• Proceedings of the Botanical Society of Korea Conference
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• 1987.07a
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• pp.241-260
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• 1987

The regulatory mechanisms of gene expression in higher plant were not ascertained in detail because the genome size is very large and complex. However, the above-mentioned study is remarkably progressed in parallel with development of DNA recombinant technology and plant vector system. Some research results connected with the mechanisms could be summarized as follows. 1. Many plant genes including chloroplast genes are cloned. 2. The structures of some regulatory regions of gene expression are determined, and it is confirmed that new regulatory units are made by transposable elements. 3. Plant gene expression is regulated not only at transcriptional level but also at translational level. 4. The factors that regulate plant gene expression could be divided as two categorys. One is endogenous elements including the structural change of chromatin during development stage and tissue differentiation. The other is environmental stimulations such as air, water, heat, salts and light. However, some sufficient research-aid fund is essential in order to study the regulatory mechanisms of gene expression more systematically.

• Journal of the Korean Magnetic Resonance Society
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• v.12 no.1
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• pp.40-50
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• 2008

Ghrelin is a unique peptide hormone that releases growth factor and it stimulates appetite. It comes from pre pro-ghrelin by the post translational modification process and its innate functions are known as food up-take and the growth hormone regulation. Therefore, the structural information of ghrelin precursor is of importance in understanding it function. From our results, we found that the solution structure of ghrelin is mostly random coil conformation at neutral pH value and the structural population changes with pH environments. Data from circular dichroism in different TFE concentrations revealed that the secondary structure changes from random coil to a-helix and the isodichroic point is observed at 202nm, implying that two equilibrium states exist between random coil and helical structure.

• Journal of Cancer Prevention
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• v.22 no.4
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• pp.203-210
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• 2017

After transcription, RNAs are always associated with RNA binding proteins (RBPs) to perform biological activities. RBPs can interact with target RNAs in sequence- and structure-dependent manner through their unique RNA binding domains. In development and progression of carcinogenesis, RBPs are aberrantly dysregulated in many human cancers with various mechanisms, such as genetic alteration, epigenetic change, noncoding RNA-mediated regulation, and post-translational modifications. Upon deregulation in cancers, RBPs influence every step in the development and progression of cancer, including sustained cell proliferation, evasion of apoptosis, avoiding immune surveillance, inducing angiogenesis, and activating metastasis. To develop therapeutic strategies targeting RBPs, RNA interference-based oligonucleotides or small molecule inhibitors have been screened based on reduced RBP-RNA interaction and changed level of target RNAs. Identification of binding RNAs with high-throughput techniques and integral analysis of multiple datasets will help us develop new therapeutic drugs or prognostic biomarkers for human cancers.

• BMB Reports
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• v.55 no.11
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• pp.535-540
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• 2022

Ribosomes, acting as the cellular factories for protein production, are essential for all living organisms. Ribosomes are composed of both proteins and RNAs and are established through the coordination of several steps, including transcription, maturation of ribosomal RNA (rRNA), and assembly of ribosomal proteins. In particular, diverse factors required for ribosome biogenesis, such as transcription factors, small nucleolar RNA (snoRNA)-associated proteins, and assembly factors, are tightly regulated by various post-translational modifications. Among these modifications, small ubiquitin-related modifier (SUMO) targets lots of proteins required for gene expression of ribosomal proteins, rRNA, and snoRNAs, rRNA processing, and ribosome assembly. The tight control of SUMOylation affects functions and locations of substrates. This review summarizes current studies and recent progress of SUMOylation-mediated regulation of ribosome biogenesis.

• BMB Reports
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• v.54 no.11
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• pp.541-544
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• 2021

Protein glycosylation is a common post-translational modification found in all living organisms. This modification in bacterial pathogens plays a pivotal role in their infectious processes including pathogenicity, immune evasion, and host-pathogen interactions. Importantly, many key proteins of host immune systems are also glycosylated and bacterial pathogens can notably modulate glycosylation of these host proteins to facilitate pathogenesis through the induction of abnormal host protein activity and abundance. In recent years, interest in studying the regulation of host protein glycosylation caused by bacterial pathogens is increasing to fully understand bacterial pathogenesis. In this review, we focus on how bacterial pathogens regulate remodeling of host glycoproteins during infections to promote the pathogenesis.

• International Journal of Oral Biology
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• v.31 no.3
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• pp.93-98
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• 2006

Biosynthetic processing of fibrillar procollagens is essential for producing mature collagen monomers that polymerize into fibrils by a self-assembly process. The metalloproteinase ADAMTS-2 is the major enzyme that processes the N-propeptide of type I procollagen in the skin and also of type II and type III procollagens. Mutations in the ADAMTS-2 gene cause dermatospraxis in animals and Ehlers-Danlos syndrome VIIC in humans, both of which are characterized by the accumulation of type I pN-collagen and the formation of abnormal collagen fibrils in the skin. Despite its importance in procollagen processing, little is known about the regulation of ADAMTS-2 expression. Here, we demonstrate that ADAMTS-2 can be regulated by 1,25-dihydroxyvitamin D3, an inducer of type I procollagen synthesis. This steroid hormone induced ADAMTS-2 mRNA ${\sim}3-fold$ in MG-63 human osteosarcoma cells and MC3T3-E1 murine osteoblastic cells. This induction was dose- and time-dependent in MG-63 cells. In contrast, secreted ADAMTS-2 protein was increased only 1.4-fold with 1,25-dihydroxyvitamin D3. Finally, 1,25-dihydroxyvitamin D3 in the presence of ascorbate increased levels of secreted ADAMTS-2 1.9-fold over ascorbate treatment alone, which did not appreciably change ADAMTS-2 expression. These data indicate that the regulation of ADAMTS-2 is coupled with the synthesis of type I procollagen through 1,25-dihydroxyvitamin D3 signaling and may involve translational or posttranslational control.

• The Korean Journal of Physiology and Pharmacology
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• v.22 no.6
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• pp.679-688
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• 2018

Autism spectrum disorders (ASDs) are neurodevelopmental disorders that share behavioral features, the results of numerous studies have suggested that the underlying causes of ASDs are multifactorial. Behavioral and/or neurobiological analyses of ASDs have been performed extensively using a valid model of prenatal exposure to valproic acid (VPA). Abnormal synapse formation resulting from altered neurite outgrowth in neural progenitor cells (NPCs) during embryonic brain development has been observed in both the VPA model and ASD subjects. Although several mechanisms have been suggested, the actual mechanism underlying enhanced neurite outgrowth remains unclear. In this study, we found that VPA enhanced the expression of brain-derived neurotrophic factor (BDNF), particularly mature BDNF (mBDNF), through dual mechanisms. VPA increased the mRNA and protein expression of BDNF by suppressing the nuclear expression of methyl-CpG-binding protein 2 (MeCP2), which is a transcriptional repressor of BDNF. In addition, VPA promoted the expression and activity of the tissue plasminogen activator (tPA), which induces BDNF maturation through proteolytic cleavage. Trichostatin A and sodium butyrate also enhanced tPA activity, but tPA activity was not induced by valpromide, which is a VPA analog that does not induce histone acetylation, indicating that histone acetylation activity was required for tPA regulation. VPA-mediated regulation of BDNF, MeCP2, and tPA was not observed in astrocytes or neurons. Therefore, these results suggested that VPA-induced mBDNF upregulation was associated with the dysregulation of MeCP2 and tPA in developing cortical NPCs.

• Journal of Pharmacopuncture
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• v.15 no.3
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• pp.19-30
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• 2012

Objectives: Many efforts have shown multi-oncologic roles of galectin-3 for cell proliferation, angiogenesis, and apoptosis. However, the mechanisms by which galectin-3 is involved in cell proliferation are not yet fully understood, especially in human colon cancer cells. Methods: To cluster genes showing positively or negatively correlated expression with galectin-3, we employed human colon cancer cell lines, SNU-61, SNU-81, SNU-769B, SNU-C4 and SNU-C5 in high-throughput gene expression profiling. Gene and protein expression levels were determined by using real-time quantitative polymerase chain reaction (PCR) and western blot analysis, respectively. The proliferation rate of human colon cancer cells was measured by using a 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay. Results: Expression of ${\gamma}$-aminobutyric acid B receptor 1 (GABABR1) showed a positive correlation with galectin-3 at both the transcriptional and the translational levels. Down-regulation of galectin-3 decreased not only GABABR1 expression but also the proliferation rate of human colon cancer cells. However, Korean herbal extract, HangAmDan-B (HAD-B), decreased expression of GABABR1 without any expressional change of galectin-3, and offset ${\gamma}$-aminobutyric acid (GABA)-enhanced human colon cancer cell proliferation. Conclusions: Our present study confirmed that GABABR1 expression was regulated by galectin-3. HAD-B induced galectin-3-independent down-regulation of GABABR1, which resulted in a decreased proliferation of human colon cancer cells. The therapeutic effect of HAD-B for the treatment of human colon cancer needs to be further validated.

• BMB Reports
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• v.49 no.5
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• pp.245-246
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• 2016

The level and activity of critical regulatory proteins in cells are tightly controlled by several tiers of post-translational modifications. HIF-1α is maintained at low levels under normoxia conditions by the collaboration between PHD proteins and the VHL-containing E3 ubiquitin ligase complex. We recently identified a new physiologically relevant mechanism that regulates HIF-1α stability in the nucleus in response to cellular oxygen levels. This mechanism is based on the collaboration between the SET7/9 methyltransferase and the LSD1 demethylase. SET7/9 adds a methyl group to HIF-1α, which triggers degradation of the protein by the ubiquitin-proteasome system, whereas LSD1 removes the methyl group, leading to stabilization of HIF-1α under hypoxia conditions. In cells from knock-in mice with a mutation preventing HIF-1α methylation (Hif1α^KA/KA), HIF-1α levels were increased in both normoxic and hypoxic conditions. Hif1α^KA/KA knock-in mice displayed increased hematological parameters, such as red blood cell count and hemoglobin concentration. They also displayed pathological phenotypes; retinal and tumor-associated angiogenesis as well as tumor growth were increased in Hif1α^KA/KA knock-in mice. Certain human cancer cells exhibit mutations that cause defects in HIF-1α methylation. In summary, this newly identified methylation-based regulation of HIF-1α stability constitutes another layer of regulation that is independent of previously identified mechanisms.

• Toxicological Research
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• v.14 no.2
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• pp.123-127
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• 1998

BRCA1 is a tumor suppresser gene in familial cases of breast cancer. It has been controversial whether the subcellular localization of BRCA1 is located in nuclei or cytoplasm in normal human breast cells. We found that a p220 protein was expressed in Type II Normal human breast epithelial cells (NHBEC) but not in Type I NHBEC in Western blot analysis using the 17F8 (3A2) antibody. Immunostaining using the same antibody revealed positive staining in nuclei, cytoplasm and perinuclei of Type II cells and negative staining in Type I NHBEC. The p220 protein, however, was expressed in SV40 immortalized Type I NHBEC and tumorigenic cells derived from them after x-ray and neu oncogene treatment. The subcelluar localization was mostly cytoplasmic and punctate in the nuclei. The breast carcinoma cell lines, MCF-7 and T47D, also expressed the p220 protein. Using RT-PCR, we observed the expression of BRCA1 mRNA in both Type I and Type II NHBEC. This result indicated that there might be mechanisms involved in post-translational or translational regulation of BRCA1 gene. It is speculated that the absence of BRCA1 protein expression in Type I NHBEC might playa role in their susceptibility to neoplastic transformation.