectively. In the clustering analysis of gene expression profiles, although clusters of HepG2 and HL-60 cells by benzene were divided differently, expression pattern of many genes observed similarly. We identified 916 up-regulated genes and 1,144 down-regulated genes in HepG2 cells and also 1,002 up-regulated genes and 919 down-regulated genes in HL-60 cells. The gene ontology analysis on genes expressed by benzene in HepG2 and HL-60 cells, respectively, was performed. Thus, we found some principal pathways, such as, focal adhesion, gap junction and signaling pathway in HepG2 cells and toll-like receptor signaling pathway, MAPK signaling pathway, p53 signaling pathway and neuroactive ligand-receptor interaction in HL-60 cells. And we also found 16 up-regulated and 14 down-regulated commonly expressed total 30 genes that belong in the same biological process like inflammatory response, cell cycle arrest, cell migration, transmission of nerve impulse and cell motility in two cell lines. In conclusion, we suggest that this study is meaningful because these genes regarded as strong potential biomarkers of benzene independent of cell type.