• 대한화학회지
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• 제59권1호
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• pp.93-96
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• 2015

• Molecules and Cells
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• 제42권10호
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• pp.721-728
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• 2019

Non-structural protein 1 (NS1) of influenza virus has been shown to inhibit the innate immune response by blocking the induction of interferon (IFN). In this study, we isolated two single-stranded RNA aptamers specific to NS1 with $K_d$ values of $1.62{\pm}0.30nM$ and $1.97{\pm}0.27nM$, respectively, using a systematic evolution of ligand by exponential enrichment (SELEX) procedure. The selected aptamers were able to inhibit the interaction of NS1 with tripartite motif-containing protein 25 (TRIM25), and suppression of NS1 enabled retinoic acid inducible gene I (RIG-I) to be ubiquitinated regularly by TRIM25. Additional luciferase reporter assay and quantitative real-time PCR (RT-PCR) experiments demonstrated that suppression of NS1 by the selected aptamers induced IFN production. It is noted that viral replication was also inhibited through IFN induction in the presence of the selected aptamers. These results suggest that the isolated aptamers are strongly expected to be new therapeutic agents against influenza infection.

• Genomics & Informatics
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• 제3권2호
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• pp.77-80
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• 2005

Targeting of complex system such as human cells rather than biochemically pure molecules will be a useful approach to massively identify ligands specific for the markers associated with human disease such as cancer and simultaneously discover the specific molecular markers. In this study, we developed in vitro selection method to identify nuclease-resistant nucleic acid ligands called RNA aptamers that are specific for human cancer cells. This method is based on the combination of the cell-based selection and subtractive systematic evolution of ligands by exponential enrichment (SELEX) method. These aptamers will be useful for cancer-specific ligands for proteomic research to identify cancer-specific molecular markers as well as tumor diagnosis and therapy.

• Biomolecules & Therapeutics
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• 제21권6호
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• pp.423-434
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• 2013

The adoption of oligonucleotide aptamer is well on the rise, serving an ever increasing demand for versatility in biomedical field. Through the SELEX (Systematic Evolution of Ligands by EXponential enrichment), aptamer that can bind to specific target with high affinity and specificity can be obtained. Aptamers are single-stranded nucleic acid molecules that can fold into complex three-dimensional structures, forming binding pockets and clefts for the specific recognition and tight binding of any given molecular target. Recently, aptamers have attracted much attention because they not only have all of the advantages of antibodies, but also have unique merits such as thermal stability, ease of synthesis, reversibility, and little immunogenicity. The advent of novel technologies is revolutionizing aptamer applications. Aptamers can be easily modified by various chemical reactions to introduce functional groups and/or nucleotide extensions. They can also be conjugated to therapeutic molecules such as drugs, drug containing carriers, toxins, or photosensitizers. Here, we discuss new SELEX strategies and stabilization methods as well as applications in drug delivery and molecular imaging.

• Journal of Biosystems Engineering
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• 제39권2호
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• pp.111-114
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• 2014

Purpose: This review aims to introduce aptamers and the methods of its development to improve the sensitivity and selectivity to target bacteria. In this review, we have highlighted current developments and directions in the pathogen detection based on aptamers. Background: Aptamers, the specific nucleic acid sequences, can bind to targets with high affinity and specificity. Some of researches on the use of aptamers for the detection of pathogen have been reported in recent years. Aptamers have more applicability than antibodies for the development of pathogen detection using biosensor; such as easy to synthesis and labeling, lack of immunogenicity, and a low cost of production. However, only few reports on the development and use of aptamers for the detection of pathogen have been published. Review: Aptamers specific to pathogen are obtained by whole-cell systematic evolution of ligands by exponential enrichment (SELEX) process. SELEX process is composed of screening random oligonucleotide bound with target cells, multiple separation and amplification of nucleic acids, final identification of the best sequences. For improving those affinity and selectivity to target bacteria, optimization of multiple separating process to remove unbounded oligonucleotides from aptamer candidates and sorting process by flow cytometry are required.

• Bulletin of the Korean Chemical Society
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• 제26권12호
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• pp.2033-2037
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• 2005

In vitro selection was used to isolate $Mg^{2+}$-dependent self-cleaving ribozymes with cis-cleavage activity from a pre-tRNA library having 40-mer random sequences attached to 5'-end of E. coli $tRNA^{Phe}$. After 8 rounds of SELEX (Systematic Evolution of Ligands by Exponential Enrichment), RNA molecules which can self-cleave at the high concentration of $Mg^{2+}$ were isolated. The selected ribozymes can carry out the self-cleavage reaction in the presence of 100 mM $Mg^{2+}$ but not in 10 mM $Mg^{2+}$. The cleavage sites of the ribozymes are located at +3 and +4 of $tRNA^{Phe}$, compared with +1 position of 5'-end cleavage site of pre-tRNA by RNase P. New RNA constructs deprived of its D stem-loop, anticodon stem-loop, variable loop and T stem-loop, respectively showed the cleavage specificity identical to a ribozyme having the intact tRNA structure. Also, the new ribozyme fused with both a ribozyme and $tRNA^{Leu}$ showed the cleavage activities at the various sites within its sequences, different from two sites of position +3 and +4 observed in the ribozyme with $tRNA^{Phe}$. Our results suggest that the selected ribozyme is not structural-specific for tRNA.

• Bulletin of the Korean Chemical Society
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• 제20권11호
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• pp.1335-1339
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• 1999

The function of 5S rRNA, a constituent of a large subunit of ribosome, is not clearly known yet. To identify RNA motifs interacting with 5S rRNA, and thereby to get an insight into the function of 5S rRNA in the ribosome, a SELEX (Systematic Evolution of Ligands by Exponential Enrichment) experiment was performed. RNA molecules binding to Escherichia coli 5S rRNA were selected from a 48-mer random sequence library through 12 rounds of selection, cloned, and sequenced. Two groups of the selected RNA molecules had the consensus sequences GCGG and GUGAAA, respectively, which are present in the segment, G688 through A696, of E. coli 16S rRNA. The gel mobility shift assay showed that 5S rRNA interacted with the 16S rRNA fragment containing the GCGG and GUGAAA sequences. The enzymatic protection experiment shows that the A29CCUGA34 and G51AAGUG56 sequences of 5S rRNA and the C680AGG683 and G688CGG691 sequences of the 16S rRNA fragment are involved in the interaction between the two RNA molecules. On the basis of this observation, we suggest that 5S rRNA and 16S rRNA play a role for the association of two ribosomal subunits.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2005년도 생물공학의 동향(XVI)
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• pp.88-92
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• 2005

Aptamer is the single-stranded oligonucleotide which binds to various target molecules such as proteins, peptides, lipids and small organic molecules with high affinity and specificity. DNA aptamers specific for the $17{\beta}-estradiol$ were selected by SELEX (Systematic Evolution of Ligands by EXponential enrichment) process from a random DNA library. These DNA aptamers have a high affinity to $17{\beta}-estradiol$ as an endocrine disrupting chemical. Nanowell and $200{\mu}m$ gold electrode were used as substrate for DNA aptamer immobilization and electrochemical analysis. Especially, nanowell gold electrode was fabricated by e-beam lithography. The size of single nanowell is 130nm and 40,000 nanowells were deposited on one gold electrode. The immobilization method was based on the interaction between the biotinylated aptamer and streptavidin deposited on gold electrode previously. Immobilization procedure was optimized by surface plasma resonance (SPR) and electrochemical analysis. After the immobilization of DNA aptamer on streptavidin modified gold electrode, $17{\beta}-estradiol$ solution was treated on aptamer immobilized gold electrode. The current of gold electrode was decreased by the binding of $17{\beta}-estradiol$ to DNA aptamer immobilized on gold electrode. However, in negative control experiments of 1-aminoanthraquinone and 2-methoxynaphthalene, the current was rarely decreased. And more sensitive data was obtained from nanowell gold electrode comparing with $200{\mu}m$ gold electrode.

• Journal of Veterinary Science
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• 제21권5호
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• pp.79.1-79.12
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• 2020

Background: Recently, the pork industry of Thailand faced an epidemic of highly virulent strains of porcine reproductive and respiratory syndrome virus (PRRSV), which spread throughout Southeast Asia, including the Lao People's Democratic Republic and Cambodia. Hence, the rapid and on-site screening of infected pigs on a farm is essential. Objectives: To develop the new aptamer as a biosensor for detection PRRSV which are rapid and on-site screening of infected pig. Methods: New aptamers against PRSSV were identified using the combined techniques of capillary electrophoresis, colorimetric assay by gold nanoparticles, and quartz crystal microbalance (QCM). Results: Thirty-six candidate aptamers of the PRRSV were identified from the systematic evolution of ligands by exponential enrichment (SELEX) by capillary electrophoresis. Only 8 out of 36 aptamers could bind to the PRSSV, as shown in a colorimetric assay. Of the 8 aptamers tested, only the 1F aptamer could bind specifically to the PRSSV when presented with the classical swine fever virus and a pseudo rabies virus. The QCM was used to confirm the specificity and sensitivity of the 1F aptamer with a detection limit of 1.87 × 10¹⁰ particles. Conclusions: SELEX screening of the aptamer equipped with capillary electrophoresis potentially revealed promising candidates for detecting the PRRSV. The 1F aptamer exhibited the highest specificity and selectivity against the PRRSV. These findings suggest that 1F is a promising aptamer for further developing a novel PRRSV rapid detection kit.

• 대한화학회지
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• 제46권2호
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• pp.157-163
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• 2002

$tRNA^{Val}$에 결합하는 RNA 요소들을 확인하기 위해 SELEX 방법을 수행하였다. 양끝에 보존된 primer 서열을 가지고 가운데 무작위의 48-mer 올리고 누클레오티드 영역을 가진 DNA 문고를 T7 RNA 중합효소를 이용하여 전사시켜 얻은 RNA pool을 가지고 $tRNA^{Val}$이 고정된 affinity column을 이용하여 14번의 선별 과정을 거쳐 FNA aptamer들을 선별하였다. 몇몇 aptamer들은 세 가지 rRNA들의 고리 영역에 있는 서열과 유사한 서열을 가졌다: 5S rRNA의 C43GAAC47 서열, 16S rRNA의 G1491AAGU1495와 G1379UUCC1383 서열 그리고 23S rRNA의 C1064UUAG1068, G2110UGUA2114, C2480GACGG2485와 A2600CAGU2604 서열. 이 결과들은 $tRNA^{Val}$가 리보솜에서 5S rRNA, 16S rRNA 및 23S rRNA와 다양하게 상호작용 할 수 있다는 것을 암시한다.