Bianca Chavez, an IPiB graduate student, will be defending her Ph.D. research on August 4, 2026. Her research in the Lim Lab examined how telomere loops help to protect telomeres from degradation.
Telomeres are protective caps made of repetitive, single-stranded DNA sequences and proteins. They guard the ends of chromosomes from being degraded during the process of DNA replication and from undergoing erroneous modifications due to dysregulation in their maintenance. Because telomeres shorten a small amount with each DNA replication, telomere length decreases as we age. When cells aren’t replicating their DNA or maintaining telomeres, a telomere can loop back on itself, tucking away its end in a formation known as a T-loop. Chavez’s research sought to confirm that the T-loop protects telomeres from premature shortening and unregulated maintenance.
“When a cell identifies single-stranded DNA, it’s usually a signal that something has gone wrong. The telomere is at risk of being targeted by the cell’s DNA damage response, which can result in the cell starting apoptosis. So, the cell has to have mechanisms that can balance protecting the telomere while allowing necessary enzymes like telomerase to access the telomere during DNA replication,” explains Chavez. “There have been studies that explore how T-loops form, but we haven’t had confirmation about the purposes T-loops serve.”
Chavez confirmed that T-loops convey protection by preventing nucleases (enzymes associated with DNA damage responses) from accessing the ends of telomeres. T-loops also protect telomeres from dysregulated maintenance activity by making telomeres inaccessible to the maintenance enzyme, telomerase. Chavez also found evidence that suggests some telomerase activity is dependent on the T-loop itself, but further exploration is needed.
A first-generation college student, Chavez joined IPiB expecting to study gene regulation and epigenetics, topics that had interested her as an undergraduate student. Once at UW–Madison, Chavez’s priorities shifted to finding robust, interesting research in an environment that would be conducive to her learning style.
“Throughout this process, I have learned to trust my instincts and be confident in my decisions. Graduate school is about learning. I needed to trust myself to find the right research in the right environment with the right people so that I can make progress, but also so that I can make mistakes and learn to let things go and move on. It’s OK to reevaluate, reorient, step away, and catch my breath before figuring out what the next approach should be,” says Chavez.
This mindset also helped Chavez identify new approaches to her research when initial efforts to make and image T-loops collapsed. “Sometimes, as a scientist, you can be so focused on your big question that you can miss other interesting questions that are arising through your struggles. There’s always something to be asking if you take a moment to ask where you can go next.”
Chavez brought this perspective to her mentorship of undergraduate students in the Lim Lab. “I want people, especially young women, to feel like they can be themselves while they are doing science,” says Chavez. “For first generation students and students of color, mentorship is critical to keeping the forward momentum and helping students get where they are going — whether that is graduate school or a job. So, I’ve learned how to mentor from having support systems myself.” Chavez, whose parents are Peruvian and Mexican, also tutored and mentored college-bound high school students through the non-profit organization Centro, which takes a community-based approach to providing programming and services for Madison’s Latinx community.
Chavez plans to pursue a career in industry.
To learn more about Chavez’s research, attend her Ph.D. defense, “The Telomere D-loop Dilemma: Investigation into the Protective Capacity of the Telomere Loop” on Tuesday, August 4 at 1:00 p.m. CT in room 1211 of Hector F. DeLuca Biochemical Sciences Building.
Written by Renata Solan.