• Molecules and Cells
• /
• v.28 no.5
• /
• pp.463-472
• /
• 2009

Although the possible cellular roles of several ubiquitin-specific proteases (UBPs) were identified in Arabidopsis, almost nothing is known about UBP homologs in rice, a monocot model plant. In this report, we searched the rice genome database (http://signal.salk.edu/cgi-bin/RiceGE) and identified 21 putative UBP family members (OsUBPs) in the rice genome. These OsUBP genes each contain a ubiquitin carboxyl-terminal hydrolase (UCH) domain with highly conserved Cys and His boxes and were subdivided into 9 groups based on their sequence identities and domain structures. RT-PCR analysis indicated that rice OsUBP genes are expressed at varying degrees in different rice tissues. We isolated a full-length cDNA clone for OsUBP6, which possesses not only a UCH domain, but also an N-terminal ubiquitin motif. Bacterially expressed OsUBP6 was capable of dismantling K48-linked tetra-ubiquitin chains in vitro. Quantitative real-time RT-PCR indicated that OsUBP6 is constitutively expressed in different tissues of rice plants. An in vivo targeting experiment showed that OsUBP6 is predominantly localized to the nucleus in onion epidermal cells. We also examined how knock-out of OsUBP6 affects developmental growth of rice plants. Although homozygous T3 osubp6 T-DNA insertion mutant seedlings displayed slower growth relative to wild type seedlings, mature mutant plants appeared to be normal. These results raise the possibility that loss of OsUBP6 is functionally compensated for by an as-yet unknown OsUBP homolog during later stages of development in rice plants.

• Journal of Plant Biotechnology
• /
• v.38 no.2
• /
• pp.125-129
• /
• 2011

Environmental risk assessment (RA) is essential prior to the environmental release of GM crops. RA, however, costs at least 7 to 15 million US dollars and requires several years to complete field tests. Therefore, it is strongly suggested that developers of GM crops must consider all criteria for RA at the beginning stage of the development if it aims for commercialization. Previous review papers have pointed out that the "death valley" for the commercialization of GM crops is the screening stage of early GM events since many candidates are given up due to insufficient data on the molecular characterization of a GM event such as inserted gene's copy number, position of inserted site of a chromosome, flanking sequence of recombinant T-DNA, rearrangement of chromosome, and knock out of endogenous gene of host plant. Recently, Rural Development Administration (RDA) in South Korea has launched a Grand National Project named as "Next Generation of BioGreen 21 Project" from 2011 to 2020 and research funding for the development of global GM crops has been allocated to accelerate the commercialization of GM crops. In this regard, I strongly suggest that researchers involved in the development of GM crops for commercialization must conduct RA by themselves at the screening stage of pre-GM event based on the data for molecular characterization.

• BMB Reports
• /
• v.36 no.1
• /
• pp.49-59
• /
• 2003

Platelet-derived growth factor (PDGF) is a critical regulator of mesenchymal cell migration and proliferation. The vital functions of PDGFs for angiogenesis, as well as development of kidney, brain, cardiovascular system and pulmonary alveoli during embryogenesis, have been well demonstrated by gene knock-out approaches. Clinical studies reveal that aberrant expression of PDGF and its receptor is often associated with a variety of disorders including atherosclerosis, fibroproliferative diseases of lungs, kidneys and joints, and neoplasia. PDGF contributes to cancer development and progression by both autocrine and paracrine signaling mechanisms. In this review article, important features of the PDGF isoforms and their cell surface receptor subunits are discussed, with regards to signal transduction, PDGF-isoform specific cellular response, and involvement in angiogenesis, and tumorstromal interactions.

• YAKHAK HOEJI
• /
• v.51 no.3
• /
• pp.214-218
• /
• 2007

In the previous reports, we developed the CO5 by introducing genes for the first and second urea cycle enzymes, carbamoyl phosphate synthetase I (CPS I) and ornithine transcarbamoylase (OTC) into the IBE cell lines producing erythropoietin (EPO). The CO5 have been found out to have 15-20% higher cell growth rate and produce 2-times more EPO than the parental cell line, IBE. To investigate the role of CPS I in CO5 cell line for the cell growth and amount of EPO, we knock-downed CPS I gene expression via siRNA treatment. Expression level of EPO in cell lysate of CO5 was 3-5 fold higher than that of IBE. After siRNA treatment, the cell growth of CO5 was decreased 8-21% and the EPO productivity in the cell Iysate was significantly decreased. However, these changes of the cell growth and EPO productivity were not observed in IBE. These results indicate that CPS I gene expression is important for the increased cell growth and EPO productivity of CO5 cell line.

• Proceedings of the Korean Society of Crop Science Conference
• /
• 2017.06a
• /
• pp.134-134
• /
• 2017

Recently, host-induced gene silencing (HIGS) system has been successfully applied into development of resistant crops against insects, fungal and viral pathogens. To test HIGS-mediated resistance in rice against rice blast fungus, Magnaporthe oryzae, we first tested possibility of movement of small non-coding RNA from rice cells to rice blast fungus. The rice blast fungus expressing GFP transgene were inoculated to transgenic rice plants ectopically expressing dsRNAi construct targeting fungal GFP gene. Expression of dsRNAi construct for GFP gene in transgenic plants significantly suppressed GFP expression in infected fungal cells indicating that small RNAs generated in plant cells can move into infected fungal cells and efficiently suppress the expression of fungal GFP gene. Consistent with these results, expression of dsRNAi constructs against 3 fungal pathogenic genes of M. oryzae in transgenic rice specifically and efficiently suppressed not only the expression of fungal pathogenic genes, but also fungal infection. The conidia of M. oryzae applied on leaf sheath of transgenic rice expressing dsRNAs against 3 fungal pathogenic genes showed abnormal development of primary hyphae and malfunction of appressorium, which is consistent with the phenotypes of corresponding fungal knock-out mutants. Taken these results together, here, we suggest a novel strategy for development of antifungal crops by means of HIGS system.

• Reproductive and Developmental Biology
• /
• v.35 no.3
• /
• pp.197-201
• /
• 2011

This study was conducted to investigate the effects of donor cell treatments on the production of transgenic cloned piglets. Ear fibroblast cell obtained from NIH MHC Inbred minipig was used as control. The GalT knock-out/CD45 knock-in (GalT/CD46) transgenic cell lines were established and used as donor cells. The reconstructed GalT/CD46 embryos were surgically transferred into oviduct of naturally cycling surrogate sows (Landrace ${\times}$ Yorkshire) on the second day of standing estrus. Unlike control (1.2 kV/cm, 75.4%), the fusion rate of the GalT/CDl6 donor cells was significantly higher in 1.5 kV/cm, (84.5%) than that of 1.25 kV/cm, (20.2%) (p<0.01). When the number of the transferred embryos were more than 129, the pregnancy and delivery rates were increased to 13/20 (65%) and 5/20 (25%) compared to less then 100 group [1/6 (16.7%) and 0/6 (0%)], respectively. To analyze the effect of donor cell culture condition on pregnancy and delivery rates, the GalT/CD46 donor cells were cultured with DMEM or serum reduced medium. In serum reduced medium group, the pregnancy and delivery rates were improved to 8/12 (66.7%) and 5/12 (41.7%) compared to DMEM group [3/7 (42.9%) and 0/7 (0%)], respectively. In conclusion, it can be postulated that an appropriate fusion condition and culture system is essential factors to increase the efficiency of the production of transgenic cloned piglets.

• Proceedings of the Korean Society of Applied Pharmacology
• /
• 2001.04a
• /
• pp.103-112
• /
• 2001

Bone homeostasis is maintained by a balance between activities of osteoblasts(bone forming cells) and osteoclasts (bone resorbing cells). The activities of these cells are closely regulated by multiple factors including hormones and cytokines. The cessation of estrogen at menopause disrupts the balanced regulation and is the main cause of osteoporosis in postmenopausal women. Recent molecular biological studies led to a discovery of tumor necrosis factor(TNF) and TNF receptor families genes that play critical roles in the regulation of osteoclast formation and function. RANKL (receptor activator of nuclear factor kappa B ligand; also called ODF, TRANCE, and OPGL) expressed on cells supporting osteoclast is essential for osteoclast differentiation, activation, and survival. RANK, the counter-receptor for RANKL, is expressed on progenitor and mature osteoclasts. The interaction between RANKL and RANK is requlated by a soluble decoy receptor OPG (osteoprotegerin). Gene knock out studies of these molecules showed profound effects on bone. These results prompted development of new strategies for treatment of bone diseases. Inhibition of osteoclast activity by blocking the RANKL-RANK interaction using OPG is being attempted. Research on the signaling pathways of RANK is also actively carried out. Screening natural products that inhibit the RANKL-RANK interaction or the activity of obteoclasts would be another effective means to a new drug target for bone resorbing diseases.

• Korean Journal of Microbiology
• /
• v.46 no.4
• /
• pp.401-404
• /
• 2010

Tho1 is a RNA-binding protein that assembles co-transcriptionally onto the nascent mRNA and is thought to be involved in mRNP biogenesis and mature mRNA export to cytoplasm in budding yeast. In fission yeast Schizosaccharomyces pombe, a homologue of THO1 (spTho1) was identified based on sequence alignment. A deletion mutant in a diploid strain was constructed by replacing one of spTho1-coding region with an ura4+ gene using one-step gene disruption method. Tetrad analysis showed that the spTho1 was not essential for growth. The spTho1 mutant did not show any defects of bulk mRNA export. However, over-expression of spTho1 from strong nmt1 promoter caused the growth defects and accumulation of poly(A)$^+$ RNA in the nucleus. These results suggest that spTho1 is involved in mRNA export from the nucleus to cytoplasm though it is not essential.

• Reproductive and Developmental Biology
• /
• v.35 no.4
• /
• pp.511-518
• /
• 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 Plant Biotechnology
• /
• v.35 no.3
• /
• pp.177-183
• /
• 2008

Ac/Ds mutant lines of this study were transgenic rice plants, each of which harbored the maize transposable element Ds together with a GUS coding sequence under the control of a promoterless(Ds-GUS). We selected the mutants that were GUS expressed lines, because the GUS positive lines will be useful for identifying gene function in rice. One of these mutants was identified knock-out at Oszinc626(NP_001049991) gene, encoding a RING-H2 zinc-finger protein, by Ds insertion. In this mutant, while primary root development is normal, secondary root development from lateral root was very poor and seed development was incomplete compare with normal plant. RING zinc-finger proteins play important roles in the regulation of development in a variety of organisms. In the plant kingdom, a few genes encoding RING zinc-finger proteins have been documented with visible effects on plant growth and development. The consensus of the RING-H2(C3-H2-C3 type) domain for this group of protein is $Cys-X_2-Cys-X_{28}-Cys-X-His-X_2-His-X_2-Cys-X_{14}-Cys-X_2-Cys$. Oszinc626 encodes a predicted protein product of 445 amino acids residues with a molecular mass of 49 kDa, with a RING-zinc-finger motif located at the extreme end of the C-terminus. RT-PCR analysis indicated that the expression of Oszinc626 gene was induced by IAA, cold, dehydration, high-salinity and abscisic acid, but not by 2,4-D, and the transcription of Oszinc626 gene accumulated primarily in rice immature seeds, root meristem and shoots. The gene accumulation patterns were corresponded with GUS expression.