Document Type

Dissertation

Date of Degree

Summer 2017

Access Restrictions

Access restricted until 08/31/2018

Degree Name

PhD (Doctor of Philosophy)

Degree In

Biochemistry

First Advisor

Maria Spies

Abstract

Defects in BRCA1 and BRCA2 tumor suppressors predispose one to breast and ovarian cancer. The current treatment for BRCA-deficient cancers is mastectomy. Because both copies of the tumor suppressor need to be defective for cancer to occur, identifying cellular mechanisms that specifically target BRCA-deficient cells is of paramount importance. Luckily, recent experiments have shown that depletion of a protein named RAD52 in BRCA1 or BRCA2 cancer cells causes them to die. Therefore, we can use small molecules to stop the RAD52 protein from functioning. We need, however, to know which of the RAD52 activities to inhibit and how. One function of RAD52 that likely underlies all cellular activities is its ability to bind single-stranded DNA (ssDNA). To identify if small molecules could inhibit the RAD52-ssDNA complex, I screened a small library of compounds and found 13 potential inhibitors. We validated that these small molecules bind to RAD52 and inhibit RAD52 DNA binding and annealing activities. The identification of these small molecules is important because we can use them to dissect the function of RAD52 in normal and malignant cells, which to date remains elusive.

In an attempt to further advance our understanding of RAD52 function and regulation we are also investigating how a novel binding partner, DSS1, interacts with RAD52 and modulates its activities. My data show that this protein enhances the way RAD52 finds separate complementary DNA templates and anneals them to make a double-stranded product. At least in part, these studies have identified some residues likely involved in the binding site of DSS1 on RAD52. In aggregate, the outcome of the two projects deepens our understanding of the complex and interconnected cellular pathways that support the integrity of genomes.

Keywords

DSS1, Inhibitors, RAD52, ssDNA

Pages

xv, 150 pages

Bibliography

Includes bibliographical references (pages 142-150).

Comments

This thesis has been optimized for improved web viewing. If you require the original version, contact the University Archives at the University of Iowa: http://www.lib.uiowa.edu/sc/contact/

Copyright

Copyright © 2017 Sarah Ruth Hengel

Available for download on Friday, August 31, 2018

Included in

Biochemistry Commons

Share

COinS