DNA-protein crosslinks (DPCs) are toxic lesions that inhibit DNA related processes. Post-translational modifications (PTMs), including SUMOylation and ubiquitylation, play a central role in DPC resolution, but whether other PTMs are also involved remains elusive. Here, we identify a DPC repair pathway orchestrated by poly-ADP-ribosylation (PARylation). Using Xenopus egg extracts, we show that DPCs on single-stranded DNA gaps can be targeted for degradation via a replication-independent mechanism. During this process, DPCs are initially PARylated by PARP1 and subsequently ubiquitylated and degraded by the proteasome. Notably, PARP1-mediated DPC resolution is required for resolving topoisomerase 1-DNA cleavage complexes (TOP1ccs) induced by camptothecin. Using the Flp-nick system, we further reveal that in the absence of PARP1 activity, the TOP1cc-like lesion persists and induces replisome disassembly when encountered by a DNA replication fork. In summary, our work uncovers a PARP1-mediated DPC repair pathway that may underlie the synergistic toxicity between TOP1 poisons and PARP inhibitors.
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http://dx.doi.org/10.1038/s41467-024-50912-x | DOI Listing |
Cell Rep
December 2024
Division of Pulmonary and Critical Care, Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA; Department of Cell and Developmental Biology, Northwestern University Feinberg School of Medicine, Chicago, IL 60611, USA. Electronic address:
Forkhead box P3 (Foxp3) regulatory T cells (Tregs) resolve acute inflammation and repair the injured lung after viral pneumonia. Vimentin is a critical protein in the distal pole complex (DPC) of Tregs. This study reveals the inhibitory effect of vimentin on the suppressive and reparative capacity of Tregs.
View Article and Find Full Text PDFMicroscopy (Oxf)
October 2024
Research and Development Group, Hitachi, Ltd., 2520 Akanuma, Hatoyama, Saitama, 350-0395, Japan.
A simple method that improves the resolution of the phase measurement of differential phase-contrast (DPC) scanning transmission electron microscopy for closed-type environmental cell applications was developed and tested using a model sample simulating environmental cell observations. Because the top and bottom membranes of an environmental cell are typically far apart, the images from these membranes are shifted widely by tilt-series acquisition, and averaging the images after alignment can effectively eliminate undesired signals from the membranes while improving the signal from the object of interest. It was demonstrated that a phase precision of 2π/100 rad is well achievable using the proposed method for the sample in an environmental cell.
View Article and Find Full Text PDFRadiology
September 2024
From the Department of Radiology, Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, 149 Thirteenth St, Ste 2301, Charlestown, MA 02129 (M.B., F.W., Z.D., O.C.A.); Harvard Medical School, Boston, Mass (M.B., F.W., Z.D., J.D., E.J.U., T.T.B., D.P.C., O.C.A.); Department of Neurology, Papas Center for Neuro-Oncology, Massachusetts General Hospital, Boston, Mass (J.D.); Department of Neurology, Beth Israel Deaconess Medical Center, Boston, Mass (E.J.U.); Department of Neurology, Brigham and Women's Hospital, Boston, Mass (T.T.B.); Dana Farber Cancer Institute, Boston, Mass (T.T.B.); and Department of Neurosurgery, Massachusetts General Hospital, Boston, Mass (D.P.C.).
Background: MR spectroscopic imaging (MRSI) can be used to quantify an extended brain metabolic profile but is confounded by changes in tissue water levels due to disease.
Purpose: To develop a fast absolute quantification method for metabolite concentrations combining whole-brain MRSI with echo-planar time-resolved imaging (EPTI) relaxometry in individuals with glioma and healthy individuals.
Materials And Methods: In this prospective study performed from August 2022 to August 2023, using internal water as concentration reference, the MRSI-EPTI quantification method was compared with the conventional method using population-average literature relaxation values.
Microsc Microanal
November 2024
School of Physics, Trinity College Dublin, College Green, Dublin D02 PN40, Ireland.
In the scanning transmission electron microscope, both phase imaging of beam-sensitive materials and characterization of a material's functional properties using in situ experiments are becoming more widely available. As the practicable scan speed of 4D-STEM detectors improves, so too does the temporal resolution achievable for both differential phase contrast (DPC) and ptychography. However, the read-out burden of pixelated detectors, and the size of the gigabyte to terabyte sized data sets, remain a challenge for both temporal resolution and their practical adoption.
View Article and Find Full Text PDFDNA Repair (Amst)
October 2024
Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, US National Institutes of Health, Department of Health and Human Services, Research Triangle Park, NC 27709, United States. Electronic address:
Since the report of "DNA untwisting" activity in 1972, ∼50 years of research has revealed seven topoisomerases in humans (TOP1, TOP1mt, TOP2α, TOP2β, TOP3α, TOP3β and Spo11). These conserved regulators of DNA topology catalyze controlled breakage to the DNA backbone to relieve the torsional stress that accumulates during essential DNA transactions including DNA replication, transcription, and DNA repair. Each topoisomerase-catalyzed reaction involves the formation of a topoisomerase cleavage complex (TOPcc), a covalent protein-DNA reaction intermediate formed between the DNA phosphodiester backbone and a topoisomerase catalytic tyrosine residue.
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