• Rapid Communication in Photoscience
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• v.3 no.4
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• pp.79-80
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• 2014

We characterized the one-electron reduction of oligodeoxynucleotides with a 2-oxopropyl group on a thymine base ($d^{oxo}T$) and applied the reaction to the radiolytic activation of DNAzyme function. We designed a system in which the DNAzyme function of cleaving mRNA was suppressed by introduction of $d^{oxo}T$ into the strand of DNAzyme. Hypoxic X-irradiation led to recovery of the cleavage ability because the 2-oxopropyl group was removed to form unmodified DNAzyme. We characterized the DNAzyme function by monitoring the fluorescence change of fluorophore- and quencher-labeled target strands. We confirmed that the DNAzyme function could be regulated by hypoxic X-irradiation and the reaction of $d^{oxo}T$.

• Applied Science and Convergence Technology
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• v.24 no.5
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• pp.190-195
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• 2015

Here, we demonstrated a $Pb^{2+}$ detecting aptasensor using $Pb^{2+}$-sensitive DNAzyme-conjugated gold nanorods (GNRs). Fluorescent DNA substrates that were initially quenched by GNRs, are released in response to $Pb^{2+}$ ions to give a substantial fluorescence signal. The GNR-tethered DNAzyme is reusable at least three times with a LOD of 50 nM.

• BMB Reports
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• v.51 no.1
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• pp.27-32
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• 2018

Non-small-cell lung cancer (NSCLC) is commonly caused by a mutation in the epidermal growth factor receptor (EGFR) and subsequent aberrant EGFR signaling with uncontrolled kinase activity. A deletion mutation in EGFR exon 19 is frequently observed in EGFR gene mutations. We designed a DNAzyme to suppress the expression of mutant EGFR by cleaving the mutant EGFR mRNA. The DNAzyme (named Ex19del Dz) specifically cleaved target RNA and decreased cancer cell viability when transfected into gefitinib-resistant lung cancer cells harboring EGFR exon 19 deletions. The DNAzyme decreased EGFR expression and inhibited its downstream signaling pathway. In addition to EGFR downregulation, Ex19del Dz containing CpG sites activated Toll-like receptor 9 (TLR9) and its downstream signaling pathway via p38 kinase, causing an immunostimulatory effect on EGFR-mutated NSCLC cells. Thus, dual effects of this DNAzyme harboring the CpG site, such as TLR9 activation and EGFR downregulation, leads to apoptosis of EGFR-mutated NSCLC cells.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2005.11a
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• pp.60-62
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• 2005

• Bulletin of the Korean Chemical Society
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• v.27 no.5
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• pp.657-662
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• 2006

Identification of accessible sites in targeted RNAs is a major limitation to the effectiveness of antisense oligonucleotides. A class of antisense oligodeoxynucleotides, known as the “10-23” DNA enzyme or DNAzyme, which is a small catalytic DNA, has been shown to efficiently cleave target RNA at purine-pyrimidine junctions in vitro. We have designed a strategy to identify accessible cleavage sites in the target RNA, which is hepatitis C virus nonstructural gene 3 (HCV NS3) RNA that encodes viral helicase and protease, from a pool of random DNAzyme library. A pool of DNAzymes of 58 nucleotides-length that possess randomized annealing arms, catalytic core sequence, and fixed 5'/3'-end flanking sequences was designed and screened for their ability to cleave the target RNA. The screening procedure, which includes binding of DNAzyme pool to the target RNA under inactive condition, selection and amplification of active DNAzymes, incubation of the selected DNAzymes with the target RNA, and target site identification on sequencing gels, identified 16 potential cleavage sites in the target RNA. Corresponding DNAzymes were constructed for the selected target sites and were tested for RNA-cleavage in terms of kinetics and accessibility. These selected DNAzymes were effective in cleaving the target RNA in the presence of $Mg^{2+}$. This strategy can be applicable to identify accessible sites in any target RNA for antisense oligonucleotides-based gene inactivation methods.

• Bulletin of the Korean Chemical Society
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• v.34 no.12
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• pp.3543-3544
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• 2013

• Proceedings of the Materials Research Society of Korea Conference
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• 2012.05a
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• pp.55.1-55.1
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• 2012

In the first part of this talk, I will introduce an effort to use gold nanoparticles and UO22+ (uranyl) specific DNAzyme for development of highly sensitive and selective colorimetric uranyl sensors. In addition, I will discuss how DNA aptamers can be delivered by nanoparticles to cancer cell nucleus and released by ultrafast femtosecond pulsed laser for targeted cancer therapy. Finally, I will show how proteins such as streptavidin and myoglobin, or nanoparticles can be precisely aligned on DNA with nanometer resolution via backbone-modified phosphorothioate DNA and bifunctional linkers. These interesting functional and structural properties of DNA can provide new opportunities to develop dynamic DNA structures for potential use as intracellular sensors and drug delivery agents.

• Proceedings of the Korean Society of Life Science Conference
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• 2008.10a
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• pp.19-19
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• 2008

• Proceedings of the Korean Magnetic Resonance Society Conference
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• 2002.08a
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• pp.67-67
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• 2002

• Proceedings of the Korean Society of Life Science Conference
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• 2007.10a
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• pp.56.2-56.2
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• 2007

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