• BMB Reports
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• v.39 no.6
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• pp.686-695
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• 2006

Interleukin-2 enhancer binding factor 2 (ILF2) was reported to regulate transcription of interleukin-2 (IL-2), a central cytokine in the regulation of T-cell responses. This property of ILF2 was well characterized in human and mammals, but little is known in bony fish. In this paper, an ILF2 homologue was cloned and well characterized from Tetraodon nigrovirid is for the further investigation of the function of ILF2 in bony fish. The full-length Tetraodon ILF2 cDNA was 1380 bp in size and contained an open reading frame (ORF) of 1164 bp that translates into a 387 amino-acid peptide with a molecular weight of 42.9 kDa, a 5' untranslated region (UTR) of 57 bp, and a 3' UTR of 159 bp containing a poly A tail. The deduced peptide of Tetraodon ILF2 shared an overall identity of 58%~93% with other known ILF2 sequences, and contained two N-glycosylation sites, two N-myristoylation sites, one RGD cell attachment sequence, six protein kinase C phosphorylation sites, one amino-terminal RGG-rich single-stranded RNA-binding domain, and a DZF zinc-finger nucleic acid binding domain, most of which were highly conserved through species compared. Constitutive expression of Tetraodon ILF2 was observed in all tissues examined, including gill, gut, head kidney, spleen, liver, brain and heart. The highest expression was detected in heart, followed by liver, head kidney and brain. Stimulation with LPS did not significantly alter the expression of Tetraodon ILF2. Gene organization analysis showed that the Tetraodon ILF2 gene have fifteen exons, one more than other known ILF2 genes in human and mouse. Genes up- and down-stream from the Tetraodon ILF2 were Rpa12, Peroxin-11b, Smad4, Snapap and Txnip homologue, which were different from that in human and mouse.

• Journal of Microbiology and Biotechnology
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• v.18 no.12
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• pp.1945-1952
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• 2008

Sialylation, the attachment of sialic acid residues to a protein, can affect the biological activity and in vivo circulatory half-life of glycoproteins. Human ${\alpha}2$,3-sialyltransferase (${\alpha}2$,3-ST) and ${\beta}1$,4-galactosyltransferase (${\beta}1$,4-GT) are responsible for terminal sialylation and galactosylation, respectively. Enhanced sialylation of human erythropoietin (EPO) by the expression of ${\alpha}2$,3-ST and ${\beta}1$,4-GT was achieved using recombinant Chinese hamster ovary (CHO) cells (EC1). The sialic acid content and sialylation of N-glycans were evaluated by HPLC. When ${\alpha}2$,3-ST was expressed in CHO cells (EC1-ST2), the sialic acid content (moles of sialic acid/mole of EPO) increased from 6.7 to 7.5. In addition, the amount of trisialylated glycans increased from 17.3% to 26.1 %. When ${\alpha}2$,3-ST and ${\beta}1$,4-GT were coexpressed in CHO cells (EC1-GTST15), the degree of sialylation was greater than that in EC1-ST2 cells. In the case of EC1-GTST15 cells, the sialic acid content increased to 8.2 and the proportion of trisialylated glycans was markedly increased from 17.3% to 35.5%. Interestingly, the amount of asialoglycans decreased only in the case of GTST15 cells (21.4% to 14.2%). These results show that coexpression of ${\alpha}2$,3-ST and ${\beta}1$,4-GT is more effective than the expression of ${\alpha}2$,3-ST alone. Coexpression of ${\alpha}2$,3-ST and ${\beta}1$,4-GT did not affect CHO cell growth and metabolism or EPO production. Thus, coexpression of ${\alpha}2$,3-ST and ${\beta}1$,4-GT may be beneficial for producing therapeutic glycoproteins with enhanced sialylation in CHO cells.

• Biomolecules & Therapeutics
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• v.14 no.1
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• pp.30-35
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• 2006

Tissue-type plasminogen activator (t-PA) is a multidomain serine protease containing two kringle domains, TK1-2. Previously, Pichia-derived recombinant human TK1-2 has been reported as an angiogenesis inhibitor although t-PA plays an important role in endothelial and tumor cell invasion. In this work, in order to improve in vivo efficacy of TK1-2 through elimination of immune reactivity, we mutated wild type TK1-2 into non-glycosylated form (NE-TK1-2) and examined whether it retains anti-angiogenic activity. The plasmid expressing NE-TK1-2 was constructed by replacing $Asn^{l17}\;and\;Asn^{184}$ with glutamic acid residues. After expression in Pichia pastoris, the secreted protein was purified from the culture broth using S-sepharose and UNO S1-FPLC column. The mass spectrum of NE-TK1-2 showed closely neighboring two peaks, 19631.87 and 19,835.44 Da, and it migrated as one band in SDS-PAGE. The patterns of CD-spectra of these two proteins were almost identical. Functionally, purified NE-TK1-2 was shown to inhibit endothelial cell migration in response to bFGF stimulation at the almost same level as wild type TK1-2. Therefore, the results suggest that non-glycosylated NETK1-2 can be developed as an effective anti-angiogenic and anti-tumor agent devoid of immune reactivity.

• International Journal of Industrial Entomology and Biomaterials
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• v.3 no.2
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• pp.121-126
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• 2001

A cDNA encoding a cathepsin D homologue was cloned from a cDNA library of the mulberry longicorn beetle, Apriona germari. Sequence analysis of the cDNA encoding the cathepsin D homologue of A. germari revealed that the 1,158 bp cDNA has an open reading frame of 386 amino acid residues. The deduced protein sequence of the A. germari cathepsin D homologue shows high homology with cathepsin D in insects, Aedes aegypti (68.2% amino acid similarity) and Drosophila melanogaster (67.2% amino acid similarity). Two aspartic residues and six cystein residues in the A. germari cathepsin D homologue are present at identical locations in all of the other catepsins D. Unlike cathepsins D in two insect species, A. gemari cathepsin D homologue appears to have two putative glycosylation sites, rather than one. Phylogenetic analysis revealed the A. germari cathepsin D homologue is more closely related to insect cathepsins D than to the other animal cathepsins D. Northern blot analysis suggests that A. germari cathepsin D homologue gene is expressed in most if not all, body tissues.

• Fisheries and Aquatic Sciences
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• v.25 no.1
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• pp.12-19
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• 2022

In the present study, we investigated the effects of recombinant eel gonadotropins (rec-GTHs) on maturation induction in immature ovarian culture in vitro and sex steroid hormones in vivo in the Japanese eel Anguilla japonica. To study the in vitro effects of rec-GTHs on estradiol-17β (E2) production in immature ovarian tissues, ovarian tissues were incubated with different doses of rec-follicle-stimulating hormone (rec-FSH) or rec-luteinizing hormone (rec-LH). The results revealed that the E2 levels in the rec-FSH (0.1, 0.5, or 1 ㎍/mL)- and rec-LH (0.1 or 0.5 ㎍/mL)-treated groups were significantly higher than those in the female eels from the control group. Furthermore, to investigate the in vivo effects of rec-GTHs on the gonadosomatic index (GSI) and plasma sex steroid hormone levels, the eels were injected intraperitoneally with eel's ringer (control), salmon pituitary extract (SPE; for female eels), human chorionic gonadotropin (hCG; for male eels), rec-FSH, rec-LH, and rec-FSH + rec-LH once a week. The results revealed that except for the SPE and the hCG groups, none of the groups exhibited a significant difference in GSI values. However, in vivo plasma E2 levels increased at the end of 4 weeks after rec-FSH treatment in female eels. Based on these results, it is suggested that rec-GTHs may have a positive effect on sexual maturation in female eels; however, further studies on complementary rec-protein production systems and additional glycosylation of rec-hormones are needed to elucidate hormone bioactivity in vivo and in vitro.

• IMMUNE NETWORK
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• v.24 no.1
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• pp.9.1-9.21
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• 2024

The cytokine IL-7 plays critical and nonredundant roles in T cell immunity so that the abundance and availability of IL-7 act as key regulatory mechanisms in T cell immunity. Importantly, IL-7 is not produced by T cells themselves but primarily by non-lymphoid lineage stromal cells and epithelial cells that are limited in their numbers. Thus, T cells depend on cell extrinsic IL-7, and the amount of in vivo IL-7 is considered a major factor in maximizing and maintaining the number of T cells in peripheral tissues. Moreover, IL-7 provides metabolic cues and promotes the survival of both naïve and memory T cells. Thus, IL-7 is also essential for the functional fitness of T cells. In this regard, there has been an extensive effort trying to increase the protein abundance of IL-7 in vivo, with the aim to augment T cell immunity and harness T cell functions in anti-tumor responses. Such approaches started under experimental animal models, but they recently culminated into clinical studies, with striking effects in re-establishing T cell immunity in immunocompromised patients, as well as boosting anti-tumor effects. Depending on the design, glycosylation, and the structure of recombinantly engineered IL-7 proteins and their mimetics, recombinant IL-7 molecules have shown dramatic differences in their stability, efficacy, cellular effects, and overall immune functions. The current review is aimed to summarize the past and present efforts in the field that led to clinical trials, and to highlight the therapeutical significance of IL-7 biology as a master regulator of T cell immunity.

• Journal of Microbiology and Biotechnology
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• v.13 no.6
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• pp.926-936
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• 2003

Overexpression of human Bcl-2 protein in recombinant Chinese hamster ovary (rCHO) cells producing humanized antibody (SH2-0.32) considerably suppressed sodium butyrate (NaBu)-induced apoptosis during batch culture by using commercially available serum-free medium, which extended the culture longevity. Due to the extended culture longevity provided by the anti-apoptotic effect of Bcl-2 overexpression, the final antibody concentration of 14C6-bcl-2 culture (Bcl-2 high producer, $23\;\mu\textrm{g}\;ml^{-1}$) was 2 times higher than that of the $SH2-0.32-{\Delta}bcl-2$ culture (cells transfected with bcl-2-deficient plasmid, $10.5\;\mu\textrm{g}\;ml^{-1}$) in the presence of NaBu. To determine the effect of NaBu/Bcl-2 overexpression on the molecular integrity of protein products, antibodies purified from 14C6-bcl-2 and $SH2-0.32-{\Delta}bcl-2$ cultures in the presence of NaBu were characterized by using various molecular assay systems. For comparison, antibody purified from the parental rCHO cell culture (SH2-0.32) in the absence of NaBu was also characterized. No significant changes in molecular weight of antibodies could be observed by SDS-PAGE. From GlycoSep-N column analysis, it was found that the core oligosaccharide structure ($GlcNAc_2Man_3GlcNAc_2$) was not affected by NaBu/Bcl-2 overexpression, while the microheterogeneity of N-linked oligosaccharide structure was slightly affected. Compared with the antibody produced in the absence of NaBu, the proportion of neutral oligosaccharides was increased from 10% (14C6-bcl-2) to 16% ($SH2-0.32-{\Delta}bcl-2$) in the presence of NaBu, which was accompanied by the reduced proportion of acidic oligosaccharides, especially of monosialylated and disialylated forms. The changes in microheterogeneous oligoformal structures of antibody in turn affected the mobility of antibody isoforms in isoelectric focusing (IEF), resulting in the occurrence of some more basic antibody isoforms produced in the presence of NaBu. However, the antigen-antibody binding properties were not changed by alteration of glycosylation pattern. The competitive enzyme-linked immunosorbent assay (ELISA) showed that the antibody produced by NaBu/Bcl-2 overexpression maintained its antigen-antibody binding properties with binding affinity of about $2.5{\times}10^9{\;}M^{-1}$. Taken together, no significant effects of NaBu/Bcl-2 overexpression on the molecular integrity of antibodies, produced by using serum-free medium, could be observed by the molecular assay systems.

• Reproductive and Developmental Biology
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• v.30 no.2
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• pp.81-85
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• 2006

This study was conducted to examine the effect of IRES controlled reporter gene on screening and production of recombinant human erythropoietin (EPO) proteins from cultured CHO cells. The cDNA was cloned for EPO from human liver cDNA Using site-directed mutagenesis, we generated recombinant human EPO (rhEPO) with two additional N-glycosylations (Novel erythropoiesis-stimulating protein: NESP). Wild type hEPO and NESP were cloned into expression vectors with GFP reporter gene under regulatory control of CMV promoter and IRES so that the vectors could express both rhEPO and GFP. The expression vectors were transfected to cultured CHO-K1 cells. Under microscopy, expression of GFP was visible. Using supernatant of the culture, ELISA assay, immunocytochemistry and in vitro assay using EPO dependant cell line were performed to estimate biological activity to compare the production characteristics (secretion levels, etc.) between rhEPO and NESP. The activity of NESP protein, obtained by mutagenesis, was described and compared with its rhEPO counterpart produced under same conditions. Although NESP had less secretion level in CHO cell line, the biological activity of NESP was greater than that of rhEPO. These results are consistent with previous researches. We also demonstrated that rhEPO and GFP proteins expressed simultaneously from transfected CHO cell line. Therefore we conclude that use of GFP reporter gene under IRES control could be used to screen and produce rhEPO in cultured CHO cells.

• Journal of Life Science
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• v.13 no.5
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• pp.596-603
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• 2003

Cells respond to an accumulation of unfolded proteins in the endoplasmic reticulum (ER) by increasing transcription of genes encoding molecular chaperones and folding enzymes. The information is transmitted from the ER lumen to the nucleus by intracellular signaling pathway, called the unfolded protein response (UPR). To obtain genes related to UPR from B. mori, the cDNA library was constructed with mRNA isolated from Bm5 cell lines in which N-glycosylation was inhibited by tunicamycin treatment. From the cDNA library, we selected 40 clones that differentially expressed when cells were treated with tunicamycin. Among these clones, we have isolated ATFC gene showing similarity with Hac1p, encoding a bZIP transcription factor of 5. cerevisiae. Basic-leucine zipper (bZIP) domain in amino acid sequences of ATFC shared homology with yeast Hac1p. Also, ATFC is up-regulated by accumulation of unfolded proteins in the ER through the treatment of ER stress drugs. Therefore we suggest that ATFC represents a major component of the putative transcription factor responsible for the UPR leading to the induction of ER-localized stress proteins.

• Journal of Microbiology and Biotechnology
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• v.19 no.9
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• pp.987-996
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• 2009

Aspergillus niger GH1 previously isolated and identified by our group as a wild tannase producer was grown under solid-state (SSC) and submerged culture (SmC) conditions to select the enzyme production system. For tannase purification, extracellular tannase was produced under SSC using polyurethane foam as the inert support. Tannase was purified to apparent homogeneity by ultrafiltration, anion-exchange chromatography, and gel filtration that led to a purified enzyme with a specific activity of 238.14 IU/mg protein with a final yield of 0.3% and a purification fold of 46. Three bands were found on the SDS-PAG with molecular masses of 50, 75, and 100 kDa. PI of 3.5 and 7.1% N-glycosylation were noted. Temperature and pH optima were 600e and 6.0 [methyl 3,4,5-trihydroxybenzoate (MTB) as substrate], respectively. Tannase was found with a $K_M$ value of $0.41{\times}10^{-4}M$ and the value of $V_{max}$ was $11.03{\mu}$moL/min at $60^{\circ}C$ for MTB. Effects of several metal salts, solvents, surfactants, and typical enzyme inhibitors on tannase activity were evaluated to establish the novelty of the enzyme. Finally, the tannase from A. niger GH1 was significantly inhibited by PMSF (phenylmethylsulfonyl fluoride), and therefore, it is possible to consider the presence of a serine or cysteine residue in the catalytic site.