• The Korean Journal of Physiology and Pharmacology
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• v.23 no.3
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• pp.171-179
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• 2019

Pituitary tumors are usually benign but can occasionally exhibit hormonal and proliferative behaviors. Dysregulation of the G1/S restriction point largely contributes to the over-proliferation of pituitary tumor cells. F-box protein S-phase kinase-interacting protein-2 (SKP2) reportedly targets and inhibits the expression of $p27^{Kip1}$, a well-known negative regulator of G1 cell cycle progression. In this study, SKP2 expression was found to be upregulated while $p27^{Kip1}$ expression was determined to be downregulated in rat and human pituitary tumor cells. Furthermore, SKP2 knockdown induced upregulation of $p27^{Kip1}$ and cell growth inhibition in rat and human pituitary tumor cells, while SKP2overexpression elicited opposite effects on $p27^{Kip1}$ expression and cell growth. The expression of microRNA-186 (miR-186) was reported to be reduced in pituitary tumors. Online tools predicted SKP2 to be a direct downstream target of miR-186, which was further confirmed by luciferase reporter gene assays. Moreover, miR-186 could modulate the cell proliferation and $p27^{Kip1}$-mediated cell cycle alternation of rat and human pituitary tumor cells through SKP2. As further confirmation of these findings, miR-186 and $p27^{Kip1}$ expression were downregulated, while SKP2 expression was upregulated in human pituitary tumor tissue samples; thus, SKP2 expression negatively correlated with miR-186 and $p27^{Kip1}$ expression. In contrast, miR-186 expression positively associated with $p27^{Kip1}$ expression. Taken together, we discovered a novel mechanism by which miR-186/SKP2 axis modulates pituitary tumor cell proliferation through $p27^{Kip1}$-mediated cell cycle alternation.

• Animal Bioscience
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• v.36 no.4
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• pp.555-569
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• 2023

Objective: The objective of this study was to investigate the effects of N⁶-Methyladenosine modification-circRNA-zinc finger protein 638 (m⁶A-circRNA-ZNF638) on the induced activation of secondary hair follicle (SHF) stem cells with its potential mechanisms in cashmere goats. Methods: The m⁶A modification of ZNF638 was analyzed using methylation immunoprecipitation with real-time quantitative polymerase chain reaction technique in SHF stem cells. The effects of circRNA-ZNF638 on the induced activation of SHF stem cells in m⁶A dependence were evaluated through the overexpression of circRNA-ZNF638/its m⁶A-deficient mutants in circRNA-ZNF638 knockdown SHF stem cells. The competitive binding of miR-361-5p to circRNA-ZNF638/Wnt5a 3'- untranslated region was analyzed through Dual-luciferase reporter assay. Results: The m⁶A-circRNA-ZNF638 had significantly higher transcription at anagen SHF bulge of cashmere goats compared with that at telogen, as well as it positively regulated the induced activation of SHF-stem cells in cashmere goats. Mechanismly, m⁶A-circRNA-ZNF638 sponged miR-361-5p to heighten the transcriptional expression of Wnt5a gene in SHF-stem cells. We further demonstrated that the internal m⁶A modification within circRNA-ZNF638 is required for mediating the miR-361-5p/Wnt5a pathway to regulate the induced activation of SHF stem cells through an introducing of m⁶A-deficient mutant of circRNA-ZNF638. Conclusion: The circRNA-ZNF638 contributes the proper induced activation of SHF-stem cells in cashmere goats in m⁶A-dependent manner through miR-361-5p/Wnt5a axis.

• Korean Journal of Animal Reproduction
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• v.25 no.3
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• pp.237-242
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• 2001

We recently demonstrated that both linear- and supercoil-form B1/B2 SINE (short interspersed elements) sequences could increase an integration frequency of a reporter gene in preimplatation mouse embryos. In those reports, when either a control or SINE-flanked DNA was separately applied to microinjection, the proportions of $\beta$-gal positives were 16% and 63%, respectively, in linear-form DNA, and 6% and 25%, respectively, in circular-form DNA. Here, we examined the contribution of a circular-form DNA moiety to integration frequency by using a mixed-farm (linear and circular-form) DNA in microinjection. When examined in the blastocyst stage, the proportion of $\beta$-gal-positive embryos was 17.3% and 46.6% in control and SINE-flanked DNA, respectively. These results suggest that there is little contribution of circular-form DNA moiety to the resultant integration frequency, and that the majority of the integration events are mediated through a linear conformation of vector DNA. In addition, some clues on integration process could be obtained from the analysis of microinjection results.

• Molecules and Cells
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• v.45 no.3
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• pp.122-133
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• 2022

The aim of this study was to investigating whether lncRNA H19 promotes myocardial fibrosis by suppressing the miR-29a-3p/miR-29b-3p-VEGFA/TGF-β axis. Patients with atrial fibrillation (AF) and healthy volunteers were included in the study, and their biochemical parameters were collected. In addition, pcDNA3.1-H19, si-H19, and miR-29a/b-3p mimic/inhibitor were transfected into cardiac fibroblasts (CFs), and proliferation of CFs was detected by MTT assay. Expression of H19 and miR-29a/b-3p were detected using real-time quantitative polymerase chain reaction, and expression of α-smooth muscle actin (α-SMA), collagen I, collagen II, matrix metalloproteinase-2 (MMP-2), and elastin were measured by western blot analysis. The dual luciferase reporter gene assay was carried out to detect the sponging relationship between H19 and miR-29a/b-3p in CFs. Compared with healthy volunteers, the level of plasma H19 was significantly elevated in patients with AF, while miR-29a-3p and miR-29b-3p were markedly depressed (P < 0.05). Serum expression of lncRNA H19 was negatively correlated with the expression of miR-29a-3p and miR-29b-3p among patients with AF (r_s = -0.337, r_s = -0.236). Moreover, up-regulation of H19 expression and down-regulation of miR-29a/b-3p expression facilitated proliferation and synthesis of extracellular matrix (ECM)-related proteins. SB431542 and si-VEGFA are able to reverse the promotion of miR-29a/b-3p on proliferation of CFs and ECM-related protein synthesis. The findings of the present study suggest that H19 promoted CF proliferation and collagen synthesis by suppressing the miR-29a-3p/miR-29b-3p-VEGFA/TGF-β axis, and provide support for a potential new direction for the treatment of AF.

• Journal of Microbiology and Biotechnology
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• v.33 no.4
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• pp.552-558
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• 2023

Levulinic acid (LA) is a valuable chemical used in fuel additives, fragrances, and polymers. In this study, we proposed possible biosynthetic pathways for LA production from lignin and poly(ethylene terephthalate). We also created a genetically encoded biosensor responsive to LA, which can be used for screening and evolving the LA biosynthesis pathway genes, by employing an LvaR transcriptional regulator of Pseudomonas putida KT2440 to express a fluorescent reporter gene. The LvaR regulator senses LA as a cognate ligand. The LA biosensor was first examined in an Escherichia coli strain and was found to be non-functional. When the host of the LA biosensor was switched from E. coli to P. putida KT2440, the LA biosensor showed a linear correlation between fluorescence intensity and LA concentration in the range of 0.156-10 mM LA. In addition, we determined that 0.156 mM LA was the limit of LA detection in P. putida KT2440 harboring an LA-responsive biosensor. The maximal fluorescence increase was 12.3-fold in the presence of 10 mM LA compared to that in the absence of LA. The individual cell responses to LA concentrations reflected the population-averaged responses, which enabled high-throughput screening of enzymes and metabolic pathways involved in LA biosynthesis and sustainable production of LA in engineered microbes.

• Microbiology and Biotechnology Letters
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• v.41 no.1
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• pp.17-25
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• 2013

The thermotolerant methylotrophic yeast Hansenula polymorpha is an attractive model organism for various fundamental studies, such as the genetic control of enzymes involved in methanol metabolism, peroxisome biogenesis, nitrate assimilation, and resistance to heavy metals and oxidative stresses. In addition, H. polymorpha has been highlighted as a promising recombinant protein expression host, especially due to the availability of strong and tightly regulatable promoters. In this study, we investigated the possibility of employing human serum albumin (HSA) as the fusion tag for the secretory expression of heterologous proteins in H. polymorpha. A set of four expression cassettes, which contained the methanol oxidase (MOX) promoter, translational HSA fusion tag, and the terminator of MOX, were constructed. The expression cassettes were also designed to contain sequences for accessory elements including His8-tag, $2{\times}(Gly_4Ser_1)$ linkers, tobacco etch virus protease recognition sites (Tev), multi-cloning sites, and strep-tags. To determine the effects of the size of the HSA fusion tag on the secretory expression of the target protein, each cassette contained the HSA gene fragment truncated at a specific position based on its domain structure. By using the Green fluorescence protein gene as the reporter, the properties of each expression cassette were compared in various conditions. Our results suggest that the translational HSA fusion tag is an efficient tool for the secretory expression of recombinant proteins in H. polymorpha.

• Journal of Life Science
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• v.16 no.4
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• pp.632-639
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• 2006

Here we examined the expression patterns and regulation of seven photosynthesis (PS) genes (puf, puc, puhA, bchC, bchE, bchF, and bchI) in the anoxygenic photosynthetic bacterium, Rhodobacter sphaeroides, based on lacZ reporter gene assay. Expression of the tested PS genes, except puhA and bchI, were strongly induced in R. sphaeroides grown under anaerobic conditions relative to that under aerobic conditions. The puhA and bchI genes appear to form the operons together with bchFNBHLM-RSP0290 and crtA, respectively. Expression of the puf, puc, and bchCXYZ operons in R. sphaeroides grown photosynthetically was proportional to the incident light intensity, whereas that of bchFNBHLM(RSP0290-puhA) was inversely related to light intensity. Expression of bchEJG was lowest under medium-light photosynthetic conditions $(10\;W/m^2)$ and highest under high light conditions $(100\;W/m^2)$. The regulation of PS genes by the three major regulatory systems involved in oxygen- and light-sensing in R. sphaeroides is as following: puf and bchC are regulated by both the PpsR repressor and the PrrBA two-component system. The puc operon is under control of PpsR, FnrL, and PrrBA system. Expression of bchE is controlled by FnrL and PrrBA two-component system, whereas bchF is regulated exclusively by PpsR. It was demonstrated that the PpsR repressor is responsible for high-light repression of bchF and that FnrL might be involved in perceiving the cellular redox state in addition to sensing $O_2$ itself.

• Journal of Plant Biotechnology
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• v.35 no.3
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• pp.169-176
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• 2008

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.

• Journal of the Korean Society of Food Science and Nutrition
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• v.40 no.6
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• pp.767-774
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• 2011

Defatted green tea seed was extracted with 100% ethanol for 4 hr and then fractionated with petroleum ether, ethyl acetate and butanol. The ethanol and butanol extracts showed greater increases in antiproliferation potential against liver cancer cells than petroleum ether, ethyl acetate, $H_2O$, and hot water extracts did. Thus, this study was carried out to investigate the anti-proliferative actions of defatted green tea seed ethanol extract (DGTSE) in HepG2 cancer cells. The DGTSE contained catechins including EGC ($1039.1{\pm}15.2\;g/g$), tannic acid ($683.5{\pm}17.61\;{\mu}g/g$), EC ($62.4{\pm}5.00\;{\mu}g/g$), ECG ($24.4{\pm}7.81\;{\mu}g/g$), EGCG ($20.9{\pm}0.96\;{\mu}g/g$) and gallic acid ($2.4{\pm}0.68\;{\mu}g/g$), but caffeic acid was not detected when analyzed by HPLC. The anti-proliferation effect of DGTSE toward HepG2 cells was 83.13% when treated at $10\;{\mu}g$/mL, of DGTSE, offering an $IC_{50}$ of $6.58\;{\mu}g$/mL. DGTSE decreased CYP1A1 and CYP1A2 protein expressions in a dose-dependent manner. Quinone reductase and antioxidant response element (ARE)-luciferase activities were increased about 2.6 and 1.94-fold at a concentration of $20\;{\mu}g$/mL compared to a control group, respectively. Enhancement of phase II enzyme activity by DGTSE was shown to be mediated via interaction with ARE sequences in genes encoding the phase enzymes. DGTSE significantly (p<0.05) suppressed prostaglandin $E_2$ level, tumor necrosis factor-${\alpha}$ (TNF-${\alpha}$) protein expressions, and NF${\kappa}$B translocation, but did not affected nitric oxide production. From the above results, it is concluded that DGTSE may ameliorate tumor and inflammatory reactions through the elevation of phase II enzyme activities and suppression of NF${\kappa}$B translocation and TNF-${\alpha}$ protein expressions, which support the cancer cell anti-proliferative effects of DGTSE in HepG2 cells.

• Molecules and Cells
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• v.37 no.2
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• pp.178-186
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• 2014

Differential transcription of the clusterin (CLU) gene yields two CLU isoforms, a nuclear form (nCLU) and a secretory form (sCLU), which play crucial roles in prostate tumorigenesis. Pro-apoptotic nCLU and anti-apoptotic sCLU have opposite effects and are differentially expressed in normal and cancer cells; however, their regulatory mechanisms at the transcriptional level are not yet known. Here, we examined the transcriptional regulation of nCLU in response to hypoxia. We identified three putative hypoxia response elements (HREs) in the human CLU promoter between positions -806 and +51 bp. Using a luciferase reporter, electrophoretic gel mobility shift, and chromatin immunoprecipitation assays, we further showed that hypoxia-inducible factor-$1{\alpha}$ (HIF-$1{\alpha}$) bound directly to these sites and activated transcription. Exposure to the hypoxia-mimetic compound $CoCl_2$, incubation under 1% $O_2$ conditions, or overexpression of HIF-$1{\alpha}$ enhanced nCLU expression and induced apoptosis in human prostate cancer PC3M cells. However, LNCaP prostate cancer cells were resistant to hypoxia-induced cell death. Methylation-specific PCR analysis revealed that the CLU promoter in PC3M cells was not methylated; in contrast, the CLU promoter in LNCap cells was methylated. Co-treatment of LNCaP cells with $CoCl_2$ and a demethylating agent promoted apoptotic cell death through the induction of nCLU. We conclude that nCLU expression is regulated by direct binding of HIF-$1{\alpha}$ to HRE sites and is epigenetically controlled by methylation of its promoter region.