Merrikh, HouraRagheb, Mark Nasef2019-08-142019-08-142019Ragheb_washington_0250E_20111.pdfhttp://hdl.handle.net/1773/44403Thesis (Ph.D.)--University of Washington, 2019Evolution guides all biological phenomena, including the rapid rise of antimicrobial resistance (AMR) in bacterial pathogens. Canonical approaches to combat AMR development, such as the development of new antibiotics have largely failed. Therefore, novel approaches to curb the rise of AMR development are sorely needed. In the first part of this thesis, I will describe work showing that the Mfd translocase protein promotes the rapid evolution of AMR. I find that Mfd promotes evolution and mutagenesis in divergent bacterial pathogens and to diverse classes of antibiotics. In addition, I find that Mfd directly promotes drug-resistance conferring mutations as well as the rise of hypermutator cells, which rapidly acquire resistance. I also find that Mfd requires interactions with RNA polymerase (RNAP) and the nucleotide excision repair (NER) protein UvrA to promote the rapid evolution of resistance. We propose that Mfd may be an ideal drug target to help inhibit the evolution of antibiotic resistance. In the second part of this thesis, I further characterize the in vivo function of Mfd, a long-standing enigma in the field. I identify Mfd as a critical RNAP co-factor in vivo and find that this activity is critical for regulating transcription at sites of highly structured regulatory RNAs. I find that Mfd’s activity at regions expressing structured, regulatory RNAs is essential for cellular viability. Lastly, I find that Mfd promotes mutagenesis at sites containing structured RNAs, linking Mfd-mediated mutagenesis to the evolution of structured RNAs. The work presented in this thesis furthers our understanding of how Mfd promotes AMR development as well as our understanding of how this protein functions in vivo to regulate transcription and influence evolution.application/pdfen-USnoneantibiotic resistanceevolutionmfdRNA secondary structuretranscriptiontuberculosisMolecular biologyMicrobiologyGeneticsMolecular and cellular biologyThesis