DNA replication dynamics in cells from higher eukaryotes follows very complex but highly efficient mechanisms. However, the principles behind initiation of potential replication origins and emergence of typical patterns of nuclear replication sites remain unclear. Here, we propose a comprehensive model of DNA replication in human cells that is based on stochastic, proximity-induced replication initiation. Critical model features are: spontaneous stochastic firing of individual origins in euchromatin and facultative heterochromatin, inhibition of firing at distances below the size of chromatin loops and a domino-like effect by which replication forks induce firing of nearby origins. The model reproduces the empirical temporal and chromatin-related properties of DNA replication in human cells. We advance the one-dimensional DNA replication model to a spatial model by taking into account chromatin folding in the nucleus, and we are able to reproduce the spatial and temporal characteristics of the replication foci distribution throughout S-phase.
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http://dx.doi.org/10.1038/ncomms11207 | DOI Listing |
Fish Shellfish Immunol
January 2025
The Laboratory of Aquatic Parasitology and Microbial Resources, School of Marine Science and Engineering, Qingdao Agricultural University, Qingdao, Shandong 266237, China. Electronic address:
Ameson portunus, the causative agent of "toothpaste disease" in Portunus trituberculatus and "slurry-like syndrome" in Scylla paramamosain, has resulted in considerable economic losses in the marine crab aquaculture industry in China. Practical control strategies are yet unavailable. Non-coding RNAs (ncRNAs) are crucial components of gene regulation of intracellular parasites, however, their roles in regulating the microsporidia-host interaction remain limited.
View Article and Find Full Text PDFNucleic Acids Res
January 2025
Université Paris Cité, CNRS, Institut Jacques Monod, F-75013 Paris, France.
Large vertebrate genomes duplicate by activating tens of thousands of DNA replication origins, irregularly spaced along the genome. The spatial and temporal regulation of the replication process is not yet fully understood. To investigate the DNA replication dynamics, we developed a methodology called RepliCorr, which uses the spatial correlation between replication patterns observed on stretched single-molecule DNA obtained by either DNA combing or high-throughput optical mapping.
View Article and Find Full Text PDFNucleic Acids Res
January 2025
Department of Physiology and Biophysics, Virginia Commonwealth University, School of Medicine, Richmond, VA 23298, United States.
The Rep68 protein from Adeno-Associated Virus (AAV) is a multifunctional SF3 helicase that performs most of the DNA transactions necessary for the viral life cycle. During AAV DNA replication, Rep68 assembles at the origin of replication, catalyzing the DNA melting and nicking reactions during the hairpin rolling replication process to complete the second-strand synthesis of the AAV genome. We report the cryo-electron microscopy structures of Rep68 bound to the adeno-associated virus integration site 1 in different nucleotide-bound states.
View Article and Find Full Text PDFJ Biochem
January 2025
Faculty of Science, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan.
SN1-type alkylating reagents generate O6-methylguanine (meG) lesions that activate the mismatch repair (MMR) response. Since post-replicative MMR specifically targets the nascent strand, meG on the template strand is refractory to rectification by MMR and, therefore, can induce non-productive MMR reactions. The cycling of futile MMR attempts is proposed to cause DNA double-strand breaks in the subsequent S phase, leading to ATR-checkpoint-mediated G2 arrest and apoptosis.
View Article and Find Full Text PDFJ Virol
January 2025
Department of Microbiology and Immunology, Dalhousie University, Halifax, Nova Scotia, Canada.
Unlabelled: Coronaviruses have large, positive-sense single-stranded RNA genomes that challenge conventional strategies for mutagenesis. Yeast genetics has been used to manipulate large viral genomes, including those of herpesviruses and coronaviruses. This method, known as transformation-associated recombination (TAR), involves assembling complete viral genomes from dsDNA copies of viral genome fragments via homologous recombination in .
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