• Korean Journal of Microbiology
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• v.40 no.3
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• pp.226-229
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• 2004

Histone deacetylase (HDAC) removes acetyl group in lysine residue of histone protein, which is transferred by histone acetylase. HDAC is important in the stabilization and regulation of gene expression in eukaryotic organisms. PCR has been carried out to clone HDAC genes using cDNA library and genomic DNA as the templates from Ganoderma lucidum isolated in Korea. One 470 bp cDNA gene fragment, and 3 genomic HDAC fragments (585 bp, 589 bp, 630 bp) were amplified. When their deduced amino acid sequences were compared with other fungal HDACs, they showed 59-72％ homology.

• Proceedings of the Korean Society of Life Science Conference
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• 2003.05a
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• pp.38-47
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• 2003

처음으로 real time으로 유전자 발현을 visualization할 수 있는 marker를 이용할 수 있게 되었다. 이 maker가 바로 green fluorescent protein(GFP; 녹색형광단백질)이다. GFP는1962년 Shimomura 등에 의하여 해파리인 Aequorea victoria에 존재함이 밝혀졌다(1). 그러나 30년이 지난 1992년이 되어서야 Plasher등에 의하여 GFP의 cDNA가 클로닝 되었고(2) 이후 지금까지 약 10년 동안 GFP는 생명과학분야에서 가장 각광받는 유용한 단백질 중의 하나가 되어 매우 다양한 연구에 응용이 되고 있다. 이렇게 GFP가 생명과학분야에서각광을 받게 된 이유로는 GFP가 모든 외래의 세포에서 형광을 발할 수 있는 활성을 가진 형태로 발현되기 때문이다(3). Chalfie 등은 처음으로 GFP를 대장균과 Caenorhabditis elegans에서 발현시켜 유전자의 발현을 모니터함으로써 GFP를 원핵 및 진핵세포 모두에서 사용할 수 있다는 것을 보고하였다(3), 이러한 발견을 통하여 GFP는 살아있는 세포, 조직 및 생물체에 해를 주지 않고 (non-invasive) 유전자의 발현을 측정하는 marker로서 사용할 수 있게 되어 cell biology, developmental biology, neurobiology 및 cytology 등의 연구분야에 널리 이용되고 있다.

• Proceedings of the Korea Society of Poultry Science Conference
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• 2004.11a
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• pp.11-12
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• 2004

Peroxiredoxin(PRX)은 원핵세포에서 진핵세포에 이르기까지 세포 내부적으로 발생된 과산화물로부터 자신을 보호하는 중요한 항산화단백질이다. 포유류에서는 아직까지 여섯 개의 다른 동형체가 밝혀졌으며, 조류에서는 아직 발표된 바가 없다. 이 실험을 통해 최초로 조류의 PRX 단백질군들의 특성을 분석하였다. 생물정보분석기법을 통해 알아본 결과, 조류에서는 최소한 진화적으로 보존된 4개의 다른 PRX 단백질로 구성됨을 알 수 있다. 또한 닭의 PRXs로 in vitro 실험을 진행한 결과, 포유류의 것과 비슷한 항산화 활성을 나타냄을 알 수 있었다. 닭의 PRX는 조직 비특이적으로 발현하였으며, 이는 항산화 물질의 피해로부터 모든 조직을 보호하기 위한 필수적 요소이기 때문일 것으로 추정된다. 결론적으로, 생물정보분석기법을 통하여 추정할 수 있는 닭의 기능성 유전자군을 효과적으로 찾을 수 있고, in vitro 실험을 통하여 그 기능을 확인할 수 있었다.

• Journal of Life Science
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• v.20 no.12
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• pp.1777-1783
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• 2010

Plants generate reactive oxygen species (ROS) as a by-product of normal aerobic metabolism or when exposed to a variety of stress conditions, which can cause widespread damage to biological macromolecules. To protect themselves from oxidative stress, plant cells are equipped with a wide range of antioxidant proteins. However, the detailed reaction mechanisms of these are still unknown. Peroxiredoxins (Prxs) are ubiquitous thiol-containing antioxidants that reduce hydrogen peroxide with an N-terminal cysteine. The active-site cysteine of peroxiredoxins is selectively oxidized to cysteine sulfinic acid during catalysis, which leads to inactivation of peroxidase activity. This oxidation was thought to be irreversible. Recently identified small protein sulphiredoxin (Srx1), which is conserved in higher eukaryotes, reduces cysteine.sulphinic acid in yeast peroxiredoxin. Srx1 is highly induced by $H_2O_2$-treatment and the deletion of its gene causes decreased yeast tolerance to $H_2O_2$, which suggest its involvement in the metabolism of oxidants. Moreover, Srx1 is required for heat shock and oxidative stress induced functional, as well as conformational switch of yeast cytosolic peroxiredoxins. This change enhances protein stability and peroxidase activity, indicating that Srx1 plays a crucial role in peroxiredoxin stability and its regulation mechanism. Thus, the understanding of the molecular basis of Srx1 and its regulation is critical for revealing the mechanism of peroxiredoxin action. We postulate here that Srx1 is involved in dealing with oxidative stress via controlling peroxiredoxin recycling in Arabidopsis. This review article thus will be describing the functions of Prxs and Srx in Arabidopsis thaliana. There will be a special focus on the possible role of Srx1 in interacting with and reducing hyperoxidized Cys-sulphenic acid of Prxs.

• Journal of Life Science
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• v.30 no.7
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• pp.625-629
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• 2020

The Ocean is a rich source of diverse living organisms include viruses. In this study, we examined the microbial communities in the sea adjacent to Jeju Island in two seasons by metatranscriptomics. We collected and extracted total RNA, and, using the next-generation sequencing HiSeq 2000 and de novo transcriptome assembly, we identified 652,984 and 163,759 transcripts from the March and December samples, respectively. The most abundant organisms in March were bacteria, while eukaryotes were dominant in the December sample. The bacterial communities differed between the two samples, suggesting seasonal change. To identify the viruses, we searched the transcripts against a viral reference database using MegaBLAST with the most identified being bacteriophages infecting the marine bacteria. However, we also revealed an abundance of transcripts associated with diverse herpesviruses in the two transcriptomes, indicating the presence or possible threat of infection of fish in the sea around Jeju Island. This data is valuable for the study of marine microbial communities and for identifying possible viral pathogens.

• Korean Journal of Microbiology
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• v.53 no.4
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• pp.292-296
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• 2017

In eukaryote, THO/TREX complex plays a critical role in transcriptional elongation, pre-mRNA processing, and nuclear mRNA export. This complex is evolutionally well- conserved, but there are some differences in composition and function according to organisms. Here we showed that spTex1, a component of THO/TREX complex, is not essential for growth and mRNA export in a fission yeast, Schizosaccharomyces pombe, which is more similar to higher eukaryote than budding yeast. Deletion and overexpression of the spTex1 gene do not lead to any detectable growth phenotype and accumulation of poly(A)+ RNA in the nucleus. And the spTex1-GFP protein is localized mainly in the nucleus. Yeast two-hybrid and Co-immunoprecipitation analysis showed that the spTex1 protein interacted with spHpr1 (THOC1) and spTho2 (THOC2), main subunits of THO complex. We conclude that the S. pombe Tex1 is a component of THO/TREX complex, but does not plays important roles in growth and bulk mRNA export from the nucleus.

• Applied Biological Chemistry
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• v.42 no.2
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• pp.123-127
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• 1999

Iron is an essential nutrient but potentially toxic element in human. To identify the effects of iron on the gene expression of mammalian cell, we have isolated several genes that are regulated by iron using the RNA differential display method. RNAs were isolated from HeLa cells treated with iron supplement or iron chelator. A total of 24 genes were isolated and of these, four genes were identified by DNA sequencing and northern blot.

• Journal of Life Science
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• v.8 no.2
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• pp.119-125
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• 1998

Column-purified double-stranded RNA binding factor (RBF) protein was tested for its binding affinity for the different forms of nucleic acids structure such as single-stranded(ss) and double-stranded(ds)RNA and ss- and dsDNA. The RBF protein was incubated with each of these nucleic acid structures in separate reactions and its comparative binding affnity was visualized by SDS-polyacrylamide gel electrophoresis. The RBF protein bound to the dsRNA molecule to form a tight RNA:protein complex in agreement with previous studies, but not to the other nucleic acid molecules confirming its distinctive affinity for the dsRNA structure. In phosphorylation assay in vito, the purified RBF protein significantly inhibited the autophosphorylation of the PKR derived from not only human but mouse source in the presence of poly(I):poly(C). It is suggesting that PKR vs. RBF is similarly under a competitive interaction among different eukaryotic organisms during protein synthesis.

• Proceedings of the Korean Society of Developmental Biology Conference
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• 2003.10a
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• pp.112-112
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• 2003

Telomere란 진핵세포에 존재하는 DNA-protein 복합체로서 염색체의 말단부에 tandem repeated DNA 서열 (TTAGGG)과 특정 단백질로 구성되어 있으며 세포 분열이 진행함에 따라 이의 길이가 짧아지게 되고 일정 길이 이하가 되면 세포의 사망이 유발된다. 반면 telomerase는 ribonucleoprotein으로서 telomeric DNA의 합성에 관여하는 것으로 염색체의 말단에 telomeric DNA의 소실을 보충하는 역할로 알려져 있다. 최근 암, 노화 등과 관련하여 telomere 및 telomerase의 연구들이 활발히 진행되고 있으며, 다양한 세포들에 있어 이들의 존재와 역할에 대해서도 많은 연구들이 수행되고 있다. 포유동물의 초기 배자에 있어 telomere의 분포 양상과 telomerase의 activity의 분석은 배 발생의 기작과 배자의 세포적 특성을 구명하는데 매우 중요한 과제라 사료된다. 따라서 본 연구에서는 마우스의 초기 배 발생 단계별 수정란의 telomeric DNA의 분포 양상과 각 단계별 배자들의 telomerase activity를 제시하고자 하였다. 시험에 공시된 마우스는 4-6주령된 ICR계통으로 이들을 과배란 처리 후 자연 교배시켜 얻은 2-, 4-, 8-세포기배, 상실배 및 배반포배를 대상으로 하였다. Telomeric DNA의 양적 분석은 각 발생단계별 수정란의 표본을 제작하고 human telomere repeat probe를 이용하여 FISH (fluorescence in situ hybridization)를 시행하였으며, 분리된 할구들을 형광현미경으로 관찰 후 상을 포착하고 image analyser program (MataMorph, UIC, USA)을 이용하여 한 개의 세포내 telomere의 상대적 함량을 분석하였다. 발생 단계별 배자의 telomerase activity의 분석은 TRAP (telomeric repeat amplofication protocol) assay로 분석한 바 각 발생 단계별 30개의 수정란으로부터 핵 단백질을 추출하여 telomerase를 신장시키고 PCR을 시행한 후 15% PAGE gel loading하여 이의 activity를 확인하였다. 분석 결과, telomeric DNA의 함유율은 발생단계별 다소의 차이를 나타내었으며 telomerase activity는 모든 발생단계의 수정란에서 확인할 수 있었고, 특히 상실배부터 높게 나타남을 확인하였다.

• Korean Journal of Microbiology
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• v.41 no.3
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• pp.157-163
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• 2005

The acetate kinase gene from the copepod Paracyclopina nana was cloned. The open reading frame (ORF) was 1,200 bp, and poly(A) signal sequence was located in the end of the ORF. After the molecular phylogenetic analysis of P nana acetate kinase gene, it was revealed that it formed the same branch with that of Aspergillus. Also P. nana acetate kinase showed the difference with those of other prokaryotic microorganisms but showed the same clade with those of fungi. We also confirmed that the recombinant protein of P. nana acetate kinase made approximately 50 kDa after expression of recombinant gene construct in E. coli. This may be useful to compare this protein to those of other organisms in biochemical characteristics.