UNIVERSITY OF ARIZONA
The overall scope of the parent EUREKA grant is to characterize the structures of G-quadruplex/i-motif complexes found in promoter regions of a number of important genes involved in proliferation, apoptosis, and development, which will serve as a basis for understanding the role of these secondary DNA structures in modulation of gene expression. In this supplementary proposal, we will accelerate the rate of progress on this project by examining a second G-quadruplex/i-motif promoter system as described in the parent EUREKA grant. The two promoter systems, c-Myc for the parent grant and Bcl-2 for this supplement, appear quite different in mechanistic aspects, including structures of the secondary DNA structures and the way in which small molecules and proteins interact with the system.
The specific objectives of this supplement are (1) to follow the conversion of the i-motif to the alternative DNA structure in the presence of an amino steroid (compound 53), (2) to chemically footprint the i-motif in the Bcl-2 promoter under negative supercoiled conditions and determine the effect of compound 53 on the footprinting pattern, and (3) to establish a structureûactivity relationship for steroids that converts the i-motif of the Bcl-2 promoter to an alternative structure and design and synthesize more potent and selective ligands.