Structural and Functional Analysis of CPS1: A Virulence Factor in Valley Fever

Grade:

12

Teacher:

Roselyn Paragamac

Drought events are a predictable consequence of global warming, which favors the development and proliferation of the Coccidioides fungus, the causative agent of Coccidioidomycosis, better known as Valley Fever. This fungal respiratory disease is endemic to the southwestern United States, Central, and South America. Many mammals, including rodents, canines, and humans are susceptible hosts of Valley Fever. Currently, there are no specific drug treatments or vaccines against the fungus, which creates significant burdens to the quality of life and the economy in the mentioned regions. Here, we analyze a virulence factor in Coccidioides posidasii called CPS1, which product is an enzyme of unknown function, critical for fungal spherule formation. The gene encoding this protein has been deleted in a novel living vaccine consisting of delta-CPS1 attenuated Coccidioides, undergoing clinical trials in canines. We focused on the two splice variants of CPS1, which only differ from one and the other by a disordered C-terminal domain. The full-length protein was expressed poorly in Saccharomyces cerevisiae and had a decreased cellular viability and total cellular protein compared to the shorter splice variant, CPS1xi. In vitro analysis shows the full-length protein has a higher thermostability than CPS1xi indicating the C-terminal region plays a role in stabilizing the protein through either an intramolecular or intermolecular interaction. Determining the functional differences between CPS1-FL and CPS1xi is critical for developing a vaccine consisting of the attenuated fungus with the deletion of its CPS1 gene.

Project presentation

Research paper