The most frequent DNA lesion resulting from an oxidative stress is 7,8-dihydro-8-oxoguanine (8-oxoG). 8-oxoG is a premutagenic base modification due to its capacity to pair with adenine. Thus, the repair of 8-oxoG is critical for the preservation of the genetic information. Nowadays, 8-oxoG is also considered as an oxidative stress-sensor with a putative role in transcription regulation. In mammalian cells, the modified base is excised by the 8-oxoguanine DNA glycosylase (OGG1), initiating the base excision repair (BER) pathway. OGG1 confronts the massive challenge that is finding rare occurrences of 8-oxoG among a million-fold excess of normal guanines. Here, we review the current knowledge on the search and discrimination mechanisms employed by OGG1 to find its substrate in the genome. While there is considerable data from in vitro experiments, much less is known on how OGG1 is recruited to chromatin and scans the genome within the cellular nucleus. Based on what is known of the strategies used by proteins searching for rare genomic targets, we discuss the possible scenarios allowing the efficient detection of 8-oxoG by OGG1.
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http://dx.doi.org/10.3390/ijms21218360 | DOI Listing |
Cells
January 2025
Department of Molecular Medicine and Medical Biotechnologies, University of Naples 'Federico II', 80131 Naples, Italy.
Genomic integrity is critical for cellular homeostasis, preventing the accumulation of mutations that can drive diseases such as cancer. Among the mechanisms safeguarding genomic stability, the Base Excision Repair (BER) pathway plays a pivotal role in counteracting oxidative DNA damage caused by reactive oxygen species. Central to this pathway are enzymes like 8-oxoguanine glycosylase 1 (OGG1), which recognize and excise 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG) lesions, thereby initiating a series of repair processes that restore DNA integrity.
View Article and Find Full Text PDFFront Endocrinol (Lausanne)
January 2025
Facultad de Farmacia y Bioquímica, Departamento de Microbiología, Inmunología, Biotecnología y Genética, Universidad de Buenos Aires, Buenos Aires, Argentina.
Introduction: Polycystic Ovary Syndrome (PCOS) affects 5-20% of reproductive-aged women. Insulin resistance (IR) is common in PCOS with consequent elevated risks of metabolic disorders and cardiovascular mortality. PCOS and obesity are complex conditions associated with Metabolic Syndrome (MS), contributing to cardiovascular disease and type 2 diabetes mellitus (T2D).
View Article and Find Full Text PDFFree 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 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 PDFInvest Ophthalmol Vis Sci
January 2025
Eye Institute, Affiliated Hospital of Nantong University, Medical School of Nantong University, Nantong, Jiangsu, China.
Purpose: To investigate potential modes of programmed cell death in the lens epithelial cells (LECs) of patients with early age-related cortical cataract (ARCC) and to explore early-stage intervention strategies.
Methods: Anterior lens capsules were collected from early ARCC patients for comprehensive analysis. Ultrastructural examination of LECs was performed using transmission electron microscopy.
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