• Asian-Australasian Journal of Animal Sciences
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• 제22권5호
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• pp.712-720
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• 2009

The goal of this study was to elucidate the expression and segmental distribution of the glomerular cationic amino acid metabolism transporter-2 (CAT-2) and thus to improve our understanding of porcine cationic amino acid transporters and amino acid absorption. Porcine CAT-2 was cloned, sequenced and characterized. The predicted amino acid sequence of porcine CAT-2 shared 86.1% and 92.1% identity with human and mouse CAT-2A, respectively. The tissue distribution patterns and ontogenic changes of CAT-2 mRNAs were determined by real-time Q-PCR. The results showed that porcine CAT-2 was highly expressed in the heart and intestinal tract (duodenum, ileum and jejunum). In addition, the mRNA of CAT-2 was found in liver, lung, kidney, brain and muscle. Within the intestinal tract, CAT-2 mRNA was most abundant in the ileum and rarely expressed in the duodenum. In the duodenum, the levels of CAT-2 mRNA reached their peak on day 7 (p<0.05) while in the jejunum, levels were low on day 1 and 7 and increased rapidly after day 26 before peaking on days 30 and 60 (p<0.05). The levels then dramatically decreased by day 90 (p<0.05). In the ileum, levels achieved their maximum on day 30 and then decreased significantly on day 60 (p<0.05).

• 한국식품영양과학회지
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• 제32권5호
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• pp.758-763
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• 2003

구강 편평 세포암종 KB 세포를 이용하여 아미노산 수송계 L억제제인 BCH의 세포 성장억제에 미치는 효과를 밝히기 위해, KB세포에서 uptake실험, MTT분석 및 DNA frag-mentation분석 등을 시행하여 다음과 같은 결과를 얻었다. KB 세포에서는 아미노산 수송계 L 중에서 LAT1과 그 보조인자 4F2hc를 통해 BCH및 중성 아미노산들이 수송되었다. BCH는 시간과 농도에 의존적으로 KB세포의 성장을 억제시켰다. BCH를 처리한 실험군에서 DNA fragmentation 현상은 볼 수 없었다. 본 연구의 결과로서 구강암 세포주인 구강 편평세포암종 KB 세포에서 LAT1과 그 보조인자 4F2hc를 통해 BCH및 중성 아미노산의 수송이 이루어지고 있다는 것을 확인할 수 있었으며 BCH는 이 LAT1을 차단하여 중성 아미노산들의 세포 내 고갈을 유도함으로서 KB 세포 성장의 억제를 유도하는 것으로 사료된다.

• Asian-Australasian Journal of Animal Sciences
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• 제23권2호
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• pp.272-278
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• 2010

In this study, we cloned, sequenced and characterized porcine y+L Amino Acid Transporter-1 (y+LAT1). By screening a translated EST database with the protein sequence of the human $y^{+}$LAT1 and by using rapid amplification of cDNA ends (RACE), the full-length cDNA encoding porcine $y^{+}$LAT1 was isolated from porcine intestine RNA. It was 2,111 bp long, encoding a 511 amino acid trans-membrane glycoprotein composed of 12 transmembrane domains. The predicted amino acid sequence was found to be 91%, 90%, 87% and 87% identical to those of cattle, human, mouse and rat $y^{+}$LAT1 respectively. Real-time RT-PCR results indicated that the small intestine had the highest $y^{+}$LAT1 mRNA abundance and the lung had the lowest $y^{+}$LAT1 mRNA abundance. Baby hamster kidney (BHK) cells transfected with green fluorescent protein (GFP) tagged porcine $y^{+}$LAT1 cDNA indicated that the cellular localization of the gene product in BHK was on the plasma membrane.

• Biomolecules & Therapeutics
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• 제10권2호
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• pp.78-84
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• 2002

Taurine (2-ethaneaminosulfonic acid, $^+{NH}_3{CH_2}{CH_2}{SO_3^{-}}$) is endogenous amino acid with functions as modulator of osmoregulation, antioxidation, detoxification, transmembrane calcium transport, and a free radical scavenger in mammalian tissues. Taurine transporter(TAUT) contains 12 transmembrane helices, which are typical of the $Na^+$- and $Cl^-$-dependent transporter gene family, and has been cloned recently from several species and tissues. To analyze the expression of TAUT mRNA, one step RT-PCR was performed from human and mouse cultured cell lines and from various mouse tissues. The primers were designed to encode highly conserved amino acid sequences at the second transmembrane domain and at the fourth and fifth intracellular domains. RT-PCR analysis showed both of the human intestine HT-29 and mouse macrophage RAW264.7 cell lines expressed mRNA of TAUT. To define the expression patterns of the TAUT mRNA in the murine organs, RT-PCR was performed to detect cDNA representing TAUT mRNA from seven different mouse tissues. The TAUT was detected in all of the mouse tissues analyzed such as heart, lung, thymus, kidney, liver, spleen and brain. A large amount of transcript was fecund from heart, liver, spleen, kidney, and brain, while lung contained a very small amount of transcript.

• 한국식품영양과학회지
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• 제31권5호
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• pp.775-781
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• 2002

hTATl에 의해 수송되는 방향족 아미노산들의 수송특성을 밝히기 위해 hTATl의 cRNA를 미세주입한 Xenopus laevis oocyte에서 hTATl에 의 해 유도되는 방향족 아미노산의 up-take를 여러 조건 하에서 관찰하였긴. hTATl은 L-[$^{14}$ C]tryp-tophan의 uptake를 유도하였으며, 그 uptake는 $Na^{+}$-과 Cl$^{-}$-비 의존적이었다. hTATl은 L-($^{14}$ C)tryptophan의 uptake를 시간의 존적으로 유도함을 알 수 있었다. hTATl에 의한 L-($^{14}$ C) tryptophan의 uptake는 방향족 아미노산인 phenylalanine, tyrosine 및 tryptophan에 의해서 억제되었으며 , hTATl에 의한 아미노산들의 uptake 실험에서 L-($^{14}$ C)phenylalanine, L-($^{14}$ C)tyrosine 및 L-($^{14}$ C)tryptophan의 수송을 확인하였다 hTATl에 의 한 L-($^{14}$ C)tryptophan의 uptake는 포화되었으며, Km치는 452.2$\pm$27.8 UM, V$_{max}$ 값은 2.1 $\pm$0.3 pmol/oocyte/min 이었다. L-($^{14}$ C)tyrosine 및 L-[$^{14}$ C]phenylalanine의 Km치는 각각 636.3$\pm$59.4 UM과 740.5$\pm$96.7 HM이었다. 실험용액의 pH 5.5에서 8.5까지의 변화는 hTATl에 의한 L-[$^{14}$ C]tfpto- phan의 uptake에 별다른 영향을 미치지 못하였다. hTATl의 CRNA를 미 세주입한 oocyte에서 배양시간 의존적 인 L-($^{14}$ C) tryptophan의 efflux를 볼 수 있었으며, 이 efflux는 oocyte 외 용액의 tryptophan존재 유무에는 영향을 받지 않았다. 따라서 본 연구의 결과로 hTATl이 상피세포로부터 혈류로의 방향족 아미노산의 수송에 중요한 역할을 할 것으로 사료된다.

• 약학회지
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• 제43권6호
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• pp.743-750
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• 1999

Human and bovine dopamine transporters (DAT) demonstrate discrete functional differences in the dopamine (DA) transport and cocaine binding. The functional analyses on the chimeras of human and bovine DAT have revealed that the region from the $133^{rd}{\;}to{\;}186^{th}$ residue(encompassing the $3^{rd}$ trans-membrane domain (TM) is responsible for the substrate transport and cocaine binding. The present studies have been done to find out the specific amino acid(s) which is essential for the binding of cocaine to DAT by interchanging the amino acids in that region between human and bovine DAT. When isoleucine, the $152^{nd}$ residue of chimera B3 (bovine DAT sequence) was transformed back to valine, the human DAT residue at the identical position, the cocaine binding was remarkably recovered to 98% of the human DAT values. In addition, the cocaine binding of the human DAT was decreased by 57% by substituting isoleucine for valine at position 152. When isoleucine at position 152 of the chimera B3 was converted to the other amino acids to provide an possible molecular basis for the functional role of the $152^{nd}$ residue, only the conversion to alanine among acids tested significantly the cocaine by 34%, but these effect were not as much as those by the conversion to valine. In conclusion, valine at position 152 is a crucial amino acid for the interaction of cocaine to the DAT.

• 한국미생물·생명공학회지
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• 제34권1호
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• pp.15-22
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• 2006

Ochrobactrum anthropi JW-2의 염색체 DNA로부터 paraquat 내성 유전자 pqrA를 포함하는 4,971 bp의 DNA 염기서열을 결정하였다. 염기서열 분석 결과 2개의 불완전한 ORF(orf1, orf5)와 4개의 완전한 ORF(orf2, pqrA, orf3, orf4)가 존재하는 것으로 나타났는데 orf1, pqrA, orf4, orf5는 direct strand에 orf2와 orf3은 reverse complementary strand 존재하였다. Orf1은 개시코돈이 결손된 불완전한 서열로서, response regulator receiver의 ATP binding region과 상동성을 나타내었다. Orf2는 tetR family에 속하는 transcription repressor와 높은 상동성을 나타내었고 H-T-H motif가 존재하는 것으로 나타났다. 따라서 orf2가 pqrA 유전자의 전사조절에 관여하는 repressor로 추정되어 pqrR2로 명명하였다. Orf3은 lysR type의 transcription activator와 높은 상동성을 나타내었고 N-terminal 부위에 H-T-H motif와 C-terminal 부위에 substrate binding domain이 존재하는 것으로 나타났다. 따라서 orf3은 pqrA의 전사조절에 관여하는 transcription activator로 추정되어 pqrR1로 명명하였다. Orf4는 amino acid ABC transporter의 periplasmic amino acid-binding protein과 상동성을 나타내었으며, orf5는 종결 코돈이 없는 불완전한 ORF로서 amino acid ABC transporter의 permease protein과 상동성을 나타내었다. 이와 같은 결과로 미루어 pqrA 유전자 주위에 존재하는 전사조절 유전자들이 paraquat 내성유전자인 pqrA의 발현조절을 통하여 paraquat에 대한 내성획득에 관여하는 것으로 판단되었다.

• 한국응용약물학회:학술대회논문집
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• 한국응용약물학회 1998년도 Proceedings of UNESCO-internetwork Cooperative Regional Seminar and Workshop on Bioassay Guided Isolation of Bioactive Substances from Natural Products and Microbial Products
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• pp.156-157
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• 1998

Taurine is synthesized in the body or uptaken from dietary and is distributed in the various organs. It differs from other amino acids by virtue of the fact that a sulfonic acid group replaces the carboxyl group of what would be ${\beta}$-alanine. In order to function within the cell it must be transported into the cells by taurine transporter that is spanned 12 transmembrane domains. The human taurine transporter has long cytoplasmic carboxy and amino termini that may function as regulatory attachment sites for other proteins. Six potential protein kinase C(PKC) phosphorylation sites have been reported in human taurine transporter.

• Journal of Periodontal and Implant Science
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• 제36권3호
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• pp.783-796
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• 2006

The periodontium is a topographically complex organ consisting of epithelial tissue, soft and mineralized tissues. Structures comprising the periodontium include the gingiva, periodontal ligament (PDL) , cementum and the alveolar bone. The molecular mechanism of differentiation in PDL fibroblast cells remain unclear. Amino acid transporters play an important role in supplying nutrition to normal and cancer cells and for cell proliferation. Amino acid transport system L is a major nutrient transport system responsible for the Na+-independent transport of neutral amino acids including several essential amino acids. The system L is divided into two major subgroups, the L-type amino acid transporter 1 (LAT1) and the L-type amino acid transporter 2 (LAT2). In this study, the expression pattern of amino acid transport system L was, therefore, investigated in the differentiation of PDL fibroblast cells. To determine the expression level of amino acid transport system L participating in intracellular transport of amino acids in the differentiation of PDL fibroblast cells, it was examined by RT-PCR, observation of cell morphology, Alizaline red-S staining and uptake analysis after inducing experimental differentiation in PDL fibroblast cells isolated from mouse molar teeth. The results are as follows. 1. The LAT1 mRNA was expressed in the early stage of PDL fibroblast cell differentiation. This expression level was gradually reduced by differentiation- inducing time and it was not observed after the late stage. 2. The expression level of LAT2 mRNA was increased in time-dependent manner during differentiation induction of PDL fibroblast cells. 3. There was no changes in. the expression level of 4F2hc mRNA, the cofactor of LAT1 and LAT2, during differentiation of PDL fibroblast cells. 4. The expression level of ALP mRNA was gradually increased and the expression level of Col I mRNA was decreased during differentiation of PDL fibroblast cells. 5. The L-leucine transport was reduced by time from the early stage to the late stage in PDL fibroblast cell differentiation. As the results, it is considered that among neutral ammo acid transport system L in differentiation of PDL fibroblast cells, the LATl has a key role in cell proliferation in the early stage of cell differentiation and the LAT2 has an important role in the late stage of cell differentiation for providing cells with neutral amino acids including several essential amino acids.

• Asian-Australasian Journal of Animal Sciences
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• 제21권8호
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• pp.1134-1142
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• 2008

Cationic amino acid transporter $b^{0,+}AT$ (HGMW-approved gene symbol SLC7A9, solute carrier family 7, member 9) plays a crucial role in amino acid nutrition. In the present study, we describe the cloning and sequencing of porcine $b^{0,+}AT$. Based on the sequence of porcine $b^{0,+}AT$ deposited in the NCBI (National Center for Biotechnological Information), we identified a putative porcine homologue. Using rapid amplification of cDNA ends (RACE), the full-length cDNA encoding porcine $b^{0,+}AT$ was isolated. The porcine $b^{0,+}AT$ cDNA was 1,680 bp long, encoding a 487 amino acid trans-membrane protein. The predicted amino acid sequence was found to have 88.9% and 87.1% identity with human and mouse $b^{0,+}AT$, respectively. Real-time RT-PCR indicated porcine $b^{0,+}AT$ transcripts expressed in heart, kidney, muscle and small intestine. The small intestine had the highest $b^{0,+}AT$ mRNA abundance while the muscle had the lowest (p<0.05). Along the longitudinal axis, the ileum had the highest $b^{0,+}AT$ mRNA abundance while the colon had the lowest (p<0.05). The $b^{0,+}AT$ mRNA level was highest on day 7 and 90 in the duodenum (p<0.05). It increased from day 1 to day 26 in the jejunum (p>0.05) and had the highest abundance on day 60 (p<0.05). There was, however, no difference between day 1, 7, 26, 30, 90 and 150 (p>0.05). The strongest $b^{0,+}AT$ expression appeared on day 7 in the ileum before weaning, and then decreased till day 30 but rose gradually again from day 60 to 150 (p<0.05).