• 한국미생물·생명공학회지
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• 제35권3호
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• pp.184-190
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• 2007

대략 2 kb의 크기를 가진 Pichia pastoris phosphoglycerate kinase gene (PGK1)의 프로모터부분을 266bp의 작은 크기로 최소화하여 P. pastoris에 있어 episomal의 새로운 항시적 발현벡터를 제조하였다. P. pastoris의 새로운 항시적 발현벡터를 개발하기 위하여 기존의 Pichia발현벡터인 pGABZB의 GAP프로모터부분을 연속적으로 일정 부분이 절단된 PGK1프로모터에 beta-galactosidase유전자가 결합된 부분으로 치환하였다. LacZ유전자를 reporter유전자로 사용하였을 때에 PGK1프로모터의 발현세기는 다른 항시적 프로모터인 GAP프로모터 보다는 낮았지만 TEF1프로모터 보다는 높았다. 본 논문에서 PGK1 프로모터의 불필요한 부분을 제거함으로서 Pichia에서 외래발현을 위한 새로운 episomal발현벡터인 pPGKZ-E를 제조하였으며 이 것은 P. pastoris에 있어 발현세기를 선택할 수 있는 발현벡터선택의 폭을 넓게 하였다.

• Journal of Microbiology and Biotechnology
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• 제16권9호
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• pp.1362-1368
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• 2006

A new constitutive episomal expression vector, pGAPZ-E, was constructed and used for initial screening of eukaryotic target gene expression in Pichia pastoris. Two reporter genes such as beta-galactosidase gene and GFPuv gene were overexpressed in P. pastoris. The expression level of the episomal pGAPZ-E strain was higher than that of the integrated form when the beta-galactosidase gene was used as the reporter gene in P. pastoris X33. The avoiding of both the integration procedure and an induction step simplified the overall screening process for eukaryotic target gene expression in P. pastoris. Nine human protein targets from the Core 50, family of Northeast Structural Genomics Consortium (http://www.nesg.org), which were intractable when expressed in E. coli, were subjected to rapid screening for soluble expression in P. pastoris. HR547, HR919, and HR1697 human proteins, which had previously been found to express poorly or to be insoluble in E. coli, expressed in soluble form in P. pastoris. Therefore, the new episomal GAP promoter vector provides a convenient and alternative system for high-throughput screening of eukaryotic protein expression in P. pastoris.

• Parasites, Hosts and Diseases
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• 제49권4호
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• pp.357-364
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• 2011

Various Leishmania species were engineered with green fluorescent protein (GFP) using episomal vectors that encoded an antibiotic resistance gene, such as aminoglycoside geneticin sulphate (G418). Most reports of GFP-Leishmania have used the flagellated extracellular promastigote, the stage of parasite detected in the midgut of the sandfly vector; fewer studies have been performed with amastigotes, the stage of parasite detected in mammals. In this study, comparisons were made regarding the efficiency for in vitro G418 selection of GFP-Leishmania amazonensis promastigotes and amastigotes and the use of in vivo G418 selection. The GFP-promastigotes retained episomal plasmid for a prolonged period and G418 treatment was necessary and efficient for in vitro selection. In contrast, GFP-amastigotes showed low retention of the episomal plasmid in the absence of G418 selection and low sensitivity to antibiotics in vitro. The use of protocols for G418 selection using infected BALB/c mice also indicated low sensitivity to antibiotics against amastigotes in cutaneous lesions.

• Journal of Microbiology and Biotechnology
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• 제31권12호
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• pp.1722-1731
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• 2021

The genus Streptomyces is intensively studied due to its excellent ability to produce secondary metabolites with diverse bioactivities. In particular, adequate precursors of secondary metabolites as well as sophisticated post modification systems make some high-yield industrial strains of Streptomyces the promising chassis for the heterologous production of natural products. However, lack of efficient genetic tools for the manipulation of industrial strains, especially the episomal vector independent tools suitable for large DNA fragment deletion, makes it difficult to remold the metabolic pathways and streamline the genomes in these strains. In this respect, we developed an efficient deletion system independent of the episomal vector for large DNA fragment deletion. Based on this system, four large segments of DNA, ranging in length from 10 kb to 200 kb, were knocked out successfully from three industrial Streptomyces strains without any marker left. Notably, compared to the classical deletion system used in Streptomyces, this deletion system takes about 25% less time in our cases. This work provides a very effective tool for further genetic engineering of the industrial Streptomyces.

• International Journal of Stem Cells
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• 제16권1호
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• pp.36-43
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• 2023

Background and Objectives: Lymphoblastoid cell lines (LCLs) deposited from disease-affected individuals could be a valuable donor cell source for generating disease-specific induced pluripotent stem cells (iPSCs). However, generation of iPSCs from the LCLs is still challenging, as yet no effective gene delivery strategy has been developed. Methods and Results: Here, we reveal an effective gene delivery method specifically for LCLs. We found that LCLs appear to be refractory toward retroviral and lentiviral transduction. Consequently, lentiviral and retroviral transduction of OCT4, SOX2, KFL4 and c-MYC into LCLs does not elicit iPSC colony formation. Interestingly, however we found that transfection of oriP/EBNA-1-based episomal vectors by electroporation is an efficient gene delivery system into LCLs, enabling iPSC generation from LCLs. These iPSCs expressed pluripotency makers (OCT4, NANOG, SSEA4, SALL4) and could form embryoid bodies. Conclusions: Our data show that electroporation is an effective gene delivery method with which LCLs can be efficiently reprogrammed into iPSCs.

• 한국양식학회지
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• 제13권1호
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• pp.29-37
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• 2000

In previously study we isolated several fish matrix attachment regions (MARs) capable of replicating the plasmid by itself. In this study we construct a fish expression vector pBaEGFP(+) containing mud loach ${\beta}$-actin promoter EGFP as reporter gene and SV40 signal. To analyze the effects of the fish expression vector respectively. The fish ARS containing constructs pBaEGFP(+)-ARSs were transfected cells with pBaEGFP(+)-ARS101 and pBaEGFP(+)-ARS223 reduced 10 days to 25 days and then was constant to 30 days after transfection while that of the control vector without ARS element was basal level. The intensity of both constructs showed about 30fold of the intensity compared with the control vector on 30days after transfection individually .E. coli back-transformation analysis shows that pBaEGFP(+)-ARS223 and pBaEGFP(+)-ARS905 maintain in episomal state at least 30 days after transfection. The result indicates that both may be able to replicate the vector in BF-2 cell. Therefore the matrix-attached ARSs enhancing expression of the reporter gene might be useful as a component o the expression vector for transgenic studies.

• 미생물학회지
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• 제32권4호
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• pp.271-279
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• 1994

${\alpha}$-Amylase와 glucoamylase를 동시에 안정하게 분비하여 전분을 일단계로 직접 에탄올로 발효시킬수 있는 효모 균주를 개발하기 위하여 glucoamylase를 분비하는 Saccharomyces diastaticus hybrid 균주에 쥐의 침샘 유래의 ${\alpha}$-amylase cDNA 유전자를 plasmid vector를 이용하여 도입하였다. 이 균주로부터 효소생산에 필요한 유전자를 잃어버림이 없이 안정하게 분비할 수 있도록 하기 위하여 $\alpha$-amylase 유전자를 효모의 염색체에 삽입시키기 위한 integrating plasmid vector인 YIpMS$\Delta$R(LEU2)를 제작하였다. 이 vector의 효모형질전환에 있어 원형(circular)상태와 제한 효소 XbaI으로 처리된 직선화된(linearized) 상태의 두가지 형태를 비교한 결과 형질전환 효율에서나 형질전환체내의 $\alpha$-amylase 유전자 보유정도가 모두 직선화된 형태의 경우가 원형상태의 경우보다 높았다. Linearized vecotr를 가진 효모 형질전환체에서의 유전자 발현 안정도는 세포분열을 거듭할수록 episomal vecotr에 의한 효모 형질전환체에서의 발현 안정도보다 우수하게 나타났다. 또한 이 linearized vector를 가진 형질전환체는 $\alpha$-amylase와 glucoamylase를 동시에 분비하여 glucoamylase만 분비하는 원균주보다 2배 이상의 전분분해력을 보였다.

• Molecules and Cells
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• 제46권4호
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• pp.209-218
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• 2023

In induced pluripotent stem cells (iPSCs), pluripotency is induced artificially by introducing the transcription factors Oct4, Sox2, Klf4, and c-Myc. When a transgene is introduced using a viral vector, the transgene may be integrated into the host genome and cause a mutation and cancer. No integration occurs when an episomal vector is used, but this method has a limitation in that remnants of the virus or vector remain in the cell, which limits the use of such iPSCs in therapeutic applications. Chemical reprogramming, which relies on treatment with small-molecule compounds to induce pluripotency, can overcome this problem. In this method, reprogramming is induced according to the gene expression pattern of extra-embryonic endoderm (XEN) cells, which are used as an intermediate stage in pluripotency induction. Therefore, iPSCs can be induced only from established XEN cells. We induced XEN cells using small molecules that modulate a signaling pathway and affect epigenetic modifications, and devised a culture method which can produce homogeneous XEN cells. At least 4 passages were required to establish morphologically homogeneous chemically induced XEN (CiXEN) cells, whose properties were similar to those of XEN cells, as revealed through cellular and molecular characterization. Chemically iPSCs derived from CiXEN cells showed characteristics similar to those of mouse embryonic stem cells. Our results show that the homogeneity of CiXEN cells is critical for the efficient induction of pluripotency by chemicals.

• Biotechnology and Bioprocess Engineering:BBE
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• 제6권3호
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• pp.173-178
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• 2001

Food yeast, Saccharomyces cerevisiae, is a safe organism with a long history of use for the production of biomass rich in high quality proteins and vitamins. AmA1, a seed storage albumin from Amaranthus hypochondriacus, has a well-balanced amino acid composition and high levels of essential amino acids and offers the possibility of further improving food animal feed additives. In order to find an effective means of expressing AmA1 in yeast, the gene was cloned into an episomal shuttle vector. Four different promoters were tested: the glyceraldehyde-3-phosphate dehydrogenase promoter, galactose dehydrogenase 10 promoter, alcohol dehydrogenase II promoter, and a hybrid ADH2-GPD promoter. The recombinant AmA1 genes were then introduced into the yeast Saccharomyces cerevisiae 2805. Northern and Western blot analyses of the yeast under appropriate conditions revealed that AmA1 was expressed by all four promoters at varying levels. An enzyme-linked immunosorbent assay demonstrated that the amount of AmA1 protein in the recombinant yeast was 1.3-4.3% of the total soluble proteins. The highest expression level was obtained from the hybrid ADH2-GPD promoter.

• Reproductive and Developmental Biology
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• 제38권2호
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• pp.79-84
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• 2014

MicroRNAs (miRNAs) are approximately 22 nucleotides of small noncoding RNAs that control gene expression at the posttranscriptional level through translational inhibition and destabilization of their target mRNAs. The miRNAs are phylogenetically conserved and have been shown to be instrumental in a wide variety of key biological processes including cell cycle regulation, apoptosis, metabolism, imprinting, and differentiation. Recently, a paper has shown that expression of the miRNA-302/367 cluster expressed abundantly in mouse and human embryonic stem cells (ESCs) can directly reprogram mouse and human somatic cells to induced pluripotent stem cells (iPSCs) efficiently in the absence of any of the four factors, Oct4, Sox2, c-Myc, and Klf4. To apply this efficient method to porcine, we analyzed porcine genomic sequence containing predicted porcine miRNA-302/367 cluster through ENSEMBL database, generated a non-replicative episomal vector system including miRNA-302/367 cluster originated from porcine embryonic fibroblasts (PEF), and tried to make porcine iPSCs by transfection of the miRNA-302/367 cluster. Colonies expressing EGFP and forming compact shape were found, but they were not established as iPSC lines. Our data in this study show that pig miRNA-302/367 cluster could not satisfy requirement of PEF reprogramming conditions for pluripotency. To make pig iPSC lines by miRNA, further studies on the role of miRNAs in pluripotency and new trials of transfection with conventional reprogramming factors are needed.