IPiB Thesis Defense December 7, 2023: Katherine Senn

Kathy SennKatherine (Kathy) Senn, an IPiB graduate student, will be defending her Ph.D. research on December 7, 2023. Her research in the Hoskins Lab focuses on regulation of one of the steps in mRNA processing required for gene expression.

During the splicing process, the regions of mRNA that do not code for a protein (known as introns) are removed, resulting in strands of mRNA that do code for proteins. The parameters around where and when the splicing process can occur are precise and complex. “The boundaries where introns are removed are very specific. Removing an intron with the wrong boundaries or at the wrong time could mean that proteins are not produced correctly,” explains Senn.

Senn’s research used the yeast Saccharomyces cerevisiae to closely examine the function of proteins that make up the spliceosome — a macromolecular complex responsible for RNA splicing. Specifically, she examined how RNA processing is impacted by the protein Fyv6.

“This protein was not previously associated with splicing, but we’ve determined that in yeast it is part of the spliceosome, and it needs to be present for correct intron boundaries to be identified,” says Senn. “It’s exciting because the spliceosome has been studied for decades, and yet, there’s still this new protein that we didn’t know about. So, we wanted to know what it was doing in splicing.”

Using yeast genetics, cryo-electron microscopy, and biochemical research methods, Sennanalyzed both the form and function of Fyv6. She learned that in the absence of Fyv6, the spliceosome does not recognize correct boundaries — especially at the 3ʹ end — of a subset of introns. Additionally, Fyv6 function relies on its interactions with other proteins in the spliceosome. Interference with those interactions can also result in misidentified boundaries. Her research on Fyv6 has been published in RNA.

Senn knew that she was interested in studying the spliceosome after completing her rotations in the IPiB program. She originally studied the RNA processing complex and alternative splicing in the lab of Heidi Dvinge. Sadly, Dvinge passed away suddenly in 2019. Senn found a new home and welcoming community in the Hoskins Lab.

“I learned a lot from Heidi, and I was very lucky to be her student for the two years that we had together,” recalls Senn. “It was a big transition going to a new lab and everyone was very helpful and understanding.”

For Senn, the IPiB community drew her to the program from the beginning. “I went to college at a school that was big enough to have various opportunities but small enough where I could know everyone in my program and I could get to know my professors. When I interviewed with the IPiB program, I saw a similar community, where everyone knew each other, professors were available to students, and people were very friendly. That was a big draw for me.” Senn helped to support the IPiB community as Outreach Chair for the Graduate Leadership and Development Committee.

After graduating, Senn plans to work in industry.

To learn more about Senn’s research, attend her Ph.D. defense, “Regulation of pre-mRNA Splicing Efficiency and Fidelity in Saccharomyces cerevisiae,” on Thursday, December 7 at 2:00 p.m. CT in Room 1211 of Hector F. DeLuca Biochemical Sciences Building.