• Animal cells and systems
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• v.8 no.1
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• pp.49-55
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• 2004

In vertebrates, multisubunit cofactors regulate gene expression through interacting with cell-type- and gene-specific DNA-binding proteins in a chromatin-selective manner. ADD1/SREBP1c regulates fatty acid metabolism and insulin-dependent gene expression through binding to SRE and E-box motif with dual DNA binding specificity. Although its transcriptional and post-translational regulation has been extensively studied, its regulation by interacting proteins is not well understood. To identify cellular proteins that associate with nuclear form of ADD1/SEBP1c, we employed the GST pull-down system with Hela cell nuclei extract. In this study, we demonstrated that Ku proteins interact specifically with ADD1/SREP1c protein. GST pull-down combined with peptide sequencing analysis revealed that Ku80 binds to ADD1/SREBP1c in vitro. Additionally, western blot analysis showed that Ku70, a heterodimerizing partner of Ku80, also associates with ADD1/SREBP1c. Furthermore, co-transfection of Ku70/Ku80 with ADD1/SREBP1c enhanced the transcriptional activity of ADD1/SREBP1c. Taken together, these results suggest that the Ku proteins might be involved in the lipogenic and/or adipogenic gene expression through interacting with ADD1/SREBP1c.

• Korean Journal of Acupuncture
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• v.18 no.1
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• pp.11-20
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• 2001

Cancer chemoprevention refer to the use of natural or synthetic substances to prevent the initiational and promtional events that occur during the process of carcinogenesis. The effect of Prunella Herba Vulgaris L. Aqua-acupuncture Solution (PVAS) and Prunella Herba Vulgaris L. Water-extracted Solution (PVWS) on the induction of phase II detoxification enzyme (quinone reductase, Glutathione S-transferase) and inhibition of phase I enzyme (cytochrome P4501A1) and benzo[a]pyrene-DNA adduct formation was examined. PVAS is potent inducers of quinone reductase activity. Glutathione levels were increased with PVAS, in cultured murine hepatoma Hepa1c1c7 cells. In addition glutathione S-transferase levels were increased with PVAS. However, there was 45.2% inhibition in the activity of cytochrome P4501A1 enzyme with the treatment of PVAS, $5{\times}$. At concentration of $1{\times}$ and $3{\times}$ of PVAS, the binding of $[^3H]B[a]P$ metabolites to DNA of NCTC-clone 1469 cell was inhibited by 25.3%, 45.0%, respectively. These results suggest that PVAS has chemopreventive potential by inducing quinone reductase and glutathione S-transferase activities, increasing GSH levels, inhibiting the activity of cytochrome P4501A1 and benzo[a]pyrene-DNA adduct formation.

• Proceedings of the PSK Conference
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• 2002.10a
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• pp.318.1-318.1
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• 2002

We found that 23-hydroxyursolic acid, triterpenoid was isolated from Cussonia bancoensis have a significant cytotoxic activity against HL -60 human promyelocytic leukemia cells. The IC of 23-hydroxyursolic acid was 32.83 $\mu$M. These anti-proliferative activity was due to induction of apoptosis. The effect of apoptosis was identified by DNA laddering, DAPI assay. PI staining, and Annerxin V-FITC binding assay. (omitted)

• Interdisciplinary Bio Central
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• v.2 no.3
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• pp.8.1-8.5
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• 2010

Introduction: Recently identified human homologues of ALKB protein have shown the activity of DNA damaging drugs, used for cancer therapy. Bioinformatics study of hABH2 and hABH3 had led to the discovery of a novel DNA repair mechanism. Very little is known about structure and function of hABH4, one of the members of this superfamily. Therefore, in present study we are intended to predict its structure and function through various bioinformatics tools. Materials and Methods: Modeling was done with modeler 9v7 to predict the 3D structure of the hABH4 protein. This model was validated with the program Procheck using Ramachandran plot statistics and was submitted to PMDB with ID PM0076284. The 3d2GO server was used to predict the functions. Residues at protein ligand and protein RNA binding sites were predicted with 3dLigandSite and KYG programs respectively. Results and Discussion: 3-D model of hABH4, ALKBH4.B99990003.pdb was predicted and evaluated. Validation result showed that 96.4 % residues lies in favored and additional allowed region of Ramachandran plot. Ligand binding residues prediction showed four Ligand clusters, having 24 ligands in cluster 1. Importantly, conserved pattern of Glu196-X-Pro198- Xn-His254 in the functional domain was detected. DNA and RNA binding sites were also predicted in the model. Conclusion and Prospects: The predicted and validated model of human homologue hABH4 resulted from this study may unveil the mechanism of DNA damage repair in human and accelerate the research on designing of appropriate inhibitors aiding in chemotherapy and cancer related diseases.

• Rapid Communication in Photoscience
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• v.3 no.4
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• pp.81-84
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• 2014

To examine the microenvironmental effect of DNA on the photosensitized reaction, the electron-donor-connecting porphyrin, meso-(9-phenanthryl)-tris(N-methyl-p-pyridinio) porphyrin (Phen-TMPyP), was synthesized. Phen-TMPyP can bind to oligonucleotides with two binding modes, depending on the DNA concentration. The fluorescence lifetime measurement of Phen-TMPyP shows a shorter component than that of the reference porphyrin without the phenanthryl moiety. However, the observed value is much longer than those of previously reported similar types of electron-donor-connecting porphyrins, suggesting that electron-transfer quenching by the phenanthryl moiety is not sufficient. The fluorescence quantum yield of Phen-TMPyP ($5{\mu}M$) decreased with an increase in DNA concentration of up to $5{\mu}M$ base pair (bp), possibly due to self-quenching through an aggregation along the DNA strand, increased with an increase in DNA concentration of more than $5{\mu}M$ bp and reached a plateau. The fluorescence quantum yield of Phen-TMPyP with a sufficient concentration of DNA was larger than that of the reference porphyrin. The singlet oxygen ($^1O_2$) generating activity of Phen-TMPyP was confirmed by the near-infrared emission spectrum measurement. The quantum yield of $^1O_2$ generation was decreased by a relatively small concentration of DNA, possibly due to the aggregation of Phen-TMPyP, and recovered with a sufficient concentration of DNA. The recovered quantum yield was rather smaller than that without DNA, indicating the quenching of $^1O_2$ by DNA. These results show that a DNA strand can stabilize the photoexcited state of a photosensitizer and, in a certain case, suppresses the $^1O_2$ generation.

• Journal of Acupuncture Research
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• v.23 no.2
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• pp.47-59
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• 2006

We previously found that cobrotoxin inhibited $NF-{\kappa}B$ activity by reacting with signal molecules of $NF-{\kappa}B$ which is critical contributor in cancer cell growth by induction of apoptotic cell death. We here investigated whether cobrotoxin inhibits cell growth of human prostate cancer cells through induction of apoptotic cell death, which is related with the suppression of the $NF-{\kappa}B$ activity. Cobrotoxin $(0{\sim}8\;nM)$ inhibited prostate cancer cell growth through increased apoptosis in a dose dependent manner. Cobrotoxin inhibited DNA binding activity of $NF-{\kappa}B$, an anti-apoptotic transcriptional factor. Consistent with the induction of apoptosis and inhibition of $NF-{\kappa}B$, cobrotoxin increased the expression of pro-apoptotic proteins caspase 3. Cobrotoxin, a venom of Vipera lebetina turanica, is a group of basicpeptides composed of 233 amino acids with six disulfide bonds formed by twelve cysteins. NF-kB is activated by subsequent release of inhibitory IkB and translocation of p50. Since sulfhydryl group is present in kinase domain of p50 subunit of NF-kB, cobrotoxin could modify NF-kB activity by protein-protein interaction. And Cobrotoxin down regulated Akt signals. Salicylic acid as a reducing agent of Sulf-hydryl group and LY294002 as a Akt inhibitor abrogated cobrotoxin-induced cell growth and DNA binding activity of $NF-{\kappa}B$. These findings suggest that nano to pico molar range of cobrotoxin could inhibit prostate cancer cell growth, and the effect may be related with the induction of apoptotic cell death through Akt dependent inhibition of $NF-{\kappa}B$ signal.

• BMB Reports
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• v.42 no.11
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• pp.737-742
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• 2009

Hypoxia-inducible factor-$1{\alpha}/{\beta}$ (HIF-$1{\alpha}/{\beta}$) is a heterodimeric transcriptional activator that mediates gene expression in response to hypoxia. HIF-$1{\alpha}$ has been noted as an effective therapeutic target for ischemic diseases such as myocardiac infarction, stroke and cancer. By using a yeast two-hybrid system and a random peptide library, we found a 16-mer peptide named F29 that directly interacts with the bHLH-PAS domain of HIF-$1{\alpha}$. We found that F29 facilitates the interaction of the HIF-$1{\alpha/\beta}$ heterodimer with its target DNA sequence, hypoxia-responsive element (HRE). The transient transfection of an F29-expressing plasmid increases the expression of both an HRE-driven luciferase gene and the endogenous HIF-1 target gene, vascular endothelial growth factor (VEGF). Taken together, we conclude that F29 increases the DNA-binding ability of HIF-$1{\alpha}$, leading to increased expression of its target gene VEGF. Our results suggest that F29 can be a lead compound that directly targets HIF-$1{\alpha}$ and increases its activity.

• BMB Reports
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• v.34 no.1
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• pp.28-32
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• 2001

The Fos-Jun heterodimers are part of the regulatory network of gene expression and nuclear proteins encoded by proto-oncogenes. The activation of Fos-Jun is important in the transmission of the tumor-promoting signal from the extracellular environment to the nuclear transcription mechanism. To search for the inhibitors of the Fos-Jun DNA complex formation, several natural products were screened and water-soluble paeoniflorin reduced the binding activity of the Fos-Jun heterodimer. This active compound was purified by silica gel column chromatography and HPLC. The electrophoresis mobility shift assay and reverse-phase HPLC test showed that paeoniflorin reduced the AP-l function. The cytotoxic effect of paeoniflorin was observed in HL-60. These results indicate that paeoniflorin blocks the Fos-Jun heterodimer-binding site of the AP-l DNA and it also has cytotoxic effects on human leukemia cell lines.

• BMB Reports
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• v.43 no.12
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• pp.807-812
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• 2010

$NF{\kappa}B$ and ZAS3 are transcription factors that control important cellular processes including immunity, cell survival and apoptosis. Although both proteins bind the ${\kappa}B$-motif, they produce opposite physiological consequences; $NF{\kappa}B$ activates transcription, promotes cell growth and is often found to be constitutively expressed in cancer cells, while ZAS3 generally represses transcription, inhibits cell proliferation and is downregulated in some cancers. Here, we show that ZAS3 inhibits $NF{\kappa}B$-dependent transcription by competing with $NF{\kappa}B$ for the ${\kappa}B$-motif. Transient transfection studies show that N-terminal 645 amino acids is sufficient to repress transcription activated by $NF{\kappa}B$, and that the identical region also possesses intrinsic repression activity to inhibit basal transcription from a promoter. Finally, in vitro DNA-protein interaction analysis shows that ZAS3 is able to displace $NF{\kappa}B$ by competing with $NF{\kappa}B$ for the ${\kappa}B$-motif. It is conceivable that ZAS3 has therapeutic potential for controlling aberrant activation of $NF{\kappa}B$ in various diseases.

• Journal of Microbiology
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• v.37 no.4
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• pp.229-233
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• 1999

The mitochondrial plasmid pMLP1 from a white-rot fungus, Pleurotus ostreatus, is a double-stranded DNA containing 381 bp terminal inverted repeat (TIR) whose 5'-ends are covalently bound by terminal proteins. The plasmid contains two major open reading frames (ORFs), encoding putative DNA and RNA polymerases, and a minor ORF encoding a small, highly basic protein. To identify the DNA binding activity that recognizes the TIR region of pMLP1, gel retardation assays were performed with mitochondrial extracts. A specific protein binding to a region between 123 and 248 nt within TIR was observed. We examined whether the gene product of mORF1 bindes to this region specifically. E. coli cell extract which contains an overproduced mORF1 protein formed a complex specific to the region between 123 and 248 nt. Inclusion of mORF1 protein in the specific complex formed between P. ostreatus mitochondrial extract and TIR was confirmed by a supershift assay using polyclonal antibodies against the mORF1 protein. Our result suggest that the product of mORF1 may function as a terminal region recognition factor (TRF), recognizing an internal region in TIR.