• Clinical and Experimental Reproductive Medicine
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• v.37 no.1
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• pp.13-23
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• 2010

Objective: The present study was carried out to induce differentiation of human embryonic stem cells (hESCs) into germ cells and to establish a culture condition for single hESCs dissociated by enzyme. Methods: Embryonic body (EB) was formed by hanging drop culture for 3 days from hESCs colony. The EBs were cultured in the medium supplemented with retionic acid (RA) or/and bone morphogenetic protein-4 (BMP4) for 14 days to differentiate into germ cells. Germ cell specific markers, c-kit and VASA were used for immunohistochemistry of EB. Human ESCs colonies were dissociated into single cells by Collagenase, Tryple and Accutase, and then colony formation rate of the single cells was examined. Rho-associated kinase inhibitor (ROCK inhibitor, Y27632) was added into the culture medium of single cells to reduce the apoptotic damage during the dissociation. Results: Single cells dissociated with Tryple or Accutase showed higher colony formation rates compared to the cells dissociated with Collagenase. Seeding of $5{\times}10^3$ cells/well (4 well dish) was efficient to obtain high colony formation rate compared to other concentrations of seeding cell. Addition of Y27632 significantly increased the colony formation rate of the single cells dissociated by Tryple. Immunohistochemistry of EB with c-kit and VASA markers showed a weak fluorescence signals compared to the signals from the testicular tissue. Conclusion: Dissociation with Tryple was useful to obtain healthy single cells and addition of Y27632 was beneficial for survival and colony formation of the single cells. Unlike other studies, we just observed a dim fluorescence staining of the germ cell markers, probably caused by the short-term culture for the differentiation of EB compared to other studies.

• Journal of Industrial Convergence
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• v.17 no.4
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• pp.39-43
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• 2019

Mouse embryonic stem cell could show an substitutional materials of cells of neuron differentiation, positively increasing their effectiveness in the treatment of nervous symptom. We examined that mouse embryonic stem cells (mESCs) can be induced to undergo neuronal differentiation. After neuronal induction, the phenotype of mESCs changed towards neuronal morphology and mESCs were injected into the lateral ventricle of the experimental animal brain. Transplanted cells migrated to various parts of the brain and ischemic brain injury by middle cerebral artery occlusion (MCAO) increased their migration to the injured cortex. Intracerebral grafting of mESCs mostly improve sensory and motor nervous system of neurological injury in focal cerebral rats.

• 대한생식의학회:학술대회논문집
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• 2005.06a
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• pp.129-129
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• 2005

• Clinical and Experimental Reproductive Medicine
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• v.36 no.3
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• pp.143-150
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• 2009

• 대한생식의학회:학술대회논문집
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• 2003.12a
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• pp.153.2-154
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• 2003

• Clinical and Experimental Reproductive Medicine
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• v.37 no.2
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• pp.99-113
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• 2010

Objective: It has been recently reported that very small stem cells with pluripotency are detected in murine and human. The purposes of this study are to confirm whether very small putative stem cells (VSPSCs), which have the proper characteristics of stem cells as well as the expression of stem cell markers, are detected in human endometrium. Methods: The endometrial cells of 5 women, which were obtained by endometrial biopsy, were cultured for 2 weeks and were confirmed for the expressions of alkaline phosphatase, OCT-4 and CXCR4 by immunochemistry. Subsequently VSPSCs were separated by percoll density gradient method and were cultured. Also VSPSCs and their derived cells were confirmed for the expressions of OCT-4 and CXCR4. Results: The colonies, which is composed with VSPSCs less than 3 ${\mu}m$ and the 5~15 ${\mu}m$ sized hyperchromatic round cells, were detected in the endometrium of all of women and showed the strong expressions of alkaline phosphatase, OCT-4 and CXCR4. In culture after the separation of VSPSCs by percoll, these cells showed the morphological and functional characteristics of stem cells; self-renewal, colony formation, embryoid body-like formation and differential plasticity. VSPSCs formed gradually the 5~15 ${\mu}m$ sized hyperchromatic round cells and the 10~20 ${\mu}m$ sized sphere-shaped cells by cell-to-cell aggregation or cell fusion. Then these cells differentiated the various cells including fibroblast-like cells, nerve-like cells and endothelium-like cells. VSPSCs and their derived cells often showed the strong expressions of OCT-4 and CXCR4. Conclusion: VSPSCs less than 3 ${\mu}m$ and their derived cells are detected in human endometrium and these cells have the proper characteristics of stem cells and the expressions of stem cell markers as alkaline phosphatase, OCT-4 and CXCR4.

• 대한생식의학회:학술대회논문집
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• 2004.06a
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• pp.87-87
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• 2004

• Development and Reproduction
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• v.14 no.2
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• pp.123-129
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• 2010

Embryonic stem (ES) cells can self-renew maintaining the undifferentiated state. Self-renewal requires many factors such as OCT4, SOX2, and NANOG. It is previously known that OCT4 and SOX2 can bind to NANOG promoter and support Nanog gene expression in mouse ES cells by the detailed studies using the mouse Nanog promoter. Here, we constructed serial deletion mutant promoter-reporter constructs to investigate the human Nanog gene promoter in detail. The highest promoter activity was obtained in the 0.6 kb (-253/+365) promoter-reporter construct which includes the binding sites of OCT4 and SOX2. To further confirm contribution of OCT4 and SOX2 in Nanog gene expression, we introduced site- directed mutation(s) in the OCT4 and/or SOX2 binding sites of the human Nanog promoter 0.6 kb (-253/+365) and checked the influence of the mutation on the promoter activity using human EC cell line NCCIT. Mutation either in OCT4 binding site or SOX2 binding site significantly reduced the activity of Nanog promoter which directly confirmed that OCT4 and SOX2 binding is essential in human Nanog gene expression.

• Development and Reproduction
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• v.14 no.4
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• pp.243-251
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• 2010

ESRRB (Estrogen related receptor $\beta$) is an orphan receptor, and have a role on maintaining the undifferentiated state and self-renewal of pluripotent stem cell as a transcription factor which regulates the expression of OCT4 and NANOG genes. Also, Feng et al. (2009) reported that Esrrb, Oct4 and Sox2 could induce pluripotent stem cell from somatic cells. The aim of the present study was to develop the direct delivery system of human ESRRB protein into human amniotic fluid-derived stem cells (AFSCs) and to analyze the effect of ESRRB on the regulation of pluripotency-related genes. Human ESRRB has three isoforms arisen by alternative splicing. We cloned short-form ESRRB and made a fusion protein of ESRRB and R7 for an efficient protein transfer to cell. R7 as cell-penetrating peptide(CPP) can help to transfer ESRRB into cells. R7-ESRRB-His6 protein was observed in the cytoplasm and nuclei within 5 hours after treatment. Also, we could observe R7-ESRRB-His6 protein only in the nuclei within 24 hours. Realtime PCR showed that ESRRB increased expression of OCT4 and NANOG as well as SOX2 gene. Therefore, we demonstrated that R7-ESRRB-His6 proteins were efficiently transferred into the nuclei of AFSCs and work well as a possible transcription factor.

• Journal of Life Science
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• v.19 no.4
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• pp.549-552
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• 2009

Genetic mutations by gene fusion result from chromosomal rearrangement, trans-splicing, and intergenic splicing. Trans-splicing is a phenomenon in which two pre-mRNAs grow together into one. We analyzed the trans-splicing products in embryonic stem cells. By using bioinformatic tools, 70 trans-splicing transcripts were identified. They are classified into 6 types according to fusion pattern: 5'UTR-5'UTR, 5'UTR-3'UTR, 3'UTR-3'UTR, 5'UTR-CDS, 3'UTR-CDS, CDS-CDS. The fusion products are more abundant in CDS regions than in UTR regions, which contain multiple intron numbers. Chromosome analysis showing gene fusion via trans-splicing indicated that chromosomes 17 and 19 were activated. These data are of great use for further studies in relation to fusion genes and human diseases.