Effects on N-methyl-N-nitrosourea (MNU) mediated methylation of the N7 position of guanine were compared in defined sequences of DNA containing cytosine or 5-methylcytosine (5mC) using a Maxam-Gilbert sequencing technique. Cytosine methylation in 5'-CpG-3' pairs within a subcloned fragment of the 5' region of the human HPRT gene was generated with SssI methylase and S-adenosylmethionine. Cytosine methylation was demonstrated by both the inhibition of DNA restriction by methylation sensitive endonucleases and the lack of cleavage at 5-methylcytosines by hydrazine. MNU-dependent methylation of the N7 position of guanine was inhibited up to 18% when 5mC was a 5' neighboring base to guanine and was inhibited up to 36% in an alternating CpG region in which both 5' and 3' neighboring bases of guanine were enzymatically altered to 5mC. It can be concluded that 5-methylcytosine has discernible effects on MNU methylation of the N7 position of specific guanine bases in DNA.
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http://dx.doi.org/10.1093/carcin/14.2.323 | DOI Listing |
New Phytol
January 2025
Leibniz Institute of Plant Genetics and Crop Plant Research Gatersleben, Corrensstrasse 3, 06466, Seeland, Germany.
The epigenetic state of chromatin, gene activity and chromosomal positions are interrelated in plants. In Arabidopsis thaliana, chromosome arms are DNA-hypomethylated and enriched with the euchromatin-specific histone mark H3K4me3, while pericentromeric regions are DNA-hypermethylated and enriched with the heterochromatin-specific mark H3K9me2. We aimed to investigate how the chromosomal location affects epigenetic stability and gene expression by chromosome engineering.
View Article and Find Full Text PDFNAR Cancer
March 2025
Ribosome, Translation and Cancer Team, LaEx DEVweCAN, Institut Convergence Plascan, LYriCAN+, Centre de Recherche en Cancérologie de Lyon, INSERM U1052, CNRS UMR 5286, Centre Léon Bérard, Université de Lyon, Université Claude Bernard Lyon 1, 69008 Lyon, France.
The epithelial-mesenchymal transition (EMT) is a dynamic transdifferentiation of epithelial cells into mesenchymal cells. EMT programs exhibit great diversity, based primarily on the distinct impact of molecular activities of the EMT transcription factors. Using a panel of cancer cell lines and a series of 71 triple-negative primary breast tumors, we report that the EMT transcription factor ZEB1 modulates site-specific chemical modifications of ribosomal RNA (rRNA).
View Article and Find Full Text PDFFEBS J
January 2025
Department of Biotechnology, The University of Tokyo, Japan.
Acetyl xylan esterase plays a crucial role in the degradation of xylan, the major plant hemicellulose, by liberating acetic acid from the backbone polysaccharides. Acetyl xylan esterase B from Aspergillus oryzae, designated AoAxeB, was biochemically and structurally investigated. The AoAxeB-encoding gene with a native signal peptide was successfully expressed in Pichia pastoris as an active extracellular protein.
View Article and Find Full Text PDFACS Omega
January 2025
School of Bio-Chemical Engineering and Technology, Sirindhorn International Institute of Technology, Thammasat University, 99 Phahonyothin Road, Khlong Nueng, Khlong Luang, Pathum Thani 12120, Thailand.
The integration of molecular docking and AM1 calculations has elucidated the complexation behavior of butylone enantiomers with methylated β-cyclodextrin derivatives. Our study reveals that butylone can adopt two distinct conformations within the β-cyclodextrin cavity, with one conformation being preferentially stabilized due to its favorable binding energy. This conformation preference is influenced by the methylation at the O2, O3, and O6 positions of β-cyclodextrin, which significantly affects complex stability and solvation properties.
View Article and Find Full Text PDFPharmaceuticals (Basel)
January 2025
Department of Microbiology, Virology and Immunology, I. Horbachevsky Ternopil State Medical University, 46001 Ternopil, Ukraine.
Background: In the era of resistance, the design and search for new "small" molecules with a narrow spectrum of activity that target a protein or enzyme specific to a certain bacterium with high selectivity and minimal side effects remains an urgent problem of medicinal chemistry. In this regard, we developed and successfully implemented a strategy for the search for new hybrid molecules, namely, the not broadly known [2-(3-R-1-[1,2,4]-triazol-5-yl)phenyl]amines. They can act as "building blocks" and allow for the introduction of certain structural motifs into the desired final products in order to enhance the antistaphylococcal effect.
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