Mackenzie Riley Wins Resnik Award

Mackenzie Riley is jazzed about biological chemistry research.

"I started doing research the summer of my first year, and I've been doing it ever since," said Riley, a senior in Carnegie Mellon University's Department of Chemistry. "I'd always been interested in gene expression since DNA is the code for everything, and I saw there were these chemical aspects that I had never heard of before. I wanted to learn more."

Riley is a member of Professor and Chemistry Department Head Bruce Armitage's group. She has worked on multiple projects in the lab, and her independent research focused on RNA imaging and a DNA configuration known as G-quadruplex structures.

G-quadruplex structures are an orientation of DNA outside of the standard double helix chromosome structure. DNA has four base pairs that go together, with adenine and thymine making a pair and cytosine and guanine making a pair. In the double helix, one adenine pairs with one thymine at a time, and one cytosine pairs with one guanine.

In a G-quadruplex structure, four guanines pair together to form a tetrad. These structures are typically found in gene promoter regions, and they have an impact on gene regulation. When they are damaged through oxidation, it can cause cancer or neurodegenerative diseases.

Riley created a variant of a molecule known as a peptide nucleic acid (PNA) that selectively binds to damaged quadruplexes. This PNA could be used in the future to find these damaged quadruplexes.

Riley continued to develop PNAs for different purposes. In her senior year, she worked with both Armitage and Huaiying Zhang, assistant professor in the Department of Biological Sciences, to develop fluorescent PNA that can bind to RNA originating from telomeres, the end points of the chromosome. Being able to tag telemetric RNA (TERRA) will allow for visualization of TERRA's function within cells. Because of Riley's work, the Zhang lab will study the function of TERRA in cancer and tumor formation.

"Mackenzie has done crucial experiments in the telomeric RNA imaging project we are working on in collaboration with Huaiying Zhang's lab," Armitage said. "She has shown that we can hybridize our standard fluorescent PNA probe to a short DNA strand having a quencher dye attached, then TERRA can displace the quencher strand, resulting in the appearance of a fluorescent signal. This modification of our approach will hopefully allow us to use these probes to image TERRA in live cells."

Riley said that while she worked on several different projects during her three years in the Armitage lab, she saw a common thread.

"I really enjoy the work I do. I've done a variety of projects over time, but the thread throughout is studying nucleic acid structures, whether that be with the intent to disrupt those structures and cause some sort of genetic effect or to develop tools to tag them for foundational knowledge," Riley said.

Riley helped other undergraduate students in the Armitage lab, mentoring them through their own projects. She also has served as a supplemental instructor and peer tutor for the Student Academic Success Center, tutoring students in chemistry and biology.

"What has stood out about Mackenzie is the degree to which other undergrads looked to her for leadership," Armitage said. "She's patient, thoughtful and approachable. She doesn't just answer a question, she asks her mentee a question to help them figure out the answer themselves."

Outside of the sciences, Riley swings by the College of Fine Arts to take saxophone lessons, and she keeps up with practice in chamber groups. Riley was also a member of the CMU Jazz Orchestra for three and a half years, and she said that music is a cathartic experience for her.

"No matter how busy I am, I always feel better after I've come out of a lesson or a rehearsal," Riley said. "It's really valuable for me to have the time to engage with music."

For Riley's hard work, she is the winner of Carnegie Mellon's 2024 Judith A. Resnik Award, named for Challenger astronaut and alumna Judith Resnik. The award recognizes an exceptional undergraduate woman graduating in a technical course of study.

"I'm grateful for the award," Riley said. "When you're in the thick of going through your classes and working, it's hard to see the impact of what you're doing on the people around you. Receiving the Resnik Award is a reassurance that what I was doing didn't only matter to me."

In fall 2024, Riley will begin pursuing a Ph.D. in chemistry at the Massachusetts Institute of Technology. Armitage said that he was proud of Riley and her work.

"Mackenzie's strengths are hard to overlook. She is brilliant in the classroom and driven in the lab. She is going to flourish as a scientist at MIT and beyond," Armitage said.