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Full-Text Articles in Pharmacology, Toxicology and Environmental Health

Inhibition Of Rad18 By Arsenic, Lindsay B. Volk Dec 2022

Inhibition Of Rad18 By Arsenic, Lindsay B. Volk

Biomedical Sciences ETDs

Arsenite exposure leads to the retention of UV-induced DNA damage, thus burdening translesion synthesis (TLS). Rad18 is an essential factor in initiating TLS through PCNA monoubiquitination and is implicated in homologous recombination. It contains two functionally and structurally distinct zinc fingers that are potential targets for arsenite binding. Results from this study reveal arsenite binding to both zinc fingers of Rad18 and a corresponding loss of domain function. Importantly, arsenite inhibited Rad18 RING-dependent PCNA monoubiquitination and polymerase eta recruitment to DNA damage. Further analysis demonstrated multiple effects of arsenite, including the reduction in the nuclear localization and UV-induced chromatin recruitment …


Particulate Hexavalent Chromium Inhibits Homologous Recombination Repair By Targeting Rad51 Paralogs In Human Lung Fibroblasts., Aggie R. Williams May 2022

Particulate Hexavalent Chromium Inhibits Homologous Recombination Repair By Targeting Rad51 Paralogs In Human Lung Fibroblasts., Aggie R. Williams

Electronic Theses and Dissertations

Hexavalent Chromium [Cr(VI)] is a known human lung carcinogen and general health hazard. The mechanism of carcinogenesis remains poorly understood, but chromosome instability (CIN) is the major theory in its carcinogenic mechanism. Homologous recombination (HR) repair is a DNA repair pathway that prevents CIN by repairing DNA double-strand breaks. RAD51, a key mediator protein of HR repair, along with the RAD51 paralogs (RAD51B, C, D, XRCC2, and 3) are required for HR repair. During HR, RAD51 loads and forms a helical nucleoprotein filament structure to promote DNA strand exchange and stimulate pairing activity of DNA. Cr(VI) exposures have been shown …