Biomedical Sciences ETDs

Publication Date

12-17-2022

Abstract

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 of Rad18. Arsenite and Rad18 knockdown in UV exposed keratinocytes significantly increased markers of replication stress and DNA strand breaks to a similar degree, suggesting arsenite mediates its effects through Rad18. Altogether, this dissertation supports a mechanism by which arsenite inhibits TLS through the altered activity and regulation of Rad18.

Keywords

Arsenic, cocarcinogenesis, DNA repair, Rad18, translesion synthesis, zinc finger

Sponsors

The National Institutes of Health 1R01ES030993, 1R21ES021499, UNM METALS Superfund Research Program 1P42ES025589, the UNM Center for Metals in Biology and Medicine P20GM130422, the UNM Comprehensive Cancer Center P30CA118100 through Trainee Matching Funds, and the UNMCCC Fluorescence Microscopy and Cell Imaging shared resource

Document Type

Dissertation

Language

English

Degree Name

Biomedical Sciences

Level of Degree

Doctoral

Department Name

Biomedical Sciences Graduate Program

First Committee Member (Chair)

Laurie G. Hudson

Second Committee Member

Mary Ann Osley

Third Committee Member

Alan E. Tomkinson

Fourth Committee Member

Debra Mackenzie

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