We have tested the ability of mutants of three additional genes in the excision repair pathway of Saccharomyces cerevisiae to suppress the hyper-recombination and rad52 double-mutant lethality phenotypes of the rad3-102 (formerly rem1-2) mutation. Such suppression has previously been observed with mutant alleles of RAD1 and RAD4. We had hypothesized that the rad3-102 mutation created elevated levels of DNA lesions which could be processed by the products of the RAD1 and RAD4 genes into recombinogenic double-strand breaks requiring the RAD52 product for repair. In this report, we show that the RAD2, RAD7, and RAD10 genes are also necessary for this processing. We discuss our observations of varying levels of mitotic crossing-over in Rem- rad double-mutant strains.
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Nat Rev Cancer
January 2025
Translational Oncogenomics Laboratory, Cancer Research UK Manchester Institute, University of Manchester, Manchester, UK.
Intratumour hypoxia is a feature of all heterogenous solid tumours. Increased levels or subregions of tumour hypoxia are associated with an adverse clinical prognosis, particularly when this co-occurs with genomic instability. Experimental evidence points to the acquisition of DNA and chromosomal alterations in proliferating hypoxic cells secondary to inhibition of DNA repair pathways such as homologous recombination, base excision repair and mismatch repair.
View Article and Find Full Text PDFChem Asian J
January 2025
Indian Institute of Science Education and Research Bhopa;, Chemistry, IISER Bhopal, Chemistry, #229,, Academic Building #2, Bhopal bypass road, Bhauri, 462066, Bhopal, INDIA.
Polymerases erroneously incorporate Guanine-Thymine (dG•dT) mismatches in genomic DNA that further evades repair by transient sampling of tautomeric/ionic states compromising fidelity of repairing dG•dT mismatches. In conjunction, significant frequency of ribose (mis)incorporation in duplex DNA permits for misincorporated-mismatch in the genome. Ribose incorporated G(rG) mismatched with T(rG•dT) is the most stable across all misincorporated-mismatch calling into question the conformational consequences of the ribose sugar in addition to the mismatch.
View Article and Find Full Text PDFApurinic/Apyrimidinic (AP)-sites are common and highly mutagenic DNA lesions that can arise spontaneously or as intermediates during Base Excision Repair (BER). The enzyme apurinic/apyrimidinic endonuclease 1 (APE1) initiates repair of AP-sites by cleaving the DNA backbone at the AP-site via its endonuclease activity. Here, we investigated the functional role of the APE1 active site residue N174 that contacts the AP-site during catalysis.
View Article and Find Full Text PDFEur J Ophthalmol
January 2025
Department of Ophthalmology, College of Medicine, King Saud University Medical City, King Saud University, Riyadh, Saudi Arabia.
Purpose: This report presents two cases of orbital textiloma resulting from retained surgical gauze.
Case Description: Both patients presented with postoperative orbital inflammation unresponsive to medical treatment: one eight weeks after excision of an orbital cavernous hemangioma, and the other six months following surgical repair of an orbital floor fracture. CT scans of the orbit revealed well-defined lesions with a heterogeneous center.
Mol Plant
January 2025
State Key Laboratory of Wheat Improvement, School of Advanced Agricultural Sciences, Peking University, Beijing 100871, China; Beijing Life Science Academy, Beijing 102299, China. Electronic address:
It has been hypothesized that DNA damage has the potential to induce DNA hypermethylation, contributing to carcinogenesis in mammals. However, there is no sufficient evidence to support that DNA damage can cause genome-wide DNA hypermethylation. Here, we demonstrated that DNA single-strand breaks with 3'-blocked ends (DNA 3'-blocks) can not only reinforce DNA methylation at normally methylated loci but also can induce DNA methylation at normally nonmethylated loci in plants.
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