• Microbiology and Biotechnology Letters
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• v.19 no.1
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• pp.37-44
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• 1991

- I aimed to isolate trans-acting factors involved in the basal expression level of eukaryotic genes. One of the yeast histidine biosynthetic gene, HIS5 was taken as a model for this study. HIS5 gene has a substantial basal level in amino acid rich medium and is derepressed if starved for any single amino acid. The derepression is mediated by cis-acting DNA sequences 5'-TGACTC-3' found in 5' non-transcribed region of the gene and trans-acting factors including GCN4 as positive factor and its negative factor GCDI 7, and GCNZ as a negative factor of GCD17. I first investigated the role of these trans-acting factors in HIS5 basal expression level by using HIS5-pH05 fusion in which expression of pH05 gene encoding inorganic phosphate-repressible acid phosphatase (APase) is regulated by HIS5 promoter. Strain with gcn2 or gcn4 mutation showed 3 to 4 fold lower APase activity than wild type. The level of APase activity was similar in gcn2 and gcn4 mutants. Trans-acting factors involved in basal level were identified by isolating 14 mutants showing increased expression of HISSPH05 fusion from gcn4 background. All the mutants carry a single nuclear recessive mutation and fall into four complementation groups, designated as bell (basal expression level), be12, be23 and be14.

• Proceedings of the Zoological Society Korea Conference
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• 1995.10b
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• pp.82-82
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• 1995

Regulation of enzyme synthesis by transcriptional and translational control systems provides rather stable adaptation to change of amino acid level in the growth medium, while manipulation of enzyme activity through endproduct feedback inhibition represents rather short-term and reversible ways of adjusting metabolic fluctuation of amino acid level. Various control mechanisms interplay to regulate genes encoding enzymes for amino acid biosynthesis in the yeast, Sacchromyces cerevisiae. When amino acids are in short supply, genes under a cross-pathway regulatory mechanism Or general amino acid control (general control) increase their action, in which Gcn4p is the major positive regulator of gene expression. When cells are cultured in minimal medium, basal level expression is also regulated by supplementary control elements, where inorganic phosphate level is additionally involved. Most of amino acid biosynthetic genes are also regulated by the level of endproduct of the pathway. This pathway-specific regulatory mechanism is called specific amino acid control (specific controD, under which gene expression is reduced when endproduct is present in the medium. Derepression of a gene through general control can be usually overridden by repression through specific control, where the endproduct level of that particular pathway is high and not limiting. In this presentation, regulatory factors for basal level expression and general control of yeast amino acid biosynthesis will be discussed, m addition to pathway-specific repression patterns and interaction between CrOSS- and specific-control mechanisms. Preliminary results are also presented from the investigation of the cloned genes in the threonine biosynthetic pathway of the yeast. yeast.

• Animal cells and systems
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• v.5 no.3
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• pp.217-224
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• 2001

The present study examines the expression and regulation of gonadotropin-releasing hormone (GnRH) and its receptor (GnRH-R) mRNA levels during mouse ovarian development. A fully processed, mature GnRH mRNA together with intron-containing primary transcripts was expressed in the immature mouse ovary as determined by Northern blot analysis and reverse transcription-polymerase chain reaction (RT-PCR). The size of ovarian GnRH mRNA was similar to that of hypothalamus, but its amount was much lower than that in the hypothalamus. Quantitative RT-PCR procedure also revealed the expression of GnRH-R mRNA in the ovary, but the estimated amount was a thousand-fold lower than that in the pituitary gland. We also examined the regulation of ovarian GnRH and GnRH-R mRNA levels during the follicular development induced by pregnant mare's serum gonadotropin (PMSG) and/or human chorionic gonadotropin (hCG). Ovarian luteinizing hormone receptor (LH-R) mRNA was abruptly increased st 48 h after the PMSG administration and rapidly decreased to the basal level thereafter. Ovarian GnRH mRNA level was slightly decreased at 48 h after the PMSG administration, and then returned to the basal value. GnRH-R mRNA level began to increase at 24 h after the PMSG treatment, decreased below the uninduced basal level at 48 h, and gradually increased thereafter. HCG administration did not alter ovarian GnRH mRNA level, while it blocked the PMSG-induced increase in GnRH mRNA level. Taken together, the present study demonstrates that the expression of GnRH and GnRH-R mRNA are regulated by gonadotropin during follicular development, suggesting possible intragonadal paracrine roles of GnRH and GnRH-R in the mouse ovarian development.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.8
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• pp.3797-3800
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• 2014

Background: BMI1, TWIST1 and SNAI2/SLUG have been implicated in aggressive behavior of squamous cell carcinoma (SCC) and melanoma and BMI1 expression could identify subtypes of Merkel cell carcinoma (MCC). However, BMI1, TWIST1 and SNAI2 expression levels in basal cell carcinomas (BCCs) have not been elucidated. We hypothesized BCC could be a good model system to decipher mechanisms which inhibit processes that drive tumor metastasis. The aim of this study was to examine the mRNA expression level of BMI1, TWIST1, and SNAI2 in BCCs. Materials and Methods: Thirty-five fresh non-metastatic BCC tissue samples and seven fresh normal skin tissue samples were evaluated by real-time RT-PCR. Results: BMI1 and TWIST1 demonstrated marked down-regulation (p<0.00l, p=0.00l respectively), but SNAI2 showed no significant change (p=0.12). Conclusions: Previous literature has clearly demonstrated a positive association between BMI1 and TWIST1 expression and metastatic BCC, aggressive SCC and melanoma. Here, we demonstrated a negative association between BMI1 and TWIST1 mRNA expression level and BCC.

• Journal of Nutrition and Health
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• v.31 no.8
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• pp.1235-1243
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• 1998

Although an elevated plasma level of high density lipoprotein (HDL) is known as a protective component against the development of atherosclerosis and ensuing coronary heart diseases, the related mechanisms are still not established . It has been clearly demonstrated in the early stages of atherogenesis that adhesion of monocytes and lymphocytes to the vascular endothelium is enhanced via adhesion molecules, and that monocytes and macrophages accumulate in the subendothelial space. The present study has investigated whether isolated plasma HDL plays a role in protection against atherogenesis by inhibiting the expression of vascular cell adhesioin molecule-1(VCAM-1) on the endothelial cells. Effects of plasma native low density lipoprotein (LDL) and ac ethylated LDL(AcLDL) on VCAM-1 expression were also examined by using an immunocytochemical technique. While plasma HDL did not alter the basal expression of VCAM-1 , lipopolysaccharide(LPS) induction of this adhesion modlecule was markedly inhibited at a phyaiological concentration of HDL. In contrast, 30$\mu\textrm{g}$ protein/ml AcLDL increased sifnificantly both basal VCAM-1 expression and its LPD induction , suggesting that this modified LDL enhances leukocyte adhesiion to endothelial cells. Unlike AcLDL , plasma native LDL inhibited significantly VCAM-1 expression. This indicates that LDL did not undergo oxidative modificantion while incubated with endothelial cells. These results suggest that plasam HDL may inhibit atherogenesis by reducing the expression of adhesion molecules, which is a protective mechanism independent of tis reverse cholesterol transport function . Modified LDL is a potent iducer for adhesion molecules in vascular endothelical cells and could play a role in the pathogenesis of atherosclerosis by adhering to blood cells.

• Proceedings of the Zoological Society Korea Conference
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• 1998.10b
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• pp.113-113
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• 1998

In Saccharomyces cerevisiae UV irradiation and a variety of chemical DNA -damaging agents induce the transcription of specific genes, including several involved in DNA repair. One of the best characterized of DNA -damage inducible genes is PHRI, which encodes the apoenzyme for DNA photolyase. Basal-level and damage-induced expression of PHRI require an upstream activation sequence, UASPHRI. Here we report the identification of the UlvIE6 gene of S. cerevisiae as a regulator of UASPHRl activity. Surprisingly, the effect of deletion of UME6 is growth phase dependent. In wild-type cells PHRI is induced in late exponential phase, concomitant with the initiation of glycogen accumulation that precedes the diauxic shift. Deletion of UNIE6 abolishes this induction, decreases the steady-state concentration of photolyase molecules and PHRI mRNA, and increases the UV sensitivity of a rad2 mutant. The results suggest that UM E6 contributes to the regulated expression of a subset of damage-responsive genes in yeast. Furthermore, the upstream repression sequence, URSPHRI, is required for repression and damage-induced expression of PHRl. Here we show identification of YER169W and YDR096W as putative regulators acting through $URS_{PHRI}$. These open reading frames were designated as RPHI (YERl69W) and RPH2 (YDR096W) indicating regulator of PHRI. Simultaneous disruption of both genes showed a synergistic effect, producing a four-fold increase in basal level expression and a similar decrease m the induction ratio following treatment of methyl methanesulfonate(MMS). Mutation of the sequence ($AG_4$) bound by Rphlp rendered the promoter of PHRI insensitive to changes in RPHI or RPH2 status. The data suggest that RPHI and RPH2 act as damage-responsive negative regulators of PHRI. Surprisingly, the sequence bound by Rphlp in vitro is found to be $AG_4$ which is identical to the consensus binding site for the regulators Msn2p and Msn4p involved in stress-induced expression. Deletion of MSN2 and MSN4 has little effect on the induction$.$ ratio following DNA damage. However, all deletions led to a significant decrease in basal-level and induced expression of PHRI. These results imply that MSN2 and MSN4 are positive regulators of P HRI but are not required for DNA damage repression. [Supported by grant from NIH]om NIH]

• Oncology Letters
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• v.41 no.2
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• pp.1075-1082
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• 2019

In a previous study, we reported that α-smooth muscle actin (α-SMA), one of the mesenchymal marker proteins, is highly expressed in tamoxifen-resistant breast cancer (TamR) cells. However, the exact mechanism of α-SMA expression in TamR cells is not fully understood. Here, we investigated the effect of TP53 on α-SMA expression in breast cancer cells. The levels of α-SMA mRNA and protein expression were analyzed by real-time PCR and western blotting, respectively. In estrogen receptor-positive [ER(+)] breast cancer patients, aberrant α-SMA expression was found to be associated with a poor prognosis. The level of α-SMA expression was significantly increased in established TamR cells compared to tamoxifen-sensitive (TamS) cells. To verify the regulatory mechanism of α-SMA expression, we analyzed diverse kinase activities between TamS and TamR cells. The activity of TP53 was markedly increased in the TamR cells. When TamS cells were treated with TP53 activator, Nutlin3 (Nut3), α-SMA expression was increased in the TamS cells. In addition, α-SMA expression was significantly increased by TP53 overexpression in breast cancer cells. On the contrary, the basal level of α-SMA expression was decreased by the TP53 inhibitor, pifithrin-α (PFT-α). Taken together, we demonstrated that α-SMA expression is regulated by TP53 activity in TamR cells.

• Molecules and Cells
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• v.38 no.6
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• pp.540-547
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• 2015

Attention deficit/hyperactivity disorder (ADHD) is one of the most common neurodevelopmental disorders, affecting approximately 5% of children. However, the neural mechanisms underlying its development and treatment are yet to be elucidated. In this study, we report that an ADHD mouse model, which harbors a deletion in the Git1 locus, exhibits severe astrocytosis in the globus pallidus (GP) and thalamic reticular nucleus (TRN), which send modulatory GABAergic inputs to the thalamus. A moderate level of astrocytosis was displayed in other regions of the basal ganglia pathway, including the ventrobasal thalamus and cortex, but not in other brain regions, such as the caudate putamen, basolateral amygdala, and hippocampal CA1. This basal ganglia circuit-selective astrocytosis was detected in both in adult (2-3 months old) and juvenile (4 weeks old) $Git1^{\check{s}/\check{s}}$ mice, suggesting a developmental origin. Astrocytes play an active role in the developing synaptic circuit; therefore, we performed an immunohistochemical analysis of synaptic markers. We detected increased and decreased levels of GABA and parvalbumin (PV), respectively, in the GP. This suggests that astrocytosis may alter synaptic transmission in the basal ganglia. Intriguingly, increased GABA expression colocalized with the astrocyte marker, GFAP, indicative of an astrocytic origin. Collectively, these results suggest that defects in basal ganglia circuitry, leading to impaired inhibitory modulation of the thalamus, are neural correlates for the ADHD-associated behavioral manifestations in $Git1^{\check{s}/\check{s}}$ mice.

• The Korean Journal of Physiology
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• v.29 no.2
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• pp.259-267
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• 1995

The renin-angiotensin system plays an important role in the regulation of blood pressure and in body fluid homeostasis. There is increasing evidence for generation of endogenous angiotensin II in many organs and for its role in paracrine functions. Studies were designed to investigate whether hemorrhage produces rapid changes in the gene expression of angiotensinogen in peripheral and brain tissues. Wistar rats received saline drinking water for 7 days, were bled at a rate of $3\;ml\;kg^{-1}\;min^{-1}$ for 7 min, and then decapitated 0, 2, 4, 8, or 24 hr after hemorrhage. Hemorrhage produced a produced hypotension with tachycardia at $2{\pm}8\;hr$, but blood pressure and heart rate had not fully recovered to the basal level at 24 hr. Plasma renin concentration was significantly increased at 2, 4, and 8 hr (maximum sixfold increase at 4 hr) and had returned to the basal level at 24 hr. Renal renin content was significantly increased only at 4 hr after hemorrhage. Angiotensinogen mRNA in both the kidney and liver were stimulated at 2 to 8 hrs, but recovered to the basal level at 24 hr. On the other hand, angiotensinogen mRNA levels il the hypothalamus and brainstem were continuously increased from 2 to 24 hrs. The present study demonstrates the presence of angiotensinogen mRNA in both hepatic and extrahepatic tissues, and more importantly, their up-regulation after hemorrhage. These results suggest that the angiotensinogen-generating systems in the liver, kideny and brain are, at least in part, under independent control and play a local physiological role.

• Asian-Australasian Journal of Animal Sciences
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• v.31 no.5
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• pp.686-695
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• 2018

Objective: The objective of this study was to investigate the effects of dietary choline supplementation on hepatic lipid metabolism and gene expression in finishing pigs with intrauterine growth retardation (IUGR). Methods: Using a $2{\times}2$ factorial design, eight normal birth weight (NBW) and eight IUGR weaned pigs were fed either a basal diet (NBW pigs fed a basal diet, NC; IUGR pigs fed a basal diet, IC) or a diet supplemented with two times more choline than the basal diet (NBW pigs fed a high-choline diet, NH; IUGR pigs fed a high-choline diet, IH) until 200 d of age. Results: The results showed that the IUGR pigs had reduced body weight compared with the NBW pigs (p<0.05 from birth to d 120; p = 0.07 from d 120 to 200). Increased (p<0.05) free fatty acid (FFA) and triglyceride levels were observed in the IUGR pigs compared with the NBW pigs. Choline supplementation decreased (p<0.05) the levels of FFAs and triglycerides in the serum of the pigs. The activities of malate dehydrogenase and glucose 6-phosphate dehydrogenase were both increased (p<0.05) in the livers of the IUGR pigs. Choline supplementation decreased (p<0.05) malate dehydrogenase activity in the liver of the pigs. Gene expression of fatty acid synthase (FAS) was higher (p<0.05) in the IC group than in the other groups, and choline supplementation decreased (p<0.05) FAS and acetyl-CoA carboxylase ${\alpha}$ expression in the livers of the IUGR pigs. The expression of carnitine palmitoyl transferase 1A (CPT1A) was lower (p<0.05) in the IC group than in the other groups, and choline supplementation increased (p<0.05) the expression of CPT1A in the liver of the IUGR pigs and decreased (p<0.01) the expression of hormone-sensitive lipase in both types of pigs. The gene expression of phosphatidylethanolamine N-methyltransferase (PEMT) was higher (p<0.05) in the IC group than in the other groups, and choline supplementation significantly reduced (p<0.05) PEMT expression in the liver of the IUGR pigs. Conclusion: In conclusion, the lipid metabolism was abnormal in IUGR pigs, but the IUGR pigs consuming twice the normal level of choline had improved circulating lipid parameters, which could be related to the decreased activity of nicotinamide adenine dinucleotide phosphate-generating enzymes or the altered expressions of lipid metabolism-related genes.