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Genomic integrity depends on the RecA/RAD51 protein family. Discovered over five decades ago with the founder bacterial RecA protein, eukaryotic RAD51 is an ATP-dependent DNA strand transferase implicated in DNA double-strand break and single-strand gap repair, and in dealing with stressed DNA replication forks. RAD51 assembles as a nucleoprotein filament around single-stranded DNA to promote homology recognition in a duplex DNA and subsequent strand exchange. While the intrinsic dynamics of the RAD51 nucleoprotein filament has been extensively studied, a plethora of accessory factors control its dynamics. Understanding how modulators control filament dynamics is at the heart of current research efforts. Here, we describe recent advances in RAD51 control mechanisms obtained specifically using fluorescence-based single-molecule techniques.
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http://dx.doi.org/10.1016/j.gde.2021.09.001 | DOI Listing |
Int J Mol Sci
August 2025
Research Center of Nanobiotechnologies, Peter the Great St. Petersburg Polytechnic University, Polytechnicheskaya, 29, 195251 St. Petersburg, Russia.
DprA (also known as Smf) is a conserved RecA mediator originally characterized by its role in natural chromosomal transformation, yet its widespread presence across bacteria hints at broader DNA metabolic functions. Here, we demonstrate that DprA enhances the frequency of Hfr conjugation in vivo. In vitro, RecA·ATP binds and cooperatively polymerizes in a 50-nucleotide (nt) polydeoxy T (dT) ssDNA to form dynamic filaments that SSB inhibits, an effect fully reversed by DprA.
View Article and Find Full Text PDFElife
August 2025
Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom.
Homologous recombination (HR) preserves genomic stability by repairing double-strand DNA breaks and ensuring efficient DNA replication. Central to HR is the strand-exchange reaction taking place within the three-stranded synapsis wherein a RAD51 nucleoprotein filament binds to a donor DNA. Here, we present the cryoEM structure of a displacement loop of human RAD51 that captures the synaptic state when the filament has become tightly bound to the donor DNA.
View Article and Find Full Text PDFNat Commun
August 2025
Department of Microbiology-Immunology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA.
Human cytomegalovirus extensively alters nuclear organization and the cellular transcriptome, yet understanding of these genome-wide events remains relatively limited. Here, chromatin conformation capture (Hi-C) revealed how cytomegalovirus alters chromosome organization at both large- and small-scales. Nascent transcriptomics further revealed how transcriptional changes correlate with genomic reorganization, while also uncovering infection-induced transcriptional dysregulation that contributes to the induction of neuronal gene signatures in infected fibroblasts.
View Article and Find Full Text PDFNucleic Acids Res
July 2025
Biophysics and Structural Genomics Division, Saha Institute of Nuclear Physics, Kolkata 700064, West Bengal, India.
Lamins are intermediate filaments constituting the nuclear lamina which maintains the structural integrity of the nucleus and play a key role in the spatiotemporal genome organization. Mutations in lamin A/C have been associated with a plethora of diseases including dilated cardiomyopathy. In this study, we focused on lamin A mutants E161K and K97E which are widely reported in patients afflicted with dilated cardiomyopathy.
View Article and Find Full Text PDFOpen Biol
August 2025
Institute of Parasitology, Biology Centre, Czech Academy of Sciences, České Budějovice, Czech Republic.
Diplonemids are highly diverse and abundant marine plankton with significant ecological importance. However, little is known about their biology, even in the model diplonemid whose genome sequence is available. Examining the subcellular localization of proteins using fluorescence microscopy is a powerful approach to infer their putative function.
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