The induction of premature mitosis by okadaic acid (OA) in HeLa cells in S-phase or in G2-phase has been studied using light microscopy, immunofluorescence, and immunochemical techniques. The observations indicate an involvement of a cdc2-independent pathway in these cells. It has been claimed that inhibition of an OA-sensitive phosphatase, possibly of PP1, induces activation of a kinase which is sensitive to staurosporine and Zn2+. This kinase brings about mitosis-specific cytoskeletal rearrangements, chromosome condensation, and nuclear envelope breakdown, inducing a mitosis-like state. However, other mitotic events do not follow. The possibility that this kinase may be a NIMA-like Nek2 kinase is discussed.
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http://dx.doi.org/10.1006/excr.1998.4115 | DOI Listing |
Proc Natl Acad Sci U S A
January 2025
Department of Human Molecular Genetics and Biochemistry, Faculty of Health & Medical Sciences, Tel Aviv University, Tel Aviv 69978, Israel.
Ataxia-telangiectasia (A-T) is a pleiotropic genome instability syndrome resulting from the loss of the homeostatic protein kinase ATM. The complex phenotype of A-T includes progressive cerebellar degeneration, immunodeficiency, gonadal atrophy, interstitial lung disease, cancer predisposition, endocrine abnormalities, chromosomal instability, radiosensitivity, and segmental premature aging. Cultured skin fibroblasts from A-T patients exhibit premature senescence, highlighting the association between genome instability, cellular senescence, and aging.
View Article and Find Full Text PDFBiomolecules
November 2024
Molecular Toxicology Group, Department of Biology, University of Konstanz, 78457 Konstanz, Germany.
Chronic stress is associated with a higher risk for carcinogenesis as well as age-related diseases and immune dysfunction. There is evidence showing that psychological stress can contribute to premature immunosenescence. Therefore, the question arose whether chronic exposure to catecholamine could drive immune cells into senescence.
View Article and Find Full Text PDFEssential genes, estimated at approximately 20% of the genome, are broadly expressed and required for reproductive success. They are difficult to study, as interfering with their function leads to premature death. Transcription is one of the essential functions of life, and the multi-protein Mediator complex coordinates the regulation of gene expression at nearly every eukaryotic promoter.
View Article and Find Full Text PDFJ Obstet Gynaecol Res
January 2025
Department of Obstetrics and Gynecology, Health Sciences University, Tepecik Education and Research Hospital, Izmir, Turkey.
Aim: This study aims to assess the impacts of various trigger day progesterone (P) and luteinizing hormone (LH) levels on live birth rates (LBRs) in fresh in vitro fertilization (IVF) cycles, considering their elevation from stimulation and premature luteinization.
Methods: This retrospective cohort study included the first ovarian stimulation cycles with GnRH antagonist protocol of 1253 patients who underwent intracytoplasmic sperm injection and fresh embryo transfer at a tertiary clinic's IVF center between 2010 and 2016. Participants were divided into four groups based on trigger day serum P and LH levels, using the 90th percentile thresholds for P (1.
Environ Health Prev Med
January 2025
Health and Environmental Risk Division, National Institute for Environmental Studies.
Background: Chronic arsenite exposure has been known to induce cancer in various organs; however, the underlying mechanisms remain elusive. The characteristic feature of carcinogenesis due to arsenic exposure is that the disease develops after a prolonged latent period, even after cessation of exposure. Our previous study revealed that arsenite exposure induces premature senescence in hepatic stellate cells and suggests that the senescence-associated secretory phenotype (SASP) factors from the senescent cells promote hepatic carcinogenesis.
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