• BMB Reports
• /
• 제39권5호
• /
• pp.595-606
• /
• 2006

Metallothioneins are a group of low molecular mass and cysteine-rich metal-binding proteins, ubiquitously found in most living organisms. They play an important role in maintaining intracellular metal homeostasis, eliminating metal toxification and protecting against intracellular oxidative damages. Analysis of complete rice genome sequences revealed eleven genes encoding putative metallothionein (OsMT), indicating that OsMTs constitute a small gene family in rice. Expression profiling revealed that each member of the OsMT gene family differs not only in sequence but also in their tissue expression patterns, suggesting that these isoforms may have different functions they perform in specific tissues. On the basis of OsMT structural and phylogenetic analysis, the OsMT family was classified as two classes and class I was subdivided into four types. Additionally, in this paper we also present a complete overview of this family, describing the gene structure, genome localization, upstream regulatory element, and exon/intron organization of each member in order to provide valuable insight into this OsMT gene family.

• 한국수정란이식학회:학술대회논문집
• /
• 한국수정란이식학회 2002년도 국제심포지엄
• /
• pp.71-71
• /
• 2002

Promoters for milk proteins have been used far producing transgenic animals due to their temporal and spatial expression patterns. ${\beta}$-casein, a calcium-sensitive casein, is a major milk protein that corresponds ca. 30 per cent of total milk protein. Expression of ${\beta}$-casein is controlled by lactogenic hormones such as prolactin (PRL), composite response elements (CoREs) and transcription factors. CoREs are clusters of transcription factor binding sites containing both positive and negative regulatory elements. ${\beta}$-casein gene promoter contains various regions (CoREs) for gene transcription. We analyzed the promoter region by mutagenesis using exonuclease III and linker-scanning. Transcription control elements usually are positioned in 5'-flanking region of the gene. However, in some cases, these elements are located in other regions such as intron 1. The nucleotide sequences of ${\beta}$-casein promote. region has been reported (E12614). However, the properties of the promoter is not yet clear. In this study, we plan to investigate the properties of cis-regulating elements of porcine ${\beta}$-casein by mutation analysis and expression analysis using dual-luciferase repoter assay system.

• BMB Reports
• /
• 제29권4호
• /
• pp.386-392
• /
• 1996

A Saccharomyces cerevisiae Protein Tyrosine Phosphatase, PTP1, was expressed from an Escherichia coli expression system and milligram quantities of active PTP1 were purified chromatographically. The substrate specificity of the recombinant PTP1 was probed using synthetic phosphotyrosine-containing peptides corresponding to the regulatory phosphorylation sites of the yeast MAP kinase homologues $Fus3_{176-186}$, $Kss1_{179-189}$, and $Hog1_{170-180}$. Peptide sequences derived from the MAP kinase homologues were chosen arbitrarily as starting points for sequence variation studies even though they are not likely to be candidates for physiological substrates of PTP1. Phosphotyrosyl-$Hog1_{170-180}$ peptide showed a $K_M$ value of 877 ${\mu}M$ and phosphorylated $Kss1_{179-189}$ and $Fus3_{176-186}$ peptides showed lower $K_M$ values of 74 ${\mu}M$ and 51 ${\mu}M$ each. To study the effect of sequence variations of the peptide, amino acids of the undecapeptide $Hog1_{170-180}$ (DPQMTGpYVSTR) were sequentially substituted by an alanine residue. More extensive variations of each amino acid revealed positional importance of each amino acid residue. Based on these results, we derived a peptide sequence (DADEpYDA) that is recognized by PTP1 with an affinity ($K_M$ is 4 ${\mu}M$) significantly higher than that of the peptides derived from the phosphorylation sites of Fus3, Kss1, and Hog1.

• Molecules and Cells
• /
• 제22권2호
• /
• pp.182-188
• /
• 2006

Dlx5 and Osx are master regulatory proteins essential for initiating the cascade leading to osteoblast differentiation in mammals, but the mechanism of osteoblast-specific expression is not fully understood. DNA methylation at CpG sequences is involved in tissue and cell type-specific gene expression. We investigated the methylation status of Dlx5 and Osx in osteogenic and nonosteogenic cell lines by methylationspecific PCR (MSP). The CpG dinucleotides of the Dlx5 and Osx promoter regions were unmethylated in osteogenic cell lines transcribing these genes but methylated in nonosteogenic cell lines. Treatment of C2C12 cells with 5-AzadC induced dose- and timedependent expression of Dlx5 and Osx mRNA by demethylating the corresponding promoters. Furthermore the mRNAs for the osteoblast markers ALP and OC, which were undetectable in untreated cells, gradually increased after 5-AzadC treatment. In addition, BMP-2 stimulation induced Dlx5 expression by hypomethylating its promoter. These findings suggest that DNA methylation plays an important role in cell type-specific expression of Dlx5 and Osx.

• Nuclear Engineering and Technology
• /
• 제46권6호
• /
• pp.803-816
• /
• 2014

Defense-in-depth is a fundamental safety principle for the design and operation of nuclear power plants. Despite its general appeal, defense-in-depth is not without its drawbacks, which include its potential for concealing the occurrence of hazardous states in a system, and more generally rendering the latter more opaque for its operators and managers, thus resulting in safety blind spots. This in turn translates into a shrinking of the time window available for operators to identify an unfolding hazardous condition or situation and intervene to abate it. To prevent this drawback from materializing, we propose in this work a novel safety principle termed "observability-in-depth". We characterize it as the set of provisions technical, operational, and organizational designed to enable the monitoring and identification of emerging hazardous conditions and accident pathogens in real-time and over different time-scales. Observability-in-depth also requires the monitoring of conditions of all safety barriers that implement defense-in-depth; and in so doing it supports sensemaking of identified hazardous conditions, and the understanding of potential accident sequences that might follow (how they can propagate). Observability-in-depth is thus an information-centric principle, and its importance in accident prevention is in the value of the information it provides and actions or safety interventions it spurs. We examine several "event reports" from the U.S. Nuclear Regulatory Commission database, which illustrate specific instances of violation of the observability-in-depth safety principle and the consequences that followed (e.g., unmonitored releases and loss of containments). We also revisit the Three Mile Island accident in light of the proposed principle, and identify causes and consequences of the lack of observability-in-depth related to this accident sequence. We illustrate both the benefits of adopting the observability-in-depth safety principle and the adverse consequences when this principle is violated or not implemented. This work constitutes a first step in the development of the observability-in-depth safety principle, and we hope this effort invites other researchers and safety professionals to further explore and develop this principle and its implementation.

• Molecules and Cells
• /
• 제37권11호
• /
• pp.795-803
• /
• 2014

To withstand ever-changing environmental stresses, plants are equipped with phytohormone-mediated stress resistance mechanisms. Salt stress triggers abscisic acid (ABA) signaling, which enhances stress tolerance at the expense of growth. ABA is thought to inhibit the action of growth-promoting hormones, including brassinosteroids (BRs). However, the regulatory mechanisms that coordinate ABA and BR activity remain to be discovered. We noticed that ABA-treated seedlings exhibited small, round leaves and short roots, a phenotype that is characteristic of the BR signaling mutant, brassinosteroid insensitive1-9 (bri1-9). To identify genes that are antagonistically regulated by ABA and BRs, we examined published Arabidopsis microarray data sets. Of the list of genes identified, those upregulated by ABA but downregulated by BRs were enriched with a BRRE motif in their promoter sequences. After validating the microarray data using quantitative RT-PCR, we focused on RD26, which is induced by salt stress. Histochemical analysis of transgenic Arabidopsis plants expressing RD26pro:GUS revealed that the induction of GUS expression after NaCl treatment was suppressed by co-treatment with BRs, but enhanced by co-treatment with propiconazole, a BR biosynthetic inhibitor. Similarly, treatment with bikinin, an inhibitor of BIN2 kinase, not only inhibited RD26 expression, but also reduced the survival rate of the plant following exposure to salt stress. Our results suggest that ABA and BRs act antagonistically on their target genes at or after the BIN2 step in BR signaling pathways, and suggest a mechanism by which plants fine-tune their growth, particularly when stress responses and growth compete for resources.

• Molecules and Cells
• /
• 제38권8호
• /
• pp.705-714
• /
• 2015

We investigated the role of HDAC3 in anti-cancer drug-resistance. The expression of HDAC3 was decreased in cancer cell lines resistant to anti-cancer drugs such as celastrol and taxol. HDAC3 conferred sensitivity to these anti-cancer drugs. HDAC3 activity was necessary for conferring sensitivity to these anti-cancer drugs. The down-regulation of HDAC3 increased the expression of MDR1 and conferred resistance to anti-cancer drugs. The expression of tubulin ${\beta}3$ was increased in drug-resistant cancer cell lines. ChIP assays showed the binding of HDAC3 to the promoter sequences of tubulin ${\beta}3$ and HDAC6. HDAC6 showed an interaction with tubulin ${\beta}3$. HDAC3 had a negative regulatory role in the expression of tubulin ${\beta}3$ and HDAC6. The down-regulation of HDAC6 decreased the expression of MDR1 and tubulin ${\beta}3$, but did not affect HDAC3 expression. The down-regulation of HDAC6 conferred sensitivity to taxol. The down-regulation of tubulin ${\beta}3$ did not affect the expression of HDAC6 or MDR1. The down-regulation of tubulin ${\beta}3$ conferred sensitivity to anti-cancer drugs. Our results showed that tubulin ${\beta}3$ serves as a downstream target of HDAC3 and mediates resistance to microtubule-targeting drugs. Thus, the HDAC3-HDAC6-Tubulin ${\beta}$ axis can be employed for the development of anti-cancer drugs.

• BMB Reports
• /
• 제52권11호
• /
• pp.653-658
• /
• 2019

MYB-type transcription factors (TFs) play important roles in plant growth and development, and in the rapid responses to unfavorable environmental conditions. We recently reported the isolation and characterization of a rice (Oryza sativa) MYB TF, OsMYB102, which is involved in the regulation of leaf senescence by downregulating abscisic acid (ABA) biosynthesis and the downstream signaling response. Based on the similarities of their sequences and expression patterns, OsMYB102 appears to be a homolog of the Arabidopsis thaliana AtMYB44 TF. Since AtMYB44 is a key regulator of leaf senescence and abiotic stress responses, it is important to examine whether AtMYB44 homologs in other plants also act similarly. Here, we generated transgenic Arabidopsis plants expressing OsMYB102 (OsMYB102-OX). The OsMYB102-OX plants showed a delayed senescence phenotype during dark incubation and were more susceptible to salt and drought stresses, considerably similar to Arabidopsis plants overexpressing AtMYB44. Real-time quantitative PCR (RT-qPCR) revealed that, in addition to known senescence-associated genes, genes encoding the ABA catabolic enzymes AtCYP707A3 and AtCYP707A4 were also significantly upregulated in OsMYB102-OX, leading to a significant decrease in ABA accumulation. Furthermore, protoplast transient expression and chromatin immunoprecipitation assays revealed that OsMYB102 directly activated AtCYP707A3 expression. Based on our findings, it is probable that the regulatory functions of AtMYB44 homologs in plants are highly conserved and they have vital roles in leaf senescence and the abiotic stress responses.

• Nuclear Engineering and Technology
• /
• 제53권10호
• /
• pp.3236-3246
• /
• 2021

Lessons learned from the Fukushima Daiichi nuclear power plant accident directed that multiple failures should be considered more seriously rather than single failure in the licensing bases and safety cases because attempts to take accident management measures could be unsuccessful under the high radiation environment aggravated by multiple failures, such as complete loss of electric power, uncontrollable loss of coolant inventory, failure of essential safety function recovery. In the case of the complete loss of electric power called station blackout (SBO), if there is no mitigation action for recovering safety functions, the reactor core would be overheated, and severe fuel damage could be anticipated due to the failure of the active heat sink. In such a transient condition at CANDU-6 plants, the seal failure of the primary heat transport (PHT) pumps can facilitate a consequent increase in the fuel sheath temperature and eventually lead to degradation of the fuel integrity. Therefore, it is necessary to specify the regulatory guidelines for multiple failures on a licensing basis so that licensees should prepare the accident management measures to prevent or mitigate accident conditions. In order to explore the efficiency of implementing accident management strategies for CANDU-6 plants, this study proposed a realistic accident analysis approach on the SBO transient with multiple-failure sequences such as seal failure of PHT pumps without operator's recovery actions. In this regard, a comparative study for two PHT pump seal failure modes with and without coolant seal leakage was conducted using a best-estimate code to precisely investigate the behaviors of thermal-hydraulic parameters during transient conditions. Moreover, a sensitivity analysis for different PHT pump seal leakage rates was also carried out to examine the effect of leakage rate on the system responses. This study is expected to provide the technical bases to the accident management strategy for unmitigated transient conditions with multiple failures.

• Genomics & Informatics
• /
• 제19권4호
• /
• pp.47.1-47.12
• /
• 2021

Kaposi's sarcoma-associated herpesvirus (KSHV) is one of the few human oncogenic viruses, which causes a variety of malignancies, including Kaposi's sarcoma, multicentric Castleman disease, and primary effusion lymphoma, particularly in human immunodeficiency virus patients. The currently available treatment options cannot always prevent the invasion and dissemination of this virus. In recent times, siRNA-based therapeutics are gaining prominence over conventional medications as siRNA can be designed to target almost any gene of interest. The ORF57 is a crucial regulatory protein for lytic gene expression of KSHV. Disruption of this gene translation will inevitably inhibit the replication of the virus in the host cell. Therefore, the ORF57 of KSHV could be a potential target for designing siRNA-based therapeutics. Considering both sequence preferences and target site accessibility, several online tools (i-SCORE Designer, Sfold web server) had been utilized to predict the siRNA guide strand against the ORF57. Subsequently, off-target filtration (BLAST), conservancy test (fuzznuc), and thermodynamics analysis (RNAcofold, RNAalifold, and RNA Structure web server) were also performed to select the most suitable siRNA sequences. Finally, two siRNAs were identified that passed all of the filtration phases and fulfilled the thermodynamic criteria. We hope that the siRNAs predicted in this study would be helpful for the development of new effective therapeutics against KSHV.