Ph.D. candidate discusses mathematical model of gene transcription

Tamra Heberling, a doctoral candidate from the Department of Mathematical Sciences, presented her lecture, “They Transcribe with a Little Help from their Friends: A Mechanistic Model for Cooperative Behavior of RNA Polymerases,” on Monday, Jan. 25 in the Procrastinator Theatre. Heberling’s research focuses on mathematical models of gene transcription.

Along with a research team, Heberling has been studying how DNA is transcribed, and why it seems to be transcribed faster when there are more RNA Polymerases (RNAP’s.) The team focused on E. Coli bacteria, which is commonly studied because of the fast rate at which it doubles, allowing researchers to get a large amount of information from it.  

Transcription is a step in the process by which amino acids are formed. An RNAP initiates onto the DNA strand. It then produces a complementary RNA strand, in a process called elongation. It then gets off the DNA strand and releases the RNA. A ribosome then reads the messenger RNA and produces an amino acid, which is where proteins come from. When the RNAP moves down the strand of DNA, it often experiences short pauses. When this happens, the RNAP can get backed up, much like cars on a road.

Heberling’s research is based off previous research on transcription. She summarized the results of the first piece of research, “If you have more RNAP’s close together they not only all transcribe faster, but individually go faster.” She continued, “That’s what I mean by ‘they transcribe with a little help from their friends.’ They’re all working together in this group effort.”

One explanation this previous research pointed to was that one RNAP could push another paused RNAP forward. The piece this research was missing was why this happened. More research came out studying how coiling in strands of DNA affect how RNAP’s travel across the strand and transcribe. This research focused on single molecule transcription. The question Heberling wants to answer is why transcription happens faster with multiple RNAP. To do this, she and her team combined the ideas from the previous research and set out to create a model that can explain this phenomenon. “Our idea was let’s take this single molecule data and information and really put it into what happens with many molecules,” Heberling said.

They built the idea of torque into a mathematical model, simulating transcription with and without torque, and found that torque causes shorter pauses between RNAP’s. The team now proposes that torque is the mechanism that causes cooperation between RNAP’s. This prevents collisions, and makes the process go faster. Heberling and her team are now looking for experts in biology to collect more data so they can fine-tune their model.

The lecture was part of the Kopriva Science Seminar Series. Heberling was also chosen to be a part of the Kopriva Graduate Student Fellowship Program. Both are funded through endowments created by MSU microbiology graduate Phil Kopriva, who died in 2002. Heberling received her undergraduate degree from Northeastern University in Boston, and has been at MSU both for her master’s and Ph.D., which she is close to completing.

Lisa Davis from the Department of Mathematical Sciences shared her enthusiasm for Heberling’s work at MSU, saying, “We’re very proud of her. Her activities in the department have been exemplary. She’s a very energetic student.” For more information on the Kopriva Science Seminar Series head to montana.edu/lettersandscience/kopriva.html.