• Title/Summary/Keyword: gene library

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An ${\beta}$-1,4-Xylanase with Exo-Enzyme Activity Produced by Paenibacillus xylanilyticus KJ-03 and Its Cloning and Characterization

  • Park, Dong-Ju;Lee, Yong-Suk;Chang, Jie;Fang, Shu-Jun;Choi, Yong-Lark
    • Journal of Microbiology and Biotechnology
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    • v.23 no.3
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    • pp.397-404
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    • 2013
  • Paenibacillus xylanilyticus KJ-03 was isolated from soil samples obtained from a field with Amorphophallus konjac plants. A gene encoding xylanase was isolated from KJ-03 and cloned using a fosmid library. The xynA gene encodes xylanase; it consists of 1,035 bp and encodes 345 amino acids. The amino acid sequence deduced from the P. xylanilyticus KJ-03 xylanase showed 81% and 69% identities with those deduced from the P. polymyxa E681 and Paenibacillus sp. HPL-001 xylanases, respectively. The xynA gene comprises a single domain, consisting of a catalytic domain of the glycosyl hydrolase (GH) 10 family. The xynA gene was expressed in Escherichia coli BL21 (trxB), and the recombinant xylanase was purified by Niaffinity chromatography. The purified xylanase showed optimum activity with birchwood xylan as a substrate at $40^{\circ}C$ and pH 7.4. Treatment with $Mg^{2+}$ and $Li^+$ showed a slight decrease in XynA activity; however, treatment with 5 mM $Cu^{2+}$ completely inhibited its activity. The results of the thin layer chromatography analysis indicated that the major hydrolysis product was xylobiose and small amounts of xylose and xylotriose. XynA showed increased activity with oat spelt xylan and birchwood xylan, but showed only slight activity with locust bean gum.

A Study on the Development of an Early Embryonic Gene of the Silkworm, Bombyx mori (누에 배형성기 초기 발현 유전자 개발 연구)

  • Choi, Kwang-Ho;Goo, Tae-Won;Kim, Seong-Ryul;Park, Seung-Won;Kim, Sung-Wan;Kang, Seok-Woo
    • Journal of Sericultural and Entomological Science
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    • v.50 no.2
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    • pp.122-125
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    • 2012
  • This study was aimed for a development of a useful gene promoter which has a transcript expressional specificity in the early embryonic period of the silkworm, Bombyx mori. To select a useful gene expressed in the early embryonic stage, we constructed and analyzed a PCR-base subtraction cDNA library. In subtractive hybridization analysis, we confirmed four clones as differently expressed genes(BmNanos-like, BmNanos-P, BmNanos-O, BmVasa mRNAs). Northern hybridization and real time PCR results reveled that the BmNanos-like gene promoter is suitable for the silkworm transgenic vector system. Further defined studies on molecular functions and biological roles of their promoters will give us well-fined information and its application.

Knockdown of vps54 aggravates tamoxifen-induced cytotoxicity in fission yeast

  • Lee, Sol;Nam, Miyoung;Lee, Ah-Reum;Baek, Seung-Tae;Kim, Min Jung;Kim, Ju Seong;Kong, Andrew Hyunsoo;Lee, Minho;Lee, Sook-Jeong;Kim, Seon-Young;Kim, Dong-Uk;Hoe, Kwang-Lae
    • Genomics & Informatics
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    • v.19 no.4
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    • pp.39.1-39.8
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    • 2021
  • Tamoxifen (TAM) is an anticancer drug used to treat estrogen receptor (ER)-positive breast cancer. However, its ER-independent cytotoxic and antifungal activities have prompted debates on its mechanism of action. To achieve a better understanding of the ER-independent antifungal action mechanisms of TAM, we systematically identified TAM-sensitive genes through microarray screening of the heterozygous gene deletion library in fission yeast (Schizosaccharomyces pombe). Secondary confirmation was followed by a spotting assay, finally yielding 13 TAM-sensitive genes under the drug-induced haploinsufficient condition. For these 13 TAM-sensitive genes, we conducted a comparative analysis of their Gene Ontology (GO) 'biological process' terms identified from other genome-wide screenings of the budding yeast deletion library and the MCF7 breast cancer cell line. Several TAM-sensitive genes overlapped between the yeast strains and MCF7 in GO terms including 'cell cycle' (cdc2, rik1, pas1, and leo1), 'signaling' (sck2, oga1, and cki3), and 'vesicle-mediated transport' (SPCC126.08c, vps54, sec72, and tvp15), suggesting their roles in the ER-independent cytotoxic effects of TAM. We recently reported that the cki3 gene with the 'signaling' GO term was related to the ER-independent antifungal action mechanisms of TAM in yeast. In this study, we report that haploinsufficiency of the essential vps54 gene, which encodes the GARP complex subunit, significantly aggravated TAM sensitivity and led to an enlarged vesicle structure in comparison with the SP286 control strain. These results strongly suggest that the vesicle-mediated transport process might be another action mechanism of the ER-independent antifungal or cytotoxic effects of TAM.

Study of a Tobacco MADS-Box Gene Triggering Flower Formation

  • Chung, Yong-Yoon;N, Gynheung-A
    • Proceedings of the Botanical Society of Korea Conference
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    • 1996.07a
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    • pp.10-18
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    • 1996
  • Recently, we have reported a rice MADS-box gene, OsMADS1, as a molecular factor triggering flower formation; this has been well studied in a heterologous system (Chung et al., 1994). In order to study whether the OsMADS1 homolog exists in other plant species, the OsMADS1 cDNA was used as a probe to screen a tobacco cDNA library, and a potential homolog, NtMADS3, was isolated. Sequence analysis revealed that the gene shares 56.1% identity in whole amino acids with OsMADS1. Like OsMADS1, the NtMADS3 gene starts to express at a very early stage of flower development, and the expression continues up to flower maturation. In the tobacco flower, the gene is expressed in whorl 2,3 and 4, corresponding to the petal, stamen, and carpel, respectively. Upon ectopic expression in the homologous system, NtMADS3 caused a trasition from inflorescence shoot meristem into floral meristem, reducing flowering time dramatically. These phenotypes strongly suggest the NtMADS3 gene is the OsMADS1 homolog of tobacco. Hybrids between the OsMADS1 and the NtMADS3 plants were also generated. The hybrids flowered even earlier than these two transgenic plants. The detailed studies are discussed here.

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Construction of a High-Quality Yeast Two-Hybrid Library and Its Application in Identification of Interacting Proteins with Brn1 in Curvularia lunata

  • Gao, Jin-Xin;Jing, Jing;Yu, Chuan-Jin;Chen, Jie
    • The Plant Pathology Journal
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    • v.31 no.2
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    • pp.108-114
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    • 2015
  • Curvularia lunata is an important maize foliar fungal pathogen that distributes widely in maize growing area in China, and several key pathogenic factors have been isolated. An yeast two-hybrid (Y2H) library is a very useful platform to further unravel novel pathogenic factors in C. lunata. To construct a high-quality full length-expression cDNA library from the C. lunata for application to pathogenesis-related protein-protein interaction screening, total RNA was extracted. The SMART (Switching Mechanism At 5' end of the RNA Transcript) technique was used for cDNA synthesis. Double-stranded cDNA was ligated into the pGADT7-Rec vector with Herring Testes Carrier DNA using homologous recombination method. The ligation mixture was transformed into competent yeast AH109 cells to construct the primary cDNA library. Eventually, a high qualitative library was successfully established according to an evaluation on quality. The transformation efficiency was about $6.39{\times}10^5$ transformants/$3{\mu}g$ pGADT7-Rec. The titer of the primary cDNA library was $2.5{\times}10^8cfu/mL$. The numbers for the cDNA library was $2.46{\times}10^5$. Randomly picked clones show that the recombination rate was 88.24%. Gel electrophoresis results indicated that the fragments ranged from 0.4 kb to 3.0 kb. Melanin synthesis protein Brn1 (1,3,8-hydroxynaphthalene reductase) was used as a "bait" to test the sufficiency of the Y2H library. As a result, a cDNA clone encoding VelB protein that was known to be involved in the regulation of diverse cellular processes, including control of secondary metabolism containing melanin and toxin production in many filamentous fungi was identified. Further study on the exact role of the VelB gene is underway.

Molecular Cloning and Characterization of a recA-like Gene Induced by DNA Damage from a Fluorescent Pseudomonas sp.

  • Ok Bong Kim;Na Young Kim;Jae Hoon Jeong;Si Wouk Kim;Hye Gwang Jeong;Seong Myeong Yoon;Jong Kun Park;Jung Sup Lee
    • Animal cells and systems
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    • v.3 no.2
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    • pp.229-236
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    • 1999
  • The recA gene plays a central role in genetic recombination and SOS DNA repair in Escherichia coli (E. coli). We have previously identified a 42 kDa RecA-like protein inducible by a variety of DNA damages from a fluorescent Pseudomonas strain sp. and characterized its inducible kinetics. In the present study, we cloned and characterized the gene encoding the RecA-like protein by immunological screening of Pseudomonas genomic expression library using polyclonal E. coli anti-RecA antibodies as a probe. From 10$^{5}$ plaques screened, five putative clones were finally isolated. Southern blot analysis indicated that four clones had the same DNA inserts and the recA-like gene was located within the 3.2 kb EcoRI fragment of Pseudomonas chromosomal DNA. In addition, the cloned recA-like gene was transcribed into an RNA transcript approximately 1.1 kb in size, as judged by Northern blot analysis. The cellular level of RNA transcript of the cloned recA-like gene was increased to an average of 5.15- fold upon treatment with DNA damaging agents such as ultraviolet (UV)- light, nalidixic acid (NA), methyl methanesulfonate (MMS), and mitomycin-C (MMC). These results suggest that the cloned gene is inducible by DNA damage similarly to the recA gene in E. coli. However, the cloned gene did not restore the DNA damage sensitivity of the E. coli recA-mutant.

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Molecular Cloning of a Defensin Homologue Gene of a Novel Family Member from the Firefly, Pyrocoelia rufa

  • Lee, Kwang-Sik;Park, Hye-Jin;Kim, Seong-Ryul;Lee, Sang-Mong;Sohn, Hung-Dae;Jin, Byung-Rae
    • International Journal of Industrial Entomology and Biomaterials
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    • v.3 no.1
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    • pp.57-62
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    • 2001
  • A cDNA encoding the defensin homologue of a novel family member was isolated from the cDNA library of the firefly,Pyrocoelia rufa. Sequence analysis of the cDNA encoding the defensin homologue of P. rufa resulted that the 165 bp cDHA has an open reading frame of 55 amino acid residues. The deduced amino acid sequences of the defensin homologue gene from P. rufa showed identity to known mammalian defensins. Also 6 cystein residues in the P. rufa defensin homologue gene were conserved in the same position as those of known mammalian defensins. The result suggested that P. rufa defensin homologue is a novel member of the insect defensin family. Southern blot analysis suggests that there may be a single copy number of the P.rufa defensin homologue gene and their fat body-specific expression pattern at the transcriptional level was confirmed by Northern blot analysis.

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Molecular Cloning and Characterization of Mn-Superoxide Dismutase Gene from Candida sp.

  • Hong, Yun-Mi;Nam, Yong-Suk;Choi, Soon-Yong
    • Journal of Microbiology
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    • v.35 no.4
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    • pp.309-314
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    • 1997
  • The manganese-containing superoxide dismutase (MnSOD) is a major component of the cellular defence mechanisms against the toxic effects of the superoxide radical. Within the framework of studies on oxidative stress=responsible enzymes in the Candida sp., the gene encoding the MnSOD was isolated and examined in this study. A specific primer was designed based on conserved regions of MnSOD sequences from other organisms, and was used to isolate the gene by PCR on reverse-transcribed Candida poly($A^{+}$) RNA. The PCR product was used to screen a Candida genomic lambda library and the nucleotide wequence of positive clone was determined. The deduced primary sequence encodes a 25kDa protein which has the conserved residues for enzyme activity and metal binding. The 28 N-terminal amino acids encoded by the Candida cDNA comprise a putatice mitochondrial transit peptide. Potential regulatory elements were identified in the 5' flanking sequences. Northern blot analysis showed that the transcription of the MnSOD gene is induced 5-to 10-fold in response to mercury, cadmium ions and hydrogen peroxide.

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