Ubiquitination of proliferating-cell nuclear antigen (PCNA) at K164 by RAD6/RAD18 has a key role in DNA damage tolerance in yeast. Here, we report on the first genetic study of this modification in a vertebrate cell. As in yeast, mutation of K164 of PCNA to arginine in the avian cell line DT40 results in sensitivity to DNA damage but, by contrast, the DT40 pcnaK164R mutant is more sensitive than the rad18 mutant. Consistent with this, we show the presence of residual ubiquitination of PCNA at K164 in the absence of functional RAD18, suggesting the presence of an alternate PCNA ubiquitinating enzyme in DT40. Furthermore, RAD18 and PCNA K164 have non-overlapping roles in the suppression of sister chromatid exchange in DT40, showing that RAD18 has other functions that do not involve the ubiquitination of PCNA.
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http://dx.doi.org/10.1038/sj.embor.7400777 | DOI Listing |
Nat Commun
September 2024
Instituto de Biología Molecular y Celular del Cáncer (IBMCC), Universidad de Salamanca-CSIC, Campus Miguel de Unamuno, Salamanca, Spain.
Homologous recombination (HR) and translesion synthesis (TLS) promote gap-filling DNA synthesis to complete genome replication. One factor involved in both pathways is RAD18, an E3 ubiquitin ligase. Although RAD18's role in promoting TLS through the ubiquitination of PCNA at lysine 164 (K164) is well established, its requirement for HR-based mechanisms is currently less clear.
View Article and Find Full Text PDFPNAS Nexus
July 2024
Department of Tumor Biology and Immunology, The Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX Amsterdam, The Netherlands.
The Fanconi anemia (FA) repair pathway governs repair of highly genotoxic DNA interstrand crosslinks (ICLs) and relies on translesion synthesis (TLS). TLS is facilitated by REV1 or site-specific monoubiquitination of proliferating cell nuclear antigen (PCNA) (PCNA-Ub) at lysine 164 (K164). A but not mutation renders mammals hypersensitive to ICLs.
View Article and Find Full Text PDFCell Rep
December 2023
Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA; Department of Biochemistry and Molecular Genetics, University of Virginia, Charlottesville, VA 22903, USA. Electronic address:
Nucleic Acids Res
January 2024
Division of Protein & Nucleic Acid Chemistry, Medical Research Council Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, UK.
The primase/polymerase PRIMPOL restarts DNA synthesis when replication is arrested by template impediments. However, we do not have a comprehensive view of how PRIMPOL-dependent repriming integrates with the main pathways of damage tolerance, REV1-dependent 'on-the-fly' lesion bypass at the fork and PCNA ubiquitination-dependent post-replicative gap filling. Guided by genome-wide CRISPR/Cas9 screens to survey the genetic interactions of PRIMPOL in a non-transformed and p53-proficient human cell line, we find that PRIMPOL is needed for cell survival following loss of the Y-family polymerases REV1 and POLη in a lesion-dependent manner, while it plays a broader role in promoting survival of cells lacking PCNA K164-dependent post-replicative gap filling.
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