• Journal of Microbiology and Biotechnology
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• 제30권11호
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• pp.1777-1784
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• 2020

To increase the availability of microalgae as producers of valuable compounds, it is necessary to develop novel systems for gene expression regulation. Among the diverse expression systems available in microalgae, none are designed to induce expression by low temperature. In this study, we explored a cold-inducible system using the antifreeze protein (AFP) promoter from a polar diatom, Chaetoceros neogracile. A vector containing the CnAFP promoter (pCnAFP) was generated to regulate nuclear gene expression, and reporter genes (Gaussia luciferase (GLuc) and mVenus fluorescent protein (mVenus)) were successfully expressed in the model microalga, Chlamydomonas reinhardtii. In particular, under the control of pCnAFP, the expression of these genes was increased at low temperature, unlike pAR1, a promoter that is widely used for gene expression in C. reinhardtii. Promoter truncation assays showed that cold inducibility was still present even when pCnAFP was shortened to 600 bp, indicating the presence of a low-temperature response element between -600 and -477 bp. Our results show the availability of new heterologous gene expression systems with cold-inducible promoters and the possibility to find novel low-temperature response factors in microalgae. Through further improvement, this cold-inducible promoter could be used to develop more efficient expression tools.

• Biotechnology and Bioprocess Engineering:BBE
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• 제5권4호
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• pp.247-252
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• 2000

The strength and regulatory characteristics of the heat-inducible HSA1, HSA2 and TPS1 promoters were compared with those of the well-established, carbon source-regulated FMD promoter in a Hansenula polymorpha-based host system in vivo. In addition, the Saccharomyces cerevisiae-derived ADH1 promoter was analysed. While ADH1 promoter showed to be of poor activity in the foreign host, the strength of the heat shock TPS1 promoter was found to exceed that of the FMD promoter, which at present is considered to be the strongest promoter for driving heterologous gene expression in H. polymorpha.

• Applied Biological Chemistry
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• 제39권2호
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• pp.104-111
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• 1996

감자의 genomic DNA library로 부터 분리한 proteinase inhibitor II (pin2) 유전자들의 제한효소 지도를 작성 하였던바 이미 분리된 상처 유발 (wound-inducible)pin2K 유전자의 것과 상이성이 있는 pin2T를 분리하여 염기서열을 결정하였다. 두 유전자의 염기서열은 전체적으로 약 86%의 동일성을 보였으며 특히 promoter 부위의 염기서열은 pin2K 유전자의 전사개시 부위의 상대적인 위치인 -714까지 네부분의 결손(20 내지 60bp)을 제외하던 약 91%수준의동일성을 보였다. 분리한 유전자들의 promoter 부위를 표지 유전자인 CAT와 GUS 유전자에 연결 시킨후 담배에서의 발현을 추적하였던바, pin2K 유전자의 promoter에 의한 표지유전자의 발현은 상처에 의해 발현 되었으나 pin2T 유전자의 promoter에 의한 표지유전자의 발현은 상처 유무와 관계없이 낮은 수준으로 나타났다. 또한 pin2T 유전자의 Promoter 내의 결손은 핵 단백질의 promoter에의 결합에 영향을 주지 않았으며 상처 유발pin2K 유전자의 promoter 염기서열과 비교하였을때 pin2T 유전자의 promoter 부위내에 5'-AGTAAA-3'라는 특별한 염기부위가 자연적으로 제거된것을 알수 있었다. 또한 5'-AGTAAh-3'의 염기부위가 다른 상처 유발 유전자들에서는 흔히 발견되고, 다른 식물 유전자들의 Promoter에서는 쉽게 발견이 되지 않았다. 따라서 상처 유발 pin2K 유전자의 Promoter내에 상처 유발과 관련있는 특별한 염기부위가 자연적으로 결실되어 pin2T 유전자의 발현이 상처 유발성을 잃은것으로 짐작된다.

• Journal of Plant Biotechnology
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• 제4권4호
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• pp.143-150
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• 2002

A strong oxidative stress-inducible peroxidase promoter (referred to as SWPA2 promoter) was cloned from tell cultures of sweetpotato (Ipomoea batatas) and characterized in transgenic tobacco cultured cells in terms of biotechnological applications. Employing a transient expression assay in tobacco protoplasts, with five different 5'-deletion mutants of the SWPA2 promoter fused to the $\beta$-glucuronidase (GUS) reporter gene, the 1314 bp deletion mutant showed approximately 30 times higher GUS expression than the CaMV 35S promoter. The expression of GUS activity in suspension cultures of transgenic cells derived from transgenic tobacco leaves containing the -1314 bp SWPA2 promoter-GUS fusion was strongly expressed following 15 days of subculture compared to other deletion mutants, suggesting that the 1314 bp SWPA2 promoter will be biotechnologically useful for the development of transgenic cell lines engineered to produce key pharmaceutical proteins. In this respect, we developed transgenic cell lines such as tobacco (Nicotiana tabacum L. BY-2), ginseng (Panax ginseng) and Siberian ginseng (Acanthopanax senticosus) using a SWPA2 promoter to produce a human lactoferrin (hLf) and characterized the hLf production in cultured cells. The hLf production monitored by ELISA analysis in transgenic BY-2 cells was directly increased proportional to cell growth and reached a maximal level (up to 4.3% of total soluble protein) at the stationary phase in suspension cultures. The SWPA2 promoter should result in higher productivity and increased applications of plant cultured cells for the production of high-value recombinant proteins.

• Journal of Microbiology
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• 제35권4호
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• pp.277-283
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• 1997

Promoters inducible by paraquat, a superocide-generating agent, were isolated from Escherichia coli using a promoter-probing plasmid pRS415 with promoterless lacA gene. Twenty one promoters induced by paraquat were selected and further characterized. From sequence analysis, thirteen of the promoters were mapped to their specific loci on the Escherichia coli chromosome. Several promoters were mapped to the upstream of known genes such as usgl, katG, and mglB, whose relationships with superoxide response have not been previously reported. Other promoters were mapped to the upstream region of unknown open reading frames. Downstream of HC 96 promoter are uncharacterized ORFs whose sequences are homologous to ABC-transporter subunits. Downstream of HC84 promoter is an ORF encoding a transcriptional regulator-like protein, which contains a LysR family-specific HTH (helix-turn-helix) DNA bindign motif. We investigated whether these promoters belong to the soxRS regulon. All promoters except HC96 were found to belong to the soxRS regulon. The HC96 promoter was significantly induced by paraquat in the soxRS deletion mutant strain. The basal transcription level of three promoters (HE43, HC71, HD94) significantly increased at the stationary phase, implying that they are regulated by RpoS. However, paraquat inducibility of all promoters disappeared in the stationary phase, suggesting that SoxRS regulatory system is active only in rapidly growing cells.

• KSBB Journal
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• 제19권4호
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• pp.327-330
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• 2004

Inducible system을 이용하여 (R)-hydroxybutyric acid (R3HB)를 생산하는 재조합 대장균을 개발하였다. Ralstonia eutropha에서 유래한 PHB depolymerase 유전자를 inducible promoter에 의하여 발현되게 만들고, PHB 생합성 유전자가 있는 vector에 cloning하였다. PHB 생합성 유전자와 depolymerase 유전자를 가지고 있는 재조합 대장균을 배양하여 먼저 PHB를 축적시킨 후에 depolymerase를 발현시켜 배지 내로 분비된 R3HB를 확인하였다. 그 결과 축적된 PHB의 대부분은 발현된 depolymerase에 의하여 분해되었으며, depolymerase의 발현 이후에도 재조합 대장균은 PHB를 축적하고 분해하여 R3HB의 농도는 배양시간에 따라 증가하였다. 이러한 결과는 inducible depolymerase를 갖는 재조합 대장균을 이용하여 높은 농도의 R3IB를 얻을 수 있다는 것을 보여준다.

• Biotechnology and Bioprocess Engineering:BBE
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• 제6권3호
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• pp.167-172
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• 2001

Staphylokinase (SAK) was produced in B. subtilis using two different promoter systems, i.e. the P43 and sacB promoters. To maximize SAK expression in B. subtilis, fermentation control strategies for each promoter were examined. SAK, under P43, a vegetative promoter transcribed mainly by $\sigma$(sup)B containing RNA polymerase, was overexpressed at low dissolved oxygen (D.O.) levels, suggesting that the sigB operon is somewhat affected by the energy charge of the cells. The expression of SAK at the 10% D.O. level was three times higher than that at the 50% D.O. level. In the case of sacB, a sucrose-inducible promoter, sucrose feeding was used to control the induction period and induction strength. Since sucrose is hydrolyzed by two sucrose hydrolyzing enzymes in the cell and culture broth, the control strategy was based on replenishing the loss of sucrose in the culture. With continuous feeding of sucrose, WB700 (pSAKBQ), which contains the SAK gene under sacB promoter, yielded ca. 35% more SAK than the batch culture. These results present efficient promoter-dependent control strategies in B. subtilis host system for foreign protein expression.

• Reproductive and Developmental Biology
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• 제33권1호
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• pp.63-69
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• 2009

In this study we tried to construct a more efficient tetracycline-inducible gene expression system by replacing previous key elements with more advance ones. At the beginning, we substituted PGK (phophoglycerate kinase) promoter for CMV (cytomegalovirus) promoter to control "$rtTA2^sM2$" which has been known for high induction efficiency in response to tetracycline. With this modification, expression of the EGFP marker gene under the induction condition was significantly increased. Next, we replaced "TRE" fragment with a modified version named "TRE-tighf" which has been reported to have higher affinity and specificity to the transactivator by minor base change of the "TRE" DNA fragment sequence. Use of "TRE-tighf" instead of "TRE" resulted in more than 10 fold increment in terms of induction efficiency and significant decrement of background expression in non-inducible condition. By combining PGK promoter and "TRE-tight" fragment, we could upgrade previous tetracycline-inducible system to show more stringent turn on/off gene switch ability and stronger expression of the gene of our interest. Use of this newly developed system must be very helpful to the studies of gene expression, especially to the transgenic animal study in which non-controllable constitutive expression of the transgene has been one of the urgent problems to be solved.

• Journal of Microbiology and Biotechnology
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• 제33권7호
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• pp.955-963
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• 2023

Chlorella is a eukaryotic organism that can be used as an industrial host to produce recombinant proteins. In this study, a salt-inducible promoter (SIP) was isolated from the freshwater species Chlorella vulgaris PKVL7422 from the screening of genes that were upregulated after salt treatment. Several cis-acting elements, including stress response elements, were identified in the isolated SIP. Moreover, the Gaussia luciferase gene was cloned after the SIP and transformed into C. vulgaris to test the inducibility of this promoter. Reexamination of transcriptome of C. vulgaris revealed that genes involved in the synthesis of methyl jasmonic acid (MeJA), gibberellin (GA), and abscisic acid (ABA) were upregulated when C. vulgaris was treated with salt. Furthermore, the expression level of recombinant luciferase increased when the transformed C. vulgaris was treated with salt and MeJA, GA, and ABA. This study represents the first report of the C. vulgaris SIP and highlights how transformed microalgae could be used for robust expression of recombinant proteins.

• 생명과학회지
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• 제15권2호
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• pp.176-181
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• 2005

Calmodulin 유전자의 발현 조절을 연구하기 위해, 벼 calmodulin promoter (RCaM-2)를 분리하여 GUS (report 유전자)에 융합하였다. GUS 활성은 정단조직, 근단 및 관다발 영역과 같은 성장조직에서 높게 발현되었다. 줄기와 페티올의 transverse 절단부위 GUS 활성은 관다발계의 안쪽에 제한되었으며 관다발계의 외부에 위치한 피층과 표피에서는 강하게 발현된 식물에서도 GUS 활성이 나타나지 않았다. GUS 활성은 어린 조직에서 특이적으로 발현되었으며 상처에 의해서 신속하게 증가하였다. RCaM-2 promoter는 세포분열이 왕성한 어린조직이나 생장점에서 강하게 발현되며 mechanical 신호에 의해서 현저히 유도되었다. 이러한 결과는 RCaM-2 유전자의 5'-flanking 영역이 상처에 의해서 유도되는 발현을 조절하는 것으로 추정된다.