• Animal cells and systems
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• v.15 no.1
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• pp.29-36
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• 2011

Insect lysozymes are basic, cationic proteins synthesized in fat body and hemocytes in response to bacterial infections and depolymerize the bacterial cell wall. The c-type lysozyme of the insect Spodoptera litura (SLLyz) is a single polypeptide chain of 121 residues with four disulfide bridges and 17 rare codons and is approximately 15 kDa. The full-length SLLyz cDNA is 1039 bp long with a poly(A) tail, and contains an open reading frame of 426 bp long (including the termination codon), flanked by a 54 bp long 5' UTR and a 559 bp long 3' UTR. As a host for the production of high-level recombinant proteins, E. coli is used most commonly because of its low cost and short generation time. However, the soluble expression of heterologous proteins in E. coli is not trivial, especially for disulfide-bonded proteins. In order to prevent inclusion body formation, GST was selected as a fusion partner to enhance the solubility of recombinant protein, and fused to the amplified products encoding mature SLLyz. The expression vector pGEX-4T-1/rSLLyz was then transformed into E. coli BL21(DE3)pLysS for soluble expression of rSLLyz, and the soluble fusion protein was purified successfully. Inhibition zone assay demonstrated that rSLLyz showed antibacterial activity against B. megaterium. These results demonstrate that the GST fusion expression system in E. coli described in this study is efficient and inexpensive in producing a disulfide-bonded rSLLyz in soluble, active form, and suggest that the insect lysozyme is an interesting system for future structural and functional studies.

• Genomics & Informatics
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• v.2 no.1
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• pp.45-52
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• 2004

The self-splicing group I intron from Tetrahymena thermophila has been demonstrated to perform splicing reaction with its substrate RNA in the trans configuration. In this study, we explored the potential use of the trans-splicing group I ribozymes to replace a specific RNA with a new RNA that exerts any new function we want to introduce. We have chosen thymidine phosphorylase (TP) RNA as a target RNA that is known as a valid cancer prognostic factor. Cancer-specific expression of TP RNA was first evaluated with RT-PCR analysis of RNA from patients with gastric cancer. We determined next which regions of the TP RNA are accessible to ribozymes by employing an RNA mapping strategy, and found that the leader sequences upstream of the AUG start codon appeared to be particularly accessible. A specific ribozyme recognizing the most accessible sequence in the TP RNA with firefly luciferase transcript as a 3' exon was then developed. The specific trans-splicing ribozyme transferred an intended 3' exon tag sequence onto the targeted TP transcripts, resulting in a more than two fold induction of the reporter activity in the presence of TP RNA in mammalian cells, compared to the absence of the target RNA. These results suggest that the Tetrahymena ribozyme can be a potent anti-cancer agent to modify TP RNAs in tumors with a new RNA harboring anti-cancer activity.

• KSBB Journal
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• v.10 no.3
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• pp.343-348
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• 1995

Human lipocorin-I(LCI) is a calcium ion-dependent and phospholipid-binding protein which exhibits an anti-inflammatory activity by inhibiting phospholipase A2 activity. In this study, the LCI gene containing its own terminator region was joined to GAL10 promoter-ppL (prepro-leader sequence of mating factor a). An ATG start codon of LCI gene was placed at downstream with KR endoprotease recognition site(Lys-Arg) of ppL. Recombinant S. cerevisiae harboring the LCI expression/secretion vector, pYGLPT5, was aerobicall grown on a liquid YPDG medium al $30^{\circ}C$ for 72hys. The whole cell and culture supernatant were separated after centrifugation, and the expressed LCI was analyzed by SDS-PAGE and western blotting methods. A majority fraction of the expressed LCI was found to be accumulated in the intracellular fraction, resulting in very low secretion efficiency of about 7.4%. About $500mg/\ell$ of LCI was extracellularly produced by the fed-batch culture employing the controlledfeeding of glucose and galactose. The secreted LCI was purified by ultrafiltration and hydroxylapatite column chromatography, and a purity of more than 99% was obtained.

• Journal of Microbiology and Biotechnology
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• v.9 no.5
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• pp.582-588
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• 1999

A Brevibacterium lactofermentum gene coding for a glucose-specific permease of the phosphoenolpyruvate-dependent phosphotransferase system (PTS) was cloned, by complementing an Escherichia coli mutation affecting a ptsG gene with the B. lactofermentum genomic library, and completely sequenced. The gene was identified as a ptsG, which enables an E. coli transformant to transport non-metabolizable glucose analogue 2-deoxyglucose (2DG). The ptsG gene of B. lactofermentum consists of an open reading frame of 2,025 nucleotides encoding a polypeptide of 674 amino acid residues and a TAA stop codon. The 3' flanking region contains two stem-loop structures which may be involved in transcriptional termination. The deduced amino acid sequence of the B. lactofermentum enzyme $II^{GIe}$ specific to glucose ($EII^{GIe}$) has a high homology with the Corynebacterium glutamicum enzyme $II^{Man}$ specific to glucose and mannose ($EII^{Man}$), and the Brevibacterium ammoniagenes enzyme $II^{GIc}$ specific to glucose ($EII^{GIc}$). The 171-amino-acid C-terminal sequence of the $EII^{Glc}$ is also similar to the Escherichia coli enzyme $IIA^{GIc}$ specific to glucose ($IIA^{GIc}$). It is interesting that the arrangement of the structural domains, IIBCA, of the B. lactofermentum $EII^{GIc}$ protein is identical to that of EIIs specific to sucrose or $\beta$-glucoside. Several in vivo complementation studies indicated that the B. lactofermentum $EII^{Glc}$ protein could replace both $EII^{ Glc}$ and $EIIA^{Glc}$ in an E. coli ptsG mutant or crr mutant, respectively.

• Korean Journal of Microbiology
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• v.40 no.1
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• pp.7-11
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• 2004

eIF5B is a translation initiation factor that delivers Met-$tRNA^{Met}$ to AUG start codon and subsequently joins the small and large ribosomes. In order to study the function of eIF5B encoded by FUN12, we constructed FUN12 which lacked 5' end of its sequence. We found that this construct lacking almost all of its promoter in pRS plasmid partially complemented slow growth phenotype of fun12 deletion strain. Interestingly, this construct expressed N-terminally truncated eIF5B and its expression level was about 5% of that of wild type eIF5B. Low amount of the eIF5B expressed additionally in fun12 deletion strain played a direct role as a limiting factor for its growth. This limiting factor eIF5B in those strains also modulates activities of overall translation in vitro.

• Journal of Microbiology
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• v.41 no.4
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• pp.340-344
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• 2003

The group I intron from Tetrahymena thermophila has been demonstrated to employ splicing reactions with its substrate RNA in the trans configuration. Moreover, we have recently shown that the transsplicing group I ribozyme can replace HCV-specific transcripts with a new RNA that exerts anti-viral activity. In this study, we explored the potential use of RNA replacement for cancer treatment by developing trans-splicing group I ribozymes, which could replace tumor-associated RNAs with the RNA sequence attached to the 3' end of the ribozymes. Thymidine phosphorylase (TP) RNA was chosen as a target RNA because it is known as a valid cancer prognostic factor. By performing an RNA mapping strategy that is based on a trans-splicing ribozyme library, we first determined which regions of the TP RNA are accessible to ribozymes, and found that the leader sequences upstream of the AUG start codon appeared to be particularly accessible. Next, we assessed the ribozyme activities by comparing trans-splicing activities of several ribozymes that targeted different regions of the TP RNA. This assessment was performed to verify if the target site predicted to be accessible is truly the most accessible. The ribozyme that could target the most accessible site, identified by mapping studies, was the most active with high fidelity in vitro. Moreover, the specific trans-splicing ribozyme reacted with and altered the TP transcripts by transferring an intended 3' exon tag sequence onto the targeted TP RNA in mammalian cells with high fidelity. These results suggest that the Tetrahymena ribozyme can be utilized to replace TP RNAs in tumors with a new RNA harboring anti-cancer activity, which would revert the malignant phenotype.

• Plant Biotechnology Reports
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• v.2 no.1
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• pp.75-85
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• 2008

Prune dwarf virus (PDV) is an Ilarvirus systemically infecting almond trees and other Prunus species and spreading through pollen, among other means. We have studied strategies based on coat protein (cp) gene to block PDV replication in host plant cells. A Portuguese isolate of PDV was obtained from infected almond leaves and used to produce the cDNA of the cp gene. Various constructs were prepared based on this sequence, aiming for the transgenic expression of the original or modified PDV coat protein (cpPDVSense and cpPDVMutated) or for the expression of cpPDV RNA (cpPDVAntisense and cpPDVwithout start codon). All constructs were tested in a PDV host model, Nicotiana benthamiana, and extensive molecular characterization and controlled infections were performed on transformants and their progenies. Transgenic plants expressing the coat protein RNA were able to block the proliferation of a PDV isolate sharing only 91% homology with the isolate used for cpPDV cloning, as evaluated by DAS-ELISA on newly developed leaves. With cp expression, the blockage of PDV proliferation in newly developed leaves was only achieved with the construct cpPDV Mutated, where the coat protein has a substitution in the 14th aa residue, with arginine replaced by alanine. This result points to a possible role of the mutated amino acid in the virus ability to replicate and proliferate. This work reveals the possibility of achieving protection against PDV through either coat protein RNA or mutated cp sequence.

• Molecules and Cells
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• v.26 no.4
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• pp.404-408
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• 2008

The genome of replication-competent BERV ${\gamma}4$ provirus, which is the most abundant ERV family in the bovine genome, was characterized in detail. The BERV ${\gamma}4$ genome showed that BERV ${\gamma}4$ harbors 8576 nucleotides and has the typical 5'-long terminal repeat (LTR)-gag-pro-pol-env-LTR-3' retroviral organization with a long leader region positioned before the gag open reading frame. Multiple sequences analysis showed that the nucleotide difference between 5' and 3' LTRs was 4.2% (mean value 0.042) in average, suggesting that the provirus formed at most 13.3 million years ago. Gag separated by a stop codon from pro-pol in the same reading frame, while env resides in another reading frame lacking of a functional surface domain. According to the current bovine genome sequence assembly, the full-length BERV ${\gamma}4$ provirus sequences were only found in the chromosomes 1, 2, 6, 10, 15, 23, 26, 28, X, and unassigned, although the partial sequences almost evenly distributed in the entire bovine genome. This is the first detailed study describing the genome structure of BERV ${\gamma}4$, the most abundant ERV family present in bovine genome. Combined with our recent reports on characterization of ERVs in bovine, this study will contribute to illuminate ERVs in the cattle of which no information was previously available.

• Molecules and Cells
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• v.23 no.3
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• pp.349-356
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• 2007

Simple Sequence Repeats (SSRs) represent short tandem duplications found within all eukaryotic organisms. To examine the distribution of SSRs in the genome of Brassica rapa ssp. pekinensis, SSRs from different genomic regions representing 17.7 Mb of genomic sequence were surveyed. SSRs appear more abundant in non-coding regions (86.6%) than in coding regions (13.4%). Comparison of SSR densities in different genomic regions demonstrated that SSR density was greatest within the 5'-flanking regions of the predicted genes. The proportion of different repeat motifs varied between genomic regions, with trinucleotide SSRs more prevalent in predicted coding regions, reflecting the codon structure in these regions. SSRs were also preferentially associated with gene-rich regions, with peri-centromeric heterochromatin SSRs mostly associated with retrotransposons. These results indicate that the distribution of SSRs in the genome is non-random. Comparison of SSR abundance between B. rapa and the closely related species Arabidopsis thaliana suggests a greater abundance of SSRs in B. rapa, which may be due to the proposed genome triplication. Our results provide a comprehensive view of SSR genomic distribution and evolution in Brassica for comparison with the sequenced genomes of A. thaliana and Oryza sativa.

• Journal of The Korean Society of Inherited Metabolic disease
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• v.3 no.1
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• pp.32-37
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• 2003

Ornithine transcarbamylase(OTC) deficiency is the most common of all the urea cycle disorders. In this X-linked disorder, the hemizygote males are more severely affected than heterozygote females. The Heterozygote female may have mild episodic hyperammonemia symptoms in late infancy or childhood(late onset) or no clinical manifestations. Here we report a 6 year-old girl with late onset OTC deficiency who showed recurrent episodic lethargy, mental confusion and ataxia. On mutation analysis using DNA sequencing after PCR amplification of the 10 exons of OTC gene, G to T transversion in codon 221, causing substitution of asparagine for lysine was detected in exon 6.