• 한국발생생물학회지:발생과생식
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• 제15권1호
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• pp.25-30
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• 2011

Embryonic stem (ES) cells can self-renew maintaining the undifferentiated state. Self renewal requires many factors such as Oct4, Sox2, FoxD3, and Nanog. NF-${\kappa}B$ is a transcription factor involved in many biological activities. Expression and activity of NF-${\kappa}B$ increase upon differentiation of ES cells. Reportedly, Nanog protein directly binds to NF-${\kappa}B$ protein and inhibits its activity in ES cells. Here, we found a potential binding site of NF-${\kappa}B$ in the human Nanog promoter and postulated that NF-${\kappa}B$ protein may regulate expression of the Nanog gene. We used human embryonic carcinoma (EC) cells as a model system of ES cells and confirmed decrease of Nanog and increase of NF-${\kappa}B$ upon differentiation induced by retinoic acid. Although deletion analysis on the DNA fragment including NF-${\kappa}B$ binding site suggested involvement of NF-${\kappa}B$ in the negative regulation of the promoter, site-directed mutation of NF-${\kappa}B$ binding site had no effect on the Nanog promoter activity. Furthermore, no direct association of NF-${\kappa}B$ with the Nanog promoter was detected during differentiation. Therefore, we conclude that NF-${\kappa}B$ protein may not be involved in transcriptional regulation of Nanog gene expression in EC cells and possibly in ES cells.

• 한국미생물생명공학회:학술대회논문집
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• 한국미생물생명공학회 2001년도 Proceedings of 2001 International Symposium
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• pp.15-19
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• 2001

Creating an artificial strain with a minimal gene set for a specific purpose is every biologist's dream. With the complete genome sequencing of more than 50 microorganisms and extensive functional analyses of their genes, it is possible to design a genetic blueprint for a simple custom-designed microbe with the minimal gene set. Two different approaches are being considered. The first 'top-down' approach is trimming the genome to a minimal gene set by selectively removing genes of an organism thought to be unnecessary based on microbial genomics. The second 'bottom-up' approach is to synthesize the proposed minimal genome from basic chemical building blocks. The 'top-down' approach starting with the genome of a well known microorganism is more technically feasible, whereas the bottom-up approach may not be attainable in the nearest future because of the lack of the complete functional analysis of the genes needed for a life. Here in this study, we used the top-down approach to minimize the E. coli genome to create an artificial organism with 'core' elements for self-sustaining and self-replicating cells by eliminating unnecessary genes. Using several different kinds of sophisticated deletion techniques combined with a p:1age and transposons, we deleted about 19％ of the E. coli genome without causing any damages to cellular growth. This smaller E. coli genome will be further reduced to a genome with a minimal gene l;et essential for cell life. This minimized E. coli genome can lead to the construction of many custom-designed strains with myriad practical and commercial applications.

• 한국미생물·생명공학회지
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• 제17권3호
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• pp.183-187
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• 1989

일반적으로 Mu phage를 가지고 있는 plasmid를 장내 세균에 삽입시키면 대부분의 Mu에 민감한 세균들은 zygotic induction이 일어나서 recipient cell 들이 살아남지 못하게 된다. 그러나 Mu 저항성 세균을 사용하면 cell이 죽지않고 recipient내에 삽입되는데 그 정확한 현상은 아직 밝혀지지 않았으나 Mu의 복제에 필요한 host의 기능이 결여된 것으로 추정되고 있다. 또한 reverse field electrophoresis를 사용하여 insertion mutant 나 deletion mutant들 의 염색체 및 거대 분자 DNA의 변이를 쉽게 비교 분석할 수가 있다. 본 실험에서는 Mu phage 저항성 C. crescentus를 사용하여 Tn5에 의한 영향 요구성 돌연변이주 출현률 및 운동성 돌연변이주 출현률을 조사한 결과 2%∼3% 수준으로 돌연변이가 일어났으며 이들 변이주들의 염색체를 Dra I 제한효소로 절단한 다음 reverse field electrophoresis로 분석한 결과 영양 요구성 돌연변이 균주들은 Tn5가 여러 위치에, 운동성에 돌연변이를 일으킨 균주들은 유사한 위치에 Tn5가 삽입된 것을 확인할 수 있었으나 hybridization 방법으로 확인한 것처럼 동시에 여러 위치를 확인할 수는 없었다. 그러나 이와 같은 문제들은 전기장의 교차시간 간격을 조절함으로 더 정확하게 확인할 수 있을 것으로 사료된다.

• 한국생명과학회:학술대회논문집
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• 한국생명과학회 2005년도 국제학술심포지움 The 44th Annual Meeting of Korean Society for Life Science
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• pp.23-36
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• 2005

Bax, a mammalian pro-apoptotic member of the Bcl-2 family, induces cell death when expressed In yeast. To investigate whether .Bax expression can induce cell death in plant, we produced transgenic Arabidopsis plants that contained murine Bax cDNA under control of a glucocorticoid-inducible promoter. Transgenic plants treated with dexamethasone, a strong synthetic glucocorticoid, induced Bax accumulation and cell death, suggesting that some elements of cell death mechanism by Bax may be conserved among various orgarusms. Therefore, we developed novel yeast genetic system, and cloned several Plant Bax Inhibitors (PBIs). Here, we report the function of two PBIs In detail. PBIl is ascorbate peroxidase (sAPX). Fluorescence method of dihydrorhodamine123 oxidation revealed that expression of Bax in yeast cells generated reactive oxygen species (ROS), and which was greatly reduced by co-expression with sAPX. These results suggest that sAPX inhibits the generation of ROS by Bax, which in turn suppresses Bax-induced cell death in yeast. PBI2 encodes nucleoside diphosphate kinase (NDPK). ROS stress strongly induces the expression of the NDPK2 gene in Arabidopsis thaliana (AtNDPK2). Transgenic plants overexpressing AtNDPK2 have lower lovels of ROS than wildtype plants. Mutants lacking AtNDPK2 had higher levels of ROS than wildtype. H$_{2O2}$ treatment induced the phosphorylation of two endogenous proteins whose molecular weights suggested they are AtMPK3 and AtMPK6. In the absence of H2O2 treatment, phosphorylation of these proteins was slightly elevated in plants overexpressing AtNDPK2 but markedly decreased In the AtNDPK2 deletion mutant. Yeast two-hybrid and in vitro protein pull-down assays revealed that AtNDPK2 specifically interacts with AtMPK3 and AtMPK6. Furthermore, AtNDPK2 also enhances the MBP phosphorylation activity of AtMPK3 i'n vitro. Finally, constitutive overexpression of AtNDPK2 in Arabidopsis plants conferred an enhanced tolerance to multiple environmental stresses that elicit ROS accumulation In situ. Thus, AtNDPK2 appears to play a novel regulatory role in H2O2-mediated MAPK signaling in plants.

• The Plant Pathology Journal
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• 제23권4호
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• pp.281-286
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• 2007

Interactions between viral proteins and host proteins are essential for virus replication. Especially, translation of viral genes completely depends on the host machinery. In potyviruses, interactions of genome-linked viral protein (VPg) with host translation factors including eIF4E, eIF(iso)4E, and poly(A)-binding protein (PABP) has previously been characterized. In this study, we investigated interactions between Soybean mosaic virus (SMV) viral proteins and host translation factors by yeast two-hybrid system. SMV VPg interacted with eIF4E, eIF(iso)4E, and PABP in yeast two-hybrid system, while SMV helper component proteinase (HC-pro) interacted with neither of those proteins. The interaction between SMV NIb and PABP was also detected. These results are consistent with those reported previously in other potyviruses. Interestingly, we found reproducible and specific interactions between SMV coat protein (CP) and PABP. Deletion analysis showed that the region of CP comprising amino acids 116 to 206 and the region of PABP comprising amino acids 520 to 580 are involved in CP/PABP interactions. Soybean library screening with SMV NIb by yeast two-hybrid assay also identified several soybean proteins including chlorophyll a/b binding preprotein, photo-system I-N subunit, ribulose 1,5-biphosphate carboxylase, ST-LSI protein, translation initiation factor 1, TIR-NBS type R protein, RNA binding protein, ubiquitin, and LRR protein kinase. Altogether, these results suggest that potyviral replicase may comprise a multi-protein complex with PABP, CP, and other host factors.

• Animal Systematics, Evolution and Diversity
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• nspc3호
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• pp.139-146
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• 1992

중합효소연쇄반응(PCR)을 이용한 클로닝 기법과 Taq 염기서열분석법을 사용하여 갑각류에 속하는 뿔물맞이게(Pugettia quadridens)(십각 목, 범배 아목, 게 하목)에 대한 18S 리보솜 RNA 유전자의 1차염기서열을 밝혔다. 본 종의 18S 리보솜 RNA 유전자는 십각류에 속하는 또 다른 종인 두드러기어리게(Oedignathus inermis)보다 46개가 짧은 1837개의 염기로 이루어져 있었다. 염기가 삽입되거나 결실된 부분을 고려하지 않았을때에 두 종간에 염기서열 유사도는 90.8%이었다. 염기서열이 가장 보존적인 부위는 1137-1206(70개) 분위로 이 부위에서는 두 종이 완전히 동일한 염기서열을 보이고 있었고, 변이가 연속적으로 가장 큰 부위는 46-55 부위였고 399-407 부위가 그 다음으로 많은 연속적 변이를 가지고 있었다. 18S 리보솜 RNA 유전자의 1차구조에 있어서 염기서열의 변이는 이 유전자 전체를 통해 고르게 분포하지 않았다.

• 미생물학회지
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• 제35권1호
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• pp.28-34
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• 1999

본 연구에서는 Yeast Artificial Chromosome을 효율적으로 조작하고 유유전자의 기능을 보다 더 용이하게 분석하기 위해 EMCV 바이러스의 IRES 염기서열과 $\beta$-galactosidase를 포함하는 새로운 bicistronic fragmentation vector를 제조하였다. 이 벡터의 폴리클로닝 site에 네 개의희귀한 제한효소 부위를 도입하여 DNA를 용이하게 클로닝할 수 있게 만들었다. 그러므로 원하는 어떤 YAC도 효모세포에서 쉽게 상동 재조함에 의해 절편할 수 있는 장점이 있다. 이 bicistronic fragmentation vector 시스템을 이용하면하나의 메시지로부터 연구하고자 하는 유전자와 $\beta$-galactosidase를 동시에 한 세포에서 발현할 수 있기 때문에 유전자의 발현양상을 쉽게 분석할 수 있는 새로운 도구로 이용할 수 있다.

• 정보과학회 논문지
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• 제42권12호
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• pp.1575-1583
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• 2015

사물인터넷 컴퓨팅의 등장으로 다양한 사물인터넷 디바이스를 통해 사용자에 대한 건강 컨텍스트의 수집과 수집된 건강 컨텍스트를 분석하여 노화진단이 가능해졌다. 하지만, 기존의 노화진단 기법들은 서로 다른 고정된 노화진단요소들을 사용하여 사용자에 따라 획득 가능한 건강 컨텍스트의 가변성을 고려하지 않아서 새로운 노화진단요소의 추가 및 삭제에 대해 동적 대응이 힘들다. 본 논문에서는 다양한 사물인터넷 디바이스를 기반으로 노화진단에 필요한 다양한 노화진단 요소를 수집하고, 사용자마다 가변적인 노화진단 요소의 구성에 따라 동적으로 적응 가능한 노화진단 프레임워크의 기법 및 설계를 제안한다. 제안된 노화진단 프레임워크를 이용하면 획득 가능한 건강 컨텍스트의 가변성과 관계없이 노화진단기법의 적용이 가능하며, 노화진단 요소의 동적 추가 및 삭제가 가능하다.

• Journal of Microbiology
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• 제45권5호
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• pp.466-472
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• 2007

A total of 98 vancomycin-resistant Enterococcus faecium (VREF) isolates (58 isolates from patients and 40 isolates from poultry) were compared based on their antimicrobial susceptibility, Tn1546 element organization, and pulsed-field gel electrophoresis (PFGE) patterns. This comparison aided in determining the relationships between the groups of isolates. All the VREF isolates harbored the vanA gene; however, 29 (29.6%) of the isolates exhibited the VanB phenotype-vanA genotype. Furthermore, the VREF isolates from humans and poultry exhibited distinct antimicrobial resistance patterns. The PCR mapping of the Tn1546 elements exhibited 12 different transposon types (A to L). The VREF isolates of poultry were classified into types A to D, whereas the human isolates were classified into types E to L. A PFGE analysis demonstrated a high degree of clonal heterogeneity in both groups of isolates; however, the distinct VREF clones appeared in each group of isolates. The deletion of the vanX-vanY genes or insertion of IS1216V in the intergenic region from the vanX-vanY genes is directly associated with the incongruence of the VanB phenotype-vanA genotype in human VREF isolates. These data suggest that the VREF isolates exhibit distinct phenotypic and genotypic traits according to their origins, which suggests that no evidence exists to substantiate the clonal spread or transfer of vancomycin resistance determinants between humans and poultry.

• 한국약용작물학회지
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• 제3권1호
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• pp.50-55
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• 1995

체세포배의 생산, 보호 및 저장조건의 구명과 체세포배의 기내분화 및 체세포배 배양식물의 유전변이 여부를 탐색하기 위한 연구를 수행한 결과 MS기본배지 보다 1/2MS배지가 체세포배형성에 가장 효과적이었으며 BA, kinetin처리 모두 $0.1{\sim}1mg/L$에서 체세포배가 발이하여 식물체 형성이 양호하였고 농도가 높을수록 억제되는 경향을 보였으며 shoot의 발근과 신장을 위해서는 IAA처리가 효과적이었다. 1/2MS기본배지에 2.0%의 알진산 용액으로 알진산캡슐을 씌운 체세포배의 기내에서의 식물체형성(전환율)은 $AgNO_3$5mg/l처리가 86%로 가장 앙호하였다 . $5^{\circ}C$에서 3개월 동안 체세포배를 저온저장하여 65%의 발아가 이루어졌으며 저장기간이 길어질수록 발아율이 저하되었다. 체세포배 배앙식물은 RAPD(Randomly Amplified Polymorphic DNA)분석을 통하여 여러 major band 수준에서 DNA polymorphism이 관찰되었다.