We are studying the structural organization of DNA repair complexes that excise DNA damage and the functional consequences of disrupting these protein-protein interactions by mutation and small molecule inhibitors. Alternative pathways of repair are available for many types of DNA damage, and posttranslational modifications generated in response to DNA damage control the differential assembly of repair complexes, providing a mechanism for regulating pathway choice. Cancer-associated defects in DNA maintenance activities can be exploited therapeutically by targeting the remaining repair activities with mechanism-based inhibitors. Our work focuses on the mechanisms of repairing DNA single strand breaks generated by the base excision and nucleotide excision repair pathways. We are studying the physical assembly of DNA damage excision complexes in vitro and in cultured cells, and the mechanism of coupling DNA cleavage to end processing and ligation. Small angle x-ray scattering of purified DNA repair complexes reveals dynamic conformational states that we propose are important for handoffs of DNA repair intermediates to successive enzymes in a pathway. High resolution crystal structures and small molecule screening experiments are being used to predict and identify inhibitors of repair protein interactions, which are candidates for anti-tumor therapies and serve as reversible chemical probes of cellular physiology during DNA damage responses. This integrated approach takes advantage of the broad expertise of investigators in Projects 1, 2, and 6 for assays and biological materials, as well as the unique capabilities of the Expression and Molecular Biology Core and the Structural Cell Biology Core of the SBDR Program to produce proteins and structurally evaluate repair complexes.
The Achilles'heel of all cancer cells is their defect in DNA repair and cell cycle checkpoints that can kill tumor cells by causing them to enter cell division before repair is complete. Thus, many cancers are treated by radiation and chemotherapies to overload repair in tumor cells but not in normal cells, which are better protected by redundant repair pathways and functioning cell cycle checkpoints. SBDR will comprehensively characterize DNA repair circuits to reveal tumor vulnerabilities that are key to short-circuiting DNA repair and specifically killing cancer cells while not harming better-protected normal cells.
|Polyzos, Aris A; Wood, Nigel I; Williams, Paul et al. (2018) XJB-5-131-mediated improvement in physiology and behaviour of the R6/2 mouse model of Huntington's disease is age- and sex- dependent. PLoS One 13:e0194580|
|Schneidman-Duhovny, Dina; Hammel, Michal (2018) Modeling Structure and Dynamics of Protein Complexes with SAXS Profiles. Methods Mol Biol 1764:449-473|
|Sung, Patrick (2018) Introduction to the Thematic Minireview Series: DNA double-strand break repair and pathway choice. J Biol Chem 293:10500-10501|
|Shen, Jianfeng; Ju, Zhenlin; Zhao, Wei et al. (2018) ARID1A deficiency promotes mutability and potentiates therapeutic antitumor immunity unleashed by immune checkpoint blockade. Nat Med 24:556-562|
|Sengupta, Shiladitya; Yang, Chunying; Hegde, Muralidhar L et al. (2018) Acetylation of oxidized base repair-initiating NEIL1 DNA glycosylase required for chromatin-bound repair complex formation in the human genome increases cellular resistance to oxidative stress. DNA Repair (Amst) 66-67:1-10|
|Mu, Hong; Geacintov, Nicholas E; Broyde, Suse et al. (2018) Molecular basis for damage recognition and verification by XPC-RAD23B and TFIIH in nucleotide excision repair. DNA Repair (Amst) :|
|Chavez, Diana A; Greer, Briana H; Eichman, Brandt F (2018) The HIRAN domain of helicase-like transcription factor positions the DNA translocase motor to drive efficient DNA fork regression. J Biol Chem 293:8484-8494|
|Wang, Jing L; Duboc, Camille; Wu, Qian et al. (2018) Dissection of DNA double-strand-break repair using novel single-molecule forceps. Nat Struct Mol Biol 25:482-487|
|Crickard, J Brooks; Kaniecki, Kyle; Kwon, Youngho et al. (2018) Meiosis-specific recombinase Dmc1 is a potent inhibitor of the Srs2 antirecombinase. Proc Natl Acad Sci U S A 115:E10041-E10048|
|Syed, Aleem; Tainer, John A (2018) The MRE11-RAD50-NBS1 Complex Conducts the Orchestration of Damage Signaling and Outcomes to Stress in DNA Replication and Repair. Annu Rev Biochem 87:263-294|
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