Dr. Tanya Paull

Here’s a jeopardy question for the pros: this complex of proteins is present in every known organism and is associated with cancer formation, DNA repair, sexual reproduction and the aging process. But scientists don’t know exactly how it works.

That’s a problem that Tanya Paull, UT Molecular Genetics and Microbiology professor, hopes to solve. She and students in her lab are working to determine how M/R/N, a complex of three proteins, works to complete its many cellular functions.

The lab is focuses on how eukaryotic cells use M/R/N when double-strand breaks occur in DNA. Paull said about half of the researchers in her lab study how the protein complex repairs damaged DNA, which can cause unregulated cell growth, which leads to tumors and cancer in humans.

Other members of the lab ask questions about how a cell uses M/R/N to send signals to its internal structures and communicate proper responses to DNA damage.

The lab workers use a biochemical approach by expressing the recombinant proteins, purifying them, and then studying their functions in biochemical assays in vitro.

In the last year, Paull published two articles regarding the association between M/R/N and another protein complex, ATM, which also plays an important role in DNA damage repair. ATM acts as a tumor suppressor because it creates proteins that inform cells that they need to repair damaged DNA, which could otherwise lead to cancer. Paull showed that this tumor-suppressing function wouldn’t work without M/R/N.

It’s important for scientists to fully understand how M/R/N works because it is involved in many functions and cell processes, Paull said. “It’s one of the last remaining enzymes associated with [DNA] repair and recombination that we don’t understand”.

And Paull expects students in her lab to work hard to gain that knowledge. The lab staff includes seven graduate students, one postdoctoral fellow, one technician and some undergraduate students.

“We’re really focused on getting results,” she said. Her students have freedom to make their own schedules, and Paull said there are often people in the lab late into the night.

Students also are free to decide what research projects they will undertake and how they will design the experiments, said Venugopal Bhashara, a 5th-year graduate student in the lab.

“[Paull] takes a lot of interest in us,” he said. “She’s very eager and curious about what’s going on with our work.”

Bettina Lengsfeld, another 5th-year graduate student in the lab, said the same type of one-on-one attention is what first drew her to work with Paull.

“At any moment if I need to ask a question, I can ask a question,” Lengsfeld said. “It’s comforting to have someone who can give me an answer.”