Reportedly, DNMT2/TRDMT1 mainly methylates tRNAs at C38 and prevents them from the cleavage under stress. It also plays an essential role in the survival and physiological homeostasis of organisms. Nevertheless, DNMT2/TRDMT1 exhibits much weaker tRNA methylation activity in vitro than other tRNA methyltransferases, TrmD and Trm5. Here, we explored the restricted tRNA methylation mechanism by DNMT2/TRDMT1. In the current study, the optimized buffer C at 37 °C was the best condition for DNMT2/TRDMT1 activation. Of note, Dithiothreitol (DTT) was an indispensable component for this enzyme catalysis. Moreover, reductants took similar effects on the conformation change and oligomeric formation of DNMT2/TRDMT1. Ultimately, LC-MS/MS result revealed that C292-C292 and C292-C287 were predominant intermolecular disulfide bonds in recombinant DNMT2/TRDMT1. Notably, DNMT2/TRDMT1 existed primarily as dimers via intermolecular disulfide bonds C79-C24, C292-C292, and C222-C24 in HEK293T cells. GSSG stress enhanced tRNA methylation level in the early stage of stress, whereas the DNMT2/TRDMT1 activity might be unfavorable along with this enzyme accumulation in the nucleus. Excitingly, GSH stress downregulated the DNMT2/TRDMT1 expression and promoted tRNA methylation in cells, probably through breaking intermolecular disulfide bonds in this enzyme. Thus, our findings demonstrated restricted tRNA methylation by disulfide bonds in DNMT2/TRDMT1, and will provide important implications for redox stress related-diseases.
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http://dx.doi.org/10.1016/j.ijbiomac.2023.126310 | DOI Listing |
Structure
January 2025
Department of Hepatobiliary Surgery, Innovative Institute of Tumor Immunity and Medicine (ITIM), Anhui Province Key Laboratory of Tumor Immune Microenvironment and Immunotherapy, The First Affiliated Hospital of Anhui Medical University, Hefei 230022, China. Electronic address:
NSUN6 preferentially catalyzes the methylation of cytosine nucleotides in mRNA substrates, which enhances transcription. Dysregulation of NSUN6 catalysis drives the oncogenesis of certain cancers. In this study, we determined the crystal structure of human NSUN6 in complex with its S-adenosyl-L-methionine analog and a bound NECT-2 3'-UTR RNA substrate at 2.
View Article and Find Full Text PDFInt J Mol Sci
January 2025
Department of Biochemistry and Biotechnology, Poznań University of Life Sciences, 60-632 Poznań, Poland.
Atherosclerosis is accompanied by inflammation that underlies cardiovascular disease (CVD) and its vascular manifestations, including acute stroke, myocardial infarction, and peripheral artery disease, the leading causes of morbidity/mortality worldwide. The monolayer of endothelial cells formed on the luminal surface of arteries and veins regulates vascular tone and permeability, which supports vascular homeostasis. Endothelial dysfunction, the first step in the development of atherosclerosis, is caused by mechanical and biochemical factors that disrupt vascular homeostasis and induce inflammation.
View Article and Find Full Text PDFJ Nutr
January 2025
Department of Animal Sciences, North Carolina State University, Raleigh, NC 27695, USA. Electronic address:
Background: Supplementing choline and docosahexaenoic acid (DHA) to pregnant gilts modified fetal pig hepatic global DNA methylation induced by gestational malnutrition, suggesting that gene expression and regulation and its associated metabolic pathways are affected in the liver of offspring during growth and development.
Objective: To investigate the effect of maternal supplementation of choline, DHA and their interaction on hepatic mRNA expression, miRNA regulation and metabolic pathways in the fetal pigs born to malnourished mothers.
Methods: The abundance of mRNA and miRNA was profiled in fetal liver from sows with undernutrition supplemented with choline and DHA in a 2 × 2 factorial design.
Int J Mol Sci
January 2025
Pathogenesis and Control of Pathogenic Microorganisms Research Team, School of Life and Health Sciences, Hainan Province Key Laboratory of One Health, Collaborative Innovation Center of One Health, Hainan University, Haikou 570228, China.
The trans-translation system, mediated by transfer-messenger RNA (tmRNA, encoded by the gene) and its partner protein SmpB, helps to release ribosomes stalled on defective mRNA and targets incomplete protein products for hydrolysis. Knocking out the and genes in various pathogens leads to different phenotypic changes, indicating that they have both cooperative and independent functionalities. This study aimed to clarify the functional relationships between tmRNA and SmpB in a pathogen that poses threats in aquaculture and human health.
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