University of San Diego
SPS Award for Outstanding Undergraduate Research
Mobility and Conformational Dynamics of large DNA diffusing through Cytoskeletal Networks
I am currently a senior at the University of San Diego (USD) majoring in Biophysics with minors in Applied Math and Psychology. Growing up in New Hampshire, I fell in love with the natural sciences and was only briefly exposed to physics in high school; this exposure, however, allowed physics to become a source of comfort when beginning schooling in Southern California. Biophysics was the perfect combination between my renewed interests in physics and ongoing love of biology and chemistry. I became involved in the major as an outreach contributor to SPS my sophomore year and as president junior and senior years. Furthermore, I began work in undergraduate research the fall of sophomore year and have continued work year-round. As president of the SPS chapter at USD, I began an outreach relationship with a nearby socioeconomically disadvantaged high school, developing schedules and protocols for the high school students’ visit to introduce them to the opportunities in STEM available to them in higher education. Starting from nothing, the program now boasts steady attendance as SPS chapter members host the high schoolers for a day of lab experiments and exposure to science. The program has since expanded to include visits from an area middle school, in the hopes that younger students can be inspired to explore physics and other sciences. I continue to be involved as a central role to continuing the success of the programs, dedicating much of my free time to organizing these events.
Within the small Physics and Biophysics department at USD, I have focused SPS efforts on expanding community and growth in undergraduate research involvement. This growth is also evident in the research lab where I works by encouraging new undergraduate involvement and tailoring much of my time to training new lab volunteers in protocols and techniques. I am incredibly grateful for the strong role models and support I have in my life, especially for those women who have inspired me in the academic setting. In high school, biology and physics teachers encouraged me to explore the world and push myself academically, mindsets which have become integral parts of my outlook on life. My current academic and research advisor has continued this tradition by modeling passion and dedication. With these women in mind, I focus on encouraging other students to pursue science, especially young women and those who may not have access to the role models.
In the future, I plan on continuing my work with DNA into a PhD program. Ideally, PhD research and post-graduate experiences will lead to a position in cancer research or regenerative medicine, where I can put my foundation to its best purpose. When not in the lab or serving in SPS, I also serve as a Resident Assistant (RA) on the USD campus; I greatly enjoy working with residents and exploring empathic involvement in the larger San Diego community. I am also an avid runner and baker, and enjoy practicing yoga.
The high concentrations of proteins crowding cells greatly influence intracellular DNA dynamics. These crowders, ranging from small mobile proteins to large cytoskeletal filaments such as semiflexible actin and rigid microtubules, can hinder diffusion and induce conformational changes in DNA. The rigidity, mobility, and concentration of crowders all play a role in DNA transport, yet previous studies have mainly focused on the effect of small mobile crowders on transport. At the same time the rigid cytoskeleton has been identified as a key factor suppressing viral transfection and gene delivery. Here, we use fluorescence microscopy and custom single-molecule conformational tracking algorithms to measure center-of-mass transport and time-varying conformational sizes and shapes of single 115 kbp DNA molecules diffusing in networks of actin filaments and microtubules. We determine the dependence of protein concentration (11.4 uM) and rigidity (actin vs microtubules) on DNA dynamics. Corresponding measurements with monomeric actin and tubulin identify the roles that network rigidity versus excluded volume play in transport. Initial results show that crowding by microtubules induces anomalous transport and larger, slower conformational fluctuations of DNA.