• Title/Summary/Keyword: Kozak sequence

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Improved Homologous Expression of the Acidic Lipase from Aspergillus niger

  • Zhu, Si-Yuan;Xu, Yan;Yu, Xiao-Wei
    • Journal of Microbiology and Biotechnology
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    • v.30 no.2
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    • pp.196-205
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    • 2020
  • In this study, the acidic lipase from Aspergillus niger (ANL) was homologously expressed in A. niger. The expression of ANL was significantly improved by the expression of the native ANL with the introns, the addition of the Kozak sequence and the optimization of the signal sequences. When the cDNA sequence of ANL fused with the glaA signal was expressed under the gpdA promoter in A. niger, no lipase activity could be detected. We then tried to improve the expression by using the full-length ANL gene containing three introns, and the lipase activity in the supernatant reached 75.80 U/ml, probably as a result of a more stable mRNA structure. The expression was further improved to 100.60 U/ml by introducing a Kozak sequence around the start codon due to a higher translation efficiency. Finally, the effects of three signal sequences including the cbhI signal, the ANL signal and the glaA signal on the lipase expression were evaluated. The transformant with the cbhI signal showed the highest lipase activity (314.67 U/ml), which was 1.90-fold and 3.13-fold higher than those with the ANL signal and the glaA signal, respectively. The acidic lipase was characterized and its highest activity was detected at pH 3.0 and a temperature of 45℃. These results provided promising strategies for the production of the acidic lipase from A. niger.

Expression of Recombinant Korean Mistletoe(KM) Lectin and B genes in Saccharomyces cerevisiae (Saccharomyces cerevisae에서 한국산 겨우살이 유래 lectin A 및 B 유전자의 발현)

  • 최윤혁;김종배;양웅석;황철원
    • Journal of Life Science
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    • v.14 no.5
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    • pp.840-846
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    • 2004
  • A study for expression of Korean Mistletoe (KM) lectin gene (A,B) in Saccharomyces cerevisiae was done using transforming system of yeast. In order to overexpress the genes efficiently in yeast, two lectin genes (A,B) were re-cloned and modified including Kozak translation initiation sequence using PCR amplification. The constructed plasmids containing modified lectin A and B genes were transformed to S. cerevisea INVSc (MAT G, his3 $\Delta$1, leu2, trpl-289, ura3-52). The transformed cells were identified by DNA sequencing with ABI3700 system and induced with 2% of galactose for recombinant KM lectin (rKM lectin) protein. The rKM lectin A and B proteins were determinated about 29kDa size of protein by SOS-P AGE and western blotting analysis. The expressed recombinant lectin was determinated 1.24∼1.75 $\mu\textrm{g}$ per 1 mg of cytosolic soluble protein by sandwich ELISA method. Moreover the lectin genes were expressed as maximum level at 36 h after galactose induction and lectin A gene was were repressed after 48 h.

Quadriplegia Following Epileptic Seizure : Things to Keep in Mind

  • Kozak, Hasan Huseyin;Yesilbudak, Zulal;Sisman, Lokman;Uca, Ali Ulvi
    • Journal of Korean Neurosurgical Society
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    • v.59 no.3
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    • pp.319-321
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    • 2016
  • People with epilepsy are believed to be at a higher risk of incurring accidental injury than people who do not have seizures. The incidence of injury, either due to seizure or accident as a consequent of seizure is also high and varies from 0.03% to 3%. The most common injuries are head contusions, lacerations, burns and fractures. In this article, we present a case of quadriplegia after a generalized epileptic seizure.

An Association of C/T Polymorphism in the TFF1 Gene and the Susceptibility to Gastric Cancer (TFF1 유전자의 C/T 다형성과 위암 민감성과의 연관성)

  • Maeng, Eun Jae;Song, Jae Hwi;Sung, Soo Yoon;Cao, Zhang;Park, Won Sang
    • Journal of Gastric Cancer
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    • v.8 no.3
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    • pp.113-119
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    • 2008
  • Purpose: This study investigated whether a single nucleotide polymorphism (SNP) located at position -2 in the Kozak sequence of the TFF1 gene is associated with H. pylori infection and the development of gastric cancer in Koreans. Materials and Methods: We enrolled 167 patients with gastric cancer from January 2000 to December 2003 and also 299 healthy controls during the same period. The genotype of the TFF1 SNP was analyzed by polymerase chain reaction-restriction fragment length polymorphism and single strand conformation polymorphism. We also examined the H. pylori infection by Giemsa staining. Results: No significant difference in the allele or the TFF1 SNP genotype frequency was observed between the patients with gastric cancer and the control subjects (P=0.595 and P=0.715, respectively). When stratified by the histological subtype of gastric cancer and the age of the patients, the risk was not statistically significant between the two study groups (P=0.088 and P=0.551, respectively). H. pylori infection was detected in 39 cases and it was not associated with the TFF1 genotype. Conclusion: These findings suggest that this TFF1 gene polymorphism is not associated with H. pylori infection and gastric cancer in Koreans and so it doesn't contribute to the susceptibility to gastric cancer in Koreans.

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Isolation and Characterization of the Colletotrichum acutatum ABC Transporter CaABC1

  • Kim, Suyoung;Park, Sook-Young;Kim, Hyejeong;Kim, Dongyoung;Lee, Seon-Woo;Kim, Heung Tae;Lee, Jong-Hwan;Choi, Woobong
    • The Plant Pathology Journal
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    • v.30 no.4
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    • pp.375-383
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    • 2014
  • Fungi tolerate exposure to various abiotic stresses, including cytotoxic compounds and fungicides, via their ATP-driven efflux pumps belonging to ATP-binding cassette (ABC) transporters. To clarify the molecular basis of interaction between the fungus and various abiotic stresses including fungicides, we constructed a cDNA library from germinated conidia of Colletotrichum acutatum, a major anthracnose pathogen of pepper (Capsicum annum L.). Over 1,000 cDNA clones were sequenced, of which single clone exhibited significant nucleotide sequence homology to ABC transporter genes. We isolated three fosmid clones containing the C. acutatum ABC1 (CaABC1) gene in full-length from genomic DNA library screening. The CaABC1 gene consists of 4,059 bp transcript, predicting a 1,353-aa protein. The gene contains the typical ABC signature and Walker A and B motifs. The 5'-flanking region contains a CAAT motif, a TATA box, and a Kozak region. Phylogenetic and structural analysis suggested that the CaABC1 is a typical ABC transporter gene highly conserved in various fungal species, as well as in Chromista, Metazoans, and Viridiplantae. We also found that CaABC1 was up-regulated during conidiation and a minimal medium condition. Moreover, CaABC1 was induced in iprobenfos, kresoxim-methyl, thiophanate-methyl, and hygromycin B. These results demonstrate that CaABC1 is necessary for conidiation, abiotic stress, and various fungicide resistances. These results will provide the basis for further study on the function of ABC transporter genes in C. acutatum.

Construction of Mammalian Cell Expression Vector for pAcGFP-bFLIP(L) Fusion Protein and Its Expression in Follicular Granulosa Cells

  • Yang, Run Jun;Li, Wu Feng;Li, Jun Ya;Zhang, Lu Pei;Gao, Xue;Chen, Jin Bao;Xu, Shang Zhong
    • Asian-Australasian Journal of Animal Sciences
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    • v.23 no.3
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    • pp.401-409
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    • 2010
  • FLICE inhibitory protein (FLIP) is one of the important anti-apoptotic proteins in the Fas/FasL apoptotic path which has death effect domains, mimicking the pro-domain of procaspase-8. To reveal the intracellular signal transduction molecules involved in the process of follicular development in the bovine ovary, we cloned the c-FLIP(L) gene in bovine ovary tissue with the reverse transcription polymerase chain reaction (RT-PCR), deleted the termination codon in its cDNA, and directionally cloned the amplified c-FLIP(L) gene into eukaryotic expression vector pAcGFP-Nl, including AcGFP, and successfully constructed the fusion protein recombinant plasmid. After identifying by restrictive enzyme BglII/EcoRI and sequencing, pAcGFP-bFLIP(L) was then transfected into follicular granulosa cells, mediated by Lipofectamine 2000, the expression of AcGFP observed and the transcription and expression of c-FLIP(L) detected by RT-PCR and Western blot. The results showed that the cattle c-FLIP(L) was successfully cloned; the pAcGFPbFLIP(L) fusion protein recombinant plasmid was successfuly constructed by introducing a BglII/EcoRI cloning site at the two ends of the c-FLIP(L) open reading frame and inserting a Kozak sequence before the start codon. AcGFP expression was detected as early as 24 h after transfection. The percentage of AcGFP positive cells reached about 65% after 24 h. A 1,483 bp transcription was amplified by RT-PCR, and a 83 kD target protein was detected by Western blot. Construction of the pAcGFP-bFLIP(L) recombinant plasmid should be helpful for further understanding the mechanism of regulation of c-FLIP(L) on bovine oocyte formation and development.