Virginia Tech
Understanding Host-Pathogen Interactions of Rift Valley Fever Virus That Contribute to Viral Replication
Abstract
dc:description.abstractRift Valley fever virus (RVFV) is a negative-sense RNA virus that is classified as an overlap select agent by the USDA and the HHS. It was first discovered in the Rift Valley of Kenya in the early 1930s. RVFV is an arbovirus that is transmitted by mosquitoes and infects ruminants and humans. RVFV in humans causes an acute self-limiting febrile illness but in a small percentage of cases, a severe version is noted by ocular disease, hepatitis, hemorrhagic fever, and death. In ruminants, the disease is similar with young livestock being the most susceptible. RVFV is also known to cause "abortion storms" where infected pregnant ruminants abort their fetuses with a near 100% fatality rate. Viruses are obligate intracellular parasites utilizing host-factors to replicate. This study identified three host-protein interactors of the viral Gn and L proteins that aid in viral replication. UBR4 was determined to be an interactor of Gn via immunoprecipitation followed by either LC/MS/MS or western blot analysis. Its inhibition via siRNA or CRISPR-Cas9 knockout showed a reduction of viral titers and viral RNA production. It was determined that UBR4 specifically affects viral RNA production and not entry or egress. Conversely, CK1α and PP1α were identified as binding partners of the L protein using similar methods. CK1α, a kinase, and PP1α, a phosphatase, were chosen for further verification due to data demonstrating the L protein is phosphorylated on at least one serine residue, in addition to PP1α already being shown to impact RVFV replication. Inhibition of CK1 and PP1 via small molecule inhibitors, D4476 and 1E7-03, respectively, showed a decrease in viral titers and RNA production. Strand-specific RT-qPCR demonstrates that CK1 and PP1 impact genomic replication. Upon treatment with D4476 a decrease in L protein phosphorylation was observed. Additionally, it has already been shown that treatment with 1E7-03 increases L protein phosphorylation. These data indicate that CK1 and PP1 modulate L protein phosphorylation, contributing to changes in RVFV replication. This study identifies three host-proteins that affect viral replication, which could be used as a foundation for host-based therapeutic and vaccine development.
Degree
thesis:*- Name thesis:degree_name
- Doctor of Philosophy
- Level thesis:degree_level
- doctoral
- Discipline thesis:degree_discipline
- Biomedical and Veterinary Sciences
- Department dc:contributor.department
- Biomedical and Veterinary Sciences
- Grantor dc:publisher
- Virginia Tech
- Year dc:date.issued
- 2022
Author and committee
dc:creator, dc:contributor.*- Author dc:creator
-
- Bracci, Nicole R.
- Chair dc:contributor.committeechair
-
- Kehn-Hall, Kylene Wesley
- Committee members dc:contributor.committeemember
-
- Duggal, Nisha K.
- Bertke, Andrea S.
- Caswell, Clayton Christopher
Subjects
dc:subject × 5Rights
dc:rights- Statement dc:rights
-
- In Copyright
- Licence dc:rights.uri
- Language dc:language.iso
- en
Identifiers
dc:identifier.*- Dc Identifier Other
- vt_gsexam:34151
- OAI identifier oai:identifier
- oai:vtechworks.lib.vt.edu:10919/109644