Deoxyribose phosphate (dRP) removal by DNA polymerase beta (Pol beta) is a pivotal step in base excision repair (BER). To identify BER cofactors, especially those with dRP lyase activity, we used a Pol beta null cell extract and BER intermediate as bait for sodium borohydride crosslinking. Mass spectrometry identified the high-mobility group box 1 protein (HMGB1) as specifically interacting with the BER intermediate. Purified HMGB1 was found to have weak dRP lyase activity and to stimulate AP endonuclease and FEN1 activities on BER substrates. Coimmunoprecipitation experiments revealed interactions of HMGB1 with known BER enzymes, and GFP-tagged HMGB1 was found to accumulate at sites of oxidative DNA damage in living cells. HMGB1(-/-) mouse cells were slightly more resistant to MMS than wild-type cells, probably due to the production of fewer strand-break BER intermediates. The results suggest HMGB1 is a BER cofactor capable of modulating BER capacity in cells.
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http://dx.doi.org/10.1016/j.molcel.2007.06.029 | DOI Listing |
Free Radic Biol Med
January 2025
Graduate School of Biomedical and Health Sciences, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8553, Japan. Electronic address:
8-Oxo-7,8-dihydroguanine (G, 8-hydroxyguanine), an oxidatively damaged base, induces mutations and is involved in cancer initiation. In addition to G:C→T:A transversions at the damaged site, it causes untargeted base substitution (action-at-a-distance) mutations at the G bases of 5'-GpA-3' sites in human cells. Paradoxically, OGG1, a DNA glycosylase involved in the base excision repair (BER) pathway, enhances the action-at-a-distance mutations by G.
View Article and Find Full Text PDFInt J Biol Macromol
January 2025
College of Environmental Science and Engineering, Yangzhou University, China. Electronic address:
Base deamination can lead to DNA base damage, among which cytosine deamination to uracil occurs frequently. Before repair, replication of uracil in DNA will generate GC → AT transversion mutation. Since base deamination is accelerated by high temperature, genomic DNA stability of hyperthermophiles, which grow optimally above 75 °C, is facing a severe threat by the elevated base deamination created by their living high temperature environments.
View Article and Find Full Text PDFTelomeres are hypersensitive to the formation of the common oxidative lesion 8-oxoguanine (8oxoG), which impacts telomere stability and function. OGG1 and MUTYH glycosylases initiate base excision repair (BER) to remove 8oxoG or prevent mutation. Here, we show OGG1 loss or inhibition, or MUTYH loss, partially rescues telomeric 8oxoG-induced premature senescence and associated proinflammatory responses, while loss of both glycosylases causes a near complete rescue in human fibroblasts.
View Article and Find Full Text PDFMol Cells
January 2025
College of Pharmacy, Graduate School of Pharmaceutical Sciences, Ewha Womans University, Seoul 03760, Republic of Korea; Gradutate Program in Innovative Biomaterials Convergence, Ewha Womans University, Seoul 03760, Republic of Korea. Electronic address:
The base excision repair (BER) pathway is a critical mechanism in genomic stability. This review investigates the role of the BER pathway in advanced cancer therapies considering the pivotal role of genetic factors in cancer patient responses and prognosis. BER factors significantly influence genetic instability and cancer prognosis, as well as the effectiveness of chemotherapy and radiation therapy.
View Article and Find Full Text PDFEnviron Toxicol Pharmacol
January 2025
Department of Zoology, Visva-Bharati, Santiniketan, West Bengal 731235, India. Electronic address:
The present study investigated the individual and mixture effects of Arsenic (As) and Chromium (Cr) at their environmental concentrations in zebrafish (Danio rerio). After 15, 30 and 60 days of exposure, increased frequencies of erythrocytic nuclear abnormalities (ENAs) were noticed. After 60 days of exposure, DNA damage was observed in liver and base excision DNA repair (BER) and mismatch DNA repair (MMR) pathways were studied to know the cellular responses.
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