• Development and Reproduction
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• v.15 no.3
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• pp.187-195
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• 2011

X chromosome inactivation (XCI) is a process that enables mammalian females to ensure the dosage compensation for X-linked genes. Investigating the mechanism of XCI might provide deeper understandings of chromosomal silencing, epigenetic regulation of gene expressions, and even the course of evolution. Studies on mammalian XCI conducted with mice have revealed many fundamental findings on XCI. However, difference of murine and human XCI necessitates the further investigation in human XCI. Recent success in reprogramming of differentiated cells into pluripotent stem cells showed the reversibility of XCI in vitro, X chromosome reactivation (XCR), which provides another tool to study the change in X chromosome status. This review summarizes the current knowledge of XCI during early embryonic development and describes recent achievements in studies of XCI in reprogramming process.

• BMB Reports
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• v.46 no.1
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• pp.9-16
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• 2013

In mammalian cells, aberrant transcripts harboring a premature termination codon (PTC) can be generated by abnormal or inefficient biogenesis of mRNAs or by somatic mutation. Truncated polypeptides synthesized from these aberrant transcripts could be toxic to normal cellular functions. However, mammalian cells have evolved sophisticated mechanisms for monitoring the quality of mRNAs. The faulty transcripts harboring PTC are subject to nonsense-mediated mRNA decay (NMD), nonsense-mediated translational repression (NMTR), nonsense-associated alternative splicing (NAS), or nonsense-mediated transcriptional gene silencing (NMTGS). In this review, we briefly outline the molecular characteristics of each pathway and suggest mRNA quality control mechanisms as a means to regulate normal gene expression.

• Proceedings of the Korean Society of Toxicology Conference
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• 2001.10a
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• pp.108-109
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• 2001

Resveratrol (3, 5, 4'-trihydroxystilbene) is a naturally occuring molecule, synthesized by several plants in response to different stresses. Recently many studies performed in human and mammalian cells demonstrated the involment of resveratrol in the modulation of several biological processes (inhibition of lipidic peroxidation, platelet aggregation, estrogenic activity). It has also been found to possess scavenging and antioxidant properties (1).(omitted)

• Korean Journal of Microbiology
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• v.25 no.3
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• pp.165-172
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• 1987

An expression vector in a mammalian cell was constructed using the origin of replication (OR) and the promoters of SV40. The plasmid pSVOE was constructed by inserting SV40 DNA fragment (1, 118bp) containing SV40 OR and promoters into pBR322-1, and then a multiple cloning sequence was inserted at the immediate downstream of the late promoter of SV40 in the pSVOE vector. The plasmid was named pSVML. As a selection marker, thymidine kinase gene of herpes simplex virus with its promoter was inserted into EcoRI site of pSVML and the recombinant was named pSVML-TKp. To test the expression capacity of foreigen gene inserted at the multiple cloning site of pSVML, the thymidine kinase gene without its own promoter was inserted at the BamHI site of pSVML. The recombinant was named pSVML-TK. These plasmids, pSVML-TKp and pSVML-TK, were transfected into COS cells with calcium phosphate precipitation method. The thymidine kinase activity was significantly increased in both transfected cells.

• Journal of Microbiology and Biotechnology
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• v.30 no.9
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• pp.1290-1296
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• 2020

Recently, it was reported that entire mammalian mtDNA genomes could be transplanted into the mitochondrial networks of yeast, where they were accurately and stably maintained without rearrangement as intact genomes. Here, it was found that engineered mtDNA genomes could be readily transferred to and steadily maintained in the mitochondria of genetically modified yeast expressing the mouse mitochondrial transcription factor A (Tfam), one of the mitochondrial nucleoid proteins. The transferred mtDNA genomes were stably retained in the Tfam-expressing yeast cells for many generations. These results indicated that the engineered mouse mtDNA genomes introduced in yeast mitochondria could be relocated into the mitochondria of other cells and that the transferred genomes could be maintained within a mitochondrial environment that is highly amenable to mimicry of the biological conditions in mammalian mitochondria.

• Bulletin of the Korean Chemical Society
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• v.18 no.11
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• pp.1204-1207
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• 1997

Effects of exogenous glycerophospholipids on oleate-dependent phospholipase D (PLD) activity were studied in lymphocytic mouse leukemia L1210 cells and in solubilized microsomal phospholipase D of rat brain. Among the phospholipids tested phosphatidic acid had the most stimulatory effects on both PLD activities up to about 3 folds. Lysophosphatidic acid also showed promoting effect on microsomal PLD activity but much less on L1210 cells compared to that of phosphatidic acid. While phosphatidylethanolamine increased PLD activity slightly, phosphatidylinositides were nearly ineffective in the tested sources. The stimulatory effect of phosphatidic acid observed can be utilized to improve the in vitro assay system for oleate-dependent PLD in mammalian sources.

• Proceedings of the PSK Conference
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• 2003.04a
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• pp.178.2-178.2
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• 2003

To develope the novel anti-allergic drug, many sophoricoside derivatives were synthesized. Among these derivatives, JSH-II-3, JSH-Ⅵ-3, JSH-Ⅶ-3, and JSH-Ⅷ-3 were selected and subjected to high throughput toxicity screening (HTTS) because they revealed strong IL-5 inhibitory activity and limitation of Quantity. Mouse lymphoma thymidine kinase ($tk^{+/-}$) gene assay(MOLY) and single cell gel electrophoresis (Comet) assay in mammalian cells were used as HTTS tool in our laboratory. (omitted)

• Proceedings of the PSK Conference
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• 2003.10b
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• pp.171.2-172
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• 2003

Over the past few years, a variety of macrocyclic salicylate natural products have been isolated from both terrestrial and marine sources based on their ability to induce a particular phenotype in mammalian cells. Extracts of the myxobacterium Chondromyces showed high cytotoxicity against cultivated mammalian cells and bio-guided fractionation revealed the cytotoxicity was due to one main metabolite identified as the novel macrolide apicularen A. Beginning to understand the molecular basis for these distinct activities will require structure-function correlation studies and the development of synthetic chemistry in this area. (omitted)

• Journal of Veterinary Science
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• v.24 no.4
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• pp.53.1-53.12
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• 2023

Background: Mammalian orthoreovirus type 3 (MRV3), which is responsible for gastroenteritis in many mammalian species including pigs, has been isolated from piglets with severe diarrhea. However, the use of pig-derived cells as an infection model for swine-MRV3 has rarely been studied. Objectives: This study aims to establish porcine intestinal organoids (PIOs) and examine their susceptibility as an in vitro model for intestinal MRV3 infection. Methods: PIOs were isolated and established from the jejunum of a miniature pig. Established PIOs were characterized using polymerase chain reaction (PCR) and immunofluorescence assays (IFAs) to confirm the expression of small intestine-specific genes and proteins, such as Lgr5, LYZI, Mucin-2, ChgA, and Villin. The monolayered PIOs and three-dimensional (3D) PIOs, obtained through their distribution to expose the apical surface, were infected with MRV3 for 2 h, washed with Dulbecco's phosphate-buffered saline, and observed. Viral infection was confirmed using PCR and IFA. We performed quantitative real-time reverse transcription-PCR to assess changes in viral copy numbers and gene expressions linked to intestinal epithelial genes and antiviral activity. Results: The established PIOs have molecular characteristics of intestinal organoids. Infected PIOs showed delayed proliferation with disruption of structures. In addition, infection with MRV3 altered the gene expression linked to intestinal epithelial cells and antiviral activity, and these effects were observed in both 2D and 3D models. Furthermore, viral copy numbers in the supernatant of both models increased in a time-dependent manner. Conclusions: We suggest that PIOs can be an in vitro model to study the infection mechanism of MRV3 in detail, facilitating pharmaceutical development.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.30 no.1
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• pp.11-21
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• 2008

Aim of the study: Thermal stress is a central determinant of osseous surgical outcomes. Interestingly, the temperatures measured during endosseous surgeries coincide with the temperatures that elicit the heat shock response of mammalian cells. The heat shock response is a coordinated biochemical response that helps to protect cells from stresses of various forms. Several protective proteins, termed heat shock proteins (hsp) are produced as part of this response. To begin to understand the role of the stress response of osteoblasts during surgical manipulation of bone, the heat shock protein response was evaluated in osteoblastic cells. Materials & methods: With primary cell culture studies and ROS 17/2.8 osteoblastic cells transfected with hsp27 encoding vectors culture studies, the thermal stress response of mammalian osteoblastic cells was evaluated by immunohistochemistry and western blot analysis. Results: Immunocytochemistry indicated that hsp27 was present in unstressed osteoblastic cells, but not fibroblastic cells. Primarily cultured osteoblasts and fibroblasts expressed the major hsp in response to thermal stress, however, the small Mr hsp, hsp27 was shown to be a constitutive product only in osteoblasts. Creation of stable transformed osteoblastic cells expressing abundant hsp27 protein was used to demonstrate that hsp27 confers stress resistance to osteoblastic cells. Conclusions: The demonstrable presence and function of hsp27 in cultured bones and cells implicates this protein as a determinant of osteoblastic cell fate in vivo.