• 한국미생물·생명공학회지
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• 제24권6호
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• pp.693-698
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• 1996

Optimal cultural conditions were investigated for the maximal productivity of nucleoside oxidase and peroxidase from Flavobacterium meningosepticum. Sucrose and Polypepton were the best as a carbon source and a nitrogen source. Fe$^{2+}$, Fe$^{3+}$ and Cu$^{2+}$ increased the activities of the two enzymes and were essential in medium containing peptone as a nitrogen source. Nucleoside derivatives such as 2'-deoxyguanosine, 2'-deoxyadenosine, N$^{6}$ -methyladenosine and 1-methyladenosine were effective for the production of the two enzymes. Especially, the addition of N$^{6}$ -methyladenosine and 1-methyladenosine decreased cell growth, but increased the two enzyme activities. High level of oxygen also was an essential factor for formation and/or induction of these enzymes. From the summary of this study about optimal medium and environmental conditions, nucleoside oxidase was biosynthesized in proportion to peroxidase. These results suggested that the role of peroxidase should be degradation of H$_{2}$O$_{2}$ generated by nucleoside oxidase in the cell of Flavobacterium meningosepticum.

• Journal of Microbiology and Biotechnology
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• 제34권2호
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• pp.233-239
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• 2024

N6-methyladenosine (m6A) RNA methylation has recently emerged as a significant co-transcriptional modification involved in regulating various RNA functions. It plays a vital function in numerous biological processes. Enzymes referred to as m6A methyltransferases, such as the methyltransferase-like (METTL) 3-METTL14-Wilms tumor 1 (WT1)-associated protein (WTAP) complex, are responsible for adding m6A modifications, while m6A demethylases, including fat mass and obesity-associated protein (FTO) and alkB homolog 5 (ALKBH5), can remove m6A methylation. The functions of m6A-methylated RNA are regulated through the recognition and interaction of m6A reader proteins. Recent research has shown that m6A methylation takes place at multiple sites within hepatitis B virus (HBV) RNAs, and the location of these modifications can differentially impact the HBV infection. The addition of m6A modifications to HBV RNA can influence its stability and translation, thereby affecting viral replication and pathogenesis. Furthermore, HBV infection can also alter the m6A modification pattern of host RNA, indicating the virus's ability to manipulate host cellular processes, including m6A modification. This manipulation aids in establishing chronic infection, promoting liver disease, and contributing to pathogenesis. A comprehensive understanding of the functional roles of m6A modification during HBV infection is crucial for developing innovative approaches to combat HBV-mediated liver disease. In this review, we explore the functions of m6A modification in HBV replication and its impact on the development of liver disease.

• International Journal of Stem Cells
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• 제16권2호
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• pp.135-144
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• 2023

Background and Objectives: Melanocyte (MC), derived from neural crest stem cell (NCSC), are involved in the production of melanin. The mechanism by which NCSC differentiates to MC remains unclear. N6-methyladenosine (m6A) modification was applied to discuss the potential mechanism. Methods and Results: NCSCs were isolated from hair follicles of rats, and were obtained for differentiation. Cell viability, tyrosinase secretion and activity, and transcription factors were combined to evaluated the MC differentiation. RT-qPCR was applied to determine mRNA levels, and western blot were used for protein expression detection. Total m6A level was measured using methylated RNA immunoprecipitation (MeRIP) assay, and RNA immunoprecipitation was used to access the protein binding relationship. In current work, NCSCs were successfully differentiated into MCs. Fat mass and obesity associated gene (FTO) was aberrant downregulated in MCs, and elevated FTO suppressed the differentiation progress of NCSCs into MCs. Furthermore, microphthalmia-associated transcription factor (Mitf), a key gene involved in MC synthesis, was enriched by FTO in a m6A modification manner and degraded by FTO. Meanwhile, the suppression functions of FTO in the differentiation of NCSCs into MCs were reversed by elevated Mitf. Conclusions: In short, FTO suppressed the differentiating ability of hair follicle-derived NCSCs into MCs by m6A modifying Mitf.

• Molecules and Cells
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• 제46권10호
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• pp.589-591
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• 2023

• Animal Bioscience
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• 제36권4호
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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.

• Molecules and Cells
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• 제45권7호
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• pp.435-443
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• 2022

In response to environmental changes, signaling pathways rewire gene expression programs through transcription factors. Epigenetic modification of the transcribed RNA can be another layer of gene expression regulation. N⁶-adenosine methylation (m⁶A) is one of the most common modifications on mRNA. It is a reversible chemical mark catalyzed by the enzymes that deposit and remove methyl groups. m⁶A recruits effector proteins that determine the fate of mRNAs through changes in splicing, cellular localization, stability, and translation efficiency. Emerging evidence shows that key signal transduction pathways including TGFβ (transforming growth factor-β), ERK (extracellular signal-regulated kinase), and mTORC1 (mechanistic target of rapamycin complex 1) regulate downstream gene expression through m⁶A processing. Conversely, m⁶A can modulate the activity of signal transduction networks via m⁶A modification of signaling pathway genes or by acting as a ligand for receptors. In this review, we discuss the current understanding of the crosstalk between m⁶A and signaling pathways and its implication for biological systems.

• 미생물학회지
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• 제55권2호
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• pp.103-111
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• 2019

DNA 메틸화는 유전체의 무결성의 유지 및 유전자 발현 조절과 같은 박테리아의 다양한 과정에 관여한다. Alphaproteobacteria 종에서 보존된 DNA 메틸 전이 효소인 CcrM은 S-아데노실 메티오닌을 공동 기질로 사용하여 $N^6$-아데닌 또는 $N^4$-시토신의 메틸 전이 효소 활성을 갖는다. Celeribacter marinus IMCC 12053는 해양 환경에서 분리된 알파프로테오박테리아로서 GpC 시토신의 외향고리 아민의 메틸기를 대체하여 $N^4$-메틸 시토신을 생산한다. 단일 분자 실시간 서열 분석법(SMRT)을 사용하여, C. marinus IMCC12053의 메틸화 패턴을 Gibbs Motif Sampler 프로그램을 사용하여 확인하였다. 5'-GANTC-3'의 $N^6$-메틸 아데노신과 5'-GpC-3'의 $N^4$-메틸 시토신을 확인하였다. 발현된 DNA 메틸전이 효소는 계통 발생 분석법을 사용하여 선택하여 pQE30 벡터에 클로닝 후 $dam^-/dcm^-$ 대장균을 사용하여 클로닝된 DNA 메틸라아제의 메틸화 활성을 확인하였다. 메틸화 효소를 코딩하는 게놈 DNA 및 플라스미드를 추출하고 메틸화에 민감한 제한 효소로 절단하여 메틸화 활성을 확인하였다. 염색체와 메틸라아제를 코드하는 플라스미드를 메틸화시켰을 때에 제한 효소 사이트가 보호되는 것으로 관찰되었다. 본 연구에서는 분자 생물학 및 후성유전학을 위한 새로운 유형의 GpC 메틸화 효소의 잠재적 활용을 위한 외향고리 DNA 메틸라제의 특성을 확인하였다.

• Journal of Ginseng Research
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• 제45권6호
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• pp.734-743
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• 2021

Background: The underlying mechanisms of the potential tumor-suppressive effects of ginsenoside Rh2 are complex. N6-methyladenosine (m6A) RNA methylation is usually dysregulated in cancer. This study explored the regulatory effect of ginsenoside Rh2 on m6A RNA methylation in cancer. Methods: m6A RNA quantification and gene-specific m6A RIP-qPCR assays were applied to assess total and gene-specific m6A RNA levels. Co-immunoprecipitation, fractionation western blotting, and immunofluorescence staining were performed to detect protein interactions and distribution. QRT-PCR, dual-luciferase, and ChIP-qPCR assays were conducted to check the transcriptional regulation. Results: Ginsenoside Rh2 reduces m6A RNA methylation and KIF26B expression in a dose-dependent manner in some cancers. KIF26B interacts with ZC3H13 and CBLL1 in the cytoplasm of cancer cells and enhances their nuclear distribution. KIF26B inhibition reduces m6A RNA methylation level in cancer cells. SRF bound to the KIF26B promoter and activated its transcription. SRF mRNA m6A abundance significantly decreased upon KIF26B silencing. SRF knockdown suppressed cancer cell proliferation and growth both in vitro and in vivo, the effect of which was partly rescued by KIF26B overexpression. Conclusion: ginsenoside Rh2 reduces m6A RNA methylation via downregulating KIF26B expression in some cancer cells. KIF26B elevates m6A RNA methylation via enhancing ZC3H13/CBLL1 nuclear localization. KIF26B-SRF forms a positive feedback loop facilitating tumor growth.

• 한국동물생명공학회지
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• 제37권2호
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• pp.121-129
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• 2022

Heterogeneous nuclear ribonucleoprotein A2/B1 (hnRNPA2/B1) is an N6-methyladenosine (m⁶A) RNA modification regulator and a key determinant of prem-RNA processing, mRNA metabolism and transportation in cells. Currently, m⁶A reader proteins such as hnRNPA2/B1 and YTHDF2 has functional roles in mice embryo. However, the role of hnRNPA2/B1 in porcine embryogenic development are unclear. Here, we investigated the developmental competence and mRNA expression levels in porcine parthenogenetic embryos after hnRNPA2/B1 knock-down. HhnRNPA2/B1 was localized in the nucleus during subsequent embryonic development since zygote stage. After hnRNPA2/B1 knock-down using double stranded RNA injection, blastocyst formation rate decreased than that in the control group. Moreover, hnRNPA2/B1 knock-down embryos show developmental delay after compaction. In blastocyste stage, total cell number was decreased. Interestingly, gene expression patterns revealed that transcription of Pou5f1, Sox2, TRFP2C, Cdx2 and PARD6B decreased without changing the junction protein, ZO1, OCLN, and CDH1. Thus, hnRNPA2/B1 is necessary for porcine early embryo development by regulating gene expression through epigenetic RNA modification.

• BMB Reports
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• 제55권12호
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• pp.633-638
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• 2022

Liver regeneration is a well-known systemic homeostatic phenomenon. The N⁶-methyladenosine (m⁶A) modification pathway has been associated with liver regeneration and hepatocellular carcinoma. m⁶A methyltransferases, such as methyltransferase 3 (METTL3) and methyltransferase 14 (METTL14), are involved in the hepatocyte-specific-regenerative pathway. To illustrate the role of METTL14, secreted from non-parenchymal liver cells, in the initiation phase of liver regeneration, we performed 70% partial hepatectomy (PH) in Mettl14 heterozygous (HET) and wild-type (WT) mice. Next, we analyzed the ratio of liver weight to body weight and the expression of mitogenic stimulators derived from non-parenchymal liver cells. Furthermore, we evaluated the expression of cell cycle-related genes and the hepatocyte proliferation rate via MKI67-immunostaining. During regeneration after PH, the weight ratio was lower in Mettl14 HET mice compared to WT mice. The expressions of hepatocyte growth factor (HGF) and tumor necrosis factor (TNF)-α, mitogens derived from non-parenchymal liver cells that stimulate the cell cycle, as well as the expressions of cyclin B1 and D1, which regulate the cell cycle, and the number of MKI67-positive cells, which indicate proliferative hepatocyte in the late G1-M phase, were significantly reduced in Mettl14 HET mice 72 h after PH. Our findings demonstrate that global Mettl14 mutation may interrupt the homeostasis of liver regeneration after an acute injury like PH by restraining certain mitogens, such as HGF and TNF-α, derived from sinusoidal endothelial cells, stellate cells, and Kupffer cells. These results provide new insights into the role of METTL14 in the clinical treatment strategies of liver disease.