The aim of the present study was to delineate the expression and secretion of insulin-like growth factor (IGF) system components by pig liver cells.Hepatocytes were prepared from 3-wk-old weanling piglets following a two-step collagenase perfusion procedure, after which the cells were incubated for 24 or 48 h at a density of 2×10 5 cells per 35-mm dish in 2-ml Williams' medium E. The cells were found to express the genes encoding IGF-I, IGF-binding proteins (IGFBPs)-2 and -3 and acid-labile subunit (ALS) by reverse transcription-polymerase chain reaction (RT-PCR) following the culture.However, IGF-I was localized to hepatocytes by immunohistochemical analysis, whereas IGFBP-3 was localized to endothelial cells, but not to hepatocytes.This indicated that the IGFBP-3 gene expression detected by RT-PCR was likely to have been contributed by unidentified non-parenchymal cells that had not been removed during the hepatocyte preparation.The conditioned culture medium (CCM) of the cells contained immunoreactive IGF-I and IGF-II, with the latter being seven-fold more abundant than the former.The CCM also contained 43-, 40-, 34-, 31-kDa doublet and 26-kDa IGFBPs as examined by Western ligand blotting.The 40-, 34-and 31-kDa doublet IGFBPs were approximately three-fold as abundant as the 43-and 26-kDa IGFBPs.Moreover, the 43-and 40-kDa doublet and the 34-kDa IGFBPs were immunoprecipitable with IGFBP-3 and IGFBP-2 antibodies, respectively.Overall, these results are similar to those known in the rat, which suggests that the IGF system components are likely to be expressed and secreted in pig liver in a manner similar to that in rat liver.
Since the early 1990s when the first commercialization of living modified organism (LMO), LMO has been developed to improve nutrient quality and productivity of crops. As the self-sufficiency rate of soybean has gradually decreased in South Korea, most of soybeans have been imported. The cultivation and trade of LM crops are regulated in many countries and authorizations for the use are mandatory in most. In South Korea, the cultivation of LM crop is not allowed and unintentional release of LMO into the natural environment is prohibited. In this study, we developed a novel multiplex PCR method for four LM soybean events (CV127, MON87705, FG72 and MON87701) which were approved recently in South Korea. Multiplex PCR primers were designed for PCR amplification of four LMO event-specific fragments, and we analyzed 41 environmental monitoring samples to confirm the efficiency of this method. These results indicated that the multiplex PCR detection method is sufficient for four LM soybeans found in the natural environment. Based on our finding, we suggest that the new technique may be useful as a lead tool for the development of a detection method for various LMO/GMOs.
SA는 천연 페놀 화합물로써 식물체가 생성하는 호르몬 중의 하나이다. SA는 특히 병저항성, 생물학적, 비생물학적 스트레스로 인해 합성이 촉진되며 식물 방어 기작을 일으킨다고 알려져 있다. 식물의 방어 기작은 바로 식물에서 얻어지는 생산량에 영향을 미치기 때문에 SA에 대한 연구가 많이 되어져 왔다. 하지만 SA를 이해하기에는 아직까지 많은 연구가 필요 되어 지고 있다. 따라서 본 연구는 애기장대에서 SA 생합성하는데 중요한 효소인 SID2가 병저항성이 강한 siz1-2 돌연변이체와 야생형에서 어떠한 조절의 차이를 보이는 지를 SID2 promoter에 의해서 조절되는 GUS와 LUC를 가진 각각의 형질전환 식물체를 통하여 관찰하였다. GUS의 발현을 GUS histochemical assay, GUS enzyme assay 그리고 LUC의 발현을 CCD 카메라를 이용한 이미지 촬영과 Luciferase enzyme assay 수행한 결과, siz1-2를 사용한 형질전환 식물체에서 야생형에 비해 발현이 높게 일어났다. 이것을 바탕으로 SA에 반응하는 유전자들의 발현이 siz1-2 돌연변이체에서는 높은 이유가 SID2의 발현이 높게 조절 받기 때문이라는 것을 SID2 promoter:GUS::LUC/siz1-2 형질전환 식물체를 통해 알 수 있었다. Salicylic acid(SA) is a phytohormone that is related to plant defense mechanism. The SA accumulation is triggered by abiotic and biotic stresses. SA acts as a signal molecular compound mediating systemic acquired resistance and hypersensitive response in plant. Although the role of SA has been studied extensively, an understanding of the SA regulatory mechanism is still lacking in plants. In order to comprehend SA regulatory mechanism, we have been transformed with a SID2 promoter:GUS::LUC fusion construct into siz1-2 mutant and wild plant(Col-0). SIZ1 encodes SUMO E3 ligase and negatively regulates SA accumulation in plants. SID2(SALICYLIC ACID INDUCTION DEFICIENT2) is a crucial enzyme of SA biosynthesis. The Arabidopsis SID2 gene encodes isochorismate synthase(ICS) that controls SA level by conversion of chorismate to isochorismate. We compared the regulation of SID2 in wild-type and siz1-2 transgenic plants that express SID2 promoter:GUS::LUC constructs respectively. The expressions of $\beta$-GLUCURONIDASE and LUCIFERASE were higher in siz 1-2 transgenic plant without any stress treatment. SID2 promoter:GUS::LUC/siz1-2 transgenic plant will be used as a starting material for isolation of siz1-2 suppressor mutants and genes involved in SA-mediated stress signaling pathway.
Reversible conjugation of the small ubiquitin modifier (SUMO) peptide to proteins (SUMOylation) plays important roles in cellular processes in animals and yeasts. However, little is known about plant SUMO targets. To identify SUMO substrates in Arabidopsis and to probe for biological functions of SUMO proteins, we constructed 6xHis-3xFLAG fused AtSUMO1 (HFAtSUMO1) controlled by the CaMV35S promoter for transformation into Arabidopsis Col-0. After heat treatment, an increased sumoylation pattern was detected in the transgenic plants. SUMO1-modified proteins were selected after two-dimensional gel electrophoresis (2-DE) image analysis and identified using matrix-assisted laser-desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS). We identified 27 proteins involved in a variety of processes such as nucleic acid metabolism, signaling, metabolism, and including proteins of unknown functions. Binding and sumoylation patterns were confirmed independently. Surprisingly, MCM3 (At5G46280), a DNA replication licensing factor, only interacted with and became sumoylated by AtSUMO1, but not by SUMO1ΔGG or AtSUMO3. The results suggest specific interactions between sumoylation targets and particular sumoylation enzymes.
Abstract SIZ1 (for yeast SAP and MIZ1) encodes the sole ortholog of mammalian PIAS (for protein inhibitor of activated STAT) and yeast SIZ SUMO (for small ubiquitin-related modifier) E3 ligases in Arabidopsis (Arabidopsis thaliana). Four conserved motifs in SIZ1 include SAP (for scaffold attachment factor A/B/acinus/PIAS domain), PINIT (for proline-isoleucine-asparagine-isoleucine-threonine), SP-RING (for SIZ/PIAS-RING), and SXS (for serine-X-serine, where X is any amino acid) motifs. SIZ1 contains, in addition, a PHD (for plant homeodomain) typical of plant PIAS proteins. We determined phenotypes of siz1-2 knockout mutants transformed with SIZ1 alleles carrying point mutations in the predicted domains. Domain SP-RING is required for SUMO conjugation activity and nuclear localization of SIZ1. Salicylic acid (SA) accumulation and SA-dependent phenotypes of siz1-2, such as diminished plant size, heightened innate immunity, and abscisic acid inhibition of cotyledon greening, as well as SA-independent basal thermotolerance were not complemented by the altered SP-RING allele of SIZ1. The SXS domain also controlled SA accumulation and was involved in greening and expansion of cotyledons of seedlings germinated in the presence of abscisic acid. Mutations of the PHD zinc finger domain and the PINIT motif affected in vivo SUMOylation. Expression of the PHD and/or PINIT domain mutant alleles of SIZ1 in siz1-2 promoted hypocotyl elongation in response to sugar and light. The various domains of SIZ1 make unique contributions to the plant's ability to cope with its environment.
Sessions 4 4 binds.Neither the extended conformation of the donor analogue nor the induced fit it causes in the protein have been observed before in an rGT.Comparison with the previously determined binary and ternary complexes of Kre2p/Mnt1p with its GDP donor product reveals that the GDP moiety of the GDP-2F-Man is bound in a similar manner.However, its β-phosphate group is in a different position, consistent with the attached 2-fluoro-mannose moiety being buried in the pocket.A triad of charged residues, E247, R245 and D361, is involved in the formation of the pocket due to conformational changes of the R245 and D361 side chains.The carboxylate group of E247 is 3.3 Å from the reactive centre, the β-face of the C1 group of mannose, suggesting its involvement in the reaction mechanism.When the donor analogue is bound, R245 no longer interacts with E247, making E247 even more catalytically relevant.Two triad residues have been shown to be essential for catalysis by sitedirected mutagenesis, and all are structurally conserved in most rGT structures, which suggests that the proposed catalytic mechanism relying on the concerted action of charged triad residues could potentially be a common mechanism for most rGTs.
Abstract The RNA interference (RNAi) has been considered as an important genetic tool and applied to develop a new living modified (LM) crop trait which is an improvement of nutrient quality or pest management. The RNAi of DvSnf7 has been used for resistance to LM maize and the Western Corn Rootworm which is a major agricultural pest for the US Corn Belt. Most of the environmental risk assessments (ERA) of double strand RNA (dsRNA) have been performed using in vitro transcript products, and not in vivo expressed product. A large amount of dsRNA was required for the acute toxicity assay of water fleas. Therefore development of massive dsRNA purification techniques is critical. Daphnia, a freshwater microcrustacean, is a model organism for studying cellular and molecular mechanism involved in life history traits and ecotoxicology. In this study, we established the massive dsRNA purification method using Escherichia coli and implemented acute toxicity assays to Daphnia magna . As a result, the present RNase A and DNase I, dsRNA was efficiently purified without any special techniques or equipment. Even though purified dsRNA existed during the acute toxicity test, lethality or abnormal behavior were not observed in D. magna . These results indicated that GFP and DvSnf7 dsRNA were not significantly affected to D. magna due to their lack of sequence matching in its genome. The purification method of dsRNA and the acute toxicity assay of water fleas using purified dsRNA would be suitable for the toxicological studies of LMOs to aquatic non‐target organisms.
고염 스트레스에 대한 연구는 농업 생산성에 직결되기 때문에, 고염에 대한 식물의 반응 및 신호전달, 적응기작은 중요한 연구주제가 되어 왔다. 현재까지 연구된 고염 스트레스에 대한 저항성 기작 및 유전학적 요소들이 많이 밝혀졌는데도 불구하고 아직 많은 연구를 필요로 하고 있다. 그래서 본 연구에서는 모델식물로 잘 알려진 애기장대에 pSK1015 vector로 T-DNA를 삽입하여 고염 스트레스에 대해 감수성을 보이는 돌연변이체, ssm1 돌연변이체를 선별하였다. ssm1 돌연변이체는 고염 스트레스를 받게 되면 이온의 독성 스트레스와 세포내 삼투압의 불균형에서 오는 스트레스에 대해 대조군에 비해 감수성을 보였다. ssm1 돌연변이체의 genomic DNA 상의 T-DNA가 삽입된 부위를 찾기 위하여 genomic DNA mutant library screening을 수행한 결과, 기존의 알려진 syntaxin 기능 및 환경 스트레스에 관련된 F3M18/AtSYP61/OSM1 임을 알 수 있었다. Salt stress is one of major environmental factors influencing plant growth and development. To identify salt tolerance determinants in higher plants, a large-scale screen was conducted with a bialaphos marker-based T-DNA insertional collection of Arabidopsis ecotype C24 mutants. One line for salt stress-sensitive mutant (referred to as ssm1) exhibited increased sensitivity to both ionic (NaCl) and nonionic (mannitol) osmotic stress in a root growth assay. This result suggests that ssm1 mutant is involved in ion homeostasis and osmotic compensation in plant. Molecular cloning of the genomic DNA flanking T-DNA insert of ssm1 mutant was achieved by mutant genomic DNA library screening. T-DNA insertion appeared in the first exon of an open reading frame on F3M18.7, which is the same as AtSYP61. SSM1 is SYP61/OSM1 that is a member of the SNARE superfamily of proteins required for vesicular/target membrane fusions and factor related to abiotic stress.
BACKGROUND: RNA interference (RNAi) eliminates or decreases gene expression by disrupting the target mRNA or by interfering with translation. Recently, RNAi technique was applied to generate new crop traits which provide protection against pests. To establish the environmental risk assessment protocol of RNAi LMO in lab scale, we developed dsRNA expression system using E. coli and tested acute oral toxicity assay to honey.
METHOD AND RESULTS: The dsRNA expression vector, L4440, was chosen and cloned 240 bp of Snf7 and GFP gene fragment. To develop the maximum dsRNA induction condition in E. coli, we tested induction time, temperature and IPTG concentration in media. To estimate the risk assessment of dsRNA to honey bee, it has been selected and cultured with dsRNA supplement for 48 hours according to OECD guideline. As a result, the optimum condition of dsRNA induction was 37℃, 4 hours and 0.4 mM IPTG concentration and the difference between Snf7 and GFP dsRNA molecules from E. coli was not significant in survival and behavior to honey bee. Furthermore, blast search results indicated that effective match of predicted dsRNA fragments were not existed in honey bee genome.
CONCLUSION: In this study, we developed and tested the acute oral toxicity of dsRNA using E. coli expression system to honey bee.
Min-A Seol, Jung Ro Lee, Wonkyun Choi, Beom-Ho Jo, Jeong Chan Moon, Su Young Shin, Soon-Jae Eum, Il Ryong Kim, and Hae-Ryong Song. Journal of Plant Biotechnology 2015;42:196-203. https://doi.org/10.5010/JPB.2015.42.3.196
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