Protein modification by ubiquitin is emerging as a signal for various biological processes in eukaryotes, including regulated proteolysis, but also for non-degradative functions such as protein localization, DNA repair and regulation of chromatin structure. A small ubiquitin-related modifier (SUMO) uses a similar conjugation system that sometimes counteracts the effects of ubiquitination. Ubiquitin and SUMO compete for modification of proliferating cell nuclear antigen (PCNA), an essential processivity factor for DNA replication and repair. Whereas multi-ubiquitination is mediated by components of the RAD6 pathway and promotes error-free repair, SUMO modification is associated with replication. Here we show that RAD6-mediated mono-ubiquitination of PCNA activates translesion DNA synthesis by the damage-tolerant polymerases eta and zeta in yeast. Moreover, polymerase zeta is differentially affected by mono-ubiquitin and SUMO modification of PCNA. Whereas ubiquitination is required for damage-induced mutagenesis, both SUMO and mono-ubiquitin contribute to spontaneous mutagenesis in the absence of DNA damage. Our findings assign a function to SUMO during S phase and demonstrate how ubiquitin and SUMO, by regulating the accuracy of replication and repair, contribute to overall genomic stability.
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http://dx.doi.org/10.1038/nature01965 | DOI Listing |
Nature
January 2025
Laboratory of Gene Regulation and Signal Transduction, Departments of Pharmacology and Pathology, School of Medicine, University of California San Diego (UCSD), La Jolla, CA, USA.
J Biol Chem
December 2024
SAMRC/NHLS/UCT Molecular Mycobacteriology Research Unit, DSI/NRF Centre of Excellence for Biomedical TB Research, Department of Pathology, University of Cape Town, Cape Town, South Africa; Institute of Infectious Disease and Molecular Medicine, University of Cape Town, Cape Town, South Africa. Electronic address:
The mycobacterial mutasome-comprising ImuA', ImuB, and DnaE2-has been implicated in DNA damage-induced mutagenesis in Mycobacterium tuberculosis. ImuB, which is predicted to enable mutasome function via its interaction with the β clamp, is a catalytically inactive Y-family DNA polymerase. Like some other members of the Y-family, ImuB features a recently identified amino acid motif with homology to the RecA N terminus (RecA-NT).
View Article and Find Full Text PDFNPJ Antimicrob Resist
November 2024
Department of Molecular and Cellular Biology, University of Guelph, Guelph, ON N1H 5N4 Canada.
Antimicrobial-induced DNA damage, and subsequent repair via upregulation of DNA repair factors, including error-prone translesion polymerases, can lead to the increased accumulation of mutations in the microbial genome, and ultimately increased risk of acquired mutations associated with antimicrobial resistance. While this phenotype is well described in bacterial species, it is less thoroughly investigated amongst microbial fungi. Here, we monitor DNA damage induced by antifungal agents in the fungal pathogen , and find that commonly used antifungal drugs are able to induce DNA damage, leading to the upregulation of transcripts encoding predicted error-prone polymerases and related factors.
View Article and Find Full Text PDFInt J Mol Sci
October 2024
School of Gerontology, University of Southern California, Los Angeles, CA 90089, USA.
Numerous lines of evidence suggest that DNA damage contributes to the initiation, progression, and severity of neurodegenerative diseases. However, the molecular mechanisms responsible for this relationship remain unclear. This review integrates historical data with contemporary findings to propose that DNA damage exacerbates neurodegenerative diseases by inducing transcription errors.
View Article and Find Full Text PDFNature
June 2024
Medical Research Council Human Genetics Unit, Institute of Genetics and Cancer, University of Edinburgh, Edinburgh, UK.
DNA base damage is a major source of oncogenic mutations. Such damage can produce strand-phased mutation patterns and multiallelic variation through the process of lesion segregation. Here we exploited these properties to reveal how strand-asymmetric processes, such as replication and transcription, shape DNA damage and repair.
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