The nucleotide excision repair (NER) pathway is critical for removing damage induced by ultraviolet (UV) light and other helix-distorting lesions from cellular DNA. While efficient NER is critical to avoid cell death and mutagenesis, NER activity is inhibited in chromatin due to the association of lesion-containing DNA with histone proteins. Histone acetylation has emerged as an important mechanism for facilitating NER in chromatin, particularly acetylation catalyzed by the Spt-Ada-Gcn5 acetyltransferase (SAGA); however, it is not known if other histone acetyltransferases (HATs) promote NER activity in chromatin. Here, we report that the essential Nucleosome Acetyltransferase of histone H4 (NuA4) complex is required for efficient NER in Saccharomyces cerevisiae. Deletion of the non-essential Yng2 subunit of the NuA4 complex causes a general defect in repair of UV-induced cyclobutane pyrimidine dimers (CPDs) in yeast; in contrast, deletion of the Sas3 catalytic subunit of the NuA3 complex does not affect repair. Rapid depletion of the essential NuA4 catalytic subunit Esa1 using the anchor-away method also causes a defect in NER, particularly at the heterochromatic HML locus. We show that disrupting the Sds3 subunit of the Rpd3L histone deacetylase (HDAC) complex rescued the repair defect associated with loss of Esa1 activity, suggesting that NuA4-catalyzed acetylation is important for efficient NER in heterochromatin.
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http://dx.doi.org/10.1016/j.dnarep.2018.11.006 | DOI Listing |
Small
January 2025
Department of Chemistry, Indian Institute of Technology Guwahati, Guwahati, 781039, India.
Image-guided photodynamic therapy is acknowledged as one of the most demonstrative therapeutic modalities for cancer treatment because of its high precision, non-invasiveness, and improved imaging ability. A series of purely organic photosensitizers denoted as BTMCz, BTMPTZ, and BTMPXZ, have been designed and synthesized and are found to exhibit both thermally activated delayed fluorescence and aggregation-induced emission simultaneously. Experimental and theoretical studies are combined to reveal that modulation of the donor of the photosensitizer enables distinct thermally activated delayed fluorescence via a second-order spin-orbit perturbation mechanism involving lowest singlet charge-transfer and higher-lying triplet locally excited states, respectively.
View Article and Find Full Text PDFCancers (Basel)
December 2024
Institute of Chemical Biology, National Hellenic Research Foundation, 11635 Athens, Greece.
: DNA damage response (DDR) is a network of molecular pathways associated with the pathogenesis and progression of several diseases, as well as the outcome of chemotherapy. Moreover, the intracellular redox status is essential for maintaining cell viability and controlling cellular signaling. Herein, we analyzed DDR signals and redox status in peripheral blood mononuclear cells (PBMCs) from patients with lung cancer with different response rates to platinum-based chemotherapy.
View Article and Find Full Text PDFCyclobutane pyrimidine dimers (CPDs) are formed in DNA following exposure to ultraviolet (UV) light and are mutagenic unless repaired by nucleotide excision repair (NER). It is known that CPD repair rates vary in different genome regions due to transcription-coupled NER and differences in chromatin accessibility; however, the impact of regional chromatin organization on CPD formation remains unclear. Furthermore, nucleosomes are known to modulate UV damage and repair activity, but how these damage and repair patterns are affected by the overarching chromatin domains in which these nucleosomes are located is not understood.
View Article and Find Full Text PDFChemistry
December 2024
Department of Chemistry, Indian Institute of Technology Guwahati, Guwahati, 781039, Assam, India.
Bromine is a significant environmental threat due to its corrosive nature and contribution to ozone layer depletion. It often coexists with iodine and forms interhalogen complexes (IBr), which require an effective and selective bromine adsorption strategy. Leveraging the electrophilic nature of bromine, we designed an electron-rich thiophene-based porous organic polymer (POF-2).
View Article and Find Full Text PDFVet Comp Oncol
December 2024
Radiogenomics Laboratory, Sunnybrook Health Sciences Centre, Toronto, Ontario, Canada.
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