• Reproductive and Developmental Biology
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• v.33 no.2
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• pp.93-98
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• 2009

In this study, bovine Dnmt1 cDNA was sequenced and detected Dnmt1 mRNA level in bovine tissues by northern blot, methylation pattern of genome by southern blot, specific localization of Dnmt1 in mouse and bovine preimplantation embryos by immunocytostaining and Dnmt1 protein level in ovary and testis by western blot. Bovine Dnmt1 cDNA sequence showed more homology with that of human than mouse and rat. The RNA level of Dnmt1 was 10 times higher expression in placenta than other tissues. This indicates that placenta was hypermethylated compared to others organs. The genomic DNA could not be cut by a specific restriction enzyme (HpaII) in placenta, lung and liver of bovine. It suggests that Dnmt1 in some somatic cells was already methylated. Dnmt1, which has the antibody epitope 1316~1616, was distributed in nucleus and cytoplasm including the stage of pronuclear stage and maturation of oocyte and gradually weaken to blastocyst stage compare to negative. In addition, Dnmt1 was strongly expressed in tetraploid embryo and cloned 8-cell than IVF 8-cell. An aberrant pattern of DNA methylation in cloned embryo may be abnormal development of fetus, embryonic lethality and placenta dysfunction. The somatic specific band (190kDa) was appeared in ovary and testis, but oocyte specific band (175kDa) was not. Further investigations are necessary to understand the complex links between the methyltransferases and the transcriptional activity of genes in the cloned bovine tissues.

• Journal of Genetic Medicine
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• v.14 no.2
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• pp.71-74
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• 2017

Mutations in the DNA methyltransferase 1 gene (DNMT1) were reported to cause two phenotypes: OMIM 604121 and OMIM 614116. The first phenotype includes autosomal dominant cerebellar ataxia, deafness, and narcolepsy, which were reported to be caused by mutations in exon 21. The second phenotype includes hereditary sensory and autonomic neuropathy type 1E, which was suggested to be caused by mutations in exon 20 and 21. In this article, we report a novel heterozygous missense variant c.898A>C, p.(Lys300Gln) in exon 12 of DNMT1 in a young woman who presented with pure cerebellar ataxia. This report indicates that a mutation in exon 12 may lead to pure cerebellar ataxia. Another possibility is that the patient is currently in an early stage of the disease, and as the disease progresses, she will have more manifestations. To confirm or exclude this possibility, a subsequent follow-up study reporting the disease progression in this patient may be needed. Further reports of cases with the same mutation are needed to confirm the phenotype of this mutation.

• Proceedings of the Korean Society of Plant Pathology Conference
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• 2003.10a
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• pp.80.1-80
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• 2003

Several plant and microbial genes that could confer disease resistance in transgenic rice plants are being cloned and characterized. We are currently constructing transgenic rice lines that overexpress the gene products, such as a galactinol synthase, a defensin, and a bacterial ACC deaminase. Subtractive hybridization of a rice cDNA library constructed from the Xanthomonas oryzae-infected ice leaves resulted in isolation of many inducible cDNA clones including a elongation factor EF2, a oryzain alpha, a catalase, a aldehyde dehydrogenase, a S-adenosylmethionine synthetase, a caffeic acid O-methyltransferase, a glyceraldehyde-3-phosphate dehydrogenase, a light-regulated protein, nKY transcription factors, and a nucleotide diphosphate kinase. Some genes among those may be useful genetic sources for construction of disease resistant transgenic rice. Full lengths of the rice OsFIERG and a rice oryzain genomic clones were cloned, and serial deletion fragments of the promoter regions of these genes were fused with GUS reporter gene in pCAMBIA1201, respectively. Promoter activities of these constructs will be examined upon various stresses and Pathogen infections to obtain the pathogen specific inducible-promoter. This work was supported by a grant from BioGreen 21 Program, Rural Development Administration, Republic of Korea.

• Asian-Australasian Journal of Animal Sciences
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• v.18 no.11
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• pp.1519-1523
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• 2005

By screening a subtracted cDNA library constructed with mRNA obtained from the longissimus dorsi muscles of F1 hybrids Landrace${\times}$Yorkshire and their Yorkshire female parents, we isolated two partial sequences coding for the H3-K4-specific methyltransferase (KIAA1717) and skeletal muscle myosin regulatory light chain (HUMMLC2B) genes. In the present work we investigated two SNPs, one (C1354T) at the 3' untranslated region (UTR) of KIAA1717 and one (A345G) at the SINE (PRE-1) element of HUMMLC2B, in a resource population derived from crossing Chinese Meishan and Large White pig. The selected pigs were genotyped by means of a PCR-RFLP protocol. Significant associations were observed for the KIAA1717 C1354T polymorphic site with thorax-waist backfat thickness (p<0.05), buttock backfat thickness (p<0.05), average backfat thickness (p<0.05), loin eye height (p<0.05), loin eye area (p<0.05), carcass length to 1$^{st}$ spondyle (p<0.01) and carcass length to 1st rib (p<0.01). HUMMLC2B A345G were significantly associated with loin eye width (p<0.05), loin eye area (p<0.05). Further studies are needed to confirm these preliminary results.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.1
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• pp.33-38
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• 2014

Background: Meningiomas are the second most common primary intracranial tumors after gliomas. Epigenetic biomarkers such as DNA methylation, which is found in many tumors and is thus important in tumorigenesis can help diagnose meningiomas and predict response to adjuvant chemotherapy. We investigated aberrant O6-methyl guanine methyltransferase (MGMT) methylation in meningiomas. Materials and Methods: Sixty-one patients were classified according to the WHO grading, and MGMT promoter methylation status was examined via the methylation-Specific PCR(MSP) method. Results: MGMT promoter methylation was found in 22.2% of grade I, 35% of grade I with atypical features, 36% of grade II, and 42.9% of grade III tumors. Conclusions: There was an increase, albeit not statistically significant, in MGMT methylation with a rise in the tumor grade. Higher methylation levels were also observed in the male gender.

• Journal of Korean Neurosurgical Society
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• v.46 no.4
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• pp.385-388
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• 2009

Objective : We analyzed the methylation status of the O6-methylguanine-DNA methyltransferase (MGMT) gene promoter in World Health Organization (WHO) grade III gliomas in association with other molecular markers to evaluate their prevalence. Methods : The samples of a total of 36 newly WHO grade III glioma patients including 19 anaplastic oligodendrogliomas (AO), 7 anaplastic oligoastrocytomas (AOA), and 10 anaplastic astrocytomas (AA) were analyzed. The methylation status of the MGMT gene promoter was confirmed by methylation-specific polymerase chain reaction. The 1p/19q chromosomal deletion status and EGFR amplification were assessed by Fluorescence In-Situ Hybridization. MGMT, EGFR, EGFRvlll, and p53 expression were analyzed by immunohistochemical staining. Results : The MGMT gene promoter was methylated in 32 (88.9%) and unmethylated in 4 (11.2%) Among them, all of the AO and AOA had methylated MGMT gene promoter without exception. Significant associations between MGMT gene promoter hypermethylation and 1p/19q deletion was observed (p=0.003). Other molecular markers failed to show significant associations between MGMT gene promoter statuses. Conclusion : There was extensive epigenetic silencing of MGMT gene in high grade gliomas with oligodendroglial component. Together with frequent 1p/19q co-deletion in oligodendroglial tumors, this may add plausible explanations supporting the relative favorable prognosis in oligodendroglial tumors compared with pure astrocytic tumors.

• Reproductive and Developmental Biology
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• v.35 no.3
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• pp.281-285
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• 2011

In the present study, we identified differentially methylated region (DMR) upstream of Dnmt1o and Dnmt1s gene in early porcine embryos. Porcine Dnmt1o had at least one DMR which was located between -530 bp to -30 bp upstream from transcription start site of the Dnmt1o gene. DNA methylation analyses of Dnmt1o revealed the DMR to be hypomethylated in oocytes, whereas it was highly methylated in sperm. Moreover, the DMR upstream of Dnmt1o was gradually hypermethylated from oocytes to two cells and dramatically changed in the methylation pattern from four cells to BL stages in an in vivo. In an IVF, the methylation status in the DMR upstream of Dnmt1o was hypermethylated from one cell to eight cells, but demethylated at the Morula and BL stages, indicating that the DNA methylation pattern in the Dnmt1o upstream ultimately changed from stage to stage before the implantation. Next, to elucidate whether DNA methylation status of Dnmt1s upstream is stage-by-stage changed in during porcine early development, we analyzed the dynamics of the DNA methylation status of the Dnmt1s locus in germ cell, or one cell to BL cells. The Dnmt1s upstream was highly methylated in one and eight cells, while less methylated in two, four, morula, and BL cells. Taken together, our data demonstrated that DNA methylation and demethylation events in upstream of Dnmt1o/Dnmt1s during early porcine embryos dramatically occurred, and this change may contribute to the maintenance of genomewide DNA methylation in early embryonic development.

• Journal of Animal Science and Technology
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• v.53 no.3
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• pp.269-274
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• 2011

DNA methyltransferases (DNMTs) are closely associated with the epigenetic change and the gene silencing through the regulation of methylation status in animal genome. But, the role of DNMTs in transgene silencing has remained unclear. So, we examined whether the knockdown of DNMT influences the reactivation of transgene expression in the transgenic quails. In this study, we investigated the expression of DNMT3a, and DNMT3b in blastoderm, quail embryonic fibroblasts (QEFs) and limited embryonic tissues such as gonad, kidney, heart and liver of E6 transgenic quails (TQ2) by RT-PCR. We further analyzed the expression of DNMT3a at different stages of whole embryos during early embryonic development by qRT-PCR. DNMT3a expression was detected in all test samples; however, it showed the highest expression in E6 whole embryo. Embryonic fibroblasts collected from TQ2 quails were treated with two DNMT3a-targeted siRNAs (siDNMT3a-51 and siDNMT3a-88) for RNA interference assay, and changes in expression were then analyzed by qRT-PCR. The siDNMT3a-51 and siDNMT3a-88 reduced 53.34% and 64.64% of DNMT3a expression in TQ2 QEFs, respectively. Subsequently the treatment of each siRNA reactivated enhanced green fluorescent protein (EGFP) expression in TQ2 (224% and 114%). Our results might provide a clue for understanding the DNA methylation mechanism responsible for transgenic animal production and stable transgene expression.

• Reproductive and Developmental Biology
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• v.31 no.4
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• pp.241-248
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• 2007

Epigenetic modification dependent DNA methyltransferases (DNMTs) play an important role in tissue- and stage-specific gene regulation and normal mammalian development. In this study, we show that DNMTs are expressed at different levels during hematopoietic stem cell (HSC) differentiation to proerythrocytes. DNMT1, DNMT3A, and DNMT3B were highly expressed at day 7 after differentiation. We used specific siRNA as a tool to probe the relationship between the expression of DNMTs and erythropoietic differentiation. When introduced siRNA of DMNT1 and DMNT3b in human $CD34^+$ cells, these more differentiated into erythrocytes. This was confirmed by glycophorin A (GPA) positive cell analysis and globin gene expression. $GPA^+$ cells increased up to $20{\sim}30%$, and ${\gamma}$- and ${\epsilon}$-globin genes increased in siRNA transfected cells. Therefore, our data suggest that suppression of DNA methylation can affect positively differentiation of HSC and may contribute to expression of erythrocyte lineage genes including GPA and globins.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.22
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• pp.9955-9960
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• 2014

Background: Promoter hypermethylation is a common event in human cancer. O6-methylguanine-DNA methyltransferase (MGMT) is a gene involved in DNA repair, which is methylated in a variety of cancers. We aimed to explore the methylation status of MGMT gene among the North Eastern population where esophageal cancer incidence and exposure to carcinogens like nitrosamines is high. Materials and Methods: A total of 100 newly diagnosed esophageal cancer cases along with equal number of age, sex and ethnicity matched controls were included in this study. Methylation specific PCR was used to determine the MGMT methylation status in serum samples. Results: Aberrant promoter methylation of the MGMT gene was detected in 70% of esophageal cancer cases. Hypermethylation of MGMT gene was found to be influenced by environmental factors like betel quid and tobacco which contain potent carcinogens like nitrosamines. Tobacco chewing and tobacco smoking habit synergistically with MGMT methylation elevated the risk for esophageal cancer development [adjusted OR=5.02, 95% CI=1.35-18.74; p=0.010 for tobacco chewing and Adjusted OR=3.00, 95% CI=1.22-7.36; p=0.014 for tobacco smoking]. Conclusions: Results suggest that the DNA hypermethylation of MGMT is an important mechanism for MGMT gene silencing resulting in esophageal cancer development and is influenced by the environmental factors. Thus MGMT hypermethylation can be used as a biomarker for esophageal cancer in high incidence region of North East India.