TY  - GEN
N2  - During the past decades, highly pathogenic arthropod-borne viruses (arboviruses) have emerged globally, posing a threat to public health. Arboviruses not only replicate in their vertebrate hosts but feature a dual life cycle with a switch to and from their arthropod vector. This switch is difficult to reproduce experimentally, and the link between infectivity and the molecular features acquired by arboviruses in arthropod vectors or mammalian hosts remains elusive. Moreover, only a few host factors have been functionally described for arbovirus infections.
In this thesis, the tick-borne Uukuniemi virus (UUKV) was used as a surrogate system to explore the molecular features of Phenuiviridae, a large family of highly pathogenic arboviruses in the order Bunyavirales. Label-free proteomic mass spectrometry analysis revealed that GBF1 interacts with the UUKV glycoproteins. Golgicide A-mediated inhibition of GBF1-driven intracellular vesicle trafficking and siRNA-mediated silencing of GBF1 impaired UUKV infection, demonstrating that GBF1 is involved in UUKV replication and egress. GBF1 appeared to be important for a broad range of RNA viruses budding from the endoplasmic reticulum and Golgi networks. Then, lipidomic mass spectrometry analysis indicated that hexosylceramide (HexCer) is enriched in infected cells and in the envelope of UUKV particles. Pharmacological inhibition of the synthesis of the HexCer glucosylceramide (GlcCer) in producer cells resulted in viral progeny with reduced infectivity, likely due to defects in virion binding to target cells. I also found that other bunyaviruses rely on GlcCer for infectious entry. Finally, I established protocols for UUKV production and purification from both tick vector cells and mammalian host cells. Cryo-electron microscopy showed that viral particles were smaller and more heterogenous in size when UUKV was derived from tick cells.
In sum, my thesis allowed the identification of general infection-promoting factors, not only for UUKV, but also for other viruses that bud from the endoplasmic reticulum and Golgi compartments. Strikingly, GlcCer is the first example of a glycolipid mediating virion attachment. My work lays the basis for future studies in virus-receptor interactions and comparative analysis of viral particles produced from their mammalian host and arthropod vector cells. Elucidating these molecular features and related functional processes is paramount to prepare for the emergence of future phenuiviruses and other arboviruses.
TI  - The role of GBF1 and GlcCer in UUKV infection
CY  - Heidelberg
A1  - Uckeley, Zina Maria
KW  - Arbovirus
KW  -  Phenuivirus
UR  - https://archiv.ub.uni-heidelberg.de/volltextserver/32049/
Y1  - 2022///
ID  - heidok32049
AV  - public
ER  -