• BMB Reports
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• v.53 no.5
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• pp.248-253
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• 2020

Gene expression in HIV-1 is regulated by the promoters in 5' long-terminal repeat (LTR) element, which contain multiple DNA regulatory elements that serve as binding sites for cellular transcription factors. YY1 could repress HIV-1 gene expression and latent infection. Here, however, we observed that virus production can be increased by YY1 over-expression and decreased under YY1 depleted condition by siRNA treatment. To identify functional domain(s) of YY1 activation, we constructed a number of YY1 truncated mutants. Our data show that full-length YY1 enhances the viral transcription both through U3 and U3RU5 promoters. Moreover, the C-terminal region (296-414 residues) of YY1 is responsible for the transcriptional upregulation, which could be enhanced further in the presence of the viral Tat protein. The central domain of YY1 (155-295 residues) does not affect LTR activity but has a negative effect on HIV-1 gene expression. Taken together, our study shows that YY1 could act as a transcriptional activator in HIV-1 replication, at least in the early stages of infection.

• Journal of Life Science
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• v.27 no.10
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• pp.1215-1224
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• 2017

Until now, various oncogenic pathways were idenfied. The accumulation of DNA mutation induces genomic instability in the cell, and it makes cancer. The development of bioinformatics and genomics, to find the precise and reliable biomarker is available. This biomarker could be applied the early-dignosis, prediction and convalescence of cancer. Recently, Transposable elements (TEs) have been attracted as the regulator of genes, because they occupy a half of human genome, and the cause of various diseases. TEs induce DNA mutation, as well as the regulation of gene expression, that makes to cancer development. So, we confirmed the relationship between TEs and colon cancer, and provided the clue for colon cancer biomarker. First, we confirmed long interspersed nuclear element-1 (LINE-1), Alu, and long terminal repeats (LTRs) and their relationship to colon cancer. Because these elements have large composition and enormous effect to the human genome. Interestingly, colon cancer specific patterns were detected, such as the hypomethylation of LINE-1, LINE-1 insertion in the APC gene, hypo- or hypermethylation of Alu, and isoform derived from LTR insertion. Moreover, hypomethylation of LINE-1 in proto-oncogene is used as the biomarker of colon cancer metastasis, and MLH1 mutation induced by Alu is detected in familial or hereditary colon cancer. The genes, effected by TEs, were analyzed their expression patterns by in silico analysis. Then, we provided tissue- and gender-specific expression patterns. This information can provide reliable cancer biomarker, and apply to prediction and diagnosis of colon cancer.

• Proceedings of the Korean Society of Life Science Conference
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• 2006.09a
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• pp.63.1-63.1
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• 2006

• Geomechanics and Engineering
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• v.12 no.2
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• pp.257-267
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• 2017

This paper presents laboratory investigation of stabilization of subgrade soil. One type of soil and three types of stabilizers i.e., hydrated lime, class F fly ash and polypropylene fibres are selected in the study. Atterberg limit, compaction, california bearing ratio (CBR), unconfined compressive strength and triaxial shear strength tests are conducted on unstabilized and stabilized soil for varying percentage of stabilizers to analyze the effect of stabilizers on the properties of soil. Vertical compressive strains at the top of unstabilized and stabilized subgrade soil were found out by elasto-plastic finite element analysis using commercial software ANSYS. Strategy for design of optimum pavement section was based on extension in service life (TBR) and reduction in layer thickness (LTR). Extension in service life of stabilized subgrade soil is 6.49, 4.37 and 3.26 times more due to lime, fly ash and fibre stabilization respectively. For a given service life of the pavement, there is considerable reduction in layer thicknesses due to stabilization. It helps in reduction in construction cost of pavement and saving in natural resources as well.

• Journal of Life Science
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• v.29 no.9
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• pp.1047-1054
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• 2019

Transposable elements (TEs) occupy approximately 45% of the human genome and can enter functional genes randomly. During evolutionary radiation, multiple copies of TEs are produced by duplication events. Those elements contribute to biodiversity and phylogenomics. Most of them are controlled by epigenetic regulation, such as methylation or acetylation. Every species contains their own specific mobile elements, and they are divided into DNA transposons and retrotransposons. Retrotransposons can be divided by the presence of a long terminal repeat (LTR). They show various biological functions, such as promoter, enhancer, exonization, rearrangement, and alternative splicing. Also, they are strongly implicated to genomic instability, causing various diseases. Therefore, they could be used as biomarkers for the diagnosis and prognosis of diseases such as cancers. Recently, it was found that TEs could produce miRNAs, which play roles in gene inhibition through mRNA cleavage or translational repression, binding seed regions of target genes. Studies of TE-derived miRNAs offer a potential for the expression of functional genes. Comparative analyses of different types of miRNAs in various species and tissues could be of interest in the fields of evolution and phylogeny. Those events allow us to understand the importance of TEs in relation to biological roles and various diseases.

• Journal of Life Science
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• v.16 no.7 s.80
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• pp.1188-1194
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• 2006

Dementia is a progressive disease of increasing the dysfunction of intellectual and physical ability. In the aging society, many families are suffering from the caring the patients who are diagnosed with dementia. However, dementia is a complex disease affected by the genetic and environmental agents. In the present study, we investigated the transposable elements in relation to dementia. From the analysis of dementia EST (expressed sequence tag) sequences, we found dementia candidate genes, and analyzed expression profiles and repeat elements using bioinformatics tools. This analysis showed that 98 genes were affected in their mRNA sequences by transposable elements expression. Their expressions were affected by the integration of different transposable elements (SINE, LINE, LTR, DNA) during the primate evolution. We believe that our work will be of significant interest to genome scientists, and may help them gain insight into implication of transposable elements expression in dementia.

• Journal of the Korean Society for Aviation and Aeronautics
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• v.9 no.1
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• pp.59-69
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• 2001

The rotor blade is modeled using a composite box beam with arbitrary wall. The active constrained damping layers are bonded to the upper and lower surfaces of the box beam to provide active and passive damping. A finite element model, based on a hybrid displacement theory, is used in the structural analysis. The theory is capable of accurately capturing the transverse shear effects in the composite primary structure, the viscoelastic and the piezoelectric layers within the ACLs. A reduced order model is derived based on the Hankel singular value. A linear quadratic Gaussian (LQG) controller is designed based on the reduced order model and the available measurement output. However, the LQG control system fails to stabilize the perturbed system although it shows good control performance at the nominal operating condition. To improve the robust stability of LQG controller, the loop transfer recovery (LTR) method is applied. Numerical results show that the proposed controller significantly improves rotor aeromechanical stability and suppresses rotor response over large variations in rotating speed by increasing lead-lag modal damping in the coupled rotor-body system.