• Title/Summary/Keyword: Cell complex

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Ycs4 is Required for Efficient Double-Strand Break Formation and Homologous Recombination During Meiosis

  • Hong, Soogil;Choi, Eui-Hwan;Kim, Keun Pil
    • Journal of Microbiology and Biotechnology
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    • v.25 no.7
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    • pp.1026-1035
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    • 2015
  • Condensin is not only responsible for chromosome condensation, but is also involved in double-strand break (DSB) processing in the cell cycle. During meiosis, the condensin complex serves as a component of the meiotic chromosome axis, and mediates both proper assembly of the synaptonemal complex and DSB repair, in order to ensure proper homologous chromosome segregation. Here, we used the budding yeast Saccharomyces cerevisiae to show that condensin participates in a variety of chromosome organization processes and exhibits crucial molecular functions that contribute to meiotic recombination during meiotic prophase I. We demonstrate that Ycs4 is required for efficient DSB formation and establishing homolog bias at the early stage of meiotic prophase I, which allows efficient formation of interhomolog recombination products. In the Ycs4 meiosis-specific allele (ycs4S), interhomolog products were formed at substantial levels, but with the same reduction in crossovers and noncrossovers. We further show that, in prophase chromosomal events, ycs4S relieved the defects in the progression of recombination interactions induced as a result of the absence of Rec8. These results suggest that condensin is a crucial coordinator of the recombination process and chromosome organization during meiosis.

Cytocompatible Coating of Individual Mammalian Cells with Tannic Acid-Zn Complex (타닌산-아연 복합체를 이용한 단일수준에서의 동물세포 코팅)

  • Lee, Juno
    • KSBB Journal
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    • v.32 no.2
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    • pp.160-167
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    • 2017
  • Coating of individual cells with organic or inorganic materials has drawn a great deal of attention, because it provides the cells with physicochemical durability, which would contribute to the development of bioreactors, biosensor, and lab-on-a-chip, as well as to the fundamental studies in single cell-based biology. Although many strategies have been developed for coating of microbial cells, limited methods are available to coat mammalian cells because most mammalian cells do not have a robust membrane or exoskeleton. Instead, they are enclosed in a lipid bilayer, which is fluidic and vulnerable to changes in its environments. It is more difficult to treat mammalian cells in vitro than microbial cells because the surfaces of mammalian cells are not protected or reinforced by a tough coat. In this work, we report a cytocompatible and degradable nanocoat for mammalian cells. Three types of mammalian cells (HeLa cells, NIH 3T3 fibroblasts, and Jurkat T cells) were individually coated within metal-polyphenol. To maintain the viability of the mammalian cells, we performed the whole processes under strictly physiological culture conditions, and carefully selected nontoxic materials.

Effects of Korean Citrus junos and Medicinal Herbs on Liver Protection and Lipid Metabolism of Alcohol Fed Rats

  • Park, Kap-Joo;Song, Ha-Young;Lee, Hyung-Hoan
    • Korean Journal of Environmental Biology
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    • v.22 no.1
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    • pp.141-147
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    • 2004
  • In order to investigate whether or not the alcohol-treated rat liver cells can be protected by Korean Citrus junos and medicinal herbs, We compared the serum biochemistry of rats administered both alcohol and the complex of Korean Citrus junos and medicinal herbs to control rats treated with alcohol alone. The activities of Aspartate aminotransferase (AST) and Alanine aminotransferase (ALT) in the citron 3 (Citron 3, less mellowed citron which was ripened for three months)+Phellinus linteus, Alnus japonica, Dendropanax morbifera and citron 4 (Citron 4, completely mellowed citron which was ripened fer four months)+Phaseolus radiatus, Cordyceps militaris group were significantly low when compared with the negative control group (p<0.05). The levels of triglyceride (TG) in all experimental groups were significantly lower than the negative control group (p<0.05). The concentrations of total cholesterol in the citron 3+Phellinus linteus, Atnus japonica, Dendropanax morbifera and citron 4+Phaseolus radiatus, Cordyceps militaris, Phellinus linteus were lower than the negative control group (p<0.05). The activities of alcohol dehydyogenase (ADH) in all experimental groups were significantly high when compared with the normal control group (p<0.05). These results suggest that the complex of Korean Citrus junos and medecinal herbs could be an excellent candidate for protecting vat liver cell damage induced by alcohol.

The Plant Cellular Systems for Plant Virus Movement

  • Hong, Jin-Sung;Ju, Ho-Jong
    • The Plant Pathology Journal
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    • v.33 no.3
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    • pp.213-228
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    • 2017
  • Plasmodesmata (PDs) are specialized intercellular channels that facilitate the exchange of various molecules, including sugars, ribonucleoprotein complexes, transcription factors, and mRNA. Their diameters, estimated to be 2.5 nm in the neck region, are too small to transfer viruses or viral genomes. Tobacco mosaic virus and Potexviruses are the most extensively studied viruses. In viruses, the movement protein (MP) is responsible for the PD gating that allows the intercellular movement of viral genomes. Various host factors interact with MP to regulate complicated mechanisms related to PD gating. Virus replication and assembly occur in viral replication complex (VRC) with membrane association, especially in the endoplasmic reticulum. VRC have a highly organized structure and are highly regulated by interactions among the various host factors, proteins encoded by the viral genome, and the viral genome. Virus trafficking requires host machineries, such as the cytoskeleton and the secretory systems. MP facilitates the virus replication and movement process. Despite the current level of understanding of virus movement, there are still many unknown and complex interactions between virus replication and virus movement. While numerous studies have been conducted to understand plant viruses with regards to cell-to-cell movement and replication, there are still many knowledge gaps. To study these interactions, adequate research tools must be used such as molecular, and biochemical techniques. Without such tools, virologists will not be able to gain an accurate or detailed understanding of the virus infection process.

Characteristics of chondrocytes adhesion depends on geometric of 3-dimensional scaffolds fabricated by micro-stereolithography (마이크로 광 조형 기술로 제작된 3차원 인공지지체의 구조적 형태에 따른 연골세포의 생착 특성)

  • Lee S.J.;Kim B.;Lim G.;Kim S.W.;Rhie J.W.;Cho D.W.
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2006.05a
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    • pp.173-174
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    • 2006
  • Understanding chondrocyte behavior inside complex, three-dimensional environments with controlled patterning of geometrical factors would provide significant insights into the basic biology of tissue regenerations. One of the fundamental limitations in studying such behavior has been the inability to fabricate controlled 3D structures. To overcome this problem, we have developed a three-dimensional microfabrication system. This system allows fabrication of predesigned internal architectures and pore size by stacking up the photopolymerized materials. Photopolymer SL5180 was used as the material for 3D scaffolds. The results demonstrate that controllable and reproducible inner-architecture can be fabricated. Chondrocytes harvested from human nasal septum were cultured in two kinds of 3D scaffolds to observe cell adhesion behavior. Such 3D scaffolds might provide effective key factors to study cell behavior in complex environments and could eventually lead to optimum design of scaffolds in various tissue regenerations such as cartilage, bone, etc. in a near future.

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Proteomic Application in Cell Biology (세포생물학과 Proteomics 응용)

  • 김동욱
    • Korean Journal of Microbiology
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    • v.37 no.2
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    • pp.109-113
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    • 2001
  • As the complete genomic sequences accumulate, the use of global techniques became possible. DNA microarray is a powerful technology for measuring global mRNA levels. This method, however, does not provide information on post-translational modifications of proteins. In addition, mRNA levels do not strictly correlate with protein concentrations, especially for lower-abundance proteins. Therefore, studies at the level of transcription are not sufficient to understand cellular activity. Proteomic techniques to analyze protein expression and function at the large-scale have been developed and used. This review introduces a simple explanation for proteomic analysis and examples of how proteomics is applied in cell biology.

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Selective Cytotoxicity of New Platinum (II) Complex Containing 1,2-Diaminopropane (1,2-디아미노프로판을 배위자로 한 백금(II) 착체의 선택적 세포독성)

  • Rho, Young-Soo;Lee, Kyung-Tae;Chang, Sung-Goo;Jung, Jee-Chang
    • YAKHAK HOEJI
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    • v.42 no.5
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    • pp.494-499
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    • 1998
  • As part of a drug discovery program to discover more effective platinum-based anticancer drugs, a series of platinum complexes of 1,2-bis(diphenylphosphino)ethane(1,2-diaminopro pane)platinum(II)dinitrate (KHPC-070) has been evaluated in vitro against various tumor cell lines and normal kidney cells. The structure of this new compound was determined by elemental analysis, infrared spectroscopy (IR) and $^{13}carbon$ nuclear magnetic resonance (NMR). With the use of nine tumor cell lines, KHPC-070 exhibited a comparable cytotoxic to cisplatin. The cytotoxicity of KHPC-070 in normal cells was quite less than that of cisplatin using 3-(4.5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide (MTT) and [$^3H$]-thymidine uptake tests in rabbit renal proximal tubular cells and human renal cortical cells. Based on these results, KHPC-070 is considered to have more selective cytotoxicity toward cancer cells than normal human/rabbit kidney cells.

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The Overexpression of Oncogenic Nemo-like Kinase in Gastric Cancer (위암에서 새로운 종양원인 유전자 Nemo-like Kinase의 발현 증가)

  • Kim, Min Gyu;Jung, Kwang Hwa;Nam, Suk Woo
    • YAKHAK HOEJI
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    • v.56 no.6
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    • pp.358-363
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    • 2012
  • Nemo-like kinase (NLK), an evolutionarily conserved serine/threonine protein kinase, plays an important role in wide variety of developmental events. NLK phosphorylates T-cell factor/lymphoid enhancer factor (TCF/LEF) transcriptional complex and suppresses wnt signaling pathway through inhibition of ${\beta}$-catenin/TCF complex interaction. However, the function of NLK in gastric carcinogenesis has not been investigated. In the present study, we have examined whether the NLK gene is involved in the development and/or progression of gastric cancers. NLK expression was analyzed by immunohistochemical staining in 153 advanced gastric cancer specimens. Immunhistochemical analysis showed increased expression of NLK in 91 (59.5%) out of 153 gastric cancer specimens. Statistically, there was no significant relationship between altered expression of NLK protein and clinicopathological parameters, including tumor differentiation, location, lymph node metastasis. We identified that mRNA and protein expression of NLK was significantly up-regulated in human gastric cancer tissues compare to corresponding normal gastric tissues. In addition, we found that human gastric cancer cell lines exhibited relatively high expression of NLK, as compared with normal gastric cells. The results of this study suggest that aberrant regulation of NLK may contribute to the development or progression of gastric cancers and serve as a potential biomarker for advanced gastric cancer patients.

Redox Regulation of Apoptosis before and after Cytochrome C Release

  • Chen, Quan;Crosby, Meredith;Almasan, Alex
    • Animal cells and systems
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    • v.7 no.1
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    • pp.1-9
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    • 2003
  • Programmed cell death, or apoptosis, is one of the most studied areas of modern biology. Apoptosis is a genetically regulated process, which plays an essential role in the development and homeostasis of higher organisms. Mitochondria, known to play a central role in regulating cellular metabolism, was found to be critical for regulating apoptosis induced under both physiological and pathological conditions. Mitochondria are a major source of reactive oxygen species (ROS) but they can also serve as its target during the apoptosis process. Release of apoptogenic factors from mitochondria, the best known of which is cytochrome c, leads to assembly of a large apoptosis-inducing complex called the apoptosome. Cysteine pretenses (called caspases) are recruited to this complex and, following their activation by proteolytic cleavage, activate other caspases, which in turn target for specific cleavage a large number of cellular proteins. The redox regulation of apoptosis during and after cytochrome c release is an area of intense investigation. This review summarizes what is known about the biological role of ROS and its targets in apoptosis with an emphasis on its intricate connections to mitochondria and the basic components of cell death.

Identification of Protein Phosphatase 4 Inhibitory Protein That Plays an Indispensable Role in DNA Damage Response

  • Park, Jaehong;Lee, Jihye;Lee, Dong-Hyun
    • Molecules and Cells
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    • v.42 no.7
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    • pp.546-556
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    • 2019
  • Protein phosphatase 4 (PP4) is a crucial protein complex that plays an important role in DNA damage response (DDR), including DNA repair, cell cycle arrest and apoptosis. Despite the significance of PP4, the mechanism by which PP4 is regulated remains to be elucidated. Here, we identified a novel PP4 inhibitor, protein phosphatase 4 inhibitory protein (PP4IP) and elucidated its cellular functions. PP4IP-knockout cells were generated using the CRISPR/Cas9 system, and the phosphorylation status of PP4 substrates (H2AX, KAP1, and RPA2) was analyzed. Then we investigated that how PP4IP affects the cellular functions of PP4 by immunoprecipitation, immunofluorescence, and DNA double-strand break (DSB) repair assays. PP4IP interacts with PP4 complex, which is affected by DNA damage and cell cycle progression and decreases the dephosphorylational activity of PP4. Both overexpression and depletion of PP4IP impairs DSB repairs and sensitizes cells to genotoxic stress, suggesting timely inhibition of PP4 to be indispensable for cells in responding to DNA damage. Our results identify a novel inhibitor of PP4 that inhibits PP4-mediated cellular functions and establish the physiological importance of this regulation. In addition, PP4IP might be developed as potential therapeutic reagents for targeting tumors particularly with high level of PP4C expression.