Developing Novel Short Peptides to Target G-quadruplex Structure and Modulate Gene Function

G-quadruplexes (G4s) are unconventional nucleic acid structures that have been reported in vitro and in cells. Cumulating studies showed that these non-canonical structural motifs have regulatory roles in a number of fundamental biological processes in cells, but challenges remain in selective targeting of biological-important G4 structures and modulate the G4-linked biological activities. To overcome this, the development of novel G4 targeting strategy and tool — specifically with the capability to target G4 structure over non-G4 structures, as well as the potential to regulate G4-associated gene functions — are two significant areas forfurther uncovering G4 biology and inventing innovative methods for G4 targeting and gene control.Our group have been at the forefront of mapping, characterization, and targeting of G4. Recently, we have identified and characterized DNA and RNA G4s in human, mouse, plants, bacteria, plasmodium, and virus, providing a repertoire of functional G4s for further mechanistic studies and targeting. Lately, we have developed and applied a new toolset, G4-targeting Laptamer,to recognize G4 with strong affinity and specificity successfully, and control G4-protein interactions and G4-mediated gene activity effectively. As a new exploration, we are motivated to develop another novel toolset, G4-targeting peptide, by employing innovative peptide selection platform. In this project, we will develop mRNA display method for G4 target and evolve novel short peptides to target G4 structure. Also, we will examine the G4 affinity and selectivity of selected peptides, and optimize the G4 binding and peptide stability. Last, we will investigate the effect of optimized peptide in modulating G4-protein association and G4-linked gene function.Our team have all the needed instrumentation and skillsets to carry out the tasks in this research program, and the original platform and peptides developed in this project, such as the peptide selection method, peptide sequences, will be patent-worthy. Specific G4targets of interest include the G4s at the 5’ end of human hTERC RNA that is related to telomere maintenance, as well as promoter of human hras-1 gene that are linked to cancers. Other functional G4s will also be studied. Our initial experiments show that the peptide selection strategy is effective and the preliminary data on the peptide candidates are promising, and our team will continue to work well together to ensure successful completion of this timely and stimulating project. We think the outcomes of this project will produce significant and profound insights into the understanding and regulation of G4s’ roles in biology.