• Diabetes and Metabolism Journal
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• v.42 no.6
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• pp.465-471
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• 2018

My professional journey to understand the glucose homeostasis began in the 1990s, starting from cloning of the promoter region of glucose transporter type 2 (GLUT2) gene that led us to establish research foundation of my group. When I was a graduate student, I simply thought that hyperglycemia, a typical clinical manifestation of type 2 diabetes mellitus (T2DM), could be caused by a defect in the glucose transport system in the body. Thus, if a molecular mechanism controlling glucose transport system could be understood, treatment of T2DM could be possible. In the early 70s, hyperglycemia was thought to develop primarily due to a defect in the muscle and adipose tissue; thus, muscle/adipose tissue type glucose transporter (GLUT4) became a major research interest in the diabetology. However, glucose utilization occurs not only in muscle/adipose tissue but also in liver and brain. Thus, I was interested in the hepatic glucose transport system, where glucose storage and release are the most actively occurring.

• Tuberculosis and Respiratory Diseases
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• v.56 no.5
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• pp.465-484
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• 2004

Background : Insulin-like growth factor (IGF)-binding protein-3 (IGFBP-3) inhibits the proliferation of non-small cell lung cancer (NSCLC) cells by inducing apoptosis. Methods : In this study, we investigated whether hypermethylation of IGFBP-3 promoter play an important role in the loss of IGFBP-3 expression in NSCLC. We also studied the mechanisms that mediate the silencing of IGFBP-3 expression in the cell lines which have hypermethylated IGFBP-3 promoter. Results : The IGFBP-3 promoter has hypermethylation in 7 of 15 (46.7%) NSCLC cell lines and 16 (69.7%) of 23, 7 (77.8%) of 9, 4 (80%) of 5, 4 (66.7 %) of 6, and 6 (100%) of 6 tumor specimens from patients with stage I, II, IIIA, IIIB, and IV NSCLC, respectively. The methylation status correlated with the level of protein and mRNA in NSCLC cell lines. Expression of IGFBP-3 was restored by the demethylating agent 5'-aza-2'-deoxycytidine (5'-aza-dC) in a subset of NSCLC cell lines. The Sp-1/ Sp-3 binding element in the IGFBP-3 promoter, important for promoter activity, was methylated in the NSCLC cell lines which have reduced IGFBP-3 expression and the methylation of this element suppressed the binding of the Sp-1 transcription factor. A ChIP assay showed that the methylation status of the IGFBP-3 promoter influenced the binding of Sp-1, methyl-CpG binding protein-2 (MeCP2), and histone deacetylase (HDAC) to Sp-1/Sp-3 binding element, which were reversed by by 5'-aza-dC. In vitro methylation of the IGFBP-3 promoter containing the Sp-1/Sp-3 binding element significantly reduced promoter activity, which was further suppressed by the overexpression of MeCP2. This reduction in activity was rescued by 5'-aza-dC. Conclusion : These findings indicate that hypermethylation of the IGFBP-3 promoter is one mechanism by which IGFBP-3 expression is silenced and MeCP2, with recruitment of HDAC, may play a role in silencing of IGFBP-3 expression. The frequency of this abnormality is also associated with advanced stages among the patients with NSCLC, suggesting that IGFBP-3 plays an important role in lung carcinogenesis/progression and that the promoter methylation status of IGFBP-3 may be a marker for early molecular detection and/or for monitoring chemoprevention efforts.

• Journal of Life Science
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• v.18 no.4
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• pp.461-466
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• 2008

Transforming growth $factor-{\beta}$ ($TGF-{\beta}$)-dependent apoptosis is important in the elimination of damaged or abnormal cells from normal tissues in vivo. Gadd45b has been known to participate in $TGF-{\beta}-induced$ apoptosis by the activation of p38 kinase. In this report, we show that Gadd45b is an immediate-early response gene for $TGF-{\beta}$ during apoptosis in EpH4 cells. To elucidate the molecular mechanism of $TGF-{\beta}-induced$ Gadd45b gene expression, we cloned the 5'-flanking region of the mouse Gadd45b gene. When transfected into EpH4 cells, this 5'-flanking region conferred promoter activity and inducibility by $TGF-{\beta}$. Deletion analyses demonstrated that the minimal promoter activity was detected in the proximal region 220 bp upstream of the transcription initiation site. We also found that the proximal Gadd45b promoter is activated by $TGF-{\beta}$ through the action of Smad2, Smad3, and Smad4. Finally, we show that the expression of Gadd45b gene by $TGF-{\beta}$ is suppressed in EpRas cells in which $TGF-{\beta}$ could not induce apoptosis, suggesting that Gadd45b may be a crucial target for $TGF-{\beta}-induced$ apoptosis in EpH4 cells.

• Journal of Sericultural and Entomological Science
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• v.50 no.2
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• pp.122-125
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• 2012

This study was aimed for a development of a useful gene promoter which has a transcript expressional specificity in the early embryonic period of the silkworm, Bombyx mori. To select a useful gene expressed in the early embryonic stage, we constructed and analyzed a PCR-base subtraction cDNA library. In subtractive hybridization analysis, we confirmed four clones as differently expressed genes(BmNanos-like, BmNanos-P, BmNanos-O, BmVasa mRNAs). Northern hybridization and real time PCR results reveled that the BmNanos-like gene promoter is suitable for the silkworm transgenic vector system. Further defined studies on molecular functions and biological roles of their promoters will give us well-fined information and its application.

• Molecules and Cells
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• v.23 no.1
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• pp.80-87
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• 2007

Beet curly top virus (BCTV) and Beet severe curly top virus (BSCTV), members of curtoviruses, encode seven open reading frames (ORFs) within a ~3 kb genome. One of these viral ORFs, C1, is known to play an important role in the early stage of viral infection in plants during initiation of viral DNA replication. We used promoter:: reporter (${\beta}$-glucuronidase) gene fusions in transgenic Arabidopsis to identify the putative promoter region of BCTV ORF C1. Unlike other geminiviruses, the intergenic region of BCTV was not sufficient to promote C1 expression in transgenic plants. When sequences extending into the coding region of C1 were tested, strong expression of the reporter protein was observed in vascular tissues of transgenic plants. This expression was not dependent on the presence of the intergenic regions or proximal 5' portions of the C1 coding region. Transgenic plants expressing a reporter gene under control of the putative complete C1 promoter were inoculated with virus to determine if any viral transcript affected C1 expression. Virus inoculated plants did not show any altered pattern or change in of reporter gene expression level. These results suggest that (1) important transcriptional activator elements for C1 expression reside in the 3' portion of C1 coding area itself, (2) C1 protein does not auto-regulate its own expression and (3) C1 expression of two curtoviruses is controlled differently compared to other geminiviruses.

• Asian-Australasian Journal of Animal Sciences
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• v.20 no.5
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• pp.784-788
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• 2007

Growth hormone-releasing hormone (GHRH), a hypothalamic neuropeptide can stimulate the growth hormone secretion from the anterior pituitary. In this study, a porcine GHRH expression plasmid pHC-GHRH was used to enhance growth performance through ectopic expressions in muscle tissues of rats. Rats injected with the plasmid of pHC-GHRH and pCMV-GHRH exhibited cumulative weight gains 6.4% and 1% greater than controls. During a 5-day period, significant weight gain differences were observed as follows compared with that of control: during 5-10 days post-injection (DPI) period, the group pHC-GHRH on average 14.5% heavier than controls, $40.73{\pm}0.88$ g vs. $35.57{\pm}1.23$ g (p = 0.0023); during 10-15 DPI period, the group pHC-GHRH on average 13.6% heavier than controls, $37.49{\pm}2.85$ g vs. $33.00{\pm}1.56$ g (p = 0.0146); during 15-20 DPI period, the group pHC-GHRH on average 17.8% heavier than controls, $25.64{\pm}1.39$ g vs. $21.77{\pm}1.27$ g (p<0.05). In addition, plasmids-treated rats maintained higher serum IGF-I than controls. Significant differences of IGF-I were observed on 13 DPI and on 40 DPI in pHC-GHRH group compared with that of controls. This was accomplished through the use of an improved expression cassette that included the cytomegalovirus (CMV) immediate early enhancer/promoter in combination with a 1.5-kilobase portion of porcine ${\alpha}$-skeletal muscle actin promoter.

• Microbiology and Biotechnology Letters
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• v.29 no.1
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• pp.18-24
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• 2001

Expression of the baculovirus major envelope glycoprotein gene(gp64) is regulated by transcription from botha early and late promoters. To develop a transient expression vector under the control of gp64 gene promoter, the gp64 gene of Bombyx mori nucleopolyhedrovirus-K1(BmNPV-K1) was characterized. The gp64 gene was local-ized at EcoR I-Pst I 7.38-kb fragment of the BmNPV-K1 genome. The EcorR 1-Pst I 7.38-kb fragment was cloned and the nucleotide sequence of 2,277 bases including the coding region of gp64 gene was determined. Based on these results, transient expression vector using gp64 gene promoter was constructed and named as pBm64. E.coli lacZ gene was introduced onto pBm64 as a reporter gene and expressed transiently in B. mori 5(Bm 5) cells. The expression vector transfected into the cells was maintained stably for 1 to 5 days. In order to confirm the expression of the reporter gene by gp64 promoter, recombinant virus was constructed. The recombinant virus has two independent transcription units in opposite orientations with two promoters; gp64 and polyhedrin gene promoters each initiating transcription of $\beta$-galactosidase and polyhedrin, respectively. Polyhedra formation and expression of $\beta$-galactosidase in Bm5 cells infected with the recombinant virus were observed with phase contrast microscope and in situ staining.

• BMB Reports
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• v.53 no.6
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• pp.323-328
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• 2020

Matrix metalloproteinase 1 (MMP-1), a calcium-dependent zinccontaining collagenase, is involved in the initial degradation of native fibrillar collagen. Tissue necrosis factor-alpha (TNFα) is a pro-inflammatory cytokine that is rapidly produced by dermal fibroblasts, monocytes/macrophages, and keratinocytes and regulates inflammation and damaged-tissue remodeling. MMP-1 is induced by TNFα and plays a critical role in tissue remodeling and skin aging processes. However, the regulation of the MMP1 gene by TNFα is not fully understood. We aimed to find additional cis-acting elements involved in the regulation of TNFα-induced MMP1 gene transcription in addition to the nuclear factor-kappa B (NF-κB) and activator protein 1 (AP1) sites. Assessments of the 5'-regulatory region of the MMP1 gene, using a series of deletion constructs, revealed the requirement of the early growth response protein 1 (EGR-1)-binding sequence (EBS) in the proximal region for proper transcription by TNFα. Ectopic expression of EGR-1, a zinc-finger transcription factor that binds to G-C rich sequences, stimulated MMP1 promoter activity. The silencing of EGR-1 by RNA interference reduced TNFα-induced MMP-1 expression. EGR-1 directly binds to the proximal region and transactivates the MMP1 gene promoter. Mutation of the EBS within the MMP1 promoter abolished EGR-1-mediated MMP-1 promoter activation. These data suggest that EGR-1 is required for TNFα-induced MMP1 transcriptional activation. In addition, we found that all three MAPKs, ERK1/2, JNK, and p38 kinase, mediate TNFα-induced MMP-1 expression via EGR-1 upregulation. These results suggest that EGR-1 may represent a good target for the development of pharmaceutical agents to reduce inflammation-induced MMP-1 expression.

• Proceedings of the PSK Conference
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• 2004.10a
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• pp.147.2-148
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• 2004

• The Plant Pathology Journal
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• v.20 no.1
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• pp.18-21
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• 2004

The root hair provides a major entering spot for the symbiotic legume rhizobia. It is obvious that dynamic cell wall modification occurs in the plant root hair during the early microbe invasion. Expansins are nondestructive cell wall-modifying proteins that are involved in cell growth and differentiation. Among about 40 expansin genes in Arabidopsis, two expansin genes are expressed specifically in the root hair cell. Orthologous genes of this Arabidopsis root hair expansins have been found in other Brassica members, rice, and Medicago truncatula (a legume). In this review, I discuss the probable function of expansins during the early symbiotic process between the root hair and microbes and the regulation of root hair expansin genes in a comparative approach.