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Transcriptional enhancers are brought into proximity with promoters via chromatin looping. The architectural transcription cofactor LDB1 facilitates spatial connectivity among enhancers and promoters but whether this occurs through simple dimerization or requires partner molecules is unknown. Here we investigated single-stranded DNA binding proteins (SSBPs), known LDB1 interactors, in regulating LDB1-mediated chromatin looping and transcription. SSBP2, SSBP3, and SSBP4 colocalize with LDB1 genome wide. Among these, only SSBP3 is essential for erythroid cell viability, LDB1 function, and transcription. LDB1, but not single-stranded DNA, is the predominant genome-wide tether of SSBP3 to chromatin. Notably, SSBP3 depletion for under one hour in SSBP2/4 knockout cells globally weakened LDB1-dependent chromatin loops and lowered nascent transcription without impacting LDB1's chromatin binding. Chromatin tethering experiments revealed SSBP3 and LDB1 mutually depend on each other to form looped contacts. SSBP3 stabilizes LDB1 homodimers in solution providing a possible mechanism of action. In sum, SSBPs emerge as key functional components of the architectural LDB1 complex, shedding new light on the regulation of enhancer-promoter interactions and gene expression.
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http://dx.doi.org/10.1101/2025.06.05.658047 | DOI Listing |
Proc Natl Acad Sci U S A
September 2025
Cancer Research Center of Marseille: Team DNA Damage and Genome Instability|CNRS, Inserm, Institut Paoli-Calmettes, Aix Marseille Université, Marseille 13009, France.
Following encounter with an unrepaired DNA lesion, replication is halted and can restart downstream of the lesion leading to the formation of a single-stranded DNA (ssDNA) gap. To complete replication, this ssDNA gap is filled in by one of the two lesion tolerance pathways: the error-prone Translesion Synthesis (TLS) or the error-free Homology Directed Gap Repair (HDGR). In the present work, we evidence a role for the RecBC complex distinct from its canonical function in homologous recombination at DNA double strand breaks.
View Article and Find Full Text PDFAdv Drug Deliv Rev
September 2025
Biochemistry, CUNY Graduate Center, The City University of New York, 365 Fifth Avenue, New York, NY 10016, United States; Molecular, Cellular, and Developmental Biology, CUNY Graduate Center, The City University of New York, 365 Fifth Avenue, New York, NY 10016, United States; Chemistry, CUNY Gradua
Targeted drug delivery significantly enhances therapeutic efficacy across various diseases, particularly in cancer treatments, where conventional approaches such as chemotherapy and radiotherapy often cause severe side effects. In this context, nucleic acid aptamers-short, single-stranded DNA or RNA oligonucleotides capable of binding specific targets with high affinity-have emerged as promising tools for precision drug delivery and therapy. Aptamers can be selected against whole, living cells using SELEX and chemically modified for diverse applications.
View Article and Find Full Text PDFAnal Chem
September 2025
State Key Laboratory of Physical Chemistry of Solid Surfaces, College of Chemistry and Chemical Engineering, College of Energy, Discipline of Intelligent Instrument and Equipment, State Key Laboratory of Vaccines for Infectious Diseases, Xiang An Biomedicine Laboratory, Xiamen University, Xiamen 361
Rolling circle amplification (RCA) has revolutionized nucleic acid detection owing to its isothermal simplicity. However, over two decades of clinical application have been hampered by off-target amplification and incompatibility with double-stranded DNA (dsDNA). Herein, a strategy, specifically cleavage of rationally designed DNA/RNA chimeric hairpin preprimer by dsDNA-targeted CRISPR/Cas12a to rlease ssRNA for initiating RCA (SCOPE-RCA), is proposed for nucleic acid identification of African swine fever virus (ASFV).
View Article and Find Full Text PDFAnal Chem
September 2025
Laboratory of Organic Chemistry, Department of Chemistry and Applied Biosciences, ETH Zurich, 8093 Zurich, Switzerland.
DNA-encoded libraries have become widely used in drug discovery, and several different setups to link chemical compounds to DNA have been employed in the field, including single-stranded and double-stranded DNA tags as well as a variety of linker chemistries. In our previous study, we observed distinct differences in binding affinities between ligands coupled either to single-stranded or double-stranded DNA; however, the molecular basis for these differences remained unclear. Here, we present a native ion mobility mass spectrometry approach that incorporates gas- and solution-phase activation techniques to systematically investigate these differences, specifically the impact of DNA tags on binding performance in protein-ligand interactions.
View Article and Find Full Text PDFNucleic Acids Res
September 2025
Université Paris-Saclay, INRAE, AgroParisTech, Institut Jean-Pierre Bourgin for Plant Sciences (IJPB), 78000 Versailles, France.
BRCA2 is crucial for mediating homology-directed DNA repair (HDR) through its binding to single-stranded DNA (ssDNA) and the recombinases RAD51 and DMC1. Most BRCA2 orthologs have a canonical DNA-binding domain (DBD) with the exception of Drosophila melanogaster. It remains unclear whether such a noncanonical BRCA2 variant without DBD possesses a DNA-binding activity.
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