• Animal Bioscience
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• 제36권12호
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• pp.1905-1917
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• 2023

Objective: Nanog homeobox (NANOG) is a core transcription factor that contributes to pluripotency along with octamer binding transcription factor-4 (OCT4) and sex determining region-Y box-2 (SOX2). It is an epiblast lineage marker in mammalian pre-implantation embryos and exhibits a species-specific expression pattern. Therefore, it is important to understand the lineage of NANOG, the trophectoderm, and the primitive endoderm in the pig embryo. Methods: A loss- and gain-of-function analysis was done to determine the role of NANOG in lineage specification in parthenogenetic porcine blastocysts. We analyzed the relationship between NANOG and pluripotent core transcription factors and other lineage makers. Results: In NANOG-null late blastocysts, OCT4-, SOX2-, and SOX17-positive cells were decreased, whereas GATA binding protein 6 (GATA6)-positive cells were increased. Quantitative real-time polymerase chain reaction revealed that the expression of SOX2 was decreased in NANOG-null blastocysts, whereas that of primitive endoderm makers, except SOX17, was increased. In NANOG-overexpressing blastocysts, caudal type homeobox 2 (CDX2-), SOX17-, and GATA6-positive cells were decreased. The results indicated that the expression of primitive endoderm markers and trophectoderm-related genes was decreased. Conclusion: Taken together, the results demonstrate that NANOG is involved in the epiblast and primitive endoderm differentiation and is essential for maintaining pluripotency within the epiblast.

• 한국가축번식학회지
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• 제21권2호
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• pp.157-165
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• 1997

포유류 배반포배의 epiblast는 내세포괴에 포함되어 있으며, 이 epiblast cells이 배 및 태아의 생식세포와 일반 체세포로 분화된다 (Beddington, 1986; Lawson 등, 1991). 그런데 조기에 발달된 부화배반포기 배가 지연발생된 부화배반포기 배보다도 많은 epiblast cells을 가지고 있다고 한다(Talbot 등, 1995). 그래서 본 연구에서는 체외수정 유래의 배반포배의 발육속도에 따른 내세포괴/영양배엽세포의 비율 및 배아간세포 확립 효율을 비교하여 발달일령 간에 차이가 있는지를 규명하고자 하였다. 공시한 소의 난포란을 TCM-199에 0.5$\mu\textrm{g}$/ml FSH, 5$\mu\textrm{g}$/ml LH, 10% FBS, 100 units/ml penicilin, 및 100$\mu\textrm{g}$/ml streptomycin을 첨가하여 39$^{\circ}C$, 5% CO2 조건하에서 24시간 동안 체외성숙한 후, 5$\mu\textrm{g}$/ml heparin으로 수정능이 획득된 1$\times$106 sperm/ml의 정자로 체외수정을 유도하였다. 체외수정 후 18~20시간에 과립막세포를 vortexing으로 제거하여 얻은 모든 체외수정란을 3mg/ml BSA, 20${\mu}\ell$/ml NEM amino acids, 40${\mu}\ell$/ml BME amino acids, 10mM glycine 및 1mM alanine이 함유된 CR1aa 배양액에서 BRL 단층세포와 공배양을 실시하였다. 수정후 7, 8 및 9일재 (체외수정일 : 0일)에 확장배반포기까지 발달한 수정란을 이중염색 및 배아간세포의 확립 실험에 공시하였다. 체외수정후 24시간에 분할된 총 1,145개의 수정란이 7, 8 및 9일째에 후기 배반포기까지 각각 222(15.6%), 103(7.2%) 및 52(3.6%)로 발달하여 총 377개 (26.4%)가 발달하였다. 내세포괴/영양배엽세포의 비율은 7일 및 8일째 배반포배에서 각각 47.2$\pm$11.9/95.1$\pm$24.4개 (33/67%) 및 40.3$\pm$12.4/83.3$\pm$26.9개 (33/67%)로서 9일째 배반포배의 19.3$\pm$8.1/62.3$\pm$23.1개 (24/76%) 보다 유의적(P<0.05)으로 높았다. ES-like cells을 확립하기 위하여 후기배반포기 배를 mouse embryonic fibroblast 단층 공배양기에 옮긴 후 5일에 내세포괴의 부착 여부를 판정하고, 10일에 배아간세포의 확립 여부를 판정하였다. 그 결과 7, 8 및 9일째의 배반포기배의 각각 47.7% (82/172), 30.9%(22/71) 및 15.6%(5/32)에서 배아간세포가 확립되었다. 이상의 결과에서 배반포기까지의 발육이 빠른 수정란에서 영양배엽에 대한 내세포괴세포의 비율이 높았고 배아간세포의 확립율도 높다는 사실을 입증할 수 있었으며, 이와 같은 결과에서 체외수정란 유래 배반포배의 질을 결정할 수 있을 것으로 생각된다.

• 한국가축번식학회지
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• 제21권2호
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• pp.167-176
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• 1997

본 연구는 수정란을 수란우에 이식하기 이전에 형질전환가능 수정란을 선발할 수 있다면 형질전환동물의 생산에 크게 도움이 되므로 3.2 kb $\beta$-actin promoter (lacZ/n대) DNA를 미세주입하여 배반포기배에서의 발현을 확인하여 이들을 선발할 수 있는가를 규명하고자 하엿다. 채란된 난포란은 10%FBS, 5$\mu\textrm{g}$/ml LH, 0.5$\mu\textrm{g}$/ml FSH, 100 unit/ml penicillin 및 100 $\mu\textrm{g}$/ml streptomycin이 함유된 TCM199에 22~24 시간동안 체외성숙을 유도후 5$\mu\textrm{g}$/ml heparin으로 수정능획득을 유도한 1$\times$106 sperm/ml의 정자로 체외수정을 시켰다. 체외수정후 18~20시간째에 vortexing에 의해 과립막세포를 제거하고 원심분리시켜 자/웅전핵이 확인되는 수정란의 핵에 3~4 ng/${\mu}\ell$ lacZ/neo DNA를 미세주입하였다. 모든 수정란의 배양은 3 mg/ml BSA, 20${\mu}\ell$/ml NEM AMINO acids 및 40${\mu}\ell$/ml BME amino acids가 함유되어 있는 CR1aa 배양액에 neo/DNA로 transfected 된 BRL 단층에서 실시하였다. G418에 대한 적정농도를 찾기 위하여 정상적인 수정란에 0, 50, 100 및 200 $\mu\textrm{g}$/ml G418를 첨가하여 배양한 결과 8일째에 30.3%(44/145), 8.7%(13/150), 0.7%(1/151) 및 0% (0/134)의 수정란이 배반포기까지 발달하였다. 그래서 본 실험에서는 일정하게 100$\mu\textrm{g}$/ml G418을 첨가하여 배양하였다. 총 1,127개의 수정란을 미세주입후 G418 없는 배양액에서 710개 (63.0%)가 분할하였다. 미세주입후 48시간째에 2-세포기이상 분할된 수정란을 대조구 및 100$\mu\textrm{g}$/ml G418처리구를 무작위로 할당하여 배양하였으며, 또한 740개의 정상수정란도 같은 반복수로 배양을 실시하였다. 미세주입한 수정란은 8일 후 11.6%(26/255) 및 5.2% (14/267)가 대조구 및 G418 처리구에서 배반포기까지 발달하였으며 정상수정란은 27.2% (151/740)가 배반포기 배까지 발달하였다. 미세주입후 대조구에서는 23.1$\pm$2.6/70.7$\pm$4.7 (32.7%)의 할구가 $\beta$-Gal 활력을 보였고, 반면에 100$\mu\textrm{g}$/ml G418 처리구에서는 40.3$\pm$4.1/48.8$\pm$7.5 (82.6%)가 $\beta$-Gal 활력을 보였다. 비록 mosaic 형태로 외래유전자가 발현되었지만 대조구에서 87.0% (26/30개) 배반포기가 $\beta$-Gal 활력을 보인 반면, G418 처리구에서는 모든 배반포기가 $\beta$-Gal 활력을 보였다 (P<0.05). 그러나 대조구 및 G418 처리구의 ICM colony에서는 영양배엽과 내배엽을 제외한 epiblast에서는 확인되지 않았다. 그러나 이 결과로부터 $\beta$-actin promoter/lacZ gene이 integration되지 않는 것인지 또는 다만 염색 확인이 되지 않는 것인지를 판단할 수는 없다. 이상의 결과는 미세주입후 G418에서 배양한 배반포기배에서는 대부분의 할구에서 주입된 gene을 발현하고 있었으나 ICM colony에서는 특히 epiblast에서는 발현되지 않거나 침묵하고 있었다. 비록 G418 처리구에서 훨씬 더 높은 비율로 주입된 gene이 발현되고 있으나 총세포수는 유의적으로 감소하여 이후 형질전환동물의 생산과 ES like-cell의 설립에는 감소될 것으로 사려된다. 그러나 형질전환 수정란의 선발 및 형질전환동물의 생산능력에 관해서는 더 많은 연구가 필요하다고 사려된다.

• Asian-Australasian Journal of Animal Sciences
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• 제7권4호
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• pp.459-466
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• 1994

Primordial germ cells (PGCs) in aves are the progenitor cells for the gametes. These cells first appear in the epiblast (Eyal-Giladi et al.. 1981). Then translocate and concentrate to endoderm of germinal crescent area in the junction of the area opaca and area pellucida lateral to the primitive streak in stage 4 through 7. They separate from the endoderm, temporarily circulate via the blood vascular system, leave the blood vessels, and finally settle down in the gonadal anlagen at stage 20-24 where they rapidly proliferate to form germ cells. Recently, several attempts have been made to introduce foreign gene into the avian genome to form a transgenic chicken. The stem cells most readily available as vehicles for genetic manipulation of germline in avian species are the PGCs. PGCs have recently been manipulated genetically and used successfully as a vector for gene transfer.

• 한국동물생명공학회지
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• 제36권4호
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• pp.175-182
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• 2021

Pluripotent stem cells could self-renew and differentiate into various cells. In particular, porcine pluripotent stem cells are useful for preclinical therapy, transgenic animals, and agricultural usage. These stem cells have naïve and primed pluripotent states. Naïve pluripotent stem cells represented by mouse embryonic stem cells form chimeras after blastocyst injection. Primed pluripotent stem cells represented by mouse epiblast stem cells and human embryonic stem cells. They could not produce chimeras after blastocyst injection. Populations of embryonic stem cells are not homogenous; therefore, reporter systems are used to clarify the status of stem cells and to isolate the cells. For this reason, studies of the OCT4 reporter system have been conducted for decades. This review will discuss the naïve and primed pluripotent states and recent progress in the development of porcine OCT4 reporter systems.

• Journal of Korean Neurosurgical Society
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• 제64권3호
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• pp.367-373
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• 2021

Secondary neurulation (SN) is a critical process to form the neural tube in the posterior region of the body including the tail. SN is distinct from the anteriorly occurring primary neurulation (PN); whereas the PN proceeds by folding an epithelial neural plate, SN precursors arise from a specified epiblast by epithelial-to-mesenchymal transition (EMT), and undergo self-renewal in the tail bud. They finally differentiate into the neural tube through mesenchymal-to-epithelial transition (MET). We here overview recent progresses in the studies of SN with a particular focus on the regulation of cell lineage, self-renewal, and EMT/MET. Cellular mechanisms underlying SN help to understand the functional diversity of the tail in vertebrates.

• 한국가축번식학회지
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• 제19권1호
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• pp.55-63
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• 1995

The putative totipotency germ cells has a relative abundance of alkaline phosphatases. Thus, histological staining of AP activity offers a new route to isolate totipotent cells and also provides insights into culture systems of these cells. Furthermore, the AP staining technique is simple and fast, requires only the napthol AS/MS substrate in combination with trapping diazonium salts such as fast red or fast blue. However, our unexpected finding was that AP staining of mouse ES cells were detected in the undifferentiaed epiblast-derived cells as well as several types of differentiating cells. This findings are different from results of Talbot et al. (1993) reported usefulness of the AP staining and implies that histological staining of AP may not by useful to determine undifferentiaed state or totipotency of ES cells. Thus, we have investigated the patterns of AP expression by RT-PCR in order to identify a marker of undifferentiated ES/primordial germ (PG) cells. In RT-PCR analysis, embryonic (E)-AP was detected only in undifferentiated ES cells, but intestinal(I)-AP was not detected in all of the examined ES and PG cells. In addition, nonspecific (NS)-AP wasdetected in undifferentiated PG cell from day 7, 5 to 13 of gestation. Histological activity of AP in ES cells was completely suppressed by addition of L-phenylalanine (Phe), L-homoarginine (Har), and L-phenylalanylglycylglycine (PheGlyGly) as an inhibitor, but RT-PCR showed the same results as in the absence of an inhibitors. Our findings suggested that expression of E-AP and NS-AP may use as a marker to determine the undifferentiated status in ES and PG cells.

• 한국가금학회지
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• 제28권1호
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• pp.69-76
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• 2001

Avian primordial germ cells (PGCs) originate from the epiblast and appear in the germinal crescent. These PGCs enter the developing blood vessels during stage 10∼12 (H&H), circulate in the blood stream, migrate into the developing gonadal anlage and differentiate into germ cells. However, it is not clear until when the migratory ability of PGC is maintained. This study was conducted to examine whether migratory ability is present in PGCs from the gonad at later embryonic developmental stages. In the present study, gonads were dissected from 5-, 6- and 10-day old quail embryos and treated with trypsin-EDTA. Gonadal PGCs (gPGCs) were purified by Ficoll-density-gradient-centrifugation and labeled with PKH26 fluorescent dye. The PKH26-labeled gPGCs were microinjected into the blood vessel of the recipient quail embryo. Manipulated recipients were incubated for 3 days, embedded in paraffin and sdctioned. The foreign gPGCs were detected by fluorescent and confocal laser microscopy. As a result, quail gPGCs, from 10, 6 and 5 day old embryos could migrate through the recipient blood stream at early stage and settle in the gonads. Thus, results suggest that gPGCs from upto 10-day old embryos keep properties seen in circulating PGC. Therefore, the PGCs of 10-day old embryonic gonads can be used for the tools of genetic manipulation.

• 한국동물생명공학회지
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• 제38권3호
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• pp.109-120
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• 2023

Background: Pluripotent stem cells (PSCs) including embryonic stem cells (ESCs) and induced pluripotent stem cells (iPSCs) offer the immense therapeutic potential in stem cell-based therapy of degenerative disorders. However, clinical trials of human ESCs cause heavy ethical concerns. With the derivation of iPSCs established by reprogramming from adult somatic cells through the transgenic expression of transcription factors, this problems would be able to overcome. In the present study, we tried to differentiate porcine iPSCs (piPSCs) into endothelial cells (ECs) for stem cell-based therapy of vascular diseases. Methods: piPSCs (OSKMNL) were induced to differentiation into ECs in four differentiation media (APEL-2, APEL-2 + 50 ng/mL of VEGF, EBM-2, EBM-2 + 50 ng/mL of VEGF) on cultured plates coated with matrigel^® (1:40 dilution with DMEM/F-12 medium) for 8 days. Differentiation efficiency of these cells were exanimated using qRT-PCR, Immunocytochemistry, Western blotting and FACS. Results: As results, expressions of pluripotency-associated markers (OCT-3/4, SOX2 and NANOG) were higher observed in all porcine differentiated cells derived from piPSCs (OSKMNL) cultured in four differentiation media than piPSCs as the control, whereas endothelial-associated marker (CD-31) in the differentiated cells was not expressed. Conclusions: It can be seen that piPSCs (OSKMNL) were not suitable to differentiate into ECs in the four differentiation media unlike porcine epiblast stem cells (pEpiSCs). Therefore, it would be required to establish a suitable PSCs for differentiating into ECs for the treatment of cardiovascular diseases.

• 한국수정란이식학회:학술대회논문집
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• 한국수정란이식학회 2002년도 국제심포지엄
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• pp.118-118
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• 2002

Programmed cell death (PCD) is thought as a well-controlled process by which unwanted cells are selectively eliminated. During the last decade many researches have elucidated molecules and their interactions involved in cell death by using largely in vitro induction of cell death or survival signals in a more defined manner, While these critical information and novel findings provide us with clearer understanding of mechanisms underlying cell death, it does by no means explain how PCD occurs and which cells or tissues are affected during normal embryonic development in vivo. In this study, we used zebrafish to examine whether the PCD is occurring selectively or randomly in developing embryos by whole mount in situ TUNEL analysis with specific markers for neural cells. The result revealed that the degree and distribution of TUNEL staining varied considerably throughout gastrulation stage, and there was also a number of TUNEL-negative embryos. Most of TUNEL-positive cells were scattered randomly throughout the blastoderm. During the gastrulation stage about 75 % of the embryos analyzed exhibited more than 5 TUNEL-positive cells. As the dorsal epiblast begins to thicken rather abruptly near the end of gastrulation, TUNEL-positive cells were mainly located along the dorsal side. Although there were some variations in TUNEL staining during segmentation and pharyngeal stages, TUNEL staining continued to be localized to the central nervous system, and was also detected in the sensory organs, trigeminal ganglions, and the primary sensory neurons. High levels of the cell death in developing brain between 20-somite and prim-6 stages are thought to play a role in the morphogenesis and organization of the brain. At prim-16 stage, cell death is considerably reduced in the brain region. Dying cells are mainly localized to the prospective brain region where ectodermal cells are about to initiate neurogenesis. As development progressed, high levels and more reproducible patterns of cell death were observed in the developing nervous system. Intensive TUNEL staining was restricted to the trigeminal ganglions, the primary sensory neurons, and sensory organs, such as olfactory pits and otic vesicles. Thus, PCD patterning in zebrafish embryos occurs randomly at early stages and becomes restricted to certain region of the embryos. The spatio-temporal pattern of PCD during the early embryonic development in zebrafish will provide basic information for further studies to elucidate genes involved in. regulation of PCD largely unknown in vivo during vertebrate embryogenesis.