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The Efficiency Of Dna Repair Processes In Proximity Of G 4 Dna Structures, Gloria Alvarado

Theses and Dissertations

Guanine-rich segments of genomes promote the formation of a four-stranded DNA structure called G-quadruplex (G4 DNA). While evolutionarily conserved, guanine repeats show increased rates of mutagenesis and instability, and this is likely associated with G4 formation. In this thesis, I sought to clarify the molecular sources of genetic instability by testing the repair, excision, and synthesis through guanine-rich DNA. Using E. coli UDG and human SMUG1, I found that uracil is inefficiently repaired in proximity to G4 DNA in vitro. Investigation of E. coli exonuclease III and exonuclease I activity indicated that G4 DNA is a block to activity and …