IPiB Thesis Defense May 30, 2024: Rachel Cueny

Rachel CuenyRachel Cueny, an IPiB graduate student, will be defending her Ph.D. research on May 30, 2024. Her research in the Keck Lab focused on the roles of a secondary structure in DNA and RNA known as a G-quadruplex.

In a G-quadruplex, four guanines within a chain of nucleotides hydrogen-bond to each other to create a quartet of connected guanines. These G-quartets can stack together to create the G-quadruplex. These structures are associated with both beneficial and harmful processes in humans and other eukaryotes, including gene regulation and telomere regulation, and they have also been found in different oncogenes. Their role in bacteria, however, is not well understood.

“If they were detrimental for cell growth all the time, then we’d expect organisms to evolve away from having G-rich sequences which can form G-quadruplex structures,” explains Cueny. “So we want to know what purposes they serve.”

Cueny investigated how E. coli cells that were mutated to disrupt certain genes would grow in the presence and absence of stabilized G-quadruplexes. She found that when disruptions to genes slowed down translation (the process by which mRNA is used as a template to synthesize proteins), cells grew better when they were grown in the presence of G-quadruplexes.

“It’s just interesting to know more about this biological structure in bacteria and how it compares to what we see in eukaryotes,” says Cueny. “But, there are also medical reasons to investigate G-quadruplexes in bacteria. We know, for example, that G-quadruplex-forming sequences are essential for antigenic variation in Neisseria gonorrhea (a bacterial strain associated with the STI gonorrhea). G-quadruplex-forming sequences may be a key to therapeutic treatments of bacterial infections.” Her research has been published in the Journal of Bacteriology, Nucleic Acids Research, PLOS One, and Critical Reviews in Biochemistry and Molecular Biology.

Cueny came to the IPiB program with a background in structural biology and interest in the Keck Lab’s research. During her first-year lab rotations, Keck’s mentorship style and the collaborative environment of the lab excited her as much as the research. “I really just love the environment of the lab,” says Cueny. “Everyone was willing to help each other. It’s just a really great combination of strong scientists who are also good friends and good labmates. We even formed a recreational volleyball league and we’ve done 14 seasons of volleyball together.”

After graduating, Cueny plans to work as a postdoctoral researcher and eventually pursue a career in academia.

To learn more about Cueny’s research, attend her Ph.D. defense, “Genetic and Biochemical Mechanisms of G-quadruplex Processing” on Thursday, May 30 at 10:00 a.m. CT in Room 1211 of Hector F. DeLuca Biochemical Sciences Building.