• The Korean Journal of Zoology
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• v.38 no.4
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• pp.542-549
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• 1995

The effect of extraceflular matrix (ECM) protein on the neuronai differentiation of SI(-N-SH and IMR-32 human neuroblastoma cell lines was examined. When ceils were cultured on the laminin/collagen coated plate for 7 days, the extensive neurite outgrowth was observed In IMR-32. To address the reason why IMR-32 cell llne did not respond to ECM proteins, the ECM mediated early signalling mechanisms were analysed in both SK-N-SH and IMR-32. When cells were plated on the laminin/collagen coated plates, tyrosine phosphorylated proteins were Increased within an hour In both of these cells. Moreover, the foaal adhesion IlInase (FAK) was tyrosine phosphorylated in both of these two cell lines. These results suggest that the ECM mediated early signalling mechanism was normal in IMR-32 cell line. The expression of both NSE and Bcl-2 was increased by ECM treatment in SK-N-SH. However, these components were not changed by ECM In IMR 32 cells to ECM component Is likely due to the abnomality of the transcriptional regulation mechanism which Is responsible for the neuronal differentiation.

• Molecules and Cells
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• v.21 no.2
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• pp.251-260
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• 2006

During mitosis, genomic integrity is maintained by the proper coordination of anaphase entry and mitotic exit via mitotic checkpoints. In budding yeast, mitotic exit is controlled by a regulatory cascade called the mitotic exit network (MEN). The MEN is regulated by a small GTPase, Tem1p, which in turn is controlled by a two-component GAP, Bfa1p-Bub2p. Recent results suggested that phosphorylation of Bfa1p by the polorelated kinase Cdc5p is also required for triggering mitotic exit, since it decreases the GAP activity of Bfa1p-Bub2p. However, the dispensability of GEF Lte1p for mitotic exit has raised questions about regulation of the MEN by the GTPase activity of Tem1p. We isolated a Bfa1p mutant, $Bfa1p^{E438K}$, whose overexpression only partially induced anaphase arrest. The molecular and biochemical functions of $Bfa1p^{E438K}$ are similar to those of wild type Bfa1p, except for decreased GAP activity. Interestingly, in $BFA1^{E438K}$ cells, the MEN could be regulated with nearly wild type kinetics at physiological temperature, as well as in response to various checkpoint-activating signals, but the cells were more sensitive to spindle damage than wild type. These results suggest that the GAP activity of Bfa1p-Bub2p is responsible for the mitotic arrest caused by spindle damage and Bfa1p overproduction. In addition, the viability of cdc5-2 ${\Delta}bfa1 $ cells was not reduced by $BFA1^{E438K}$, suggesting that Cdc5p also regulates Bfa1p to activate mitotic exit by other mechanism(s), besides phosphorylation.

• Biomolecules & Therapeutics
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• v.27 no.3
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• pp.302-310
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• 2019

Melanoma cells have been shown to respond to BRAF inhibitors; however, intrinsic and acquired resistance limits their clinical application. In this study, we performed RNA-Seq analysis with BRAF inhibitor-sensitive (A375P) and -resistant (A375P/Mdr with acquired resistance and SK-MEL-2 with intrinsic resistance) melanoma cell lines, to reveal the genes and pathways potentially involved in intrinsic and acquired resistance to BRAF inhibitors. A total of 546 differentially expressed genes (DEGs), including 239 up-regulated and 307 down-regulated genes, were identified in both intrinsic and acquired resistant cells. Gene ontology (GO) analysis revealed that the top 10 biological processes associated with these genes included angiogenesis, immune response, cell adhesion, antigen processing and presentation, extracellular matrix organization, osteoblast differentiation, collagen catabolic process, viral entry into host cell, cell migration, and positive regulation of protein kinase B signaling. In addition, using the PAN-THER GO classification system, we showed that the highest enriched GOs targeted by the 546 DEGs were responses to cellular processes (ontology: biological process), binding (ontology: molecular function), and cell subcellular localization (ontology: cellular component). Ingenuity pathway analysis (IPA) network analysis showed a network that was common to two BRAF inhibitorresistant cells. Taken together, the present study may provide a useful platform to further reveal biological processes associated with BRAF inhibitor resistance, and present areas for therapeutic tool development to overcome BRAF inhibitor resistance.

• Molecules and Cells
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• v.44 no.1
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• pp.13-25
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• 2021

Apoptosis and compensatory proliferation, two intertwined cellular processes essential for both development and adult homeostasis, are often initiated by the mis-regulation of centrosomal proteins, damaged DNA, and defects in mitosis. Fly Anastral spindle 3 (Ana3) is a member of the pericentriolar matrix proteins and known as a key component of centriolar cohesion and basal body formation. We report here that ana3m19 is a suppressor of lethality induced by the overexpression of Sol narae (Sona), a metalloprotease in a disintegrin and metalloprotease with thrombospondin motif (ADAMTS) family. ana3m19 has a nonsense mutation that truncates the highly conserved carboxyl terminal region containing multiple Armadillo repeats. Lethality induced by Sona overexpression was completely rescued by knockdown of Ana3, and the small and malformed wing and hinge phenotype induced by the knockdown of Ana3 was also normalized by Sona overexpression, establishing a mutually positive genetic interaction between ana3 and sona. p35 inhibited apoptosis and rescued the small wing and hinge phenotype induced by knockdown of ana3. Furthermore, overexpression of Ana3 increased the survival rate of irradiated flies and reduced the number of dying cells, demonstrating that Ana3 actively promotes cell survival. Knockdown of Ana3 decreased the levels of both intra- and extracellular Sona in wing discs, while overexpression of Ana3 in S2 cells dramatically increased the levels of both cytoplasmic and exosomal Sona due to the stabilization of Sona in the lysosomal degradation pathway. We propose that one of the main functions of Ana3 is to stabilize Sona for cell survival and proliferation.

• Korean Journal of Microbiology
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• v.41 no.1
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• pp.1-7
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• 2005

Methylophaga aminosulfidovorans SK1 (KCTC 10323 BP) can utilize trimethylamine as a sole carbon, nitrogen, and energy source. The bacterial flavin-containing monooxygenase (bFMO) gene was identified in the strain and the recombinant enzyme expressed in E. coli oxidized trimethylamine. To study the function and regulation of the bfmo, over 8,000 nucleotide sequences of the neighboring regions including the bfmo were determined. Three open reading frames proceeding to the bfmo gene encoded analogues to highly conserved nitrate/nitrite sensing two-component system regulators and a methyl accepting protein. Two small open reading frames just downstream of the bfmo gene showed no similar proteins of known functions but the sequences were conserved among other bacteria. Reverse transcription-polymerase chain reaction analysis showed that the six putative genes consisted of three transcription units. The three regulatory genes located upstream of the bfmo gene formed two separate transcription units. The bfmo and the two downstream genes were transcribed from a single promoter.

• Journal of Microbiology and Biotechnology
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• v.20 no.2
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• pp.301-310
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• 2010

Bacillus subtilis strains produce a broad spectrum of bioactive peptides. The lipopeptide surfactin belongs to one well-known class, which includes amphiphilic membrane-active biosurfactants and peptide antibiotics. Both the srfA promoter and the ComP-ComA signal transduction system are an important part of the factor that results in the production of surfactin. Bs-M49, obtained by means of low-energy ion implantation in wild-type Bs-916, produced significantly lower levels of surfactin, and had no obvious effects against R. solani. Occasionally, we found strain Bs-M49 decreased spore formation and the development of competence. Blast comparison of the sequences from Bs-916 and M49 indicate that there is no difference in the srfA operon promoter PsrfA, but there are differences in the coding sequence of the comA gene. These differences result in three missense mutations within the M49 ComA protein. RT-PCR analyses results showed that the expression levels of selected genes involved in competence and sporulation in both the wild-type Bs-916 and mutant M49 strains were significantly different. When we integrated the comA ORF into the chromosome of M49 at the amyE locus, M49 restored hemolytic activity and antifungal activity. Then, HPLC analyses results also showed the comA-complemented strain had a similar ability to produce surf actin with wild-type strain Bs-916. These data suggested that the mutation of three key amino acids in ComA greatly affected the biological activity of Bacillus subtilis. ComA protein 3D structure prediction and motif search prediction indicated that ComA has two obvious motifs common to response regulator proteins, which are the N-terminal response regulator receiver motif and the C-terminal helix-turn-helix motif. The three residues in the ComA N-terminal portion may be involved in phosphorylation activation mechanism. These structural prediction results implicate that three mutated residues in the ComA protein may play an important role in the formation of a salt-bridge to the phosphoryl group keeping active conformation to subsequent regulation of the expression of downstream genes.

• Korean Journal of Cognitive Science
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• v.33 no.2
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• pp.95-107
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• 2022

Facial processing of different racial origin has been investigated at various levels including perceptual, emotional, and socio-cultural processing. Particularly, a good deal of studies have been conducted to show "other race effect (ORE)" to indicate that subtle facial information such as identity or emotional expressions are often under-processed in racial out-group members. However, few studies have investigated whether attentional modulation toward racial out-group faces could explain ORE. We investigated whether novelty-driven attentional mechanism is involved in face perception using event-related potential (ERP). Twenty-two Korean (KR) and nine Caucasian-American (AM) participants were presented with emotional faces from the two racial origins while they performed a gender categorization task. KRs showed significantly greater P3 amplitudes to AM than to KR faces indicating that the early attentional processing underlies differential perception of racial out-group faces. Interestingly, P3 was not up-regulated in the AM subjects when they were presented with KR faces, perhaps due to massive habituation to KR faces during everyday social interaction. These results indicate that racial out-group faces are highly salient stimuli which automatically occupy attentional resources, but easily habituated with repeated exposure to the racial-out group.

• Journal of Ginseng Research
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• v.36 no.2
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• pp.161-168
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• 2012

The abnormal maturation and ossification of articular chondrocytes play a central role in the pathogenesis of osteoarthritis (OA). Inhibiting the enzymatic degradation of the extracellular matrix and maintaining the cellular phenotype are two of the major goals of interest in managing OA. Ginseng is frequently taken orally, as a crude substance, as a traditional medicine in Asian countries. Ginsenoside $Rb_1$, a major component of ginseng that contains an aglycone with a dammarane skeleton, has been reported to exhibit various biological activities, including anti-inflammatory and anti-tumor effects. However, a chondroprotective effect of ginsenoside $Rb_1$ related to OA has not yet been reported. The purpose of this study was to demonstrate the chondroprotective effect of ginsenoside $Rb_1$ on the regulation of pro-inflammatory factors and chondrogenic genes. Cultured rat articular chondrocytes were treated with 100 ${\mu}M$ ginsenoside $Rb_1$ and/or 500 ${\mu}M$ hydrogen peroxide ($H_2O_2$) and assessed for viability, reactive oxygen species production, nitric oxide (NO) release, and chondrogenic gene expression. Ginsenoside $Rb_1$ treatment resulted in reductions in the levels of pro-inflammatory cytokine and NO in $H_2O_2$-treated chondrocytes. The expression levels of chondrogenic genes, such as type II collagen and SOX9, were increased in the presence of ginsenoside $Rb_1$, whereas the expression levels of inflammatory genes related to chondrocytes, such as MMP1 and MMP13, were reduced by approximately 50%. These results suggest that ginsenoside $Rb_1$ has potential for use as a therapeutic agent in OA patients.

• Applied Microscopy
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• v.30 no.1
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• pp.1-9
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• 2000

The wandering spider, Pardosa astrigera, had four pairs of ocelli that arranged in three rows on the cephalothorax. Along the anterior margin lay a pair of small anterior median (AM) eye flanked on each side by anterior lateral (AL) eye. Two large posterior median (PM) eye was situated on the clypeus behind the anterior row and still more posteriorly was a pair of posterior lateral (PL) eye. The visual cell of retina consisted of cell body, rhabdome, and intermediate segment. Bipolar neuron was found in anterior median eye (principal eye) and unipolar neuron in others (secondary eye). Rhabdome showed that arranged in PMeye and PLeye. But rhabdomes of AMeye and ALeye were irregular in retina. Except AMeye, incontinuous tapetum found in ALeye, PMeye, PLeye. Anterior median eye was similar to anterior lateral eye in length and posterior median eye similar to posterior lateral eye. Component size of eye were similar to 4 pairs eye in cornea. Size of lens, cell body, and rhabdome was similar not only anterior median eye and anterior lateral eye but also posterior median eye and posterior lateral eye. Vitreous body was large posterior median eye than others.

• Journal of Life Science
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• v.19 no.11
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• pp.1637-1643
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• 2009

Shikonin, a component of Lithospermum erythrorhizon Sieb. et Zucc, exerts various characteristics such as anti-inflammatory, anti-cancer and anti-obesity functions. To elucidate the molecular mechanism of shikonin-induced inhibition of adipogenesis, we analyzed the mRNA expression level of various adipogenesis-related factors including C/EBPs (CCAAT/enhancerbinding proteins) and $PPAR{\gamma}$ (peroxisome proliferator-activated receptor $\gamma$). The data showed that mRNA expressions of C/$EBP{\beta}$ and C/$EPB{\delta}$ were only slightly changed by shikonin treatment, but mRNA expressions of $PPAR{\gamma}$ and C/$EPB{\alpha}$ were significantly down-regulated. Then, we tested whether upstream regulators of C/$EBP{\beta}$ and $PPAR{\gamma}$ were involved in anti-adipogenesis of shikonin. C/$EBP{\gamma}$ and CHOP (C/EBP homologous protein), which are upstream regulators of C/$EBP{\beta}$, were not affected by shikonin treatment. On the contrary, the mRNA level of KROX20 was markedly down-regulated by shikonin treatment. These results suggest that KROX20 might regulate downstream factors of adipogenesis through C/$EBP{\beta}$-independent pathway. The expression of KLF15 (Kruppel-like factor15), which is a member of KLF family and is a upstream regulator of $PPAR{\gamma}$, was dramatically decreased by shikonin treatment, but KLF2 was not changed. Shikonin had no impact on the expression of KLF5 in the early stage of adipogenesis, but shikonin increased expression of KLF5 in the late stage of adipogenesis. Even though mRNA expression of KLF5 was moderately changed by shikonin treatment, its effect may be small compared with the effect of KLF15, which was markedly inhibited. Taken together, these results suggest that shikonin inhibits adipogenesis through the down-regulation of $PPAR{\gamma}$ and C/$EPB{\alpha}$, which is mediated by the down-regulation of two pro-adipogenic factors, KROX20 and KLF15.