Repair and replicative DNA synthesis were measured at different stages of the cell cycle in control and cadmium-treated Chinese hamster ovary (CHO-K1) cells. Cells were synchronized by counterflow centrifugal elutriation. Elutriation resulted in five repair and four replication subphases. On Cd treatment, repair synthesis was elevated in certain subphases. Replicative subphases were suppressed by Cd treatment, with some of the peaks almost invisible. The number of spontaneous strand breaks measured by random oligonucleotide primed synthesis assay showed a cell-cycle-dependent fluctuation in control cells and was greatly increased after Cd treatment throughout the S phase. Elevated levels of the oxidative DNA damage product, 8-oxodeoxyguanosine, were observed after Cd treatment, with the highest level in early S phase, which gradually declined as damaged cells progressed through the cell cycle.
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Niger Med J
January 2025
Department of Pathology (Hematology section), Indira Gandhi Institute of Medical Sciences, Patna, India.
Hydroxyurea (HU) is frequently used in the treatment of various myeloproliferative neoplasms (MPN) where it reduces cell proliferation by impairing DNA synthesis leading to decreased hematopoiesis. Herein we report a case of a 65-year-old female who was diagnosed with Chronic myeloid leukemia and developed severe hemolytic anemia requiring multiple packed red blood cell (RBC) transfusions while being treated with hydroxyurea. The haemolysis persisted until discontinuation of the drug.
View Article and Find Full Text PDFBiochem J
January 2025
The Sun Yat-Sen University, Guangzhou, China.
The N6-methyladenine (6mA) modification is an essential epigenetic marker and plays a crucial role in processes, such as DNA repair, replication, gene expression regulation, etc. YerA from Bacillus subtilis is considered a novel class of enzymes capable of catalyzing the deamination of 6mA to produce hypoxanthine. Despite the significance of this type of enzymes in bacterial self-defense systems and potential applications as a gene-editing tool, the substrate specificity, the catalytic mechanism and the physiological function of YerA are currently unclear due to the lack of structural information.
View Article and Find Full Text PDFNucleic Acids Res
January 2025
Laboratory of Genome Regeneration, Institute for Quantitative Biosciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo113-0032, Japan.
DNA copy number changes via chromosomal rearrangements or the production of extrachromosomal circular DNA. Here, we demonstrate that the histone deacetylase Sir2 maintains the copy number of budding yeast ribosomal RNA gene [ribosomal DNA (rDNA)] by suppressing end resection of DNA double-strand breaks (DSBs) formed upon DNA replication fork arrest in the rDNA and their subsequent homologous recombination (HR)-mediated rDNA copy number changes during DSB repair. Sir2 represses transcription from the regulatory promoter E-pro located near the fork arresting site.
View Article and Find Full Text PDFJ Pineal Res
March 2025
College of Enology, Shaanxi Provincial Key Laboratory of Viti-Viniculture, Shaanxi Engineering Research Center of Characteristic Fruit Directional Design and Machining, Northwest A&F University, Yangling, China.
Melatonin is involved in biological adverse stress response and enhances the ability of yeast to adapt to adverse conditions. This study investigated the mechanism of exogenous melatonin addition to Saccharomyces cerevisiae (S. cerevisiae) under copper stress.
View Article and Find Full Text PDFBMC Cancer
January 2025
Department of Laboratory Medicine, Affiliated Gaozhou People's Hospital, Guangdong Medical University, Maoming, 525200, P.R. China.
Background: DNA hypomethylation and uracil misincorporation into DNA, both of which have a very important correlation with colorectal carcinogenesis. Folate plays a crucial role in DNA synthesis, acting as a coenzyme in one-carbon metabolism, which involves the synthesis of purines, pyrimidines, and methyl groups. MTHFR, a key enzyme in folate metabolism, has been widely studied in relation to neural tube defects and hypertension, but its role in colorectal cancer remains underexplored.
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