• BMB Reports
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• 제56권2호
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• pp.108-113
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• 2023

Cohesin is a ring-shaped protein complex that comprises the SMC1, SMC3, and α-kleisin proteins, STAG1/2/3 subunits, and auxiliary factors. Cohesin participates in chromatin remodeling, chromosome segregation, DNA replication, and gene expression regulation during the cell cycle. Mitosis-specific α-kleisin factor RAD21 and meiosis-specific α-kleisin factor REC8 are expressed in embryonic stem cells (ESCs) to maintain pluripotency. Here, we demonstrated that RAD21 and REC8 were involved in maintaining genomic stability and modulating chromatin modification in murine ESCs. When the kleisin subunits were depleted, DNA repair genes were downregulated, thereby reducing cell viability and causing replication protein A (RPA) accumulation. This finding suggested that the repair of exposed single-stranded DNA was inefficient. Furthermore, the depletion of kleisin subunits induced DNA hypermethylation by upregulating DNA methylation proteins. Thus, we proposed that the cohesin complex plays two distinct roles in chromatin remodeling and genomic integrity to ensure the maintenance of pluripotency in ESCs.

• The Plant Pathology Journal
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• 제35권3호
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• pp.243-256
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• 2019

Field surveys for Plum pox virus (PPV) infection were conducted in stone fruit orchards all over Bulgaria. In total, 1168 out of 3020 leaf samples from cultivated Prunus spp. and wildly growing P. cerasifera trees reacted positive for PPV in DASI-ELISA with the universal monoclonal antibody (MAb) 5B. Further ELISA analyses showed that 987 and 127 isolates belonged to PPV-M and PPV-D serotypes, respectively. The plum and P. cerasifera showed 82.0% and 50.5% levels of infection, respectively followed by the peach (40.0%) and the apricot (32.0%). Five hundred fifty one PPV isolates were further typed by IC-RT-PCR with PPV-Rec, -M and -D-specific primers, targeting (Cter)NIb-(Nter) CP genome region, as 125 isolates were sequenced. The results revealed the presence of PPV-Rec, PPV-M and PPV-D and mixed infections of these strains. PPV-Rec was the most prevalent strain (49.0%), followed by PPV-M (40.1%), while PPV-D was the less spread strain (8.2%). PPV-Rec was the most common strain in plums, including the eight "old-aged" trees from the region of the first Sharka discovery. PPV-M was the most prevalent strain in peach and apricot. Phylogenetic analyses on (Cter)NIb-(Nter)CP of the isolates were performed. PPV-Rec isolates formed a homogeneous group, while PPV-M isolates split into PPV-Ma and PPV-Mb subgroups. Five separated clades were formed by the analyzed PPV-D isolates. Nucleotide sequences of the partial CP coding region of the analyzed isolates revealed a slightly higher intra-strain genetic variability in PPV-Rec and PPV-M isolates, while that of PPV-D strain isolates was higher from the reported for these strains.

• Reproductive and Developmental Biology
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• 제34권1호
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• pp.33-40
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• 2010

Equine chorionic gonadotropin (eCG) is a heavily glycosylated glycoprotein composed of non-covalently linked $\alpha$- and $\beta$-subunits. To study the function and signal transduction of tethered recombinant-eCG (rec-eCG), a single chain eCG molecule was constructed, and the rec-eCG protein was prepared. In this study, we constructed 5 mutants (${\Delta}1$, ${\Delta}2$, ${\Delta}3$, ${\Delta}4$, and ${\Delta}5$) of rec-eCG using data about known glycoprotein hormones to analyze the role of specific follicle stimulating homone (FSH)-like activity. Three amino acids of certain specific sites were replaced with alanine. The expression vectors were transfected into CHO cells and subjected to G418 selection for 2~3 weeks. The media were collected and the quantity of secreted tethered rec-eCGs was quantified by ELISA. The LH- and FSH-like activities were assayed in terms of cAMP production by rat LH/CG and rat FSH receptors. Then, the metabolic clearance rate analyzed by the injection of rec-eCG (5 IU) into the tail vein was analyzed. The mutant eCGs (${\Delta}l$, ${\Delta}4$, and ${\Delta}5$) were transcripted, but not translated into proteins. Rec-eCG A2 was secreted in much lower amounts than the wild type. Only the rec-eCG ${\Delta}3$ ($\beta$-subunit: $Gln^{94}-Ile^{95}-Lys^{96}{\rightarrow}Ala^{94}-Ala^{95}-Ala^{96}$) was efficiently secreted. Although activity is low, its LH-like activity was similar to that of tethered $eCG{\beta\alpha}$. However, the FSH-like activity of rec-$eCG{\beta\alpha\Delta}3$ was completely flat. The result of the analysis of the metabolic clearance rate shoed the persistence of the mutant in the blood until 4 hours after the injection. After then, it almost disappeared at 8 hours. Taken together, these data suggest that 94~96 amino acid sequences in eCG $\beta$-subunit appear to be of utmost importance for signal transduction of the FSH receptor.

• Journal of Microbiology and Biotechnology
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• 제27권9호
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• pp.1701-1710
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• 2017

Classical swine fever virus (CSFV) is the etiologic agent of classical swine fever, a highly contagious disease that causes significant economic losses to the swine industry. The lapinized C-strain, a widely used vaccine strain against CSFV, has low growth efficiency in cell culture, which limits the productivity in the vaccine industry. In this study, a recombinant virus derived from C-strain was constructed and subjected to continuous passaging in PK-15 cells with the goal of acquiring a high progeny virus yield. A cell-adapted virus variant, RecCpp80, had nearly 1,000-fold higher titer than its parent C-strain but lost the ability to induce fever in rabbits. Sequence analysis of cell-adapted RecC variants indicated that at least six nucleotide changes were fixed in RecCpp80. Further adaption of RecCpp80 variant in swine testicle cells led to a higher virus yield without additional mutations. Introduction of each of these residues into the wild-type RecC backbone showed that one mutation, M979R (T3310G), located in the C-terminal region of E2 might be closely related to the cell-adapted phenotype. Rabbit inoculation revealed that $RecCpp40_{+10}$ failed to induce fever in rabbits, whereas $RecCpp80_{+10}$ caused a fever response similar to the commercial C-strain vaccine. In conclusion, the C-strain can be adapted to cell culture by introducing specific mutations in its E2 protein. The mutations in RecCpp80 that led to the loss of fever response in rabbits require further investigation. Continuous passaging of the C-strain-based recombinant viruses in PK-15 cells could enhance its in vitro adaption. The non-synonymous mutations at 3310 and 3531 might play major roles in the enhanced capacity of general virus reproduction. Such findings may help design a modified C-strain for improved productivity of commercial vaccines at reduced production cost.

• Journal of Microbiology and Biotechnology
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• 제31권7호
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• pp.912-920
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• 2021

SOS response is a conserved response to DNA damage in prokaryotes and is negatively regulated by LexA protein, which recognizes specifically an "SOS-box" motif present in the promoter region of SOS genes. Myxococcus xanthus DK1622 possesses a lexA gene, and while the deletion of lexA had no significant effect on either bacterial morphology, UV-C resistance, or sporulation, it did delay growth. UV-C radiation resulted in 651 upregulated genes in M. xanthus, including the typical SOS genes lexA, recA, uvrA, recN and so on, mostly enriched in the pathways of DNA replication and repair, secondary metabolism, and signal transduction. The UV-irradiated lexA mutant also showed the induced expression of SOS genes and these SOS genes enriched into a similar pathway profile to that of wild-type strain. Without irradiation treatment, the absence of LexA enhanced the expression of 122 genes that were not enriched in any pathway. Further analysis of the promoter sequence revealed that in the 122 genes, only the promoters of recA2, lexA and an operon composed of three genes (pafB, pafC and cyaA) had SOS box sequence to which the LexA protein is bound directly. These results update our current understanding of SOS response in M. xanthus and show that UV induces more genes involved in secondary metabolism and signal transduction in addition to DNA replication and repair; and while the canonical LexA-dependent regulation on SOS response has shrunk, only 5 SOS genes are directly repressed by LexA.

• 한국생물공학회:학술대회논문집
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• 한국생물공학회 2000년도 추계학술발표대회 및 bio-venture fair
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• pp.187-190
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• 2000

본 연구는 5가지의 발광성 미생물을 이용하여 유해 방사선으로 알려져 있는 ${\gamma}-rays$가 여러가지 cellular stresses 중, 특히 유전자 손상과 생물막 손상을 유발하였는데, 이들의 손상 정도가 총 방사선량과 상관관계가 있음을 발생하는 bioluminescence 로써 확인하였다. 뿐만 아니라, 선량률의 변화를 통하여 방사선으로 인한 유전자 손상 및 일반적인 독성 효과가 큰 영향을 받는 것을 확인하였는데, 선량률 증가에 따라 이들 손상정도가 증가하는 것으로 보아 선량률이 genetic 및 radioprotecion에 심각한 영향을 미치는 것을 확인하였다.

• The Plant Pathology Journal
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• 제31권2호
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• pp.108-114
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• 2015

Curvularia lunata is an important maize foliar fungal pathogen that distributes widely in maize growing area in China, and several key pathogenic factors have been isolated. An yeast two-hybrid (Y2H) library is a very useful platform to further unravel novel pathogenic factors in C. lunata. To construct a high-quality full length-expression cDNA library from the C. lunata for application to pathogenesis-related protein-protein interaction screening, total RNA was extracted. The SMART (Switching Mechanism At 5' end of the RNA Transcript) technique was used for cDNA synthesis. Double-stranded cDNA was ligated into the pGADT7-Rec vector with Herring Testes Carrier DNA using homologous recombination method. The ligation mixture was transformed into competent yeast AH109 cells to construct the primary cDNA library. Eventually, a high qualitative library was successfully established according to an evaluation on quality. The transformation efficiency was about $6.39{\times}10^5$ transformants/$3{\mu}g$ pGADT7-Rec. The titer of the primary cDNA library was $2.5{\times}10^8cfu/mL$. The numbers for the cDNA library was $2.46{\times}10^5$. Randomly picked clones show that the recombination rate was 88.24%. Gel electrophoresis results indicated that the fragments ranged from 0.4 kb to 3.0 kb. Melanin synthesis protein Brn1 (1,3,8-hydroxynaphthalene reductase) was used as a "bait" to test the sufficiency of the Y2H library. As a result, a cDNA clone encoding VelB protein that was known to be involved in the regulation of diverse cellular processes, including control of secondary metabolism containing melanin and toxin production in many filamentous fungi was identified. Further study on the exact role of the VelB gene is underway.

• 생명과학회지
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• 제17권11호
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• pp.1497-1504
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• 2007

사람의 혈소판조절인자 (TPO)의 분비와 기능을 분석하기 위하여 사람 간 cDNA로부터 TPO cDNA를 분리하여 동물세포에서 재조합체를 생산하였다. 또한, 당쇄의 기능분석을 위하여 6개의 당쇄첨가부위를 Ala으로 치환하여 각각의 돌연변이체 재조합체도 생산하여 이들의 생리활성분석을 위하여 피하주사하여 혈소판의 증가여부를 분석하였으며, 체내 약동학검사를 위하여 꼬리 정맥에 재조합체를 주사하여 24시간까지 혈액을 채취하였다. Wild-type TPO는 효과적으로 분비하였으나, 크로닝에서 분석되어 진 116개 아미노산이 삭제된 돌연변이체는 배양상층으로 분비되지 않았다. N-linked 당쇄첨가 부위는 3번과 4번을 제외하고는 거의 비슷한 발현양상을 나타내었다. 특히 4번당쇄부위는 TPO의 분비에 중요한 역할을 하는 것으로 나타났다. 재조합체 10ng을 피하주사에 의하여 체내 혈소판이 유의적으로 증가하였으며, 5ng을 이용한 약동학 분석결과 1시간에 최대로 증가하였으며 그 이후 급격하게 감소하여 10시간에는 거의 존재하지 않았다. 따라서, 이러한 연구는 고 활성을 가지는 유전자 재조합체 TPO의 생산을 가능하게 하고, 또한 새로운 분자의 TPO를 가능하게 할 것으로 사료된다.

• Preventive Nutrition and Food Science
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• 제7권2호
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• pp.139-145
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• 2002

Hen egg-white lysozyme, ovalbumin, egg-yolk phosvitin, acid-precipitated soy protein and $\alpha$$_{sl}$ milk casein were covalently linked with galactomannan through a controlled dry-heating at 6$0^{\circ}C$ under 79% relative humidity without any chemical reagent. Neoglycosylation by the covalent binding of polysaccharide chains brought a significant improvement into the surface functionalities of food proteins. Excellent emulsifying properties and foaming properties were observed in all protein-galactomannan conjugates. Bacterial mutagenesis tests and animal dose test were done to evaluate the food safety of the protein-galactomannan conjugates. The neo-glycoproteins were negative for Ames test using Salmonella typhimurium TA100 (hisG46) and TA98 (hisD3052) strains, and rec-assay using Bacillus subtilis Hl7 (rec) and M45 (re $c^{+}$) strains. All substances were also nontoxic for oral administration to rats. L $D_{50}$ 's of these substances were all more than 7.5 g/kg body-weight of rat. No effect was also observed in the weight increases and the concentrations of total cholesterol, triglyceride and phospholipids in blood serum of the administrated rats with 7.5 g/kg conjugates. Thus, Maillard-type protein-polysaccharide conjugates prepared by covalent attachment of galactomannan to food proteins were proposed to be useful as a safe functional biopolymer in this study.y.

• 생명과학회지
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• 제27권8호
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• pp.864-872
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• 2017

eCG는 다른 포유동물에서 FSH와 LH의 활성을 나타내기 때문에 성선자극 호르몬 family에서 아주 특이적이고 많은 당쇄가 수식되어진 알파와 베타의 비공유결합으로 구성되어 있다. 유전자 재조합 $eCG{\beta}/{\alpha}$의 생물학적 기능을 규명하기 위하여 말의 LH/CGR의 포유동물발현용 벡터를 구축하였다. 재조합 $eCG{\beta}/{\alpha}$의 활성분석은 말의 LH/CGR가 일시적으로 발현되는 CHO-K1 세포와 지속적으로 발현되는 PathHunter Parental 세포를 이용하여 분석하였다. 유전자 재조합 $eCG{\beta}/{\alpha}$는 CHO-K1 부유세포의 상층으로 효율적으로 분비되었으며, 분비량은 transfection 후 1일에서 7일까지 약 200 mIU/ml이었다. Western blot 분석결과는 재조합 $eCG{\beta}/{\alpha}$의 분자량은 약 40-45 kDa으로 검출되었다. eLH/CGR가 발현되는 CHO-K1 세포에서의 cAMP분비량으로 재조합 $eCG{\beta}/{\alpha}$의 활성을 분석하였다. 그 결과 cAMP농도는 재조합 $eCG{\beta}/{\alpha}$의 농도의존적으로 증가하였다. eLH/CGR가 일시적으로 발현하는 CHO-K1 세포에서 $EC_{50}$ 값은 $8.1{\pm}6.5ng$이었다. 또한 일시적 및 지속적으로 eLH/CGR가 발현하는 PathHunter Parental 세포에서도 재조합 $eCG{\beta}/{\alpha}$의 LH 활성 분석결과 높은 활성을 나타내는 것으로 확인되었으며, 이들의 $EC_{50}$ 값은 각각 $5.0{\pm}4.7ng/ml$, $4.5{\pm}5.2ng/ml$으로 나타났다. 따라서 이러한 결과에 의하면 재조합 $eCG{\beta}/{\alpha}$는 말의 LH/CGR가 발현하는 세포에서 생물학적 활성을 나타난다는 것을 확인하였으며, PathHunter Parental 세포에서 지속적으로 발현되는 세포의 확보는 당쇄제거에 의한 재조합 eCG의 돌연변이등에 관한 기능적인 메커니즘을 밝히는데 유용할 것으로 사료된다.