Chromosomal single-strand breaks (SSBs) are the most common lesions arising in cells, but are normally rapidly repaired by multiprotein complexes centered around the scaffold protein, XRCC1. Here, we describe protocols to measure chromosomal SSBs in cells and for recovering and identifying novel components of SSBR complexes in vitro and in vivo. We also describe an assay we employ to measure the rate of replication fork progression in mammalian/vertebrate cells in the presence or absence of DNA damage.
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http://dx.doi.org/10.1016/S0076-6879(05)09024-5 | DOI Listing |
Nat Cell Biol
January 2025
Genome Integrity Unit, Children's Medical Research Institute, University of Sydney, Westmead, New South Wales, Australia.
Double-strand breaks (DSBs) can initiate mitotic catastrophe, a complex oncosuppressive phenomenon characterized by cell death during or after cell division. Here we unveil how cell cycle-regulated DSB repair guides disparate cell death outcomes through single-cell analysis of extended live imaging. Following DSB induction in S or G2, passage of unresolved homologous recombination intermediates into mitosis promotes non-immunogenic intrinsic apoptosis in the immediate attempt at cell division.
View Article and Find Full Text PDFDefects in DNA single-strand break repair are associated with neurodevelopmental and neurodegenerative disorders. One such disorder is that resulting from mutations in , a scaffold protein that plays a central role in DNA single-strand base repair. XRCC1 is recruited at sites of single-strand breaks by PARP1, a protein that detects and is activated by such breaks and is negatively regulated by XRCC1 to prevent excessive PARP binding and activity.
View Article and Find Full Text PDFNucleic Acids Res
January 2025
Department of Convergent Bioscience and Informatics, College of Bioscience and Biotechnology, Chungnam National University, 99, Daehak-ro, Yuseong-gu, Daejeon 34134, Republic of Korea.
Large genetic variants can be generated via homologous recombination (HR), such as polymerase theta-mediated end joining (TMEJ) or single-strand annealing (SSA). Given that these HR-based mechanisms leave specific genomic signatures, we developed GDBr, a genomic signature interpretation tool for DNA double-strand break repair mechanisms using high-quality genome assemblies. We applied GDBr to a draft human pangenome reference.
View Article and Find Full Text PDFInt J Mol Sci
December 2024
Ocular Genomics Institute, Massachusetts Eye and Ear Infirmary, Department of Ophthalmology, Harvard Medical School, Boston, MA 02114, USA.
Prime editing (PE) is a CRISPR-based tool for genome engineering that can be applied to generate human induced pluripotent stem cell (hiPSC)-based disease models. PE technology safely introduces point mutations, small insertions, and deletions (indels) into the genome. It uses a Cas9-nickase (nCas9) fused to a reverse transcriptase (RT) as an editor and a PE guide RNA (pegRNA), which introduces the desired edit with great precision without creating double-strand breaks (DSBs).
View Article and Find Full Text PDFEJNMMI Radiopharm Chem
January 2025
Division of Nuclear Medicine, Department of Biomedical Imaging and Image-Guided Therapy, Medical University of Vienna, Vienna, Austria.
Background: Poly (ADP-ribose) polymerase (PARP) enzymes are crucial for the repair of DNA single-strand breaks and have become key therapeutic targets in homologous recombination-deficient cancers, including prostate cancer. To enable non-invasive monitoring of PARP-1 expression, several PARP-1-targeting positron emission tomography (PET) tracers have been developed. Here, we aimed to preclinically investigate [carbonyl-C]DPQ as an alternative PARP-1 PET tracer as it features a strongly distinct chemotype compared to the frontrunners [F]FluorThanatrace and [F]PARPi.
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