Dissertations, Theses, and Capstone Projects
Date of Degree
9-2024
Document Type
Dissertation
Degree Name
Ph.D.
Program
Biology
Advisor
Reza Khayat
Committee Members
Paul Gottlieb
Ruth Stark
John Dennehy
Enrique Rojas
Keywords
Virology, Cystovirus, Bacteriophage, Molecular Biology
Abstract
The Cystoviridae is a unique family of double stranded RNA bacteriophage that fuses its outer viral membrane with the lipopolysaccharide membrane of its Gram-negative host. In a series of studies, we determined the specifics of Cystoviridae host binding and the requirements of host fusion. The outer membrane vesicles (OMVs) secreted by the host inhibit Cystoviridae infection. We studied the interaction between OMVs and Cystoviridae to observe the host requirements for binding Cystoviridae. We determined that Cystoviridae strains Phi 8 and Phi 12 recognize the core polysaccharide and lipid A of the host lipopolysaccharide (LPS) for binding. The P6 protein of the Cystoviridae spike complex is suggested to allow fusion of the phage to the host cell. We investigated the P6 residues required for host fusion. The P6 residues of Phi 6 and Phi 12 that are required for fusion are predicted to be in alpha helices. We hypothesize that fusion occurs through coil-to-coil interactions. To observe details of the lifecycle of Phi 8 we utilized in situ cryo electron microscopy. Our results indicate the presence of Cystoviridae in different stages of capsid biogenesis. Lastly, we expressed different forms of the envelope forming protein P9 to purify vesicles containing P9. These vesicles have the potential to determine the P3 residues required for host binding.
Recommended Citation
Robinson, Charles F. IV, "Mechanism of Host Recognition by the Bacteriophage Cystoviridae" (2024). CUNY Academic Works.
https://academicworks.cuny.edu/gc_etds/5951