• International journal of advanced smart convergence
• /
• v.7 no.1
• /
• pp.48-63
• /
• 2018

The combination of Simian Virus40 (SV40)'s large T antigen with its replication origin is commonly used in molecular studies to enhance the expression of heterogeneous genes through multiplying the plasmid copy number. There are no reports related to the impact of the SV40 T antigen on plant, multiple fissional, cell-type. This study explores the response of two multiple-fission microalgal cells, Scenedesmus quadricauda and Chlorella vulgaris, to the expression of the T-antigen, with aim of applying SV40 T-antigen to increase the expression efficiency of foreign genes in the two species. Different levels of low-expression have been constructed to control the expression of SV40 T antigen using three heterogenous promoters (NOS, CaMV35S, and CMV). Chlorella cultures showed slowdown in the growth rate for samples harboring the T antigen under the control of CaMV35S and CMV promoters, unlike Scenedesmus cultures which showed no significant difference between samples and could have silenced the expression.

• Biomedical Science Letters
• /
• v.10 no.2
• /
• pp.85-92
• /
• 2004

Immortalization of primary corneal cells has influence on pharmacy, medical and biological fields. Especially, investigation of immortalization mechanism using viral oncoproteins is useful for medical treatments, and these cell lines will be useful materials for toxic test of medical supplies and cell biological experiments. Rabbit corneal fibroblasts in culture undergo a finite number of divisions before they reach a terminally non-proliferating state known as replicative senescence. Therefore, we attempted to induce immortalization of rabbit corneal fibroblasts with SV 40 large T antigen. As a result of experiment, expression of SV 40 large T antigen was confirmed, and expression of proteins related to cell cycle repressor was decreased in the transfection group compared with non-transfection group. According to the results of cell cycle phase distribution test, SV 40 large T antigen-transfected cells had obtained higher proliferation rate than primary cells. It was confirmed that during induction of immortalization, SV 40 large T antigen was not able to increase telomerase activity. In conclusion, we made a rabbit corneal fibroblast cell line with SV40 large T antigen. This cell line will be useful for further studies of mammalian fibroblast biology, particularly with regard to angiogenesis and malignant transformation. In addition, this cell line offers opportunity for testing potential therapeutics and can be used for toxicity tests of materials or cosmetics. In the future, our cell line can potentially be utilized in a wide range of biology related fields.

• Proceedings of the KSAR Conference
• /
• 2001.03a
• /
• pp.47-47
• /
• 2001

The neuropeptide vasopressin (VP) is a nine- amino acid hormone synthesized as preprohormone in the cell bodies of hypothalamic magnocellular neurons. The tumor in magnocellular neurons of the hypothalamus is associated with disfunctions of the cell bodies, leading to the diabetes insipidus. In order to study with the diabetes insipidus caused by a defect in VP synthesis and its secretion, we have produced the transgenic mice regulated by vasopressin promoter inserted to SV40 T antigen coding sequence (pVPSV.IGR2.1). One transgenic line expressing high levels of SV40 T antigen was propagated. The founder and all transgene positive adult animals have appeared with shorten mortality or apparent phenotypic abnormalities, including immune complex disease, and eventually die between 4 and 8 months of age. The mRNA and protein of SV40T antigen transgene were detected in brain of fetus as well as in brain, spleen, lung and lymph node in moribund at the age of 20 weeks. Histological analysis of transgenic mice showed that tumor developed in brain similar to primitive neuroectodermal tumors (PNET) in man. We also detected lymphomas in spleen and lymph node, and consequent tumor formation in various tissues of the transgenic mice. In pVPSV.IGR2.1, 21% mice showed brain tumor (PNET) at 5 weeks and 100% mice showed brain tumor after 15 weeks. In addition, Expression of apoptosis related genes (Bcl-28 & Bax) was increased over their age in mice with PNET as compared to control mice. Apoptosis related gene expression might be deregulated in mice with brain tumor. However, transgenic mice were not developed with the diabetes insipidus. These mice represent the first disease model to exhibit primitive neuroectodermal tumor in brain, as well as a unique model system for exploring the cellular pathogenesis of lymphomas.

• The Korean Journal of Zoology
• /
• v.17 no.2
• /
• pp.51-56
• /
• 1974

Newborn Armenian and Chinese hamsters inoculated with adenovirus type 12 developed undifferentiated small cell tumors as early as 27 days after inoculation in the Chinese hamsters and within 30$\\sim$45 days in the Armenian hamsters. These tumors were transplantable and epithelial-like cell in morphology. Cultures of 6 tumors underwent spontaneous reversion to fibroblast-like morphology during the 14$\\sim$20 in vitro passages in the absence of chromosomal disturbances. While epithelial-like tumor derivatives were oncogenic and positive for the T-antigen, fibroblast-like revertants were non-oncogenic and negative for the T-antigen. Two other tumor derivatives reverted to fibroblast-like forms, immediately following exposure to SV40. These lacked the adenovirus T-antigen but were positive for the SV40 T-antigen and formed sarcomas in animals.

• The Korean Journal of Zoology
• /
• v.28 no.3
• /
• pp.166-178
• /
• 1985

In order to express hepatitis B surface antigen $(HB_sAg)$ containing pre-surface antigen region in mammalian calls, 2.7 kb DNA fragment containing pre-surface region-$HB_sAg$ gene poly(A) addition site of HBV genome was cloned into simian virus 40(SV 40) based chimeric vector pSVOB. 2.7 kb DNA fragment was derived from pHBVD 107 containing tandem copies of the HBV genome in a head-to-tail arrangement by Bgl II digestion. Construction of the vector pSVOE involved the incorporation of SV40 sequences spanning the viral origin of replication and 72 bp repeats (enhancer) into a pBR 322 derivative lacking sequences which inhibit replication in mammalian cells. Bam HI linker was inserted at the Pvu II site in the proximity of SV40 late promoter of pSVOE and named as pSVOB. To construct the recombinant plasmid pSVBS, pHBVD 107 was digested with Bgl II to isolate 2.7kb DNA fragment and the fragment was ligated into the Bam HI site of pSVOB by ligation. Preliminary result showed that the recombinant plasmid pSVBS produced $HB_sAg$ in the monkey cell producing large T antigen (COS cell).

• Applied Biological Chemistry
• /
• v.44 no.4
• /
• pp.211-214
• /
• 2001

Utilizing the foreign gene expression system of Drosophila melanogaster Schneider line 2(S2) cell, the degree of transient protein and mRNA expression was examined with different terminators. In the case of transient expression, the expression level of green fluorescent protein(GFP) was the highest when the transfection agent was eliminated and then cultivated for 36 to 48 hr. The terminators(SV40 p(A), SV40 small T-antigen and human gastrin 3'UTR) of the expression vector system were each cloned with endostatin; thereafter, the expression levels of the endostatin and its mRNA were compared. When the expression levels of endostatin were compared 36 hr after transfection, the SV40 p(A) terminator showed the highest expression level of endostatin and its mRNA.

• The Korean Journal of Zoology
• /
• v.31 no.1
• /
• pp.49-55
• /
• 1988

A few SV4O-transformed human cells such as SV8O are potentially tumorigenic but rejected by athymic hosts. However, one cell line in this group (W118IVA-2) is known to be fully tumorigenic. Two clones were obtained after the injection of W118IVA-2, of which NW1SC1-1 was tumorigenic but NW18C1-2 was not in nude mice. As examined by Southern blot analysis, NW18C1-1 appears to contain more copy number of SV40 sequences than NW18C1-2 does. However, it was unable to demonstrate that this difference elicits the tumorigenicity in NW18C1-1 but not in NW18C1-2. Therefore, the latter clone was tested if it expresses SV40 early genes to produce large T as well as small t antigens using indirect immunofluorescent assay and immunoprecipitation. In addition, mouse NIH3T3 cells were transfected with the cellular DNA of NW1SC1-2 as well as that of NW18C1-1 to examine if the viral genomes in the clones can make the nontransformed cells to acquire malignant growth potential in vivo. The transformed cells expressed large T antigen and became tumorigenic. Thus, the transforming functions of NW1SC1-2 cell appers to be intact. These results clearly suggest that the inability of NW18C1-2 cell to form tumor in nude mice is not because they are inherently nontumorigenic. However, the possibility that the interaction of SV40 with its host differs in these clones can not he ruled out.

• BMB Reports
• /
• v.28 no.4
• /
• pp.331-335
• /
• 1995

Simian virus 40 (SV40) small-t antigen (small-t) has been known to regulate the activity of a cellular enzyme, protein phosphatase 2A (PP2A), composed of A. B, and C subunits, via binding to the A subunit In the study presented here, the stoichiometry of the binding of small-t to PP2A was determined to be 1: 1. It was also shown that small-t binds to the AC form of PP2A with a higher apparent affinity than it binds to the free A subunit. We also characterized the interaction of PP2A with wild-type and various mutant small-ts. A single-point mutant (Val134Met) and a double-point mutant (Trp147Gly;Leu152 Pro) of small-t exhibited 3-fold and 5-fold lower potencies in inhibiting PP2A activity. respectively. This suggests that the region around amino acids between 134 and 152 of small-t might be important in regulating the enzyme activity of PP2A.

• Molecules and Cells
• /
• v.37 no.7
• /
• pp.562-567
• /
• 2014

Human Hertwig's epithelial root sheath/epithelial rests of Malassez (HERS/ERM) cells are epithelial remnants of teeth residing in the periodontium. Although the functional roles of HERS/ERM cells have yet to be elucidated, they are a unique epithelial cell population in adult teeth and are reported to have stem cell characteristics. Therefore, HERS/ERM cells might play a role as an epithelial component for the repair or regeneration of dental hard tissues; however, they are very rare population in periodontium and the primary isolation of them is considered to be difficult. To overcome these problems, we immortalized primary HERS/ERM cells isolated from human periodontium using SV40 large T antigen (SV40 LT) and performed a characterization of the immortalized cell line. Primary HERS/ERM cells could not be maintained for more than 6 passages; however, immortalized HERS/ERM cells were maintained for more than 20 passages. There were no differences in the morphological and immunophenotypic characteristics of HERS/ERM cells and immortalized HERS/ERM cells. The expression of epithelial stem cell and embryonic stem cell markers was maintained in immortalized HERS/ERM cells. Moreover, immortalized HERS/ERM cells could acquire mesenchymal phenotypes through the epithelial-mesenchymal transition via TGF-${\beta}1$. In conclusion, we established an immortalized human HERS/ERM cell line with SV40 LT and expect this cell line to contribute to the understanding of the functional roles of HERS/ERM cells and the tissue engineering of teeth.

• Clinical and Experimental Reproductive Medicine
• /
• v.30 no.4
• /
• pp.317-324
• /
• 2003

목 적: 본 실험의 목적은 자궁내막세포를 분리 및 배양법 확립과 함께 불멸화 시키는 것이다. 방 법: 자궁내막에서 상피세포(epithelial cells)와 기질세포(stromal cells)의 분리는 Satyawaroop 등(1979)의 방법에 기초를 두었다. 자궁내막에서 상피세포와 기질세포의 순수 분리도를 확인하고, 불멸화된 기질세포에서 SV40 large T antigen을 확인하기 위하여 면역형광 염색(immunocytochemistry)과 Western blot 기법을 이용하였다. 정상 기질세포의 경우 subconfluence (60%) 상태에서 transfection을 진행하였다. 순수 분리된 plasmid DNA와 Qiagen 사의 superfect를 이용하여 transfection을 실시하였다. 결 과: 본 연구에서 우리는 두 가지 형태의 자궁내막 세포의 분리 및 배양에 성공하였다. 상피세포는 다면체의 형태를 띠며, 선(grandular)조직의 조각으로부터 나선형으로 자란다.기질 세포는 길쭉한 형태를 띠며, 상피세포에 비해 오래 살고, 빠르게 증식하여 나란한 형태로 배열된 세포 다발(cell bundle)을 형성한다. 이렇게 분리된 세포들은 95%의 균질성을 보였으며, 면역형광염색과 western blot을 통해 확인 하였다. 한편 SV40(Simian Virus 40) large T 항원을 암호화 하고 있는 염기 서열을 포함한 플라스미드 벡터로 안정적인 트랜스펙션을 시킴으로써 불멸화 된 자궁내막의 기질 세포주를 확립하였다. 불멸화 된 세포는 그 세포가 유래한 정상의 세포와 동일한 표현형을 가지고 있었다. 결 론: 본 연구에서, 우리는 자궁내막에서 상피세포(epithelial cells)과 기질세포(stromal cells)를 분리하여 배양법을 확립하였다. 동시에 SV40 large T antigen을 이용하여 불멸화된 세포주를 확립하였다. 이렇게 확립된 세포주는 자궁의 생리작용 연구 및 자궁내막증(Endometriosis)과 자궁암(Endometrial cancer) 등과 같은 여러 자궁관련 질병 연구에 많은 도움이 될 것으로 사료된다.