• 한국작물학회:학술대회논문집
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• 한국작물학회 2017년도 9th Asian Crop Science Association conference
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• pp.97-97
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• 2017

Plant genomes include heterochromatic loci that consist of repetitive sequences and transposable elements. LTR retrotransposon is the major class of transposons in advanced plants in terms of proportion in plant genome. The elements contribute not only to genome size but also to genome stability and gene expression. A number of cases have been reported transposon insertions near genic regions affect crop traits such as fruit pigments, stress tolerance, and yields. Functional LTR retrotransposons produce extrachromosomal DNA from genomic RNA by reverse transcription that takes place within virus-like-particles (VLPs). DECREASED DNA METHYLATION 1 (DDM1) plays important roles in maintaining DNA methylation of heterochromatin affecting all sequence contexts, CG, CHG, and CHH. Previous studies showed that ddm1 mutant exhibits massive transcription of retrotransposons in Arabidopsis, but only few of them were able to create new insertions into the genome. RNA-dependent RNA POLYMERASE 6 (RDR6) is known to function in restricting accumulation of transposon RNA by processing the transcripts into 21-22 nt epigenetically activated small interfering RNA (easiRNA). We purified VLPs and sequence cDNA to identify functional LTR retrotransposons in Arabidopsis ddm1 and ddm1rdr6 plants. Over 20 LTR copia and gypsy families were detected in ddm1 and ddm1rdr6 sequencing libraries and most of them were not reported for mobility. In ddm1rdr6, short fragments of ATHILA gypsy elements were detected. It suggests easiRNAs might regulate reverse transcription steps. The highest enriched element among transposon loci was previously characterized EVADE element. It has been reported that active EVADE element is more efficiently silenced through female germline than male germline. By genetic analyses, we found ddm1 and rdr6 mutation affect maternal silencing of active EVADE elements. DDM1-GFP protein accumulated in megaspore mother cell but was not found in mature egg cell. The fusion protein was also found in early embryo and maternal DDM1-GFP allele was more dominantly expressed in the embryo. We observed localization of DDM1-GFP in Arabidopsis and DDM1-YFP in maize and found the proteins accumulated in dividing zone of root tips. Currently we are looking at cell cycle dependency of DDM1 expression using maize system. Among 10 AGO proteins in Arabidopsis, AGO9 is specifically expressed in egg cell and shoot meristematic cells. In addition, mutation of AGO9 and RDR6 caused failure in maternal silencing, implying 21-22 nt easiRNA pathway is important for retrotransposon silencing in female gametophyte or/and early embryo. On the other hand, canonical 24 nt sRNA-directed DNA methylation (RdDM) pathways did not contribute to maternal silencing as confirmed by this study. Heat-activated LTR retrotransposon, ONSEN, was not silenced by DDM1 but the silencing mechanisms require RdDM pathways in somatic cells. We will propose distinct mechanisms of LTR retrotransposons in germline and somatic stages.

• Asian-Australasian Journal of Animal Sciences
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• 제26권12호
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• pp.1680-1688
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• 2013

Many different approaches have been developed to improve the efficiency of animal cloning by somatic cell nuclear transfer (SCNT), one of which is to modify histone acetylation levels using histone deacetylase inhibitors (HDACi) such as trichostatin A (TSA). In the present study, we examined the effect of TSA on in vitro development of porcine embryos derived from SCNT. We found that TSA treatment (50 nM) for 24 h following oocyte activation improved blastocyst formation rates (to 22.0%) compared with 8.9% in the non-treatment group and total cell number of the blastocysts for determining embryo quality also increased significantly ($88.9{\rightarrow}114.4$). Changes in histone acetylation levels as a result of TSA treatment were examined using indirect immunofluorescence and confocal microscopy scanning. Results showed that the histone acetylation level in TSA-treated embryos was higher than that in controls at both acetylated histone H3 lysine 9 (AcH3K9) and acetylated histone H4 lysine 12 (AcH4K12). Next, we compared the expression patterns of seven genes (OCT4, ID1; the pluripotent genes, H19, NNAT, PEG1; the imprinting genes, cytokeratin 8 and 18; the trophoblast marker genes). The SCNT blastocysts both with and without TSA treatment showed lower levels of OCT4, ID1, cytokeratin 8 and 18 than those of the in vivo blastocysts. In the case of the imprinting genes H19 and NNAT, except PEG1, the SCNT blastocysts both with and without TSA treatment showed higher levels than those of the in vivo blastocysts. Although the gene expression patterns between cloned blastocysts and their in vivo counterparts were different regardless of TSA treatment, it appears that several genes in NT blastocysts after TSA treatment showed a slight tendency toward expression patterns of in vivo blastocysts. Our results suggest that TSA treatment may improve preimplantation porcine embryo development following SCNT.

• 셀메드
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• 제1권1호
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• pp.5.1-5.3
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• 2011

Molecular events that cause tumor formation enhance a number of HOX genes, called switch genes, coding for RNApolymeraseII transcription factors. Thus, in tumor cells, RNApolymeraseII is more active than in other somatic cells. Amanita phalloides contains amanitin which inhibits RNApolymeraseII. Partial inhibition with amanitin influences tumor cell - but not normal cell - activity. To widen the treatment spectrum, dilutions of Amanita phalloides, containing amanitin, are applied to a patient with mammary duct cancer. For monitoring tumormarkers, different doses of amanitin are applied. The former duplication time of tumor growth represented three months; however within a period of 18 months the patient can be stabilized without further growth of the tumor. There are also no severe symptoms, no liver damage and no continuous erythrocyte deprivation. This new principle of tumor therapy shows high potential to provide a medical treatment.

• Genomics & Informatics
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• 제21권1호
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• pp.11.1-11.5
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• 2023

Breast cancer is the most common cancer worldwide, and advanced breast cancer with metastases is incurable mainly with currently available therapies. Therefore, it is essential to understand molecular characteristics during the progression of breast carcinogenesis. Here, we report a dataset of whole genomes from the human mammary epithelial cell system derived from a reduction mammoplasty specimen. This system comprises pre-stasis 184D cells, considered normal, and seven cell lines along cancer progression series that are immortalized or additionally acquired anchorage-independent growth. Our analysis of the whole-genome sequencing (WGS) data indicates that those seven cancer progression series cells have somatic mutations whose number ranges from 8,393 to 39,564 (with an average of 30,591) compared to 184D cells. These WGS data and our mutation analysis will provide helpful information to identify driver mutations and elucidate molecular mechanisms for breast carcinogenesis.

• Journal of Plant Biotechnology
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• 제40권3호
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• pp.141-146
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• 2013

본 연구는 낙엽송 배발생세포의 배양기간에 따른 현탁세포의 생장, 체세포배 유도 및 발아를 위한 다양한 삼투압제 종류 및 농도 효과를 조사하기 위해 수행되었다. 배발생 현탁세포의 생장은 배양일수가 증가함에 따라 settled cells volume (SCV)가 지속적으로 증가하는 경향을 보여 배양 18일 경에는 최대 10.1 ml의 SCV를 보였고, 그 이후로는 세포생장이 감소하였다. 현탁세포로부터 체세포배 발생을 위한 삼투압제 종류 및 농도에 따른 효과 비교에서 최대의 체세포배 유도 수는 0.2 M sucrose 처리구에서 352.3개(/g FW)로 나타났으며, 0.2 M maltose (203.7) 및 0.3 M maltose (193.7) 처리구에서 또한 효과가 있었다. 그러나 7.5% polyethylene glycol (PEG)이 첨가된 0.15 M sucrose 혹은 maltose 각각의 처리구에서는 체세포배 발생이 전혀 이루어지지 않았다. 다양한 삼투압제 종류 및 농도에서 발생된 체세포배의 발아율 비교에서는 최대 자엽 형성율(25.2%) 0.3 M maltose, 하배축 형성률(39%), 뿌리 발생율(30.3%) 및 식물체 재분화율(3.5%)은 0.2 M sucrose 처리구에서 각각 나타났다.

• 한국작물학회지
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• 제36권4호
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• pp.310-318
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• 1991

트리티케일 품종육성의 기초자료를 제공하기 위해, 6배체 트리티케일인 신기호밀(TC)과 6배체 보통밀 5개 품종을 교잡한 잡종 초기세대의 화분 모세포와 체세포의 염색체수 변이를 검토한 시험 결과를 요약하면 다음과 같다. 1 트리티케일과 밀의 F$_1$에서 화분모세포 염색체수는 조합간 변이를 보였으며 5조합 평균으로 볼때 1가 염색체 11.9, 2가 염색체 14.4, 3가 염색체 0.44개였다. 2 트리티케일과 밀의 F$_1$ 화분 임성과 교잡률 (F$_1$, F$_2$, F$_1$/P$_2$), 화분임성과 염색체수, 2가 염색체수와 교잡률(F$_1$, F$_2$, F$_1$/P$_2$)간에는 정의 상관관계가, F$_1$ 화분 임성 및 교잡률과 1가 염색체및 3가 염색체수와는 각각 부의 상관관계가 있었다. 3. 체세포 염색체수는 F$_1$은 42개였고 F$_2$와 F$_1$/P$_2$은 고이수체(42개 이상)빈도가, F$_1$/P$_2$은 저이수체(42개 이하)의 빈도가 높았다. 4. 이하의 결과는 트리티케일과 밀을 교배하여 얻은 F$_2$나 여교잡세대에서의 체세포 염색체수 구성이 Random이 아님을 암시하고 있다.

• 한국동물학회지
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• 제26권2호
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• pp.107-123
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• 1983

The globus pallidus of normal cats were prepared for electron microscopic study following perfusion with a mixture of 1% paraformaldehyde and 1% glutaraldehyde solution. Neurons of two size categories were identified in 1 $\\mu$m araldite sections and their ultrastructural characteristics were studied in adjacent thin section. 1. Large neurons ($30 \\mum \\times 45 \\mum$ in diameter) had extensive areas of rough surfaced endoplasmic reticulm, abundant perinuclear Golgi complex, numerous mitochondria and lipofusin granule, and had a large spherical nucleus with shallow indentation of nuclear manbrane. Small neurons ($17 \\mum \\times 27 \\mum$ in diameter) had poorly rough surfaced endoplasmic reticulum, moderate number of mitochondria and randomly distributed Golgi complex. The nuclear envelope of this cell frequently showed multiple deep invagination. 2. Three types of axo-somatic synapses were identified on the basis of the size and shape of vesicle in the axon terminal and the symmetrical or asymmetrical thickening at the synaptic site. Type I synaptic terminal shows an even distribution of round and oval synaptic vesicles, and has a symmetrical synaptic thickening. Type II axon terminals reveal mostly round and pleomorphic vesicles and a few vesicles were localized near the presynaptic membrane in pale axoplasm and its synaptic thickening were symmetric. Type III axon terminals contain round vesicles, which were aggregated in the axoplasm, and has a asymmetrical synaptic thickening. 3. The majority of axo-somatic contact with the large and small neurons were type I, and type II and III synapes were rare.

• 한국수산과학회지
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• 제42권6호
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• pp.585-590
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• 2009

The purpose of this study was to examine the effects of oral-administered sex hormone for hybrid sturgeon, bester juvenile. The bester juveniles (2 months after hatching) were received a diet containing various doses of $17\alpha$-methyltestosterone (MT) or estradiol-$17\beta$ ($E_2$) for 6 months. Somatic growth of bester sturgeon juvenile did not show significant differences between experimental and control groups (27.9-30.5 cm; 125.1-161.7 g), although survival percentages showed a decreasing tendency in MT-treated animals. By histological examination, germ cells were recorded as smooth type in MT-treated fish and uneven type of germinal epithelium in $E_2$-treated animals. Their sex ratios were 5:4:1 (male: female: undifferentiation) in control and low dose of MT-treated fish (1 mg/kg), and 9:1:0 in fish treated with high dose of MT (10 mg/kg), whereas the ratios were reversed by both low and high doses of $E_2$ treatment, recorded as 2:8:0. Gonadal areas were not significantly differed in all trials (424,600.4 - 1,039,656.3 ${\mu}m^2$). Total number of germ cells, number of germ cells per gonadal areas and number of germ cells per area were significantly higher to 144.7-148.7 cells/section, 374.0-408.5 $cells/mm^2$ and 1,599.5-1,670.9 $cells/mm^2$ in $E_2$ treatment than those of others (30.4-63.9 cells/section, 148.4-226.9 $cells/mm^2$ and 850.0-1,050.6 $cells/mm^2$), respectively. And somatic growth according to their gender was not significantly differed between male and female.

• International Journal of Stem Cells
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• 제17권2호
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• pp.194-203
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• 2024

Evaluating cell metabolism is crucial during pluripotent stem cell (PSC) differentiation and somatic cell reprogramming as it affects cell fate. As cultured stem cells are heterogeneous, a comparative analysis of relative metabolism using existing metabolic analysis methods is difficult, resulting in inaccuracies. In this study, we measured human PSC basal metabolic levels using a Seahorse analyzer. We used fibroblasts, human induced PSCs, and human embryonic stem cells to monitor changes in basal metabolic levels according to cell number and determine the number of cells suitable for analysis. We evaluated normalization methods using glucose and selected the most suitable for the metabolic analysis of heterogeneous PSCs during the reprogramming stage. The response of fibroblasts to glucose increased with starvation time, with oxygen consumption rate and extracellular acidification rate responding most effectively to glucose 4 hours after starvation and declining after 5 hours of starvation. Fibroblasts and PSCs achieved appropriate responses to glucose without damaging their metabolism 2~4 and 2~3 hours after starvation, respectively. We developed a novel method for comparing basal metabolic rates of fibroblasts and PSCs, focusing on quantitative analysis of glycolysis and oxidative phosphorylation using glucose without enzyme inhibitors. This protocol enables efficient comparison of energy metabolism among cell types, including undifferentiated PSCs, differentiated cells, and cells undergoing cellular reprogramming, and addresses critical issues, such as differences in basal metabolic levels and sensitivity to normalization, providing valuable insights into cellular energetics.

• Journal of Plant Biotechnology
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• 제44권3호
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• pp.320-324
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• 2017

현대적인 농업기계발달과 그에 따른 집약농업 발달은 토양압축을 야기하고 뿌리에 압박 스트레스를 가하여 생육을 저하시킨다. 뿌리에 압박스트레스를 작용하여 식물 생장발육에 영향과 생식의 변화 양상을 연구하기 위해 Kalanchoe pinnata를 사용하였다. K. pinnata는 잎의 가장자리에서 무성생식이 가능한 체세포 배를 형성하는 것으로 알려져 왔다. Kalanchoe pinnata의 뿌리 압박 효과를 고농도 agar 농도를 사용하여 외부 스트레스 요인에 따른 체세포 배 형성 및 기관분화 경향의 변화를 관찰하고 이러한 현상을 조직학적으로 연구 하였다. 스트레스 요인으로 배양배지에서 agar의 농도를 0.5%에서 1.5%까지의 범위로 조성하여 뿌리에 압박효과를 야기하였고, 이후 K. pinnata의 줄기와 잎 등을 microtechnique 방법으로 조직의 변화를 연구하였다. In vivo에서 K. pinnata는 수분부족 및 과도한 광조건에 의해 잎 가장자리에서 $2^{nd}$, $3^{rd}$ plantlet이 생성이 되는 것을 확인하였다. 기내배양 연구에서 agar의 농도가 낮을수록 개체 수의 증가 및 생체량의 증가가 빠르지만 잎 만곡부에서 plantlet의 발생은 나타나지 않는 경향을 나타냈다. 반면에 agar의 농도가 증가할수록 개체수의 증가가 낮은 경향을 나타났다. 또한 agar 1.5%의 배지에서만 잎에서 plantlet 발생현상이 나타났다. Agar 농도의 차이는 K. pinnata의 뿌리에 스트레스 요인으로 작용하여 무성생식의 양상이 뿌리에서 포기 나누기 방법에서 잎에서 소식물체 형성으로 변화하는 경향을 나타났다. 이는 뿌리 압박 효과가 스트레스로 작용하여 식물 생식 양상을 변화 시킬 수 있게 되는 것으로 사료된다.