In their influential reviews, Hanahan and Weinberg coined the term 'Hallmarks of Cancer' and described genome instability as a property of cells enabling cancer development. Accurate DNA replication of genomes is central to diminishing genome instability. Here, the understanding of the initiation of DNA synthesis in origins of DNA replication to start leading strand synthesis and the initiation of Okazaki fragment on the lagging strand are crucial to control genome instability. Recent findings have provided new insights into the mechanism of the remodelling of the prime initiation enzyme, DNA polymerase α-primase (Pol-prim), during primer synthesis, how the enzyme complex achieves lagging strand synthesis, and how it is linked to replication forks to achieve optimal initiation of Okazaki fragments. Moreover, the central roles of RNA primer synthesis by Pol-prim in multiple genome stability pathways such as replication fork restart and protection of DNA against degradation by exonucleases during double-strand break repair are discussed.
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http://dx.doi.org/10.3390/genes14051012 | DOI Listing |
Mol Microbiol
December 2024
CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Université Paris-Saclay, Gif-sur-Yvette, France.
DNA topology is a direct consequence of the double helical nature of DNA and is defined by how the two complementary DNA strands are intertwined. Virtually every reaction involving DNA is influenced by DNA topology or has topological effects. It is therefore of fundamental importance to understand how this phenomenon is controlled in living cells.
View Article and Find Full Text PDFGenetics
December 2024
Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, SC 29425, USA.
Acetaldehyde is the primary metabolite of alcohol and is present in many environmental sources including tobacco smoke. Acetaldehyde is genotoxic, whereby it can form DNA adducts and lead to mutagenesis. Individuals with defects in acetaldehyde clearance pathways have increased susceptibility to alcohol-associated cancers.
View Article and Find Full Text PDFDNA Repair (Amst)
November 2024
Department of Biochemistry, University of Western Ontario, London, Ontario N6A 5C1, Canada. Electronic address:
Rad51 filaments are Rad51-coated single-stranded DNA and essential in homologous recombination (HR). The yeast Shu complex (Shu) is a conserved regulator of homologous recombination, working through its modulation on Rad51 filaments to direct HR-associated DNA damage response. However, the biochemical properties of Shu remain unclear, which hinders molecular insights into Shu's role in HR and the DNA damage response.
View Article and Find Full Text PDFMol Cell
November 2024
Department of Medicine, Division of Hematology-Oncology and Cancer Research Institute, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA 02215, USA. Electronic address:
Replication fork collision with a DNA nick can generate a one-ended break, fostering genomic instability. The opposing fork's collision with the nick could form a second DNA end, enabling conservative repair by homologous recombination (HR). To study mechanisms of nickase-induced HR, we developed the Flp recombinase "step arrest" nickase in mammalian cells.
View Article and Find Full Text PDFMol Cell
November 2024
Department of Microbiology & Immunology, Columbia University Irving Medical Center, New York, NY 10032, USA; Department of Genetics & Development, Columbia University Irving Medical Center, New York, NY 10032, USA. Electronic address:
Single-strand breaks (SSBs) are one of the most commonly occurring endogenous lesions with the potential to give rise to cytotoxic double-strand breaks (DSBs) during DNA replication. To investigate how replication-dependent DSBs are repaired, we employed Cas9 nickase (nCas9) to generate site- and strand-specific nicks in the budding yeast genome. We found that nCas9-induced nicks are converted to mostly double-ended DSBs during S phase.
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