Séminaire CIRI (06.10.2023) : Dr. Emmanuelle QUEMIN
| When |
Oct 06, 2023
from 09:00 AM to 10:00 AM |
|---|---|
| Where | Salle conf IBCP |
| Contact Name | Christiane Riedel |
Emmanuelle QUEMIN, Institute for Integrative Biology of the Cell (I2BC): « Studying poxvirus infection using cellular cryo electron tomography »
Abstract: Poxviruses are widely distributed large and enveloped dsDNA viruses. Historically, Variola virus caused smallpox epidemics before its eradication after the first international vaccination campaign with Vaccinia virus (VACV). The recent multi-country outbreak of Monkeypox virus stressed that zoonotic poxviruses can still spread in human populations. Over the years, VACV has become a powerful model to study poxviruses and investigate key aspects of pox-biology that remain unknown.
Similar to other poxviruses, VACV infection cycle takes place in the host cytoplasm directly and leads to massive cellular remodelling. In my group, we focus on VACV replication and assembly with the goal of deciphering the molecular mechanisms underlying cellular membrane remodelling. At early stages of infection, viral genome replication occurs within tightly apposed cisternae of the endoplasmic reticulum (ER). This replication compartments then appears to dissociate concomitant with virion assembly that involves a unique mechanism of viral membrane formation. Current working model includes the recruitment of ER-derived vesicles to the assembly site, which are subsequently ruptured-open and associate into typical VACV crescents with open membrane ends. Following packaging of the viral genome, the crescents are closed, forming the spherical immature virions. Further maturation steps are then necessary to make the characteristic infectious mature virions.
Fundamental questions remain open in the field on the formation of different viral compartments or factories dedicated to replication and assembly. Furthermore, the complex mechanism of VACV assembly is still poorly understood. We have implemented an integrative approach including correlative imaging and cellular cryo electron tomography to study VACV replication and assembly at the molecular level. In parallel, we develop complementary in vitro reductionist approaches with membrane model systems to investigate the role of specific viral proteins. Overall, we aim at improving our understanding of poxviruses to develop novel antiviral strategies and uncover cellular membrane dynamics hijacked during infections.