Biochemistry, Biophysics, and Structural Biology Commons^™

Delineation Of New Mechanisms Of Dna Double Strand Break Repair, Songli Zhu

Theses & Dissertations

DNA damage is frequently induced in cells by both endogenous and exogenous agents. DNA damage, particular double strand breaks (DSBs) may lead to genomic instability, and the progression of cancer, aging, neurodegeneration, and other human diseases. The cell employs two major DSB repair pathways, including homologous recombination (HR) and Non-homologous end joining (NHEJ), but the detailed mechanisms of DSB repair remain to be further revealed.

In the first part of this study, we characterized a plasmid-based assay to investigate NHEJ repair in Xenopus egg extracts. Our data argued for a preference for the precise repair by the NHEJ machinery and …

The Role Of Rad4 In Dna Repair And Its Interplay With Telomeres In Tetrahymena Thermophila, Emily Nischwitz

MSU Graduate Theses

Telomeres are repetitive parts of the genome that act as a protective end cap to the chromosomes. Telomeres are critical to the integrity and stability of the genome, therefore, ensuring that their sequence is maintained, even after damage, is crucial. Much of the pioneering work responsible for explaining telomeres has been conducted in ciliates, specifically in Tetrahymena thermophila. Telomeres in T. thermophila have a high amount of tandem thymine repeats (GGGGTT) and, thus, are susceptible to ultraviolet light (UV) induced lesions called pyrimidine dimers, which must be repaired by nucleotide excision repair (NER). In humans, Xeroderma Pigmentosum C (XPC) …

Investigation Of The Homologs Rad51 And Dmc1 Role In Cell Division And Homologous Recombination, Amaal Abulibdeh

MSU Graduate Theses

RecA-like proteins homologs Rad51 and Dmc1 (disruption of meiotic control) promote recombination between homologous chromosomes by repairing programmed DNA Double-Strand Breaks (DSBs). Dmc1 is a Recombinase involved in meiosis-specific repair of DSBs, whereas Rad51 has been found to be involved in meiotic and non-meiotic DSBs repair. Previous studies showed that when RAD51 is overexpressed, interhomologous recombination still occurs even when DMC1 is knocked out. Dmc1 and Rad51 have not been fully characterized in the ciliate Tetrahymena thermophila. In order to more fully investigate the role of Rad51 and Dmc1 in Homologous Recombination Repair (HHR), this work focuses on using …