• BMB Reports
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• 제30권2호
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• pp.95-100
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• 1997

Two kinds of cDNA encoding mouse $Gal{\beta}$1,3(4)GlcNAc ${\alpha}$2,3-sialyltransferase (mST3Gal III) and $Gal{\beta}$1,4(3)GlcNAc ${\alpha}$2,3-sialyltransferase (mST3Gal IV) were isolated from mouse brain cDNA library by means of a PCR-based approach. The cDNA sequences included an open reading frame coding for proteins of 374 and 333 amino acids, respectively, and the primary structure of these enzymes suggested a putative domain structure consisting of four regions, like that in other glycosyltransferases. The deduced amino acid sequences of mST3GaI III and IV showed a 98% and 89% identity with rat ST3GaI III and human ST3Gal IV, respectively. Northern analysis indicated that the expression of mST3Gal III mRNA was abundant in heart, liver and adult brain, while that of mST3GaI IV mRNA was detected in all tissues tested except for testis, but the level was the highest in liver. Soluble forms of mST3GaI III and IV transiently expressed in COS cells exhibited enzyme activity toward acceptor substrates containing the terminal either $Gal{\beta}$1,3GlcNAc or $Gal{\beta}$1,4GlcNAc sequences. The substrate preferences of both enzymes were stronger for tetrasaccharides than for disaccharides.

• Archives of Pharmacal Research
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• 제22권3호
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• pp.243-248
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• 1999

Sialic acids are key determinants for biological processes, such as cell-cell interaction and differentiation. Sialyltransferases contribute to the diversity in carbohydrate structure through their attachment of sialic acid in various terminal positions on glycolipid and glycoprotein (N-linked and O-linked) carbohydrate groups. Gal$\beta$ 1,3(4)GlcNAc $\alpha$2,3-sialyltransferase (ST3Gal III) is involved in the biosynthesis of $sLe^{X}$ and sLe^{a}$ known as selection ligands and tumor-associated carbohydrate structures. The appearance and differential distribution of ST3Gal III mRNA during mice embryogenesis [embryonic (E) days; E9, E11, E13, E15] were investigated by in situ hybridization with digoxigenin-labeled RNA probes coupled with alkaline phosphatase detection. On E9, all tissues were positive for ST3Gal III mRNA expression whereas ST3Gal III mRNA on E11 was not detected throughout all tissues. On E13, ST3GAl III mRNA was expressed in different manner in various tissues. In this stage, ST3Gal III mRNA was positive only in the liver, pancreas and bladder. On E15, specific signal for ST3GAl III was detected in the liver, lung and forebrain. These results indicate that ST3Gal III is differently expressed at developmental stages of mice embryo, and this may be importantly related with regulation of organogenesis in mice.

• Journal of Life Science
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• 제11권1호
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• pp.57-64
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• 2001

The cDNA encoding human NeuAc ${\alpha}$2,3Gal$\beta$ 1,3GalNAc GalNac ${\alpha}$2,6-Sialyltransferase (hST6GalNac IV) was isolated by screening of human fetal liver cDNA library with a DNA probe generated from the cDNA sequence of mouse ST6Gal NAc IV (mkST6GalNAc IV). The cDNA sequence included an open reading frame coding for 302 amino acids, and comparative analysis of this cDNA with mST6GalNAc IV showed that each sequence of the predicted coding region contains 88% and 85% identifies in nucleotide and amino acid levels, respecively. The primary structure of this enzyme suggested a putative domain structure, like that in other glycosyltransferases, consisting of a short N-terminal cytoplamic domain, a transmembrane domain and a large C-terminal active domain. This enzyme expressed in COS-7 cells echibited transferase activity toward NeuAc ${\alpha}$2,3Gal$\beta$ 1,3GalNAc, fetuin and GM1b, although the activity toward the later is very low, no significant activity being detected toward Gal${\beta}$ 1,3Gal NAc or asialofetuin, the other glycoprotein substrates tested. The $^{14}$ C-sialylated residue of fetuin sialylated by this enzyem with CMP-[$^{14}$C]NeuAc was sensitive to treatment with ${\alpha}$2,8-specific sialidase of Vibrio cholerae but resistant to treatment with ${\alpha}$2,3-specific sialidase (NaNase I), and ${\alpha}$2,3- and ${\alpha}$2,8-specific sialidase of Newcastle disease virus. These results clearly indicated that the expressed enzyme is a type of GalNAc ${\alpha}$2,6-sialyltransferase like mST6GalNAc IV, which requires sialic acid residues linked to Gal${\beta}$1,3GalNAc-residues for its activity.

• Journal of Life Science
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• 제10권1호
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• pp.51-56
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• 2000

In many cases of human cancer, the appearance of hypersialylated glycan structures is related to a precise stage of the disease ; this may depend on the elebated sialyltransferase activity during carcinogenesis. The aim of this study was to investigate the inhibitory effects of Oriental medicinal herbs on enzymatic activities of two kinds ofsialyltransferase, Gal $\beta$ 1,3GalNAc$\alpha$2,3-sialyltransferase(ST3Gal I) and Gal $\beta$ 1,4GlcNAc $\alpha$2,6-sialyltransterases(ST6Gal I), which are well known as glycosyltransterases associated with cancer. The aqueous extracts of Scutellaria Baicalensis Georgi, Coptidis Rhizoma, Glycyrrhiza urlensis Fisch, Bupleuri Radix and Platycodi Radix were prepared and tested, respectively. At concentration of 100$\mu$g, Glycyrrhiza uralensis Fisch showed the highest inhibitory effects(about 42% and 57%, respectively) on ST3Gal Iand ST6Gal Iactivities. ST3GAl I was inhibited about 23% by Scutellaria baicalensi G댁햐, but not by the other samples, whereas ST6Gal I was inhibited about 20% and 40%,respectively, by Scutellaria baicalensis Georgi and Bupleuri Radix. All inhibitory effects were obtained in a concentration-dependent manner.

• 한국수정란이식학회지
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• 제32권1호
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• pp.17-24
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• 2017

Ganglioside GD1a is specifically formed by the addition of sialic acid to ganglioside GM1a by ST3 ${\beta}$-galactoside ${\alpha}$-2,3-sialyltransferase 2 (ST3GAL2). Above all, GD1a are known to be related with the functional regulation of several growth factor receptors, including activation and dimerization of epidermal growth factor receptor (EGFR) in tumor cells. The activity of EGF and EGFR is known to be a very important factor for meiotic and cytoplasmic maturation during in vitro maturation (IVM) of mammalian oocytes. However, the role of gangliosides GD1a for EGFR-related signaling pathways in porcine oocyte is not yet clearly understood. Here, we investigated that the effect of ST3GAL2 as synthesizing enzyme GD1a for EGFR activation and phosphorylation during meiotic maturation. To investigate the expression of ST3GAL2 according to the EGF treatment (0, 10 and 50 ng/ml), we observed the patterns of ST3GAL2 genes expression by immunofluorescence staining in denuded oocyte (DO) and cumulus cell-oocyte-complex (COC) during IVM process (22 and 44 h), respectively. Expression levels of ST3GAL2 significantly decreased (p<0.01) in an EGF concentration (10 and 50 ng/ml) dependent manner. And fluorescence expression of ST3GAL2 increased (p<0.01) in the matured COCs for 44 h. Under high EGF concentration (50 ng/ml), ST3GAL2 protein levels was decreased (p<0.01), and their shown opposite expression pattern of phosphorylation-EGFR in COCs of 44 h. Phosphorylation of EGFR significantly increased (p<0.01) in matured COCs treated with GD1a for 44 h. In addition, ST3GAL2 protein levels significantly decreased (p<0.01) in GD1a ($10{\mu}M$) treated COCs without reference to EGF pre-treatment. These results suggest that treatment of exogenous ganglioside GD1a may play an important role such as EGF in EGFR-related activation and phosphorylation in porcine oocyte maturation of in vitro.

• BMB Reports
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• 제44권6호
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• pp.405-409
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• 2011

The present study demonstrated that valproic acid (VPA) transcriptionally regulates human GM3 synthase (hST3Gal V), which catalyzes ganglioside GM3 biosynthesis in ARPE-19 human retinal pigment epithelial cells. For this, we characterized the promoter region of the hST3Gal V gene. Functional analysis of the 5'-flanking region of the hST3Gal V gene revealed that the -177 to -83 region functions as the VPA-inducible promoter and that the CREB/ATF binding site at -143 is crucial for VPA-induced expression of hST3Gal V in ARPE-19 cells. In addition, the transcriptional activity of hST3Gal V induced by VPA in ARPE-19 cells was inhibited by SP600125, a c-Jun N-terminal kinase (JNK) inhibitor. In summary, our results identified the core promoter region in the hST3Gal V promoter and for the first time demonstrated that ATF2 binding to the CREB/ATF binding site at -143 is essential for transcriptional activation of hST3Gal V in VPA-induced ARPE-19 cells.

• 한국생명과학회:학술대회논문집
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• 한국생명과학회 2002년도 제38회 학술심포지움
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• pp.13-19
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• 2002

To elucidate the regulatory mechanism for expression of sialyl-glycoconjugates and their biological functions, ninetheen sialyltransferase cDNAs including eleven by our group or co-works have been cloned and characterized so far. The cloned sialyltransferases are classified into four families according to the carbohydrate linkages they synthesize: ${\alpha}2,3-sialyltransferase$ (ST3Gal I-VI), ${\alpha}$ 2,6-sialyltransferase (ST6Gal I), GalNAc ${\alpha}$ 2,6-sialyltransferase (ST6GalNAc I-VI), and ${\alpha}2,8-sialyltransferase$ (ST8Sia I-VI). Each of the sialyltransferase genes is differentially expressed in a tissue-, cell type-, and stage-specific manner. These enzymes differ in their substrate specificity and various biochemical parameters. However, enzymatic analysis conducted in vitro with recombinant enzyme revealed that one linkage can be synthesized by multiple enzymes. We present here an overview of structure and function of sialyltransferases performed by our group and co-works. Genomic structures and transcriptional regulation of two kinds of human sialyltransferase gene are also presented.

• Reproductive and Developmental Biology
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• 제35권4호
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• pp.511-518
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• 2011

To avoid hyperacute rejection of xenografts, ${\alpha}1,3$-galactosyltransferase knock-out (GalT KO) pigs have been produced. In this study, we examined whether Sia-containing glycoconjugates are important as an immunogenic non-Gal epitope in the pig liver with disruption of ${\alpha}1,3$-galactosyltransferase gene. The target cells were then used as donor cells for somatic cell nuclear transfer (scNT). A total of 1,800 scNT embryos were transferred to 10 recipients. One recipient developed to term and naturally delivered two piglets. Real-time RT-PCR and glycosyltransferase activity showed that ${\alpha}2,3$-sialyltransferase (${\alpha}2,3ST$) and ${\alpha}2,6$-sialyltransferase (${\alpha}2,6ST$) in the heterozygote GalT KO liver have higher expression levels and activities compared to controls, respectively. According to lectin blotting, sialic acidcontaining glycoconjugate epitopes were also increased due to the decreasing of ${\alpha}$-Gal in heterozygote GalT KO liver, whereas GalNAc-containing glycoconjugate epitopes were decreased in heterozygote GalT KO liver compare to the control. Furthermore, the heterozygote GalT KO liver showed a higher Neu5Gc content than control. Taken together, these finding suggested that the deficiency of GalT gene in pigs resulted in increased production of Neu5Gc-bounded epitopes (H-D antigen) due to increase of ${\alpha}2,6$-sialyltransferase. Thus, this finding suggested that the deletion of CMAH gene to the GalT KO background is expected to further prolong xenograft survival.

• Journal of Acupuncture Research
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• 제17권2호
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• pp.95-117
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• 2000

The purpose of this morphological studies was to investigate the relation between the meridian, acupoints and viscera using neuroanatomical tracers. The common locations of the spinal ganglia, sympathetic chain ganglia, spinal cord and brain projecting to the large intestine meridian were observed following injection of transganglionic tracer, WGA-HRP and transsynaptic neurotropic virus, pseudorabies virus(PRV), Bartha strain(Ba) and PRV-Ba-Gal (Galactosidase)) into the the large intestine(cecum, colon and rectum), ST37 and LI4. After survival times of 96 hours following injection into the thirty rats with WGA-HRP, PRV-Ba and PRV-Ba-Gal. They were perfused, and their spinal ganglia, sympathetic chain ganglia, spinal cord and brain were frozen sectioned($30{\mu}m$). These sections were stained by HRP and X-gal histochemical and PRV immunohistochemical staining method, and observed with a light microscope. The results were as follows : 1. WGA-HRP labeled neurons innervating the large intestine were observed bilaterally within the T13-L4 sympathetic chain ganglia, and T9-11 spinal ganglia. WGA-HRP labeled neurons innervating ST37 were observed within the L3-5 sympathetic chain ganglia, and L2-4 spinal ganglia. WGA-HRP labeled neurons innervating LI4 were observed in the middle cervical ganglion and stellate ganglion, and C5-8 spinal ganglia. 2. In spinal cord, PRV-Ba labeled neurons projecting to the large intestine, ST37 and LI4 were found in thoracic, lumbar and sacral spinal segments. Densely labeled areas of each spinal cord segment were founded in lamina N, V, VII(intermediolateral nucleus), Ⅸ, X and dorsal nucleus. 3. In medulla oblongata, PRV-Ba and PRV-Ba-Gal labeled neurons projecting to the large intestine, ST37 and LI4 were commonly found in the A1 noradrenalin cells/C1 adrenalin cells/caudoventrolateral reticular nucleus, dorsal motor nucleus of vagus nerve, nucleus tractus solitarius, raphe obscurus nucleus, raphe pallidus nucleus, raphe magnus nucleus and gigantocellular nucleus. 4. In pons, PRV-Ba and PRV-Ba-Gal labeled neurons were commonly found in locus coeruleus, Kolliker-Fuse nucieus and A5 cell group. 5. In midbrain, PRV-Ba and PRV-Ba-Gal labeled neurons were commonly found in central gray matter. 6. In diencephalon, PRV-Ba and PRV-Ba-Gal labeled neurons were commonly found in paraventricular hypothalamic nucleus. These results suggest that PRV-Ba and PRV-Ba-Gal labeled common areas projecting to the large intestine may be correlated to that of the large intestine meridian, ST37 and LI4. Especially, These morphological results provide that interrelationship of meridian-acupoints -viscera may be related to the central autonomic pathways.

• 한국생명과학회:학술대회논문집
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• 한국생명과학회 2008년도 제49회 학술심포지움 및 국제학술대회
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• pp.53.1-53.1
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• 2008