Date of Award
2026
Document Type
Thesis (Ph.D.)
Department or Program
Biochemistry and Cell Biology
First Advisor
Surachai Supattapone, MD, PhD, DPhil
Abstract
Neuroinvasive and reassortment-competent, mosquito-borne orthobunyaviruses are a threat to public health. La Crosse virus (LACV) of the California serogroup (CSG) orthobunyaviruses is particularly virulent, leading to neuron loss through apoptosis in patients with LACV encephalitis. With no targeted treatments or vaccines clinically available, patients are left with lifelong neurological deficits.
The aim of this work is to discover host cell factors that act in pro- and anti-viral manners. I conducted a series of whole genome CRISPR survival screens, two knockout and one activation, in neuroblastoma cells to identify host cell genes and pathways that prolonged infection survival. I screened for survival of each LACV and the lesser pathogenic but highly seroprevalent CSG member Inkoo virus (INKV).
All three large-scale screens confirmed that intrinsic apoptosis is a primary driver of orthobunyavirus host cell death. The LACV and INKV knockout survival screens further identified impaired host cell mitochondrial energy production as protective. Perturbing metabolism through mild hypothermia and carbon source substitution replicated the survival advantage not only for LACV and INKV, but also the non-CSG orthobunyavirus Bunyamwera virus (BUNV). The LACV activation survival screen identified TGFβR2 as an antiviral factor, which was validated by genetic follow-ups. At the intersection of many cellular signaling pathways, TGFβR2 has not previous been characterized as a cell autonomous antiviral effector.
In combination, the three genetic screens reported herein provided multiple novel interventions to increase survival of orthobunyavirus infections in culture. These interventions and insights could translate into new clinical treatments for orthobunyavirus infections. Furthermore, the ranked lists of genes contributing to host cell survival or death from each of the three screens contain additional targets for future investigations.
Recommended Citation
Francomacaro, Lisa M., "A Genetic Investigation into Host Pathways Driving Orthobunyavirus Mediated Cell Death" (2026). Dartmouth College Ph.D Dissertations. 458.
https://digitalcommons.dartmouth.edu/dissertations/458
Included in
Biochemistry Commons, Cell Biology Commons, Molecular and Cellular Neuroscience Commons, Molecular Genetics Commons, Virology Commons
