Intellectual Merit: The genetic information in living organisms is stored as linear polymers of four DNA elements: guanine, cytosine, adenine, and thymine. Chemical modifications of genomic DNA have principal roles in both natural gene regulation and DNA damage. In the cell, gene activity is regulated via enzymatic modification of cytosine (methylation). Cytosine modification rates are vital as their alteration can compromise cell function and organism survival. Unlike this modification of cytosine, which serves a regulatory role, modification of guanine (oxidation) is detrimental to the integrity of the genetic information. Left unrepaired, this common type of guanine damage (lesion) can lead to genome instability and mutations. In the human genome, there are many occurrences of cytosine and guanine being adjacent (clustered). Repair of a guanine lesion neighboring a modified cytosine is known to be compromised. Likewise, normal cytosine modification rates are altered within the sites containing a modified guanine. The chemical reasons for these adverse enzymological effects have yet to be determined. One of the missing links is the characterization of DNA with modified guanine and cytosine clustered together. To close this gap, the project aims to investigate the fundamental biophysics (stability, structure and dynamics) of DNA with a guanine lesion adjacent to a modified cytosine, using nuclear magnetic resonance (NMR) techniques along with molecular dynamics simulations. Such a comprehensive study of linked damage and regulatory modifications in DNA will be performed for the first time, pioneering new research in genome stability and regulation.
Broader Impacts: The project engages students at Western Washington University, a primarily undergraduate institution. Every effort is made to include students from minority and underprivileged populations. The participating students are involved in modern, inter-disciplinary academic research spanning areas of chemistry, biology, physics and computer science, a combination of principal scientific and instructional value. The project gives the students an early opportunity to experience the full scope of academic research in the lab. The students also communicate the results as co-authors, which further advances their professional development. As a benefit to a wider student body, some of the DNA samples developed during this investigation will be used for classes taught at Western Washington University. Overall, the project helps to integrate research with education and prepare undergraduate students for industry careers and Ph.D. studies.
