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Biochemistry

Florida International University

FEN1

Publication Year

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Full-Text Articles in Life Sciences

Dna Base Excision Repair Modulates Dna Repeat Instability And Non-B Form Dna Structures, Eduardo E. Laverde Mar 2020

Dna Base Excision Repair Modulates Dna Repeat Instability And Non-B Form Dna Structures, Eduardo E. Laverde

FIU Electronic Theses and Dissertations

The human genome is constantly attacked by endogenous and exogenous sources of DNA damage that generates DNA base lesions and strand breaks leading to genome instability, cell death, and diseases. To combat these adverse effects, cells have evolved a robust DNA repair mechanism called “the DNA base excision repair (BER),” which efficiently removes DNA lesions maintaining genome stability. However, its underlying molecular mechanisms remain to be elucidated. In my dissertation research, I explored the molecular mechanism by which BER modulates trinucleotide repeats (TNR) by processing non-B form structures such as hairpins and R-loops through the coordination among BER enzymes and …


Trinucleotide Repeat Instability Modulated By Dna Repair Enzymes And Cofactors, Yaou Ren May 2018

Trinucleotide Repeat Instability Modulated By Dna Repair Enzymes And Cofactors, Yaou Ren

FIU Electronic Theses and Dissertations

Trinucleotide repeat (TNR) instability including repeat expansions and repeat deletions is the cause of more than 40 inherited incurable neurodegenerative diseases and cancer. TNR instability is associated with DNA damage and base excision repair (BER). In this dissertation research, we explored the mechanisms of BER-mediated TNR instability via biochemical analysis of the BER protein activities, DNA structures, protein-protein interaction, and protein-DNA interaction by reconstructing BER in vitro using synthesized oligonucleotide TNR substrates and purified human proteins. First, we evaluated a germline DNA polymerase β (pol β) polymorphic variant, pol βR137Q, in leading TNR instability-mediated cancers or neurodegenerative diseases. We find …