Indiana University-Purdue University Indianapolis (IUPUI) / In mammalian cells DNA double strand breaks (DSBs) are highly variable with respect to sequence and structure all of which are recognized by the DNA- dependent protein kinase (DNA-PK), a critical component for the resolution of these breaks. Previously studies have shown that DNA-PK does not respond the same way to all DSBs but how DNA-PK senses differences in DNA substrate sequence and structure is unknown. Here we explore the enzymatic mechanism by which DNA-PK is activated by various DNA substrates. We provide evidence that recognition of DNA structural variations occur through distinct protein-protein interactions between the carboxy terminal (C-terminal) region of Ku80 and DNA-dependent protein kinase catalytic subunit (DNA-PKcs). Discrimination of terminal DNA sequences, on the other hand, occurs independently of Ku 80 C-terminal interactions and results exclusively from DNA-PKcs interactions with the DNA. We also show that sequence differences in DNA termini can drastically influence DNA repair through altered DNA-PK activation. Our results indicate that even subtle differences in DNA substrates influence DNA-PK activation and ultimately Non-homologous End Joining (NHEJ) efficiency.
| Identifer | oai:union.ndltd.org:IUPUI/oai:scholarworks.iupui.edu:1805/4665 |
| Date | 11 July 2014 |
| Creators | Woods, Derek S. |
| Contributors | Turchi, John J., Harrington, Maureen A., Malkova, Anna L., Takagi, Yuichiro |
| Source Sets | Indiana University-Purdue University Indianapolis |
| Language | en_US |
| Detected Language | English |
| Type | Thesis |
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