DNA damage and secondary structures can stall the replication machinery. Cells possess numerous tolerance mechanisms to complete genome duplication in the presence of such impediments. In addition to translesion synthesis (TLS) polymerases, most eukaryotic cells contain a multifunctional replicative enzyme called primase-polymerase (PrimPol) that is capable of directly bypassing DNA damage by TLS, as well as repriming replication downstream of impediments. Here, we report that PrimPol is recruited to reprime through its interaction with RPA. Using biophysical and crystallographic approaches, we identify that PrimPol possesses two RPA-binding motifs and ascertained the key residues required for these interactions. We demonstrate that one of these motifs is critical for PrimPol's recruitment to stalled replication forks in vivo. In addition, biochemical analysis reveals that RPA serves to stimulate the primase activity of PrimPol. Together, these findings provide significant molecular insights into PrimPol's mode of recruitment to stalled forks to facilitate repriming and restart.
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http://dx.doi.org/10.1038/ncomms15222 | DOI Listing |
Proc Natl Acad Sci U S A
January 2025
Département de Biologie, Université de Sherbrooke, Sherbrooke, QC J1K 2R1, Canada.
To achieve replicative immortality, cancer cells must activate telomere maintenance mechanisms. In 10 to 15% of cancers, this is enabled by recombination-based alternative lengthening of telomeres pathways (ALT). ALT cells display several hallmarks including heterogeneous telomere length, extrachromosomal telomeric repeats, and ALT-associated PML bodies.
View Article and Find Full Text PDFNucleic Acids Res
December 2024
Department of Biology, Tufts University, Suite 4700, 200 Boston Ave, Medford, MA 02155, USA.
Long AT repeat tracts form non-B DNA structures that stall DNA replication and cause chromosomal breakage. AT repeats are abundant in human common fragile sites (CFSs), genomic regions that undergo breakage under replication stress. Using an in vivo yeast model system containing AT-rich repetitive elements from human CFS FRA16D, we find that DNA polymerase zeta (Pol ζ) is required to prevent breakage and subsequent deletions at hairpin and cruciform forming (AT/TA)n sequences, with little to no role at an (A/T)28 repeat or a control non-structure forming sequence.
View Article and Find Full Text PDFGenes Cells
January 2025
School of Science and Technology, Gunma University, Kiryu, Japan.
Sulforaphane (SFN), an isothiocyanate found in plants of the Brassicaceae family, possesses antioxidant, apoptosis-inducing, and radiosensitizing effects. As one of the mechanisms of cytotoxicity by SFN, SFN has been suggested to be involved in the induction of DNA damage and inhibition of DNA repair. Recently, we reported on the potency of SFN in inducing single-ended double-strand breaks (DSBs) that are caused by the collision of replication forks with single-strand breaks (SSBs).
View Article and Find Full Text PDFCancer Metastasis Rev
December 2024
Institute of Chemical Biology and Fundamental Medicine, Novosibirsk, 630090, Russia.
Homologous recombination deficiency (HRD) is considered a universal and effective sign of a tumor's sensitivity to poly(ADP-ribose) polymerase (PARP) inhibitors. HRD diagnostics have undergone several stages of transformations: from detection of point mutations in HR-related genes and large regions with loss of heterozygosity detected using single-nucleotide polymorphism arrays to whole-genome signatures of single-nucleotide variants, large genomic rearrangements (LGRs), and copy number alterations. All these methods have their own advantages and limitations.
View Article and Find Full Text PDFJ Eat Disord
December 2024
Department of Psychiatry and Behavioral Neuroscience, University of Chicago, 5841 S. Maryland Avenue, MC 3077, Chicago, IL, 60637, USA.
Background: Accruing evidence suggests that personality-based approaches to eating disorder classification may offer several advantages over current diagnostic models, with prior research consistently identifying three personality-based groups characterized by either (1) high levels of impulsivity and dysregulation (termed the "undercontrolled" group), (2) high levels of rigidity and avoidance (termed the "overcontrolled" group), or (3) relatively normative levels of personality functioning (termed the "low psychopathology" group). Cognitive inflexibility (i.e.
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