• BMB Reports
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• v.42 no.12
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• pp.834-839
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• 2009

DNA methyltransferase (DNMT) 1 is the key enzyme responsible for DNA methylation, which often occurs in CpG islands located near the regulatory regions of genes and affects transcription of specific genes. In this study, we examined the possible association of DNMT1 polymorphisms with HBV clearance and the risk of hepatocellular carcinoma (HCC). Seven common polymorphic sites were selected by considering their allele frequencies, haplotype-tagging status and LDs for genotyping in larger-scale subjects (n = 1,100). Statistical analysis demonstrated that two intron polymorphisms of DNMT1, +34542G > C and +38565G > T, showed significant association with HBV clearance in a co-dominant model (OR = 1.30, $P^{corr}$ = 0.03) and co- dominant/recessive model (OR = 1.34-1.74, $P^{corr}$ = 0.01-0.03), respectively. These results suggest that two intron polymorphisms of DNMT1, +34542G > C and +38565G > T, might affect HBV clearance.

• Clinical and Experimental Reproductive Medicine
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• v.45 no.1
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• pp.17-24
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• 2018

Objective: To investigate sperm chromatin/DNA integrity, global DNA methylation, and DNMT mRNA transcription in men with oligoasthenoteratozoospermia (OAT) compared with normozoospermic men. Methods: Semen samples from 32 OAT patients who comprised the case group and 32 normozoospermic men who comprised the control group were isolated and purified using a standard gradient isolation procedure according to World Health Organization criteria. DNMT1, DNMT3A, and DNMT3B transcripts were then compared between groups using real-time quantitative reverse-transcription polymerase chain reaction. Global DNA methylation in sperm was determined by an enzyme-linked immunosorbent assay. Protamine deficiency and the proportion of apoptotic spermatozoa were evaluated using chromomycin A3 (CMA3), aniline blue (AB), and toluidine blue (TB) staining, as well as the terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay. The p-values < 0.05 were considered to indicate statistical significance. Results: Significantly higher proportions of AB+, TB+, CMA3+, and TUNEL+ spermatozoa, as well as DNMT3A and DNMT3B transcription, were found in the OAT group. Positive correlations were detected between sperm parameters, DNA/chromatin damage, and DNMT3A and DNMT3B transcripts. Global DNA methylation was significantly higher in the OAT patients and had a significant correlation with abnormal results of all sperm chromatin integrity tests, but was not associated with DNMT1, DNMT3A, or DNMT3B expression. Conclusion: Oligoasthenoteratozoospermic men showed abnormal sperm parameters, abnormal chromatin/DNA integrity, and a higher global DNA methylation rate, as well as overexpression of DNMT mRNA.

• 한국생물공학회:학술대회논문집
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• 2005.10a
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• pp.979-979
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• 2005

• Parasites, Hosts and Diseases
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• v.55 no.2
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• pp.109-114
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• 2017

Protein arginine methyltransferase (PRMT) is an important epigenetic regulator in eukaryotic cells. During encystation, an essential process for Acanthamoeba survival, the expression of a lot of genes involved in the encystation process has to be regulated in order to be induced or inhibited. However, the regulation mechanism of these genes is yet unknown. In this study, the full-length 1,059 bp cDNA sequence of Acanthamoeba castellanii PRMT1 (AcPRMT1) was cloned for the first time. The AcPRMT1 protein comprised of 352 amino acids with a SAM-dependent methyltransferase PRMT-type domain. The expression level of AcPRMT1 was highly increased during encystation of A. castellanii. The EGFP-AcPRMT1 fusion protein was distributed over the cytoplasm, but it was mainly localized in the nucleus of Acanthamoeba. Knock down of AcPRMT1 by synthetic siRNA with a complementary sequence failed to form mature cysts. These findings suggested that AcPRMT1 plays a critical role in the regulation of encystation of A. castellanii. The target gene of AcPRMT1 regulation and the detailed mechanisms need to be investigated by further studies.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.5
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• pp.2207-2212
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• 2012

Overexpression of DNA methyltransferase 1 (DNMT1) has been detected in many cancers. Tobacco exposure is known to induce genetic and epigenetic changes in the pathogenesis of malignancy. 4-(Methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) is an important carcinogen present in tobacco smoke; however the detailed molecular mechanism of how NNK induces esophageal carcinogenesis is still unclear. We found that DNMT1 was overexpressed in ESCC tissues compared with paired non-cancerous tissues, the overexpression being correlated with smoking status and low expression of $RAR{\beta}$. The latter could be upregulated by NNK treatment in Het-1A cells, and the increased DNMT1 expression level reflected promoter hypermethylation and downregulation of retinoic acid receptor ${\beta}$($RAR{\beta}$). RNA interference mediated knockdown of DNMT1 resulted in promoter demethylation and upregulation of $RAR{\beta}$ in KYSE30 and TE-1 cells. 3-(4,5-Dimethyl-thiazol-2yl)-2,5-diphenyltetrazolium bromide (MTT) and flow cytometric analysis demonstrated that NNK treatment in Het-1A cells could enhance cell proliferation and inhibit cell apoptosis in a dose-dependent manner. In conclusion, DNMT1 overexpression is correlated with smoking status and low expression of $RAR{\beta}$ in esophageal SCC patients. NNK could induce $RAR{\beta}$ promoter hypermethylation through upregulation of DNMT1 in esophageal squamous epithelial cells, finally leading to enhancement of cell proliferation and inhibition of apoptosis.

• Proceedings of the Korean Society of Developmental Biology Conference
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• 1998.07a
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• pp.50-51
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• 1998

guanidinoacetate methyltransferase (GAMT) catalyzes the last step of creatine biosynthesis in mammals. Creatine plays an important role in cellular energy metabolism in variety of tissues including brain and male reproductive tract. Congenital deficiency of the enzyme leads to a neurologic disorder in humans. We used an interspecific backcross DNA panel to map Gamt to the central region of mouse Chromosome (Chr) 10 near the locus of hesitant mutation affecting male fertility. We assigned the human GAMT gene to Chr 19 by PCR analysis of a human/rodent somatic hybrid cell line DNA panel, and further localized the human gene to Chr 19 at band p13.3 by PCR analysis of a human radiation hybrid DNA panel. Human chr 19p13.3 is homologous to the central part of mouse Chr 10 where mouse Gamt is located. Furthermore, this part of mouse Chr 10 contains mutant loci the phenotype of which is similar to the GAMT deficiency in human.

• The Journal of the Korean bone and joint tumor society
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• v.15 no.1
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• pp.13-25
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• 2009

Purpose: The DNA repair protein, $O^6$-methylguanine-DNA methyltransferase (MGMT), removes alkyl adducts from the $O^6$ position of guanine. Epigenetic inactivation of MGMT has been found in human neoplasia and considered one of the implicated factors in chemoresistance. Materials and Methods: Sixty-two patiensts with soft tissue sarcomas (STS) were analyzed for the status of MGMT protein expression by immunohistochemistry and the promoter hypermethylation of the MGMT gene using methylation-specific PCR. Result: The loss of MGMT expression was found in 20 cases (32.3%) of total 62 STS. MGMT promoter hypermethylation rate was 25.0% (11/44 cases). The loss of MGMT expression showed significant association with high AJCC stage, high FNCLCC grade, and aggressive behavior. However,when the group who received chemotherapy was analyzed (n=27), loss of MGMT expression was correlated with worse survival in multivariate analysis (p=0.024). MGMT promoter hypermethylation is associated with high FNCLCC grade. MGMT promoter hypermethylation status had a strong correlation with loss of MGMT expression (p=0.000). Conclusion: Our results suggest that MGMT promoter hypermethylation and loss of MGMT expression had a tendency to be associated with poor prognosis and that loss of MGMT protein expression is frequently occurs via MGMT promoter hypermethylation.

• Journal of Applied Biological Chemistry
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• v.44 no.3
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• pp.119-124
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• 2001

NTR1 gene of Brassica campestris L. ssp. perkinensis encodes a floral nectary-specific methyltransferase. In this study, the NTR1 cDNA was expressed in E. coli to examine the enzymatic characteristics of the protein product. The GST-NTR1 fusion protein was purified to near homogeneity, showing that the size of NTR1 was 44 kDa. The protein reacted specifically with jasmonic acid (JA), consuming methyl group from S-adenosyl-L-methionine (SAM). GC-MS analysis revealed that the compound produced was authentic methyl jasmonate (MeJA), suggesting that NTR1 is an S-adenosyl-L-methionine: jasmonic acid carboxyl methyltransferase. Km values of NTR1 for JA and SAM were 38.0 and $6.4{\mu}M$, respectively. Optimal activity of the NTR1 was observed at $20^{\circ}C$, pH 7.5, in the presence of 100-150 mM KCl. Thus, kinetic properties, thermal characteristics, optimal pH, and ion-dependency of the NTR1 activity were almost identical to those of Arabidopsis JA methyltransferase JMT, indicating that these two proteins are orthologues of each other.

• Proceedings of the Zoological Society Korea Conference
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• 1997.10b
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• pp.225.1-225
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• 1997

No Abstract, See Full Text

• Tuberculosis and Respiratory Diseases
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• v.70 no.3
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• pp.206-217
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• 2011

Background: Transcription factor FOXP3 characterizes the thymically derived regulatory T cells. FOXP3 is expressed by cancer cell itself and FOXP3 expression was induced by TGF-${\beta}$ treatment in pancreatic cancer cell line. However, the expression of FOXP3 expression is not well known in patients with lung cancer. This study was conducted to investigate the expression of FOXP3 in patients with lung cancer and to investigate the regulation of FOXP3 expression by the treatment of TGF-${\beta}$ and DNA methyltransferase inhibitor in lung cancer cell lines. Methods: FOXP3 expression in the tissue of patients with resected non-small cell lung cancer (NSCLC) was evaluated by immunohistochemistry. The regulation of FOXP3 expression was investigated by Western blot and RT-PCR after lung cancer cell lines were stimulated with TGF-${\beta}1$ and TGF-${\beta}2$. The regulation of FOXP3 expression was also investigated by RT-PCR and flow cytometry after lung cancer cell lines were treated with DNA methyltransferase inhibitor (5-AZA-dC). Results: FOXP3 expression was confirmed in 27% of patients with NSCLC. In NCI-H460 cell line, TGF-${\beta}2$ decreased FOXP3 mRNA and protein expressions. In A549 cell line, both TGF-${\beta}1$ and TGF-${\beta}2$ decreased FOXP3 mRNA and protein expressions. 5-AZA-dC increased FOXP3 mRNA expression in NCI-H460 and A549 cell lines. Moreover, 5-AZA-dC increased intracellular FOXP3 protein expression in A549 cell lines. Conclusion: It was shown that FOXP3 is expressed by cancer cell itself in patients with NSCLC. Treatment of TGF-${\beta}2$ and DNA methyltransferase inhibitor seems to be associated with the regulation of FOXP3 expression in lung cancer cell lines.