• Journal of Microbiology and Biotechnology
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• 제29권1호
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• pp.141-150
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• 2019

The spatial landmark protein Bud8 plays a crucial role in bipolar budding in the budding yeast Saccharomyces cerevisiae. The unconventional yeast Yarrowia lipolytica can also bud in a bipolar pattern, but is evolutionarily distant from S. cerevisiae. It encodes the protein YALI0F12738p, which shares the highest amino acid sequence homology with S. cerevisiae Bud8, sharing a conserved transmembrane domain at the C-terminus. Therefore, we named it YlBud8. Deletion of YlBud8 in Y. lipolytica causes cellular separation defects, resulting in budded cells remaining linked with one another as cell chains or multiple buds from a single cell, which suggests that YlBud8 may play an important role in cell separation, which is distinct from the function of Bud8 in S. cerevisiae. We also show that the YlBud8-GFP fusion protein is located at the cell membrane and enriched in the bud cortex, which would be consistent with a role in the regulation of cell separation. The coiled-coil domain at the N-terminus of YlBud8 is important to the correct localization and function of YlBud8, as truncated proteins that do not contain the coiled-coil domain cannot rescue the defects observed in $Ylbud8{\Delta}$. This finding suggests that a new signaling pathway controlled by YlBud8 via regulation of cell separation may exist in Y. lipolytica.

• Journal of Animal Science and Technology
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• 제46권3호
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• pp.495-502
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• 2004

장출혈성대장균 O157:H7의 eae유전자 산물인 intimin은 장 상피세포의 부착성을 조절하는 단백질로 알려져 있다. Intimin의 C-말단 아미노산 잔기와(His)$_6$이 혼합되어 이루어진 plasmid를 작성하여 재조합 단백질(34kDa)을 발현시켰다. 발현된 재조합 intimin 단백질의 면역원성을 확인하기 위해 토끼와 산란계에서 항혈청 및 난황항체(IgY)를 제조하였다. O157:H7에서 분리한 세포외막단백질(OMPs)과 제조된 항혈청과의 western blot상의 반응에서 약 94kDa의 위치에서 양성반응을 보여 발현된 재조합 단백질의 면역원성 효과가 확인되었다. 면역원성이 확인된 단백질을 산란계에 면역한 결과, 면역 후 4${\sim}$6주 경부터 높은 수준의 항체가 형성되었다. 재조합 intimin 단백질에 대한 난황 항체의 항원결합능력 조사를 위하여 중화반응시험을 수행한 결과, 재조합 intimin 단백질에 대한 난황 항체가 O157:H7과 강하게 결합하는 것으로 나타났다. 따라서 본 연구에서 발현된 재조합 intimin 단백질은 토끼와 산란계의 면역반응을 유도할 수 있는 효율적인 면역원임과 동시에 난황 항체 생산을 위한 항원으로의 이용가능성이 확인되었다.

• 생명과학회지
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• 제14권2호
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• pp.315-319
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• 2004

사람의 serine palmitoyltransferase(SPT, EC 2.3.1.50)에 대한 항체를 제작하기 위하여 E. coli발현 vector인 pRset vector에 SPTLC1 및 SPTLC2 유전자를 subcloning하고 BL21 (DE3)pLys cell에 발현시켰다. 포유동물의 SPT는 원핵세포의 SPT homodimer와는 달리 SPTLC1 및 SPTLC2 2개의 sub-unit로 된 heterodimer이다. Human embryo kidney cell인 HEK293 cell의 total RNA로부터 RT-PCR을 행하여 cDNA library를 얻은 다음 SPTLC1 및 SPTLC2의 특이적인 primer 들을 이용하여 PCR을 행하였다. SPTLC1 및 SPTLC2 DNA를 hexahistidine fusion 단백질을 발현시킬 수 있는 pRset vector에 cloning하여 pRsetB/SPTLC1 및 pRsetA/SPTLC2를 얻고 염기서열을 확인하였다. 재조합 plasmid를 발현세포인 BL21 cell에 형질전환시킨 다음 ampicillin 및 chroramphenicol 배지에서 선별하여 재조합세포를 얻었다. 1 mM IPTG로서 발현을 유도하였으며 세포 단백질을 SDS-PAGE로 분리한 다음 His-tag antibody로 western blotting을 행하여 SPTLC 및 SPTLC2가 발현되었음을 확인하였다.

• Journal of Nutrition and Health
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• 제29권9호
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• pp.971-980
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• 1996

The soluble transferrin receptor(TfR) in human serum has been shown recently to be a truncated form of intact membrane bound receptor containing most of the extracellular domain. We purfied the transferin-free TfR from human serum by immounoaffinity chromatography which produced the single protein identity in high resolution gel chormatography. The monoclonal antibodies(MAb) against purifed serum TfR were produced by fusion of spleen cells o fimmunized Balb/c mice and SP2 cells. Ten hybrids producing MAb specific for serum TfR were identifed and determine their iostypes. A immunoraddiometric assay (IRMA) for serum TfR was established using two monoclonal IgG1 antibodies as the coating and indicator antibodies on the bosis of their suitability in sandwich IRMA of serum TfR. The mean serum TfR levels in the 15 normal male, 15 normal female, and 19 iron-deficient subjects were 5.4$\pm$0.98, 4.6$\pm$0/76, and 18.0$\pm$12.8mg/1, respectively, and the difference in mean values between normal and iron deficient subjects was significant(p=0.0005). There existed the inverse logarithmic relationship(r=-0.9336, p<0.0001) between the serum TfR and ferritin levels.

• Molecules and Cells
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• 제43권4호
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• pp.313-322
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• 2020

Eukaryotes transport biomolecules between intracellular organelles and between cells and the environment via vesicle trafficking. Soluble N-ethylmaleimide-sensitive factor attachment protein receptors (SNARE proteins) play pivotal roles in vesicle and membrane trafficking. These proteins are categorized as Qa, Qb, Qc, and R SNAREs and form a complex that induces vesicle fusion for targeting of vesicle cargos. As the core components of the SNARE complex, the SNAP25 Qbc SNAREs perform various functions related to cellular homeostasis. The Arabidopsis thaliana SNAP25 homolog AtSNAP33 interacts with Qa and R SNAREs and plays a key role in cytokinesis and in triggering innate immune responses. However, other Arabidopsis SNAP25 homologs, such as AtSNAP29 and AtSNAP30, are not well studied; this includes their localization, interactions, structures, and functions. Here, we discuss three biological functions of plant SNAP25 orthologs in the context of AtSNAP33 and highlight recent findings on SNAP25 orthologs in various plants. We propose future directions for determining the roles of the less well-characterized AtSNAP29 and AtSNAP30 proteins.

• 한국미생물학회:학술대회논문집
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• 한국미생물학회 2000년도 추계학술발표대회
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• pp.24-31
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• 2000

In order to find out SoxR-reducing system in E. coli, we generated Tn10-insertion mutants and screened for constitutive expression of SoxS in a soxS-lacZ fusion strain. One mutation was mapped in rseB, a gene in rseABC (Regulation of SigmaE) operon. The constitutive soxS-expressing phenotype was due to the polar effect on the downstream gene, rseC. RseC is likely to function as a component of SoxR reduction system because SoxR was kept in oxidized form to activate soxS expression in rseC mutant. RseC is an integral membrane protein with an N-terminal cysteine-rich domain in the cytoplasm. The functionally critical cysteines were determined by substitution mutagenesis. The truncated N-terminal domain of RseC reduced the soxS transcription by $50\%$ as judged by in vitro transcription assay. Currently RseC is believed to be a reducing factor for SoxR. However, the mechanism for the reduction needs further investigation.

• Archives of Pharmacal Research
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• 제18권2호
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• pp.113-117
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• 1995

We re-cloned mouse ${\delt}-Opioid$receptor from NG108-15 cells using RT-PCR, and confirmed it by restriction analysis and by sequencing the beginning and end part of the amplified DNA. When transiently expressed in COS-7 cells, cloned ${\delt}-Opioid$ receptor showed saturable and specific binding to $[^3H]$naloxone with very similar binding parameters to originally reported ones. To make antibodies specific for the ${\delt}-Opioid$ receptor, the carboxy tail of the receptor, which is unique to the ${\delt}-Opioid$ receptor compared with other opioid receptors, was expressed in bacteria as a ufsion proteinwith glutathione S-transferase. Purified fusion protein selective for ${\delt}-Opioid$ receptor when tested by western blotting using membrane proteins prepared from transfected COS-7 cells. Cloned ${\delt}-Opioid$ receptor andl antibodies specific for ${\delt}-Opioid$ receptor are going to be valuable tools for studying pharmacological actions of the ${\delt}-Opioid$ receptor and morphine dependence.

• Biomolecules & Therapeutics
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• 제22권2호
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• pp.114-121
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• 2014

Refractoriness of acute myeloid leukemia (AML) cells to chemotherapeutics represents a major clinical barrier. Suicide gene therapy for cancer has been attractive but with limited clinical efficacy. In this study, we investigated the potential application of herpes simplex virus thymidine kinase/ganciclovir (HSV-TK/GCV) based system to inhibit chemoresistant AML cells. We first generated Ara-C resistant K562 cells and doxorubicin-resistant THP-1 cells. We found that the HSV-TK/GCV anticancer system suppressed drug resistant leukemic cells in culture. Chemoresistant AML cell lines displayed similar sensitivity to HSV-TK/GCV. Moreover, HSV-TK/GCV killing of leukemic cells was augmented to a mild but significant extent by all-trans retinoic acid (ATRA) with concomitant upregulation of Connexin 43, a major component of gap junctions. Interestingly, HSV-TK/GCV killing was enhanced by expression of vesicular stomatitis virus G glycoprotein (VSV-G), a fusogenic membrane protein, which also increased leukemic cell fusion. Co-culture resistant cells expressing HSV-TK and cells stably transduced with VSV-G showed that expression of VSV-G could promote the bystander killing effect of HSV-TK/GCV. Furthermore, combination of HSV-TK/GCV with VSV-G plus ATRA produced more pronounced antileukemia effect. These results suggest that the HSV-TK/GCV system in combination with fusogenic membrane proteins and/or ATRA could provide a strategy to mitigate the chemoresistance of AML.

• Journal of Microbiology and Biotechnology
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• 제24권6호
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• pp.854-861
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• 2014

The diagnosis of Brucella abortus is mainly based on serological methods using antibody against LPS, which has diagnostic problems. Therefore, to solve this problem, we evaluated two proteins of B. abortus, Cu/Zn superoxide dismutase (SodC) and outer membrane proteins 2b porin (Omp2b). The genes were cloned and expressed in a pMAL system, and the recombinant proteins, rOmp2b and rSodC, were purified as fusion forms with maltose-binding protein. The identity of the proteins was confirmed by SDS-PAGE and Western blot analysis with sera of mice infected with B. abortus. Production of cytokines and nitric oxide (NO) was investigated in RAW 264.7 cells and mouse splenocytes after stimulation with the proteins. Moreover, cellular and humoral immune responses were investigated in BALB/c mice after immunization with the proteins. TNF-${\alpha}$, IL-6, and NO were significantly inducible in RAW 264.7 cells. Splenocytes of naive mice produced IFN-${\gamma}$ and IL-4 significantly by stimulation. Moreover, number of IgG, IFN-${\gamma}$, and IL-4 producing cells were increased in immunized mice with the two proteins. Production of IgG and IgM with rOmp2b was higher than those with rSodC in immunized mice. These results suggest that the two recombinant proteins of B. abortus may be potential LPS-free proteins for diagnosis.

• Biotechnology and Bioprocess Engineering:BBE
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• 제7권5호
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• pp.303-310
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• 2002

Cell therapy applied to wound healing or tissue regeneration presents a revolutionary realm to which principles of gene engineering and delivery may be applied. One promising application is the transplantation of cells into the wounded tissue to help the tissue repair. However, when cells are transplanted from in vitro to in vivo, immune rejection occurs due to the immune response triggered by the activation of T-cell, and the transplanted cells are destroyed by the attack of activated T-cell and lose their function. Immune suppressant such as FK506 is commonly used to suppress immune rejection during transplantation. However, such kind of immune suppressants not only suppresses immune rejection in the periphery of transplanted cells but also suppresses whole immune response system against pathogenic infection. In order to solve this problem, we developed a method to protect the desired cells from immune rejection without impairing whole immune system during cell transplantation. Previously, we reported the success of constructing glomerular epithelial cells for removal of immune complex, in which complement receptor of type 1 (CR1) was over-expressed on the membrane of renal glomerular epithelial cells and could bind immune complex of DNA/anti-DNA-antibody to remove immune complex through phagocy-tosis [1]. Attempting to apply the CR1-expressing cells to cell therapy and evade immune rejection during cell transplantation, we constructed three plasmids containing genes encoding a soluble fusion protein of cytolytic T lymphocyte associated antigen-4 (CTLA4Ig) and an enhanced green fluorescent protein (EGFP). The plasmids were transfected to the above-mentioned glomerular epithelial cells to express both genes simultaneously. Using the clone cells for cell transplantation showed that mice with autoimmune disease prolonged their life significantly as compared with the control mice, and two injections of the cells at the beginning of two weeks resulted in remarkable survivability, whereas it requires half a year and 50 administrations of proteins purified from the same amount of cells to achieve the same effect.