DNA recognition by the BRCA1 tumor suppressor

3^rd International Conference on Molecular Biology & Nucleic Acids

August 27-28, 2018 | Toronto, Canada

Ann J Fuelle, Zhouling He, and Colin G Wu

Oakland University, USA

Posters & Accepted Abstracts: Mol Biol

Abstract :

Statement of the Problem: Human BRCA1 encodes a tumor suppressor protein that repairs double-stranded DNA breaks in cells. Mutations in BRCA1 are closely linked to the early onset of breast and ovarian cancers. BRCA1 protein participates in several DNA repair pathways but the molecular mechanisms through which BRCA1 targets damaged DNA structures is not well-understood. Methodology & Theoretical Orientation: A detailed comparison of the DNA binding preferences of BRCA1 was performed on its DNA binding domains (DBD1 aa330-554, DBD2a aa894-1057, DBD2b aa936-1057, and BRCT aa1745-1861). Each BRCA1 fragment was expressed in E. coli and purified from other proteins using nickel affinity and heparin ion exchange chromatography. The relative affinities of these purified BRCA1 domains for various DNA targets (ssDNA, dsDNA, human G4 telomere, etc.) were measured by biolayer interferometry (BLI) as well as fluorescence spectroscopy. These equilibrium constant values were used to rank order the DNA binding preferences for each protein domain. Findings: We find that DBD1 has the highest affinity for dsDNA. Both DBD2a and DBD2b show the highest affinity for singlestranded DNA, while BRCT binds tightest to the human G4 telomeric sequence. Conclusion & Significance: The modular nature of these BRCA1-DNA interactions may provide a regulatory mechanism to control its DNA repair functions inside the cell. Therefore, we plan to perform DNA repair studies in human cell lines alongside these in vitro binding experiments to further test the link between DNA binding activity and repair of DNA lesions.

Biography :

Ann J Fuelle is currently studying Biomedical Diagnostic and Therapeutic Sciences with concentrations in Medical Laboratory Sciences and Pre-Med studies. She started working in a laboratory at the University of Michigan in 2014 before attending Oakland University in 2016. Zhuoling He is currently studying Biochemistry with a Biology minor. Zhuoling hopes to obtain a PhD degree in the future. Both women work under the direction of Colin G. Wu at Oakland University in the field of Biochemistry studying DNA repair pathways

E-mail: annfuelle@oakland.edu

zhuolinghe@oakland.edu