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The Regeneration Connection

A fascination with tissue restoration inspires a UNLV professor and undergraduate student to team up to understand how frogs might impact the fate of humankind.

Research  |  Jul 7, 2016  |  By Raegen Pietrucha
Diana Pena and Ai-Sun (Kelly) Tseng

UNLV's research programs has given undergraduates like Diana Pena, left, the chance to gain invaluable experience in the labs of their professors. Peña is working with life sciences professor Ai-Sun (Kelly) Tseng, who studies tissue regrowth. (Josh Hawkins/UNLV Photo Services) 

When it comes to someday harnessing regenerative superpowers that even Wolverine and Deadpool might envy, UNLV life sciences professor Kelly Tseng has put her faith in an unlikely hero: Xenopus laevis, the South African clawed frog.

An interest in cell fate — how cells grow, proliferate, and ultimately assume a well-defined role — led her toward this powerful creature early in her career because of its ability to adapt its cells to different contexts, regrowing a number of body parts seemingly at will. When Tseng joined UNLV’s faculty in 2012, she brought this research — and critter — with her, in the hopes that she might someday transfer the frogs’ impressive regenerative capabilities to humans.

As another kind of fate would have it, Diana Peña once watched video on nervous tissue regeneration in her high school AP biology class. It sparked a scientific curiosity in the first-generation UNLV Honors College student that led to her double-major in biology and psychology. So when she heard about the work happening in the Tseng Lab from a fellow student, and understanding that the research could go on to help people overcome debilitating medical conditions, she decided to team up with Tseng and the frogs to help make a difference.

Here’s the story of the two-year journey that would help both professor and student grow closer to understanding tissue regeneration in a mighty amphibian as well as its implications for humanity.


Tseng: “It all began when Diana emailed me to say she was interested in working in my lab.”

Peña: “I thought it was awesome that Dr. Tseng’s research could go on to help people overcome their medical issues someday. Her work was more and more interesting to me as I learned more and more about the possibilities in the field, what we can do for humans.”

Tseng: “As part of my application process for undergraduates, besides asking for grades, I ask to know why the student is interested in research because in my lab, they’ll spend between 15-20 hours a week — sometimes more — doing research.

“Although I get quite a number of applicants, when I interviewed Diana, I knew she would be a great fit for the lab. She was really committed to putting in the work and the time that’s necessary, and she seemed to inherently understand that what it actually entailed would be well beyond her normal course load — a course load that, especially as a double major, is not insignificant.”


When Peña was accepted to join Tseng’s lab, her training actually began outside of it. After more than a month of biweekly training sessions, Peña was tested to ensure she could translate observations into the appropriate action steps that would enable her to begin participating in the lab’s experiments—and could do this independently.

Once Peña passed this test, Tseng granted her access to the lab. There, Peña began learning firsthand how to conduct experiments. She paced herself at one experiment per week. It took more than a year of trial and error, a process that would frustrate even the most patient undergraduate researcher, before Peña celebrated her first big success in the lab: She was able to perform her experiments consistently and successfully over a two-week period.


Peña: “You learn throughout the entire process of doing research. You’re always learning new techniques, and though we’re not doing particularly difficult tasks, it can take a while to get your first win.”

Tseng: “Many students struggle to overcome experimental failure. Some students get frustrated when experiments don’t work the first time and they have to repeat them. We have to make sure that our results are consistent and reproducible, though. We can’t just perform experiments once and move on. These days, experimental failure is normal to Diana — so normal that she doesn’t even see it as a challenge. She just pushes on. Diana quickly picked up on the realities of what we do.”

Peña: “I realized after many experiments that failure is just part of research.”


Researchers have studied the fascinating process of regeneration since the 1700s. It’s the subject of science and superhero mythology alike, and with any luck, the work being done in Tseng’s lab will someday lead to a confluence of the two.

Xenopus laevis is able to regenerate a number of tissues, including muscle and nervous tissue. Humans possess only a limited ability to do this—an ability that is believed to be gradually lost as humans age. The idea behind Tseng’s and Peña’s research is that, through studying model organisms like Xenopus and gaining a deeper understanding of the role insulin plays in its regenerative processes, scientists will someday be able to use the knowledge they obtain from the frogs and apply it to humans.

Research of this nature has the potential to dramatically improve the lives of people with degenerative diseases. Someday, it may even lead to the regeneration of previously amputated human tissues, organs, and limbs. Although this type of research has many aims, without the fundamental biology knowledge Tseng and Peña gain in the lab, we can’t even begin to hope for these life-changing therapies to come to fruition.


Peña: “You hear the term ‘critical thinking’ getting thrown around a lot — how universities want to make students good critical thinkers. Coming into the lab, I definitely was not. Now that I’ve worked in the lab, had the opportunity to experiment, read research articles, and discussed research with Dr. Tseng and other faculty members, I think I am a much better critical thinker.”

Tseng: “This is part of the value of research for undergraduates — for everyone, really. But we especially need to expose undergraduates to research because it teaches them critical thinking skills that they don’t necessarily have the opportunity to gain or practice in a lecture. In a lab, students learn how to structure experiments, ask scientific questions, and analyze data and results. It also helps bring all the things we discuss in biology class to life.”

Peña: “Dr. Tseng always asked me to think about what I might be doing wrong, what might be causing my failed experiments, what I could change. She got me asking questions. I don’t just take everything that I hear or read or assume as truth anymore. I scrutinize it. I think about ways things could be done differently and improved upon.”

Tseng: “Besides being a good learning experience, student researchers are actually contributing to scientific knowledge. Basic biology research has applications to real life, and it helps better society. Being able to do this research together allows faculty to show students what it’s like—how difficult it actually is, but also how rewarding.”


Peña has reaped many rewards from being an undergraduate researcher in Tseng’s lab. In addition to the practical and analytical skills she’s gained, Peña was recognized as one of this spring’s outstanding graduates and garnered UNLV’s 2016 Office of Undergraduate Research Undergraduate Scholar Award. She also learned how to write research proposals, which resulted in a 2015 National Science Foundation (NSF) Research Experience for Undergraduates (REU) Fellowship as well as funding from the NSF REU in 2014. In fact, Diana’s work is so highly esteemed in the undergraduate community that she had to decline additional funding offered to her from the NSF and the National Institutes of Health because their fellowship programs didn’t permit overlap.   

Although many recognize that research costs money, the subject of undergraduate research funding isn’t one that comes up nearly as often as it should, Tseng and Peña indicated. Outside of her two REU fellowships — one that lasted a full academic year, and one that covered a summer term — Peña has volunteered her time to the lab.

Research funding enables undergraduates like Peña to focus their energy on their academic endeavors while attending college. It helps them feel supported, keeps them motivated to accomplish their research goals, and makes them more competitive candidates in the job and academic markets.

For all this, Peña feels extremely grateful.

Most biology research funding comes from the federal government. Not surprisingly, when Peña received a campaign call during the primaries, the first thing she asked was the candidate’s position on science funding.

If nothing more, exposure to the financial side of research has given Peña a deeper understanding that, without proper support for biologists like her faculty research mentor Tseng, there never would’ve been a research opportunity for her to begin with. Fortunately, because UNLV understands that ensuring student success is as important as increasing research funding—and that the two are in fact inextricably linked—both are part of the university’s Top Tier strategic plan.


Tseng’s and Peña’s work to understand tissue regeneration will continue — together for a bit longer, then separately as Peña heads toward a bright future in medicine.

Peña: “I will be applying to medical school in the summer, but I will be taking a year off. During that year, though, I’ll be doing some research here in the lab.”

Tseng: “We won’t let her go. Diana’s contributed very valuable data and results to the project that we expect to be published in the near future. She’s a great student, and I’ve been thrilled to see how she’s developed as a researcher. Her work is excellent, and she’s helped the lab move forward.”

To learn more about research opportunities for students, contact the Office of Undergraduate Research.