• Molecular & Cellular Toxicology
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• v.4 no.2
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• pp.164-169
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• 2008

Methylmercury (MeHg) is known to have devastating effects on the mammalian nervous system. In order to characterize the mechanism of MeHg-induced neurotoxicity, we investigated the analysis of transcriptional profiles on human 8k cDNA microarray by treatment of $1.4{\mu}M$ MeHg at 3, 12, 24 and 48h in human neuroblastoma SH-SY5Y cell line. Some of the identified genes by MeHg treatment were significant at early time points (3h), while that of others was at late time points (48h). The early response genes that may represent those involved directly in the MeHg response included pantothenate kinase 3, a kinase (PRKA) anchor protein (yotiao) 9, neurotrophic tyrosine kinase, receptor, type 2 gene, associated with NMDA receptor activity regulation or perturbations of central nervous system homeostasis. Also, when SH-SY5Y cells were subjected to a longer exposure (48h), a relative increase was noted in a gene, glutamine-fructose-6-phosphate transaminase 1, reported that overexpression of this gene may lead to the increased resistance to MeHg. To confirm the alteration of these genes in cultured neurons, we then applied real time-RT PCR with SYBR green. Thus, this result suggests that a neurotoxic effect of the MeHg might be ascribed that MeHg alters neuronal receptor regulation or homeostasis of neuronal cells in the early phase. However, in the late phase, it protects cells from neurotoxic effects of MeHg.

• Journal of Physiology & Pathology in Korean Medicine
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• v.18 no.2
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• pp.553-560
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• 2004

In the present study, we investigated the anti-proliferative effects of aqueous extract of Wikyung-tang(WKT) on the growth of human lung carcinoma cell line A549. WKT treatment declined the cell viability and proliferation of A549 cells in a concentration-dependent manner. The anti-proliferative effects by WKT treatment in A549 cells was associated with morphological changes such as membrane shrinking and cell rounding up. WKT treatment induced an inhibition and/or degradation of apoptotic target proteins such poly(ADP-ribose) polymerase (PARP) and phospholipase C-γ1 (PLC-γ1). WKT treatment did not affect the levels of other Bcl-2 family gene products, such as Bcl-2, Bax and Bad. Western blot analysis and RT-PCT data revealed that the levels of tumor suppressor p53 and cyclin-dependent kinase inhibitor p21 were induced by WKT treatment in A549 cells. Additionally, WKT treatment induced the down-regulation of telomerase reverse transcriptase mRNA (hTERT) expression of A549 cells, however, the levels of other telomere-regulatory gene products were not affected. Taken together, these findings suggest that WKT-induced inhibition of human lung cancer cell proliferation is associated with the induction of apoptotic cell death via regulation of several major growth regulatory gene products and WKT may have therapeutic potential in human lung cancer.

• Journal of Microbiology and Biotechnology
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• v.18 no.6
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• pp.1033-1039
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• 2008

A 3-kb HindIII fragment bearing the cry6Aa2 gene and the adjacent and intergenic regions was cloned from Bacillus thuringiensis strain YBT-1518. Two open reading frames (ORFs), namely, orf1 (termed cry6Aa2) and orf2 that were separated by an inverted-repeat sequence were identified. orf1 encoded a 54-kDa protein that exhibited high toxicity to the plant-parasitic nematode Meloidogyne hapla. The orf2 expression product was not detected by SDS-PAGE, but its mRNA was detected by RT-PCR. The orf2 coexpressed with orf1 at a high level in the absence of the inverted-repeat sequence, whereas, the expression level of otfl was decreased. When orf2 was mutated, the level of orf1 expression was enhanced obviously. In conclusion, the inverted-repeat sequence disturbs orf2 expression, and the orf2 downregulates orf1 expression. This is an example of novel negative regulation in B. thuringiensis and a potential method for enhancing the expression level of cry genes.

• Journal of Microbiology and Biotechnology
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• v.15 no.5
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• pp.1060-1066
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• 2005

Under environmental stress, such as strong irradiance or nitrogen deficiency, unicellular green algae of the genus Haematococcus accumulate secondary carotenoids, i.e. astaxanthin, in the cytosol. The induction and regulation of astaxanthin biosynthesis in microalgae has recently received considerable attention owing to the increasing use of secondary carotenoids as a source of pigmentation for fish aquacultures, and as a potential drug in cancer prevention as a free-radical quencher. Accordingly, this study generated expressed sequence tags (ESTs) from a library constructed from astaxanthin-induced Haematococcus pluvialis. Partial sequences were obtained from the 5' ends of 1,858 individual cDNAs, and then grouped into 1,025 non-overlapping sequences, among which 708 sequences were singletons, while the remainder fell into 317 clusters. Approximately $63\%$ of the EST sequences showed similarity to previously described sequences in public databases. H. pluvialis was found to consist of a relatively high percentage of genes involved in genetic information processing ($15\%$) and metabolism ($11\%$), whereas a relatively low percentage of sequences was involved in the signal transduction ($3\%$), structure ($2\%$), and environmental information process ($3\%$). In addition, a relatively large fraction of H. pluvialis sequences was classified as genes involved in photosynthesis ($9\%$) and cellular process ($9\%$). Based on this EST analysis, the full-length cDNA sequence for superoxide dismutase (SOD) of H. pluvialis was cloned, and the expression of this gene was investigated. The abundance of SOD changed substantially in response to different culture conditions, indicating the possible regulation of this gene in H. pluvialis.

• Reproductive and Developmental Biology
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• v.30 no.2
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• pp.93-97
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• 2006

To study the signaling effect of insulin-like growth factor-I(IGF-1), transgenic mice containing IGF-1 Receptor (IGF-1R) cDNA fused to metallothionein promoter were produced by DNA microinjection into the pronucleus of mouse zygote. Three founders were produced with transgenic mice containing IGF-1R gene. Transgenic mice lines contained approximately $4{\sim}20$ copies of transgenes per cell and transmission of this gene into the progeny with Mendelian manner were determined. The founder mice were mated with normal mice to produce $F_1$ mice and then $F_2$ mice. Transmission rates of IGF-1R transgene in the progeny mice were $25{\sim}60%$ in $F_1$ generation and $40{\sim}50%$ in $F_2$ generation. The mRNA expression of IGF-1R transgene in liver was analyzed using RT-PCR for IGF-1R gene in liver. When body weights of transgenic pups were measured during 4, 10 and 14 weeks after birth, IGF-1R transgenic mice grew faster than non transgenic littermates. This study indicated that growth regulation by IGF-1 signaling through IGF-1R can be elucidated using IGF-1R transgenic mice.

• Asian-Australasian Journal of Animal Sciences
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• v.20 no.6
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• pp.850-855
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• 2007

Leptin is the adipocyte-specific product of the obese gene and plays a major role in food intake and energy metabolism. Leptin research was mainly focused on mammalian species, but understanding of leptin and its function in poultry is very poor. In this study, the duck leptin gene was amplified using the reverse transcription-polymerase chain reaction (RT-PCR) from duck liver RNA. The cDNA fragment was inserted into the pET-28a expression vector, and the resulting plasmid was expressed in Escherichia coli BL21 (DE3). Experimental mice were given an intraperitoneal injection of 10 mg/kg leptin dissolved in phosphate buffered saline (PBS), while the control mice were injected with PBS. The effect of leptin on food intake, body weight and fatty deposition in mice was detected. Sequence analysis revealed that duck leptin had a length of 438 nucleotides which encoded a peptide with 146 amino acid residues. The sequence shares highly homology to other animals. The coding sequence of duck leptin was 84 and 86% identical to human and pig leptin nucleotides sequence. Highest identity was with the rat coding sequence (95%). The identity of the amino acid sequence was 84, 82 and 96% respectively compared to that of the human, pig and rat. Results of SDS-PAGE analysis indicated that a fusion protein was specifically expressed in E. coli BL21 (DE3). The purified product was found to be biologically active during tests. Continuous administration of recombinant duck leptin inhibited food intake. Despite the decrease of food intake, leptin significantly induced body weight and fatty deposition. These changes were accompanied by a significant down-secretion of plasma glucose, cholesterol, triglyceride and insulin levels in mice. The observations provide evidence for an inhibitory effect of leptin in the regulation of food intake and for a potential role of duck leptin in the regulation of lipogenesis.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.28 no.3
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• pp.7-39
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• 2002

The extensive variation in human cutaneous pigmentation is mainly due to differences in the rate of melanin synthesis by epidermal melanocytes, the relative amounts of eumelanin and pheomelanin synthesized, and the manner and rate of transfer of melanosomes from melanocytes to keratinocytes. Pigmentation is a complex trait that is regulated genetically and environmentally. One gene that has been receiving a lot of attention is the gene for the melanocortin 1 receptor The extensive polymorphism of this gene in human populations suggests its significance in the diversity of pigmentation. Exposure to solar ultraviolet radiation (UV) results in increased synthesis of a variety of growth factors, cytokines and hormones, and in modulation of their receptors in the epidermis. Knowledge about the regulation of pigmentation has led to strategies for clinical treatment of hyperpigmented skin lesions. Three main strategies are: 1) the use of chemicals that interfere with the melanin synthetic pathway, 2) the design of peptides or peptide-mimetics based on the structure of hormones that regulate eumelanin synthesis, and 3) the use of agents that reduce melanosome transfer from melanocytes to keratinocytes. All three strategies are expected to induce hypopigmentation, by inhibiting total melanin synthesis, eumelanin production, or the epidermal melanin unit, respectively.

• Molecules and Cells
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• v.40 no.6
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• pp.426-433
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• 2017

Ephrin-A5 has been implicated in the regulation of brain morphogenesis and axon pathfinding. In this study, we used bacterial homologous recombination to express a LacZ reporter in various ephrin-A5 BAC clones to identify elements that regulate ephrin-A5 gene expression during mesencephalon development. We found that there is mesencephalon-specific enhancer activity localized to a specific +25.0 kb to +30.5 kb genomic region in the first intron of ephrin-A5. Further comparative genomic analysis indicated that two evolutionary conserved regions, ECR1 and ECR2, were present within this 5.5 kb region. Deletion of ECR1 from the enhancer resulted in disrupted mesencephalon-specific enhancer activity in transgenic embryos. We also found a consensus binding site for basic helix-loop-helix (bHLH) transcription factors (TFs) in a highly conserved region at the 3'-end of ECR1. We further demonstrated that specific deletion of the bHLH TF binding site abrogated the mesencephalon-specific enhancer activity in transgenic embryos. Finally, both electrophoretic mobility shift assay and luciferase-based transactivation assay revealed that the transcription factor Ascl1 bound the bHLH consensus binding site in the mesencephalon-specific ephrin-A5 enhancer in vitro. Together, these results suggest that the bHLH TF binding site in ECR1 is involved in the positive regulation of ephrin-A5 gene expression during the development of the mesencephalon.

• The Plant Pathology Journal
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• v.29 no.4
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• pp.364-373
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• 2013

It has been known that most regulation of pathogenicity factor (rpf ) genes in xanthomonads regulates virulence in response to the diffusible signal factor, DSF. Although many rpf genes have been functionally characterized, the function of rpfE is still unknown. We cloned the rpfE gene from a Xanthomonas oryzae pv. oryzae (Xoo) Korean race KACC10859 and generated mutant strains to elucidate the role of RpfE with respect to the rpf system. Through experiments using the rpfE-deficient mutant strain, we found that mutation in rpfE gene in Xoo reduced virulence, swarm motility, and production of virulence factors such as cellulase and extracellular polysaccharide. Disease progress by the rpfE-deficient mutant strain was significantly slowed compared to disease progress by the wild type and the number of the rpfE-deficient mutant strain was lower than that of the wild type in the early phase of infection in the inoculated rice leaf. The rpfE mutant strain was unable to utilize sucrose or xylose as carbon sources efficiently in culture. The mutation in rpfE, however, did not affect DSF synthesis. Our results suggest that the rpfE gene regulates the virulence of Xoo under different nutrient conditions without change of DSF production.

• BMB Reports
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• v.34 no.4
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• pp.379-384
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• 2001

The cDNA encoding ribosomal protein was identified from a cDNA library of Schizosaccharomyces pombe. The nucleotide sequence of the 548 by cDNA clone reveals an open reading frame, which encodes a putative protein of 166 amino acids with a molecular mass of 18.3 kDa. The amino acid sequence of the S. pombe L11 protein is highly homologous with those of rat and fruit, while it is clearly less similar to those of prokaryotic counterparts. The 1,044 by upstream sequence, and the region encoding N-terminal 7 amino acids of the genomic DNA were fused into the promoterless $\beta$-galactosidase gene of the shuttle vector YEp357 in order to generate the fusion plasmid pHY L11. Synthesis of $\beta$-galactosidase from the fusion plasmid varied according to the growth curve. It decreased significantly in the growth-arrested yeast cells that were treated with aluminum chloride and mercuric chloride. However, it was enhanced by treatments with cadmium chloride ($2.5\;{\mu}M$), zinc chloride ($2.5\;{\mu}M$), and hydrogen peroxide (0.5 mM). This indicates that the expression of the L,11 gene could be induced by oxidative stress.