• Development and Reproduction
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• v.5 no.1
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• pp.81-88
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• 2001

Gonadotropin-releasing hormone (GnRH) has been known to play a role in the regulation of hCG secretion by human placenta. Recently, a gene encoding the second f개m of GnRH (GnRH-II) was identified in human. Herein, we demonstrate that GnRH-II is expressed in human placenta and assess GnRH-II expression by nested RT-PCR and immunohistochemistry in human placenta during the first trimester. We found that two altematively spliced transcripts of GnW-II mRNA were expressed in human placental tissues of first trimester and the shorter variant had a 21-bp deletion in GnRH-associated peptide (GAP). Immunoreactive GnRH-II was localized in both cytotrophoblastic and syncytiotrophoblastic cytoplasm. The immunostaining intensity was stronger in cytotrophoblast. Villous stromal cells also showed GnRH-II immunoreactiyiry. The results of our study report that the second isoform of GnRH (GnRH-II) is expressed in the first trimester human placenta and we suggest that GnRH-II may also play a regulatory role in maintenance of early pregnancy and hCG secretion in human placenta.

• Journal of Life Science
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• v.26 no.1
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• pp.140-145
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• 2016

Genes in multicellular organisms are transcribed in development, differentiation, or tissue-specific manners. The transcription of genes is activated by enhancers, which are transcription regulatory elements located at long distances from the genes. Recent studies have reported that noncoding RNAs are transcribed from active enhancers by RNA polymerase II (RNA Pol II); these are called enhancer RNAs (eRNAs). eRNAs are transcribed bi-directionally from the enhancer core, and are capped on the 5’ end but not spliced or polyadenylated on the 3’ end. The transcription of eRNAs requires the binding of transcription activators on the enhancer and associates positively with the transcription of the target gene. The transcriptional inhibition of eRNAs or the removal of eRNA transcripts results in the transcriptional repression of the coding gene. The transcriptional procedure of eRNAs causes enhancer- specific histone modifications, such as histone H3K4me1/2. eRNA transcripts directly interact with Mediator and Rad21, a cohesin subunit, generating a chromatin loop structure between the enhancer and the promoter of the target gene. The recruitment of RNA Pol II into the promoter and its elongation through the coding region are facilitated by eRNAs. Here, we will review the features of eRNAs, and discuss the mechanism of eRNA transcription and the roles of eRNAs in the transcriptional activation of target genes.

• Journal of the Korea institute for structural maintenance and inspection
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• v.21 no.6
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• pp.196-205
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• 2017

In precast deck system, structural performance and serviceability are mostly determined by the connection methods between the precast decks. This study proposes precast deck system with asymmetric ribbed connection details using High Strength Fiber Reinforced Concrete(HSFRC) with filler. To verify the proposed method, the flexural performance experiment was carried out with variation of joint cross section type and splice rebar details. From the test results, regardless of joint details, spliced tensile rebars of specimens were deformed to yielding strain level. Also, all types of specimens resulted in sufficient flexural performance. These test results show that the minimum lap splice length specified in current Korea Highway Bridge Design Code is conservative for precast deck joint using HSFRC. Therefore, splice details can be simplified and joint width can be reduced by using HSFRC with filler between the precast decks, and the proposed precast deck systems can be applied to the connection part of precast decks effectively.

• Journal of Life Science
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• v.28 no.10
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• pp.1233-1243
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• 2018

Sterol regulatory-element binding proteins (SREBPs) are a family of transcription factors that regulate lipid homeostasis and metabolism by controlling the expression of enzymes required for endogenous cholesterol, fatty acid (FA), triacylglycerol, and phospholipid synthesis. The three SREBPs are encoded by two different genes. The SREBP1 gene gives rise to SREBP-1a and SREBP-1c, which are derived from utilization of alternate promoters that yield transcripts in which distinct first exons are spliced to a common second exon. SREBP-2 is derived from a separate gene. Additionally, SREBPs are implicated in numerous pathogenic processes, such as endoplasmic reticulum stress, inflammation, autophagy, and apoptosis. They also contribute to obesity, dyslipidemia, diabetes mellitus, and nonalcoholic fatty liver diseases. Genome-wide analyses have revealed that these versatile transcription factors act as important nodes of biological signaling networks. Changes in cell metabolism and growth are reciprocally linked through SREBPs. Anabolic and growth signaling pathways branch off and connect to multiple steps of SREBP activation and form complex regulatory networks. SREBPs are activated through the PI3K-Akt-mTOR pathway in these processes, but the molecular mechanism remains to be understood. This review aims to provide a comprehensive understanding of the role of SREBPs in physiology and pathophysiology at the cell, organ, and organism levels.

• Journal of the Earthquake Engineering Society of Korea
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• v.8 no.3
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• pp.1-12
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• 2004

Due to the 1989 Loma Prieta, 1995 Hyogoken Nambu earthquakes, etc, a number of bridge columns  were collapsed in flexure-shear failures as a consequence of the premature termination of the column longitudinal reinforcement. Nevertheless, previous researches for the performance of bridge columns were concentrated on the flexural failure mode. It is well understood that the seismic behaviour of RC bridge piers was dependent on the performance of the plastic hinge of RC bridge piers, the ductility of which was desirable to be computed on the basis of the curvature. Experimental investigation was made to evaluate the variation of the curvature of the plastic hinge  region for the seismic performance of earthquake-damaged RC columns in flexure-shear failure mode. Seven test specimens in the aspect ratio of 2.5 were made with test parameters: confinement ratios, lap splices, and retrofitting FRP materials. They were damaged under series of artificial earthquakes that could be compatible in Korean peninsula. Directly after the pseudo-dynamic test, damaged columns were retested under inelastic reversal cyclic loading under a constant axial load, $P=0.1f_{ck}A_g$. Residual seismic capacity of damaged specimens was evaluated by analzying the moment-curvature hysteresis and the curvature ductility. Test results show that the biggest curvature was developed around 15cm above the footing, which induced the column failure. It was observed that RC bridge specimens with lap-spliced longitudinal steels appeared to fail at low curvature ductility but significant improvement was made in the curvature ductility of RC specimens with FRP straps wrapped around the plastic hinge region. Based on the experimental variation of the curvature of RC specimens, new equivalent length of the plastic hinge region was proposed by considering the lateral confinement in this study. The analytical and experimental relationship between the displacement and the curvature ductility were compared based on this proposal, which gave excellent result.

• Journal of Embryo Transfer
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• v.32 no.1
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• pp.25-31
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• 2017

This study was conducted to investigate the effect of activation method on the endoplasmic reticulum (ER) stress induction, apoptosis and in vitro development of porcine parthenogenetic embryos. Porcine in vitro matured oocytes were activated by four activation methods; 1) electric stimulus (ES) (E), 2) $ES+10{\mu}M$ Ca-ionophore (A23187) treatment (EC), 3) ES+2 mM 6-dimethylaminopurine (6-DMAP) treatment (ED), or 4) ES+A23187 and 6-DMAP treatments (ECD). Parthenogenetic embryos were sampled to analyze x-box binding protein 1 (Xbp1) mRNA, ER stress-associated genes and apoptosis genes at 3 h after ES and the 1-cell and blastocyst stages. In the EC group, the band intensity of spliced Xbp1 (Xbp1s) mRNA was higher than those of the other groups at the 3 h and 1-cell stage, and higher than that of the E group at the blastocyst stage. Four ER stress-associated genes were expressed at the highest level in the EC group and weakly expressed in the ED group at 3 h after activation. However, most of the genes were highly expressed at the 1-cell and blastocyst stages with some variation in the EC and ECD groups. Expression of Bcl-2-associated X protein (Bax) and caspase-3 mRNA was significantly higher in the EC group than in the other groups at all development stages. The developmental rates to the blastocyst stage were higher in the ED and ECD groups than in the E and EC groups. These results suggest that the intracellular ER stress of parthenogenetic porcine embryos is affected by the activation method and subsequently lead to the apoptosis of embryos.

• Journal of the Society of Disaster Information
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• v.20 no.2
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• pp.329-338
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• 2024

Purpose: This study verified the safety of the improved box-type girder behavior by comparing and evaluating the bending behavior results of a full-scale specimen based on the analytical behavior of the splice element PSC U-shaped girder with integrated tensioning systems. Method: Based on the results of the service and strength limit state design using the bridge design standard(limit state design method), the applied load of a 40m full-scale specimen was calculated and a static loading experiment using the four-point loading method was performed. Result: When the design load, crack load, and ultimate load were applied, the specimen deflection occurred at 97.1%, 98.5%, and 79.0% of the analytical deflection value. When the design load, crack load, and ultimate load were applied, the crack gauge was measured at 0.009~0.035mm, 0.014~0.050mm, and 6.383~5.522mm at each connection. Conclusion: The specimen behaved linear-elastically until the crack load was applied, and after cracks occurred, it showed strainhardening up to the ultimate load, and it was confirmed that the resistance of bending behavior was clearly displayed against the applied load. The cracks in the dry joints were less than 25% of grade B based on the evaluation of facility condition standard. The final residual deformation after removing the ultimate load was 0.114mm, confirming the stable behavior of the segment connection.

• Reproductive and Developmental Biology
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• v.35 no.1
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• pp.33-45
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• 2011

Heat shock protein 90 (Hsp90) is ATPase-directed molecular chaperon and affects survival of cancer cell. Inhibitory effect of Hsp90 by inducing cell cycle arrest and apoptosis in the cancer cell was reported. However, its role during oocyte maturation and early embryo development is very insufficient. In this study, we traced the effects of Hsp90 inhibitor, 17-allylamino-17-demethoxygeldanamycin (17-AAG), on meiotic maturation and early embryonic development in pigs. We also investigated several indicators of developmental potential, including structural integrity, gene expression (Hsp90-, cell cycle-, and apoptosis-related genes), and apoptosis, which are affected by 17-AAG. Then, we examined the roles of Hsp90 inhibitor on viability of primary cells in pigs. Porcine oocytes were cultured in the NCSU-23 medium with or without 17-AAG for 44 h. The proportion of GV arrested oocytes was significantly different between the 17-AAG treated and untreated group (78.2 vs 34.8%, p<0.05). After completion of meiotic maturation, the proportion of MII oocytes was lower in the 17-AAG treated group than in the control group (27.9 vs 71.0%, p<0.05). After IVF, the percentage of penetrated oocytes was significantly lower in the 17-AAG treated group (25.2%), resulting in lower normal pronucleus formation (2PN of 14.6%). Therefore, the inhibition of meiotic progression by Hsp90 inhibitor played a critical role in fertilization status. Porcine embryo were cultured in the PZM-3 medium with or without 17-AAG for 6 days. In result, significant differences in developmental potential were detected between the embryos that were cultured with or without 17-AAG. Terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL) showed that the number of containing fragmented DNA at the blastocyst stage increased in the 17-AAG treated group compared with control (7.5 vs 4.4, respectively). Blastocysts that developed in the 17-AAG treated group had low structural integrity and high apoptotic nuclei than those of the untreated control, resulting in decrease the embryonic qualities of preimplantation porcine blastocysts. The mRNA expressions of cell cycle-related genes were down-regulated in the 17-AAG treated group compared with control. Also, the expression of the pro-apoptotic gene Bax increased in 17-AAG treated group, whereas expression of the anti-apoptotic gene Bel-XL decreased. However, the expression of ER stress-related genes did not changed by 17-AAG. Cultured pESF cells were treated with or without 17-AAG and used for MIT assay. The results showed that viability of pESF cells were decreased by treatment of 17-AAG ($2{\mu}M$) for 24 hr. These results indicated that 17-AAG decreased cell proliferation and increased cell death. Expression patterns Hsp90 complex genes (Hsp70 and p23), cell cycle-related genes (cdc2 and cdc25c) and apoptosis-related genes (Bax and Bcl-XL) were significantly changed by using RT-PCR analysis. The spliced form of pXbp-1 product (pXbp-1s) was detected in the tunicamycin (TM) treated cells, but it is not detected in 17-AAG treated cells. In conclusion, Hsp90 appears to play a direct role in porcine early embryo developmental competence including structural integrity of blastocysts. Also, these results indicate that Hsp90 is closely associated with cell cycle- and apoptosis-related genes expression in developing porcine embryos.

• Journal of Life Science
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• v.34 no.2
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• pp.113-121
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• 2024

Endoplasmic reticulum (ER) stress responses are markedly induced during toxic responses caused by various chemical substances, including difenoconazole, but no research has been conducted on 1,2,3-trichloropropane (TCP), a chemical that is generally used in agriculture and industry, which induces hepatotoxicity. Therefore, in this study, the changes in indicators for hepatotoxicity, apoptosis, and ER stress were analyzed in TCP-treated Sprague Dawley (SD) rats to study the regulatory mechanism of ER stress during the hepatotoxicity. The TCP-treated group decreased in body weight and dietary intake compared to the vehicle-treated group, and necrosis and vacuolation increased significantly in liver histology. In addition, the expression of apoptosis-related factors, including Bax/Bcl-2 and cleaved caspase (Cas)-3/Cas-3 increased significantly in the TCP-treated group compared to the vehicle-treated group. In the analysis of ER stress response indicators, the expression of C/EBP homologous protein (CHOP), phospho-eukaryotic translation initiation factor 2 alpha subunit (eIF2α), and phospho-inositol-requiring enzyme 1α (IRE1α) increased only in the TCP100-treated group and decreased in the TCP200-treated group. However, the transcriptions of growth arrest and DNA damage-34 (GADD34) increased in the TCP200-treated group, while Spliced X-box binding protein-1 (XBP1s) and unspliced XBP1(XBP1u) decreased in the same group. These results suggest that the ER stress response is successfully triggered during the hepatotoxicity induced by TCP treatment through the alternative regulation of the unfolded-protein response (UPR) pathway.