• 한국동물학회:학술대회논문집
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• 한국동물학회 2003년도 한국생물과학협회 학술발표대회
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• pp.211.3-211
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• 2003

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• 한국미생물학회:학술대회논문집
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• 한국미생물학회 2002년도 추계학술대회
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• pp.162-172
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• 2002

Schizosaccharomyces pombe is suited for the study of cytokinesis as it divides by forming a septum in the middle of the cell at the end of mitosis. To enhance our understanding of the cytokinesis, we have carried out a genetic screen for temperature-sensitive S. pombe mutants that show defects in septum formation and cell division. Here we present the isolation and characterization of a new temperature-sensitive mutant, sun1(septum uncontrolled), which undergoes uncontrolled septation during cell division cycle at restrictive temperature $(37^{\circ}C)$. In sun1 mutant, actin ring and septum are positioned at random locations and angles, and nuclear division cycle continues. These observations suggest that the sun] gene product is required for the proper placement of the actin ring as well as precise septation. The sun] mutant is monogenic recessive mutation unlinked to previously known various cdc genes of S. pombe. In a screen for $sunl^+$ gene to complement the sun] mutant, we have cloned a gene, $susl^+$(suppressor of sun1 mutant), that encodes a protein of 689 amino acids. The predicted amino acid sequence of $susl^+$ gene is similar to the human hMadlp and Saccharomyces cerevisiae Mad1p, a component of the spindle checkpoint in eukaryotic cells. The null mutant of $susl^+$ gene grows normally at various temperatures and has the increased sensitivity to anti-microtubule drug, while $susl^+$ mutant shows no sensitivity to microtubule destabilizing drugs. The putative S. pombe Sus1p directly interacts with S. pombe Mad2p in yeast two-hybrid assays. These data suggest that the newly isolated susr gene encodes S. pombe Mad1p and suppresses sun] mutant defective in controlled septation in a cell division cycle.

• 한국식품영양과학회지
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• 제33권6호
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• pp.1017-1021
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• 2004

Thr, Trp을 overproduce하는 효모 균주를 분리하기 위하여 Sacchromyces cerevisiae를 UV와 EMS로 mutagenesis한 후 screen하였다. Thr analogue인 hydroxynorvaline이 UV mutagenesis 후 Thr overproducing 하기 위해 사용되었다. 31 mutant 중 아미노산 분석 결과에 의해 TC 5-1이 선정되었고 다시 Trp overproducing 위해 EMS mutagenesis 하였다. 8개의 mutant가 flurotryptophan을 이용하여 Thr, Trp을 overproduce하는 mutant로 선정되었다. 아미노산결과에 의해 그 중 TC 6-1이 최종 효모 균주로 선정되었다.

• Journal of Photoscience
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• 제3권1호
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• pp.23-28
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• 1996

To investigate the structure and function of photosystem I, cartridge mutagenesis technique was used to inactivate the psaB gene of photosystem I. From the screen, many strains which have potential defects in photosystem I were generated. Biochemical analysis revealed that B2, one of the mutant, had a reduced amount of chlorophyll. Electron transfer activitx from photosystem II to photosystem I as oxygen uptake was the rate of 64 % of wild type. Also B2 showed a decreased photosystem I activity when measured by 77 K fluorescence emission spectrum. Particularly, immunodetection analysis showed that the B2 had reduced amount of PsaA/PsaB, but a normal range of PsaC and PsaD. Here we present a photoheterotrophic mutant for psaB gene as a unique model strain for future study of structural/functional relationship and biogenesis of photosystem I.

• KSBB Journal
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• 제14권2호
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• pp.235-240
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• 1999

Trigonopsis variabilis ATCC10679 (TW)의 변이균주를 선별하기 위하여 쉽고 간편한 균주 선별방법을 개발하였다. 변이 균주(T26)의 D-Amino acid oxidase (D-AAO)는 야생균주(TW)의 D-AAO 효소보다 cephalosporin C에 대한 기질특이성이 약 30% 높았다. 이들 두 균주에서 D-AAO 유전자를 클로닝하여 각 유전자를 비교해본 결과 811번 우치의 T가 C로 변경되었으며 이에 따른 아미노산은 Phe-258이 Ser-258로 바뀌었다.

• Biomolecules & Therapeutics
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• 제31권1호
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• pp.48-58
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• 2023

Interferon regulatory factor 3 (IRF3) integrates both immunological and non-immunological inputs to control cell survival and death. Small GTPases are versatile functional switches that lie on the very upstream in signal transduction pathways, of which duration of activation is very transient. The large number of homologous proteins and the requirement for site-directed mutagenesis have hindered attempts to investigate the link between small GTPases and IRF3. Here, we constructed a constitutively active mutant expression library for small GTPase expression using Gibson assembly cloning. Small-scale screening identified multiple GTPases capable of promoting IRF3 phosphorylation. Intriguingly, 27 of 152 GTPases, including ARF1, RHEB, RHEBL1, and RAN, were found to increase IRF3 phosphorylation. Unbiased screening enabled us to investigate the sequence-activity relationship between the GTPases and IRF3. We found that the regulation of IRF3 by small GTPases was dependent on TBK1. Our work reveals the significant contribution of GTPases in IRF3 signaling and the potential role of IRF3 in GTPase function, providing a novel therapeutic approach against diseases with GTPase overexpression or active mutations, such as cancer.

• Applied Biological Chemistry
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• 제4권
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• pp.11-16
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• 1963

Penicillium균(菌) 30주(株) Aspergillus균(菌) 52주(株)의 5'-Phosphodiesterase activity를 screen하여 강력(强力)한 Penicillium sclerotiorum 6321, Penicillium SP M-11 그리고 Penicillium citrinum UV-mutant 2032-72 선발(選拔)하였다. (2) 밀기울 배지(培地)호 $30^{\circ}C$ 10일(日)의 정치배양(靜置培養)에서 5‘-Phosphodiesterase생산(生産)이 강(强)했다. (2) Penicillium sclerotiorum 7321가 Penicillium SP M-11의 5‘-Phosphodiesterase 최적조건(最適條件)이 pH 4.0, $62.^{\circ}C$이고 Penicillium citrinum UV-mutant 2032-72 의 5'-Phosphodiesterase 최적조건(最適條件)은 PH5.0, $50^{\circ}C$이다.

• 통합자연과학논문집
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• 제4권2호
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• pp.113-120
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• 2011

Brassinosteroids (BRs) are plant steroid hormones that play essential roles in growth and development. Mutations in BR-signaling pathways cause defective in growth and development like dwarfism, male sterility, abnormal vascular development and photomorphogenesis. Transition from vegetative to reproductive growth is a critical phase change in the development of a flowering plant. In a screen of activation-tagged Arabidopsis, we identified a mutant named abz126 that displayed longer hypocotyls when grown in the dark on MS media containing brassinazole (Brz), an inhibitor of BRs biosynthesis. We have cloned the mutant locus using adapter ligation PCR walking and identified that a single T-DNA had been integrated into the ninth exon of the GIGANTEA (GI) gene, involved in controling flowering time. This insertion resulted in loss-of-function of the GI gene and caused the following phenotypes: long petioles, tall plant height, many rosette leaves and late flowering. RT-PCR assays on abz126 mutant showed that the T-DNA insertion in GIGANTEA led to the loss of mRNA expression of the GI gene. In the hormone dose response assay, abz126 mutant showed: 1) an insensitivity to paclobutrazole (PAC), 2) an altered response with 6-benzylaminopurine (BAP) and 3) insensitive to Brassinolide (BL). Based on these results, we propose that the late flowering and tall phenotypes displayed by the abz126 mutant are caused by a loss-of-function of the GI gene associated with brassinosteroid hormone signaling.

• 한국미생물·생명공학회지
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• 제6권3호
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• pp.129-133
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• 1978

Trichoderma viride QM 9414의 생육을 저해하여 colony를 형성 시키고 배지에 첨가된 cellulose가 균이 분비한 cellulase에 의해서 분해되어 생긴 clear zone으로서 육안으로 cellulase 역가를 쉽게 측정할 수 있는 방법과 repressor를 첨가하여 constitutive mutant를 선별할 수 있는 방법에 관한 실험을 하였든 바 그 결과를 요약하면 다음과 같다. 1) Colony를 형성시키고 그 size를 제한 하는데는 deoxycholate를 배지에 0.15％ 첨가 하였을 때 가 가장 좋았다. 2) Saponin을 배지에 0.l％ 첨가하면 뚜렷한 clear zone을 형성하였다. 3) Constitutive mutant를 선별하기 위해서는 기질로 pulp를 사용하였을 경우 glucsoe를 1％ 첨가하거나 glycerol이나 cellobiose를 0.5％ 첨가하면 가능하다고 생각되며 기질로 pure cellulose를 사용하였을 경우는 그대로 배지에 spore를 plating하면 가능하다고 생각된다. 4) Cellulase 역가가 높은 균주는 clear zone의 크기로서 쉽게 분리할 수 있다.

• Molecules and Cells
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• 제44권12호
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• pp.900-910
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• 2021

Sour is one of the fundamental taste modalities that enable taste perception in animals. Chemoreceptors embedded in taste organs are pivotal to discriminate between different chemicals to ensure survival. Animals generally prefer slightly acidic food and avoid highly acidic alternatives. We recently proposed that all acids are aversive at high concentrations, a response that is mediated by low pH as well as specific anions in Drosophila melanogaster. Particularly, some carboxylic acids such as glycolic acid, citric acid, and lactic acid are highly attractive to Drosophila compared with acetic acid. The present study determined that attractive carboxylic acids were mediated by broadly expressed Ir25a and Ir76b, as demonstrated by a candidate mutant library screen. The mutant deficits were completely recovered via wild-type cDNA expression in sweet-sensing gustatory receptor neurons. Furthermore, sweet gustatory receptors such as Gr5a, Gr61a, and Gr64a-f modulate attractive responses. These genetic defects were confirmed using binary food choice assays as well as electrophysiology in the labellum. Taken together, our findings demonstrate that at least two different kinds of receptors are required to discriminate attractive carboxylic acids from other acids.