RecQ helicases are critical for maintaining genomic integrity. In this study, we show that three RecQ members (WRN, deficient in the Werner syndrome; BLM, deficient in the Bloom syndrome; and Drosophila melanogaster RecQ5b (dmRecQ5b)) possess a novel strand pairing activity. Furthermore, each of these enzymes combines this strand pairing activity with its inherent DNA unwinding capability to perform coordinated strand exchange. In this regard, WRN and BLM are considerably more efficient than dmRecQ5b, apparently because dmRecQ5b lacks conserved sequences C-terminal to the helicase domain that contribute to DNA binding, strand pairing, and strand exchange. Based on our findings, we postulate that certain RecQ helicases are structurally designed to accomplish strand exchange on complex replication and recombination intermediates. This is highly consistent with proposed roles for RecQ members in DNA metabolism and the illegitimate recombination and cancer-prone phenotypes associated with RecQ defects.
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http://dx.doi.org/10.1074/jbc.M414130200 | DOI Listing |
Int J Pharm
January 2025
Center for Biopharmaceuticals and Biobarriers in Drug Delivery (BioDelivery), Department of Pharmacy, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, DK-2100 Copenhagen, Denmark. Electronic address:
Oligonucleotides represent a class of molecules that exhibit remarkable therapeutic potential due to their unparalleled target specificity, yet they suffer from limited cellular uptake and lack of tissue selectivity. Extensive research is conducted with cell-penetrating peptides (CPPs) as delivery excipients due to their ability to translocate across cellular membranes and deliver cargo into cells. This study aims to investigate an innovative approach to rapidly, and with small amounts of compound, analyze and compare complexation of CPPs to oligonucleotides.
View Article and Find Full Text PDFActa Histochem
January 2025
School of Chemistry, University of Glasgow, Glasgow G12 8QQ, UK.
In recent years, a great interest has been focused on the prebiotic origin of nucleic acids and life on Earth. An attractive idea is that life was initially based on an autocatalytic and autoreplicative RNA (the RNA-world). RNA duplexes are right-handed helical chains with antiparallel orientation, but the rationale for these features is not yet known.
View Article and Find Full Text PDFJ Phys Chem B
January 2025
OncoImmunin, Inc., 207A Perry Parkway, Suite 6, Gaithersburg, Maryland 20877, United States.
We have previously found that the presence of an H-type excitonic dimer formed by two fluorophores covalently bound to an oligonucleotide allows the delivery of such a polymer into live cells without inducing toxicity. We are now using time-resolved fluorescence measurements in solution to understand the molecular dynamics of an antisense probe and how pairing with complementary sense strands of various lengths and degrees of complementarity affects the antisense strand's properties. We report that a DNA strand composed of 30 residues and labeled with an H-type excitonic Cyanine-5/Cyanine-5 dimer shows a predominant 1.
View Article and Find Full Text PDFGenes (Basel)
November 2024
Departamento de Biología, Universidad Autónoma de Madrid, 28049 Madrid, Spain.
Background/objectives: We analyzed the relationship between synapsis, recombination, and transcription during the spermatogenesis of the grasshopper carrying B chromosomes (type B1).
Methods: The progression of synapsis was interpreted according to the dynamics of the cohesin subunit SMC3 axes. DNA double-strand breaks were revealed by RAD51 immunolabeling, while transcriptional activity was determined by the presence of RNA polymerase II phosphorylated at serine 2 (pRNApol II) immunolabeling.
Biomolecules
November 2024
Department of Chemistry and Chemical Biology, Rutgers University, 123 Bevier Rd, Piscataway, NJ 08854, USA.
We demonstrate that a short oligonucleotide complementary to a G-quadruplex domain can invade this iconic, noncanonical DNA secondary structure in ways that profoundly influence the properties and differential occupancies of the resulting DNA polymorphic products. Our spectroscopic mapping of the conformational space of the associated reactants and products, both before and after strand invasion, yield unanticipated outcomes which reveal several overarching features. First, strand invasion induces the disruption of DNA secondary structural elements in both the invading strand (which can assume an iDNA tetrad structure) and the invaded species (a G-quadruplex).
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