Raegan Herdman

Contributing Writer

On Thursday, Nov. 21, The College of Wooster was visited by Derrick Morton, assistant professor of biological sciences and gerontology at the University of Southern California (USC).   Morton’s visit was part of the biology department’s Life Science Seminar Series. 

Morton’s career began at Eastern Kentucky University, where his first research project was testing students for antibiotic resistant strains of bacteria to explain a rise of illness on campus. After that, he knew that research was right for him. Morton studied cancer cells as he worked towards his doctorate in biology at Clark Atlanta University, and then shifted to RNA science in his post-doctoral work. 

Now working as the Primary Investigator of a lab at USC, he spends most of his time directing the lab, writing grants and papers and working with graduate students. Morton’s lab studies the RNA mutations that cause PCH1B —  a neurological disorder in infants that causes neurodegeneration of the pons, cerebellum and motor neurons. Newborns with the disease are initially healthy, but fail to meet developmental milestones in their first months at home, and, after testing, are diagnosed with PCH1B.

RNA processing is not as well-known as its sister processes: replication, transcription and translation, but it is still an important part of gene expression and cellular function. Once mRNA is released into the cytoplasm of the cell, it is translated by ribosomes into functional proteins until the mRNA is broken down. If the mRNA remains in the cytoplasm for too long, it causes overproduction of its associated protein, which can overstimulate other cells, impede cell functioning and induce other harmful effects. RNA exosomes are responsible for breaking down the mRNA, preventing this overproduction of protein. Morton’s lab utilizes Drosophila fly models to study how mutations in the RNA exosomes can cause PCH1B.

RNA exosomes are expressed in all cells and in all species. This can come as a surprise, as flies and humans do not seem to have much in common; however, the RNA exosome is very well conserved across evolution, meaning it is virtually unchanged throughout all species. The exosome’s function of regulating the levels of mRNA is critical to the survival of all species. Mutations affecting the exosome would be catastrophic to the affected individual, preventing the mutation from being passed down to further generations. Patient populations of PCH1B are very small, making the disease difficult to study in humans.

“What makes model systems [such as Drosophila flies] such great tools to use … is the less genetic diversity,” Morton said. “You can be more confident that the phenotypes you’re seeing are not because of the background of the organism, but because of the changes you’ve made.” 

To study mutated RNA exosomes, Morton and his colleagues edit the genes controlling the subunits of the RNA exosome, which are almost identical to the corresponding genes in humans with PCH1B. The flies with the mutated genes showed severe defects in both brain anatomy and molecular functioning. 

Morton and his lab hope to enhance the understanding of PCH1B, in the hopes of eventually finding more clues to an accessible treatment. To learn more about Professor Morton’s research, visit themortonlab.com